Stainless steel check valve refers to a valve that automatically opens and closes the valve disc based on the flow of the medium itself, which is used to prevent medium backflow. It is also known as a check valve, one-way valve, backflow valve, and backpressure valve. Stainless steel check valve is an automatic valve, and its main function is to prevent medium backflow, prevent pump and drive motor reverse rotation, and discharge the container medium.
1. To prevent reverse flow of the medium, stainless steel check valves should be installed on equipment, devices, and pipelines;

2. Stainless steel check valves are generally suitable for cleaning media and are not suitable for media containing solid particles and high viscosity;

3. Horizontal lifting stainless steel check valves should be used on horizontal pipelines with a nominal diameter of 50mm;

4. The straight through lifting stainless steel check valve can only be installed in horizontal pipelines;

5. For the inlet pipeline of the water pump, it is advisable to choose a bottom valve. The bottom valve is usually only installed on the vertical pipeline of the pump inlet, and the medium flows from bottom to top;

6. The lifting type has better sealing performance and greater fluid resistance compared to the swing type. It is recommended to install the horizontal type on a horizontal pipeline and the vertical type on a vertical pipeline;

7. The installation position of the swing type stainless steel check valve is not limited. It can be installed on horizontal, vertical, or inclined pipelines. If installed on vertical pipelines, the medium flow direction should be from bottom to top;

8. The swing type stainless steel check valve should not be made into a small diameter valve, but can be made into a high working pressure. The nominal pressure can reach 42MPa, and the nominal diameter can also be large, with a maximum of 2000mm or more. It can be suitable for any working medium and any working temperature range depending on the material of the shell and sealing parts. The medium is water, steam, gas, corrosive medium, oil, medicine, etc The working temperature range of the medium is between -196-800 ℃;

9. The swing type stainless steel check valve is suitable for low pressure and large caliber applications, and the installation situation is limited;

10. The installation position of butterfly stainless steel check valves is not limited and can be installed on horizontal pipelines, as well as vertical or inclined pipelines.

Structural principle of stainless steel check valve:
When the swing stainless steel check valve is fully opened, the fluid pressure is almost unobstructed, so the pressure drop through the valve is relatively small. The valve disc of the lift stainless steel check valve is located on the sealing surface of the valve seat on the valve body. Except for the valve disc that can be freely lifted and lowered, the rest of the valve is like a globe valve. The fluid pressure lifts the valve disc from the sealing surface of the valve seat, and the medium reflux causes the valve disc to fall back onto the valve seat, And cut off the flow. According to the usage conditions, the valve disc can be an all metal structure, or it can be in the form of embedded rubber pads or rubber rings on the valve disc holder. Like globe valves, the passage of fluid through the lifting stainless steel check valve is also narrow. Therefore, the pressure drop through the lifting stainless steel check valve is greater than that of the swing stainless steel check valve, and the flow rate of the swing stainless steel check valve is limited very little.

1、 Swing type stainless steel check valve: The valve disc of the swing type stainless steel check valve is in a disc shape and rotates around the axis of the valve seat channel. Due to the streamlined channel inside the valve, the flow resistance is smaller than that of the lift type stainless steel check valve. It is suitable for large diameter fields with low flow rates and infrequent flow changes, but not suitable for pulsating flow. Its sealing performance is not as good as that of the lift type. Swing type stainless steel check valves are divided into three types: single disc type, double disc type, and multi half type, These three forms are mainly divided by valve diameter to prevent hydraulic shock when the medium stops flowing or flows backwards

2、 Lift type stainless steel check valve: A stainless steel check valve with a valve disc sliding along the vertical centerline of the valve body. Lift type stainless steel check valves can only be installed in horizontal pipelines, and the disc can be used as a ball on high-pressure small diameter stainless steel check valves. The valve body shape of lift type stainless steel check valves is the same as that of globe valves (can be used with globe valves), so their fluid resistance coefficient is relatively large. Its structure is similar to that of globe valves, The valve body and valve disc are the same as the globe valve. The upper part of the valve disc and the lower part of the valve cover are equipped with guide sleeves, which can freely rise and fall within the valve disc guide. When the medium flows downstream, the valve disc opens by the medium thrust. When the medium stops flowing, the valve disc falls vertically on the valve seat, playing a role in blocking the reverse flow of the medium. The direction of the medium inlet and outlet channels of the straight through lifting stainless steel check valve is perpendicular to the direction of the valve seat channel; The vertical lifting stainless steel check valve has a medium inlet and outlet channel in the same direction as the valve seat channel, and its flow resistance is smaller than that of the straight through type

3、 Disc type stainless steel check valve: A stainless steel check valve with a disc rotating around the pin inside the valve seat. The disc type stainless steel check valve has a simple structure and can only be installed in horizontal pipelines, resulting in poor sealing performance

4、 Pipeline type stainless steel check valve: A valve with a disc sliding along the center line of the valve body. Pipeline type stainless steel check valve is a newly emerging valve with small volume, light weight, and good processing technology. It is one of the development directions of stainless steel check valves. However, the fluid resistance coefficient is slightly larger than that of swing type stainless steel check valves

5、 Compression type stainless steel check valve: This valve is used as a boiler feed water and steam shut-off valve, which has the comprehensive function of a lift type stainless steel check valve and a globe or angle valve.

In addition, there are also some stainless steel check valves that are not suitable for pump outlet installation, such as bottom valves, spring type, Y-type, etc