These two-stage spool valves maintain a reduced outlet pressure against variations in inlet pressure, and are able to act as relief valves (at 50% of maximum flow) to prevent excess pressure being developed when an actuator is subject to a reactive load. Relief flow is directed to the TB port. Therefore, for the relief function to operate, all components above this DGMX2 module must contain the TB port, and the directional valve must have the TB bypass feature.
Pilot control may be from the P, A, or B port. Pilot drain flow may be directed internally to tank port TA, or externally out of the valve body.
Any pressure in the line to which these valves are drained is additive to the valve pressure setting.
The valve pressure setting is adjustable by means of either an adjusting screw containing an internal hex, a hand-adjust knob, or a micrometer knob with keylock.
Different spring ratings cover an overall pressure range from 2 to 315 bar (30-4500 psi).
The metering spool element in this design is always positioned in the P line. The connection of the pilot control line determines at which port the reduced pressure is obtained. For example:
The A and B line models provide for reduced pressure when P is connected to A or B. It allows free flow through the service port when connected to T (all via a four-way directional valve).
Basic Characteristics
Maximum flow: 120 l/min (32 USgpm)
Pilot flow@ 50°C (120°F) and 315 bar (4500 psi): 290–420 ml/min (18 in3 /min-26 in3 /min)
Maximum operating pressure: A models - 70 bar (1000 psi) (inlet pressure) 50 bar (725 psi) (reduced pressure): B, F and G models - 315 bar (4500 psi)
Leakage flow rate @ 50° C (120° F) and 315 bar (4500 psi): 80-200 ml/min (15-12 in3/min) (Leakage to TB around spool land @315 bar (4500 psi)
Operating temperature: -0° to 80°C (32° to 180°F)
Weights: 3.5 kg (7.7 lbs)