Factory Pump and Valve Assembly and Testing: Meeting Pump Curve Accuracy

Blog | February 14th, 2019

In hydraulics equipment, factory-branded pump and valve assemblies are put under a big microscope. Well, the instruments aren’t optical microscopes, but they do analyze the performance of these key system components in great detail. Needless to say, the graphs produced by these analytical programs look quite outlandish, at least that’s how they appear to a non-industry outsider. To the test engineers, pump curve accuracy graphs tell an important story.

Translating Pump Curve Accuracy Graphs

Obtainable in several different forms, factory pump performance is commonly recorded as experimental data then charted on a pump curve accuracy diagram. Essentially, the pump manufacturer is creating a device “fingerprint,” which can be used as a pump performance baseline. Over in our ideal world, hydraulic pumps are perfect. Unfortunately, we live in a less than ideal world, so that performance baseline is needed if the effects on the rest of the equipment circuitry are to be predicted with any amount of accuracy. On that chart, the manufacturer provides an X and Y axes. Key behavioural properties are associated with each axis. On one graph, gallons per minute and litres per second mark the X-axis. Moving vertically upward, the performance curve sharpens or flattens out as it’s influenced by pump head and impeller power.

Filled With Bench Recorded Data

Factory pumps and valve assemblies are tested under lab conditions. They’re mounted so that a manufacturers’ bench test characteristics can be plotted out and recorded. That information goes into a manual or a downloadable PDF, where it’s kept on-hand until required by an installation technician. Granted, while the data was created in a lab, it still provides useable feedback. For example, on knowing the fluid flow rate and the system head (in metres), an installer can trace the curve and see where those two visco-mechanical attributes intersect. When a uniquely shaped pump curve passes close to that intersection point, important system specs resolve. The size of an impeller becomes clear, and the horsepower rating resolves. Happily, that’s because the manufacturer has plotted out a series of translatable performance curves back at the factory.

If a factory pump or valve assembly manual goes missing, browse over to the manufacturer’s catalogue. That’s where the device should be listed. Among its specs, a graphically rendered pump curve accuracy chart will summarize its primary visco-mechanical features. To read the graph, the tech just needs a little engineering know-how. On finding the desired flow rate and head rating, as shown on the two axes, the point at which they intersect will provide invaluable pump performance information, as determined by a factory study.

Mobile Hydraulic Specialties Pty Ltd

Factory 89, 38-40 Popes Road
Keysborough, Victoria, 3173

Phone: (03) 9798-6511

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