Connection of metal pipes with compression fittings. How to connect a metal-plastic pipe with a metal

Installation of the pipe (Fig. 10) is carried out using special compression-type brass fittings. These fittings consist of a union, split ring and union nut and provide reliable connection pipes and fittings using a conventional wrench. When tightening the union nut, the press sleeve (O-shaped cut ring) is compressed on the pipe and provides a tightness between the fitting and the inner wall of the pipe.

Rice. 10. Connection of a multilayer pipe with a compression fitting

The main advantage of this connection is that the installation does not require any special equipment, and also, if necessary, it is possible to dismantle any connection. Once assembled, a node can theoretically be disassembled and reassembled, but, as practice shows, it is better not to touch the connection. Therefore, in the case of pipeline repair, you need to cut out the damaged part and insert a new one, connecting it with fittings. When connecting a pipe to a used fitting, the gaskets on it must be replaced with new ones (fig. 11).

Rice. 11. Gaskets on the nipple of the fitting

The pipe is cut perpendicular to the axis with a special pipe cutter for composite pipes, in extreme cases, a hacksaw with a fine tooth. The pipe is bent by hand or with the help of a special spring - a pipe bender. Two types of springs are used: some are inserted inside the pipe (practically not used), others are put on the pipe from above. The minimum bending radius of a pipe without a spring is 5 outer diameters of a bent pipe, with a spring - 3.5 diameters.

On the Russian construction market, there are almost all types of compression fittings produced in the world. In principle, their designs differ little from each other, but there is still a difference: manufacturers produce detachable and one-piece fittings (Fig. 12), but this is not the main thing. When purchasing pipes and fittings for them made in different places, you should make sure that they are compatible, since different manufacturers have the outer diameters and wall thickness of pipes, even for the same nominal pressure, may not coincide. In other words, it is better to buy fittings and pipes, if possible, from the same manufacturer.

Rice. 12. Diagrams of compression fitting connections of various manufacturers

When fixing metal-plastic pipes, a minimum of clamps and clamps are required, since the pipes perfectly retain their shape. The installation of the pipeline is carried out both according to the collector and tee installation scheme. When installing tee circuits (in the language of plumbers, this circuit is called a "comb"), fittings can be sequentially connected to the pipe or first mount the pipeline and then cut the fittings into it (Fig. 13).

Mark the installation location of the fitting

Put on the pipe a heat-insulating corrugation (optional item)

Rice. 13. Example of connecting a compression fitting

The sequence of connecting metal-plastic pipes with compression fittings:

1. Align the pipe with a minimum 10 cm straight line before and after the cut.
2. Cut the pipe at a right angle according to the markings.
3. Work the end of the pipe with a reamer, first with the calibrated side with chamfering no more than 1 mm, then with the other side at least to the notch, ensuring the correct rounded shape of the pipe.
4. Slide the flare nut and split ring onto the pipe.
5. Moisten the fitting.
6. Place the pipe on the fitting so that the end of the pipe rests flat against the edge of the fitting. Tighten the union nut by hand until it stops on the fitting. The nut should be easy to tighten, if this does not happen, then you are not twisting it along the thread. Further tightening of the nut forcibly will lead to damage to the thread and, as a result, to leakage of the connection and subsequent replacement of the fitting.
7. Holding the fitting body with one wrench, use the other wrench to tighten the union nut 1–2.5 turns so that 1–2 threads are visible. The use of wrenches with additional levers is not allowed - do not use excessive force or overtighten the nut.

To avoid fogging of pipes or to insulate them, special corrugated hoses are put on the pipes, most often made of foamed polyethylene. If for some reason the corrugation was not installed, and the need for it appeared, then it can be mounted later. For this corrugated pipe cut lengthwise and put on the pipe, after which they strengthen it with tape.

Figure 13 shows the installation of a tee fitting, in fact, the range of compression fittings is quite rich, it allows you to assemble a pipeline of almost any complexity.

Nipple with female thread (transition to pipe fittings) 16 × 1/2; 20 × 1/2; 20 × 3/4; 26 × 1; 32 × 1

Nipple with external thread(transition to pipe fittings) 16 × 1/2; 20 × 1/2; 20 × 3/4; 26 × 1; 32 × 1

Coupling (connection of two metal-plastic pipes) 16; twenty; 26; 32

Elbow with internal thread (transition to pipe fittings) 16 × 1/2; 20 × 1/2; 20 × 3/4; 26 × 1; 32 × 1

Elbow with external thread (transition to pipe fittings) 16 × 1/2; 20 × 1/2; 20 × (3/4; 26 × 1; 32 × 1

Elbow (connection of two metal-plastic pipes) 16; twenty; 26; 32

Tee with female thread (transition to pipe fittings) 16 × 1/2; 20 × 1/2; 20 × 3/4; 26 × 1; 32 × 1

Tee with external thread (transition to pipe fittings) 16 × 1/2; 20 × 1/2; 20 × 3/4; 26 × 1; 32 × 1

Tee with the same fittings 16; twenty; 26; 32

Reducing tee from 16-20-16 to 26-32-26

Crosspiece 16; twenty; 26; 32

Elbow (water socket) for fixing the mixer and other devices 16 × 1/2; 20 × 1/2

Double angle bracket for fixing the mixer and other devices
16 × 1/2; 20 × 1/2

Sweep 16; 18; twenty; 26

Caliber 16; 18; twenty; 26

Spring for bending metal-plastic pipes 16; twenty; 26; 32

Fittings are marked according to two indicators: by the outer diameter of the attached metal-plastic pipe and by the size of the thread with which the fitting is attached to the metal pipe, a squeeze, ball valve or other pipe fittings. For example, in the explanations to Figure 14 for a nipple with an internal thread, there are numbers 16 × 1/2, indicating that a reinforced-plastic pipe with an outer diameter of 16 mm is attached to this fitting on one side, and pipe fittings with a 1/2 thread on the other side inch.

When connecting and repairing metal pipes, as a rule, a threaded joint or welding is used. But in some cases, it is not possible to cut a new thread, and welding work is extremely difficult to perform due to the increased fire hazard or the inaccessibility of the junction of different sections of the highway.

In addition, these works require significant financial and time costs, and in this case, they use methods of connecting pipes without welding and threading, which allow to ensure a reliable and durable result without large investments and in the shortest possible time. We will briefly discuss these methods.

Metal pipes have a certain service life, and they are especially susceptible to corrosion in the area of ​​threaded connections when high temperature liquids. Sometimes, due to the poor quality of the material, fistulas appear in the body of the pipes, which require urgent repair, and in cast-iron sewer pipes ah, cracks and chips from mechanical stress can occur.

Force majeure requires a quick response to ensure reliable repair of gas, water, heating and sewer pipes without threads and welding. The industry has experience of such a connection of gas and oil pipelines, which provides not only a tight connection, but also the absence of corrosion on the butt parts.

The need for prompt and high-quality repairs, as well as the implementation of a tie-in with a branch from the mains, pushed the engineers to a number of design solutions. The basic principle of each of them is the connection of pipes without welding, which ensures a tight and strong connection of the joints, even with high pressure and hot media in the system.

This process is carried out using the following most popular devices:

• repair work with a clamp, in this way you can eliminate the malfunction of the water supply, sewer system and even repair the car pipe;
• flange connection bolted with rubber gaskets;
• repair and assembly clips for water supply systems;
• Gebo coupling or compression fitting, allowing to connect sections and make bends from the main pipe, where the temperature of the carrier is not higher than 80 ° C with the possibility of reuse;
• installation of pipes, rotary elements and branches using press fittings, which crimp pipes using press tongs and provide high strength and tightness of the permanent connection.
• trunk connections based on sealed heat-shrinkable couplings using special equipment.

When choosing, it is important to pay attention to the intended use of the product, since it can serve either as a temporary repair device, or be of a permanent operational nature, and its cost depends on this.

Unlike welded pipes, joints based on seals do not require special cutting of the ends, but only need to be cleaned from dirt, irregularities, rust and metal burrs in order to ensure the tightness of the joint.

Joining pipes with clamps, flanges and clips

The simplest devices for quick repair and joining of pipes are usually bolted and consist of two parts, which are put on the pipe and fixed in the right place with a rubber seal. An exception is the flanged connection of gas pipes, which is bolted through a rubber gasket in order to replace a section of the line.

Replacement of metal and plastic sewage drains during repairs is also based on replacing damaged areas with the installation of rubber seals without tightening, because there is no pressure in them. The main thing here is to prevent leaks, water flowing down by gravity and the appearance of odors.

Rapid tapping or repair using clamps and clips is not completely reliable, especially in systems with high media pressures and temperatures, and is a temporary measure. Clamps various designs are one-piece or split pipe-like structures and are tightened through gaskets at break-through points using bolts.

They are designed for the diameter of all pipes used up to 1520 mm and can be single, double or triple. They are characterized by quick installation in a damaged area, but they require accurate and consistent tightening of the bolts without distortions and deformation of the seals.

The connection with the help of repair clips is more reliable because they are a cast body made of painted metal, consisting of two detachable parts. This method also uses a thick-walled rubber gasket, and both parts are bolted together.

Installation of clamps and clips is carried out in the following sequence:

• the emergency area must be thoroughly cleaned of metal shavings, irregularities, rust and other contaminants;
• if a clamp is applied to the place of damage, a rubber pad is wound and sealed;
• if a repair clip is mounted, then a rubber seal is put on, the cut of which is lubricated with a silicone sealing compound;
• then the bolts are tightened sequentially and without distortions, in the case of the cage, crosswise.

Repair clips allow making a cruciform or T-shaped tie-in, and are also used when connecting two sections of the pipeline.

It is important during installation not to misalign the seal, not to overtighten the bolts and, after supplying fluid under pressure, re-verify the effectiveness of the repair and the tightness of the connection.

Connection of metal pipes using press fittings and couplings

The system of press fittings allows for strong, tight and durable connections of pipelines for various purposes, up to heating ones, and is designed for high pressure and temperature of the carrier. Also in the assortment there are tees and swivel elbows with an angle of 45 ° and 90 °, and if there is equipment for freezing, it is possible to quickly and efficiently connect new radiators directly during the heating season. A significant drawback of this system is the high cost of equipment because this method requires the use of a special tool for crimping the fitting or pressing tongs.

More simple solution the problem of joining steel, cast iron and plastic pipes is the use of split couplings UR-01 with double-sided bolted seal. These products serve for connections of pipes with a diameter of 50 to 300 mm and hold pressure up to 16 atm. The couplings are equipped with polyoxymethylene expansion rings with bikromet locks, and the body and pressure caps are made of high-strength painted cast iron. The O-rings are made of EPDM, and the entire structure allows for slight angular deflection, holds water hammer and protects against tensile loads.

An inexpensive split solution also includes the Gebo compression sleeve, which is available in one-sided and double-sided versions and allows tapping and corner connections. It consists of the following main details:

• main one- or two-sided durable body;
• sealing conical rubber ring;
• metal clamping ring;
• split clamping ring with a notch for fixing on the pipe surface;
• a threaded nut that provides a clamping, hermetic seal and fixation of the entire structure.

When assembling, it is very important to follow the assembly sequence of the Gebo coupling and correct installation tapered parts according to the manufacturer's instructions.

In double-sided design, the coupling has compression rings on both sides and serves for threadless connection of two parts. The assembly process is extremely simple, but requires effective cleaning of the installation site from rust, contamination and metal chips. Reliable fixation in terms of strength and durability is not worse than threaded connections and is provided both by friction of the sealing gasket and fixation on the pipe body using a compression ring. One of the advantages of this design is the ability to reuse this element with the replacement of the rubber ring with a new product.

What do we end up with?

The methods we have considered for connecting pipes without welding and threading are a quick opportunity to eliminate a breakthrough in the hot and cold water supply and sewerage system. The correct formulation of the problem and the competent choice of the product will provide you with the elimination of the problem and significant cost savings in an unforeseen situation that may occur in every home.

Compression fittings are very popular because they can be used to connect pipes made of a wide variety of materials: polyethylene, metal-plastic, copper, steel, polypropylene.

Benefits of using compression fittings when assembling a pipeline:

• no soldering is required when connecting polyethylene pipes;
• allow, if necessary, to disassemble the pipeline. For example, when conducting renovation works to replace a section of a pipe or to clean a pipeline if it becomes dirty;
• ensure the tightness of the system;
• this type of connection is resistant to vibrations and accidental mechanical stress on the pipeline;
• can be used in places of high humidity;
• are quite suitable for the installation of a pipeline intended for transporting drinking water;
• a wide range of different configurations (couplings, bends, tees, adapters) and diameters (from 16 mm to 110 mm).

Features of the use of compression fittings

1. Compression brass fittings for HDPE pipes are usually used for external piping installation. The use of compression fittings prevents slippage of the pipeline ends under tensile forces, under the influence of pressure and temperatures of the transported substances.
2. Compression fittings for multilayer pipes are made of nickel-plated brass. It is recommended to check the tightness of the connection by the compression fitting of metal-plastic pipes several times a year and their additional tightening is possible.
3. Compression fittings for copper pipes are used when it is not possible to use an open flame. Such fittings are made of metal-plastic, steel, copper and brass.

Compression brass fittings for copper pipes are in greater demand than copper or steel, since brass products are much cheaper and more malleable to work with. To increase the strength characteristics, brass products are additionally coated with nickel.

4. Compression fittings for polypropylene pipes are made of polypropylene. If it is necessary to connect polypropylene pipes with pipes made of another material, fittings with a plastic body and an internal metal thread are used.
5. Compression fittings for steel pipes are an alternative to welding pipes. But since compression fittings are significantly inferior to welding in terms of the strength of the connection, designed for a long-term result (when using compression fittings when assembling heating systems, under the constant influence of a high operating temperature of the transported liquid, the O-ring of the fitting may lose its initial performance properties, and the connection is depressurized) then it is recommended to use compression fittings as a temporary measure.
6. Compression fittings for connection are used in the assembly of external high pressure pipelines.
7. A compression fitting for connecting a metal pipe is used when carrying out repair work on a pipeline. The compression fitting will act as an adapter. It makes no sense to connect metal pipes with compression fittings - it is better to use welding.

Installation of compression fittings

Compression fittings consist of a body, split ring and union nut. The use of compression fittings for connecting pipes does not require the use of any special equipment. All you need is a pipe cutter and a wrench. When tightening the nut with a wrench, the split ring on the pipe is compressed, which leads to a strong and tight connection between the pipe and fitting walls.

The connection of polyethylene pipes with compression fittings is carried out in the same way as the connection of metal-plastic pipes. But for polyethylene pipes, due to the softness of the material used for the manufacture of pipes, the use of compression fittings with a split ring is not acceptable, since when the wall is compressed polyethylene pipe may well deform. In this case, the compression fitting consists of a body, a union nut and a rubber seal instead of a split ring.

Compression Fittings Cost

The price of compression brass fittings, depending on the diameter of the product and the manufacturer, ranges from 46 rubles. up to 470 rubles. (domestic manufacturer); from 250 rubles / piece up to RUB 2700 / piece (foreign manufacturer);

The price for compression plastic fittings, depending on the diameter of the product, as well as on whether the product is monopolypropylene or combined, with metal inserts, ranges from 20 rubles / piece. up to 1600 rubles / piece

Video

Look at the video for instructions on connecting HDPE pipes with brass fittings:

When conducting installation works when assembling the pipeline, it is recommended to use fittings of high quality, and made of a material similar to the material from which the pipes are made, and also taking into account the functional purpose of the installed pipeline.

Today, the market for plumbing materials is incredibly abundant. Despite the emergence of a mass of modern and appropriate materials, most owners still use metal pipes. The connection of these pipes is carried out using special devices - fittings. This article will discuss which fittings to choose for metal pipes.

Fittings classification is as follows:

• Threaded;
• Crimp;
• Flanged;
• Welded (with smooth edges suitable for welding).

They differ in purpose, installation technology, dimensions and shapes, so it's impossible to say for sure which fittings are better. To understand how to select steel pipe fittings for a particular situation, you need to consider each type in detail.

Threaded fittings for metal pipes

For the manufacture of threaded fittings required for the installation of steel pipes for the main water supply, high-strength metal is used. A cylindrical thread is initially cut on the workpieces. To achieve tightness, the thread is sealed with a linen gasket treated with a linseed oil impregnation. Also, FUM tape or other materials can be used as a sealant, which can now be purchased at any plumbing store.

The material for the manufacture of connecting fittings can be steel or cast iron. In accordance with the requirements, ready-made threaded fittings for metal pipes do not have inclusions of other substances or visually noticeable cavities that arise due to incorrect production technology metal products... This requirement is relevant for both external and internal surfaces of fittings. The standards also indicate that the ends of the valves should be located at a 90-degree angle relative to the axes of each passage. Such a metal pipe connector will be very reliable and will last for many years.

Sometimes, during production, the edges of the fittings are supplied with plump sides, which do not carry a functional load, but serve only as a decorative element. Steel shut-off valves are devoid of such an addition.

The nominal diameter of threaded fittings can vary from 8 to 100 mm. As a rule, this type of fittings is installed on water mains in which the operating temperature does not exceed 175 degrees, and the upper pressure limit is 1.6 MPa.

The main advantage of the threaded connection, which favorably distinguishes such fittings from other types, is the possibility of their disassembly: if necessary, you can easily dismantle the pipes without the cost of cutting equipment or hiring specialists (in more detail: ""). Most often, threaded fittings for steel pipes are installed in apartments, private houses and on summer cottages, since it is in these cases that these adaptations fully justify their purpose.

Compression pipe fittings

Compression fittings for steel pipes have a lot of positive qualities therefore they are used quite often. They are well suited for the installation of various communications in different conditions and do not lose their effectiveness depending on them. Compression fittings are installed mainly on indirect connections - and these are various angles, turns of the pipeline, the connection of pipes of different diameters, branches and even a direct connection of metals.

Due to this category of fittings, the disassembly of individual parts of the line is greatly simplified. Also, these devices are successfully used to achieve tightness and smooth installation of pipe joints and pipe sections. Compression fittings prevent liquid from leaking from the pipeline and getting various debris into it from the outside.

Steel crimp fittings should not be used in all situations - but knowing their specifics, you can significantly increase the reliability of the pipeline and ensure its normal functioning. The operating conditions of the considered type of fittings coincide with the previous one - the temperature of the liquid in the pipeline should not exceed 175 degrees, and the working pressure cannot exceed 1.6 MPa. Pipes connected by compression fittings can transport gaseous substances, various solvents, water, oils and others.

Types of crimping fittings

For metal pipes, one or two ring press fittings can be used. Press fittings are quite convenient, but they are firmly pressed against the pipes, so it will not be possible to disassemble them in the future, and the pipes will have to be cut out if necessary, replacement or repair. For this reason, compression fittings for metal pipes are used only in hard-to-reach places or for other specific reasons.

Compression fittings are designed with one or two ferrules that secure the device to the pipe without using a threaded or welded joint. The materials and characteristics of the ferrules may be different, but the requirements for them are the same - the ability to withstand a certain pressure and keep the pipes connected for a long time.

Compression metal fittings for steel pipes have many advantages in their arsenal:

• Complete sealing of the pipeline without the use of welding or other methods of connecting pipes;
• Possibility of multiple mounting and dismounting;
• Reliable fixation of pipes throughout the entire period of operation;
• Ability to withstand vibration impact for a long time;
• Compression fittings are used successfully in high pressure equipment.

Fittings types

Fittings may differ not only in design, but also in their purpose, depending on which the following types of devices can be distinguished:

1. Corner fittings... Such elements are used in the event that it is necessary to turn the pipeline at a certain angle. The use of corner fittings greatly simplified the installation of pipes, because earlier for these purposes it was necessary to use welding, which took much more time.
2. Straight couplings... These parts are used to connect two straight pipes. Straight couplings are simple in design and limited in scope - in practice, such elements are only suitable if you need to change a pipe section or establish a connection between two parts of the pipeline. Very often these couplings are a connecting element of a pipe and, for example, measuring equipment. Also, couplings are needed for mounting products with different diameters or differing materials.
3. Tee fittings... The purpose of such fittings is encrypted in their name - tees have three branches for connecting three pipes. The standard metal pipe tee has a right angle or 45-degree angle to allow the most convenient way to run the pipes. Tee fittings can be used to connect pipes of the same or different diameters.
4. Cross fittings... These fittings are a logical continuation of the tees theme - the cross has four inlets and allows you to connect four metal pipes. All the outlets of the cross are located at an angle of 90 degrees relative to each other.

The use of different fittings makes it possible to significantly simplify the installation of the pipeline without using welding or other special equipment for these purposes.

Conclusion

The choice of suitable fittings for specific conditions must be extremely competent and deliberate. It will not be superfluous to consult a specialist or seller. Own experience you also need to connect and disassemble yourself - for example, high-quality fittings for metal pipes always have smooth surface without defects, scratches and sagging. Right choice connecting devices will allow you to create a reliable pipeline that does not have flaws in the form of leaks.

The majority of specialists and professionals in the field of repair and construction work recently more and more often recommend the use of metal plastic pipes, 3when the plumbing pipeline is being repaired and replaced.

Such pipes are quite practical and have a minimum number of disadvantages. The price is quite affordable, in operation they have a long service life (50 years), in transportation and installation they are easy and unpretentious.

And, nevertheless, you should know a few points on how to properly connect metal-plastic pipes in various variations.

Correct connection of metal-plastic pipes is not complete without the help of appropriate tools. And any competent repairman, a plumbing specialist or an ordinary owner of a house or apartment knows about this.

If you suddenly needed to independently install plastic pipes at home, connecting them different ways and elements, then you will need the following tools and equipment:

• spanner keys (usually they are used in two);
• sliding key;
• pipe bender (as a rule, the simplest pipe bender is used);

Pipe cutter

As cutting pipes into all kinds of pieces, separating pieces of pipe from the coil or other methods of cutting metal-plastic pipes, you can use a special tool - a pipe cutter, which is capable of mechanically manually cutting pipes with a maximum diameter of 42 mm.

It consists of handles-holders, internal blades made of durable tool steel and a locking clip, which holds the two handles in the closed non-working position.

In the absence of this tool, you can use an ordinary hacksaw for metal or a strong sharp knife as a pipe cutter.

Any tool capable of cutting metal-reinforced plastic will work, but only a pipe cutter can provide a clean and accurate perpendicular cut. Indeed, for a tight connection of pipes, an ideal perpendicular cut is required.

Spare and adjustable wrenches

These wrenches are necessary in order to dismantle and assemble the reinforced plastic pipeline and secure them with nuts, fittings and other threaded connections.

Photo: box wrench adjustable wrench

Open-end wrench

It is used only when necessary, but most often when connecting metal-plastic pipes with metal pipes.

Photo: open-end wrench

Caliber

With the help of this tool, the alignment of the cut planes and the chamfering from the inside of the pipe are carried out. It is thanks to the gauge that the complete tightness of the connection of the pipe sections and the ends of the fitting is ensured.

Photo: caliber

Crimp pliers

These tools are needed, for the most part, where couplings are used that need to be pressed down with pliers.

Photo: press tongs

Pipe bender

In those places where smooth bends of metal-plastic pipes are required or it is not possible to cut them off, you can bend them using a pipe bender. Thus, the pipes will remain solid, there will be no need to cut them, which will increase the service life of the pipes.

Photo: pipe bender

Expander

With the help of an expander, the necessary expansions of the holes inside the pipes are made for permanent connections.

Photo: expander

Connection methods

There are several ways to connect metal-plastic pipes, which are the best options to ensure complete sealing at the joints of the pipeline, which means efficient and trouble-free water supply.

But in order to use this or that method of connecting pipes, you first need to properly prepare the place for their installation and take into account all the important rules for installing metal-plastic pipes.

Preparatory work consists in planning the place where the pipeline will be installed. To do this, calculate all the dimensions and draw all the lines on the walls or floor, where exactly the sections of pipes, their corners, adapters, fittings and other components will be located.

Important! The beginning of each pipe line should be laid from the water point to the tap, flush cistern or a radiator. The number of corners, tees or crosses should be as small as possible, otherwise their many will slow down the flow of water, and, accordingly, the pressure.

All connecting sections of the pipeline must be located in accessible places because they require more frequent revisions and repairs. After the preparation is completed, the assembly of the entire pipeline begins.

Press fitting connection

In places of turns, corners and various transitions, devices such as fittings for connecting metal-plastic pipes are used, which firmly secure the connected sections of the pipeline.

This device is especially convenient when you need to connect the ends of pipes of different diameters. Therefore, fittings that connect pipes with the same diameter are called straight, and those that connect the ends are transitional.

Press fittings together with the entire piping system can be installed in concrete screed, which is much more convenient in the installation of underfloor heating, for example, in comparison with compression fittings. They come in the following configurations:

Female nipple	Male nipple (transition to pipe fittings) 16 × 1/2; 20 × 1/2; 20 × 3/4; 26 × 1; 32 × 1	Clutch 16; 20; 26; 32
Elbow with female thread (transition to pipe fittings) 16 × 1/2; 20 × 1/2; 20 × 3/4; 26 × 1; 32 × 1	Elbow with external thread (transition to pipe fittings) 16 × 1/2; 20 × 1/2; 20 × 3/4; 26 × 1; 32 × 1	Gon (connection of two metal-plastic pipes) 16; 20; 26; 32
Female tee (transition to pipe fittings) 16 × 1/2; 20 × 1/2; 20 × 3/4; 26 × 1; 32 × 1	Male tee (transition to pipe fittings) 16 × 1/2; 20 × 1/2; 20 × 3/4; 26 × 1; 32 × 1	16; 20; 26; 32 Reducing tee from 16-20-16 to 26-32-26
Crosspiece 16; 20; 26; 32	Elbow (water socket) 16 × 1/2; 20 × 1/2	Double elbow for fixing the mixer and other devices 16 × 1/2; 20 × 1/2

Various connections with press fittings help to connect the pipes to each other in such a way that later the connection is one-piece - this ensures complete sealing of the installation, and hence the efficiency of water supply.

Typically, these are press fittings with steel or brass ferrules, and fittings with push and slide clamp.

Photo: various pressfitting connections

The connection of metal-plastic pipes with a crimp press fitting usually occurs in the following sequence:

• cut the pipe to the required size with a pipe cutter;

Photo: cut off the pipe

• we process the edges of the cut pipe with a caliber;

Photo: we process with caliber Photo: we put a crimp on the pipe

• insert the fitting using rubber O-rings (for electrocorrosion);

Photo: insert the fitting

• we crimp the coupling with electric or manual press tongs. When working with electric press jaws, do not put your fingers on the metal parts of the coupling or the tool itself. Work exclusively with rubber gloves and hold the device only by its special plastic handles;

Photo: crimping the coupling with electric or manual press tongs Photo: the clutch should take on the bright outlines of the rings

Connections of this kind are based on couplings that need to be firmly clamped, and therefore they are considered the most reliable and can be safely used in the communications of a hidden-type pipeline.

Important! The most important rule in working with press fittings is one-time crimping of the coupling, re-clamping it with press jaws will lead to cracks, thinning of the material, and then the failure of the entire pipeline system.

Compression fittings for reinforced plastic pipes

Compression fittings are simplest mechanism, which consists of a union, a split ring and a union nut. That is why such a pipe connection is considered unpretentious and economical because no additional special tools are required.

It is enough to use an ordinary wrench, and if necessary, at the points of connection with compression fittings, the pipeline can be easily dismantled and the necessary repairs of pipe parts, replacement of gaskets on the fitting and other work.

Connections using compression fittings are as follows:

Photo: connection with compression fittings of metal-plastic pipes

When choosing compression fittings, be sure to pay attention to their manufacturer. It is best to choose fittings from the same manufacturer as the metal-plastic pipes you purchased.

Because many manufacturers produce fittings of the wrong diameters and may not fit your pipes. In the process of installing the pipeline with the connection of compression fittings, no pressing jaws or any other tools are required.

It is enough to use a wrench and, if necessary, a pipe cutter.

With the pipeline already installed, the third pipe with the compression fitting is connected as follows:

• mark with a simple pencil on the existing pipeline the pipe cut point where the third pipe will be inserted;

Photo: mark the place where the pipes are cut Photo: cut the pipe at the marked places

• we put on the pipe a corrugated insulation (if necessary, but usually this is done so that the pipes do not fog up and condensation does not form on them);

Photo: we put on the pipe a corrugated insulation

• calibrate the ends of the pipe (mandatory item);

Photo: Calibrate Pipe Ends

• we put union nuts and O-rings on the ends of the pipe, and then insert the fittings;

Photo: we put union nuts on the ends of the pipe

• we fasten with wrenches the nuts holding the pipes with fittings.

For the convenience of working with compression fittings, the length of the pipe sections before and after the cut should be at least 10 cm.

Important! Pipes are necessarily cut at right angles and then calibrated by all sides of the gauge: first, 1 mm of the lead-in chamfer is removed, and then with the other side to the mark-risks.

Moisten the pipe slightly before placing it on the fitting. When tightening the nuts, do not overtighten them, as the threads can break off so quickly.

With slide-on fittings

Sliding fittings are installed as easily as previous types of connections. First, the pipe is cut in the right place. Then a sleeve is put on its end (or two sleeves are put on at both ends).

Therefore, the end of the pipe is processed with an expander in order to slightly expand the hole in the pipe. Further, the pipe is installed on the fitting, the coupling is clamped using press tongs and pressed onto the fitting.

Here, an important element and feature of the installation is the principle of pressing the sleeve or sleeve of the push-on fitting onto the end of the pipe extended by the expander, which is put on the fitting.

It is very important to press the pipe against the fitting as tightly as possible while you will slide the press-on sleeve onto the end of the pipe. This is what will ensure the tightness of the connection.

Such methods make it possible to make the connection of pipes without welding, glue or any questionable connections, as well as to further maintain the integrity of the entire pipeline.

Connection of metal-plastic pipes with metal

From time to time, practice shows that when replacing plumbing in some places, it is necessary to attach metal-plastic sections of the pipeline to metal pipes.

The accuracy and precision of all execution is very important here. step by step recommendations... The most common way is to use a compression fitting when connecting a metal-plastic pipe with a metal crimp fitting.

The work should be done in the following sequence:

• screw the fitting onto a metal (cleaned from rust, if the pipe is old) with an open-end wrench. In order to avoid any leaks in the future, use old way- tow and paint. It is necessary to soak the tow with paint and wind it on the pipe thread with a thin layer, and then screw the fitting onto its end;

Photo: we screw a fitting onto a metal pipe

• now start working with the metal-plastic pipe, while the paint on the metal dries up. Put the press washer together with the nut on the end of the plastic pipe and calibrate the pipe;

Photo: calibrate the pipe

• further, put the end of the metal-plastic pipe on the cone screwed to the metal pipe;

Photo: put the end of the metal-plastic pipe on the cone screwed to the metal pipe

• again use an open-end wrench and tighten the nut so that the washer is tightly compressed metal-plastic pipe.

Photo: tighten the nut

With polypropylene pipes

In those places where there are connections to boilers, washing machines, heating gas water heaters and other connections that do not require the installation of massive pipes are most often used polypropylene pipes(PPT).

Such pipes are also called plastic pipes because they are made of practically the same plastic. Possible options for connecting such pipes to metal-plastic ones also provide for such devices as fittings.

These connecting elements show themselves well both in connections with metal pipes and metal-plastic ones.

Female thread coupling (transition to pipe fittings)	Male thread coupling (transition to pipe fittings) 16 × 1/2; 20 × 1/2; 20 × 3/4; 25 × 1; 32 × 1	Clutch sixteen; twenty; 25; 32, etc.
Elbow with female thread (transition to pipe fittings) 16 × 1/2; 20 × 1/2; 20 × 3/4; 25 × 1; 32 × 1	Elbow with external thread (transition to pipe fittings) 16 × 1/2; 20 × 1/2; 20 × 3/4; 25 × 1; 32 × 1	Elbow 45, 90 ° (connection of two polypropylene pipes) sixteen; twenty; 25; 32, etc.
Female tee (transition to pipe fittings) 16 × 1/2; 20 × 1/2; 20 × 3/4; 25 × 1; 32 × 1	Male tee (transition to pipe fittings) 16 × 1/2; 20 × 1/2; 20 × 3/4; 25 × 1; 32 × 1	Equal tee sixteen; twenty; 25; 32, etc. Reducing tee transition to different diameters
Crosspiece sixteen; twenty; 25; 32, etc.	Elbow (water socket) for fixing the mixer and other devices 20 × 1/2; 25 × 1/2	Pipe bypass to bypass another pipe when mounted in one plane

With heatsink

The principle of attaching metal-plastic pipes to radiators mainly consists in the use of special adapters and, already familiar to us, fittings.

There are also several schemes for connecting piping and risers to radiators:

• the bottom-down scheme is used for hidden piping in the floor. In the presence of thermostats and valves, special adapters are necessarily used, which would firmly fix all the necessary connections;

Photo: bottom-down scheme

• lateral connection also requires the use of adapters, chrome-plated or brass tees with metric threads;

Photo: side connection

• connection with an exit from the floor. With such a connection scheme, a telescopic fitting effectively provides a "runaway" of the vertical front pipes;

Photo: connection from the floor

• corner connection, or "diagonal" scheme. Not only with this method, but also with others, swivel knees are also used if necessary.

Photo: corner connection

With tap

Just as we considered the connection of metal-plastic pipes with various other pipe materials and types of plumbing, in the same way they use the connections of metal-plastic pipes with taps.

Fittings are also used here, preliminary calibration of the pipe end and connection in this order:

• you need to unscrew the connecting fitting;
• remove plastic or metal clamping nuts and O-rings;
• put on the clamping nut and O-rings on the metal-plastic pipe;
• tightly insert the pipe into the fitting;
• tighten the O-ring and tighten with the clamping nut;
• the other end of the fitting connects to check valve, which is pre-installed to the inlet of the valve itself.

With flexible hose

Such connections are usually performed where water supply is required to washing machine, boilers and other devices and structures. The fittings here should be used with fittings that are specifically designed for flexible hoses.

Important! Also, a nut must be provided at the end of the water hose, which will fasten the entire connection to the fitting.

You need to pay attention to this when buying this or that hose for your future system.

How to disassemble

It must be said right away that not all types of connections can be disassembled without damage and replacement with new connecting elements.

It depends on what technology for joining metal-plastic pipes was used, which, for example, fittings were used to connect certain sections of the pipeline.

If press fittings or fittings with push-on couplings were used, which were then pressed using press tongs, then such connections are considered non-separable, and therefore their replacement, if necessary, will be done by completely dismantling and cutting off this section with pieces of pipes.

Then you need new accessories for connecting fittings, as well as an additional piece of pipe.

If connections were used using compression fittings, then it will not be difficult to unscrew the clamping nuts. And, therefore, it will be easy to disassemble the entire section where the pipes are connected.

If it flows

To eliminate the leak at the joints, you must first find and determine the cause and nature of the breakdown.

• check if the connecting nut is not loosely screwed on and slightly tighten it up to the stop, but not strongly, so that the thread does not burst or break;
• turn off the water supply, unscrew the fitting and check whether the pipe fits tightly into the fitting or whether the pipe fits tightly when it was pushed onto the fitting. If just such a problem was found, then the pipe must be pushed in until it stops, and then also tightened in the reverse order. But this only applies to collapsible connections;
• if you have a ferrule then check if the ferrule is tight and if not, then press it down again with the pliers. Only here, do not overdo it, so as not to damage the surface of the metal and prevent it from crumbling or cracking;
• if you calibrated the end of the pipe with a knife, then water will flow and seep through the rubber bands of the fitting, which cannot fit snugly and will slide out. This malfunction is easy to eliminate by disassembling the connection and calibrating the end of the pipe with a gauge to smoothness and reinstalling everything in the reverse order;
• if the sealing rings are worn out or unusable, then they should be replaced.

Having carefully studied and considered all possible options for connecting metal-plastic pipes using fittings and all kinds of tools, you can easily independently correct this or that undesirable situation with your water supply in the house or repair the pipeline yourself.

Thorough preparation for work will also help you to repair or install a metal-plastic pipeline on your own and at the highest level.

Video: Secrets