The CavGuard is the age old suction side "Stand Pipe" with a couple of differences. It is forced to replenish its bubble cap, but the bubbles, before they are reabsorbed, are forced to rise away from the pump suction intake. Like steam injection dampers. The orifice is chose to remove excess force from suction lines that are supplied by centrifugal pumps at a high pressure.
The suction line is destabilizing suction check valves of positive displacement reciprocating pumps. Too much pressure force combines with a large driving mass from a long supply line is the worst enemy of efficient pumping, because it drives the suction side which the pump has been designed to be in control of filling itself.
Selecting a cavitaiton or suction hammer preventer may require suction system analysis.
Hardware prices do not absorb analysis, please contact Liquid-Dynamics.com.