Auxiliary tool for oil pan discharge of main oil tank of Boeing B737NG aircraft

Abstract

An auxiliary tool for oil bottom discharge of a main oil tank of a Boeing B737NG airplane relates to the technical field of airplane maintenance tools, a lift valve is driven by a lift valve driving mechanism to slide upwards in a containing cavity of an oil discharge pipe by utilizing a piston, a valve core of a water discharge valve is gradually opened when the lift valve moves upwards, fuel oil is discharged from the water discharge valve, and the oil bottom discharge of the main oil tank of the Boeing B737NG airplane is realized. Due to the fact that the piston isolates the long hole I from the long hole II, fuel oil enters the oil storage cavity of the lifting valve from the long hole I, then flows out from the long hole II and finally flows into an oil barrel to be stored through the connecting pipe and the hose. A worker does not need to use an oil drainage rod to always prop the water drainage valve in the oil drainage process, the oil drainage efficiency is improved, and manpower is saved.

Description

Technical Field

[0001] This utility model relates to the field of aircraft maintenance tool technology, specifically to an auxiliary tooling for draining oil from the main fuel tank bottom of a Boeing B737NG aircraft. Background Technology

[0002] The main fuel tanks of the Boeing B737NG aircraft are located on both sides of the wings, and their function is to store the fuel required for flight. Because the wings have an anhedral angle (i.e., the wings are tilted upwards at approximately 7 degrees), a safety reserve of fuel is maintained for each flight (approximately 2-4 tons more fuel than normal for emergency use). However, water inevitably mixes into the fuel during production, and water is denser than fuel. Therefore, water accumulates at the base of the wing fuel tanks. This accumulation of water, combined with the organic nutrients in the fuel, can breed microorganisms. Microbial contamination can cause fuel line blockages, and their excrement can corrode the aircraft structure, endangering flight safety. Therefore, Boeing has installed drain valves at the base of the wing fuel tanks. Before each flight, maintenance personnel operate these drain valves to drain a certain amount of fuel (approximately 1-2 liters) to prevent long-term water accumulation. However, during a major aircraft overhaul, the fuel in the tanks needs to be emptied to allow for internal inspection. Boeing only provides instructions on draining fuel through the drain valves in the maintenance manual. This method of draining oil (generally referred to as oil pan) is extremely inefficient and incurs enormous time and labor costs.

[0003] B737NG Aircraft Main Fuel Tank Draining Method: 1) Clean the drain rod, drain valve, and surrounding skin; 2) Approach the main fuel tank drain valve as required; 3) Place the fuel can under the drain valve, insert the end of the drain rod into the can, and align the top of the drain rod with the top lift valve of the drain valve; 4) Push the drain rod upwards to open the drain valve, draining approximately 2 liters of fuel to check for leakage; 5) Ensure the drain valve is reset, wipe the area around the drain valve clean with a cloth, and confirm there is no fuel leakage. Based on the entire draining process, this method requires personnel to keep the drain valve in the raised position using the drain rod, resulting in a relatively small flow rate, making it unsuitable for draining large amounts of fuel from the tank. Summary of the Invention

[0004] In order to overcome the shortcomings of the above technologies, this utility model provides an auxiliary tooling for quickly emptying the fuel in the main fuel tank of an aircraft using a drain valve.

[0005] The technical solution adopted by this utility model to overcome its technical problem is:

[0006] An auxiliary tooling for draining oil from the main fuel tank plenum of a Boeing B737NG aircraft, comprising:

[0007] The oil drain pipe is open at both ends and has a sealed cavity inside. The upper end of the oil drain pipe is provided with external thread I, which is screwed into the screw hole at the drain valve on the wing skin of the Boeing B737NG aircraft.

[0008] The lift valve has a cylindrical structure, is sealed on all sides, and has a sealed oil storage chamber inside;

[0009] The piston is mounted on the lift valve. The lift valve is slidably mounted in the cavity of the oil drain pipe in the vertical direction through the piston. The lift valve at the upper end of the piston is provided with an elongated hole I that communicates with the cavity, and the lift valve at the lower end of the piston is provided with an elongated hole II that communicates with the cavity.

[0010] The connecting pipe has an external thread Ⅲ at its upper end and a screw hole Ⅰ at its lower end. The connecting pipe is screwed into the screw hole Ⅰ through the external thread Ⅲ, and the lower end of the connecting pipe is connected to the oil drum through a hose.

[0011] The lift valve drive mechanism is located on the drain pipe and is used to control the lift valve to move up and down. When the lift valve moves up to the top, it will open the valve core of the drain valve.

[0012] To improve sealing, a sealing ring I is installed at the connection between the oil drain pipe and the wing skin.

[0013] To improve sealing, a sealing ring II is installed at the connection between the connecting pipe and the drain pipe.

[0014] For easy connection, it also includes a groove on the connecting pipe and a sleeve fitted on the connecting pipe. The screw passes through the sleeve and is inserted into the groove. The sleeve has a groove along the circumferential direction. The upper end of the hose is inserted into the sleeve, and the hose clamp locks the hose in the groove. The lower end of the hose is inserted into the oil drum.

[0015] Furthermore, the aforementioned lift valve drive mechanism includes a branch pipe inclined downward on the oil drain pipe, a pipe joint, a slide rod inserted axially into the pipe joint, and a knob. The head end of the slide rod contacts the lower end face of the lift valve. The upper end of the pipe joint is provided with an external thread IV, and the pipe joint is threadedly connected to the branch pipe through the external thread IV. The lower end of the pipe joint is provided with an external thread II. The knob is provided with a screw hole II, and the knob is screwed onto the external thread II through the screw hole II. The tail end of the slide rod is coaxially rotatably connected to the knob through a rotating connection mechanism. A spring is fitted onto the lift valve, with its upper end connected to the inner wall of the oil drain pipe and its lower end connected to the piston.

[0016] Preferably, the angle between the axis of the branch pipe and the axis of the oil drain pipe is 45°.

[0017] To improve service life, a ball head is also included at the end of the slide rod, which contacts the lower end face of the lift valve.

[0018] To improve sealing, a sealing ring IV is installed at the connection between the slide rod and the pipe joint.

[0019] To improve sealing, a sealing ring III is installed at the connection between the pipe fitting and the branch pipe.

[0020] Furthermore, the aforementioned rotating connection mechanism includes a mounting groove disposed at the knob head end, the mounting groove being connected to the screw hole II via a through hole, a plug disposed at the tail end of the slide rod, the plug passing through the through hole, a washer disposed in the mounting groove, the washer being fitted onto the plug within the mounting groove, and a nut disposed in the mounting groove, the nut being screwed onto the plug within the mounting groove.

[0021] The beneficial effects of this invention are as follows: The lifting valve is driven by a lifting valve drive mechanism, which allows the piston to slide upwards within the cavity of the drain pipe. As the lifting valve moves upwards, it gradually opens the valve core of the drain valve, allowing fuel to drain out. Because the piston isolates long hole I from long hole II, the fuel enters the oil storage chamber of the lifting valve through long hole I, then flows out through long hole II, and finally flows into the oil drum for storage via the connecting pipe and hose. This eliminates the need for operators to continuously push the drain valve with a drain rod during the draining process, improving draining efficiency and saving manpower. Attached Figure Description

[0022] Figure 1 This is a diagram showing the usage state of this utility model;

[0023] Figure 2 This is a cross-sectional structural diagram of the present invention;

[0024] Figure 3 This is a cross-sectional structural diagram of the present invention in the oil discharge state;

[0025] Figure 4 This is a cross-sectional structural diagram of the branch pipe portion of this utility model;

[0026] In the diagram: 1. Oil drum; 2. Large wing skin; 3. Drain valve; 4. Oil drain pipe; 5. Branch pipe; 6. Pipe clamp; 7. Knob; 8. Hose; 9. External thread I; 10. Sealing ring I; 11. Lifting valve; 12. Piston; 13. Spring; 14. Long hole I; 15. Long hole II; 16. Pipe fitting; 17. Slide rod; 18. Ball head; 19. External thread II; 20. Screw hole I; 21. Connecting pipe; 22. External thread III; 23. Sealing ring II; 24. Sleeve; 25. Slot; 26. Groove; 27. Screw; 28. External thread IV; 29. ​​Sealing ring III; 30. Sealing ring IV; 31. Screw hole II; 32. Through hole; 33. Plug; 34. Washer; 35. Nut. Detailed Implementation

[0027] The following is in conjunction with the appendix Figure 1 To be continued Figure 4 The present invention will be further described below.

[0028] An auxiliary tooling for draining fuel from the main fuel tank of a Boeing B737NG aircraft includes: a drain pipe 4, which is open at both ends and has a sealed cavity inside. The upper end of the drain pipe 4 is provided with an external thread I 9. The drain pipe 4 is screwed into the threaded hole at the drain valve 3 on the wing skin 2 of the Boeing B737NG aircraft through the external thread I 9.

[0029] The lifting valve 11 has a cylindrical structure and is sealed on all sides, with a sealed oil storage chamber inside. The piston 12 is installed on the lifting valve 11, and the lifting valve 11 is slidably installed in the cavity of the oil drain pipe 4 in the vertical direction through the piston 12. The lifting valve 11 at the upper end of the piston 12 is provided with an elongated hole I 14 communicating with the cavity, and the lifting valve 11 at the lower end of the piston 12 is provided with an elongated hole II 15 communicating with the cavity. The connecting pipe 21 is provided with an external thread III 22 at its upper end and a threaded hole I 20 at the lower end of the oil drain pipe 4. The connecting pipe 21 is screwed into the threaded hole I 20 through the external thread III 22, and the lower end of the connecting pipe 21 is connected to the oil tank 1 through a hose 8. The lifting valve drive mechanism is provided on the oil drain pipe 4 and is used to control the up and down movement of the lifting valve 11. When the lifting valve 11 moves to the uppermost position, it pushes open the valve core of the drain valve 3. When the aircraft needs to be re-inspected and the fuel tank needs to be emptied, the drain pipe 4 is installed at the drain valve 3 on the wing skin 2. Then, the lift valve 11 is driven by the lift valve drive mechanism to slide upward in the cavity of the drain pipe 4 using the piston 12. As the lift valve 11 moves upward, it gradually opens the valve core of the drain valve 3, and the fuel is discharged from the drain valve 3. Since the piston 12 isolates the long hole I 14 from the long hole II 15, the fuel enters the fuel storage chamber of the lift valve 11 from the long hole I 14, and then flows out from the long hole II 15, finally flowing into the fuel tank 1 for storage through the connecting pipe 21 and the hose 8. This eliminates the need for personnel to use a drain rod to continuously push the drain valve 3 during the fuel draining process, improving fuel draining efficiency and saving manpower.

[0030] In one embodiment of this utility model, a sealing ring I 10 is provided at the connection between the oil drain pipe 4 and the large wing skin 2. A sealing ring II 23 is provided at the connection between the connecting pipe 21 and the oil drain pipe 4. The sealing ring I 10 can improve the sealing performance at the connection between the oil drain pipe 4 and the drain valve 3, and the sealing ring II 23 can improve the sealing performance at the connection between the connecting pipe 21 and the oil drain pipe 4, thus preventing oil leakage.

[0031] In one embodiment of this utility model, it further includes a groove 26 provided on the connecting pipe 21 and a sleeve 24 fitted onto the connecting pipe 21. A screw 27 passes through the sleeve 24 and is inserted into the groove 26. A retaining groove 25 is provided on the sleeve 24 along the circumferential direction. The upper end of the hose 8 is inserted into the sleeve 24, and a pipe clamp 6 locks the hose 8 securely in the retaining groove 25. The lower end of the hose 8 is inserted into the oil drum 1. By fixing the sleeve 24 to the outer end of the connecting pipe 21, and then using the pipe clamp 6 provided in the retaining groove 25 to firmly fix the hose 8 to the sleeve 24, the reliability of use is improved.

[0032] In one embodiment of this utility model, the lifting valve drive mechanism includes a branch pipe 5 inclined downward on the oil drain pipe 4, a pipe joint 16, a slide rod 17 axially inserted in the pipe joint 16, and a knob 7. The head end of the slide rod 17 contacts the lower end face of the lifting valve 11. The upper end of the pipe joint 16 is provided with an external thread IV 28, and the pipe joint 16 is threadedly connected to the branch pipe 5 through the external thread IV 28. The lower end of the pipe joint 16 is provided with an external thread II 19. The knob 7 is provided with a screw hole II 31, and the knob 7 is screwed onto the external thread II 19 through the screw hole II 31. The tail end of the slide rod 17 is coaxially rotatably connected to the knob 7 through a rotating connection mechanism. The spring 13 is fitted on the lifting valve 11, with its upper end connected to the inner wall of the oil drain pipe 4 and its lower end connected to the piston 12. When knob 7 is rotated, it moves axially along the external thread II 19. Since slide rod 17 is rotatably connected to knob 7 via a rotating connection mechanism, slide rod 17 follows knob 7 along the axis of branch pipe 5. Because slide rod 17 is in contact with the bottom of lift valve 11, when slide rod 17 moves obliquely upwards, it pushes lift valve 11 upwards and compresses spring 13, causing lift valve 11 to open the valve core of drain valve 3. When slide rod 17 moves obliquely downwards, spring 13 releases energy to drive lift valve 11 downwards, achieving a reset, and drain valve 3 closes.

[0033] In this embodiment, preferably, the angle between the axis of the branch pipe 5 and the axis of the oil drain pipe 4 is 45°.

[0034] In this embodiment, a ball head 18 may also be provided at the head end of the slide rod 17, and the ball head 18 contacts the lower end face of the lift valve 11. Since the ball head 18 has a smooth spherical surface, when the slide rod 17 moves, the ball head 18 slides and rubs against the lower end face of the lift valve 11, reducing friction, preventing excessive wear of the lift valve 11, and improving its service life.

[0035] In this embodiment, a sealing ring IV 30 is provided at the connection between the slide rod 17 and the pipe joint 16. A sealing ring III 29 is provided at the connection between the pipe joint 16 and the branch pipe 5. By providing the sealing ring IV 30, the sealing performance between the slide rod 17 and the pipe joint 16 can be improved. By providing the sealing ring III 29, the sealing performance between the pipe joint 16 and the branch pipe 5 can be improved, preventing oil leakage.

[0036] In one embodiment of this utility model, the rotating connection mechanism includes a mounting groove disposed at the head end of the knob 7. The mounting groove is connected to the screw hole II 31 through a through hole 32. A plug 33 is disposed at the tail end of the slide rod 17, passing through the through hole 32. A washer 34 is disposed in the mounting groove and fitted onto the plug 33 within the mounting groove. A nut 35 is disposed in the mounting groove and screwed onto the plug 33 within the mounting groove. The slide rod 17 rotates relative to the knob 7 through the plug 33. Axial limiting is achieved by the washer 34 and the nut 35 disposed in the mounting groove, so that when the knob 7 is rotated, the slide rod 17 does not rotate relative to the knob 7, but moves axially along with the knob 7.

[0037] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An auxiliary tooling for draining oil from the main fuel tank plenum of a Boeing B737NG aircraft, characterized in that, include: The oil drain pipe (4) has openings at both ends and a sealed cavity inside. The upper end of the oil drain pipe (4) is provided with an external thread I (9). The oil drain pipe (4) is screwed into the screw hole at the drain valve (3) on the wing skin (2) of the Boeing B737NG aircraft through the external thread I (9). The lift valve (11) has a cylindrical structure. The lift valve (11) is sealed on all sides and has a sealed oil storage chamber inside. Piston (12) is mounted on lift valve (11). Lift valve (11) is slidably mounted in the cavity of oil drain pipe (4) in the vertical direction via piston (12). The lift valve (11) located at the upper end of piston (12) is provided with an elongated hole I (14) communicating with the cavity. The lift valve (11) located at the lower end of piston (12) is provided with an elongated hole II (15) communicating with the cavity. The connecting pipe (21) has an external thread Ⅲ (22) at its upper end, and the oil drain pipe (4) has a screw hole Ⅰ (20) at its lower end. The connecting pipe (21) is screwed into the screw hole Ⅰ (20) through the external thread Ⅲ (22), and the lower end of the connecting pipe (21) is connected to the oil drum (1) through the hose (8). The lifting valve drive mechanism is located on the drain pipe (4) and is used to control the lifting valve (11) to move up and down. When the lifting valve (11) moves up to the top, it will open the valve core of the drain valve (3).

2. The auxiliary tooling for draining oil from the main fuel tank of a Boeing B737NG aircraft according to claim 1, characterized in that: A sealing ring I (10) is provided at the connection between the oil drain pipe (4) and the large wing skin (2).

3. The auxiliary tooling for draining oil from the main fuel tank of a Boeing B737NG aircraft according to claim 1, characterized in that: A sealing ring II (23) is provided at the connection between the connecting pipe (21) and the drain pipe (4).

4. The auxiliary tooling for draining oil from the main fuel tank of a Boeing B737NG aircraft according to claim 1, characterized in that: It also includes a groove (26) set on the connecting pipe (21) and a sleeve (24) fitted on the connecting pipe (21). The screw (27) passes through the sleeve (24) and is inserted into the groove (26). The sleeve (24) is provided with a groove (25) along the circumferential direction. The upper end of the hose (8) is inserted into the sleeve (24). The pipe clamp (6) locks the hose (8) in the groove (25). The lower end of the hose (8) is inserted into the oil drum (1).

5. The auxiliary tooling for draining oil from the main fuel tank of a Boeing B737NG aircraft according to claim 1, characterized in that: The lifting valve drive mechanism includes a branch pipe (5) inclined downward on the oil drain pipe (4), a pipe joint (16), a slide rod (17) inserted axially in the pipe joint (16), and a knob (7). The head end of the slide rod (17) is in contact with the lower end face of the lifting valve (11). The upper end of the pipe joint (16) is provided with an external thread IV (28). The pipe joint (16) is threaded to the branch pipe (5) through the external thread IV (28). The lower end of the pipe joint (16) is provided with an external thread II (19). The knob (7) is provided with a screw hole II (31). The knob (7) is screwed onto the external thread II (19) through the screw hole II (31). The tail end of the slide rod (17) is coaxially rotatably connected to the knob (7) through a rotating connection mechanism. The spring (13) is fitted on the lifting valve (11). Its upper end is connected to the inner wall of the oil drain pipe (4), and its lower end is connected to the piston (12).

6. The auxiliary tooling for draining oil from the main fuel tank of a Boeing B737NG aircraft according to claim 5, characterized in that: The angle between the axis of the branch pipe (5) and the axis of the oil drain pipe (4) is 45°.

7. The auxiliary tooling for draining oil from the main fuel tank of a Boeing B737NG aircraft according to claim 5, characterized in that: It also includes a ball head (18) disposed at the head end of the slide bar (17), the ball head (18) being in contact with the lower end face of the lift valve (11).

8. The auxiliary tooling for draining oil from the main fuel tank of a Boeing B737NG aircraft according to claim 5, characterized in that: A sealing ring IV (30) is provided at the connection between the slide rod (17) and the pipe joint (16).

9. The auxiliary tooling for draining oil from the main fuel tank of a Boeing B737NG aircraft according to claim 5, characterized in that: A sealing ring Ⅲ (29) is provided at the connection between the pipe fitting (16) and the branch pipe (5).

10. The auxiliary tooling for draining oil from the main fuel tank of a Boeing B737NG aircraft according to claim 5, characterized in that: The rotating connection mechanism includes a mounting groove at the head end of the knob (7), which is connected to the screw hole II (31) through a through hole (32). The tail end of the slide rod (17) is provided with a plug (33), which passes through the through hole (32). A washer (34) is provided in the mounting groove and is fitted onto the plug (33) in the mounting groove. A nut (35) is provided in the mounting groove and is screwed onto the plug (33) in the mounting groove.

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