II. FUNDAMENTALS OF OPERATION
E. Devices for liquid pulsation control, Suction/Inlet and discharge.
A good inlet/suction and discharge pipe layout for reciprocating pumps of conventional type frequency require no pulsation control devices to compensate for normal variations in velocity flow in the complete piping system.
Where the suction or discharge lines are of considerable length, or the inlet has sufficient head, or liquid handled is hot - a suction or discharge dampening device of suitable size may sometimes be necessary to ensure smooth, quite operation. Dampening devices should be considered as a part of the piping system, rather than as a pump accessory.
The size and pre-charge of the dampener device will depend upon the type of pump, the liquid and the layout of the piping system. Recommendations as to size and type of device(s) should be obtained from the device manufacturer. Be sure to provide full information on the piping installation. Without complete knowledge of the piping system, it is impossible to determine the size and precharge of the dampeners. For bladder type dampeners, provisions should be made to keep the unit(s) charged with nitrogen or similar inert gas, in accordance with the device manufacturers recommendations. An exhausted device is of no value.
Dampeners, particularly on the suction (which are required more frequently than discharge), should be located as-close-as-possible to the pump and in such a position that they will absorb the impact of the moving liquid column and thus cushion the pulsations in the most efficient manner.
A properly sized, located and charged device may reduce the length of pipe used in the acceleration head equation to a value of 5 to 15 nominal pipe diameters. Figure 52 in Appendix A is a suggested piping system for power pumps.
