[22] Circuit symbol for pressure valves
Pressure valves are
represented using squares. The flow direction is indicated by an
arrow. The valve ports can be designated as P (supply port) and T
(tank return port) or as A and B. The position of the arrow
within the square indicates whether the valve is normally open or
normally closed. Adjustable pressure valves are indicated by a
diagonal arrow through the spring. Pressure valves are divided
into pressure relief valves and pressure regulators.