I would like to ask an expert about the safety valve of the backpressure valve in metering pumps.
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Details: A new setup has been installed in the factory – a regular diaphragm metering pump (50 L/h) is connected in parallel with a backpressure valve/safety valve (18615), and the flow then goes directly to the flow meter and onward to the downstream equipment. There are no devices such as pulsation dampers. Question: 1. Is this installation correct, and what is its purpose? 2. When the unit arrives, the inlet of the back pressure valve is on the upper side (as indicated by the arrow on the back pressure valve); could it be installed in the wrong direction? 3. Is it installed in this position to act as a backpressure valve or a safety valve? 4. During testing, it was found that the flow rate was unstable with significant fluctuations. Is there any way to solve this?
The attached image captured the cursor inside; I took a new screenshot.
Shouldn’t the Y-filter be at the front of the metering pump? Is a safety valve a one-way valve? Shouldn’t it be connected in series with a metering pump?
It was made by the device manufacturer, so I’ve always suspected there was a problem.
Why is the Y-filter installed after the pump? I don’t understand. Impurities in the material can sometimes affect the proper operation of the metering pump. Diaphragm metering pumps are equipped with check valves, and the accumulation of impurities in these valves can cause unstable flow rates. It is also necessary to consider whether the material is suitable for use with diaphragm metering pumps.
In the entire process diagram, no metering pump manufacturer would likely install a filter at the outlet; moreover, the 18615 serves as a safety valve
A backpressure valve should be installed at the pump outlet to create backpressure and stabilize flow. A Y-type filter should be placed before the pump inlet, at the outlet of the storage tank. Since metering pumps experience significant vibration, it is recommended to install dampers to reduce this vibration.
Generally, the filter is installed on the inlet side of the pump, while the outlet safety valve serves as a diaphragm for overpressure protection.