1AR Series Relief Valve Overview
This document provides technical specifications and operational details for the 1AR Series Relief Valve, a pilot-operated valve designed for pressure control in hydraulic systems. It is suitable for continuous duty and accurate pressure control with both constant and varying flows.

Specifications

• Rated Flow: 60 litres/min (16 US GPM)
• Max Setting: 350 bar (5000 psi)
• Body Material: Standard aluminium (up to 210 bar), steel option available
• Weight: 1AR60 - 0.18 kg (0.4 lbs), 1AR65 - 0.36 kg (0.8 lbs), 1AR66 - 0.48 kg (1.0 lbs)
• Seal Kit Number: SK613 (Nitrile), SK613V (Viton)
• Recommended Filtration Level: BS5540/4 Class 18/13 (25 micron nominal)
• Operation Temperature: -20°C to +90°C
• Nominal Viscosity Range: 5 to 500 cSt
• Leakage: 35 millilitres/min nominal

Features

• High accuracy due to pilot-operated design
• Hardened working parts for long, reliable life
• Cartridge construction for easy installation

Operation
When the inlet pressure exceeds the valve setting, the pilot section opens, causing a small flow across the orifice in the main spool. This pressure drop moves the spool against a light spring, opening radial holes in the sleeve and allowing relief flow to the tank.

Ordering Information

• Basic Codes: 1AR60 (Cartridge Only), 1AR65 (Cartridge and Body), 1AR66 (Cartridge and Body Through ported)
• Adjustment Means: P (Leakproof Screw Adjustment), R (Handknob Adjustment), G (Tamperproof Cap)
• Port Sizes: 3/8’’ BSP, 1/2’’ BSP, 3/8’’ SAE, 1/2’’ SAE
• Seals: Nitrile for most hydraulic oils, Viton for high temperature and special fluids
• Pressure Range: 10-100 bar, 10-210 bar, 50-350 bar

Contact Information
Integrated Hydraulics Ltd, UK and Integrated Hydraulics Inc, USA. For further details, visit www.integratedhydraulics.com.