lino wrote:Perhaps worth mentioning also is that on plumbed in applications where line pressure is used, a regulator could be inexpensively installed upstream of the pump. This would allow regulatiion of pressure into the pump at some level just below the line pressure fluctuation. And that would keep pump pressure very constant.
My experience with several different industrial water pressure regulator valves is different than yours. The valves I've used (Watts, Bell and Gossett, etc) are generally far less accurate than you imply, IOW, they reduce downstream pressure variation but do NOT keep downstream pressure "constant." I'm told that there exist high-end versions of these valves that are more accurate, but I haven't tried them. What have you used? Have you really put gauges on them to watch the outlet pressure as the inlet pressure varies? I have, and the performance was surprisingly bad.
I need to try one of the high-end versions.
lino wrote:Also, I just took apart a procon pump head I had sitting here. The regulator in it is spring based, not diaphragm based. What this means is that regulated outlet pressure does not vary with inlet pressue. I have no idea why we have been hearing so long that inlet and outlet are related. Based on this pump I'm staring at, it does not appear to be true.
This from Procon's website:All relief valves are preset at the factory to your specifications (60 to 250 psi range available, 30 to 250 psi range also available on certain models, consult factory for details). At the specified relief valve setting, the flow will fully by-pass from the outlet to the inlet through the relief valve chamber. The specified relief valve setting is an average; individual pumps will vary both above and below the specified setting. The relief valve actually cracks and begins to by-pass flow at approximately 50 psi below the relief valve setting. Be advised that due to the design of the relief valve, the relief valve reacts to the difference in pressure between the inlet and the outlet. As a result, the highest pressure which the pump can develop at its discharge port is the inlet pressure plus the specified relief valve setting.