The pointer of the pipeline float-type flow meter goes beyond the range
Thread Content
This post was last edited by Desert Fish on 2015-10-8 at 20:36. My cold box is equipped with a nitrogen purge system; there is a float-type flow meter in the pipeline, and a pressure gauge follows. The required pressure range is 6–10 mbar. However, when I adjust the flow meter’s switch to keep the pressure within this range, the pointer of the flow meter goes beyond its scale. I’m seeking help from experts – what should I do?
It is difficult to control the flow rate with a flow needle valve. Since the cold box purge outlet is vented, the internal pressure is essentially determined by the flow rate; controlling the flow rate means controlling the pressure. Our approach is to use a flow control orifice plate to regulate the flow rate. Since it is a choked flow condition, the flow rate depends only on the upstream pressure plus the orifice area. Flow meter---needle valve---pressure gauge---throttling orifice plate. The needle valve can adjust the pressure upstream of the orifice plate, which in turn controls the flow rate. As for the pressure gauge, by seeing the pressure level, I can immediately calculate the flow rate, and then compare it with the reading from the flow meter to verify it. @jiaguoyun
Thank you, thank you. I closed a valve in the pipeline behind the pressure gauge, and now the pressure is appropriate as well as the flow rate
We welcome more people to participate in sharing and communication, to learn together and improve together