Pressure Limiting Drivers (PLD)
Clarke's Pressure Limiting Driver (PLD-DS) technologies protects both the suction supply piping and discharge connections from over and under pressurized conditions during operation, increasing reliability of the fire pump sprinkler system.
The Clarke PLD for discharge pressure limiting control (-D) is a UL/FM certified diesel engine fire pump driver that reduces engine speed to limit maximum pump discharge pressure. Since pressure is squared by rpm, by lowering the speed, output water pressure is reduced to maintain a constant system pressure.
As shown in the table, when engaged, the PLD system reduces the pump speed to maintain a constant maximum sprinkler system pressure.
Huge Sprinkler system and standpipe cost savings can be obtained while increasing the reliability of the system by:
- Reducing the quantity of pressure control valves on high rise applications by limiting the maximum pressure applied to the sprinkler system
- Eliminating the need for break tanks, saving cost and space
- Enabling one to use a pump with a steeper rise to shut off pressure curve, which typically requires less horsepower, which can reduce the total cost of the fire protection system.