How to determine the pressure difference between the front and back of the regulating valve on the negative pressure pipeline
Thread Content
How to determine the pressure before and after the regulating valve and the pressure difference on the negative pressure pipeline? The process is only small, but the kv value calculated by the calculation software is very large due to the small pressure difference, making it impossible to select a valve. This post was last edited by saaaa on 2008-3-2 11:34 ]
When the process only says very small, does it mean that the flow rate is very small or the pressure is very small? The pressure and pressure difference before and after the regulating valve on the negative pressure pipeline should be calculated according to the conditions given by the process. Provide the process conditions (medium, flow range, density, temperature, etc.) to the regulating valve manufacturer. They can calculate the CV value and select the valve.
The negative pressure pipeline should be gas. Most of the time it is the flue system of a boiler or industrial furnace, with an exhaust fan in front. In this case, various dampers are generally supplied in complete sets. The pipes are large and the adjustment accuracy requirements are not particularly high.
The tower and tank are in a vacuum state. Liquid flows in the pipeline. It refers to the small pressure difference. If the cv value calculated by taking 0.001mpa is too large, the valve diameter exceeds the pipeline diameter.
You can take a certain percentage of the pressure difference between the equipment before and after the regulating valve as the pressure difference for calculating the regulating valve.