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What is piston type check valve

Author: Site Editor     Publish Time: 2019-02-27      Origin: Site

Piston-type check valves are automatic valves that open under the pressure of fluid in one direction, and the valve flaps to prevent its flow when the fluid flows in the opposite direction. The valve flap of the piston check valve is on the sealing surface of the valve seat, and its valve can be automatically raised and lowered.

List of content for this article:

1. Piston check valve features and installation main matters

2. What is piston type check valve?


Piston check valve features and installation main matters

When working, the pressure of the fluid causes the valve flap to be lifted from the bottom of the valve seat. If the medium returns, the valve flap will return. It is on the valve seat, so the back flow of the fluid is cut off. The valve disc is made of many materials, either metal or rubber. Because the passage of the fluid through the piston check valve is very narrow, the piston check valve is subjected to a higher pressure than the swing check valve.


l  Piston check valve features

(1) small size and light weight;


(2) The piston check valve has simple structure, reliable operation and convenient maintenance. It is widely used in purification equipment, petroleum, chemical and other production operations;


(3) Because of its clever design, it can automatically open and close the valve to prevent back flow of fluid.


(4) The flap of the piston check valve is usually in the shape of a disc and usually rotates around the center of the valve seat. And because it works vertically along the center line of the valve body, it forms a streamlined shape in the passage inside the valve, and its flow resistance is small.


l Piston check valve installation main matters


The piston check valve should be properly installed in accordance with the relevant regulations during installation. The valve should be cleaned before installation to ensure that no damage is received during transportation. If you store for a long time, be sure to check the rust regularly. When installed, it is usually installed on a horizontal pipe with the bonnet facing up. After installation, carefully check the connection between the valve body and the bonnet, whether the nut is tightened, whether there is any damage on the flange, etc.


What is piston type check valve?


The check valve can also be used to supply a line in which the pressure may rise to an auxiliary system that exceeds the system pressure. The check valve can be mainly divided into a swing type check valve (rotation according to the center of gravity) and a lift check valve (moving along the axis).


The function of this type of valve is to only allow the medium to flow in one direction and prevent the direction from flowing. Usually, the valve is automatically operated, and the valve flap is opened by the fluid pressure flowing in one direction; when the fluid flows in the opposite direction, the fluid pressure and the self-reclosing valve flap of the valve disc act on the valve seat to cut off the flow.


Among them, the internal thread check valve and the butterfly check valve belong to this type of valve, and include a swing type check valve and a lift check valve. The swing check valve has a hinge mechanism and a door-like flap that rests freely against the inclined seat surface. In order to ensure that the valve flap can reach the proper position of the valve seat surface each time, the valve flap is designed in the hinge mechanism, so that the valve flap has enough swinging space and the valve flap is truly and comprehensively in contact with the valve seat. The flaps can all be made of metal, or they can be inlaid with leather, rubber, or synthetic coverings depending on the performance requirements. With the swing-open check valve fully open, the fluid pressure is almost unimpeded, so the pressure drop across the valve is relatively small. The valve flap of the lift check valve is located on the valve seat sealing surface of the valve body. In addition to the flap being free to lift and lower, the valve is like a shut-off valve.


The fluid pressure causes the flap to lift from the seat sealing surface. The backflow of the medium causes the flap to fall back onto the seat and shut off the flow. Depending on the conditions of use, the flap can be of all metal construction or it can be in the form of a rubber or rubber ring on the valve disc holder. Like the shut-off valve, the passage of fluid through the lift check valve is also narrow, so the pressure drop through the lift check valve is larger than that of the swing check valve, and the flow rate of the swing check valve is limited. Very few.



The advent of piston check valves has facilitated our industrial production and automatically controls the direction of the fluid to prevent safety incidents.


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