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Pressure Relief Valves

187 PRI® Pressure Relief Valve

This direct-acting valve is ideally suited for low pressure hydraulic applications where a fast-opening safety valve is needed to prevent system damage from pressure spikes. Minimum cracking pressures are available from 20-100 psid. An integral safety screen is available for added protection.

Key Product Facts
  • Safety Relief Valve
  • Diameter:0.187 inches
  • Full Open Lohm Rate:400 Lohms max.
  • Nominal System Pressure:Up to 3000 psi
  • Cracking Pressure Range:20 to 100 psi

Product Information

General Performance
Characteristic Specification
Tolerance on Cracking Pressure ± 10%
Full Open Lohm Rate Unscreened: 400 Lohms Maximum
Screened: 460 Lohms Maximum
Lohm Rate at 125% of Actual Crack Unscreened: 1100 Lohms Maximum
Screened: 1500 Lohms Maximum
Restriction at Min. Recommended Valve Lift 1500 Lohms Maximum
Reseat Leakage (90% of Actual Crack.) 10 Drops / Minute Maximum
Shutoff Leakage (85% of Actual Crack.) 10 Drops / Hour Maximum
Nominal System Pressure up to 3000 psi
Screen Hole Size (Screened Version Only) 0.008 inches Nominal
Nominal Weight Unscreened: 1.5 grams
Screened: 1.7 grams
Test Fluid MIL-PRF-83282 at 85°F
Materials
PART MATERIAL SPECIFICATION
Body 303 CRES QQ-S-763C
Pin 17-4PH CRES AMS 5643
Spring 17-7PH CRES AMS 5678
Ball 440C CRES AMS 5630
Cage 303 CRES QQ-S-763C
Spring Seat 303 CRES QQ-S-763C
Ball Follower 303 CRES QQ-S-763C
Screen (Screened Version Only) 304L CRES ASTM A 666
Braze (Screened Version Only) - AMS 4774
Finish: All CRES parts passivated.
Pins are prewaxed. Do not degrease. Do not lubricate.
Flow Curve
Cross Section Views
Dimensional Views
Installation Hole Details

Part Numbers & Specifications

This table below contains the part numbers and technical specifications for this product. If you have specific questions, need a quote, or would like to request a handbook or drawing, click the red request button in the column on the far right.

Image Specifications
Flow Curve
Part Numbers & Specifications
Filter Part Numbers
Flow Direction
SCREEN
PART NUMBER
Flow Direction
SCREEN
Cracking Pressure (psid) Request Information
PRFA1872020L Forward Unscreened 20 Request
PRFA1872040L Forward Unscreened 40 Request
PRFA1872060L Forward Unscreened 60 Request
PRFA1872080L Forward Unscreened 80 Request
PRFA1872100L Forward Unscreened 100 Request
PRRA1872020L Reverse Unscreened 20 Request
PRRA1872040L Reverse Unscreened 40 Request
PRRA1872060L Reverse Unscreened 60 Request
PRRA1872080L Reverse Unscreened 80 Request
PRRA1872100L Reverse Unscreened 100 Request
PRFA1875020L Forward Screened 20 Request
PRFA1875040L Forward Screened 40 Request
PRFA1875060L Forward Screened 60 Request
PRFA1875080L Forward Screened 80 Request
PRFA1875100L Forward Screened 100 Request
PRRA1875020L Reverse Screened 20 Request
PRRA1875040L Reverse Screened 40 Request
PRRA1875060L Reverse Screened 60 Request
PRRA1875080L Reverse Screened 80 Request
PRRA1875100L Reverse Screened 100 Request
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Installation & Accessories

Replacement Parts & Accessories
PART NUMBER DESCRIPTION
CUTA1870104C Installation / Extraction Tool Set
JETA1870004A Replacement Pin
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From plugs to solenoid valves, there’s a vast array of products that The Lee Company can offer. If you’d like to discuss the best solution for your specific application or to learn more about our capabilities, use-cases, or quality standards, contact your local Lee sales engineer.