How to Calculate Temperature Drop Across Gas Valve

Temperature changes when valves constrict flow.

The pressure acting on a gas valve, combined with the gas's rate of flow, produces an energy differential across it. When no mechanical work occurs at the valve, this energy change manifests as a change in temperature. A high temperature drop can reduce a system's efficiency. Methods for reducing the temperature change across a valve include installing additional, separate pressure release valves and adding area from which heat can dissipate.

Instructions

1. Multiply the volumetric flow rate past the valve by the pressure acting upon it. If, for instance 0.02 gallons flow per minute at 300 pounds per square inch of pressure: 0.2 x 300 = 6.

2. Divide your result by 1,714, which is a set conversion value: 6 / 1,714 = 0.0035. This represents the rate of energy change across the valve, measured in horsepower.

3. Multiply your answer by 1,000, another set conversion value: 0.0035 x 1,000 = 3.5.

4. Divide the result by the surface area of the valve. If the valve offers a surface area of 2.3 square feet: 3.5 / 2.3 = 1.52 degrees Fahrenheit. This answer is the temperature drop across the valve.

References

• North Dakota State University: Thermal Properties
• Womack Systems: Cooling in Hydraulic System

Resources

• Sawyer Systems: Formulas
• Ram Industries: Fluid Power Formulas
• Rousseau Controls: Formula