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How to properly asses the performance of a diaphragm pump

What is listed for max flow and max pressure isn't really what you should look at when assessing the performance of a diaphragm pump. Why?


Max flow is generated at zero pressure, and the max pressure is generated at zero flow. The same is true with vacuum —the max vacuum is at zero flow.

When assessing the performance of diaphragm pumps, it is crucial to comprehend the relationship between vacuum, pressure, and flow. Here's a guide to help you make accurate evaluations:

Understand Pressure-Flow Relationship

Maximum flow is observed when the pressure is zero and vice versa. This fundamental principle extends to vacuum conditions, where the maximum vacuum is achieved at zero flow.

Evaluating Pump Requirements

If your application requires a specific flow rate at a certain pressure or vacuum level, it's vital to look beyond the maximum specifications listed for the pump. For instance, a max flow rate of 30 lpm will only give you that at 0 pressure or vacuum. So, you really need a pump with a higher max flow rate that will achieve 30 lpm at the required pressure.

Interpreting Performance Curves

Pump performance curves are generated under ideal and restriction-free conditions. Any additional restrictions in your system, like orifices or tubing, will affect the actual performance. For example, introducing a two psi pressure drop will shift all the data points on the performance curve, altering the pump's expected performance in your application.

Comparing Ideal and Actual Conditions

The performance curves represent optimal scenarios. Depending on your application's specific characteristics and restrictions, actual performance may differ from the curve. Always consider these deviations when selecting a pump, ensuring it can deliver the necessary performance under your application's unique conditions.

By understanding and applying these principles, you can make more accurate and informed decisions when evaluating the performance of diaphragm pumps for your specific needs. At Dynaflo, we review all these tiny details to ensure you select the right pump for your unique application. 

We hope this helps. If you have any questions feel free to reach out


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