Phenomena occurring when metering pumps are used in parallel

We all use it individually, with the setting set at 50

We use them individually as well, but I think it’s completely feasible to use them in parallel from a theoretical perspective, because the two pump heads of each pump are actually connected in parallel; in other words, two pumps are equivalent to having 4 pump heads

Several issues need to be confirmed: First, whether the pump’s inlet is blocked or if there is a vacuum at the inlet. Second, whether the outlet of the pump has been expanded after being connected in parallel; in other words, whether there is any liquid blockage. Third, whether the solvent is corrosive to the pump, causing leaks in the gaskets

I encountered the same problem; I was eager to test the system, and in my haste, I removed it without resolving the issue, then replaced it with a gear pump along with a flow meter and valve control.

Metering pumps can be used in parallel, and the reasons for this phenomenon are roughly as follows: 1. If the diameters of the inlet and outlet pipes are not appropriate, proper supply at the inlet cannot be ensured; this results in normal operation at first when the pumps are connected in parallel, but over time, as the supply becomes insufficient, flow instability occurs. 2. The check valve of the metering pump is leaking. 3. The properties of the material also play a role. In most cases, it is caused by the valve not closing properly.

The most likely possibility is that the check valve has an internal leak.

It’s completely possible. Some manufacturing processes require multiple additives, which are fed together in proportion into a single pipeline. First of all, I think it’s important to consider whether the outlet pipeline is properly designed, and whether the pressure losses in the inlet pipelines of the two pumps are roughly equal; also, it’s necessary to check whether there is any internal leakage in the metering pumps themselves

Hello, my friends! First of all: thank you to all my friends for their help! 1) As for the first possibility of a sudden drop in incoming traffic, I am not able to give a definite answer at the moment. Because this flow at the inlet is a branch of the pump outlet (the pump outlet has five branches, two of which are in use); I can check this by looking at the historical data! 2) Regarding the leakage of the outlet check valve, I don’t think it’s very likely to be the cause, as during the subsequent adjustments the flow rate fluctuated greatly; in fact, when I increased the pump stroke, the total outlet flow rate decreased instead. And later, during operation with a single pump, the flow rate was very stable! (The flow curve is a sine-cosine curve; it corresponds to a single pump head.) 3) The fluid being transported is hot water (103 degrees). I don’t think it will have a big impact on the pump! Please ask friends to keep helping out

——““The fluid being transported is hot water (103 degrees)” – it’s possible that the temperature of the pump rises over time due to prolonged operation, and the vaporization of the hot water causes fluctuations in flow rate!

What was said upstairs is quite comprehensive. I would like to add that diaphragm pumps operate by the intermittent compression of a diaphragm; so, can two such pumps maintain consistency in their compression frequency while they are in operation? If not, then does the medium being pumped intermittently by the two pumps when connected in parallel experience mutual impact? If this continues, the pressure of the fluid coming out of your pipeline will not remain stable.