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Explain pump type and working principle
- -Single Stage
Power supplied to pump through the use of a split shaft gear located in the drive line between the transmission and rear axle
Power is shifted from the rear axle and up to pump transmission via shift collar activated by pneumatic shift.
What is a centrifugal pump
Centrigugal force is created by a spinning disk (impeller).
The faster it spins, the greater the psi.
Basic two parts are the impeller and the casing
3 ways to influence pump discharge pressure
- 1. Amount of water being discharged
- 2. Speed of the impeller
- 3. Pressure of water from a pressurized source (Hydrant, Relay)
5 Basic parts of impeller and casing
- 1. Eye
- 2. Vane
- 3. Volute
- 4. Casing
- 5. Discharge
Trace a drop of water
- Enters thru the scree (self-sacrificing anode) and past the 5" gate valve
- Into the eye of the impeller
- Then thrown into the volute by the impeller and the vanes.
- Once water reaches the discharge side, water is pushed out of a discharge port depending on which ball valve is open.
Explain discharge ports, number, sizes and location.
- Six 2 1/2" discharge ports
- One 3" discharge port (LDH)
- Two pre-plumbed hotlines
- Deck gun
- Booster line
- Discharges 1 and 2: Driver side
- Discharge 3 (LDH): Captain Side
- Discharge 4 and 5: Captain Side
- Discharge 6 (Foam) and 7: Rear
Explain pump capacity rating
Explain pressure relief valve and the working principle
- TPM relief valve is a mechanical system, consisting of
- 1) an internal relief valve
- (QG-recirculating) which bypasses water to the suction side of the pump,
- 2) an external relief (dump) valve (PG30, w/sensing valve attached), and
- 3) a single panel mounted control valve (PMD) to provide control of pump
- TPM relieves pressure by first
- utilizing the internal relief valve (QG), returning flow to the pump suction.
- If excessive pressure remains,
- secondary external relief valve (PG30) responds by discharging excess
- pressure to the atmosphere.
Explain primer pump, type, and location
- Rotary Vane Positive
- Displacement pump
- Creates vacuum; designed to
- evacuate air in suction hose and the pump
- Allows atmospheric pressure to
- push water from open source through suction hose and into pump.
Identify and define all components
of the pump panel
Master discharge pressure – 0 to 600 psiTachometer – 0-300rpm, max @ 2100, idle@700, draft@1000-1500rpmEngine coolant temp – Normal operating temperature: 180 – 200 degrees (but usually 175).Oil pressure indicator – Min. 10psi @ 700rpm (idle) and 35-45psi @ 2100rpmVoltmeter- 13.6 – 14.2 VDCDischarge valves – 0- 400 psi (2 ½”) Primer controlTank to pump valveTank fill valveWater tank level indicatorHigh Temperature Warning lightLow Oil warning lightPump hours meter