Pressure Compensated Constant Flow Valves (Hydraulic Only)
  • Maintains Accurate Constant Flow at Pressures Up to 3,000 PSI (207 Bar) (Non-Shock Service)
• Adjustable and Fixed (Factory-Set) Flow Units
• Free Reverse Flow (PC5 Only

Pneu-Trol Pressure Compensated Constant Flow Valves are exceptionally accurate in maintaining constant flow with pressures up to 3,000 PSI (207 bar). Non-adjustable units (Series 3 & 4) provide exact factory-set output flow, regardless of inlet pressure, up to rated limits. Adjustable valves (Series 5) permit infinite adjustment, under pressure, of output flow independent of inlet pressures.

Series 3 is a miniature 1/4" valve for small flow rates. Series 4 is our standard fixed flow valve with flow capacity up to 30.0 GPM in the 3/4" size. Both Series 3 & 4 provide for "restricted" reverse flow as limited by the internal orifice. Series 5 provides for free and "unrestricted" reverse flow since it has an internal check valve to by-pass the internal orifice.

The compensating action of these valves results from a fixed diameter orifice or an adjustable orifice at the inlet end and a series of variable orifices at the outlet end. Flow through the variable orifices is controlled by a spring and piston. These elements work together to regulate hydraulic flow within the determined rates. Flows are controlled within ±15% up to 1.5 GPM (5.7 L/min) and ±10% at higher flow up to 30.0 GPM (113.6 L/min). Regulation is virtually unaffected by temperature changes from 60ºF (16ºC) to 180ºF (82ºC). At a temperature differential [DT] or 70ºF (21ºC) flow variation would be approximately ±2% max; while a temperature differential [DT] of 120ºF (49ºC) the flow variation would be approximately ±4% max.

Series 3 & Series 5 units are made from high-strength steel; while Series 4 units are made from aluminum for the 1/4" & 3/8" sizes and high-strength steel for 1/2" & 3/4" sizes. The standard porting of these valves is NPT with optional SAE and BSPT threads available on selected models.