The Elmac Technologies® range of direct acting Pressure/Vacuum Relief Valves are low pressure devices specifically designed to protect tanks, process systems and equipment from excessive pressure and vacuum.
Elmac’s low pressure equipment is designed to protect tanks from rupture or implosion during filling and/or emptying cycles. They limit product loss and environmental discharges whilst also protecting tanks during thermal changes. Adequate pressure protection is required to stop the catastrophic failure of a tank or vessel.
The need for pressure protection
Adequate pressure protection is required to stop the catastrophic failure of a tank or vessel.
A tank can be fitted with:
– a high level alarm, but this might be turned off due to faulty readings
– a pressure control system, which could be out of service
– a pressure relief valve with a flame arrester, which may be isolated after maintenance
Without any means to vent the build-up of internal pressure, when a product is transferred into the tank, it can easily become over-pressured until the roof ruptures, throwing it to the ground. And all despite only reaching a few psi over atmospheric pressure
Pressure protection – normal venting requirements
Changes in the liquid volume are caused by routine filling and emptying of a storage tank that inherently increase and decrease the vapour space.
Changes in the temperature of the vapours and liquids in the tank are the result of variations in the ambient atmospheric temperatures. These fluctuations in temperature and volume also cause fluctuations in pressure.
Normal venting relief will allow the tank to breathe, preventing collapse or overpressure of the tank.
Our pressure & vacuum relief valves are specifically designed to protect tanks from under or over pressurisation when correctly sized. They protect against the fluctuations in pressure associated with the general operation of a storage tank:
• Thermal Expansion
Pressure protection – emergency venting requirements
The temperature of the stored liquid and vapours may also increase as a result of the tank being exposed to an external fire.
Large volume of vapours will be generated as a result of this heat input, providing a means of discharging this large volume of vapours and prohibiting an increase of pressure within the tank is defined as emergency venting.
Emergency venting is a form of pressure protection that helps to protect the tank from catastrophic damage caused by an explosion which in turn protects the immediate vicinity of the tank where there may be people or other tanks.
Elmac offers a full range of pressure protection equipment. For more detailed information, please select a specific product from our range below.