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THE PLD AOSTeP LEAK'OTES T I The Red Jacket PLD leak detector is duct escapes from the system as is the PLD to open to the full-flow posi- a pressure-sensing, piston-operated metered in through the PLD. Under tion. In a system with no leaks, it valve designed to indicate a leak in this condition pressure cannot build takes approximately two seconds for the piping between the leak detector up in the piping system. When a noz- a complete test. No further line and the dispenser. zle is opened, a poppet in the PLD testing takes place until the line When the submerged pump is turn- moves to a position that restricts the pressure drops below 1 psi. ed on, a controlled amount of product flow to approximately 11/7 to 3 GPM. (three gallons per hour) is metered This is the indication to the operator NOTE: For PLD to operate properly, through the PLD into the piping sys- that a leak is present. submersible pumping unit must be tem. If a leak is present that equals If there are no leaks, pressure able to produce a minimum of 22 psi. or exceeds this amount, as much pro- rapidly builds in the system forcing I \\ J Position 1 Position 2 j Position 3 . ,t Vented Vented vented to Tank to Tank I to Tank Pressure Relief Valve 20.22 PSI i Lessthan 1 PSI i moi' � I Full Pressure Full Pressure \ r Full Pressure Poppet Approx.25 PSI Approx.25 PSI Approx.25 PSI from Pump \ 4—from Pump 4—from Pump \ \ Metering Pin \ \ Le PSlan \ 20 to 22 PSI l \\\ \ All Pressure \ Equal IT.Discharge Line STo Discharge Line .�To Discharge Line 1.The Trip or Relaxed Position. Under nor- 2. Leak Sensing Position. As the pressure dicated by the PLD taking longer than mal operating conditions, it is assumed builds to approximately 20 to 22 psi,* two seconds to open completely. If that the lines are filled with gasoline. (rapidly), the piston has moved the pop- there is no leakage in the system, the When the system pressure is less than pet to such a position as to almost stop small flow around the metering pin in- 1 psi, the piston and poppet are in their the flow into the piping through the PLD creases the line pressure to 22 psi in "down" or "tripped" position. The posi- valve poppet. In this position, all the approximately two seconds at which tion of the valve poppet is such as to flow must then travel around the meter- point the piston will snap the poppet to allow approximately 11/2 to 3 GPM flow ing pin which limits it to approximately Position 3, allowing full flow. Any prod- into the delivery line through a bypass 3 GPH rate. If a simultaneous loss from uct relieved through pressure relief opening in the PLD valve poppet when the system equals or exceeds this valve during trip position will be vented the submersible pump starts. Since the amount, the line pressure will not build through vent tube to tank. This allows system is full, pressure builds rapidly beyond this point and the valve will re- piston to move freely with no back and the poppet moves to the leak sens• main in the leak sensing position with pressure to hamper its movement. ing pcoition assuming there is no leak the main flow blocked. If there is an at- 3. Non-Leak Position. This position allows present. The pressure relief valve pre- tempt to dispense while the valve is in full flow. The poppet will remain in this vents any build up of pressure under this position, the line pressure will drop, position as long as the system pressure piston when in trip position by allowing the piston will respond, and the poppet remains above 1 psi. At less than 1 psi, relief of trapped product. will return to Position 1 where the 11/2 the poppet will return to Position 1 and to 3 GPM will flow to the dispensers. the next time the pump is activated, the Leaks smaller than 3 GPH will be in- PLD will perform a line test. 'FOR FLD TO OPERATE PROPERLY, SUBMERSIBLE PUMPING UNIT MUST BE ABLE TO PRODUCE A MINIMUM OF 22 PSI. 0 RED JACKET' PUMPS A Wle,'Purtp 7_� 5600 F-fidpo b.,M-i KS 66202,(913)722 1AM RJ-3?