Centrifugal Fire Pump Vacuum System is intended for preliminary filling of the suction line and pump with water when water is taken from an open water source (reservoir). In addition, using a vacuum system, a vacuum (vacuum) can be created in the housing of a centrifugal fire pump to test the tightness of a fire pump.

Currently, two types of vacuum systems are used on domestic fire trucks. The first type of vacuum system is based on gas jet vacuum apparatus(GVA) with a jet pump, and at the base of the second type - vane vacuum pump(volumetric type).

Conclusion on the question: modern brands of fire trucks use various vacuum systems.

Gas jet vacuum systems

This vacuum system consists of the following main elements: a vacuum valve (shutter) installed on the manifold of a fire pump, a gas-jet vacuum apparatus installed in the exhaust tract of a fire engine engine, in front of the muffler, a HVA control mechanism, the control lever of which is located in the pump compartment, and a pipeline connecting the gas-jet vacuum apparatus and the vacuum valve (shutter). Schematic diagram the vacuum system is shown in Fig. 1.

Rice. 1 Diagram of the vacuum system of a centrifugal fire pump

1 - the body of the gas-jet vacuum apparatus; 2 - damper; 3 - jet pump; 4 - pipeline; 5 - opening to the cavity of the fire pump; 6 - spring; 7 - valve; 8 - eccentric; 9 - eccentric axis; 10 - eccentric handle; 11 - vacuum valve body; 12 - hole; 13 - outlet pipe, 14 - valve seat.

The body of the gas-jet vacuum apparatus 1 has a flap 2, which changes the direction of movement of the exhaust gases of the fire engine engine either to the jet pump 3 or to the exhaust pipe 13. The jet pump 3 is connected by pipeline 4 to the vacuum valve 11. The vacuum valve is installed on the pump and communicates with it through hole 5. Inside the body of the vacuum valve, springs 6 to the seats 14 are pressed against two valves 7. When the handle 10 is moved with the axis 9, the eccentric 8 pushes the valves 7 away from the seats. The system works as follows.

In the transport position (see Fig. 1 "A") the shutter 2 is in the horizontal position. Valves 7 are pressed against the seats by springs 6. The exhaust gases of the engine pass through the housing 1, the exhaust pipe 13 and are discharged into the atmosphere through the muffler.

When taking water from an open water source (see Fig. 1 "B") after connecting the suction line to the pump, press the lower valve down with the handle of the vacuum valve. In this case, the cavity of the pump through the cavity of the vacuum valve and the pipeline 4 is connected to the cavity of the jet pump. Flap 2 is moved to a vertical position. The exhaust gases will be directed to the jet pump. A vacuum will be created in the suction cavity of the pump and the pump will be filled with water at atmospheric pressure.

The vacuum system is switched off after filling the pump with water (see fig. 1 "B"). Moving the handle, the upper valve is squeezed out of the seat. This pushes the bottom valve against the seat. The suction cavity of the pump is disconnected from the atmosphere. But now pipeline 4 will be connected to the atmosphere through hole 12, and the jet pump will remove water from the vacuum valve and connecting pipelines. This is especially necessary for winter period to prevent water freezing in pipelines. Then the handle 10 and the shutter 2 are placed in their original position.

Rice. 2 Vacuum valve

(see Fig. 2) is designed to connect the suction cavity of the pump with a gas-jet vacuum apparatus when taking water from open reservoirs and removing water from pipelines after filling the pump. In the valve body 6, cast from cast iron or aluminum alloy, there are two valves 8 and 13. They are pressed against the seats by springs 14. When the handle 9 is "away from you", the eccentric on the roller 11 pushes the upper valve away from the seat. In this position, the pump is disconnected from the jet pump. Moving the handle "towards you", we squeeze the lower valve 13 from the seat, and the suction cavity of the pump is connected to the jet pump. With the handle upright, both valves will be pressed against their seats.

In the middle part of the body there is a plate 2 with a hole for attaching the flange of the connecting pipeline. In the lower part there are two holes covered with eyes 1 made of organic glass. The body 4 of the light bulb is attached to one of them. The filling of the pump with water is controlled through the peephole.

On modern fire trucks in the vacuum systems of fire pumps, instead of a vacuum valve (shutter), cork water taps in a common design are often installed to connect (disconnect) the suction cavity of a fire pump with a jet pump.

Vacuum shutter

Gas jet vacuum apparatus designed to create a vacuum in the cavity of the fire pump and the suction line when they are pre-filled with water from an open water source. On fire trucks with gasoline engines, single-stage gas-jet vacuum apparatuses are installed, the design of one of which is shown in Fig. 3

Housing 5 (distribution chamber) is designed to distribute the flow of exhaust gases and is made of gray cast iron. Inside the distribution chamber, there are beads machined for the seats of the butterfly valve 14. The body has flanges for attaching to the engine exhaust tract and for attaching a vacuum jet pump. The damper 14 is made of heat-resistant alloy steel or ductile iron and is fixed on the axis 12 by means of a lever 13. The damper axis 12 is assembled on graphite grease.

By means of the lever 7, the axis 12 is rotated, closing either the opening of the housing 5 or the cavity of the jet pump with a damper 14. The jet vacuum pump consists of a cast iron or steel diffuser 1 and a steel nozzle 3. The jet vacuum pump has a flange for connecting a pipeline 9, which connects the vacuum chamber a jet pump with a fire pump cavity through a vacuum valve. With the vertical position of the damper 14, the exhaust gases pass into the jet pump, as shown by the arrow in Fig. 3.25. Due to the vacuum in the vacuum chamber 2 through the pipeline 9, air is sucked from the fire pump when the vacuum valve is open. Moreover, the higher the rate of passage of the exhaust gases through the nozzle 3, the more vacuum is created in the vacuum chamber 2, the pipeline 9, the fire pump and the suction line, if it is connected to the pump.

Therefore, in practice, when a vacuum jet pump is operating (when taking water into a fire pump or checking it for leaks), the maximum engine speed of a fire engine is set. If the flap 14 closes the hole in the vacuum jet pump, the exhaust gases pass through the body 5 of the gas jet vacuum apparatus into the muffler and then into the atmosphere.

On fire trucks with a diesel engine, two-stage gas-jet vacuum apparatuses are installed in vacuum systems, which resemble single-stage ones in structure and principle of operation. The design of these devices is capable of providing short-term operation of the diesel engine in the event of back pressure in its exhaust tract. A two-stage gas-jet vacuum apparatus is shown in Fig. 4. The vacuum jet pump of the apparatus is flanged to the housing 1 of the distribution chamber and consists of a nozzle 8, an intermediate nozzle 3, a receiving nozzle 4, a diffuser 2, an intermediate chamber 5, a vacuum chamber 7 connected to the atmosphere through a nozzle 8, and through an intermediate nozzle - with intake nozzle and diffuser. A hole 9 is provided in the vacuum chamber 7 to connect it to the cavity of the centrifugal fire pump.

Scheme of operation of the electric pneumatic drive for switching on the GVA

1 - gas-jet vacuum apparatus; 2 - pneumatic cylinder of the GVA drive; 3 - drive lever; 4 - EPK for switching on GVA; 5 - EPK for switching off GVA; 6 - receiver; 7 - pressure limiting valve; 8 - toggle switch; 9 - atmospheric outlet.

To turn on the vacuum jet pump, it is necessary to turn the flap in the distribution chamber 1 to 90 0. In this case, the damper will block the exit of diesel exhaust gases through the muffler to the atmosphere. The exhaust gases enter the intermediate chamber 5 and, passing through the intake nozzle 4, create a vacuum in the intermediate nozzle 3. Under the action of the vacuum in the intermediate nozzle 3, atmospheric air passes through the nozzle 8 and increases the vacuum in the vacuum chamber 7. This design of the gas-jet vacuum apparatus makes it possible to effectively operate the jet pump even at low pressure (speed) of the exhaust gas flow.

Many modern fire trucks use the GVA electropneumatic drive system, the composition, design, principle of operation and operation features of which are described in the chapter.

Rice. 4 Two-stage gas jet vacuum apparatus

The procedure for working with a HVA-based vacuum system is shown using the example of model 63B (137A) tank trucks. To fill the fire pump with water from an open water source or check the fire pump for leaks, you must:

• make sure that the fire pump is tight (check the tightness of all taps, valves and valves of the fire pump);
• open the lower valve of the vacuum seal (turn the handle of the vacuum valve "towards yourself");
• turn on the gas-jet vacuum apparatus (with the corresponding control lever using the damper in the distribution chamber, shut off the exhaust gases outlet through the muffler into the atmosphere);
• increase engine idle speed to maximum;
• observe the appearance of water in the sight glass of the vacuum valve or the indication of the manovacuum meter on the fire pump;
• when water appears in the sight glass of the vacuum valve or when the vacuum pressure gauge in the pump is at least 73 kPa (0.73 kgf / cm 2), close the lower valve of the vacuum seal (set the handle of the vacuum valve to a vertical position or turn "away from you"), reduce engine speed to the minimum idle speed and turn off the gas-jet vacuum apparatus (with the corresponding control lever using a shutter in the distribution chamber, shut off the flow of exhaust gases into the jet pump).

The time for filling the fire pump with water at a geometric suction height of 7 m should be no more than 35 s. Vacuum (when checking the fire pump for tightness) within 73 ... 76 kPa should be achieved in a time of no more than 20 s.

The control system of the gas-jet vacuum apparatus can also have a manual or electro-pneumatic drive.

The manual drive of switching on (turning the damper) is carried out by lever 8 (see Fig. 5) from the pump compartment, connected through a system of rods 10 and 12 with the lever of the damper axis of the gas-jet vacuum apparatus. To ensure a tight fit of the damper to the seats of the distribution chamber of the gas-jet vacuum apparatus during the operation of the fire truck, it is necessary to periodically adjust the length of the rods using the appropriate adjusting units. The tightness of the damper in its vertical position (when the gas-jet vacuum apparatus is turned on) is assessed by the absence of exhaust gases passing through the muffler into the atmosphere (with the integrity of the damper itself and the serviceability of its drive).

Conclusion on the question:

Electric vane vacuum pump

Currently, vane vacuum pumps are installed in the vacuum systems of centrifugal fire pumps in order to improve technical and operational characteristics, incl. AVS-01E and AVS-02E.

In terms of its composition and functional characteristics, the AVS-01E vacuum pump is an autonomous vacuum system for water filling of a centrifugal fire pump. AVS-01E includes the following elements: vacuum unit 9, control unit (panel) 1 with electric cables, vacuum valve 4, vacuum valve control cable 2, filling sensor 6, two flexible air lines 3 and 10.

Rice. 4 Vacuum system set AVS-01E

The vacuum unit (see Fig. 4) is designed to create the vacuum required during water filling in the cavity of the fire pump and in the suction hoses. It is a vane-type vacuum pump 3 with an electric drive 10. The vacuum pump itself consists of a body part formed by a housing 16 with a sleeve 24 and covers 1 and 15, a rotor 23 with four blades 22, mounted on two ball bearings 18, a lubrication system (including an oil tank 26, tube 25 and nozzle 2) and two nozzles 20 and 21 for connecting air ducts.

How the vacuum pump works

The vacuum pump works as follows. When the rotor 23 rotates, the blades 22 under the action of centrifugal forces are pressed against the sleeve 24 and thus forms closed working cavities. The working cavities, due to the counterclockwise rotation of the rotor, move from the suction window communicating with the inlet branch pipe 20 to the outlet window communicating with the outlet branch pipe 21. When passing through the area of ​​the suction window, each working cavity captures a portion of air and moves it to the exhaust a window through which air is discharged into the atmosphere through an air duct. The movement of air from the suction port to the working cavities and from the working cavities to the exhaust port occurs due to pressure drops that are formed due to the presence of eccentricity between the rotor and the sleeve, leading to compression (expansion) of the volume of the working cavities.

The rubbing surfaces of the vacuum pump are lubricated by engine oil, which is supplied to its suction cavity from the oil tank 26 due to the vacuum created by the vacuum pump itself in the inlet pipe 20. The specified oil flow rate is provided by a calibrated hole in the nozzle 2. The electric drive of the vacuum pump consists of an electric motor 10 and traction relay 7. Electric motor 10, designed for 12 V DC. The rotor 11 of the electric motor is supported by one end on the sleeve 9, and the other end through the centering sleeve 12 bears on the protruding shaft of the rotor of the vacuum pump. Therefore, turning on the electric motor after disconnecting it from the vacuum pump is not allowed.

The torque from the engine to the rotor of the vacuum pump is transmitted through the pin 13 and the groove at the end of the rotor. The traction relay 7 provides commutation of the contacts of the power circuit "+12 V" when the electric motor is turned on, and also moves the core of the cable 2, leading to the opening of the vacuum valve 4, in systems where it is provided. The casing 5 protects the open contacts of the electric motor from accidental short circuit and from the ingress of water on them during operation.

The vacuum valve is designed to automatically shut off the cavity of the fire pump from the vacuum unit at the end of the water filling process and is installed in addition to the vacuum seal 5. 2, fixed on the rod 7, is connected to the cable core from the traction relay of the vacuum unit. In this case, the cable sheath is fixed by the bushing 4, which has a longitudinal groove for installing the cable. When the traction relay is turned on, the cable core pulls the rod 6 by the shackle 2, and the flow cavity of the vacuum valve opens. When the traction relay is turned off (i.e. when the vacuum unit is turned off), the rod 6, under the action of the spring 9, returns to its original (closed) position. With this position of the rod, the flow cavity of the vacuum valve remains closed, and the cavities of the centrifugal fire pump and the vane pump remain disconnected. To lubricate the friction surfaces of the valve, a lubricating ring 8 is provided, into which, during operation of the vacuum system, oil must be added through hole "A".

The filling sensor is designed to send signals to the control unit about the completion of the water filling process. The sensor is an electrode installed in an insulator at the top point of the inner cavity of a centrifugal fire pump. When the sensor is filled with water, the electrical resistance between the electrode and the body ("ground") changes. The change in the resistance of the sensor is recorded by the control unit, in which a signal is generated to turn off the electric motor of the vacuum unit. At the same time, the "Pump full" indicator on the control panel (block) turns on.

The control unit (panel) is designed to ensure the operation of the vacuum system in manual and automatic modes.

Toggle switch 1 "Power" serves to supply power to the control circuits of the vacuum unit and to activate the light indicators about the state of the vacuum system. Toggle switch 2 "Mode" is designed to change the operating mode of the system - automatic ("Auto") or manual ("Manual"). Button 8 "Start" is used to turn on the motor of the vacuum unit. Button 6 "Stop" is used to turn off the engine of the vacuum unit and to release the lock after the indicator "Not normal" comes on. Cables 4 and 5 are designed to connect the control unit, respectively, to the motor of the vacuum unit and the filling sensor. The remote control has the following indicator lights 7, which are used to visual control the state of the vacuum system:

1. The "Power" indicator lights up when you turn on toggle switch 1 "Power";

2. Vacuuming - signals the activation of the vacuum pump by pressing the button 8 "Start";

1. Pump full - lights up when the fill sensor is triggered, when the fire pump is completely filled with water;
2. Not normal - fixes the following malfunctions of the vacuum system:
   • the maximum time of continuous operation of the vacuum pump (45 ... 55 seconds) has been exceeded due to insufficient tightness of the suction line or fire pump;
   • poor or missing contact in the traction relay circuit of the vacuum unit due to burning of the relay contacts or broken wires;
   • the vacuum pump motor is overloaded due to clogged vane vacuum pump or other causes.

On the AVS-02E model and the latest AVS-01E models, the vacuum valve (item 4 in Fig. 3.28) is not installed.

The AVS-02E vacuum pump ensures the operation of the vacuum system only in manual mode.

Depending on the combination of the position of the "Power" and "Mode" toggle switches, the vacuum system can be in four possible states:

1. Out of service the "Power" toggle switch should be in the "Off" position, and the "Mode" toggle switch should be in the "Auto" position. This position of the toggle switches is the only one in which pressing the "Start" button does not turn on the electric motor of the vacuum unit. The indication is off.
2. In automatic mode(main mode) the "Power" toggle switch should be in the "On" position, and the "Mode" toggle switch should be in the "Auto" position. In this case, the electric motor is switched on by short-term pressing of the "Start" button. Disconnection is carried out either automatically (when the filling sensor or one of the types of protection of the electric drive is triggered), or forcibly - by pressing the "Stop" button. The indicator is on and reflects the state of the vacuum system.
3. In manual mode the "Power" toggle switch must be in the "On" position, and the "Mode" toggle switch must be in the "Manual" position. The engine is turned on by pressing the "Start" button and runs as long as the "Start" button is held down. In this mode, the electronic protection of the drive is disabled, and the readings of the light indicators only visually reflect only the process of water filling. Manual mode is designed to be able to work in case of failures in the automation system, in case of false alarms of interlocks. Control of the end of the process of water filling and shutdown of the vacuum pump motor in manual mode is carried out visually by the indicator "Pump full".
4. There is emergency mode, at which the "Power" toggle switch must be turned off, and the "Mode" toggle switch set to the "Manual" position. In this mode, the electric motor is controlled in the same way as in the manual mode, but the indication is turned off, and the control of the end of the water filling process and the shutdown of the vacuum pump motor is carried out upon the appearance of water from the exhaust pipe. Systematic work in this mode is unacceptable, because can lead to serious damage to the elements of the vacuum system. Therefore, immediately upon returning to the fire department, the cause of the control unit malfunction should be identified and eliminated.

Air ducts 3 and 10 (see Fig. 3.28) are designed, respectively, to connect the cavity of the centrifugal fire pump with the vacuum unit and to direct the exhaust from the vacuum unit.

Vane Pump Vacuum System Operation

The order of work of the vacuum system:

1. Checking the fire pump for leaks ("dry vacuum"):

a) prepare the fire pump for testing: install a plug on the suction pipe, close all taps and valves;

b) open the vacuum seal;

c) turn on the "Power" toggle switch on the control unit (console);

d) start the vacuum pump: in automatic mode, it is started by briefly pressing the "Start" button, in manual mode - the "Start" button must be pressed and held;

e) evacuate the fire pump to a vacuum level of 0.8 kgf / cm 2 (in the normal state of the vacuum pump, fire pump and its communications, this operation takes no more than 10 seconds);

f) stop the vacuum pump: in automatic mode, it is forced to stop by pressing the "Stop" button, in manual mode - release the "Start" button;

g) close the vacuum seal and, using a stopwatch, check the rate of the vacuum drop in the cavity of the fire pump;

h) turn off the "Power" toggle switch on the control unit (console), and set the "Mode" toggle switch to the "Auto" position.

1. Water intake in automatic mode:

b) open the vacuum seal;

c) set the "Mode" toggle switch to the "Auto" position and turn on the "Power" toggle switch;

d) start the vacuum pump - press and release the "Start" button: in this case, simultaneously with the activation of the drive of the vacuum unit, the "Vacuuming" indicator lights up;

e) after the end of water filling, the drive of the vacuum unit turns off automatically: the “Pump full” indicator lights up and the “Vacuuming” indicator goes out. In case of leakage of the fire pump, after 45 ... 55 seconds, the vacuum pump drive should be automatically turned off and the "Not normal" indicator will light up, after which it is necessary to press the "Stop" button;

g) turn off the "Power" toggle switch on the control unit (console).

As a result of failure of the filling sensor (this can happen, for example, when a wire breaks), the automatic shutdown of the vacuum pump does not work, and the "Pump full" indicator does not light up. This situation is critical because after filling the fire pump, the vacuum pump does not turn off and begins to "choke" with water. This mode is immediately detected by the characteristic sound caused by the release of water from the exhaust pipe. In this case, it is recommended, without waiting for the protection to operate, to close the vacuum seal and turn off the vacuum pump forcibly (using the "Stop" button), and at the end of the work, detect and eliminate the malfunction.

1. Manual water intake:

a) prepare the fire pump for water intake: close all valves and taps of the fire pump and its communications, connect the suction hoses with a mesh and immerse the end of the suction line into the reservoir;

b) open the vacuum seal;

c) set the "Mode" toggle switch to the "Manual" position and turn on the "Power" toggle switch;

d) start the vacuum pump - press the "Start" button and hold it down until the "Pump full" indicator lights up;

e) after the end of water filling (as soon as the indicator "Pump full" lights up), stop the vacuum pump - release the "Start" button;

f) close the vacuum seal and start working with the fire pump in accordance with the instructions for its operation;

g) turn off the "Power" toggle switch on the control unit (console), and set the "Mode" toggle switch to the "Auto" position.

In case of loss of pressure, it is necessary to stop the fire pump and repeat operations "c" - "e".

1. Features of work in winter:

a) After each use of the pumping unit, it is necessary to blow through the air lines of the vacuum pump, even in cases where the fire pump was supplied with water from a tank or hydrant (water may enter the vacuum pump, for example, through a loose or faulty vacuum seal). Purge should be performed by short-term (for 3 ÷ 5 seconds) turning on the vacuum pump. In this case, it is necessary to remove the plug from the suction pipe of the fire pump and open the vacuum seal.

b) Before starting work, check the vacuum valve for freezing of its moving part. To check, it is necessary to make sure that its rod is mobile by pulling on the shackle 2 (see Fig. 3.30), to which the cable core is attached. In the absence of freezing, the shackle together with the rod of the vacuum valve and the living cable should move from a force of about 3 ÷ 5 kgf.

c) To fill the oil tank of the vacuum pump, use winter brands of engine oils (with low viscosity).

Conclusion on the question: vane vacuum pumps are installed in vacuum systems of centrifugal fire pumps in order to improve technical and operational characteristics.

Maintenance

At Simultaneously with checking the fire pump for tightness, the operability of the gas-jet vacuum apparatus, the vacuum valve is checked and (if necessary) adjustment of the drive rods of the gas-jet vacuum apparatus is carried out.

TO-1 includes daily maintenance operations. In addition, if necessary, dismantling, complete disassembly, lubrication, replacement of worn parts and installation of a gas-jet vacuum apparatus and a vacuum valve are carried out. Graphite grease is used to lubricate the damper axis in the distribution chamber of the gas-jet vacuum apparatus.

At TO-2, in addition to TO-1 operations, the performance of the vacuum system is checked at special stands of the station (post) of technical diagnostics.

To ensure the constant technical readiness of the vacuum system, the following types are provided Maintenance: daily Maintenance(ETO) and first maintenance (TO-1). List of works and technical requirements for carrying out the specified types of maintenance are given in table.

List of works during maintenance vacuum system AVS-01E.

View Maintenance	Content of work	Technical requirements (methodology)
Daily Maintenance (ETO)	1. Checking the presence of oil in the oil tank.	1. Maintain the oil level in the reservoir at least 1/3 of its volume.
	2. Checking the performance of the vacuum pump and the functioning of the lubrication system of the vane pump.	2. Carry out the check in the test mode of the fire pump for tightness ("dry vacuum"). When the vacuum pump is turned on, the oil supply pipe must be completely filled with oil up to the nozzle.
First maintenance	1. Checking the tightening of fasteners.	1. Check the tightness of the fasteners of the components of the vacuum system.
	2. Lubrication of the rod and control cable of the vacuum valve.	2. Put a few drops of engine oil into hole A of the vacuum valve body. Disconnect the cable from the vacuum valve and drip a few drops of engine oil into the cable.
	3. Checking the axial play of the sheath of the vacuum valve control cable at the point of its connection with the traction relay of the vacuum pump electric drive.	3. Axial play is allowed no more than 0.5 mm. Determine the play by moving the cable sheath back and forth. In case of discrepancy, exclude backlash.
	4. Checking the correct position of the shackle 2 of the vacuum valve.	4. Check the clearances: - Gap "B" - when the electric drive is not working; - Gap "B" - when the electric drive is running. The dimensions of the gaps "B" and "C" must be at least 1 mm. The clearances should be adjusted if necessary. To adjust, disconnect the cable from the vacuum valve, loosen the lock nut and set the required shackle position; Tighten the lock nut.
	5. Checking oil consumption.	5. Average oil consumption for a cycle of 30 sec. should be at least 2 ml.
	6. Cleaning the working surfaces of the filling sensor.	6. Unscrew the sensor from the housing, clean the electrode and the visible part of the body surface to the base metal.

Conclusion on the question: maintenance is necessary to maintain the vacuum systems in working order.

Malfunctions of vacuum systems

When operating a vacuum system as part of a pumping unit, the following malfunction of the vacuum system is most typical: the pump is not filled with water (or the required vacuum is not created) when the vacuum system is on. This malfunction, with a serviceable fire engine engine, can be caused by the following reasons:

1. The exhaust gas outlet through the muffler to the atmosphere is not completely blocked by the damper. The reasons may be the presence of carbon deposits on the damper and in the HVA body, violation of the adjustment of the thrust drive of its control, wear of the damper axis.
2. The diffuser or nozzle of the vacuum jet pump is clogged.
3. There are leaks in the connections between the vacuum valve and the fire pump, the piping of the vacuum system or cracks in it.
4. There are deformations or cracks in the HVA hull.
5. There are leaks in the exhaust tract of the fire engine engine (usually occur due to burnout of the exhaust pipes).
6. Clogged piping of the vacuum system or freezing of water in it.

Possible malfunctions of the AVS-01E vacuum systemand methods of their elimination

Refusal name, its external signs	Probable cause	Elimination method
When you turn on the "Power" toggle switch, the "Power" indicator does not light up.	Control box fuse blown.	Replace fuse.
	Open in the power supply circuit of the control unit.	Eliminate the break.
When operating in automatic mode, after water intake, the vacuum pump does not automatically turn off.	Open circuit from the electrode or from the filling sensor housing.	Repair the open circuit.
	Reducing the conductivity of the surface of the housing and the electrode of the filling sensor	Remove the filling sensor and clean the electrode and the surface of its body from contamination.
	Insufficient supply voltage at the control unit.	Check the reliability of contacts in electrical connections; ensure the supply voltage of the control unit is at least 10 V.
In automatic mode, the vacuum pump starts, but after 1-2 seconds. stops; the "Vacuuming" indicator goes out and the "Not normal" indicator comes on. In manual mode, the pump operates normally.	Loose contact in the connecting cables between the control unit and the electric drive of the vacuum pump.	Check the reliability of the contacts in the electrical connections.
	The tips of the wires on the contact bolts of the traction relay are oxidized or the nuts of their fastening are loosened.	Clean the tips and tighten the nuts.
	A large (more than 0.5 V) voltage drop between the contact bolts of the traction relay when the electric motor is running.	Remove the traction relay, check the ease of movement of the armature. If the armature mixes freely, then clean the relay contacts or replace it.
The vacuum pump does not start automatically or manually. After 1-2 sec. after pressing the "Start" button, the "Vacuuming" indicator goes out and the "Not normal" indicator lights up	It is difficult to move the core of the vacuum valve control cable.	Check the ease of movement of the cable core, if necessary, eliminate a strong bend in the cable or lubricate its core with engine oil.
	The movement of the vacuum valve stem is difficult.	Lubricate the valve through hole A. In winter, take measures to prevent the parts of the vacuum valve from freezing.
	Breakage of the power supply circuit	Repair the open circuit.
	The position of the shackle of the vacuum valve is violated.	Adjust the position of the earring.
	Breakage of electrical circuits in the cable connecting the control unit with the electric drive of the vacuum unit.	Repair the open circuit.
	The contacts of the traction relay are burnt out.	Clean the contacts or replace the traction relay.
	The electric motor is overloaded (the vane pump is inhibited by frozen water or foreign objects).	Check the condition of the vane pump. In winter, take measures to prevent mutual freezing of the vane pump parts.
When the vacuum pump is operating, it is noted that the oil consumption is too low (on average less than 1 ml per cycle)	Lubricating oil is of the wrong grade or is too viscous.	Replace with all-season engine oil according to GOST 10541.
	The metering hole of the nozzle 2 in the oil line is clogged.	Clean the metering hole of the oil line.
	Air is leaking through the oil line joints.	Tighten the oil line clamps.
When the vacuum pump is operating, the required vacuum is not provided	Air leaks in the suction hoses, through unclosed valves, drain taps, through damaged air ducts.	Ensure the tightness of the vacuum volume.
	Air leaks through the oil tank (with no oil at all).	Fill oil tank.
	Insufficient supply voltage of the electric drive of the vacuum unit.	Strip contacts of power cables, pole terminals battery; grease them with petroleum jelly and tighten securely. Charge the battery
	Insufficient lubrication of the vane pump.	Check oil consumption.

Conclusion on the question: Knowing the device and possible malfunctions vacuum systems, the driver can quickly find and fix the problem.

Lesson conclusion: The vacuum system of a centrifugal fire pump is designed to pre-fill the suction line and pump with water when water is taken from an open water source (reservoir), in addition, using a vacuum system, a vacuum (vacuum) can be created in the centrifugal fire pump housing to check the tightness of the fire pump.

Fire protection systems

A fire on a ship is an extremely serious hazard. In many cases, a fire causes not only significant material losses, but also causes the death of people. Therefore, the prevention of fires on ships and fire-fighting measures are of paramount importance.

To localize a fire, the vessel is divided into vertical fire zones by fire-resistant bulkheads (type A), which remain impervious to smoke and flame for 60 minutes. The fire resistance of the bulkhead is ensured by insulation made of non-combustible materials. Fire-resistant bulkheads on passenger ships are installed at a distance of no more than 40 m from each other. The same bulkheads are used to shield control posts and premises that are dangerous in terms of fire.

Inside the fire zones, the premises are separated by fire-retaining bulkheads (type B), which remain impervious to flame for 30 minutes. These structures are also insulated with fire-resistant materials.

All openings in fire bulkheads shall be provided with closures to ensure smoke and flame tightness. For this purpose, fire doors are insulated from non-combustible materials or water curtains are installed on each side of the door. All fire doors are equipped with a device for remote closing from the control room

The success of fire fighting depends to a large extent on the timely detection of the fire source. For this purpose, ships are equipped with various signaling systems to detect a fire at its very beginning. There are many types of signaling systems, but they all work on the principle of detection: temperature rise, smoke and open flames.

In the first case, temperature-sensitive detectors are installed in the premises, connected to the signal electrical network. When the temperature rises, the detector is triggered and closes the network, as a result, a warning lamp on the navigating bridge lights up and an audible alarm is triggered. Signaling systems based on detection work in the same way. open flame... In this case, photocells are used as detectors. The disadvantage of these systems is some delay in fire detection, since the start of a fire is not always accompanied by an increase in temperature and the appearance of an open flame.

Smoke detection systems are more sensitive. In these systems, air from the controlled rooms is constantly sucked by the fan through the signal pipes. By the smoke coming out of a certain pipe, it is possible to determine the room in which a fire has occurred

Smoke detection is carried out by sensitive photocells, which are installed at the ends of the pipes. When smoke appears, the light intensity changes, as a result of which the photocell is triggered and closes the light and sound alarm network.

The means of active fire fighting on the ship are various fire extinguishing systems: water, steam and gas, as well as volumetric chemical extinguishing and foam extinguishing.

Water extinguishing system. The most common means of fighting ship fires is a water-based fire extinguishing system, which should be fitted to all ships.
The system is based on a centralized principle with a linear or ring main pipeline, which is made of galvanized steel pipes with a diameter of 100-200 mm. Fire horns (taps) are installed along the entire highway to connect fire hoses. The location of the horns should ensure the supply of two jets of water to any place on the vessel. In indoor areas they are installed no more than 20 m apart, and on open decks this distance is increased to 40 m. In order to be able to quickly locate the fire pipeline, it is painted red. In cases where the pipeline is painted in the color of the room, two narrow distinctive green rings are applied to it, between which a narrow red warning ring is painted. Fire horns are painted red in all cases.

The water extinguishing system uses centrifugal pumps with a drive independent of the main engine. Stationary fire pumps are installed below the waterline to provide suction head. If pumps are installed above the waterline, they must be self-priming. The total number of fire pumps depends on the size of the vessel and on large vessels reaches three with a total flow of up to 200 m3 / h. In addition to these, many ships have an emergency pump driven by an emergency power source. For fire-fighting purposes, ballast, bilge and other pumps can also be used, if they do not serve for pumping oil products or for draining compartments in which residues of oil products may be.

On ships with a gross tonnage of 1000 reg. t and more on an open deck on each side of the water-fire main must have a device for connecting an international connection.
The effectiveness of a water suppression system is highly dependent on pressure. The minimum pressure at the location of any fire horn is 0.25-0.30 MPa, which gives the height of the water jet from the fire hose to 20-25 m 6-0.7 MPa. The water extinguishing pipeline is designed for a maximum pressure of up to 10 MPa.

The water extinguishing system is the simplest and most reliable, but it is not possible to use a continuous stream of water to extinguish a fire in all cases. For example, when extinguishing burning oil products, it has no effect, since oil products float to the surface of the water and continue to burn. The effect can only be achieved if the water is sprayed. In this case, the water quickly evaporates, forming a steam-water hood that isolates the burning oil from the surrounding air.

On ships, sprayed water is supplied by a sprinkler system, which can be equipped with residential and public premises, as well as a wheelhouse and various storerooms. On the pipelines of this system, which are laid under the ceiling of the protected room, automatically operating sprinkler heads are installed (Fig. 143).

Fig. 143. Sprinkler heads-a - with a metal lock, b - with a glass flask, 1- fitting, 2- glass valve, 3- diaphragm, 4- ring; 5- washer, 6- frame, 7- socket; 8- low-melting metal lock, 9- glass flask

The outlet of the sprinkler is closed by a glass valve (ball), which is supported by three plates, interconnected by low-melting solder. When the temperature rises during a fire, the solder melts, the valve opens, and the outgoing stream of water, hitting a special socket, is sprayed. For other types of sprinklers, the valve is held in place by a glass bulb filled with a highly volatile liquid. In the event of a fire, liquid vapors rupture the flask, as a result of which the valve opens.

The opening temperature of sprinklers for residential and public premises, depending on the navigation area, is taken at 70-80 ° C.

To provide automatic operation the sprinkler system must always be under pressure. The required pressure is created by the pneumatic tank, which the system is equipped with. When the sprinkler is opened, the pressure in the system drops, as a result of which the sprinkler pump is automatically turned on, which provides the system with water when extinguishing a fire. In emergency cases, the sprinkler pipeline can be connected to the water suppression system.

In the engine room, a water-spraying system is used to extinguish oil products. On the pipelines of this system, instead of automatically operating sprinkler heads, water nozzles are installed, the outlet of which is constantly open. The spray nozzles take effect as soon as the shut-off valve on the supply line is opened.

The sprayed water is also used in irrigation systems and to create water curtains. The irrigation system is used to irrigate the decks of oil tankers and bulkheads of rooms intended for the storage of explosive and flammable substances.

Water curtains act as fire bulkheads. Such curtains are used to equip closed decks of ferries with a horizontal loading method, where it is impossible to install bulkheads. Fire doors can also be replaced with water curtains.

The most promising is the system of finely sprayed water, in which water is sprayed to a foggy state. Water spraying is carried out through spherical nozzles with big amount holes with a diameter of 1 - 3 mm. For better atomization, compressed air and a special emulsifier are added to the water.

Steam suppression system. The operation of the steam fire extinguishing system is based on the principle of creating an atmosphere in the room that does not support combustion. Therefore, steam extinguishing is used only in closed rooms. Since there are no large-capacity boilers on modern ships with internal combustion engines, only fuel tanks are usually equipped with a steam extinguishing system. Steam extinguishing can also be used in. engine mufflers and chimneys.

The steam extinguishing system on ships is carried out according to a centralized principle. From the steam boiler, steam with a pressure of 0.6-0.8 MPa enters the steam distribution box (collector), from where separate pipelines from steel pipes with a diameter of 20-40 mm. In rooms with liquid fuel, steam is supplied to the upper part, which provides a free escape of steam when the tank is filled to the maximum. On the pipes of the steam extinguishing system, two narrow distinctive rings of silver-gray color with a red warning ring between them are painted.

Gas systems. The principle of operation of the gas system is based on the fact that an inert gas that does not support combustion is supplied to the place of fire. Working on the same principle as the steam extinguishing system, the gas system has a number of advantages over it. The use of non-conductive gas in the system makes it possible to use the gas system to stop a fire on operating electrical equipment. When using the system, gas does not damage cargo and equipment.

Of all the gas systems on ships, carbon dioxide is widely used. Liquid carbon dioxide is stored on ships in special pressurized cylinders. The cylinders are connected into batteries and work on a common junction box, from which pipelines from steel seamless galvanized pipes with a diameter of 20-25 mm are led to separate rooms. One narrow distinctive ring is painted on the pipeline of the carbon dioxide system yellow color and two warning signs, one red and the other yellow with black diagonal stripes. Pipes are usually laid below deck without downward slopes, since carbon dioxide is heavier than air and must be injected into the upper part of the room when extinguishing a fire. Carbon dioxide is released from the outgrowths through special nozzles, nozzles, the amount of which in each room depends on the volume of the room. This system has a control device.

The carbon dioxide system can be used to extinguish fires in enclosed spaces. Most often, such a system is equipped with dry cargo holds, engine-boiler rooms, electrical equipment rooms, as well as storerooms with combustible materials. The use of a carbon dioxide system in cargo tanks of tankers is not allowed. It should also not be used in residential and public areas, since even a slight gas leak can lead to accidents.

While it has certain advantages, the carbon dioxide system is not without its disadvantages. The main ones are the one-time operation of the system and the need to thoroughly ventilate the room after using carbon dioxide extinguishing.

Along with stationary carbon dioxide installations, hand-held carbon dioxide fire extinguishers with liquid carbon dioxide cylinders are used on ships.

Bulk chemical extinguishing system. It works on the same principle as gas, but instead of gas, a special liquid is supplied to the room, which, easily evaporating, turns into an inert gas heavier than air.

A mixture containing 73% ethyl bromide and 27% tetrafluorodibromoethane is used as a fire-extinguishing liquid on ships. Other mixtures are sometimes used, such as ethyl bromide and carbon dioxide.

The extinguishing liquid is stored in a durable steel tanks, from which a highway is drawn to each of the protected premises. An annular pipeline with spray heads is laid in the upper part of the protected area. The pressure in the system is created by compressed air, which is supplied to the reservoir with liquid from cylinders.

The absence of mechanisms in the system allows it to be carried out both on a centralized basis and on a group or individual basis.

The volumetric chemical extinguishing system can be used in dry cargo and refrigerated holds, in the engine room and in rooms with electrical equipment.

Powder extinguishing system.

In this system, special powders are used, which are supplied to the place of ignition with a gas jet from a cylinder (usually nitrogen or another inert gas). Most often, powder fire extinguishers work on this principle. Gas carriers sometimes install this system for use in cargo compartments. Such a system consists of a powder extinguishing station, hand barrels and special non-twisting sleeves.

Foam extinguishing system. The principle of operation of the system is based on the isolation of the fire center from atmospheric oxygen by covering the burning objects with a layer of foam. Foam can be obtained either chemically as a result of the reaction of an acid and an alkali, or mechanically by mixing an aqueous solution of a foaming agent with air. Accordingly, the foam extinguishing system is divided into air-mechanical and chemical.

In the system of air-mechanical foam extinguishing (Fig. 144), to obtain foam, liquid foaming agent PO-1 or PO-b is used, which is stored in special tanks. When using the system, the foaming agent from the tank is fed by the ejector into the pressure pipeline, where it mixes with water, forming a water emulsion. There is an air-foam barrel at the end of the pipeline. The water emulsion, passing through it, sucks in air, as a result of which foam is formed, which is supplied to the place of the fire.

To obtain foam by air-mechanical method, the water emulsion must contain 4% foaming agent and 96% water. When the emulsion is mixed with air, a foam is formed, the volume of which is approximately 10 times the volume of the emulsion. To increase the amount of foam, special air-foam barrels with sprays and nets are used. In this case, a foam with a high foaming ratio (up to 1000) is obtained. A thousand-fold foam is obtained on the basis of the Morpen foam concentrate.

Rice. 144. Air-mechanical foam extinguishing system: 1- buffer liquid, 2- diffuser, 3- ejector-mixer, 4- manual air-foam barrel, 5- stationary air-foam barrel

Fig. 145 Local air-foam installation 1- siphon tube, 2- tank with emulsion, 3- air inlets, 4- shut-off valve, 5- neck, 6- pressure reducing valve, 7- foam line, 8- flexible hose, 9- shower, 10 - compressed air cylinder; 11-pipeline of compressed air, 12- three-way valve

Along with stationary foam extinguishing systems on ships, local air-foam installations are widely used (Fig. 145). In these installations, which are located directly in the protected premises, the emulsion is in a closed tank. To start the installation, compressed air is supplied to the tank, which displaces the emulsion into the pipeline through a siphon tube. Part of the air flows into the same pipeline through the hole in the upper part of the siphon tube. As a result, the emulsion mixes with air in the pipeline and foam forms. The same installations of small capacity can be carried out with a portable - air-foam fire extinguisher.

When foam is produced chemically, carbon dioxide is contained in its bubbles, which increases its extinguishing properties. Chemically foam is obtained in hand-held foam fire extinguishers of the OP type, consisting of a tank filled with an aqueous solution of soda and acid. By turning the handle, the valve is opened, the alkali and acid are mixed, as a result of which foam is formed, which is ejected from the spray.

The foam extinguishing system can be used to extinguish a fire in any premises, as well as on an open deck. But it received the greatest distribution on oil tankers. Typically, tankers have two foam extinguishing stations: the main one at the stern and the emergency one in the tank superstructure. A main pipeline is laid between the stations along the ship, from which a branch with an air-foam barrel extends into each cargo tank. From the barrel, the foam goes into the perforated foam drain pipes located in the tanks. All foam pipes have two wide distinctive green rings with a red warning sign between them. To extinguish a fire on open decks, oil tankers are equipped with air-foam monitors, which are installed on the deck of superstructures. The monitors give a jet of foam over 40 m long, which allows, if necessary, to cover the entire deck with foam.

To ensure the fire safety of the vessel, all fire extinguishing systems must be in good condition and always ready for action. The system status is checked by regular inspections and training fire alarms. During inspections, it is necessary to carefully check the tightness of the pipelines and good work fire pumps. In winter, fire lines can freeze. To prevent freezing, it is necessary to turn off the sections laid on open decks and drain the water through special plugs (or taps).

The carbon dioxide system and the foam extinguishing system require especially careful maintenance. If the valves installed on the cylinders are in a malfunctioning state, gas leakage is possible. To check the presence of carbon dioxide, the cylinders should be weighed at least once a year.

All malfunctions revealed during inspections and training alarms must be immediately eliminated. It is prohibited to set sailing vessels if:

At least one of the stationary fire extinguishing systems is faulty; system fire alarm does not work;

The compartments of the ship, protected by the volumetric fire extinguishing system, do not have devices for closing the premises from the outside;

Fire bulkheads have faulty insulation or faulty fire doors;

The fire-fighting equipment of the vessel does not correspond to the established standards.

Chapter 12 - Stationary Emergency Fire Pumps

1 Application

This chapter sets out the specifications for emergency fire pumps required by chapter II-2 of the Convention. This chapter does not apply to passenger ships of 1,000 gross tonnage and over. For requirements for such ships, see regulation II-2 / 10.2.2.3.1.1 of the Convention.

2 Technical specifications

2.1 General

The emergency fire pump must be a stationary pump with an independent drive.

2.2 Component requirements

2.2.1 Emergency fire pumps

2.2.1.1 Pump flow

The pump flow must be at least 40% of the total fire pump flow required by regulation II-2 / 10.2.2.4.1 of the Convention, and in any case not less than the following:

2.2.1.2 Pressure at valves

If the pump delivers the amount of water required by paragraph 2.2.1.1, the pressure at any tap must be at least the minimum pressure required by chapter II-2 of the Convention.

2.2.1.3 Suction heights

For all heel, pitch, roll and pitch conditions that may occur during operation, the total suction lift and net positive lift of the pump shall be determined taking into account the requirements of the Convention and this chapter for pump flow and valve pressure. A vessel in ballast when entering or exiting drydock may not be considered to be in service.

2.2.2 Diesel Engines and Fuel Tank

2.2.2.1 Starting a diesel engine

Any diesel driven power source that feeds the pump must be able to be easily started manually from a cold state down to 0 ° C. If this is impracticable, or if lower temperatures are anticipated, consideration should be given to the installation and operation of rapid start-up heating facilities acceptable to the Administration. If manual starting is impracticable, the Administration may authorize the use of other means of starting. These means must be such that the diesel-powered power source can be started at least six times in 30 minutes and at least twice in the first 10 minutes.

2.2.2.2 Fuel tank capacity

Any service fuel tank must contain sufficient fuel to operate the pump at full load for at least 3 hours; Outside a category A machinery space, there must be sufficient fuel to keep the pump running at full load for an additional 15 hours.

Parallelograms of speeds on the impellers

When entering the blade and leaving the blade, each liquid particle acquires, respectively:

1. Peripheral speeds U 1 and U 2 directed tangentially to the input and
the output circumference of the impeller.

2. Relative speeds W 1 and W 2 directed tangentially to the surface of the blade profile.

3. The absolute velocities C 1 and C 2, obtained as a result of the geometric addition of U1,

Since the pump is a mechanism that converts the mechanical energy of the drive into energy (head), imparting the movement of the fluid in the space between the blades of the wheel, its theoretical value (head) obtained during the operation of the pump can be determined by the Euler formula:

C 2 U 2 cos α 2 - C 1 U 1 cos α 1

H t ∞ = __________________________

In view of the fact that the centrifugal pump does not have a guide vane when the liquid enters the blades, in order to avoid large hydraulic losses from the impacts of the liquid on the blades, and to reduce the pressure losses, the liquid inlet to the wheel is made radial (the direction of the absolute speed С 1 is radial). In this case, α 1 = 90, then cos 90 - 0, therefore, the product C 1 U 1 cos α 1 = 0. Thus, the basic equation for the head of a centrifugal pump, or Euler's equation, will take the form:

Н t ∞ = C 2 U 2 cos α 2 / g

In a real pump there is a finite number of blades and head losses due to vortices of fluid particles are taken into account by the coefficient φ (phi), and hydraulic resistances are taken into account by hydraulic efficiency - ηg, then the actual head will take the form: Нд = Нt φηг

Taking into account all losses, the efficiency of the centrifugal pump is ηн 0.46-0.80.

Under operating conditions, the head of a centrifugal pump is determined by an empirical formula and depends on the number of revolutions of the drive motor and the diameter of the impeller:

Нн = к "* n 2 * D 2,

where: k "- experimental dimensionless coefficient

n - impeller rotation speed, rpm.

D is the outer diameter of the wheel, m.

The flow rate of the pump hp -1 is roughly determined by the diameter n of the discharge pipe:

Qн = k "d 2

where: k "- for a branch pipe diameter up to 100 mm - 13-48, more than 100 mm - 20-25

d is the diameter of the discharge pipe in dm.

2. To ensure the normal and safe operation of the vessel, as well as to create appropriate conditions for the stay of people on it, ship systems are used.
The ship system is understood as a network of pipelines with mechanisms, apparatus and instruments that perform certain functions on the ship. With the help of ship systems, the following are carried out: reception and removal of ballast water, fighting fires, draining the compartments of the ship from water accumulating in them, supplying passengers and crew with drinking and washing water, removing sewage and contaminated water, maintaining the necessary parameters (conditions) of air in the premises. Some ships, such as tankers, icebreakers, refrigerators, etc., are equipped with special systems due to specific operating conditions. So, tankers are equipped with systems designed for receiving and pumping out liquid cargo, heating it in order to facilitate pumping, washing tanks and cleaning them from oil residues. The large number of functions performed by ship systems determine the variety of their design forms and the mechanical equipment used. The ship systems include: pipelines consisting of interconnected individual pipes and fittings (valves, valves, taps), which are used to turn on or off the system and its sections, as well as for various adjustments and switching; mechanisms (pumps, fans, compressors) that impart mechanical energy to the medium flowing through them and ensure the movement of the latter through pipelines; vessels (tanks, cylinders, etc.) for storing a particular medium; various devices (heaters, coolers, evaporators, etc.), used to change the state of the environment; system management and monitoring tools.
Of the listed mechanisms and devices in each given ship system, there may be only a few of them. It depends on the purpose of the system and the nature of the functions it performs.
In addition to general ship systems, the ship has systems that serve the ship's power plant. On diesel vessels, these systems supply the main and auxiliary engines with fuel, oil, cooling water and compressed air. Ship power plant systems are discussed in the course on these plants.

3. Modern marine vessels are the place of permanent work and residence of crew members and long-term stay of passengers. Therefore, in the residential, service, passenger and public premises of these ships in any navigation areas, at any time of the year and under any meteorological conditions, a microclimate favorable for people should be maintained, i.e., the combination of the composition and parameters of the state of air, as well as thermal radiation in limited spaces of premises. The microclimate in the ship's rooms is ensured with the help of comfortable air conditioning systems and appropriate insulation of the rooms, the temperature of the inner surface of which should not differ significantly (more than 2 ° C) from the air temperature in these rooms.

Marine refrigeration unit.
1 - compressor; 2 - capacitor; 3 - expansion valve; 4 - evaporator; 5 - fan; o - refrigerator chamber; 7 - room of the evaporation plant.

Comfort air conditioning systems are intended for cleaning and heat-and-humidity treatment of air supplied to the premises. In this case, the room must be provided with certain, predetermined conditions, that is, the parameters of the composition and condition of the air: its purity, a sufficient percentage of oxygen content, temperature, relative humidity and mobility (speed of movement). These preset air conditions determine the so-called comfortable conditions for people.

In various areas of navigation of ships in different time year, the temperature of the outside (atmospheric) air can reach the highest (up to 40-45 ° C) and lowest (up to -50 ° C) values. In this case, the seawater temperature can vary over a wide range: from + 35 ° C to -2 ° C, and the moisture content in 1 kg of air is from 24-26 to 0.1-0.5 g. the intensity of solar radiation also changes. Considering that ships are large metal structures with a high coefficient of thermal conductivity, it becomes clear how great the influence of external conditions on the formation of the microclimate in ship premises is. In addition, there are a lot of internal objects of heat and moisture on the ship.

All this requires great flexibility (maneuverability) from the ship's comfort air conditioning system. In warm areas (or in summer), it should ensure the removal of the corresponding excess heat and moisture from the premises, and in cold areas (or in winter) it should compensate for heat losses and remove excess moisture, emitted mainly by people, as well as some equipment. In the summer season, the outside air usually needs to be cooled and dehumidified before being supplied to the premises, and in the winter it must be heated and humidified (although the outside air in the winter has a high relative humidity- up to 80-90%, it contains a very small amount of moisture, no more than 1-3 g per 1 kg of air).

Air heating and humidification carried out, as a rule, with steam or water, and its cooling and dehumidification - with the help of refrigerating machines. Thus, refrigeration machines are an integral part of marine comfort air conditioning systems (hereinafter, we will omit the word “comfortable” for brevity).

In addition, refrigeration machines are used on almost all ships of the sea and river fleet to preserve the stock of provisions, as well as on fishing, industrial and transport refrigerated vessels for handling and storing perishable goods (this function of refrigerators is commonly called refrigeration). In recent years, refrigeration machines began to be used to dry air in the holds of dry cargo and oil tankers. This prevents damage to hygroscopic cargo (flour, grain, cotton, tobacco, etc.), damage to equipment and machinery transported on board, and significantly reduces corrosion of internal metal parts of the hull and equipment of ships. This air handling in holds and tanks is commonly referred to as technical conditioning.

The first experience of using "machine" cooling on ships dates back to the 70s and 80s of the last century, when steam compressor ammonia, carbon dioxide and sulfur dioxide, air and absorption refrigeration machines were created and began to spread almost simultaneously. For example, in 1876, the French engineer-inventor Charles Tellier successfully used "machine" cold for the first time on the Frigori-fiq steamer to transport chilled meat from Buenos Aires to Rouen. In 1877 the steamboat "Paraguay", equipped with an absorption refrigeration unit, delivered frozen meat from South America to Le Havre, and the meat was frozen on the same ship in special chambers. This was followed by successful flights with meat from Australia to England, in particular on the steamer "Strathleven", equipped with an air refrigeration machine... By 1930, the world sea refrigerated fleet already consisted of 1,100 vessels with a total cargo capacity of 1.5 million conventional tons.

Fire Pumps

They are used as fire safety installations on tankers transporting liquefied natural gas, as well as on tankers converted for storage in oil field areas and for production facilities Manufacturer Ellehammer

As a rule, they are used as backup systems that duplicate ring fire extinguishing systems, when 3-4 emergency fire pumps do not allow the water pressure to drop in case of failure of the main system.

Emergency fire pumps equipped with electric or diesel engines... The range of such pumps is very large: from pumps with a 4-cylinder engine, developing 120 hp, which pump 70 m3 per hour - to huge units with a 12-cylinder engine, with a capacity of 38 liters, developing 1400 hp. which are capable of pumping over 2000 m3 per hour at a pressure of 12 bar.

Fire pumps and their kingstons must be located on the ship in heated

rooms below the waterline, the pumps must have independent drives and the flow of each stationary pump must be at least 80 % total flow divided by the number of pumps in the system, but not less 25 m3 / h. Fire fighting pumps should not be used to drain compartments containing petroleum products or residues of other flammable liquids.

A stationary fire pump can be used on a ship and for other purposes if the other pump is in constant readiness for immediate action to extinguish the fire
Total flow of stationary pumps should be increased if they serve other fire extinguishing systems simultaneously with the fire system. When determining this flow, the pressure in the systems must be taken into account. If the pressure in the connected systems is higher than in fire system, the pump flow must be increased due to the increase in flow through the fire nozzles with increasing pressure.
Stationary emergency fire pump is provided with everything necessary for operation (energy sources for its drive, receiving kingston) in case of failure of the main pumps and is connected to the ship's system. If necessary, it is provided with a self-priming device.

Emergency pumps are located in separate rooms, and emergency diesel-driven pumps are provided with fuel for 18 h work. Innings emergency pump should be sufficient to operate two barrels with largest diameter nozzles accepted for this vessel, and not less 40% total pump flow, but not less 25 m3 / h.

24 "Bulkhead Deck" is the uppermost deck to which transverse watertight bulkheads are extended.

25 "Deadweight" is the difference (in tonnes) between the ship's displacement in water with a density of 1.025 at the cargo waterline corresponding to the designated summer freeboard and the ship's light displacement.

26 "Empty displacement" is the displacement of a vessel (in tons) without cargo, fuel, lubricating oil, ballast, fresh and boiler water in tanks, ship's stores, as well as without passengers, crew and their property.

27 "Combined vessel" is a tanker designed for the carriage of oil in bulk or dry cargo in bulk.

28 "Crude oil" is any oil that occurs naturally in the earth's interior, whether or not it has been processed to facilitate its transportation, including:

1 crude oil from which some of the distillation cuts may have been removed; and

2 crude oil to which some of the distillation fractions may have been added.

29 "Dangerous goods" is the goods referred to in regulation VII / 2.

30 "Chemical tanker" is a tanker built or adapted and used for the carriage in bulk of any liquid flammable product specified:

1 in chapter 17 of the International Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bulk, hereinafter referred to as the International Bulk Chemical Code, adopted by resolution MSC.4 (48) of the Maritime Safety Committee, as amended by the Organization; or

2 chapter VI of the Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bulk, hereinafter referred to as the Bulk Chemical Code, adopted by resolution A.212 (VII) of the Assembly of the Organization, as amended by the Organization

whichever is applicable.

31 "Gas carrier" is a tanker built or adapted and used for the carriage in bulk of any liquefied gas or other flammable products specified:

1 in chapter 19 of the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk, hereinafter referred to as the International Gas Carrier Code, adopted by resolution MSC.5 (48) of the Maritime Safety Committee, as amended by the Organization; or

2 in chapter XIX of the Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk, hereinafter referred to as the Gas Carrier Code, adopted by resolution A.328DC) of the Assembly of the Organization, as amended by the Organization as applicable.

32 "Cargo area" is the part of the ship containing cargo tanks, drain tanks and cargo pump rooms, including pump rooms, cofferdams, ballast rooms and empty spaces adjacent to cargo tanks, as well as deck areas along the entire length and breadth of the ship above the mentioned premises.

33 For ships constructed on or after 1 October 1994, instead of the definition of main vertical zones in paragraph 9, the following definition applies:

main vertical zones are zones into which the hull, superstructure and deckhouses of the ship are divided by class "A" ceilings, average length and the width of which on any deck does not generally exceed 40 m, "

34 "Ro-ro passenger ship" is a passenger ship with horizontal loading and unloading cargo spaces or special category spaces as defined in this regulation.

34 Code of Fire Test Procedures means the International Code for the Application of Fire Test Procedures, adopted by the Organization's Maritime Safety Committee by resolution MSC.61 (67). as amended by the organization, provided that such amendments are accepted, enter into force and operate in accordance with the provisions of Article VIII of this Convention concerning the amendment procedures applicable to the Annex, with the exception of chapter I.

Rule 4

Fire pumps, fire lines, cranes and hoses

(Paragraphs 3.3.2.5 and 7.1 of this regulation apply to ships constructed on or after 1 February 1992)

1 Each ship should be provided with fire pumps, fire lines, taps and hoses, complying, as far as applicable, with the requirements of this regulation.

2 Performance of fire pumps

2.1 The required fire pumps shall provide a supply of water for fire fighting under the pressure specified in paragraph 4 in the following quantity:

1 pumps on passenger ships - not less than two-thirds of the quantity that is provided by bilge pumps when pumping water from holds; and

2 pumps on cargo ships, other than any emergency pump, not less than four thirds of the number which each independent bilge pump provides under regulation II-1/21 when pumping water from holds on a passenger ship of the same size; however, it is not necessary for the total required capacity of the fire pumps on any cargo ship to exceed 180 m3 / h.

2.2 The capacity of each of the required fire pumps (other than any emergency pump required by clause 3.3.2 for cargo ships) must be at least 80% of the total required capacity divided by the minimum number of fire pumps required, but in any case not less than 25 m ^ 3 / h each such pump must in any case provide at least two jets of water. These fire pumps must supply water to the fire main under the required conditions. If the number of pumps installed exceeds the required minimum number, the capacity of the additional pumps should be to the satisfaction of the Administration.

3 Measures related to fire pumps and fire lines

3.1 On ships, fire pumps with independent drives should be provided in the following number:

		passenger			at least 3
			capacity
	4000 reg.t and more
		passenger			at least 2
			capacity
	less than 4000 reg.t and for
	freight
	with a capacity of 1000 reg.t and
	on cargo ships gross				in accordance with the requirements
	with a capacity of less than 1000				Administration

3.2 Sanitary, ballast, and bilge pumps or general purpose pumps may be considered fire pumps provided that they are not normally used to transfer fuel, and if they are sometimes used to transfer or transfer fuel, appropriate switching devices must be provided.

3.3 The location of the receiving kingstons, fire pumps and their energy sources should be such that:

1 on passenger ships of 1,000 gross tonnage and above, a fire in any compartment could not disable all fire pumps;

2 in cargo ships of 2,000 gross tonnage and above, if a fire in any of the compartments could disable all pumps, another means was available, consisting of a stationary, independently driven emergency pump that should provide two jets of water as required Administration. This pump and its location must meet the following requirements:

2.1 pump capacity must be at least 40% of the total fire pump capacity required by this regulation, and in any case at least 25 m ^ 3 / h;

2.2 in the event that the pump delivers the amount of water required by paragraph 3.3.2.1, the pressure in any tap must be at least the minimum specified in paragraph 4.2;

2.3 Any diesel driven power source supplying the pump should be capable of being easily manually started from a cold state down to 0 ° C. If this is not impracticable, or if lower temperatures are anticipated, consideration should be given to the installation and operation of rapid start-up heating facilities acceptable to the Administration. If manual starting is impracticable, the Administration may authorize the use of other means of starting. These means must be such that the diesel powered power source can be started at least 6 times within 30 minutes and at least twice during the first 10 minutes;

2.4 any service fuel tank shall contain sufficient fuel to ensure that the pump operates at full load for at least 3 hours; Outside the premises with the main machinery, there must be sufficient fuel reserves to ensure that the pump operates at full load for an additional 15 hours.

2.5 under conditions of roll, trim, rolling and pitching that may occur during operation, the total suction lift and the net positive suction lift of the pump shall be such that the requirements of paragraphs 3.3.2, 3.3.2.1, 3.3.2.2 and 4.2 of this paragraph are met. regulations;

2.6 the structures limiting the space in which the fire pump is located should be insulated in accordance with a structural fire protection standard equivalent to that required by regulation II-2/44 for the control room;

2.7 It is not allowed to have access directly from the machinery space to the space in which the emergency fire pump and its power source are located. In cases where this is impracticable, the Administration may allow an arrangement such that access is through a vestibule, both doors of which are self-closing, or through a watertight door, which can be controlled from the area where the emergency fire pump is located, and which is probably not will be cut off in case of fire in these areas. In such cases, a second means of access must be provided to the room containing the emergency fire pump and its power source;

2.8 ventilation of the room in which there is an independent source of energy for the emergency fire pump should

to prevent, as far as practicable, the possibility of smoke entering or sucking the space in the event of a fire in the machinery space;

2.9 ships constructed on or after 1 October 1994, in lieu of the provisions of paragraph 3.3.2.6, shall meet the following requirements:

the room in which the fire pump is located must not be adjacent to the boundaries of machinery spaces of category A or to those spaces in which the main fire pumps are located. Where the above is impracticable, the common bulkhead between the two spaces should be insulated in accordance with a structural fire protection standard equivalent to that required for control stations under regulation 44.

3 in passenger ships of less than 1,000 gross tonnage and in cargo ships of less than 2,000 gross tonnage, if a fire in any of the compartments could render all pumps inoperative, other fire-fighting water supplies are available to the satisfaction of the Administration;

3.1 for ships constructed on or after 1 October 1994, the alternative means provided for in paragraph 3.3.3 should be an independently powered emergency fire pump. The power source of the pump and the kingston pump must be located outside the machinery space.

4 in addition, in cargo ships on which other pumps, such as general purpose pumps, bilge pumps, ballast pumps, etc., are located in the machinery space, arrangements have been made to ensure that at least one of these pumps having capacity and pressure required by paragraphs 2.2 and 4.2, could supply water to the fire main.

3.4 Measures to ensure that the water supply is always available should:

1 for passenger ships of 1,000 gross tonnage and above, be such that at least one effective jet of water can be supplied immediately from any fire hydrant in the interior spaces and that a continuous supply of water is ensured by automatically starting the required fire pump;

2 for passenger ships of less than 1,000 gross register tons and for cargo ships, to the satisfaction of the Administration;

3 for cargo ships, when periodically unattended maintenance takes place in their machinery spaces or when only one person is required to maintain the watch, provide an immediate supply of water from the fire main at an appropriate pressure, or by remote starting one of the main fire pumps from the navigating bridge, and

with control station for fire extinguishing systems, if any, or by continuously maintaining the pressure in the fire line by one of the main fire pumps, unless the Administration may waive this requirement on cargo ships of less than 1600 gross tonnage if the location of the access is

the machine room makes this redundant;

4 for passenger ships, if their machinery spaces are periodically unattended in accordance with regulation II-1/54, the Administration should determine the requirements for a fixed water fire-extinguishing system for such spaces, equivalent to those for a system for machinery spaces with a regular watch.

3.5 If fire pumps can generate pressures in excess of the pressure for which pipelines, taps and hoses are designed, all such pumps should be safety valves... The placement and adjustment of such valves should help prevent overpressure in any part of the fire line.

3.6 On tankers, in order to preserve the integrity of the fire line in the event of a fire or explosion, cut-off valves should be installed on it in the bow of the poop in a protected place and on the deck of cargo tanks at intervals of not more than 40 m.

4 Diameter of the fire line and pressure in it

4.1 The diameter of the fire main and its branches must be sufficient for efficient distribution of water with the maximum required supply of two simultaneously operating fire pumps; however, on cargo ships, it is sufficient that this diameter only provides a feed of 140m ^ 3 / h.

4.2 If two pumps simultaneously supply through the shafts specified in clause 8 the amount of water specified in clause 4.1 through any adjacent taps, then the following must be maintained in all taps. minimum pressure:

passenger ships:
gross tonnage
	reg.t and more
gross tonnage
	reg.t and more,
but less than 4000 reg.t
gross tonnage		in accordance with the requirements of the Administration
less than 1000 reg.t
cargo ships:
gross tonnage
	reg.t and more
gross tonnage
	reg.t and more,

4.2.1 Passenger ships constructed on 1 October. 1994 or after that date, instead of the provisions of clause 4.2, the following requirements must be met:

if two pumps simultaneously supply water through the shafts and taps specified in clause 8 to ensure the supply of the amount of water specified in clause 4.1, then a minimum pressure of 0.4 N / mm ^ 2 must be maintained in all valves for ships with a gross tonnage of 4000 reg.t and more and 0.3N / mm ^ 2 for ships with a gross tonnage of less than 4000 reg.t.

4.3 The maximum pressure at any valve shall not exceed the pressure at which the fire hose can be effectively controlled.

5 Number and location of cranes

5.1 The number and placement of taps should be such that at least two jets of water from different taps, one of which is fed through a one-piece hose, reach any part of the ship usually accessible to passengers or crew during sailing, as well as to any part of any empty cargo space, any cargo space with a horizontal method of loading and unloading, or any space of a special category, and in the latter case, two jets supplied through solid sleeves must reach any part of it. In addition, such cranes should be located at the entrances to the protected premises.

5.2 On passenger ships, the number and placement of cranes in accommodation, service and machinery spaces must be such that drop-out of the requirements of paragraph 5.1, when all watertight doors and all doors in the bulkheads of the main vertical zones are closed.

5.3 If, on a passenger ship, the machinery space of category A is provided for access at the lower level from the adjoining propeller shaft tunnel, two cranes shall be provided outside the machinery space, but close to the entrance to it. If such access is provided from other rooms, then in one of these rooms two cranes should be provided at the entrance to the machinery room of category "A". This requirement may not apply if the tunnel or adjacent spaces are not part of the escape route.

6 Piping and valves

6.1 For the manufacture of fire lines and valves, materials that easily lose their properties when heated should not be used if they are not properly protected. Pipes and valves should be located so that fire hoses can be easily connected to them. The location of pipelines and valves must exclude the possibility of freezing. On ships capable of carrying deck cargo, the placement of cranes should be such as to ensure easy access at all times, and piping should be routed as far as practicable to avoid the risk of damage from the cargo. If the vessel does not provide a hose and stem for every crane, full interchangeability of the connecting heads and stems must be ensured.

6.2 A valve should be provided for servicing each fire hose so that any fire hose can be disconnected while the fire pumps are running.

6.3 Isolation valves for shutting off the section of the fire line located in the engine room in which the main fire pump or pumps are located from the rest of the fire line should be installed in an easily accessible and convenient place outside the machinery space. The location of the fire main should be such that, with the isolation valves closed, all ship's cranes, except those located in the above-mentioned machinery space, can be supplied with water from a fire pump located outside the machinery space through pipelines running outside it. As an exception, the Administration may allow short sections of the emergency fire pump suction and discharge piping to pass through the machinery space if it is impracticable to bypass the machinery space, provided that the integrity of the fire main is ensured by enclosing the piping in a strong steel casing.

7 Fire hoses

7.1 Fire hoses should be made of approved abrasion resistant material by the Administration, and should be long enough to supply a jet of water to any area in which they may be required. Fire hoses made of wear-resistant material should be provided on ships built on or after February 1, 1992, and on ships built before February 1, 1992 when replacing existing fire hoses. The maximum length of the sleeves should be to the satisfaction of the Administration. Each hose must be equipped with a barrel and the necessary connection heads. Hoses, referred to in this chapter as "fire hoses", together with all the necessary accessories and tools, must be in a conspicuous place near taps or connections, ready for use at all times. In addition, in the interiors of passenger ships carrying more than 36 passengers, fire hoses must be permanently connected to the cranes.

7.2 Ships should be fitted with fire hoses, the number and diameter of which should be to the satisfaction of the Administration.

7.3 On passenger ships, at least one fire hose must be provided for each crane required in paragraph 5, and these hoses must only be used for fire extinguishing purposes or for checking fire safety.