Pneu-Trol pressure compensated constant flow valves are exceptionally accurate in maintaining constant flow with pressures up to 3,000 psi (207 bar). These non-adjustable units provide exact factory-set output flow, regardless of inlet pressure, up to rated limits.
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 (113.6 lpm). Both Series 3 & 4 provide for "restricted" reverse flow as limited by the internal orifice.
The compensating action of these valves results from a fixed diameter 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 lpm) and ±10% at higher flow up to 30.0 gpm (113.6 lpm). Regulation is virtually unaffected by temperature changes from 60° F (16° C) to 180° F (82° C). At a temperature differential [ΔT] of 70° F (21° C) flow variation would be approximately ±2% max; while at temperature differential [ΔT] of 120° F (49° C) the flow variation would be approximately ±4% max.
Series 3 units are made from high-strength steel. 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 NPTF with optional SAE threads available on selected models.