One of our members writes:
“I work for an aircraft ground servicing manufacturer and we test hydraulic flow for various restrictor check valve assemblies. We have a test bench that maxes out at 2500 psi and 20GPM, using a 30HP electric motor. We need to test a new restrictor that requires 3500psi and 26GPM. I was wondering if we could somehow leverage our existing equipment (with some modifications) to be able to do so, without having to purchase a new 60+ HP electric motor and a larger pump?”
This is a common dilemma for repair shops and other hydraulic test bench owners: unless you build a REALLY BIG test bench at the outset, sooner or later you’re going to get a component you don’t have the capacity (flow and/or pressure) to test. It’s Murphy’s Law.
To the question above, assuming the existing pump is capable of the required 3500 psi working pressure, then available flow from the existing pump, which is determined by the power of the electric motor, is given by:
Flow (GPM) = (HP x 1714)/ pressure (psi) = (30 x 1714)/3500 = 15 GPM
With 26 GPM required, the additional 11 GPM could be supplied by an accumulator. And if the existing pump is not capable of working at the required pressure of 3500 psi, an intensifier could be installed to enable the accumulator to be charged to a pressure sufficient to ensure 3500 psi (and the required flow) is available to test the restrictor.
The unfortunate reality in these situations is you can increase available pressure by reducing flow (pressure intensification), or you can increase available flow by reducing pressure (flow intensification), but you can’t do both at the same time It means if neither of the above work arounds get you over the line, the only alternative is to install more input power, with a corresponding increase in flow and pressure. This means building a modest test bench in the first place can turn out to be a mistake. And to discover six other costly mistakes you want to be sure to avoid with your hydraulic equipment, get “Six Costly Mistakes Most Hydraulics Users Make… And How You Can Avoid Them!” available for FREE download here.