This Control Devices VR10-013 vacuum relief valve has a brass body, an adjustable relief pressure, and a 1" male NPT threaded inlet connection. The valve's brass body, stainless steel spring, nylon poppet, and Nitrile seal resist corrosion and can be used in operating temperatures up to 250 degrees F. This proportional-type relief valve opens at a rate relative to the increase in vacuum pressure, and can be adjusted to open between 0 and 30" Hg (inches of mercury) using the knurled adjustment screw and locking jam nut. The valve is preset to open at 20 pounds per square inch (psi) and has a flow rate of 15 cubic feet per minute (CFM). This vacuum relief valve is suitable for use in vacuum applications such as to prevent a tank from collapsing while it is being emptied or after a sterilization-in-place (SIP) procedure.Relief valves remove excess pressure or vacuum from a system. The valve openings allow fluids or gases to escape to decrease pressure, and then close once the valve reaches the reseating pressure limit. They also relieve excess vacuum by opening to release a gas into the system and then closing after it reaches its low-pressure limit. Some relief valves have an adjustment mechanism to set the pressure where the valve opens, making it suitable for various applications. Relief valves are rated according to the volume of liquid or gas that can flow through them and the material that the valve is constructed from must be suitable for the fluid or gas, which may be corrosive or at an extreme temperature, in which it operates. Relief valves are used in a variety of applications, such as air compressors, petrochemical and chemical manufacturing, natural gas processing, and power generation.Control Devices manufactures valves and other flow control devices. The company, founded in 1963, is headquartered in Fenton, MO.