RU2141049C1 - Gas-turbine engine fuel drainage system - Google Patents

Abstract

FIELD: mechanical engineering; gas-turbine engines. SUBSTANCE: fuel drainage system of gas-turbine engine has drain tank, fuel pumping out main line with fuel pump connected to tank and fuel bypass main line. Drain tank has float valve. Fuel bypass main line is connected by one end with fuel pump outlet and by other end, with float valve, valve opening and closing levels being arranged higher than intake hole level. EFFECT: prevention of air getting into fuel pump inlet. 1 dwg

Description

 The invention relates to the field of aircraft engine manufacturing.

 Known drainage system of a gas turbine engine containing a drain tank connected to the tank and to the fuel system of the engine, a fuel pumping line with a shut-off valve and an ejector installed therein, and a fuel level sensor located in the tank and connected to the shut-off valve [1].

 A disadvantage of the known system is its structural complexity and low reliability of electrical units.

 Closest to the technical nature of the claimed is the fuel drainage system of a gas turbine engine (GTE), containing a drain tank connected to it through a suction port, a pumping line with a fuel pump, a fuel bypass line [2]. After fuel is pumped out of the drainage tank, the gear pump is maintained by circulating a mixture of fuel and air in the system. However, if the pump is rigidly connected to the rotor of the engine, then the duration of the pump operation on the fuel-air mixture can be more than 99% of the engine resource, since pumping out the "clean" fuel does not exceed several minutes immediately after starting. Long work on a mixture of fuel with air leads to premature wear of the pump parts and its failure.

 The technical problem solved by the invention is to increase the reliability of the fuel drainage system by eliminating air from entering the fuel pump.

 This problem is solved due to the fact that in the fuel drainage system of a gas turbine engine including a drain tank connected to it through an intake hole, a pumping line with a fuel pump, a fuel bypass line, according to the invention, a drain tank is equipped with a float valve, the fuel bypass line is connected at one end with the exit of the fuel pump, and the other with a float valve, made with the placement of the levels of its opening and closing above the level of the intake hole.

 In the claimed design, the drainage tank is equipped with a float valve, which is arranged to open and close above the intake hole of the drainage tank, and the fuel bypass line is connected at one end to the fuel pump outlet and the other to the float valve, which prevents complete pumping of fuel from drainage tank by ensuring bypass fuel inside the system and eliminates the ingress of air at the entrance to the fuel pump, thereby reducing wear of the rubbing surfaces of the parts.

 The drawing shows a diagram of the fuel drainage system of the gas turbine engine.

 The system includes a drainage tank 1 connected to it through a suction port 2 and to the fuel system 3 of the engine, a fuel pumping line 4 with a fuel gear pump 5, a filter 6 and a check valve 7 installed in it, and a fuel bypass line 8. The bypass line 8 is connected at one end to the output of the fuel pump 5, and the other to the float valve 9. The opening and closing levels of the valve 9 are located above the level of the intake hole 2. The drain tank 1 is connected to the drain lines 10 of the fuel from the drained engine cavities and venting 11. The pump 5 has a mechanical drive 12 from the rotor of the engine.

 The inventive system operates as follows.

 From the drained cavities of the engine, the fuel is discharged along the line 10 into the drainage tank 1, which leads to the closure of the float valve 9. When the engine is running, the fuel through the intake opening 2 enters the pumping line 4 and is pumped by the pump 5 through the filter 6 and the opened check valve 7 into the fuel system 3. Since the float valve 9 is closed, there is no bypass of fuel from the output of the pump 5 to the tank 1.

 As the pump is evacuated, the fuel level in the tank 1 decreases, and the freed space is filled with air through the venting line 11. At a certain level of fuel, the float valve 8 opens, fuel bypass starts on line 8 due to the gear pump 5 to the drain tank 1.

 This leads to a decrease in pressure behind the pump, closing the check valve 7 and the termination of the removal of fuel into the fuel system 3.

 With the continued flow of fuel through line 10 into the drain tank 1, the fuel level in it will increase, and the float valve 9 will close again. Turning off the fuel bypass will cause an increase in pressure behind the pump 5, the opening of the check valve 7 and the removal of the fuel received in the tank 1 to the fuel system 3.

 If fuel does not enter the drain tank 1, then the pump 5 provides fuel pumping inside the system from the tank 1 along the pumping lines 4 and bypass 8 back to the tank 1.

 The filter 6 purifies the fuel supplied to the fuel system, and the check valve 7 does not allow the fuel to flow back from the fuel system to the drain.

 Thus, the proposed fuel drainage system eliminates the ingress of air to the inlet of the fuel pump and thereby reduce wear of the rubbing surfaces of the parts, improving the operating conditions of the pump and increasing the reliability of the system.

Sources of information:
1. The magazine "Aviation industry", 1995, N 7-8, p. 22, Fig.5b.

 2. RF patent N 826780, F 02 C 3/24, 1993

Claims (1)

 A fuel drainage system of a gas turbine engine, including a drain tank connected to it through an intake port, a pumping line with a fuel pump, a fuel bypass line, characterized in that the drain tank is equipped with a float valve, a fuel bypass line is connected at one end to the fuel pump outlet and the other to with a float valve made with the placement of the levels of its opening and closing above the level of the intake hole.