Air guide valve of APU

Abstract

The utility model discloses an air guide valve of an APU (auxiliary power unit). The air guide valve comprises a shell, a valve, an electromagnetic valve and an air actuator, the gas taking bypass connected to the pneumatic actuator from the gas taking port comprises a first gas taking bypass and a second gas taking bypass, and the first gas taking bypass and the second gas taking bypass are connected between the gas taking port and the pneumatic actuator in parallel; the APU air guiding valve further comprises an air filter arranged in the first air taking bypass. The flow direction control valve is arranged at the downstream of the air taking port, and the flow direction control valve is arranged to operate to open the second air taking bypass when the air filter fails; and the air filter detection device is used for detecting whether the air filter fails or not. According to the air guide valve of the APU, the situation that a downstream electromagnetic valve and a pneumatic actuator are affected by pollutants or impurities in air flow to cause clamping stagnation and even failure can be effectively prevented, and the working reliability of the APU is guaranteed.

Description

Technical Field

[0001] This utility model relates to the technical field of auxiliary power and force devices for aircraft, and more specifically, to an APU bleed air valve. Background Technology

[0002] The APU (Auxiliary Power Unit) is an important system on an aircraft, primarily used to provide electrical, hydraulic, and pneumatic support on the ground or in the air. The APU bleed air valve is a key component of the APU system; its function is to control the supply of bleed air from the APU to the aircraft's pneumatic system, ensuring a stable pneumatic supply for the aircraft under various operating conditions.

[0003] like Figure 1 As shown, common APU bleed valves include pneumatic butterfly valves, which consist of three core parts: a butterfly valve, a pneumatic actuator, and electrical components. Each part plays a crucial role in the valve's operation.

[0004] In the initial state, when the pneumatic system is not pressurized, there is no air pressure in the chamber of the pneumatic actuator of the APU bleed valve. At this time, the return spring pushes the actuator piston, keeping the butterfly valve in the closed position. This design ensures that the valve can automatically close in the event of system failure or insufficient air pressure, preventing gas leakage or system malfunction. When the solenoid valve is not energized, the valve core is in the closed state. At this time, the bleed air to the actuator opening chamber will be discharged through the valve core, resulting in insufficient bleed air entering the actuator opening chamber. Since the air pressure cannot push the actuator, the butterfly valve remains in the closed position. This mechanism ensures that the valve will not open accidentally when the solenoid valve is not activated, thus maintaining the safety and stability of the system. When the solenoid valve is energized, the valve core is opened, stopping the exhaust. At this time, gas can smoothly enter the actuator opening chamber, forming sufficient air pressure to drive the actuator. As the actuator moves, the butterfly valve plate is opened, allowing bleed air to enter the air supply system. This process realizes the valve's transition from closed to open, ensuring that the system can obtain the required bleed air as needed. In summary, the APU bleed air valve achieves precise control of the bleed air system through the coordinated operation of the pneumatic actuator and the solenoid valve.

[0005] However, in the current APU bleed valve, as airflow enters the pneumatic actuator, the bearings and electrical components of the pneumatic actuator are easily contaminated by dust and other pollutants in the air, leading to jamming, unstable performance, functional failure, and other malfunctions, resulting in phenomena such as high opening pressure, inability to close, and poor contact of the position sensor.

[0006] Furthermore, in current APU bleed air valves, the valve's position is determined by a microswitch at the end of the butterfly shaft's operating stroke. This switch indicates the valve's position: closed or open. It cannot detect an APU bleed air valve stuck in the half-open position. However, this state leads to low bleed air pressure, potentially hindering main engine start-up and environmental control bleed air functions. This fault mode is difficult to detect and complicates troubleshooting. Utility Model Content

[0007] To overcome the shortcomings of the prior art, this utility model provides an APU bleed air valve, comprising: a housing having an air intake port; a valve rotatably disposed within the housing; a pneumatic actuator connected to the valve via a shaft and connected to the air intake port via an air intake bypass, the pneumatic actuator being configured to reciprocate the shaft in the presence of gas from the air intake port; a solenoid valve configured to control the airflow entering the pneumatic actuator from the air intake port; wherein the air intake bypass connecting the air intake port to the pneumatic actuator includes a first air intake bypass and a second air intake bypass, the first and second air intake bypasses being connected in parallel between the air intake port and the pneumatic actuator; the APU bleed air valve further comprises: an air filter disposed in the first air intake bypass; a flow direction control valve disposed downstream of the air intake port, the flow direction control valve being arranged to open the second air intake bypass when the air filter fails; and an air filter detection device for detecting whether the air filter has failed.

[0008] By employing the APU bleed valve according to the present invention, it is possible to effectively prevent downstream solenoid valves and pneumatic actuators from being affected by pollutants or impurities in the airflow, thus preventing them from becoming stuck or even failing, and ensuring the reliability of APU operation.

[0009] According to one aspect of the present invention, the flow control valve includes a bypass valve disposed in a second air intake bypass, the bypass valve being connected in parallel with the air filter, the inlet of the bypass valve being connected to the air intake port, and the outlet of the bypass valve being connected to the pneumatic actuator.

[0010] According to another aspect of the present invention, the air filter detection device includes a differential pressure sensor, which includes a high-pressure port and a low-pressure port, respectively connected to the upstream and downstream positions of the air filter to detect the pressure difference between the upstream and downstream of the air filter. When the pressure difference detected by the differential pressure sensor exceeds a preset differential pressure threshold, the bypass valve is opened.

[0011] According to another aspect of the present invention, the APU bleed valve further includes a position switch configured to indicate the fully open position of the valve and the fully closed position of the valve, respectively.

[0012] By setting a position switch that can indicate both the fully closed and fully open positions of the valve, the fault mode of the APU bleed valve stuck in the half-open position can be identified in a timely manner, and relevant alarms can be issued to improve safety.

[0013] According to another aspect of the present invention, the position switch includes a fully open triggering part indicating that the valve is fully open and a fully closed triggering part indicating that the valve is fully closed. A swing arm is fixed to the shaft and rotates with the shaft. When the shaft drives the valve to rotate to the fully open position, the swing arm triggers the fully open triggering part; when the shaft drives the valve to rotate to the fully closed position, the swing arm triggers the fully closed triggering part.

[0014] According to another aspect of the present invention, the position switch includes a non-contact first sensing switch and a second sensing switch. When the valve is rotated to the fully open position, the first sensing switch is triggered, and when the valve is rotated to the fully closed position, the second sensing switch is triggered.

[0015] According to another aspect of the present invention, the solenoid valve is disposed downstream of the confluence of the first and second gas intake bypasses and upstream of the pneumatic actuator.

[0016] According to another aspect of the present invention, the solenoid valve has a valve core and a valve body, the valve body is provided with an air inlet communicating with the confluence portion, and the movement of the valve core within the valve body controls the air flow rate into the pneumatic actuator.

[0017] In addition, the APU bleed valve also includes an exhaust port, which is located downstream of the confluence. Attached Figure Description

[0018] Figure 1 A schematic diagram of the structure of an APU bleed valve in the prior art is shown.

[0019] Figure 2 A schematic diagram of the APU bleed valve according to the present invention is shown, wherein the valve of the bleed valve is in the closed position.

[0020] Figure 3 Another structural schematic diagram of the APU bleed valve according to the present invention is shown, wherein the valve of the bleed valve is in the middle position.

[0021] Figure 4 Another structural schematic diagram of the APU bleed valve according to the present invention is shown, wherein the valve of the bleed valve is in the fully open position.

[0022] List of reference numerals

[0023] 1APU bleed air valve

[0024] 10 air intake shell

[0025] 20 valves

[0026] 30 pneumatic actuator

[0027] 31 Piston

[0028] 33 springs

[0029] 40 Solenoid Valve

[0030] 41 Solenoid valve body

[0031] 42 valve core

[0032] 50 Gas intake bypass

[0033] 51 First Gas Intake Bypass

[0034] 52 Second Gas Intake Bypass

[0035] 53 Air Filter

[0036] 54 Bypass Valve

[0037] 55 Differential Pressure Sensor

[0038] 58 Meeting Point

[0039] 60 air intake port

[0040] 65 Exhaust Port

[0041] 80 position switch

[0042] 85 balance lever Detailed Implementation Plan

[0043] The present invention will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual application situations without departing from the spirit of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.

[0044] Figures 2 to 4 A schematic structure of an APU bleed air valve 1 in an aircraft auxiliary power unit system according to a preferred embodiment of the present invention is shown. The APU bleed air valve 1 mainly includes a bleed air housing 10, a valve 20, a pneumatic actuator 30, and a solenoid valve 40.

[0045] The bleed gas housing 10 is configured to introduce high-pressure gas generated by the APU into the interior of the APU bleed gas valve 1. The valve 20, typically a butterfly valve, is rotatably mounted within the housing 10. The open / closed state of the valve 20 determines whether gas from the APU can enter the downstream gas supply system. Typically, as... Figure 2 As shown, when valve 20 is closed, the bleed air is blocked; as Figure 4 As shown, when valve 20 is open, bleed air enters the air supply system through valve 20 to provide the necessary air supply support for the aircraft. Valve 20 is designed to have good sealing and durability to withstand high-pressure and frequent operation environments.

[0046] In the APU bleed valve 1, the pneumatic actuator 30 is the actuator that drives the valve 20 to open and close. The pneumatic actuator 30 is connected to the valve 20 via a shaft. Figure 2 Schematic representation: The pneumatic actuator 30 mainly includes a piston 31, a cylinder assembly, a diaphragm, and a spring 33. The pneumatic actuator 30 is actuated by high-pressure gas generated by the APU. This high-pressure gas can be obtained through an air intake port 60 located on the housing 10, but the air intake port 60 can also be located at other points in the pipeline through which the high-pressure gas flows, upstream of the valve 20. When high-pressure gas enters the pneumatic actuator 30 from the air intake port 60, the gas pressure pushes the piston 31 in a reciprocating motion, thereby rotating the shaft, which in turn drives the valve 20 to open and close. The spring 33 in the pneumatic actuator 30 is configured to push the piston 31 back to its original position when the gas pressure is insufficient, ensuring that the valve 20 can automatically close and ensuring system safety.

[0047] As described above, the high-pressure gas used to actuate the pneumatic actuator 30 comes from the gas intake port 60. The gas intake port 60 is connected to the air inlet port of the pneumatic actuator 30 through the gas intake bypass 50. The solenoid valve 40 in the APU bleed valve 1 is installed in the gas intake bypass 50, located downstream of the confluence 58 of the first gas intake bypass 51 and the second gas intake bypass 52, and is used to regulate the gas flow rate entering the pneumatic port of the pneumatic actuator 30 through the gas intake bypass 50.

[0048] Specifically, the solenoid valve 40 includes a valve core 42 movable within a solenoid valve body 41, and also has an exhaust port 65 for discharging gas. For example... Figure 2 As shown, when the solenoid valve 40 is not energized, the valve core 42 is in the first closed position, the gas flow path from the gas intake port 60 to the pneumatic actuator 30 is cut off, while the gas intake bypass 50 from the gas intake port 60 to the pneumatic actuator 30 remains unobstructed. At this time, the valve 20 will be in the closed state. Figure 3As shown, when the solenoid valve 40 is actuated, causing the valve core 42 to move to the second intermediate position, the gas flow path from the gas intake port 60 to the pneumatic actuator 30 opens. A portion of the high-pressure gas flow from the APU flows into the pneumatic actuator 30, while the other portion is discharged through the exhaust port 65. At this time, the valve 20 is in a partially open state. Figure 4 As shown, when the solenoid valve 40 is actuated to move the valve core 42 further to the third open position, the gas intake bypass 50 from the gas intake port 60 to the pneumatic actuator 30 is opened, the airflow path between the exhaust port 65 and the pneumatic actuator 30 is cut off, and all the high-pressure gas flow from the APU flows into the pneumatic actuator 30, causing the valve 20 to enter the fully open state.

[0049] In particular, in the preferred embodiment according to this utility model, such as Figure 2-4 As shown, the intake bypass 50 provides an airflow path from the intake port 60 to the intake port of the pneumatic actuator 30. The intake bypass 50 includes a first intake bypass 51 and a second intake bypass 52, which are connected in parallel between the intake port 60 and the pneumatic actuator 30.

[0050] An air filter 53 is provided in the first air intake bypass 51, and a bypass valve 54 is provided in the second air intake bypass 52. The air filter 53 is configured to filter the airflow entering the pneumatic actuator 30 from the air intake port 60, while the bypass valve 54 is configured to open when the air filter 53 fails, providing an emergency airflow path from the air intake port 60 to the pneumatic actuator 30. Specifically, when the air filter 53 is working normally and filtering the airflow from the air intake port 60, the bypass valve 54 is closed, so all the airflow from the air intake port 60 passes through the air filter 53 before flowing into the downstream pneumatic actuator 30. When the air filter 53 fails, the bypass valve 54 will open, guiding the airflow from the air intake port 60 through the bypass valve 54 to bypass the filter 53 and flow to the downstream pneumatic actuator 30.

[0051] An air filter 53 is installed in the air intake bypass 50 to filter the airflow to the pneumatic actuator 30, effectively preventing the downstream solenoid valve 40 and the pneumatic actuator 30 from being affected by pollutants or impurities in the airflow, which may cause them to jam or even fail, thus ensuring the reliability of the APU operation.

[0052] In order to ensure that the bypass valve 54 can open in time when the air filter 53 fails, the APU bleed valve 1 is also equipped with an air filter detection device for detecting whether the air filter 53 has failed.

[0053] Preferably, the air filter detection device includes a differential pressure sensor 55, which is arranged to detect the pressure difference between the upstream and downstream of the air filter 53. Typically, the differential pressure sensor 55 includes two pressure ports (a high-pressure port and a low-pressure port), connected upstream and downstream of the air filter 53, respectively. Internally, the sensor measures the pressure difference between the two ports using a diaphragm, piezoresistive element, or other sensing technology, and converts it into an electrical signal output. When the pressure difference detected by the differential pressure sensor 55 between the high-pressure port and the low-pressure port exceeds a preset value, the bypass valve 54 is opened. Simultaneously, the signal from the differential pressure sensor 55 is communicated to the control device to issue a warning signal. Upon receiving the warning signal, maintenance personnel replace the air filter 53 to ensure normal filtration function.

[0054] To accurately determine the status of the air filter 53, a pressure difference threshold can be preset. When the air filter 53 is working normally, the first pressure difference detected by the differential pressure sensor 55 is normally less than the preset pressure difference threshold. When the air filter 53 is clogged by impurities in the airflow, the differential pressure sensor 55 will detect a second pressure difference, which will be greater than the preset pressure difference threshold. When the differential pressure sensor 55 detects a second pressure difference exceeding the pressure difference threshold, the control system will determine that the air filter 53 has failed and cannot filter the airflow normally. To prevent the operation of the downstream pneumatic actuator 30 from being affected, the bypass valve 54 is opened, allowing the airflow from the air intake port 60 to bypass the air filter 53 and enter the pneumatic actuator 30 via the control of the solenoid valve 40.

[0055] In some cases, the air filter 53 may also be damaged, in which case the pressure difference across the air filter 53 will decrease. An appropriate additional threshold can be set, and this situation can be detected using the differential pressure sensor 55.

[0056] On the other hand, in a preferred embodiment according to the present invention, such as Figure 1 As shown, the APU bleed valve 1 includes a position switch 80. The position switch has two trigger parts: a fully open trigger part indicating that the valve is fully open and a fully closed trigger part indicating that the valve is fully closed. In other words, when the valve 20 is moved to the position indicated by the position switch 80, the valve will automatically close. Figure 4 When the valve 20 is positioned parallel to the extension direction of the bleed air housing 10, the fully open trigger will be activated to issue an indication signal, indicating that the valve 20 has rotated to the fully open position and the air flow rate in the passage provided by the bleed air housing 10 is at its maximum; when the valve 20 rotates with the shaft to the position shown, the fully open trigger will be activated to issue an indication signal, indicating that the valve 20 has rotated to the fully open position and the air flow rate in the passage provided by the bleed air housing 10 is at its maximum. Figure 1 When the air bleed housing 10 is in the position where the pipeline is completely closed, the fully closed trigger will be activated to generate a shutdown indication signal. Thus, the position switch according to this invention can detect not only the fully closed state of the valve but also the fully open state, thereby identifying when the APU air bleed valve 1 is stuck in the half-open position. Figure 3 As shown, the APU bleed air valve is stuck in the half-open position. In some applications, valve 20 being in the half-open position can cause insufficient downstream air volume, which can lead to poor performance or limited operation of some systems or equipment, such as difficulty or failure to start the engine, degraded performance of the air conditioning system, and increased load on the power system.

[0057] In a preferred embodiment, the two triggering parts of the position switch 80 can be triggered by a swing arm mounted on a shaft and swinging with the shaft. As shown, one end of the swing arm 85 is mounted on the shaft, the swing arm extends radially outward, and the free end extends to a position where it can contact the triggering part, thereby triggering the corresponding position indication signal through direct contact.

[0058] In other alternative embodiments, the position switch indicating the fully open state of the valve can also employ two non-contact switching units to monitor the position. For example, photoelectric or magnetic induction switching units can be used, where a specific component mounted on the shaft and rotating with the shaft non-contactly triggers the corresponding position induction switch to provide a position indication signal. The non-contact design reduces wear and is suitable for high-durability applications.

[0059] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible variations and modifications without departing from the spirit and scope of the present invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. An APU bleed air valve, comprising: A housing, wherein the housing is provided with an air intake port; A valve, which is rotatably disposed within a housing; A pneumatic actuator is connected to a valve via a shaft, and the pneumatic actuator is connected to a gas intake port via a gas intake bypass, and the pneumatic actuator is configured to cause the shaft to reciprocate under the action of gas from the gas intake port. A solenoid valve configured to control the direction of airflow entering the pneumatic actuator from the air intake port; The gas intake bypass connecting the gas intake port to the pneumatic actuator includes a first gas intake bypass and a second gas intake bypass, wherein the first gas intake bypass and the second gas intake bypass are connected in parallel between the gas intake port and the pneumatic actuator. The APU bleed air valve also includes: An air filter is provided in the first gas intake bypass; A flow control valve is provided downstream of the air intake port, the flow control valve being arranged to open the second air intake bypass when the air filter fails; and An air filter detection device is used to detect whether the air filter is malfunctioning.

2. The APU bleed valve as described in claim 1, characterized in that, The flow control valve includes a bypass valve disposed in the second air intake bypass, the bypass valve being connected in parallel with the air filter, the inlet of the bypass valve being connected to the air intake port, and the outlet of the bypass valve being connected to the pneumatic actuator.

3. The APU bleed valve as described in claim 1, characterized in that, The air filter detection device includes a differential pressure sensor, which has a high-pressure port and a low-pressure port, respectively connected to the upstream and downstream positions of the air filter to detect the pressure difference between the upstream and downstream of the air filter. When the pressure difference detected by the differential pressure sensor exceeds a preset differential pressure threshold, the bypass valve in the second air intake bypass is opened.

4. The APU bleed valve as described in claim 1, characterized in that, The APU bleed valve also includes a position switch configured to indicate the fully open position and the fully closed position of the valve, respectively.

5. The APU bleed valve as described in claim 4, characterized in that, The position switch includes a fully open trigger that indicates the valve is fully open and a fully closed trigger that indicates the valve is fully closed. The shaft is equipped with a swing arm that is fixed to the shaft and rotates with the shaft. When the shaft drives the valve to the fully open position, the swing arm triggers the fully open trigger unit; When the shaft drives the valve to rotate to the fully closed position, the swing arm triggers the fully closed trigger unit.

6. The APU bleed valve as described in claim 4, characterized in that, The position switch includes a non-contact first sensor switch and a second sensor switch. When the valve is rotated to the fully open position, the first sensor switch is triggered, and when the valve is rotated to the fully closed position, the second sensor switch is triggered.

7. The APU bleed valve as described in claim 1, characterized in that, The solenoid valve is located downstream of the confluence of the first and second gas intake bypasses and upstream of the pneumatic actuator.

8. The APU bleed valve as described in claim 7, characterized in that, The solenoid valve has a valve core and a valve body. The valve body is provided with an air inlet that communicates with the confluence. The movement of the valve core within the valve body controls the air flow rate into the pneumatic actuator.

9. The APU bleed valve as described in claim 7, characterized in that, The APU bleed valve also includes an exhaust port, which is located downstream of the confluence.

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