A centrifugal booster pump for an aircraft fuel system and a method of oil-free maintenance thereof

Abstract

This invention discloses a centrifugal booster pump for aircraft fuel systems and its maintenance-free method, belonging to the field of aircraft fuel system design technology. The centrifugal booster pump includes a pump housing and a pump core. The pump housing is a purely mechanical structure, fixedly installed at the bottom opening of the aircraft fuel tank, and integrates a self-sealing valve assembly. The pump core is detachably connected to the pump housing and includes a DC brushless motor and an impeller driven by the motor. When the pump core is installed inside the pump housing, it mechanically opens the self-sealing valve assembly, allowing fuel to enter. When the pump core is disassembled, the self-sealing valve assembly automatically resets and closes, isolating the fuel outside the pump housing, achieving maintenance-free operation. This invention, through the separate design of the pump core and housing, the integration of the self-sealing valve, and the application of a brushless motor, simultaneously solves the problems of needing to drain fuel and periodically replace carbon brushes during the maintenance of traditional centrifugal booster pumps, significantly improving the maintainability and economy of the product.

Description

Technical Field

[0001] This invention relates to aircraft fuel system design technology, and in particular to a centrifugal booster pump with a separable pump core and housing for an aircraft fuel system, and a maintenance method that eliminates the need for draining fuel. Background Technology

[0002] The centrifugal booster pump in an aircraft fuel system is a critical component ensuring reliable fuel supply to the engine. In existing technology, traditional centrifugal booster pumps typically employ a one-piece structure, meaning the pump housing and pump core are inseparable. When maintenance or repair is required, the fuel in the fuel tank must first be completely drained before the entire pump can be removed from the bottom of the tank. This process is cumbersome, time-consuming, and the drained fuel requires special handling, resulting in significant waste and economic losses.

[0003] Furthermore, traditional centrifugal booster pumps mostly use brushed DC motors as their power source. The carbon brushes of brushed motors are consumable parts and need to be replaced periodically after the pump has been running for a certain period. Replacing the carbon brushes also requires disassembling the entire pump body, further increasing the complexity of maintenance and downtime.

[0004] In summary, the maintainability and economy of existing centrifugal booster pumps cannot meet the increasingly demanding requirements of users. Therefore, it is crucial to research a new type of centrifugal booster pump that allows for pump core maintenance without the need for fuel emissions and eliminates the need for periodic carbon brush replacements. Summary of the Invention

[0005] The purpose of this invention is to provide a centrifugal booster pump for aircraft fuel systems and a method for maintenance without draining fuel, so as to solve the technical problems of existing centrifugal booster pumps requiring fuel draining and regular carbon brush replacement during maintenance, thereby improving the maintainability and economy of the product.

[0006] The technical solution of this invention is implemented as follows: In a first aspect, the present invention provides a centrifugal booster pump for an aircraft fuel system, comprising: The pump housing component, which is a purely mechanical structure, is used for fixed installation at the bottom opening of the aircraft fuel tank, and the pump housing component integrates a self-sealing valve assembly; A pump core assembly, which is detachably connected to the pump housing assembly, the pump core assembly including a brushless DC motor and an impeller driven by the brushless DC motor; When the pump core component is installed inside the pump housing component, the pump core component mechanically pushes open the self-sealing valve assembly, allowing fuel in the fuel tank to enter the pump core component; when the pump core component is removed from the pump housing component, the self-sealing valve assembly automatically resets and closes, so as to isolate the fuel in the fuel tank outside the pump housing component, achieving maintenance without draining fuel.

[0007] As a further technical solution of the present invention: the self-sealing valve assembly includes a valve core, a valve sleeve, and a spring; one end of the spring abuts against the valve sleeve, and the other end abuts against the valve core, for providing an elastic force to the valve core toward the closed position; when the pump core component is installed, the pump core component overcomes the elastic force of the spring and pushes the valve core to the open position; when the pump core component is disassembled, the spring drives the valve core to automatically reset to the closed position.

[0008] As a further technical solution of the present invention: the controller of the brushless DC motor is integrated inside the pump core component, and the pump core component is filled with fuel for cooling the brushless DC motor.

[0009] As a further technical solution of the present invention: the pump core component further includes an oil inlet and an inducer wheel, the inducer wheel being disposed upstream of the impeller to improve the cavitation resistance of the pump core component.

[0010] As a further technical solution of the present invention: the pump housing component is installed at the bottom of the aircraft fuel tank by means of a mounting flange and a sealing gasket, and the outlet pipe joint of the pump housing component is sealed to the pipeline on the aircraft by means of a sealing ring.

[0011] As a further technical solution of the present invention: at least one sealing ring is provided on the outside of the pump core component to prevent fuel from entering the controller of the brushless DC motor.

[0012] Secondly, the present invention provides a maintenance-free method for a centrifugal booster pump in an aircraft fuel system, wherein the centrifugal booster pump includes a pump housing component and a pump core component, the pump housing component integrating a self-sealing valve assembly and being fixedly installed at the bottom of the aircraft fuel tank, and the method includes the following steps: Disassembly steps: The pump core component is pulled out axially from the pump housing component. The self-sealing valve assembly automatically closes under the action of elastic force, isolating the fuel in the fuel tank outside the pump housing component, thereby removing the pump core component without discharging the fuel in the fuel tank. Installation steps: Insert the new or maintained pump core component axially into the pump housing component. The pump core component mechanically pushes open the self-sealing valve assembly, allowing fuel in the fuel tank to enter the pump core component and restore the boost function.

[0013] As a further technical solution of the present invention: the self-sealing valve assembly includes a valve core, a valve sleeve, and a spring; in the disassembly step, the pump core component releases the pressure on the valve core, and the spring drives the valve core to move from the open position to the closed position; in the installation step, the pump core component overcomes the elastic force of the spring and pushes the valve core to move from the closed position to the open position.

[0014] As a further technical solution of the present invention: the pump core component uses a DC brushless motor as a power source, so there is no need to replace the carbon brushes in the disassembly step and the installation step.

[0015] As a further technical solution of the present invention: after the installation step, a power supply start-up step is also included: power is supplied to the DC brushless motor in the pump core component, the motor drives the impeller to rotate at high speed, and outputs fuel that meets the flow and pressure requirements within 5 seconds.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Maintenance without draining fuel: By designing the centrifugal booster pump as a separable pump housing and pump core assembly, and integrating a self-sealing valve assembly in the pump housing assembly, when the pump core needs maintenance, simply pull out the pump core, and the self-sealing valve will automatically close, isolating the fuel in the fuel tank. The pump core can be disassembled and replaced without draining the fuel, which greatly improves maintenance efficiency and reduces maintenance costs and fuel waste.

[0017] 2. No need to replace carbon brushes: The pump core components use a DC brushless motor instead of a traditional brushed motor, eliminating the need for regular replacement of carbon brushes due to wear, improving the reliability and service life of the pump, and further reducing the maintenance cost throughout the entire life cycle.

[0018] 3. Fuel cooling: The pump core is filled with fuel, which directly cools the brushless DC motor without the need for an additional cooling structure, simplifying the design and improving heat dissipation efficiency.

[0019] 4. Simple and reliable structure: The pump housing is a purely mechanical structure with no electrical components, resulting in a low probability of failure; the self-sealing valve assembly adopts a spring reset structure, ensuring reliable operation and good sealing.

[0020] 5. Quick start: Driven by a brushless motor, it starts quickly and can output the required fuel pressure and flow within 5 seconds to ensure timely fuel supply to the engine.

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 This is a structural cross-sectional view of the pump housing component in an embodiment of the present invention; Figure 2 This is a schematic diagram of the pump core component in an embodiment of the present invention; Figure 3 This is a cross-sectional view of the overall installation of the centrifugal booster pump in an embodiment of the present invention (pump core inserted into the housing, self-sealing valve open). Figure 4 This is a schematic diagram of the self-sealing valve in the closed state (after the pump core is removed) in an embodiment of the present invention. Figure 5 This is a schematic diagram showing the pump core component and the outer casing component in a separated state in an embodiment of the present invention; Figure 6 This is a schematic diagram of the installation of a centrifugal booster pump on an aircraft fuel tank in an embodiment of the present invention; Figure 7 This is a schematic diagram of the working principle of the centrifugal booster pump in an embodiment of the present invention (showing the direction of fuel flow).

[0023] Figure reference numerals: 100 - Pump housing component; 101-Mounting housing; 102-Screw; 103-Plug; 104-Valve core washer; 105-Valve core; 106-Valve stem; 107-Sealing ring; 108-Spring; 109-Self-locking nut; 110-Washer; 111-Screw; 112-Sealing gasket; 113-Filter assembly; 114-Sealing ring; 115-Outlet pipe connector; 116-Screw; 117-Washer; 118-Protective cap; 200 - Pump core components; 201-DC brushless motor; 202-Sealing ring; 203-Impeller; 204-Oil inlet; 205-Sealing ring; 206-Drain plug; 207-Sealing ring; 208-Sealing ring; 209-Counterhead screw; 210-Self-locking nut; 211-Washer; 212-Inducer wheel; 213-Semi-circular key; 214-Adjusting washer; 215-Pump core housing; 216-Rubber plug; 217-Controller. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some embodiments of this invention, but not all embodiments.

[0025] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0026] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0027] The following is in conjunction with the appendix Figure 1-7 The embodiments of the present invention will be described in detail below.

[0028] Example 1: Structure of a centrifugal booster pump like Figures 1 to 7 As shown, this embodiment provides a centrifugal booster pump for an aircraft fuel system, including a pump housing component 100 and a pump core component 200. The pump housing component 100 is a purely mechanical structure and is fixedly installed at the bottom opening of the aircraft fuel tank; the pump core component 200 is detachably connected to the pump housing component 100 and is the main working component of the booster pump.

[0029] I. Structure of Pump Housing Component 100 like Figure 1 As shown, the pump housing component 100 mainly includes a mounting housing 101, an outlet pipe connector 115, a self-sealing valve assembly (composed of a valve core 105, a valve sleeve, a valve stem 106, a spring 108, etc.), a filter assembly 113, a sealing gasket 112, etc.

[0030] The mounting housing 101 has a generally cylindrical structure, with a mounting flange at its upper end for vertically mounting the entire pump housing component 100 to the opening at the bottom of the aircraft wing fuel tank using screws (not shown in the figure). A sealing gasket 112 is provided between the mounting flange and the bottom surface of the fuel tank to prevent fuel leakage.

[0031] An outlet pipe connector 115 is provided on the side wall of the mounting housing 101. The outlet pipe connector 115 is fixed to the mounting housing 101 by screws 111 and is fitted with a sealing ring 114 for sealing connection with the fuel line on the aircraft. The internal channel of the outlet pipe connector 115 communicates with the oil collection chamber inside the mounting housing 101.

[0032] The self-sealing valve assembly is located at the lower inlet of the mounting housing 101 and includes a valve core 105, a valve stem 106, a valve sleeve (formed by a corresponding internal structure of the mounting housing 101), a spring 108, a valve core washer 104, and a self-locking nut 109. The valve stem 106 passes through the bottom of the mounting housing 101, and the upper end of the valve stem 106 is fixed to the valve core 105 by the self-locking nut 109 and the washer 110. The upper end face of the valve core 105 is provided with the valve core washer 104. The spring 108 is sleeved on the outside of the valve stem 106. The upper end of the spring 108 abuts against the valve sleeve (or the stepped surface inside the mounting housing 101), and the lower end abuts against the shoulder or washer of the valve stem 106, always applying an upward elastic force to the valve stem 106, so that the valve core 105 is tightly pressed against the valve seat in the free state and is in the closed position.

[0033] The lower end of the valve stem 106 extends out of the bottom of the mounting housing 101 to contact the pump core component 200. When the pump core component 200 is not installed, the valve stem 106 is in the upper position under the action of the spring 108, and the valve core 105 closes the oil inlet passage. The bottom of the mounting housing 101 is also provided with protective components such as a plug 103 and a protective cap 118.

[0034] The filter assembly 113 is located in the oil inlet channel to filter impurities in the fuel and prevent them from entering the pump core component 200.

[0035] II. Structure of Pump Core Component 200 like Figure 2 As shown, the pump core component 200 mainly includes a pump core housing 215, a DC brushless motor 201, a controller 217, an impeller 203, an inducer 212, an oil inlet 204, and sealing rings 202 and 208.

[0036] The pump core housing 215 is cylindrical, and its outer diameter is adapted to the inner diameter of the mounting housing 101, so that the pump core component 200 can be slidably inserted into the pump housing component 100. The lower end of the pump core housing 215 is provided with an oil inlet 204, which is fixed to the pump core housing 215 by countersunk screws 209 and is provided with a sealing ring 205 for sealing.

[0037] A brushless DC motor 201 is installed inside the pump housing 215. The stator of the brushless DC motor 201 is fixed to the inner wall of the pump housing 215, and the rotor shaft is supported by bearings. A controller 217 is integrated inside the pump housing 215, located below or to the side of the brushless DC motor 201, and is electrically connected to the motor. The wires of the controller 217 pass through wire holes and rubber plugs 216 on the pump housing 215 and exit to the outside of the pump component 200 for connecting to the aircraft power supply and control signals.

[0038] The rotor shaft of the DC brushless motor 201 extends upwards, and an impeller 203 is fixed to the shaft by a semi-circular key 213. The impeller 203 is locked in place by a washer 211 and a self-locking nut 210. Downstream of the impeller 203 (i.e., at the outlet side of the impeller 203), a spiral oil collecting chamber and a diffusion and pressurization section are formed inside the pump housing 215. Upstream of the impeller 203 (i.e., between the oil inlet 204 and the impeller 203), an inducer 212 is provided. The inducer 212 is also fixed to the motor shaft and is used to improve the pump's cavitation resistance under low inlet pressure conditions.

[0039] The pump core housing 215 is fitted with multiple sealing rings, including a sealing ring 202 located in the upper middle part and a sealing ring 208 located at the bottom. The sealing ring 202 is used to prevent fuel from entering the cavity where the controller 217 is located; the sealing ring 208 is used to prevent fuel from leaking to the outside of the fuel tank from the gap between the pump core component 200 and the pump housing component 100 after the pump core component 200 is inserted into the pump housing component 100.

[0040] The bottom of the pump core housing 215 is also provided with an oil drain plug 206 and a sealing ring 207, which are used to drain the residual oil inside the pump core component 200 when needed.

[0041] III. The mating relationship between the pump housing component 100 and the pump core component 200 like Figure 3 As shown, when the pump core assembly 200 is axially inserted into the pump housing assembly 100, the bottom of the pump core assembly 200 (i.e., the lower end face of the oil inlet 204) first contacts and pushes downward the lower end of the valve stem 106. The pump core assembly 200 overcomes the elastic force of the spring 108, pushing the valve stem 106 and valve core 105 downward, causing the self-sealing valve assembly to move from the closed position (e.g., ...). Figure 4 (As shown) Switch to the open position (e.g.) Figure 3 (As shown). At this time, the fuel inlet passage is opened, and the fuel in the fuel tank can pass through the filter assembly 113, the gap between the opened valve core 105 and the valve seat, and enter the fuel inlet 204 of the pump core component 200.

[0042] The pump core component 200 continues to be inserted until it is in place. At this point, the pump core component 200 and the pump housing component 100 are reliably sealed by the sealing rings 202 and 208. The outlet of the pump core component 200 (i.e., the outlet of the impeller 203) is connected to the oil collection chamber in the mounting housing 101, and then to the outlet pipe joint 115.

[0043] When it is necessary to disassemble the pump core component 200 for maintenance, such as Figure 4 and Figure 5 As shown, the operator pulls the pump core assembly 200 axially upwards. As the bottom of the pump core assembly 200 moves away from the valve stem 106, the valve stem 106 returns to its original position under the elastic force of the spring 108, causing the valve core 105 to press against the valve seat again, and the self-sealing valve assembly automatically closes. At this time, the fuel in the fuel tank is completely isolated outside the pump housing assembly 100 and will not leak from the pump's mounting opening. Therefore, the operator can safely remove the pump core assembly 200 for inspection or replacement without draining the fuel from the fuel tank.

[0044] IV. Working Principle like Figure 7As shown, the centrifugal booster pump in this embodiment is vertically mounted at the bottom of the aircraft fuel tank. When the aircraft power supply provides power to the DC brushless motor 201 through the controller 217, the DC brushless motor 201 drives the impeller 203 to rotate at high speed. The impeller 203 pushes the fuel in a circular motion, giving the fuel kinetic energy. Under the action of centrifugal force, the fuel is thrown into the spiral oil collecting chamber of the pump core housing 215, where part of the kinetic energy is converted into pressure energy. Subsequently, the fuel enters the diffusion booster section, where part of the kinetic energy is further converted into pressure energy, and finally discharged from the outlet pipe joint 115 at a certain pressure and flow rate to supply the engine fuel system.

[0045] Because a brushless DC motor 201 is used, the risk of sparks caused by commutation in brushed motors is avoided, and there is no need to replace carbon brushes regularly. At the same time, the pump core component 200 is filled with fuel, which flows directly over the motor surface to effectively cool the brushless DC motor 201, ensuring stable operation of the motor over a long period of time.

[0046] Tests have shown that the centrifugal booster pump in this embodiment can output the required fuel pressure and flow rate for the engine within 5 seconds of being powered on.

[0047] Example 2: Oil-free maintenance method This invention discloses a method for oil-free maintenance of the aforementioned centrifugal booster pump, comprising the following steps: Step S1: Disassembly Step When maintenance of the centrifugal booster pump is required, the operator does not need to drain the fuel from the fuel tank. First, disconnect the power and control signal connections of the pump core assembly 200. Then, using a tool, slowly pull the pump core assembly 200 axially upward from the pump housing assembly 100. During the extraction, the bottom of the pump core assembly 200 gradually disengages from the valve stem 106. The valve stem 106 moves upward under the elastic restoring force of the spring 108, causing the valve core 105 to press against the valve seat, and the self-sealing valve assembly automatically closes. The closed self-sealing valve assembly completely isolates the fuel in the fuel tank from the pump housing assembly 100, preventing fuel from flowing out of the pump mounting opening. Continue pulling out the pump core assembly 200 until it is completely removed, thus completing the pump core disassembly.

[0048] Step S2: Installation Steps Align the new or maintained pump core assembly 200 with the opening in the pump housing assembly 100 and insert it axially downwards. When the bottom of the pump core assembly 200 contacts the valve stem 106, continue pressing down. The pump core assembly 200 overcomes the spring force of the spring 108, pushing the valve stem 106 and valve core 105 downwards, gradually opening the self-sealing valve assembly. After the pump core assembly 200 is fully inserted, the self-sealing valve assembly is fully open, allowing fuel from the fuel tank to enter the pump core assembly 200. Simultaneously, the sealing rings 202 and 208 on the pump core assembly 200 form a reliable seal with the inner wall of the pump housing assembly 100, preventing fuel leakage.

[0049] Step S3: Power-on startup procedure Connect the power supply and control signal lines to the pump core assembly 200. Power is supplied to the DC brushless motor 201, which drives the impeller 203 to rotate at high speed, and the pump starts working, outputting fuel that meets the flow and pressure requirements within 5 seconds.

[0050] During the disassembly and installation process described above, since the pump core component 200 uses a DC brushless motor 201, no carbon brush inspection or replacement is required, further simplifying the maintenance process.

[0051] Industrial applicability: The centrifugal booster pump and its oil-drainage-free maintenance method provided by this invention are applicable to various aircraft fuel systems, especially fuel tank booster pumps for large civil airliners, transport aircraft, and military aircraft. Its oil-drainage-free and carbon brush-replacement-free features can significantly reduce aircraft maintenance costs, improve operational availability, and have promising industrial application prospects and economic benefits.

[0052] Example 3 This invention discloses a novel centrifugal booster pump for aircraft fuel systems that enables maintenance-free fuel draining. The pump housing structure comprises a mounting housing 101, screws 102, a plug 103, a valve core washer 104, a valve core 105, a valve stem 106, a sealing ring 107, a spring 108, a self-locking nut 109, washers 110, screws 111, sealing gaskets 112, a filter assembly 113, sealing rings 114, an outlet pipe connector 115, screws 116, washers 117, and a protective cap 118. The pump housing structure consists of a DC brushless motor 201 and its internal controller 217, a sealing ring 202, an impeller 203, an oil inlet 204, a sealing ring 205, an oil drain plug 206, a sealing ring 207, a sealing ring 208, a countersunk screw 209, a self-locking nut 210, a washer 211, an inducer 212, a semi-circular key 213, an adjusting washer 214, a housing 215, and a rubber plug 216. The function of the pump housing structure is to seal the fuel in the oil tank after the pump core structure is disassembled, and the pump core structure is the working component.

[0053] A new type of centrifugal booster pump, capable of maintenance-free operation without draining oil, is vertically installed at the bottom opening of the oil tank. After power-on, the DC brushless motor 201 drives the impeller 203 to rotate at high speed. The impeller 203 propels the fuel in a circular motion, giving the fuel kinetic energy. Under centrifugal force, the fuel is thrown into the spiral oil collecting chamber 215 of the casing, converting kinetic energy into pressure energy, and then flows into the diffusion booster section. In the diffusion section, some of the fuel's kinetic energy is further converted into pressure energy and discharged from the pump outlet at a certain pressure and flow rate, outputting fuel that meets the flow and pressure requirements within 5 seconds. During operation, fuel is introduced into the motor for cooling.

[0054] This system enables maintenance without draining fuel. The pump housing 101 is mounted on the bottom of the fuel tank via a mounting flange and sealed to the tank by a gasket 112. The fuel outlet connector on the pump housing, equipped with a sealing ring 114, is sealed to the aircraft's tubing. The fuel pump is vertically mounted to the bottom of the aircraft wing fuel tank using screws on the large end face of the mounting housing 201. The wires of the DC brushless motor 201 pass through a rubber plug from the wire hole inside the housing 215. The fuel inlet 204 is fixed to the housing 101 with screws. A sealing ring 202 is fitted over the pump core to prevent fuel from entering the controller 217. A sealing ring 208 at the bottom of the pump core prevents fuel leakage to the outside of the fuel tank. When the pump core assembly 200 is disassembled for maintenance, it is pulled out. The self-sealing valve core 105 of the pump housing assembly 100 pops out under the action of a spring 108, sealing the fuel inlet. Fuel from the fuel tank no longer enters the pump housing, thus achieving maintenance without draining fuel.

[0055] The present invention provides a centrifugal booster pump for aircraft fuel systems that enables maintenance-free operation by draining fuel. By using a brushless motor, the risk of commutation spark ignition associated with brushed motors is avoided, as is the need for periodic carbon brush replacement. The design of the pump housing and pump core assembly enables maintenance-free operation of the pump core through the self-sealing function of the pump housing. This improves the reliability, maintainability, and economy of the product.

[0056] Thus, the objective of this invention has been achieved.

[0057] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A centrifugal booster pump for an aircraft fuel system, characterized in that, include: The pump housing component, which is a purely mechanical structure, is used for fixed installation at the bottom opening of the aircraft fuel tank, and the pump housing component integrates a self-sealing valve assembly; A pump core assembly, which is detachably connected to the pump housing assembly, the pump core assembly including a brushless DC motor and an impeller driven by the brushless DC motor; When the pump core component is installed inside the pump housing component, the pump core component mechanically pushes open the self-sealing valve assembly, allowing fuel in the fuel tank to enter the pump core component; when the pump core component is removed from the pump housing component, the self-sealing valve assembly automatically resets and closes, so as to isolate the fuel in the fuel tank outside the pump housing component, achieving maintenance without draining fuel.

2. The centrifugal booster pump according to claim 1, characterized in that, The self-sealing valve assembly includes a valve core, a valve sleeve, and a spring; One end of the spring abuts against the valve sleeve, and the other end abuts against the valve core, for providing an elastic force to the valve core toward the closed position; When the pump core component is installed, it overcomes the elastic force of the spring and pushes the valve core to the open position; when the pump core component is disassembled, the spring drives the valve core to automatically reset to the closed position.

3. The centrifugal booster pump according to claim 1, characterized in that, The controller of the brushless DC motor is integrated inside the pump core component, and the pump core component is filled with fuel for cooling the brushless DC motor.

4. The centrifugal booster pump according to claim 1, characterized in that, The pump core component also includes an oil inlet and an inducer wheel. The inducer wheel is located upstream of the impeller and is used to improve the cavitation resistance of the pump core component.

5. The centrifugal booster pump according to claim 1, characterized in that, The pump housing component is mounted to the bottom of the aircraft fuel tank via a mounting flange and a gasket, and the outlet pipe joint of the pump housing component is sealed to the pipeline on the aircraft via a sealing ring.

6. The centrifugal booster pump according to claim 1, characterized in that, At least one sealing ring is fitted around the pump core component to prevent fuel from entering the controller of the brushless DC motor.

7. A maintenance-free method for a centrifugal booster pump in an aircraft fuel system, wherein the centrifugal booster pump comprises a pump housing component and a pump core component, the pump housing component integrating a self-sealing valve assembly and fixedly installed at the bottom of the aircraft fuel tank, characterized in that... The method includes the following steps: Disassembly steps: The pump core component is pulled out axially from the pump housing component. The self-sealing valve assembly automatically closes under the action of elastic force, isolating the fuel in the fuel tank outside the pump housing component, thereby removing the pump core component without discharging the fuel in the fuel tank. Installation steps: Insert the new or maintained pump core component axially into the pump housing component. The pump core component mechanically pushes open the self-sealing valve assembly, allowing fuel in the fuel tank to enter the pump core component and restore the boost function.

8. The oil-free maintenance method according to claim 7, characterized in that, The self-sealing valve assembly includes a valve core, a valve sleeve, and a spring; in the disassembly step, the pump core component releases the pressure on the valve core, and the spring drives the valve core to move from the open position to the closed position; in the installation step, the pump core component overcomes the elastic force of the spring and pushes the valve core to move from the closed position to the open position.

9. The oil-free maintenance method according to claim 7, characterized in that, The pump core component uses a DC brushless motor as its power source, so there is no need to replace the carbon brushes during the disassembly and installation steps.

10. The oil-free maintenance method according to claim 7, characterized in that, Following the installation steps, a power supply start-up step is also included: powering the DC brushless motor inside the pump core component, the motor drives the impeller to rotate at high speed, and outputs fuel that meets the flow and pressure requirements within 5 seconds.

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