Vacuum Relief Valve is a protection device which is mainly mounted on a nozzle opening on the top of a fixed roof storage tank. Its main purpose is to protect the tank against rupturing as well as imploding. This valve is designed to breathe out at the time of tank filling and breathe in while the tank is being emptied. It allows the pressure in the tank to be increased above atmospheric. Such an rise in pressure enhance the boiling point of the liquid, reducing the amount of vapour which woVacuum Relief Valve,Air Pressure Vacuum Relief Valvesuld otherwise form.
Direct acting vacuum relief valves are low vacuum devices specifically designed to protect tanks, process systems and equipment from excessive vacuum. As well as providing the primary layer of protection for tanks and process systems, vacuum valves also minimize emission losses of gases or vapours, thus protecting the environment and providing significant financial savings.
Principle of Operation:- PRECON Vacuum relief valves have weight-loaded or spring-loaded pallets. Flow through the valve is controlled by the weight of the pallet or the spring force acting on the pallet to keep the device closed. Once the vacuum in the tank reaches the pallet closing force, the pallet will start to lift off the seat and allow flow through the valve.
Due to its air-cushioned sealing technology, PRECON Vacuum Relief valves prevents air intake until very close to the set vacuum. The geometry of the valves has been developed in order to optimize overall performance in terms of high flow capacity, set Vacuum, sealing and re-sealing. The modular nature of PRECON valves means they can be tailored to meet specific customers requirements: A mesh screen is fitted at Vacuum port to prevent intrusion of foreign matter into the valve.
Any special materials like ECTFE coating, PTFE coating, FRP coating, Poly Propylene, Hast alloy upon request.
Accuracy : + 5% up to 20 mbar Accuracy : + 3% above 20 mbar
Settings for Weight Loaded Design
Vacuum : 2 mbar to 40 mbar
20 mm Wc to 400 mm Wc
Settings for Spring Loaded Design
Vacuum : > 40 mbar to 900 mbar
>400 mm Wc to 9000 mm Wc