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Guide Specification For Duplex Supply
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Use the following suggested specification in those mission-critical situations where duplex (2) supply pumps and (1) return pump are required to maintain fuel supply and where the main storage tank is on the same level as the day tank. 2.04 DOUBLE WALL FUEL OIL DAY TANK WITH RUPTURE CONTAINMENTA. Provide a ____ gallon double wall rectangular day tank with 135% outer rupture chamber constructed of reinforced 10 gauge steel, with channel side supports, 1" NPT drains for primary and secondary tank, 4" NPT inspection/emergency vent ports, visual fuel level gauge, vent cap, and a 2" lockable manual fill cap. Tank interior shall be epoxy-coated and exterior shall be finished in an oil-resistant textured enamel. Day tank shall be per UL 142 specifications as manufactured by Phillips Pump LLC, Bridgeport CT. B. Tank connections shall include 1" fuel inlets, 1" NPT engine supply and engine return ports, required vent openings, 2" NPT manual fill, and 1" overflow port. Fuel oil supply inlet, engine return and engine supply ports shall have extended drop tubes to prevent surging in the day tank. C. Provide day tank level control probe arranged to monitor the fuel oil level. Probe shall be designed for installation in the top of the tank to control high-level alarm/return pump on, supply pumps off, lead supply pump on, low-level alarm/lag supply pump on and critical low-level conditions. D. Provide (2) fuel oil supply pumps with a capacity of not less than ___ GPM @ ___ PSIG discharge pressure when operating with diesel fuel. Each pump shall be close coupled to a ____ HP, ____ RPM open drip-proof motor. Pumps and motors shall be mounted on tank top and hard-piped into tank top. Each supply pump suction shall include a normally closed solenoid valve which will open when that supply pump is engaged. E. Provide a fuel oil return pump with a capacity of not less than ___ GPM @ ___ PSIG discharge pressure when operating with diesel fuel. Pump shall be close coupled to a ____ HP, ____ RPM open drip-proof motor. Pump and motor shall be mounted on tank top and hard-piped into tank top. F. Provide in secondary containment a rupture basin float switch with alarm and pump shut down which functions upon detection of oil in the rupture basin. G. Provide pump set-mounted system control cabinet to monitor and control the fuel oil delivery system in response to day tank demand. Cabinet shall be completely pre-wired, tested and shipped as an integrated system to insure jobsite reliability and shall be capable of operating on ____ volt, ____ phase, 60 Hz electrical service. Control strategy shall be microprocessor-based. Enclosure shall be constructed of a minimum of 14 gauge steel, continuously welded and constructed to NEMA 1 standards. Cabinet interior and exterior shall be primed and finished in a durable chemical-resistant enamel suitable for industrial environments. PLC shall have sufficient I/O to accomplish all necessary control functions. The control strategy shall be burned into an EPROM at the factory, and shall be safeguarded against re-configuration by unauthorized or unqualified personnel. All cabinet front devices shall be identified by black phenolic labels with engraved white lettering. Cabinet shall consist of but not be limited to the following:
Operation: As the fuel in the day tank is consumed by the generator and the level drops, the lead supply pump shall engage when the supply pump on float makes on drop. The lead supply pump shall remain engaged until the supply pump off float breaks on rise. The system will automatically alternate the supply pumps upon each successive demand call of the day tank. If a supply pump is removed for service or turned off, the system shall automatically select the opposite supply pump when called to engage per the demands of the day tanks. Low Level Alarm: If the fuel level continues to drop in the day tank while the lead supply pump is engaged, the lag supply pump on float will make on drop and the system will engage the lag supply pump. The alarm will sound and the system will display a low level alarm condition. Critical Low Level Alarm: If the fuel level continues to drop in the day tank with the lead and lag supply pumps engaged, the critical low level float will make on drop. The alarm will sound and the system will display a critical low level alarm condition. High Level Alarm: If fuel continues to rise in the day tank, the high level float will make on rise. The system will sound the alarm and display a high level warning. The supply pumps will be locked out until the alarm condition is cleared and the system is reset. Rupture Basin Leak Detected: If the leak sensor located in the day tank's rupture basin detects fuel, the system will sound the alarm and display a day tank rupture basin leak warning. The supply pumps will be locked out until the alarm condition is cleared and the system is reset. |
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