Flange Stainless steel Check valve
Lift type check valve
GB/T12235 design, bolted valve bonnet, lifting valve disc
Overview
Check valve refers to a valve whose opening and closing parts are circular discs and rely on their own weight and medium pressure to act to block the reverse flow of the medium. It belongs to the automatic valve category, also known as check valve, one-way valve, return valve or isolation valve. The movement mode of the valve disc is divided into lifting type and swing type. The structure of the lift check valve is similar to that of the globe valve, except that it lacks the valve stem that drives the valve disc. The medium flows in from the inlet end (lower side) and flows out from the outlet end (upper side). When the inlet pressure is greater than the sum of the weight of the valve disc and its flow resistance, the valve is opened. On the contrary, the valve is closed when the medium flows back. The swing check valve has an inclined disc that can rotate around its axis, and its working principle is similar to that of the lift check valve. Check valves are often used as foot valves in water pumping devices to prevent the backflow of water. Check valves and stop valves are used in combination to provide safe isolation. The disadvantage is that the resistance is large and the sealing is poor when closed.
Selection standards for check valves
1. In order to prevent the backflow of the medium, check valves should be installed on equipment, devices and pipelines;
2. Check valves are generally suitable for clean media and are not suitable for media containing solid particles and high viscosity;
3. Generally, horizontal lift check valves should be used on horizontal pipelines with a nominal diameter of 50mm;
4. The straight-through lift check valve can only be installed on horizontal pipelines;
5. For the water pump inlet pipeline, a bottom valve should be used. The bottom valve is generally only installed on the vertical pipe at the pump inlet, and the medium flows from bottom to top;
6. The lifting type has better sealing and greater fluid resistance than the swing type. The horizontal type should be installed on horizontal pipes, and the vertical type should be installed on vertical pipes;
7. The installation position of the swing check valve is not restricted. It can be installed on horizontal, vertical or inclined pipelines. If it is installed on a vertical pipeline, the medium flow direction must be from bottom to top;
8. The swing check valve should not be made into a small-diameter valve. It can be made into a very high working pressure. The nominal pressure can reach 42MPa, and the nominal diameter can also be very large, up to 2000mm or more. Depending on the materials of the shell and seals, it can be applied to any working medium and any working temperature range. 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 check valve is suitable for low pressure and large diameter, and the installation location is limited;
10. The installation position of the butterfly check valve is not restricted and can be installed on horizontal pipelines, or on vertical or inclined pipelines;
Product display
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