Parker R Series Relief Valves

Parker R Series Relief Valves are unique as they offer both low pressure valve line (RL4) and a higher pressure valve line (RH4). They are both designed such that when the upstream pressure exceeds the closing force exerted by the spring, the lower stem opens, permitting flow through the valve. These relief valves work from 1-25 psig crack pressure systems up to 5,000-6,000 psig crack pressure systems. The highly visible color coded labels on the valves indicate the associated crack pressure spring included in the valve.

Features/Benefits:

Pressure settings are externally adjustable while the valve is in operation. Multiple spring ranges provide greater system sensitivity and enhanced performance.

Captured molded seat design is blow-out and chip resistant.

Manual Override option with positive stem retraction is available for pressures up to 1500 psig (103 bar).

This option permits the user to relieve upstream pressure while maintaining the predetermined cracking pressure.

Color coded springs and labels indicate spring cracking range.

Lock wire feature secures a given pressure setting.

Back pressure has minimum effect on cracking pressure.

Technical Specifications:
Back-up Washer Material : PTFE
Maximum Operating Pressure (psi) : 350, 750, 1500, 2250, 3000, 4000, 5000, 6000, 25, 50, 51, 52, 53, 54, 100, 150, 225, 400
Maximum Operating Temperature (°C) : 204, 135, 107, 121, 93
Minimum Operating Temperature (°C) : -23, -57, -34, -43, -29
Maximum Operating Temperature (°F) : 400, 275, 225, 250, 200
Minimum Operating Temperature (°F) : -10, -70, -30, -45, -20
Flow Coefficient (Cv) Max : 0.41, 0.75
Connection Size : 1/4", 6 mm, 8 mm
Connection Size 2 : 1/4", 6 mm , 8 mm
Connection 1 Style : Two Ferrule Compression Fitting, Single Ferrule Compression Fitting, NPT M, NPT F, BSP F, BSP M
Connection 2 Style : Two Ferrule Compression Fitting, Single Ferrule Compression Fitting, NPT M, NPT F, BSP F, BSP M
Packing Material : Fluorocarbon Rubber, Ethylene Propylene Rubber, Nitrile Rubber, Neoprene Rubber, Highly Fluorinated Fluorocarbon Rubber
Actuation : Standard, Manual Overdrive
Cracking Pressure (psi) : 50 - 350, 350 - 750, 750 - 1500, 1500 - 2250, 2250 - 3000, 3000 - 4000, 4000 - 5000, 5000 - 6000, 10 - 25, 25 - 50, 50 - 100, 100 - 150, 150 - 225, 225 - 400
Material : 316 Stainless Steel