Pulsation Dampeners and Reciprocating Pumps

On seawater RO plants the practice is to install what is basically a short length of fire hose on the inlet side of the pump, and call it an "acceleration tube". Job done.

the rule of thumb is as close as possible to the pump for the suction and discharge side.normally charge gas to be avoided as it needs another source and monitoring pressure etc.Hope you have arrived the volume bottle sizing after providing the piping isometrics( suction + discharge)to the vendor.

First step is to get the pump vendor to recommend dampener sizes based on your system and actual pump. However, very basically and and with reference to the Pump Handbook - Karassik et al (McGraw Hill; (a book you should purchase if you have anything to do with pumps)

"An effective suction dampener is a vertical air chamber made from pipe with a connection at the top for recharging. The ID of the chamber should be as close as possible to the ID of the pipe. The height of the chamber approximately 8 to 10 pipe diameter with a minimum of about 600 mm with an air cushion of about 300 mm.

Dampeners on the discharge are usually nitrogen filled bladder bottles.Pressure in the bladder about 66% of discharge system pressure."