Pressure relief valves are valves used to control or limit the pressure in a system or vessel which can build up by a process upset, instrument or equipment failure, and fire. The pressure is relieved by allowing the pressurized fluid to flow from an auxiliary passage out of the system. The relief valve is designed or set to open at a predetermined set pressure to protect pressure vessels and other equipment from being subjected to pressures that exceed their design limits. When the set pressure is exceeded, the relief valve becomes the "path of least resistance" as the valve is forced open and a portion of the fluid is diverted through the auxiliary route. The diverted fluid (liquid, gas or liquid-gas mixture) is usually routed through a piping system known as a flare header or relief header to a central, elevated gas flare where it is usually burned and the resulting combustion gases are released to the atmosphere. As the fluid is diverted, the pressure inside the vessel will drop. Once it reaches the valve's reseating pressure, the valve will close. The blowdown is usually stated as a percentage of set pressure and refers to how much the pressure needs to drop before the valve reseats. The blowdown can vary from roughly 2-20%, and some valves have adjustable blowdowns.
Vernatherm Pressure Relief Options:
- Poppet Style
- Cartridge Style
- Custom (adjustable, self contained, miniature, and more..)
Poppet Pressure Relief
A poppet pressure relief valve is manufactured to be placed within a machined housing where the valve's seat is machined. The manifold contains ports and fittings mandated by your specific system while the poppet pressure relief valve regulates pressure according to your specifications.
Cartridge Pressure Relief
A cartridge pressure relief valve is special in the way that is contains the valve head and the valve seat. This valve does not require a manifold to function, typically this valve is inserted into an open ended pipe with an elbow where the valve blocks flow unless the pressure setting is exceeded. See diagram below for further clarification.
Custom Pressure Relief
Many customers need special sizes and configurations when dealing with pressure relief applications. We offer complete flexibility when working with our engineers. Some custom features include miniature sizes, low pressure settings, adjustable functions, and thermal bypass. Present an idea to our engineers and they will work together a solution tailored to your needs.