# Radial piston pump disturbing frequency

Relatively simple question, but not one I can find an answer for. For a radial piston pump, what should I term the frequency seen on an FFT equal to all pistons having moved? This would be analogous to the vane passing frequency for a vane pump. I don't want to call it the piston rate, because that could get confused with the rate of a single piston - much like cylinder firing rate/engine firing rate for diesels.

Original Post

I thought Piston Slap referred to the mechanical impact of the piston to the side wall of the cylinder.

Walt

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WiggleRoom posted:

Relatively simple question, but not one I can find an answer for. For a radial piston pump, what should I term the frequency seen on an FFT equal to all pistons having moved? This would be analogous to the vane passing frequency for a vane pump. I don't want to call it the piston rate, because that could get confused with the rate of a single piston - much like cylinder firing rate/engine firing rate for diesels.

I use "Piston Pass Frequency".

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Sid Lane posted:
I use "Piston Pass Frequency".

What "Sid Lane" has posted, "piston pass frequency" is used for axial vane pumps.  Why should it be any different for a radial vane pump?

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Thanks for the answers so far. The only thing I would say about 'piston pass frequency' is that in axial pumps the pistons rotate, whereas they do not in a radial pump, therefore they do not pass anything, rather they are passed by a cam.

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For hydraulic pulsation, I will stick with piston pulsation frequency (PPF). It should be appropriate for any type of piston pump; whether the Pistons are connected to or driven by a crankshaft or a cam or swash plate. Why not?

Walt

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Using a throw back to an internal combustion engine, perhaps somehow introduce the term "rate".  For example the "firing rate" of a 2-stroke or 4-stroke diesel.  With the diesel of course the number differs 2-stroke vs. 4-stroke, but it is still a "rate" of occurrence of the firing rate.

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