Brownell Limited has developed Deluge Valve, the latest extended range of ultra high flow performance pressure relief valves suitable for low pressure differentials. The valve covers a range of pressure setting that goes from 0.5 to 5 psi and it is available in three standard sizes 1’’, 3’’ and 8’’.
Pressure relief valves represent the last chance to prevent a disaster; therefore they must be reliable and functioning constantly and in every condition. The Deluge Valve can operate in aggressive environments at low and high temperature and in conditions of driving rain. In addition, the material, of which the valve is made, must be compatible with the fluid contained in the storage vessel in order to prevent chemical reactions between the valve and its content. Deluge valves can withstand corrosive chemicals and can be manufactured in different materials, such as aluminium alloy, brass and stainless steel, in accordance with the specific requirements of the customer.
The Deluge Valve uses a simple but innovative design concept. Pressure valves often employ springs as loading devices. However, a variation on the layout of the springs within a deluge valve allowed a considerable decrease in superimposed backpressure immediately after the valve opens. This entails an overall decrease in pressure differential and an increase in air flow compared to equivalent conventional valves.
The following graph shows the results of a test conducted on a valve which had the crack point at 0.4 psid, corresponding to the design-lift pressure.
The unusual operating characteristic of the Deluge Valve can be seen from the trend of the graph. The Deluge Valve does not open to the maximum extent until the pressure exceeds the pressure at the toggle point (maximum opening operating conditions). When the toggle point is reached, the Deluge Valve is fully open. At this stage, the pressure differential in the Deluge Valve starts reducing to a value close to the crack pressure. After the pressure differential reached this minimum value, this quantity began increasing again. Beyond the toggle pressure, the Deluge Valve is able to offer a considerably lower pressure differential combined with high venting performance. The Deluge Valve is designed for those situations in which, the safety requirements impose tight constraints on the maximum allowable pressure which in the majority of the applications has been identified as the parameter that has to be monitored.
