How does a check valve work, and what are the functions of a check valve?

Check valves. The working principle is to allow the medium to flow in only one direction and prevent it from flowing in the opposite direction. Usually this kind of valve works automatically, and the disc opens under the action of fluid pressure flowing in one direction; When the fluid flows in the opposite direction, the fluid pressure and the self-closing disc of the disc act on the valve seat, thus cutting off the flow.

The check valve is used in the occasion that the air flow is not allowed to flow in the opposite direction, such as when the air compressor fills the air tank, a check valve is arranged between the air compressor and the air tank, and when the air compressor stops working, the compressed air in the air tank can be prevented from flowing back to the air compressor. Check valves are also often used with throttle valves.

Sequential valves are combined into one-way throttle valves and one-way sequential valves.

The check valve is an automatic valve, and its main function is to prevent the backflow of the medium, prevent the pump and the drive motor from reversing, and the discharge of the container medium. Check valves can also be used on lines that supply auxiliary systems where pressure may rise above the system pressure. Check valves can be mainly divided into swing-open check valves (rotating according to the center of gravity) and lifting check valves (moving along the axis).

The air flow can only flow in one direction and not in the opposite direction.

A check valve is a directional control valve where the air flow can only flow in one direction and cannot flow in the opposite direction. It works on the same principle as a hydraulic check valve. Compressed air enters from the P port, overcomes the spring force and friction force to open the check valve port, and the compressed air flows from P to A; When there is no compressed air at the P port, under the action of the spring force and the residual air force of the A port (cavity); The valve port is closed, blocking the airflow from A to P.

The check valve is used in the occasion that the air flow is not allowed to flow in the opposite direction, such as when the air compressor fills the air tank, a check valve is arranged between the air compressor and the air tank, and when the air compressor stops working, the compressed air in the air tank can be prevented from flowing back to the air compressor. Check valves are also often combined with throttle valves, sequence valves, etc. to form one-way throttle valves, one-way sequential valves.

Physical explanation: the working principle of hydraulic check valve.

The role of the check valve in the hydraulic system is as follows:

1) If the check valve is installed at the outlet of the pump, it can prevent the pressure of the system from rising suddenly and damaging the oil pump, that is, it will play a non-return role.

2) If the check valve is connected in parallel with the throttle valve or pressure reducing valve, it can form an actuator with a forward slow speed and a fast reverse speed; Or forward deceleration, reverse free flow loop.

3) If the check valve and the pressure valve are connected in series, the adjustment pressure can be gradually increased to prevent the reaction of the pressure.

4) For the hydraulic control check valve, the control oil circuit can be used to open the check valve to achieve the purpose of making the oil flow in the opposite direction.

There are two types of check valves: straight-through and right-angle. Straight-through check valves are threaded and mounted on the pipeline. There are three types of right-angle check valves: threaded connection, plate connection and flange connection.

A hydraulically controlled check valve, also known as a latching valve or pressure holding valve, is the same as a check valve and is used to prevent the reverse flow of oil.

However, when the oil flow needs to flow in the reverse direction in the hydraulic circuit, the oil pressure can be controlled and the check valve can be opened to make the oil flow flow in both directions. The hydraulically controlled check valve has a tapered spool, so it has good sealing performance.

When the oil circuit is required to be closed, this valve can be used as a one-way lock of the oil circuit to maintain pressure. There are two types of leakage control oil leakage methods for hydraulic control check valves: internal leakage type and leakage type. In the oil circuit without back pressure at the reverse outlet of the oil flow, the internal leakage type can be used; Otherwise, it is necessary to use the leak type to reduce the control oil pressure.

The 8 functions of a check valve:

1. It can prevent the reversal of the drive shaft of the hydraulic pump when the load drops;

2. Reverse free flow of throttle valve (one-way throttle valve);

3. It is used as a filling valve for the press;

4. It is used as an anti-cavitation valve for rotating inertial load;

5. Used as a bypass valve when the oil suction filter is blocked, δp< bar;

6. Used as a bypass valve when the oil return oil filter is blocked, δp 1 3bar;

7. Bridge flow control valve (to ensure that one direction passes through the flow valve);

8. It is used for the oil supply circuit of the closed system.

(1) The function of the ordinary check valve is to make the oil flow only in one direction, and reverse flow is not allowed.

2) Its purpose is: installed at the outlet of the pump, can prevent the impact of system pressure impact on the pump, in addition, when the pump is not working, can prevent the system oil from flowing back to the oil tank through the pump, check valve can also be used to separate the oil circuit, to prevent interference. Check valves can be combined with other valves to form a composite valve.

The working principle of a hydraulically controlled check valve is a valve that can make the check valve flow in reverse by controlling the fluid pressure. This kind of valve occupies an important position in the hydraulic support equipment of coal mining machinery. The difference between the hydraulic check valve and the ordinary check valve is that there is an additional control oil circuit K, when the control oil circuit is not connected to the pressure oil, the hydraulic check valve works like an ordinary check valve, and the pressure oil only flows from the oil inlet to the oil outlet, and cannot flow in reverse.

When the control oil circuit oil controls the pressure input, the piston ejector rod moves to the right under the action of pressure oil, and the check valve is opened with the ejector rod to make the inlet and outlet oil ports connected. If the outlet is larger than the inlet, the oil will flow in the opposite direction.

Check valves. How it works:Compressed empty-handed bypass air enters through the p-port to overcome spring force and friction.

The check valve port is opened, and the compressed air flows from P to A; When there is no compressed air at the P port, under the action of spring force and residual air force at the A port; The valve port is closed, blocking the airflow from A to P.

The check valve is used in the occasion that the air flow is not allowed to flow in the opposite direction, such as when the air compressor fills the air tank, a check valve is arranged between the air compressor and the air tank, and when the air compressor stops working, the compressed air in the air tank can be prevented from flowing back to the air compressor.

Check valves are used in hydraulic systems.

or in pneumatic systems to prevent the reverse flow of compressed air. There are two types of check valves: straight-through and right-angle. Straight-through check valves are threaded.

Installed on the pipeline. Right angle check valves are available with threaded, plate and flanged connections.

Three forms. <>

When installing the check valve, special attention should be paid to the flow direction of the medium, the normal flow direction of the medium should be consistent with the direction of the arrow indicated on the valve body, otherwise the normal flow of the medium will be cut off, and the bottom valve should be installed at the bottom of the suction pipeline of the pump.

When the check valve closes the rough ruler, it will produce water hammer pressure in the pipeline, which will cause damage to the valve, pipeline stool rubber or equipment in serious cases, especially for large-mouth pipelines or high-pressure pipelines, so it should attract the attention of the check valve selector.

The one-way valve is only used to prevent the reverse flow of fluid media in various pipelines or equipment.

Check valves are used in many industries, and the roles they play will be different, but many people don't know much about check valves and their functions, so what are the functions of check valves? Let's give you a detailed introduction to the relevant knowledge content.

1. Check valve, also known as check valve or check valve, is a kind of valve that allows the fluid to flow only in one direction and cannot reverse the flow phenomenon. If the check valve is used in the hydraulic system, the oil flow can be prevented from flowing in the opposite direction. If the check valve is used in a pneumatic system, it is possible to avoid the phenomenon of reverse flow when compressing the air.

2. If it is an ordinary check valve, then there is only one function, which is to let the oil only flow in one direction, and not in the opposite direction. If the check valve is installed at the outlet of the pump, it can avoid damage to the pump when the pressure in the system suddenly rises.

3. When the pump is not working, the check valve can also avoid the backflow of the oil in the system and flow back to the mailbox. The check valve can also play the role of separating the oil circuits to avoid mutual interference between the oil circuits. When a check valve is combined with other valves, it can be combined to form a combination valve.

4. If the check valve and the throttle valve or pressure reducing valve are connected in parallel, the actuator can be formed, so that the fluid can flow slowly when it is in the forward direction and fast flow when it is in the reverse direction. In other cases, it can be slowed down when it is in the forward direction, and free flow loop is performed in the reverse direction.

5. If the check valve and the pressure valve are connected in series, the pressure can be slowly increased and adjusted to avoid the reaction of the pressure. If the check valve is classified according to the structure, it can generally be divided into three types, namely: lifting check valve, swing check valve, and butterfly check valve.

If the structure is different, the function of the check valve will also be different, so you should choose the appropriate check valve according to the installation environment and your own needs.

The above is the detailed content of the function of the check valve introduced to you today, I hope it can help you understand the check valve better. There are many types of check valves on the market, and you should choose the right check valve according to the installation environment and your own needs.

The check valve automatically opens and closes through the flow of the medium itself, so as to prevent the reverse flow of the medium. In general, the installation method of single-bush tung valve is up in and down out, which is not only widely used in heat pump air conditioners, but also often installed in the position of compressor exhaust port. 1. Install a check valve at the outlet position of the pump.

It can avoid damage to the oil pump caused by the pressure rise of the system, so as to play the role of non-return. If the check valve and the pressure reducing valve are installed in parallel to install lead seepage, it can play the role of forward deceleration and reverse fast.

2. In addition, the check valve can also be connected in series with the pressure valve, and the pressure can be adjusted and increased after series connection, so as to avoid the situation of pressure reaction. In the case of a hydraulically controlled check valve, the check valve can be opened by controlling the oil circuit, so that the oil can flow in the opposite direction.

3. However, in the process of using the check valve, it is necessary to ensure that the control pressure of the hydraulic check valve is sufficient, and the control pressure must not be lost, and check whether the control pressure is consistent with the requirements of the reverse start of the check valve, otherwise it is easy to cause the check valve to be unable to use normally.

Abstract:The check valve is composed of three parts: valve body, valve core and spring, when working, the medium enters the valve body through the inlet of the check valve, when the medium flows in the specified direction, the valve disc is opened by the action of the medium force, and the medium can pass through normally; In the case of reverse flow, the disc closes under the action of its own weight and the reverse force of the medium, preventing the reverse flow. Due to this principle, the check valve will have a certain impact on the water pressure and flow rate of the medium, but the effect is almost negligible when the valve is selected with the right size.

Let's take a look at the structure and principle of the check valve. 1. What is the working principle of the check valve?

Check valve, as the name suggests, is a valve that only allows one-way flow, which can prevent backflow and backflow, so it is also called check valve and check valve, which is often used in hydraulic systems, pneumatic systems and other industrial purposes, so what is the principle of one-way valves?

1. Check valve structure.

The structure of the check valve is relatively simple, mainly composed of three parts: valve body, valve core and spring, and the inlet and outlet on both sides are connected with the pipeline through joints.

2. The principle of check valve.

The check valve only allows the medium to pass in one direction and closes completely in the opposite direction. When air pressure is added to the left side, the air pressure acting on the spool overcomes the spring force and friction force, opens the spool, and connects the inlet and outlet medium. The flow of the medium from the left side to the right side is called forward flow, in order to ensure the stable flow of the medium from the inlet to the outlet, a certain pressure difference should be maintained between the inlet and outlet, so that the check valve is kept in the open position.

2. Does the check valve affect the water pressure and flow rate?

According to the working principle of the check valve, it can be seen that the one-way Lizhou Xun valve has the effect of preventing the reverse flow of the medium entering the inside, but at the same time, the check valve will also have a certain impact on the water pressure of the internal medium.

1. The influence of check valve on flow rate.

The check valve will prevent the reverse flow of the medium through the valve disc, so how much will affect the flow of the medium, the specific impact depends on the size of the inner diameter of the check valve, if the rated flow rate of the check valve and the flow rate you need are consistent, the impact can be small to negligible; However, if the check valve is not suitable for the vertical mark, it may have a large impact on the flow rate.

2. The influence of check valve on water pressure.

The pressure difference generated by the flow through the check valve has a certain relationship with the opening pressure of the check valve, and the effect on the water pressure is relatively small when using a check valve with the appropriate specifications, unless the pressure of the system is too small. If it is found that the check valve reduces the water pressure, it can be solved by the following two methods: one is to increase the pressure in front of the check valve, which is relatively simple, but not economical; It is more economical to change the structure of the check valve, that is, to choose a check valve with a small pressure drop.