Stop or shut off fuel flow (ON/OFF). Acts as a cross feed valve for fuel feed from one engine to another.
Fuel valves
A kind of valve that has a detente gate and a SPRING LOADED pin gives a positive click or feel when the valve is in the correct position.
Manual (CONE TYPE)
A manual valve that has a NOTCH that also give a positive detente feel that the valve is in correct position.
Manual (POPPET TYPE)
Uses electric motors to operate fuel system valves and used for larger aircraft and remotely operated.
Two way motor for open and close (3 wires: 2 positive and one ground)
Motor-Operated valves
IN ONE TYPE AN ELECTRIC MOTOR ROTATES A DRUM OR BALL WHICH HAS DRILLED PASSAGES; WHEN THE DRUM ROTATES 90º THE PASSAGES LINE UP WITH THE INLET AND OUTLET AND THE FUEL CAN FLOW THROUGH; THE VALVE ROTATES BACK 90º TO SHUT OFF THE FLOW
Ball Valve
ANOTHER TYPE USES A SLIDING GATE; WHEN THE GATE IS OVER THE VALVE OPENING THERE IS NO FUEL FLOW; WHEN THE MOTOR SLIDES THE GATE BACK FROM THE OPENING FUEL CAN FLOW
Gate Valve
A SPRING LOADED PIN KEEPS THE VALVE OPEN SO THE SOLENOLID CAN BE DE-ENERGIZED (SAVE FROM OVERHEATING)
THE PIN IS RETRACTED BY A SECONDARY SOLENOID COIL ALLOWING THE SPRING-LOADED VALVE TO CLOSE
Solenoid Operated valves
- PROVIDE A POSITIVE PRESSURE AT THE INLET SIDE OF THE ENGINE DRIVEN PUMP
- BACK UP FOR ENGINE DRIVEN PUMP
- USED FOR STARTING
- TAKEOFF – LANDING
- SWITCHING TANKS
- HIGH ALTITUDE OPERATIONS
- TRANSFER FUEL
- DUMPING FUEL
Hand - Operated Pumps
- DRAWS FUEL INTO THE CENTER OF A CENTRIFUGAL IMPELLER AND EXPELLING IT AT OUTER EDGE
- THIS ARRANGEMENT ELIMINATES THE NEED FOR A BYPASS
Centrifugal boost pump or variable displacement pump
Type of pump that uses bernouli’s principle.
Normally used for engine feed or for scavenge.
USES PRESSURIZED FUEL FROM THE AUX PUMP OR THE EDP FLOWS THROUGH THE VENTURI CAUSING A LOW PRESSURE AREA WHICH DRAWS IN FUEL FROM THE TANK
Ejector pumps (Jet pumps/Venturi pump)
PRESSURIZED FUEL FLOW COMES UPSTREAM FROM THE EJECTOR PUMP AND IS KNOWN AS _______.
Motive flow
- LESS EXPENSIVE THAN CENTRIFUGAL PUMPS
- USES A SOLENOID AND SPRING TO CAUSE A PISTON TO MOVE UP AND DOWN AND PUMP FUEL
Electric pulsating pumps (Click - Clack)
PUPOSE IS TO DELIVER A CONTINUOUS SUPPLY OF FUEL AT THE PROPER PRESSURE AT ALL TIMES DURING ENGINE OPERATION
Engine Driven Pump (EDP)
Pump that HAS A CHAMBER WITH A DIAPHRAGM TO COMPENSATE FOR ALTITUDE OR IF ENGINE IS SUPERCHARGED FOR PROPER FUEL DELIVERY
Vane Pumps
-USED IN TUBINE ENGINE AIRCRAFT
-PROTECTS FUEL SYSTEM FROM ICE CRYSTALS
(WATER IN FUEL FREEZES INTO ICE CRYSTALS)
- OPERATES AS A HEAT EXCHANGER
- CAN USE HEAT FROM OIL OR BLEED AIR
FUEL HEATER
Indication requiring no electric power
direct reading
Indication were a float attached to an indicator
AS FLUID LEVEL CHANGES THE NEEDLE ON GAGE CHANGES
Mechanical reading
GLASS OR PLASTIC TUBE PLACED ON THE SAME LEVEL AS TANK
THE LEVEL OF TANK IS SHOWN BY THE FLUID LEVEL IN THE TUBE
Sight glass
- AS FUEL LEVEL CHANGES THE FLOAT OPERATED TRANSMITTER ELECTRICALLY SIGNAL CHANGES WHICH IS SHOWN AS A CHANGE ON THE GAGE IN THE COCKPIT
- INDICATOR MAY BE LOCATED AT ANY DISTANCE FROM THE GAGE
- NEW DIGITAL INSTRUMENTATION SYSTEMS CONVERT IT TO A DIGITAL SIGNAL
Resistance type
INSTEAD OF FLOATS THEY USE THE DI-ELECTRIC PROPERTIES OF FUEL AND AIR TO GET FUEL QUANTITY
- TANK TRANSMITTER IS A SIMPLE CAPACITOR
- A CAPACITOR IS A DEVICE THAT STORES ELECTRICITY
Capacitor type
- UNLOCK FROM WING AND SLOWLY LOWER THE TUBE UNTILL IT STOPS BY THE MAGNET OR STARTS TO DRIP
- READING IS TAKEN OFF SIDE OFF TUBE
- CAN BE CALIBRATED IN INCHS”, GALLONS, OR KG
Magnetic Drip Stick
DIFFERENTIAL PRESSURE SWITCH SENSES BEFORE (P1) AND AFTER (P2) FILTER PRESSURE (ΔP=P1-P2)
SWITCH CLOSES TO GROUND AND ILLUMINATES FLITER BYPASS CAUTION LIGHT BEFORE FILTER GOES INTO BYPASS (IMPENDING BYPASS)
Fuel filter bypass
