[67] PRV, internally controlled, cushioned
Pressure relief valves
often incorporate cushioning pistons or flow control valves. The
cushioning device shown provides fast opening and slow closing of
the valve. This prevents damage caused by pressure shocks (smooth
valve operation).
Pressure shock arise, for example, when the pump delivers oil in an almost unpressurized condition and the supply port of the load device is abruptly closed by a directional control valve.