Flanged swing check valve for large diameters. Check valves

In a lift check valve, the shut-off element is a lift spool. Under the action of water pressure, the spool rises, allowing the flow to pass. If the pressure drops, the spool is lowered onto the seat, preventing flow back. Such valves are installed only in horizontal pipe sections. Required condition- vertical arrangement of the valve axis.

The valves are divided into four groups according to the method of attachment:

• Welded attachment: The non-return valve is welded to the pipeline. It is used when working in aggressive environments.
• Flange mounting: The check valve is connected to the pipeline through gasket flanges.
• Coupling fastening: the valve is fastened to the pipeline through a threaded coupling. Used in systems not large diameter.
• Wafer fastening: the check valve does not have its own fastener. Clamped between pipeline flanges. It is used in areas with limited dimensions.

Lift check valves with a safety net at the inlet and designed to be installed at the beginning of the suction line are called foot valves.

Advantages of lift check valves:

• simplicity of design;
• reliable tightness;
• the possibility of repair without dismantling the entire valve.

Disadvantages of lift check valves:

• high hydraulic resistance;
• the possibility of jamming the shutter in the guide part of the cover when using the valve in systems with a contaminated working environment;

Ball check valves

In a ball check valve, a ball element serves as a gate. A spring is used as the clamping element, pressing the ball against the seat. These valves are usually made for small pipe diameters and are used as domestic plumbing equipment. The ball check valve is inferior to the spring disc valve in dimensions.

Swing check valves, principle of operation:

In this design, the shut-off element is a slam-shut valve. The flapper pivot axis is located above the through hole. Under the action of the “slam” pressure, it leans back and does not interfere with the passage of water. When the pressure drops below the permissible value, the spool falls and closes the bore. In large diameter check valves, swipe the spool against the seat, which leads to a rapid failure of the structure. With further operation, this provokes the occurrence of a water hammer when the check valve is triggered. Therefore, rotary check valves are divided into two groups: Simple - valves with a diameter of up to 400 mm. They are used in systems where shock phenomena cannot seriously affect the operation of the hydraulic system and the valve itself. Bumpless - valves with devices that ensure a smooth and soft fit of the spool on the seat. The advantage of rotary valves is the ability to handle large systems and low sensitivity to environmental contamination.

The PASADOR company offers to buy check valves of various modifications at attractive prices. We supply products to all regions of Russia.

Pipeline fittings of this type are used to prevent reverse movement of the working medium (water hammer or back pressure). Our range includes threaded, flanged and wafer-type products designed for industrial and domestic use and designed for a long service life.

The advantages of check valves are:

• automatic actuation without additional power consumption;
• reliability;
• performance of functions both in normal and emergency operating conditions;
• lack of significant impact on throughput pipeline.
• opening the shutter at minimum pressure 0.5 bar (gravity).
  

You can buy check valves for household and process water supply systems, heating, steam systems, oil and chemical industries, sewage systems at reasonable prices. The products can be used in pipelines for the transportation of non-aggressive liquids and gases.

The catalog contains check valves with threaded, flanged and wafer-type fastening in cast iron, carbon and stainless steel, brass, bronze bodies. Most models are designed for horizontal and vertical installation.

The design consists of a body and a shutter, the mechanism of which is a spool. In the absence of flow, this type of valve is closed. Under the influence of the moving working medium, the shutter automatically opens and closes when it stops. The spool opens in only one direction, therefore no backflow of the medium is possible.

Types of check valves

We offer ball and globe check valves with different kinds fastening.

Conventional feed-through models are for horizontal mounting only. Ball check valves can be installed horizontally and vertically, since they use a ball element as a shutter. These types of fittings are available with threaded and flange fastenings.

Wafer check valves are installed in flanged bursts of pipes. They can be mounted vertically or horizontally. A flat disc is used as a shutter. Double-leaf valve designs are equipped with damping elements to successfully resist water hammer.

The main task that a flanged check valve, installed on pipelines for various purposes, solves, is to ensure the movement of the transported medium in one direction. Design features a check valve, for the installation of which a flange is used, allow such a device to automatically stop the movement of the transported medium at the moment when such a movement begins to be performed in the wrong direction. Flanged check valves are mainly installed on pipelines through which liquid media are pumped.

Features and applications of check valves

Check valves different types(including flanged ones) are used to protect the pipeline from:

• the occurrence of reverse flows of the working environment in it;
• hydraulic shocks.

Reverse flow in pipelines, as is clear from its name, is the movement of the working medium in the opposite direction. This can happen, in particular, when the pump, which provides the supply of the working medium and its movement, is turned off. If for heating systems such a phenomenon as a reverse flow is not particularly critical, then in sewer and plumbing systems, as well as in pipelines through which oil products and other media are transported, it cannot be allowed to occur. That is why the use of check valves in such pipeline systems is a must.

Another undesirable phenomenon, from the consequences of which pipeline systems can be protected by a flanged, wafer-type or any other valve, is water hammer. It is characterized by the fact that a sharp drop in the pressure of the transported medium occurs in the pipeline, which leads to the formation of a shock wave passing along the entire length of the pipeline system.

Water hammer can eventually lead to the destruction of individual sections of the pipeline and the failure of the elements that are used to ensure its normal operation. With the help of check valves, installed by means of flanges or in any other way, the system is divided into separate isolated sectors, which effectively protects it from the effects of a water hammer.

Operating principle

The principle by which check valves work is quite simple, meanwhile such devices are very effective and are able to provide reliable protection parts of pipeline systems. Any check valve, regardless of the type, is made up of a body (steel or cast iron) and a shut-off element located in it. The locking mechanism works due to the pressure of a special spring, the stiffness of which can be adjusted.

The spring, which the check valves are equipped with, ensures that their shut-off elements are opened only in one direction - in the direction of the correct movement of the transported medium. By exerting pressure on the shut-off element held by such a spring, the liquid or gas pumped through the pipeline opens it and begins to move in the required direction. As soon as the pressure of the working medium begins to drop in the direction of opening the valve, the shut-off element closes, preventing the liquid or gas from moving in the opposite direction.

Types and properties

The design of the check valves for the installation of which flanges are used may be different. The choice of a flanged valve with a certain type of shut-off element depends on what tasks such a device is intended for.

So, depending on the design of the shut-off element, they are distinguished:

• rotary valve;
• lift type check valve;
• check valve with ball locking element;
• two-leaf check valve;
• foot check valve equipped with a mesh.

The rotary check valve is a locking device, the main part of which is a steel slamming disc, fixed on a spring-loaded axle. At the moment when such a check valve is open, the disc in its inner part is parallel to the movement of the working medium, and when it is closed - perpendicularly. The flanged swing check valve has a simple structure and, accordingly, low cost. If we talk about the disadvantages of this type of check valves, the most significant of them is that their rotary mechanism at the moment of closing slams the locking disc too much, which eventually leads to wear of the seat. Rotary check valves equipped with a special mechanism that ensure smooth closing of the shut-off disc are devoid of such a drawback. However, these improved flanged rotary valves are more expensive, which somewhat limits their application.

In flange-type lift check valves, a special spool is used as a shut-off element, which, under the pressure of the working flow, rises along the vertical axis, and when the pressure decreases, it drops to its seat, blocking the movement of the medium transported through the pipeline. It should be borne in mind that such valves, due to the peculiarities of their design, can only be installed in a vertical position.

Ball check valves, as their name suggests, use a ball-shaped spool as a shut-off element. Big size does not allow their use as interflange locking devices.

The check valve, which is mainly produced in the wafer design, involves the use of two slamming leaves at the same time in its design. Each of them is connected to a spring, which regulates the force of their resistance to the pressure of the working stream. The wafer-type butterfly valve, due to the small size of its shut-off elements - the flaps - is very compact in size.

Check valves, the design of which is additionally equipped with a strainer, are used for installation on pipeline systems for pumping oil, gas or water from underground sources. Such devices, the most popular model of which is 16CH42R, simultaneously solve two important problems: their shut-off mechanism does not allow liquid or gas to return back to the source, and the mesh protects the pipeline from large debris entering it.

Model 16CH42R, the body of which is made of steel or cast iron, is characterized by wide versatility and can be installed on pipelines or pumps used for pumping both liquid and gaseous media.

Flanged and Wafer Check Valves: Differences

Flanged check valves can be one of the following types:

• flanged;
• interflanged.

On flange-type devices, the flange on the delivery part and the return flange are welded to the valve body and form a single whole with it. Flanged check valves are mainly used to equip pipes with large diameter, with the help of which the transport of working media is carried out on an industrial scale.

Wafer check valves have virtually no fasteners. This type of installation, as mentioned above, is very often used for the installation of two-leaf check valves. In this case, the valve itself (in particular, a two-piece wafer type) is installed between two flanges fixed at the ends of the pipes to be connected. After its placement in special seats, which are equipped with sealing elements, the flanges are pulled together using threaded rods. Despite the apparent unreliability of such a connection, if it is performed correctly, the reverse wafer valve locks in with the same reliability as any other type of device.

Check valves can be installed on piping systems using not only flanges, but also couplings or welded joints. However, if we talk about large-diameter pipelines, such valves are installed on them only using flanges.

Advantages and Disadvantages of Flanged Type Check Valves

Since flange-type check valves are most often used to equip pipelines through which the working medium is transported with high intensity, the internal elements of such devices (in particular, the shut-off mechanism) experience significant shock loads during operation. In addition, the flange-type check valve, due to its significant dimensions, itself is the cause of water hammer. In the process of closing the valve flaps in the pipeline in which it is installed, the pressure inevitably rises, which leads to the formation of a water hammer.

In those pipeline systems in which water hammer is not able to significantly affect the performance of both individual elements and the system as a whole, check valves are used simple type... The diameter of the latter, as a rule, does not exceed 400 mm. In other cases, shockless check valves are used. Smooth and soft closing of the shut-off element in bumpless flanged valves can be provided by special weights or hydraulic dampers. Meanwhile, when choosing bumpless check valves for equipping a pipeline system, it should be borne in mind that they can be installed only in horizontal sections.

The most significant advantages of flanged check valves include:

• compact dimensions, which makes it possible to install such devices in almost any section of the pipeline system;
• the ability to work effectively even in those systems in which the working environment is characterized by severe pollution;
• the possibility of installation on pipelines with a large diameter.

Features of choice

The main parameters that you should pay attention to when choosing a check valve (including a flanged one) are:

• working pressure at which such a device can operate;
• nominal bore diameter.

You can find out what operating pressure the check valve corresponds to by the device labeling, in which this parameter is denoted by the letters RU. The numbers in the marking after such letters indicate the operating pressure for which the device is intended. For example, the designation RU16 indicates that a flanged valve can operate at 16 bar without being exposed to excessive wear.

The nominal diameter, on which it depends on which pipeline a flange-type valve can be installed, is designated by the letters ДУ. Accordingly, the numbers following in the marking after these letters indicate the value of the nominal diameter of the check valve in millimeters. When choosing a check valve for this parameter, keep in mind that such a product can only be mounted on pipeline elements that have the same dimensions. In other words, the DU80 model, for example, can be installed only on pipes or other elements of the pipeline system, the landing diameter of which corresponds to a value of 80 mm.

When installing flanged check valves, strictly adhere to the following rules.

• Installation should be carried out by specialists who have previously been trained and received permission to perform work of such a plan.
• The part of the pipeline system where the installation is performed is completely disconnected from the supply of the working medium.
• Before starting the installation, you should make sure that the installed product in terms of its characteristics fully complies with those climatic conditions in which it will be operated.
• If a wafer-type check valve is installed, then first its flange part is mounted, and only then it is fixed in it.
• Before feeding the medium flow into the pipeline, make sure that the check valve is securely installed and all the required connections are made.

And in conclusion, a short video with a visual demonstration of the principle of operation of the rotary check valve.

The check valve rotary flanged Granlock RD30 was invented to protect pipelines from the backflow of the working medium. Designed for pipelines transporting technical hot and cold water, steam, neutral media.

Installation

The rotary check valve can be installed both horizontally and vertically. Installation to the pipeline is carried out using flanges. The direction of flow of the medium must match the direction indicated on the valve. The valve is installed on a horizontal pipeline so that the disc axis is higher than the pipeline axis and is located in the horizontal plane. On a vertical pipeline, the valves are installed with the inlet pipe downwards so that the disc axis is in the horizontal plane.

Specifications

Flange connection according to DIN 2501 (DIN 2633 on PN 1.6 MPa) / EN1092-2.

Mating flanges can be used Russian production according to GOST 12820-80, 12821-80 at PN 1.6 MPa.

Specification

Dimensions and parameters

vendor code	DN, (mm)	L, (mm)	D, (mm)	D1, (mm)	D2, (mm)	b – f	Z? O d	H, (mm)	Kv, (m3 / h)	Weight (kg)
2130411	50	200	165	125	99	20-2	4x19	115	82	13,0
2130412	65	240	185	145	118	20-2	4x19	130	130	17,40
2130413	80	260	200	160	132	22-2	8x19	147	220	24,40
2130414	100	300	220	180	156	24-2	8x19	166	310	33,20
2130415	125	350	250	210	184	26-2	8x19	188	440	52,00
2130416	150	400	285	240	211	26-2	8x23	217	640	75,20
2130417	200	500	340	295	265	30-2	12x23	275	1100	117,0