Wafer check valve. Wafer check valve Materials of the main parts of the wafer check valve, double leaf

A check valve is defined as an automatic option that opens when a liquid or gaseous medium is transported through a pipeline in one direction and closes when the flow is reversed. This key part is part of not only the water hydraulic system, but also the heating, sewerage, and also some technological installations of an industrial standard. The shutter is used as a device to level out leakage of household appliances (washing machines and dishwashers).

Locking valves differ in their design, which in turn determines its advantages and scope of operation. The general principle of operation is to open when a given pressure range is reached and close when it drops below the specified range point. Despite the fact that the check valve has a relatively simple design, choosing the right type is of significant importance to ensure the functionality of the entire system.

Purpose and optional principle

The main option for which the water check valve is responsible is the fuse of the water supply main system from emergency pressure drops of the liquid medium transported by the pipeline. The root cause of this phenomenon is the stopping of pumping equipment, which entails negative consequences, such as draining water from the pipe back into the well, unscrewing the pump impeller due to a change in the direction of the acting centrifugal force, which ultimately leads to breakdowns.

The installation of shut-off valves will ensure the correct functioning of a water supply unit for industrial or domestic use and eliminate such phenomena. In addition, the check valve will prevent negative consequences caused by water hammer. The use of this kind of valves in a pipeline system makes it possible to create the correct conditions for efficient and uninterrupted operation of the water supply and drainage lines and pumping equipment, which represent the main part of this system.

The water return valve operates on a simple principle:

1. Water entering this element under a certain pressure influences the shutter, causing the spring to be pressed out, with the help of which the device is in the closed state.
2. After this, the liquid begins to circulate freely in the given direction.
3. In the event that the operating pressure of water in the pipe decreases or the liquid changes its direction, a mechanism with a spring is activated, returning the locking element to the “closed” position.

Since overloads are not excluded in the operation of the hydraulic system, this principle of operation protects against malfunctions in the element base.

When choosing the required model of shut-off valves for industrial or private installations, it is necessary to take into account the requirements of the regulations for such products. The manufacturer describes them in the technical documentation for the pumping station or other type of equipment.

Characteristic features according to which a check valve is selected:

• indications of conditional, test and working pressures to determine the “closed” state;
• values ​​of the seat circumference with the seating surface;
• diameter row of nominal bore;
• ANSI leakage class.

In hydraulic systems, a spring modification safety valve is most often used, with a nominal diameter in the range of 1.5-5 cm. Regardless of the fact that the dimensions of such a device are small, it has a high throughput potential and ensures reliable operation of the water supply system, low vibration and noise levels in installed lines.

The non-return valve used helps reduce the pressure generated by the water pump in the water supply system by 0.25-0.5 Atm. Such indicators make it possible to reduce the load not only on certain components of the hydraulic system, but also on the entire system as a whole.

Equipment and key features of operation

The most popular material for the production of a water reverse valve body is brass. This definition was not made by chance: the alloy is distinguished by a high level of resistance to the aggressive effects of chemical substances (dissolved or coarsely dispersed impurities) found in the liquid passing through the hydraulic system. The concentration of such components varies depending on the installed purification system.

In some models of valves, to level out the negative influence of aggressive factors, a protective chrome or nickel coating is applied to the outer side using the galvanic method.

The design of the locking valve is a small-sized block equipped with a spool, the production of which uses a brass alloy or high-strength plastic. Rubber or silicone washers are used as a seal. The sensing spring mechanism is made of stainless steel. This unit is made up of a spring-loaded element, the compression force of which is changed by a screw.

The check valve operates according to a simple principle, but this is enough to ensure a high degree of reliable operation of the product and its highly efficient use in the hydraulic system. Shut-off valves with a spring are structurally arranged as follows:

• a body made up of parts assembled with each other by means of threads;
• a locking mechanism whose device includes two moving “plate” type spools, mounted on a spindle, and a sealing system that serves to enhance sealing;
• a spring installed between the spool plates and the seat at the outlet of the through hole.

A check valve of this type operates according to a simple scheme:

1. The water flow entering the spring fittings under a given pressure, acting on the spool, helps to expand the spring mechanism.
2. When the spring is compressed, the movable part of the spool moves along the spindle, which helps open the passage channel and release the line of movement of the working medium through the valve.
3. When the intensity of the water flow pressure is reduced or the movement is performed in reverse, the check valve returns the spool to the seat, and the passage hole is closed.

Main varieties

There are many variations in the design of the safety valve. The determination is made based on their optional operating principle, design features and production material. Each of these aspects is determined based on the requirements for the device:

• maximum possible temperature;
• permissible pressure drop;
• minimum and maximum throughput;
• reverse flow speed;
• insulation requirements;
• orientation of the shut-off valves relative to the pipeline.

Clutch model check valve

• plastic rod;
• two spool plates.

Opening and closing of the locking system mechanism during the period when the flow pressure reaches the required range is ensured by a spring device. In turn, based on the type of valve element, a distinction is made between lift, ball, disk and double-leaf check valves.

Lifting coupling valve

The shut-off and control device here is a spool element, the reciprocating movement of which is reproduced at a right angle relative to the axis of the pipeline. The device is lifted (the “open” position) under the pressure of the water flow, and closed when the pressure decreases – under the influence of the weight of the spool, in this case, lowering to its seat. Installation of devices is possible only on vertical pipeline lines.

Double-leaf model

This type of shut-off valve is made up of several segments attached to an axial point located in the center of the flow section. The internal device is located on a spring-loaded mechanism that holds the shutter in the closed state. Due to this feature, it became possible to mount the check valve in any position. Stainless steel or cast iron is used in the production of the body. Recommended for use in pipelines with a cross-section of DU-50 and larger. The transported working environment should not include coarse impurities.

Ball design

The main part of the design is a ball on a spring, which opens the passage channel at the moment of formation of a given pressure of water entering the check valve. Thus, water can move freely, adhering to the required course. When the pressure drops or fluid rushes in the opposite direction, the spring mechanism reverses the ball back to its seat.

Check valve with butterfly valve

Such devices use a pair of spring-loaded disks. By applying the working pressure to the clamping mechanism, the spiral is pressed out, freeing the channel. After the pressure intensity is recorded as reduced, the sash is independently pressed against the seat, and accordingly, the flow is blocked. Among the advantages noted:

• small dimensions;
• low weight due to the absence of flanges;
• Possibility of installation on vertical, horizontal surfaces and at an angle;
• simple installation process.

With brass spool

A characteristic feature of the safety valve is a spherical spool chamber located inside its brass body. Thanks to the design format, it was possible to increase the useful volume of the spool compartment and improve throughput. Structurally, the check valve is made up of the following parts:

• nickel-plated brass body;
• movable spool;
• spring;
• brass spool plates;
• EPDM gasket.

Check valve with drain and air vent

Universal valve systems are used to equip pipelines operating at operating temperatures in the range from –20 to +90 °C. This approach makes it possible to significantly simplify installation work and maintenance of both individual parts and the entire system. In addition, a high level of reliability is achieved by reducing the overall hydraulic pressure and reducing the number of installation transitions.

The shut-off and control valves are equipped with two pipes: the first plays the role of an adapter for installing an air vent, the second is used as a device for collecting and removing accumulated condensate. The air outlet pipe is equipped with an internal thread and is located on the housing above the receiving compartment of the spool. To release excess atmospheres from the system, it is advisable to install a Mayevsky tap. The second section of pipe, located at the outlet of the valve, is designed to drain excess water formed as condensate by the valve device.

When the water check valve is positioned horizontally, an air vent is not required; a pressure measuring device is mounted in its area; when vertical, the drainage pipe is used to grind off excess moisture, and the second section of the tube with an air vent is used to remove air pockets. For these reasons, it is worth carefully considering the purpose for which a combination check valve is purchased and whether its functionality is suitable for the specific parameters of the hydraulic system. The body in such models is made of brass with nickel galvanizing. The minimum value of the opening pressure difference is 0.025, closing pressure is 0.05 bar.

Spring check valve with polypropylene body

A fitting with a propylene body is similar in appearance to an oblique elbow. It is used in water supply systems made of polypropylene pipes. Shut-off valves are connected to the nozzles using polyfusion butt welding, which is a high-quality connection method by heating the edges of the material and fastening them under pressure.

Despite the fact that the connections are non-separable, ease of maintenance is ensured due to the seat and spool removed from the perpendicular plane of the spool chamber. Thus, the check valve has an additional outlet, which provides easy access to the locking mechanism for cleaning, routine inspection or repair, without compromising the integrity of not only the body, but also the system as a whole.

Other types of water check valves

In the main pipeline circuit of centralized water supply and industrial devices, such types of valves as petal, ball and wafer are installed.

Reed (gravity) type check valve

They are equipped with a spring-loaded rotary mechanism and are less sensitive to contaminated working environments. Under the pressurized pressure, the spool is tilted, thereby providing free access for transporting liquid through the pipes. A reduced pressure to the set range provokes a drop in the spool and, accordingly, the closure of the channel.

There are 2 main types of gravitational mechanisms:

1. Simple - used for highways whose operating capacity is not subject to shock phenomena. Relevant for installation on pipes whose diameter does not exceed 40 cm.
2. Non-impact check valve - equipped with a device that provides smoothing or a smoother process of returning to the spool seat. This design allows the model to be mounted on large diameter pipes.

Ball check valve

Ball devices are distinguished by the presence of a spring-loaded ball as an actuator. The production of this element uses rubber, aluminum, or both materials simultaneously. When the spring is triggered due to a change in the direction of the water flow, the ball closes the cross-section of the passage and falls into its seat. It is located under the top cover and moves along the channel with an angle.

Wafer check valve

The advantages provided by water check valves belonging to the wafer category include:

• small size, which allows them to be used in cramped conditions;
• reducing the length and other parameters of the installed pipeline diagram reduces the overall cost of the system.

Among the most common modifications, differing in technical characteristics, are:

• 19S53NZH – devices that are easy to maintain and operate;
• 16Ch42R – check valve made of particularly durable material;
• RU16 is a model characterized by a high degree of reliability of the connection formed, using tie rods.

Check valve: materials of manufacture

For the production of shut-off valves, a full arsenal of modern technologies is used. The emergence of new materials and the application of the capabilities of previous materials make it possible to increase the operational potential of the device. Depending on the material used in manufacturing, safety valve bodies are distinguished from:

1. Brass - the material is not susceptible to corrosion. The valves are relevant in domestic and industrial conditions for installation on pipelines of any type. They do not require regular inspection and maintenance.
2. Check valve made of cast iron (grey, malleable). The use of this category is limited due to the tendency to rust and deposits. They are mounted on large-diameter pipes in a centralized main.
3. Of stainless steel. A check valve of this type is the most reliable, but also the most expensive. They practically do not corrode, and the inside does not accumulate harmful deposits.
4. Combined materials. This modification can include various polymer alloys: copper, nickel, niobium, etc.
5. Non-metallic. Made from plastic, ceramics, etc.

A check valve operating in a circuit with a small pressure drop is selected with a seat made of cast iron or aluminum alloy; if high system loads are expected, it is made of steel.

In household systems, a brass coupling locking mechanism is used, which is highly reliable and affordable. It is installed after meters that record water consumption. This eliminates the problem of reverse scrolling. Installation on separate sections of the pipeline system is possible, while providing protection against complete emptying when water is drained or the pumping equipment responsible for its supply is stopped.

When deciding on the necessary modification, you will first need to familiarize yourself with the technical parameters of the shut-off valves and compare them with the performance indicators of the pipeline. The check valve for water is selected based on the pressure in the pipes when transporting the flow of technical or drinking working fluid. In addition, the diameter of the pipes on which the valve is supposed to be installed, the connection method (determined simultaneously with the design of all system connectors) and the material of manufacture are taken into account. Taking into account all these indicators, you can choose a protective mechanism whose operation will be reliable and long-lasting.

1. Installation and operation of the product.
   • Mandatory " "
   • Only persons who have studied this documentation and have been instructed in compliance with safety regulations are allowed to install and operate the product.
   • Before installation begins, it is necessary to inspect the product.
   • If damage or defects resulting from improper transportation or storage are detected, putting the product into operation without agreement with the seller is not allowed.
2. Installation conditions.
   • The check valve is not intended to be used as a shut-off valve. Tightness class - B according to GOST 54808-2011
   • In most cases, a spring check valve cannot operate in conditions of strong and frequently pulsating flows (for example, immediately behind a piston compressor)
   • It is not allowed to use check valves with operating parameters different from those specified in the technical documentation
   • Before starting operation, the pipeline must be purged to remove scale and dirt.
   • The alignment of the pipeline and the distance between the flanges should be within 3-5 mm of the ideal so that during installation the valve is not subject to excessive mechanical stress.
   • The valve can be installed on vertical, inclined and horizontal sections of the pipeline, in accordance with the instructions on permitted and prohibited installation positions (installation on a vertical and inclined section of the pipeline with the flow direction "top-down" is extremely undesirable for this type of valve):
     
   • The valve is installed on the pipeline so that the arrow on its body coincides with the direction of movement of the medium, and, to ensure uniform wear during operation, no closer than 3-5 diameters before or after the narrowing / turning of the pipe.
     
     
   • Preferred installation position on an inclined or vertical pipeline with water flowing from bottom to top.
   • On a horizontal section, it is advisable to install the valve in such a way that the valve axis (stem) is installed at an angle of 45 degrees to the vertical (horizontal).
   • It is not advisable to install a valve on a pipeline bend, but if you have to, you should install it after the bend along the flow and orient the valve axis along the bend radius:
     
   • It is required to provide sufficient space around the check valve for future maintenance work.
   • The medium flow must be directed in the direction of the arrow on the valve body.
   • Before installation, the sealing surfaces of the check valve and connecting flanges must be thoroughly cleaned.
   • The fastening bolts must be tightened evenly
   • After starting the system, make sure there are no leaks at the connection points
   • Remember to check for leaks after several hours of operation
3. terms of Use .
   • Check valves ABRA-D-122-EN do not require constant maintenance
   • Periodically inspect the valve for media leaks.
   • 
     Attention!
   • Do not touch the working product as the surfaces may heat up.
   • Before starting maintenance or dismantling, make sure that the product is not under pressure or at high temperatures.
   • Do not remove the label containing the markings and serial number from the product.
   • Check valves must be checked regularly, especially those that do not operate constantly, for leaks through the seals.
4. Transportation and storage conditions .
   • Storage and transportation should be carried out without shock loads at temperatures: -40...+65 °C.
   • Do not allow foreign objects to get inside or the product to fall
   • The valve can be checked when replacing pipelines
   • The product must be stored in an uncontaminated area and protected from exposure to precipitation
   • During transportation, the product body must be protected from damage.
5. Estimated service life. Warranty.
   • The estimated service life is at least 50 years, when used on water in accordance with SanPiN 2.1.4.1074-01 and GOST 2874-82 without mechanical damage to the integrity of the protective coating in the temperature range corresponding to the technical data sheet, installation and operating instructions and catalogs.
   • The warranty period, subject to the consumer's compliance with the rules of transportation, storage, installation and operation, is 12 months from the date of commissioning, but not more than 18 months from the date of sale. Provided that all requirements for the estimated service life are met, the warranty period is at least 10 years
   • All issues related to warranty obligations are provided by the selling company

In any systems whose design includes a pipeline, it is provided that the working fluid is transported in one direction. In order not to encounter a change in the direction of its movement, which can lead to failure of the entire system, various technical devices are used, one of which is a wafer check valve. It is equipped with pipelines used by oil refining and chemical industry enterprises, through which both liquid and gaseous working media are transported.

Wafer check valve - “flap” made of stainless steel for use in various aquatic environments

Design features and characteristics

A wafer valve, like all check valves, is used to block the flow of a gas or liquid if it begins to move in the wrong direction. In other words, it is a kind of locking device. Wafer check valves, unlike many others, can be installed in both horizontal and vertical positions. Depending on the features of their design, they can be:

1. spring;
2. pneumatic, made of stainless steel;
3. double-leaf couplings made of cast iron;
4. rotary type, made of stainless steel.

The installation process for wafer valves of all the above categories is the same and does not cause any particular difficulties.

Among the advantages that check valves of the wafer type have, it should be noted their compact dimensions, which makes it possible to use them in cramped conditions where it is not possible to use other valve products. Thanks to the use of such compact valves, it is possible to reduce the length and other parameters of the installed system, which is important in many situations.

There are several most common modifications of wafer check valves, each of which differs in certain technical characteristics. So, if we talk about models of such devices, among them we should highlight:

• 19С53Нж - devices that are easy to operate and maintain;
• 16Ch42R – wafer type check valves, which are made of especially durable materials;
• RU16 are models that are characterized by high reliability of the connection created with their help.

Main varieties

If we review the most popular check valve devices, we should start with rotary models, in particular with the DN150 wafer valve. DU150, like other models, allows the flow of the working medium through itself in only one direction. If the direction of movement of the working fluid flow changes, the valve is automatically blocked and its shutter is closed.

Among the check valves belonging to the class of rotary valves, there are:

• simple;
• unstressed.

The locking element of rotary-type check valves is a spool, which allows them to be used even when working with heavily contaminated working media. In addition, the design features of such valve devices make it possible to use them for pipelines of even significant diameter (from fifty to one hundred and fifty millimeters).

Rotary check valves, the structural elements of which are made of brass, are used to equip heating systems, as well as water and heat supply systems. The design of such valves, which operate primarily with a liquid working medium, includes a mesh that acts as a filter element.

Depending on their design, rotary check valves can be one of three types:

• coupling;
• flanged;
• wafer

Wafer devices, in turn, are divided into check valves of the following types:

• reverse wafer valve made of stainless steel;
• double-leaf type wafer check valve;
• check wafer valves made of cast iron.

Popular models of check valve wafer devices, for the manufacture of which steel alloys are used, are also DN25, 32, 50, 80, 110. The most significant advantages of these valve devices are compact dimensions and affordable cost. Meanwhile, when using wafer valves in a pipeline, a significant loss of pressure of the transported working medium occurs.

Among the many check valves offered by modern manufacturers, we should highlight the DU150 flange lift valve and the DU100 model, which are installed and successfully used on pipelines for various purposes. Mention should also be made of a brass wafer check valve with two flaps mounted on the same axis. Valve devices of this type, characterized by unpretentious installation, are used to equip pipelines whose diameter is in the range of 50–80 mm.

Based on the material of manufacture, flanged valve devices are divided into the following types of products:

• wafer-type steel check valve with protective mesh;
• cast iron check valve, also equipped with a mesh that acts as a filter element.

Valves made of cast iron or steel alloy are large in size and weight, which somewhat limits their scope of application.

In order not to significantly lose pressure in the working medium transported through the pipeline, it can be equipped with spring-type check valves, which can be made of either cast iron or brass alloy. Flanged check valves are also equipped with a spring, the most popular models of which include DN50, 80, 110. Their great advantage is that they can be installed in both horizontal and vertical positions. In addition, wafer spring check valves can successfully withstand such phenomena as water hammer.

Closing of the valve in check valves that are not equipped with a spring is ensured by the force of gravity that the valve itself has. Their installation can be carried out both horizontally and vertically, but only if the flow of the working medium transported through a vertical pipeline is directed from bottom to top.

Today, ventilation systems are also equipped with reverse air seals, which is necessary in order to prevent contaminated air from entering back into the ventilated room. Such devices can be found in ventilation systems serving not only industrial premises, but also office and domestic premises (kitchens, sanitary facilities, etc.). In addition, ventilation systems installed in public buildings – shopping and entertainment centers, shopping malls, etc. – are equipped with check valves.

The design of check valves installed in ventilation systems is formed by a rotating axis on which special blades are fixed. These blades can cut off the air flow due to a special spring or gravity.

Another type of such devices is a poppet (or disk) check valve, the closing element of which is a disk located in a seat with a sealing element. The shut-off element in the disc check valve is fixed on a rod that can move freely in the device body. The disc type check valve can be wafer or coupling. It is used to equip both pipelines through which gaseous working media are transported and ventilation systems.

Check valve modifications and manufacturers

Among the popular manufacturers of check valve devices are the following companies:

• Tecofi (France);
• FAF (Türkiye);
• FERRO (Poland);
• Westshintorg (Republic of Belarus).

If we talk about the most popular models, they are valves DN32, 50, 80, produced by the French company Tecofi. These models, which are made from stainless steel, are distinguished by their practicality, high reliability and long service life, which makes them so popular among domestic consumers.

The main parameters that influence the cost of reverse valve devices are:

1. appointment;
2. design;
3. material of manufacture;
4. valve dimensions and cross-section of its mounting holes.

A brief overview of the main technical characteristics of the most popular models of check valves will give an opportunity to get an idea of ​​these devices.

The body of the check valve of this model (16CH42R) is made of cast iron, and its shutter part is made of brass. Thanks to the manufacture of the DN50 valve part from stainless material, it can be used to equip pipelines through which water and steam are transported. The check valve of this model can operate at a temperature of the working medium exceeding 225° and at a pressure of 1.6 MPa.

Such a check valve is installed on both horizontal and vertical pipelines. At the same time, on vertical pipelines it is located with the inlet pipe down, and on horizontal pipelines the axis of rotation of its flaps should be in the horizontal plane.

The DU80 wafer type check valve, the body of which is made of galvanized steel or cast iron, and the sealing element is made of rubber, can be used for installation on pipelines through which hot and cold water is transported. The maximum temperature of the working medium that the DU80 can withstand is +90°, and the maximum pressure is 1.6 MPa.

This disc type check valve has elements made of galvanized steel. DU100 can be used in pipelines through which cold and hot water and steam are transported; it can withstand a pressure of 1.6 MPa and a temperature of +130°.

The body of the wafer check valve of this model, used to equip pipelines for various purposes, is made of cast iron, and the shut-off elements, which are two spring-loaded flaps, are made of stainless steel. DU150 is also used to equip pipelines through which petroleum products are transported, and can be installed in both horizontal and vertical positions. The operating pressure at which the check valve of this model can be operated is 1.6 MPa.

As mentioned above, check valves, depending on their design, can be installed on both horizontal and vertical sections of pipelines. Thus, coupling-type check valves are used on horizontal sections of pipelines, and shut-off devices, the fastening element of which is a flange, are used on vertical sections.

The process of installing a check valve (for example, in a sewer system) occurs in the following sequence:

1. The pipe section on which the check valve will be installed is selected. Such an area must be open for further maintenance and is usually located before the sewer riser.
2. When installing a check valve in an existing sewer system, care should be taken to ensure that the dimensions of the pipes do not exceed the dimensions of the valve device.
3. When installing the valve, you must pay attention to the arrow on its body, which indicates the direction of flow of the transported medium.
4. The fixation method is selected depending on the design of the product.
5. After installing the check valve, check the tightness of all connections made.

Wafer check valve installation diagram

The correct operation, reliability and durability of the entire pipeline system depend on how correctly all the above steps are performed.