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94640 Pilot Operated Relief Valve (Diaphragm Pilot)

Brand: Shand & Jurs
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The Shand & Jurs 94640 Pilot Operated Relief Valve is designed to meet very specific pressure needs. 

The high accuracy of the valve allows the pressure to be set between 0.11 psig to 15.0 psig using sensitive springs for discrete ranges. 

The valve operates as follows:

As the internal tank pressure reaches the valves set point, the upward force on the sensing and boost diaphragms overcome the downward spring force causing the pilot to fully open. 

This causes a large pressure reduction on the upper side of the main valve diaphragm which results in a full lift of the main valve seat.

When the pressure reduces to the point its resulting upward force is less than the spring force, the pilot seat begins to close. This, in turn, builds up pressure on the upper side of the main valve diaphragm which closes the main valve seat. 

The pressures are again returned to their normal operating levels.

The valve’s set point and blowdown can both be adjusted externally with blowdown adjustment range from 5-20%. The valve operates in a snap action mode only, and provides full opening at set point.
Features
  • Set pressure between 0.11 psig to 15.0 psig
  • Valve sizes: 2″ x 3″, 3″ x 4″, 4″ x 6″, 6″ x 8″, 8″ x 10″, 10″ x 12″, and 12″ x 16″
  • Adjustment of the valve can be made externally
  • Bubble tight seat to set pressure
  • Snap action
  • Fully open at set pressure
  • Minimize VOC’s and odor emissions
  • Accessories: Backflow/Vacuum Preventer, Field Test Connection, Sense Line Filter (Single or Dual), Pilot Vent Pipped to Flange Outlet, Remote Sense Line
The Shand & Jurs 94640 Pilot Operated Relief Valve is designed to meet very specific pressure needs. 

The high accuracy of the valve allows the pressure to be set between 0.11 psig to 15.0 psig using sensitive springs for discrete ranges. 

The valve operates as follows:

As the internal tank pressure reaches the valves set point, the upward force on the sensing and boost diaphragms overcome the downward spring force causing the pilot to fully open. 

This causes a large pressure reduction on the upper side of the main valve diaphragm which results in a full lift of the main valve seat.

When the pressure reduces to the point its resulting upward force is less than the spring force, the pilot seat begins to close. This, in turn, builds up pressure on the upper side of the main valve diaphragm which closes the main valve seat. 

The pressures are again returned to their normal operating levels.

The valve’s set point and blowdown can both be adjusted externally with blowdown adjustment range from 5-20%. The valve operates in a snap action mode only, and provides full opening at set point.
Features
  • Set pressure between 0.11 psig to 15.0 psig
  • Valve sizes: 2″ x 3″, 3″ x 4″, 4″ x 6″, 6″ x 8″, 8″ x 10″, 10″ x 12″, and 12″ x 16″
  • Adjustment of the valve can be made externally
  • Bubble tight seat to set pressure
  • Snap action
  • Fully open at set pressure
  • Minimize VOC’s and odor emissions
  • Accessories: Backflow/Vacuum Preventer, Field Test Connection, Sense Line Filter (Single or Dual), Pilot Vent Pipped to Flange Outlet, Remote Sense Line
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Specifications

Brand

Pressure Setting

  • 0.11 psig to 15 psig available in discrete ranges

Standard Blowdown

  • 5 % - 20 % (Adjustable)

Body Construction

  • Aluminum, Steel, or Stainless Stee

Diaphragm

  • FEP (Fluorinated Ethylene Propylene), FKM (Fluoroelastomer), NBR (Nitrile-Butadiene)

Accessories

  • Backflow/Vacuum Preventer, Field Test Connection, Sense Line Filter (Single or Dual), Pilot Vent Pipped to Flange Outlet, Remote Sense Line

Flange Connection

  • 150 lb ANSI
  • Other Flange Types Available

Vacuum

  • See Model 94645
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Applications

  • Meeting Emissions Standards for Process and Storage Tanks Requiring Pressure Relief
  • Hot Hydrocarbon Vapors or Liquids, Corrosive Liquids, Gas, Cryogenics
  • Tanker Ships, Vessels, Petroleum, Chemical, Oil, Gas, Marine, Environmental Plants, Sanitary and Cryogenic Industries. Tank Applications Operating very Close to Set Pressure
  • Low Pressure Safety-Relief Valve for Vessel Applications, from General Product Tank Storage to Transportation Vessels
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