Pump Vendor Not Responsible for Pulsation Dampeners
Pumps make flow, systems cause pressure, pressure pulsation is a system response, and a system responsibility, not a pump manufacturers liability. Pumps make flow, system resistance to flow makes pressure. Flow fluctuation prevention is not pressure pulsation dampening. How bad pressure pulsation is, depends on the system pipe diameters, lengths, system liquid viscosity and specific gravity. These are all system parameters, so pulsation can not be a pump vendor responsibility. Pressure pulsation is a system phenomenon, & a system design responsibility. Think of a pump simply as one of many potential exciters of a system, like a plectrum on a string. Relief valve activity is often demonstrated as three times as bad as pump flow fluctuation. The "hunting" of flow controllers is usually far worse than pump behavior.
When dampening is made someones responsibility:
then probably, if the pump is:
A. A Multiplex "power pump" reciptocating machine, then only acceleration head will be addressed.
B. A centrifugal machine then only start up surge and its reverberations will be addresed.
C. A Vane or Gear type pump, then only high frequency resonance will be addressed.
D. A Dosing or Mertering pump or an instrument such as a mass meter, then only low frequency flow fluctuation will be addresed
When dampening is made a PIPE SYSTEM responsibility:
then probably only the potential for pipe hammer, water shock - from sudden valve closure will be addressed. It is rare for a piping people to consider the natural frequencies of the pipe.
When a PACKAGE SYSTEM system builder is involved:
because he is not told the lengths etc of the pipework to which his package is to be attached, he will want to supress pressure pulsation to a level at which it will not shake the short pipes, that is to say the high frequencies from their short length, and damage his package.
How much of flow, or on the other hand pressure, smoothing you get depends upon who you ask about the problem.
The question of pulsation, is like any other question, the answer you hear depends on how you ask the question, and on who you ask. There is only one sure way to go, ask a pulsation person direct.
Beware of any "dampener" that is "blessed" by a pump manufacturer.
1. It is unlikely to be a dampener at all.
2. It is probably, at best, a low quality accumulator that will do nothing for the system, and only protect the pump.
HOW SMOOTH DO YOU NEED YOUR SYSTEM TO BE?
