Pulsation dampers are normal applied immediately downstream of reciprocating, positive displacement (PD) pumps. Whether simplex metering pumps or large triplex machines, reciprocating PD pumps produce pulsating flows. And with each pulsation comes a resultant pressure peak. These pressure peaks may not be desirable in a given piping system, therefore the need for pulsation dampers. Generally, the application of pulsation dampers is based onone or more of the following criteria:
- To prevent potential pipe hammer / vibration
- To reduce the load on the pump itself
- To minimize or eliminate pulsations for the benefit of downstream instrumentation
- Or to minimize or eliminate pulsations as a dictate of process
In these instances, the size of the pulsation dampers relative to the displaced volume per stroke of the pump, limits pressure peaks to a pre-determined level. A gas charge pressure of nominally 80% of mean system pressure is separated from the process fluid by some sort of membrane, e.g.elastomeric bladder, diaphragm, or bellows. In actuality, these devices work much like a filter in a power supply as it converts the ripple of a rectified sine wave into dc current.