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Keckley Back Pressure Relief Valves

Keckley
Back Pressure Relief Valves

Single Seat - Tight Closing Stainless Steel Ball and Seat Set Pressures 10 to 75 psi Steam, Air, Water, Oil Service

Service: Type 405 Ball Type Back Pressure or Relief Valves are ideal for use on low or medium pressures because of their large capacity, close regulation, and tight closing features. They are adapted to steam, water, air or similar fluids at pressures between 10 and 75 psi and are made in sizes up to 2112 inches, inclusive.

Construction: The improved and rugged construction of these valves, combined with careful workmanship and best materials, insure years of trouble-free service. The bodies are heavy steam bronze in sizes below 2 inches. The 2 inch and 21/2 inch sizes have cast iron bodies. All sizes have stainless steel seats and stainless steel balls. The springs are steel, cadmium plated. The bracket screws into the body in sizes below 2 inches and is bolted to the body in the larger sizes. This is stronger and more rigid than the usual construction where the bracket is mounted on the stuffing box.

Operation of Type 405: Inlet pressure holds the ball on the seat and the valve remains closed until the inlet pressure, transmitted through the feeler pipe, is high enough to move the diaphragm and stem against the spring force and push the ball of the seat. The valve will operate in any position.

Pressure Range: Long springs are used for better regulation. They are compressed to working length when installed in the bracket. Consequently the spring tension cannot be released for reduced pressures much lower than the maximum for which it is designed. Several interchangeable springs are used to cover the 10 to 75 psi range. Each has an adjustment range of about 10% above or below its rated pressure. If a wider range of adjustment is specified, a shorter spring must be used at a sacrifice of regulating accuracy.