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Product overview
The clip check valve is also called countercurrent valve, check valve, back pressure valve and one-way valve. This kind of valve is automatically opened and closed by the force generated by the flow of the medium itself in the pipeline, and belongs to an automatic valve.
Design code
Design criteria: API6D, JB/T8937, API594
Structure Length: API 594, JB/T8937
Connection standards: ASME B16.5, GB/T 9113, JB/T 79, HG/T 20592
Pressure test: API 598, GB/T 13927, JB/T 9092
Pressure-temperature grade: ASME B16.34, GB/T12224
Product characteristics
1. The product has short structure length, small volume and light weight.
2. Sealing valves can be made of soft or hard sealing materials according to different working conditions, with good sealing performance.
3. Horizontal or vertical pipes can be used for easy installation.
4. Disc closure is fast and water hammer pressure is low.
5. The material quality of the parts and the form and size of the end face of the valve can be reasonably selected according to the actual working conditions or user requirements to meet various engineering needs.
Working principle
The function of this type of valve is to allow medium to flow in only one direction and to prevent reverse flow. Usually, the valve operates automatically, and the disc opens under the action of a fluid pressure flowing in one direction. When the fluid flows in the opposite direction, the disc acts on the seat by the fluid pressure and the self-coincidence disc of the disc, thus cutting off the flow.
Among them, stainless steel pair-clip check valve belongs to this type of valve, which includes swing check valve and lift check valve. Swing check valves have a hinged mechanism and a door-like disc that freely rests on the inclined seat surface. In order to ensure that the disc can reach the proper position of the seat surface every time, the disc is designed in a hinge mechanism so that the disc has sufficient swing space and makes the disc truly and comprehensively contact with the seat. Valve discs can be made entirely of metal, or can be metal inlaid with leather, rubber, or synthetic coverage, depending on the performance requirements. When swing check valve is fully opened, the fluid pressure is almost unimpeded, so the pressure drop through the valve is relatively small. The disc of the lift check valve is located on the sealing surface of the seat on the valve body. In addition to the valve disc can rise and fall freely, the rest of the valve is like a globe valve. The fluid pressure causes the disc to rise from the seating surface, and the medium reflux causes the disc to fall back to the seat and cut off the flow. According to service conditions, the disc can be all-metal structure, or it can be in the form of rubber pads or rubber rings embedded on the disc rack. Like globe valves, the passage through which fluid passes through the lift check valve is narrow, so the pressure drop through the lift check valve is larger than that through the swing check valve, and the flow of the swing check valve is limited very little.
Working characteristics
Check valves are characterized by large load variation and small frequency of opening and closing. Once they are put into closed or open state, the application cycle is very long, and the movement of moving parts is not required. But once there is a "switching" requirement, it must be flexible, which is more stringent than the common mechanical movement. Because in most practical applications, the check valve is qualitatively determined to be used for quick closure, and at the moment of the check valve closing, the medium flows in the direction. With the closing of the valve disc, the medium drops rapidly from the maximum reverse flow velocity to zero, while the pressure rises rapidly, that is to say, a "water hammer" which may damage the pipeline system is produced. Phenomenon. The water hammer problem of check valves is more prominent for high-pressure pipeline systems with parallel connection of multiple pumps. Water hammer is a kind of pressure wave in the transient flow of pressure pipeline. It is a hydraulic shock phenomenon caused by the change of fluid velocity in pressure pipeline. The physical reasons are the combination of the incompressibility of fluid, the inertia of fluid motion and the elasticity of pipeline. In order to prevent the hidden danger of water hammer in pipeline, people have adopted some new structures and materials in the design of check valves for many years. While guaranteeing the applicability of check valves, encouraging progress has been made in minimizing the impact force of water hammer. Check valve refers to the valve that automatically opens and closes the disc depending on the flow of the medium itself to prevent medium backflow, also known as check valve, one-way valve, counterflow valve, and back pressure valve. Check valve is an automatic valve. Its main function is to prevent medium backflow, reverse pump and drive motor, and release of container medium. Check valves can also be used in pipelines to supply auxiliary systems where pressure may rise above system pressure. Check valves can be divided into swing check valves (rotating according to the center of gravity) and lift check valves (moving along the axis).
Product use
Check valves are used in pipeline systems. Their main functions are to prevent medium backflow, reverse pumps and their driving motors, and release of medium in containers. Check valves can also be used in pipelines to supply auxiliary systems where the pressure may rise to more than the pressure of the main system. Check valves can be used in pipelines of various media according to different materials. Check valves installed in the pipeline, that is to say, become one of the fluid components of the whole pipeline, and the opening and closing process of the valve disc is affected by the transient flow state of the system where it is located; in turn, the closing characteristics of the valve disc have an effect on the fluid flow state.
