Products
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  • 3040-400x400
  • 3040-B-400x400
Technical Specification
  
ServiceLiquids, Gases
Size2"
Connection125# FLG
Max. Inlet Pressure (psig)250
Material Specification
  
BodyCast Iron
Diaphragm ChamberCast Iron
SeatStainless Steel
DiscViton-300F max
DiaphragmViton-300F max
3040-17-F125-3-V
QTY :
Product Overview
The 3040 Series Back Pressure Valves relieve upstream pressure in a variety of processes. Automatically maintains desired maximum pressure in a vessel or system by relieving excess pressure into lower pressure return line or to atmosphere. Ideally suited for use as pump bypass control valve by maintaining constant pump discharge pressures. Used as a continuously operating valve or for intermittent protection against over-pressure conditions.
Features
• Fast response
• Viton Trim for 300°F service
• Soft “Seat” for tight shut-off
How It Works
The 3040 Series Back Pressure Valve senses upstream pressure acting on the under side of the diaphragm through a port in the bottom diaphragm case. An in crease in the up stream pressure above the set point will compress the spring and allow the valve to open. The spring will close the valve as the upstream pressure decreases to the set-point.

The higher the system pressurizes above the relief set-point pressure, the more flow the valve will pass. It is therefore typical to specify the maximum capacity of a back pressure relief valve at 10% & 20% over set-pressure.

Pressure Adjustments :
Rotating the adjustment screw clockwise increases the compression on the spring, thereby in creasing the set-pressure. Rotating the adjustment screw counter-clockwise lowers the set-pres sure. Tighten the locknut after adjustment.
Selection / Sizing / Capacities
The Relief Valve remains closed until the Set-Pressure is reached. When the Set-Pressure is met or exceeded, the spring will compress, allowing the valve to open and flow to occur. It is standard practice to publish flow values at 10% and 20% over the Set-Pressure.

Example:
A 1” valve set at 50 PSIG will pass 35.6 GPM of water or 409 SCFM of air if the system pressure exceeds the set-point by 20%.

The 3040 Series Relief Valve water and air capacities at inlet pressures of 10% and 20% over Set-Pressure:
Options
3040 Series Spring Selection Table (**Relief Pressure 1-12 PSI (Code 4) available in 1/2"-1" sizes ONLY)
Dimension and Weights