Air-tight clamp for liquid rocket engine and using method of air-tight clamp

Abstract

The invention discloses a liquid rocket engine airtight clamp and a using method thereof. The clamp comprises a handle, a large nut, a jacking hand wheel, a supporting disc, a long pull rod, a short pull rod, a spring, an air inlet pipe, a sealing disc and a turning plate. When the airtight clamp enters the engine, the turning plate is in an inclined state, after the turning plate completely enters the throat part of the engine, the handle is pulled to enable the turning plate to be in a state perpendicular to the axis of the engine, and the turning plate is clamped above the throat part of the engine; then the large nut is rotated, the sealing disc moves towards the throat of the engine until the large nut cannot rotate, at the moment, the turning plate and the throat sealing ring on the sealing disc clamp the engine, meanwhile, the supporting disc is attached to the large end of the engine under the action of the spring, and the airtight clamp is fixed to the engine. An external air source is connected with the air inlet pipe to inflate the inner cavity of the engine. The airtight test clamp can be widely applied to the field of sealing of small rocket engines, and has the advantages of being novel in structure, reliable in sealing and easy to operate.

Description

Technical Field

[0001] The present invention relates to an airtight fixture for a liquid rocket engine and its usage method, which is applied to the airtight test of liquid rocket engines, especially the airtight test of small engines, and belongs to the field of test technology. Background Art

[0002] Liquid rocket engines are characterized by high precision and high risk. During operation, they bear extremely high pressure and temperature inside, and any leakage may lead to catastrophic consequences. Conducting an airtight test on the engine can identify and eliminate potential sealing hazards in advance, effectively reduce the accident risk during engine operation, and ensure the safety of personnel's lives and property.

[0003] Good airtightness is the basis for ensuring the normal operation of rocket engines. The airtight test can accurately detect potential tiny leakage channels, prevent the leakage of fuel or oxidizer under high pressure, and ensure reliable power output of the engine; through the airtight test, the manufacturing process and component quality of the engine can also be strictly inspected, and defects in the manufacturing process, such as loose welding, improper installation of seals, assembly deviation, etc., can be found in time, thereby improving the overall quality and reliability of the engine. Currently, there is no information on airtight test fixtures for liquid rocket engines. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: to overcome the deficiencies of the prior art and provide an airtight fixture for a liquid rocket engine and its usage method.

[0005] The technical solution of the present invention is:

[0006] An airtight fixture for a liquid rocket engine includes a handle, a large nut, a tightening handwheel, a support disk, a long pull rod, a short pull rod, a spring, a backup tightening nut, an air inlet pipe, a sealing disk, and a flap.

[0007] A first sealing ring and a tightening nut are installed on the outer side of the air inlet pipe, and the tightening nut is located below the first sealing ring. A first pin shaft is installed at the upper end of the air inlet pipe, and one end of the short pull rod is connected to the first pin shaft. The above structure forms a central component; the above central component passes through the central through hole of the long pull rod, and the two form a sandwich component. The lower end of the long pull rod is tightened by the backup tightening nut and the large nut, and the short pull rod is fixed in the rectangular groove at the upper end of the long pull rod; the support disk, the spring, and the tightening handwheel 3 sequentially pass through the sealing disk, and the tightening handwheel is fixed on the sealing disk with a set screw to form an outer component, and a through hole is provided in the center of the outer component.

[0008] The sandwich component is sleeved in the through hole of the outer component. The large nut is threadedly connected to the inner wall surface at the lower end of the sealing disc. The set screw passes through the sealing disc and is stuck in the limit groove of the long pull rod. A first sealing ring is arranged at the contact position between the upper end of the sealing disc and the long pull rod. The throat sealing ring is installed outside the upper end of the sealing disc.

[0009] The flap is of a fan-shaped structure with a rectangular hole machined inside. The upper parts of the long pull rod and the short pull rod are both inserted into the rectangular hole, and the long pull rod is fixedly connected to the flap through a third pin shaft, and the short pull rod is fixedly connected to the flap through a second pin shaft.

[0010] The handle is fixed to the air inlet nozzle of the air inlet pipe through a set screw, and the air inlet pipe is moved up and down by pushing and pulling the handle.

[0011] Preferably, the air inlet pipe includes an inner fork, a long connecting pipe, a short connecting pipe, an air inlet nozzle, and a tightening nut.

[0012] The inner fork, the long connecting pipe, and the short connecting pipe are welded in sequence. One end of the air inlet nozzle is welded to the short connecting pipe, and the other end is provided with a flared joint for connecting to an external air source. The short connecting pipe is provided with a flange, and a sealing groove is arranged on the flange for installing a first sealing ring. The tightening nut is installed on the short connecting pipe and is located below the flange.

[0013] A first pin shaft is arranged at the upper end of the inner fork. A rectangular groove with a certain length is arranged in the middle of the inner fork for installing the short pull rod. A flange with a certain length is arranged outside the inner fork for forming a clearance fit with the inner hole at the upper end of the long pull rod to play a guiding role when the air inlet pipe moves up and down. The handle is fixed to the air inlet nozzle of the air inlet pipe through a set screw. A through hole is opened in the center of the air inlet pipe for introducing gas into the engine during the airtightness test.

[0014] Preferably, the long pull rod is welded by an outer fork, a guiding pipe, and a joint in sequence. A rectangular groove with a certain length is arranged at the front end of the outer fork, and the short pull rod is installed in the rectangular groove. The outer fork is connected to the flap through a second pin shaft. A plane with a certain length is arranged on the outer cylindrical surface of the outer fork for passing through the flap. A limit groove is opened on the outer wall of the guiding pipe, and the fastening screw passes through the sealing disc and is stuck in the limit groove. When the large nut rotates, it can limit the long pull rod to move only up and down along the engine axis without rotating. The outside of the joint is connected to the large nut through a backup nut. The inside of the joint forms a seal with the air inlet pipe and the first sealing ring. An internal thread is arranged in the inner hole of the joint for fixedly connecting with the tightening nut to prevent the air inlet pipe from slipping out of the long pull rod during the airtightness process.

[0015] Preferably, both the left and right ends of the large nut are of internal thread structures. One end is connected to the sealing disc, and the other end connects the large nut and the long pull rod together through a backup nut. By rotating the large nut, the long pull rod can drive the flap to move up and down along the engine axis.

[0016] Preferably, one end of the short pull rod is connected to the inner fork of the intake pipe through the first pin shaft, and the other end is connected to the flap through the second pin shaft. The flap can be rotated by a certain angle around the center by pushing and pulling the handle.

[0017] Preferably, the sealing disc is sequentially welded by a disc body, a cylinder, and an adjusting cylinder; a plurality of holes with equal sizes are evenly distributed on the cylinder to reduce the weight of the airtight fixture; a set screw is installed on the cylinder, and the set screw is stuck in the limit groove on the guide pipe; the outer side of the adjusting cylinder is a trapezoidal thread and is connected to the large nut; a sealing groove is provided in the inner hole of the disc body for installing the second sealing ring; a profiling groove is provided on the outer side of the disc body for installing the throat sealing ring to achieve the seal between the airtight fixture and the inner wall of the engine.

[0018] Preferably, the throat sealing ring has a certain compressibility, and the cross-sectional diameter is greater than 20 mm.

[0019] Preferably, the materials of the jacking handwheel and the support disc are both aluminum.

[0020] Preferably, the spring is a cylindrical compression spring and is installed between the jacking handwheel and the support disc to press the support disc against the large end face of the engine.

[0021] Preferably, a guide hole is opened in the center of the support disc and passes through the cylinder of the sealing disc. When the large nut is rotated, the jacking handwheel moves upward along with the sealing disc, and the support disc is closely attached to the large end of the engine through the spring, thereby restricting the swing of the airtight fixture.

[0022] Preferably, four observation holes are evenly distributed on the support disc to observe the position of the airtight fixture inside the engine and check whether there is leakage of the airtight fixture during the airtight process.

[0023] Preferably, the flap is in a fan shape, and the outer diameter of the outer circle is greater than the diameter of the engine throat, so that the flap can be stuck above the engine throat; a chamfer is provided on the outer periphery of the flap for fitting with the inner wall of the engine; both sides of the flap are flat surfaces, so that the flap can enter the engine throat when tilted; a rectangular groove is provided in the middle of the flap for the outer fork and the short pull rod to pass through; two groups of through holes are provided on the flat surfaces on both sides of the flap for installing the second pin shaft and the third pin shaft. One group is on the center line of the flap for connecting with the outer fork through the third pin shaft, and the position of the other group has a certain distance from the center line for connecting with the short pull rod through the second pin shaft.

[0024] A method for using an airtight fixture for a liquid rocket engine includes the following steps:

[0025] S1 Hold the jacking handwheel and rotate the large nut counterclockwise to raise the flap to the highest point;

[0026] S2 Hold the tightening handwheel, push the handle to make the flap in an inclined state until it reaches the maximum position, firmly hold the airtight fixture and slowly place it into the engine throat, making the flap above the throat until the support disc abuts against the large end face of the engine;

[0027] S3 Pull the handle to turn the flap to the "horizontal" state;

[0028] S4 Install the anti-loosening clamp between the handle and the tightening nut to restrict the movement of the handle;

[0029] S5 Pull the handle downward with hand and rotate the large nut clockwise to clamp the engine with the sealing disc and the flap. At this time, the airtight fixture reaches the sealing position;

[0030] S6 Connect the external air source to the inner fork of the intake pipe and inflate the inner cavity of the engine to conduct an airtightness test;

[0031] S7 After the airtightness test is completed, rotate the large nut counterclockwise to raise the flap to the highest point;

[0032] S8 Remove the anti-loosening clamp and push the handle upward to turn the flap to the inclined position;

[0033] S9 Take out the airtight fixture from the engine.

[0034] Preferably, the anti-loosening clamp consists of two half rings and can be opened and closed; after the anti-loosening clamp is opened, it is installed between the handle and the tightening nut of the intake pipe, and is locked after closing to prevent the flap from being unevenly stressed or improperly operated during the airtightness test, causing the flap to become inclined and resulting in the axial movement of the intake pipe, thus causing the airtight fixture to be ejected from the engine.

[0035] The present invention has the following beneficial effects:

[0036] (1) The present invention can realize the airtightness test and on-line leak detection of the liquid rocket engine in the whole machine state, and has the advantages of simple structure, reliable sealing, novel structure and strong adaptability;

[0037] (2) The present invention is relatively light in weight. When the engine is undergoing an airtightness test, it has a certain height and limited space. Using the present invention can achieve the effect of single-person operation;

[0038] (3) The present invention adopts flexible contact at all parts in contact with the engine, effectively avoiding the risk of the airtight fixture knocking and damaging the engine during the airtightness test. Brief Description of the Drawings

[0039] Figure 1 It is an assembly sectional view of the airtight fixture for the liquid rocket engine of the present invention;

[0040] Figure 2Schematic structural diagram of the flap of the present invention in an inclined state.

[0041] Figure 3 Schematic structural diagram of the intake pipe of the present invention;

[0042] Figure 4 Schematic structural diagram of the long pull rod of the present invention;

[0043] Figure 5 Schematic structural diagram of the outer fork on the long pull rod of the present invention;

[0044] Figure 6 Schematic structural diagram of the sealing disc;

[0045] Figure 7 Front view of the flap;

[0046] Figure 8 Cross-sectional view of the flap. Detailed implementation manner

[0047] The present invention will be described in detail below, and the features and advantages of the present invention will become clearer and more distinct with these descriptions.

[0048] The special word "exemplary" here means "serving as an example, embodiment or illustration". Any embodiment described here as "exemplary" does not have to be construed as superior or better than other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings do not have to be drawn to scale unless otherwise specified.

[0049] The present invention solves the problem of airtight test for liquid rocket engines, and provides a liquid rocket engine airtight fixture with novel structure, reliable sealing and simple operation.

[0050] Such as Figure 3As shown, the intake pipe 15 is composed of an inner fork 15-1, a long connecting pipe 15-2, a short connecting pipe 15-3, an intake nozzle 15-4, and a tightening nut 15-5. Except for the tightening nut 15-5, the other parts are welded together. After the intake pipe 15 is installed in the long pull rod 5, it is connected to the joint 5-3 of the long pull rod 5 through the tightening nut 15-5 to prevent the intake pipe 15 from slipping out of the long pull rod 5 during the airtight process. One end of the intake nozzle 15-4 is welded to the short connecting pipe 15-3, and the other end is provided with a 37° flared joint for connecting to an external air source. The long connecting pipe 15-2 is used to adjust the length of the intake pipe 15. The short connecting pipe 15-3 is provided with a flange, and a sealing groove is provided on the flange for installing the small sealing ring 12. The inner fork 15-1 is provided with a rectangular groove of a certain length in the middle for installing the short pull rod 6. The outer side of the inner fork 15-1 is provided with a flange of a certain length for forming a clearance fit with the inner hole of the outer fork 5-1, which plays a guiding role when the intake pipe 15 moves up and down. A through hole is opened in the center of the intake pipe 15 for introducing gas into the engine during the airtight test.

[0051] As Figure 1 shown, the handle 1 is fixed to the intake nozzle 15-4 of the intake pipe 15 by a set screw. By pushing and pulling the handle 1, the intake pipe 15 can be moved up and down.

[0052] As Figure 4 and Figure 5 shown, the long pull rod 5 is welded by an outer fork 5-1, a guide pipe 5-2, and a joint 5-3. The outer fork 5-1 is provided with a rectangular groove of a certain length in the middle, and the short pull rod 6 is installed in the rectangular groove; the outer fork 5-1 is connected to the flap 17 through the third pin 93. The outer circular surface of the rectangular groove of the outer fork 5-1 is provided with a plane of a certain length for passing through the flap 17. A limit groove is opened on the outer wall of the guide pipe 5-2. After the set screw 8 passes through the cylinder 16-2 of the sealing disc 16, it is stuck in the limit groove. When the large nut 2 rotates, the long pull rod 5 can be restricted to move only up and down along the engine axis without rotating. The outer side of the joint 5-3 is connected to the large nut 2 through a backup nut 11; the inner side of the joint 5-3 forms a seal with the intake pipe 15 and the first sealing ring 12; the inner hole of the joint 5-3 is provided with an internal thread for installing the tightening nut 15-5.

[0053] Both ends of the large nut 2 are of internal thread structure. One end is connected to the adjusting cylinder 16-3 of the sealing disc 16, and the other end connects the large nut 2 to the long pull rod 5 through the backup nut 11. By rotating the large nut 2, the long pull rod 5 can drive the flap 17 to move up and down along the engine axis.

[0054] One end of the short pull rod 6 is connected to the inner fork 15-4 of the intake pipe 15 through the first pin 91, and the other end is connected to the flap 17 through the second pin 92. By pushing and pulling the handle 1, the flap 17 can be rotated by a certain angle around the center.

[0055] As Figure 6 shown, the sealing disc 16 is welded by a disc body 16-1, a cylinder 16-2, and an adjusting cylinder 16-3. A plurality of small holes of equal size are evenly distributed on the cylinder 16-2 to reduce the weight of the airtight fixture. A set screw 8 is installed on the cylinder 16-2, and the set screw 8 is stuck in the limit groove on the guide tube 5-2. The outer side of the adjusting cylinder 16-3 is a trapezoidal thread, which is connected to the large nut 2. A sealing groove is provided in the inner hole of the disc body 16-1 for installing the large sealing ring 13; a profiling groove is provided on the outer side of the disc body 16-1 for installing the throat sealing ring 14 to achieve the seal between the airtight fixture and the inner wall of the engine.

[0056] The first sealing ring 12 is installed on the short connecting pipe 15-3 of the intake pipe 15 for sealing between the intake pipe 15 and the long pull rod 5.

[0057] The second sealing ring 13 is installed inside the disc body 16-1 of the sealing disc 16 for sealing between the sealing disc 16 and the long pull rod 5.

[0058] The throat sealing ring 14 is made of special rubber, has a certain compressibility, a cross-sectional diameter greater than 20 mm, and is installed on the outside of the sealing disc 16.

[0059] The tightening handwheel 3 is fixed to the adjusting cylinder 16-3 of the sealing disc 16 by a set screw 8. The material of the tightening handwheel 3 is aluminum, and the purpose is to reduce the weight of the airtight fixture.

[0060] The spring 7 is a cylindrical compression spring, which is installed between the tightening handwheel 3 and the support disc 4 for pressing the support disc 4 against the large end face of the engine.

[0061] A guide hole is opened in the center of the support disc 4 and passes through the cylinder 16-2 of the sealing disc 16. When the large nut 2 is rotated, the tightening handwheel 3 moves upward along with the sealing disc 16, and through the spring 7, the support disc 4 is closely attached to the large end of the engine, thereby restricting the swing of the airtight fixture. The material of the support disc is aluminum, and the purpose is to reduce the weight of the airtight fixture.

[0062] Four observation holes are evenly distributed on the support disc 4 for observing the position of the airtight fixture inside the engine and checking whether there is leakage of the airtight fixture during the airtight process.

[0063] The backup nut 11 is installed on the large nut 2 for connecting the long pull rod 5 and the large nut 2 into one body.

[0064] As Figures 7 - 8As shown, the flap 17 is in the shape of a sector, and the outer circle diameter is larger than the engine throat diameter, so that the flap can be stuck above the engine throat; a chamfer is provided on the outer periphery of the flap 17 for fitting with the inner wall of the engine; both sides of the flap 17 are flat surfaces, so that the flap 17 can enter the engine throat when tilted; there is a rectangular groove in the middle of the flap 17 for passing through the outer fork 5-1 and the short pull rod 6; two groups of through holes are provided on the flat surfaces on both sides of the flap 17 for installing pin shafts. One group is on the center line of the flap 17 for connecting with the outer fork 5-1 through the point pin shaft 93, and the other group is at a certain distance from the center line for installing the short pull rod 6 through the second pin shaft 92. Rubber coating treatment is carried out on all outer surfaces of the flap 17 to prevent the flap 17 from causing bumps and scratches to the engine during the airtight test.

[0065] When the airtight fixture enters the engine, the flap is in an inclined state. After the flap completely enters the engine throat, pull the handle to make the flap in a state perpendicular to the engine axis, and position the flap above the engine throat; then rotate the large nut, and the sealing disc moves towards the engine throat direction until the large nut cannot be rotated. At this time, the flap and the throat sealing ring on the sealing disc clamp the engine, and at the same time, the support disc fits with the large end of the engine under the action of the spring, realizing the fixation of the airtight fixture on the engine. Connect the external air source to the intake pipe, and the airtight test of the engine can be realized.

[0066] The anti-loosening clamp 10 is composed of two half-rings and can be opened and closed. After the anti-loosening clamp 10 is opened, it is installed between the handle 1 and the tightening nut 15-5 of the intake pipe 15, and is locked after closing to prevent the flap 15 from being unevenly stressed or improperly operated during the airtight test, causing the flap 15 to become inclined, resulting in the axial movement of the intake pipe 15, and thus causing the airtight fixture to be ejected from the engine.

[0067] The usage method of the above-mentioned airtight fixture for liquid rocket engines includes the following steps:

[0068] S1 Hold the tightening handwheel 3 and rotate the large nut 2 counterclockwise to raise the flap 17 to the highest point;

[0069] S2 Hold the tightening handwheel 3, push the handle 1 to make the flap 17 in an inclined state to the maximum position, firmly hold the airtight fixture and slowly put it into the engine throat, so that the flap 17 is above the throat until the support disc 4 abuts against the large end face of the engine;

[0070] S3 Pull the handle 1 to turn the flap 17 to the "horizontal" state;

[0071] S4 Install the anti-loosening clamp 10 between the handle 1 and the tightening nut 15-5 to limit the movement of the handle 1. S5 Pull the handle 1 downward with hand and rotate the large nut 2 clockwise to clamp the engine with the sealing disc 16 and the flap 17. At this time, the airtight fixture reaches the sealing position;

[0072] S6 connects the external air source to the air inlet nozzle 15-1 of the air inlet pipe 15 to inflate the inner cavity of the engine for the airtightness test;

[0073] After the airtightness test is completed, rotate the large nut 2 counterclockwise to raise the flap to the highest point;

[0074] S8 Remove the anti-loosening clamp 10 and push the handle 1 upward to turn the flap 17 to the inclined position;

[0075] S9 Take out the airtight fixture from the engine.

[0076] Embodiment:

[0077] As Figure 1 and Figure 2 , in this embodiment, the airtight fixture of the liquid rocket engine of the present invention includes: handle 1, large nut 2, tightening handwheel 3, support disk 4, long pull rod 5, short pull rod 6, spring 7, set screw 8, first pin shaft 91, second pin shaft 92, third pin shaft mark 93, anti-loosening clamp 10, spare tightening nut 11, first sealing ring 12, second sealing ring 13, throat sealing ring 14, air inlet pipe 15, sealing disk 16, flap 17.

[0078] As Figure 3 shown in the structural schematic diagram of the air inlet pipe 15, first weld the long connecting pipe 15-2, short connecting pipe 15-3, and air inlet nozzle 15-4 together. Among them, the short connecting pipe 15-3 is provided with a flange, and a sealing groove is opened on the flange for installing the first sealing ring 12; then after the tightening nut 15-5 is sleeved on the short connecting pipe, weld the air inlet nozzle 15-4 to the short connecting pipe 15-3. The tightening nut 15-5 can only move between the air inlet nozzle 15-4 and the flange of the short connecting pipe 15-3. The above parts form the air inlet pipe 15. A through hole is opened in the center of the air inlet pipe 15 for introducing gas into the engine during the airtightness test.

[0079] As Figure 4 and Figure 5 shown, the long pull rod 5 is a hollow tubular structure, which is welded by an outer fork 5-1, a guide pipe 5-2, and a joint 5-3. A rectangular groove with a certain length is provided in the middle of the outer fork 5-1, and the short pull rod 6 is installed in the rectangular groove; a plane with a certain length is provided on the outer circular surface of the outer fork 5-1 for passing through the flap 17. A limit groove is opened on the outer wall of the guide pipe 5-2. After the set screw 8 passes through the cylinder 16-2 of the sealing disk 16, it is stuck in the limit groove. The outside of the joint 5-3 is connected to the large nut 2 through the spare tightening nut 11; the inside of the joint 5-3 forms a seal with the air inlet pipe 15 and the small sealing ring 12; an internal thread is provided in the inner hole of the joint 5-3 for installing the tightening nut 15-5.

[0080] As Figure 6The schematic diagram of the sealing disc structure is shown. The sealing disc 16 is welded by a disc body 16-1, a cylinder 16-2, and an adjusting cylinder 16-3. A sealing groove is provided in the inner hole of the disc body 16-1 for installing the large sealing ring 13; a profiling groove is provided on the outer side of the disc body 16-1 for installing the throat sealing ring 14. A plurality of small holes of equal size are evenly distributed on the cylinder 16-2 to reduce the weight of the airtight fixture. A set screw 8 is installed on the cylinder 16-2, and the set screw 8 is stuck in the limit groove on the guide tube 5-2. The outer side of the adjusting cylinder 16-3 is a trapezoidal thread, which is connected to the large nut 2.

[0081] As Figure 7 and Figure 8 shown, the flap 17 is in a sector shape, and the outer diameter of the outer circle is larger than the diameter of the engine throat, so that the flap can be stuck above the engine throat; a chamfer is provided on the outer periphery of the flap 17 for fitting with the inner wall of the engine; both sides of the flap 17 are flat surfaces, so that the flap 17 can enter the engine throat when tilted; a rectangular groove is provided in the middle of the flap 17 for passing through the outer fork 5-1 and the short pull rod 6; two groups of through holes are provided on the flat surfaces on both sides of the flap 17 for installing the pin shaft 9. One group is on the center line of the flap 17 for connecting with the outer fork 5-1, and the other group is at a certain distance from the center line for installing the short pull rod 6. The outer surfaces of both sides of the flap 17 are rubber-coated to prevent the flap 17 from causing bumps and scratches to the engine during the airtight test.

[0082] The installation process of the present invention is as follows:

[0083] Fix the handle 1 on the air inlet nozzle 15-4 through the set screw 8;

[0084] Install the small sealing ring 12 on the short connecting pipe 15-3 of the air inlet pipe 15,

[0085] Install the short pull rod 6 on the inner fork 15-1 of the air inlet pipe 15 through the first pin shaft 91 to form a central assembly;

[0086] Put the backup tightening nut 11 on the outside of the joint 5-3 of the long pull rod 5;

[0087] Slowly pass the central assembly through the long pull rod 5 to form a sandwich assembly; at this time, it should be noted that when the first sealing ring 12 enters the joint 5-3 of the long pull rod 5, avoid squeezing the first sealing ring 12;

[0088] Screw the top tightening nut 15-5 into the joint 5-3 of the long pull rod 5;

[0089] Put the large nut 2 on from one end of the outer fork 5-1 of the sandwich assembly, and tighten the backup tightening nut 11 and the large nut 2;

[0090] Install the second sealing ring 13 in the sealing groove of the disc body 16-1, then pass the support disc 4, the spring 7, and the tightening handwheel 3 through the sealing disc 16 in sequence, and fix the tightening handwheel 3 on the sealing disc 16 with the set screw 8 to form the outer layer assembly;

[0091] Pass the sandwich assembly through the outer layer assembly from one end of the adjusting cylinder 16-3, and connect the large nut 2 and the adjusting cylinder 16-3 by threading;

[0092] Install the set screw 8 on the cylinder 16-2 so that the set screw 8 passes through the cylinder 16-2 and is stuck in the limit groove of the guide tube 5-2. There is a gap between the set screw 8 and the guide tube 5-2 here;

[0093] Install the throat sealing ring 14 on the groove of the disc body 16-1;

[0094] Install the flap 17 on the outer fork 5-1 with the third pin 93, and connect the short pull rod 6 and the flap 17 with the second pin 92;

[0095] Hold the tightening handwheel 3, push and pull the handle 1, and observe whether the flap 17 can be in the state between Figure 1 and Figure 2 ;

[0096] The principle of the above solution is:

[0097] As Figure 2 shown, when the airtight fixture enters the engine, the flap 17 is in an inclined state. After the flap 17 completely enters the engine throat, pull the handle 1 to make the flap 17 in the "horizontal" state, as Figure 1 shown, and clamp the flap 17 at the position above the engine throat; then rotate the large nut 2, and the sealing disc 16 moves towards the engine throat direction until the large nut 2 cannot be rotated. At this time, the flap 17 and the throat sealing ring 14 on the sealing disc 16 clamp the engine. At the same time, the support disc 4 fits with the large end of the engine under the action of the spring 7, realizing the fixation of the airtight fixture on the engine. Connect the external air source to the intake pipe, and the airtight test of the engine can be realized.

[0098] The airtight test fixture of the present invention can be widely applied to the sealing field of high-pressure containers, and has the advantages of novel structure, reliable sealing, and simple operation.

[0099] The present invention has been described in detail above in combination with specific embodiments and exemplary examples, but these descriptions should not be construed as limitations on the present invention. Those skilled in the art understand that without departing from the spirit and scope of the present invention, various equivalent substitutions, modifications, or improvements can be made to the technical solutions and their implementation manners of the present invention, and these all fall within the scope of the present invention. The protection scope of the present invention is subject to the appended claims.

[0100] The content not described in detail in the specification of the present invention belongs to the well-known technology of those skilled in the art.

Claims

1. A hermetic fixture for a liquid rocket engine, characterized in that: It includes a handle (1), a large nut (2), a tightening handwheel (3), a support disc (4), a long pull rod (5), a short pull rod (6), a spring (7), a backup tightening nut (11), an air inlet pipe (15), a sealing disc (16), and a flap (17); A first sealing ring (12) and a tightening nut (15-5) are installed on the outside of the air inlet pipe (15), and the tightening nut (15-5) is located below the first sealing ring (12). A first pin shaft is installed at the upper end of the air inlet pipe (15). One end of the short pull rod (6) is connected to the first pin shaft. The above structure forms a central assembly. The central assembly passes through the central through hole of the long pull rod (5), and the two form a sandwich assembly. The lower end of the long pull rod (5) is tightened by the backup tightening nut (11) and the large nut (2). The short pull rod (6) is fixed in the rectangular groove at the upper end of the long pull rod (5). The support disc (4), the spring (7), and the tightening handwheel (3) sequentially pass through the sealing disc (16), and the tightening handwheel (3) is fixed on the sealing disc (16) with a set screw (8) to form an outer layer assembly. A through hole is provided in the center of the outer layer assembly; The sandwich assembly is sleeved in the through hole of the outer layer assembly. The large nut (2) is threadedly connected to the inner wall surface at the lower end of the sealing disc (16). The set screw passes through the sealing disc and is stuck in the limit groove of the long pull rod (5). A first sealing ring (13) is provided at the position where the upper end of the sealing disc (16) contacts the long pull rod. The throat sealing ring (14) is installed on the outside of the upper end of the sealing disc; The flap (17) is of a fan-shaped structure with a rectangular hole machined inside. The upper parts of the long pull rod (5) and the short pull rod (6) are both inserted into the rectangular hole. The long pull rod (5) is fixedly connected to the flap through a third pin shaft, and the short pull rod (6) is fixedly connected to the flap through a second pin shaft; The handle (1) is fixed on the air inlet nozzle (15-4) of the air inlet pipe (15) with a set screw. The air inlet pipe (15) is moved up and down by pushing and pulling the handle (1).

2. The airtight fixture of a liquid rocket engine according to claim 1, characterized in that The air inlet pipe (15) includes an inner fork (15-1), a long connecting pipe (15-2), a short connecting pipe (15-3), an air inlet nozzle (15-4), and a tightening nut (15-5); The inner fork (15-1), the long connecting pipe (15-2), and the short connecting pipe (15-3) are welded in sequence. One end of the air inlet nozzle (15-4) is welded to the short connecting pipe (15-3), and the other end is provided with a flared joint for connecting to an external air source. The short connecting pipe (15-3) is provided with a flange, and a sealing groove is provided on the flange for installing the first sealing ring (12). The tightening nut (15-5) is installed on the short connecting pipe (15-3) and is located below the flange; The upper end of the inner fork (15-1) is provided with a first pin shaft. There is a rectangular groove with a certain length in the middle of the inner fork (15-1) for installing the short pull rod (6). There is a flange with a certain length on the outer side of the inner fork (15-1) for forming a clearance fit with the inner hole at the upper end of the long pull rod (5) to play a guiding role when the air inlet pipe (15) moves up and down. The handle (1) is fixed on the air inlet nozzle (15-4) of the air inlet pipe (15) by a set screw. A through hole is opened in the center of the air inlet pipe (15) for introducing gas into the engine during the airtight test.

3. The airtight fixture for a liquid rocket engine according to claim 2, characterized in that The long pull rod (5) is sequentially welded by an outer fork (5-1), a guide pipe (5-2), and a joint (5-3). There is a rectangular groove with a certain length at the front end of the outer fork (5-1), and the short pull rod (6) is installed in the rectangular groove. The outer fork (5-1) and the flap (17) are connected by a second pin shaft. There is a plane with a certain length on the outer cylindrical surface of the outer fork (5-1) for passing through the flap (17). A limit groove is opened on the outer wall of the guide pipe (5-2), and the set screw (8) passes through the sealing disc (16) and is stuck in the limit groove. When the large nut (2) rotates, it can limit the long pull rod (5) to move only up and down along the engine axis without rotating. The outer side of the joint (5-3) is connected to the large nut (2) by a backup nut (11). The inner side of the joint (5-3) forms a seal with the air inlet pipe (15) and the first sealing ring (12). The inner hole of the joint (5-3) is provided with an internal thread for fixedly connecting with the tightening nut (15-5) to prevent the air inlet pipe (15) from sliding out of the long pull rod (5) during the airtight process.

4. A hermetic fixture for a liquid rocket engine according to claim 1, characterized in that, Both the left and right ends of the large nut (2) are internal thread structures. One end is connected to the sealing disc (16), and the other end connects the large nut (2) and the long pull rod (5) together through a backup nut (11). By rotating the large nut (2), the long pull rod (5) can drive the flap (17) to move up and down along the engine axis.

5. The airtight fixture for a liquid rocket engine according to claim 1, characterized in that, One end of the short pull rod (6) is connected to the inner fork (15-1) of the air inlet pipe (15) by a first pin shaft, and the other end is connected to the flap (17) by a second pin shaft. By pushing and pulling the handle (1), the flap (17) can be rotated by a certain angle around the center.

6. The airtight fixture of a liquid rocket engine according to claim 3, characterized in that The sealing disc (16) is sequentially welded by a disc body (16-1), a cylinder (16-2), and an adjusting cylinder (16-3). A plurality of holes with equal sizes are evenly distributed on the cylinder (16-2) for reducing the weight of the airtight fixture. The set screw (8) is installed on the cylinder (16-2), and the set screw (8) is stuck in the limit groove on the guide pipe (5-2). The outer side of the adjusting cylinder (16-3) is a trapezoidal thread for connecting with the large nut (2). The inner hole of the disc body (16-1) is provided with a sealing groove for installing the second sealing ring (13). The outer side of the disc body (16-1) is provided with a profiling groove for installing the throat sealing ring (14) to achieve the seal between the airtight fixture and the inner wall of the engine.

7. The airtight fixture for a liquid rocket engine according to claim 6, wherein The throat sealing ring (14) has a certain compressibility, and the cross-sectional diameter is greater than 20 mm.

8. The airtight fixture for a liquid rocket engine according to claim 1, wherein The materials of the tightening handwheel and the support disc are both aluminum.

9. A hermetic fixture for a liquid rocket engine according to claim 1, characterized in that, The spring (7) is a cylindrical compression spring, installed between the tightening handwheel (3) and the support disc (4), and is used to press the support disc (4) against the large end face of the engine.

10. The airtight fixture for a liquid rocket engine according to claim 1, wherein, A guiding hole is provided at the center of the support disc (4), which is sleeved on the cylinder (16-2) of the sealing disc (16). When the large nut (2) is rotated, the tightening handwheel (3) moves upward along with the sealing disc (16), and the support disc (4) is closely attached to the large end of the engine through the spring (7), thereby restricting the swing of the airtight fixture.

11. A liquid rocket engine airtight fixture according to claim 1, characterized in that, Four observation holes are evenly distributed on the support disc (4), which are used to observe the position of the airtight fixture inside the engine and check whether there is leakage in the airtight fixture during the airtight process.

12. The airtight fixture for a liquid rocket engine according to claim 3, characterized in that, The flap (17) is in a sector shape, and the outer circle diameter is larger than the diameter of the engine throat, so that the flap can be stuck above the engine throat; a chamfer is provided on the outer periphery of the flap (17) for fitting with the inner wall of the engine; both sides of the flap are flat surfaces, so that the flap can enter the engine throat when tilted; a rectangular groove is provided in the middle of the flap for the outer fork (5-1) and the short pull rod (6) to pass through; two groups of through holes are provided on the flat surfaces on both sides of the flap for installing the second pin shaft and the third pin shaft. One group is on the center line of the flap and is used to connect with the outer fork (5-1) through the third pin shaft, and the position of the other group is at a certain distance from the center line and is used to connect with the short pull rod (6) through the second pin shaft.

13. A method for using an airtight fixture of a liquid rocket engine, characterized in that, It includes the following steps: S1 Hold the tightening handwheel (3) and rotate the large nut (2) counterclockwise to raise the flap (17) to the highest point. S2 Hold the tightening handwheel (3), push the handle (1) to make the flap (17) in an inclined state to the maximum position, firmly hold the airtight fixture and slowly place it into the engine throat, so that the flap (17) is above the throat until the support disc (4) abuts against the large end face of the engine. S3 Pull the handle (1) to turn the flap (17) to the "horizontal" state. S4 Install the anti-loosening clamp (10) between the handle (1) and the tightening nut (15-5) of the air inlet pipe (15) to restrict the movement of the handle (1). S5 Pull the handle downward by hand and rotate the large nut clockwise to clamp the engine with the sealing disc and the flap. At this time, the airtight fixture reaches the sealing position. S6 Connect the external air source to the inner fork (15-1) of the air inlet pipe (15) to inflate the inner cavity of the engine for an airtight test. S7 After the airtight test is completed, rotate the large nut counterclockwise to raise the flap to the highest point. S8 Remove the anti-loosening clamp (10) and push the handle upward to turn the flap to the inclined position. S9 Take out the airtight fixture from the engine.

14. The method for using a liquid rocket engine airtight fixture according to claim 13, characterized in that, The anti-loosening clamp (10) is composed of two half rings and can be opened and closed; after the anti-loosening clamp (10) is opened, it is installed between the handle (1) and the tightening nut (15-5) of the air inlet pipe (15), and is locked after closing to prevent the flap (17) from being unevenly stressed or improperly operated during the airtight test, causing the flap (17) to become inclined and the air inlet pipe (15) to axially move, resulting in the airtight fixture being ejected from the engine.

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