• Reduced trim for low-flow applications, all sizes.
• Locking cap to enclose adjusting screw (1).
• Wetted materials (7,8 & 10) in type 316SS, Monel, titanium, and Hastelloy.
• Upgrade non-wetted spring chamber (2), spring hardware (3,5), and adjusting screw (1) to 300 series stainless steel.
• Hard-chromed piston (7) for longer life and seal (9) wear.
• 1/4" NPT inlet and outlet pressure gauge connection. Generally not recommended if accuracy is required due to turbulent location in flow stream.   
• Custom seal materials for special applications where PTFE seals (9) may not be suitable.

• Pressure-containing parts made from solid bar stock materials — unlike castings which have wall thickness variations.
• Body and trim: Standard material is type 303 or 316 stainless steel. Special alloys (e.g. Hastelloy, Monel, titanium, and Alloy 20) also available.
• Teflon PTFE V packing seals: High-pressure, low-friction, self-expanding design permits operation with small differences between inlet and outlet pressures as low as 50-75 PSI (approx), as long as the packing nut is not overtightened and piston surfaces are kept clean.
• Spring chamber and adjusting spring: These parts are non-wetted, are not in contact with the fluid or gas, and are normally offered in carbon steel, painted for minimal exterior corrosion-resistant protection. When these parts are submerged or located in a corrosive atmosphere, they can be upgraded to a stainless steel or other corrosion-resistant materials at an additional cost. The spring chamber is not offered in aluminum or plastic.
• Standard porting: Right-angle porting, NPT threads (side inlet, bottom outlet). Valve works in any orientation, upright as illustrated, horizontal, etc. See also threaded model PRH-04-FLG.
• Optional porting: Side outlet (parallel port), or in-line porting can be supplied at additional cost when requested.
• Other options: Reduced trim for low-flow applications, locking cap, inlet or outlet pressure gauge ports,

This valve operates with a compression spring acting on the main valve which is used to adjust the outlet pressure with an adjusting screw. The reduced outlet pressure is very easily adjusted in the field. To increase outlet pressure, simply loosen adjusting screw lock nut (2) to increase spring compression by turning the adjusting screw (1) inward. Similarly, to get a lowering in outlet pressure requires a reduction in spring compression by turning the screw outward. A pressure gauge is required on the outlet side of the regulator somewhere in the downstream piping close to the valve, to monitor the result while making the adjustment. An optional 1/4" Npt pressure gauge connection is added, only when ordered. The valve will operate in a vertical orientation as illustrated, horizontal, or any other orientation.