U.S. Patent 7,069,945
A screw-in, cartridge-style, pilot-operated, two-stage, hydraulic relief valve with reverse flow check valve. It is intended for use as a pressure limiting device in demanding hydraulic circuits which require fast response, low hysteresis, low leakage, low pressure overshoot and reverse free flow features.
The RV50-28 blocks flow from 1 to 2 until sufficient pressure is present at 1 to force the pilot stage open, allowing the main stage to shift, opening 1 to 2.
The relief flow path is from 1 to 2. Reverse flow, from 2 to 1, occurs when the pressure at port 2 is at least 2.1 bar (30 psi) higher than at port 1.
• Adjustments cannot be backed out of the valve.
• Hardened spool and cage for long life.
• Fast response.
• Industry-common cavity.
Operating Pressure: 344 bar (5000 psi)
Proof Pressure: 621 bar (9000 psi)
Burst Pressure: 241 bar (8000 psi)
Flow: 113.6 lpm (30 gpm)
Adjustable Pressure Range: 17 bar (250 psi) to 345 bar (5000 psi)
Internal Leakage: 0.5 ml per minute (10 drops/minute) max. to 80% of nominal setting
Crack Pressure Defined: bar (psi) evident at 7.6 lpm (2.0 gpm) attained
Reseat Pressure: Nominal 90% of crack pressure
Crack Pressure: 2.1 bar (30 psi)
Approx Pressure Increment per Adjuster Turn: 99 bar (430 psi)/turn
Response Time: Relief to Check Valve at 24 bar/53 lpm (3500 psi/14 gpm) condition; 0.6 sec.
Response Time: Check to Relief Valve at 24 bar/53 lpm (3500 psi/14 gpm) condition; 0.3 sec.
Temperature: -40° to 100°C (-40° to 212°F) with Buna seals;
-26° to 204°C (-15° to 400°F) with Fluorocarbon seals
-54° to 107°C (-65° to 225°F) with Polyurethane seals
Filtration: See page 9.010.1
Fluids: Mineral-based or synthetics with lubricating properties at viscosities of
7.4 to 420 cSt (50 to 2000 sus); See Temperature and Oil Viscosity, page 9.060.1
Installation: No restrictions; See page 9.020.1
Cavity: VC10-2; See page 9.110_2w
Cavity Tool: CT10-2xx; See page 8.600.1
Seal Kit: SK10-2x-B; See page 8.650.1