The check valve features a design with high inlet and low outlet for optimal performance
Thread Content
The conventional approach is to use a low inlet and high outlet, but in some cases a high inlet and low outlet is used; or it depends on the appropriate situation for its application! High in, low out applies to high-pressure valves; in this case, the torque required to close the valve stem is much smaller than that needed for low in, high out operation. With only the force of the medium acting, there is no sealing force involved, making sealing easier. The only downside is that the filler is under stress when closed, making it prone to damage. Is there also a requirement for this in the manufacturing process?
There is a possibility that the valve plug will need to be pulled out when opening it
When the pressure difference is large, using a low-inlet and high-outlet configuration makes cavitation more likely to occur; even with specially designed valve cores and seat structures, the sealing surfaces can still be damaged. Using a high-inlet and low-outlet configuration helps to avoid such problems. The process generally does not have requirements in this regard; it only requires reliable and stable operation.
Globe valves are classified as forcibly sealed valves; therefore, when the valve is closed, pressure must be applied to the valve disc to ensure that the sealing surface does not leak. When the medium enters the valve from below the valve disc, the resistance that the operating force must overcome consists of the friction between the valve stem and the packing, as well as the thrust generated by the pressure of the medium. The force required to close the valve is greater than that needed to open it; therefore, the diameter of the valve stem must be large enough, otherwise the valve stem may bend, a condition known as \"low inlet, high outlet\". In recent years, since the emergence of self-sealing valves, the flow direction of media in globe valves has changed to enter the valve chamber from above the valve disc, that is, from high to low. At this time, under the pressure of the medium, the force required to close the valve is low, while the force required to open it is high; consequently, the diameter of the valve stem can be reduced accordingly. At the same time, under the influence of the medium, this type of valve is also more airtight.
Generally, globe valves with larger nominal diameters are designed with the inlet at the higher level and the outlet at the lower level! The stop valves at the outlet of our compressors are all set to a low pressure!