Seeking advice on metering pump issues
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I recently bought a metering pump for testing purposes. After connecting the pipes, I installed a turbine flow meter on the outlet pipe, but the flow rate measured was quite variable – the flow rate at 80% of the scale fluctuated between 0.3 and 0.4. I was wondering if this is normal. A damper was also installed; does that mean it’s not possible to use a flow meter for measurement?
Metering pumps are positive displacement pumps that inherently exhibit some pulsation; to reduce this pulsation, an outlet buffer tank with a large capacity can be used, and it is advisable that the volume of such a tank be more than 15 times the flow rate per stroke.
There are many types of metering pumps; I’m not sure whether your metering pump is diaphragm-type or mechanical-type Plunger? Hydraulic?
The metering pump itself can perform metering; if a flow meter is needed, it must be added at a location far away from the pump body.
As long as the stroke length of a metering pump remains constant, the volume delivered with each stroke is essentially fixed. For smaller metering pumps, we usually use a measuring tank at the inlet in order to calibrate the flow rate, by measuring the volume delivered over a certain period of time!
My pump has a flow rate of 360 L/H, and the damper capacity is 0.6 L. Is such fluctuation in flow rate normal?
Due to the low flow rate of your pump, there are many factors that can cause fluctuations, and coupled with the high sensitivity of the flow meter, a buffer tank with a capacity of 1.5L to 2L can help reduce these fluctuations to some extent, though they cannot be completely eliminated.
Is a fluctuation of 0.3~0.4L still significant? Is that okay?