Dual-fuel engine jet assembly air tightness test tool and test method

Abstract

The invention discloses an air tightness test tool and test method for a dual-fuel engine air injection assembly in the technical field of dual-fuel engine component detection, the test tool comprises a first sealing cover plate, two groups of symmetrically arranged side face test cover plates and a second sealing cover plate, the second sealing cover plate comprises an upper cover plate and a second connecting pipe, and the upper cover plate and the second connecting pipe are connected through a first connecting pipe and a second connecting pipe. The upper cover plate is fixed on an upper interface of the double-wall connecting pipe, the second connecting pipe is arranged on the upper cover plate, one end of the second connecting pipe is used for being communicated with the natural gas chamber, and the other end of the second connecting pipe is used for being connected with external equipment for supplying compressed gas through the detection connecting piece. When the ball valve in the detection connecting piece is closed, the two groups of sealing plates can be driven by the transmission part to be close to each other to seal the inner cavity of the connecting seat, so that the leakage of compressed gas in each cavity caused by internal leakage due to abrasion of a sealing surface or invasion of impurities in long-term use of the ball valve is effectively prevented; and the stability of pressure reading and the accuracy and reliability of a test result in the detection process are ensured.

Description

Technical Field

[0001] This invention relates to the field of dual-fuel engine component testing, specifically to a testing fixture and method for the airtightness testing of a dual-fuel engine jet assembly. Background Technology

[0002] As attached Figure 3 As shown, the jet assembly of the dual-fuel engine includes a double-walled connector, a pipe seat, and a natural gas injection pipe. The double-walled connector and the pipe seat are fixedly connected as one unit. The double-walled connector has a natural gas chamber and a vacuum chamber. The top of the double-walled connector also has an upper interface for installing an injection valve. Its inner side communicates with the natural gas chamber. One end of the natural gas injection pipe communicates with the inner cavity of the upper interface, and the other end passes through the pipe seat and extends to the bottom of the pipe seat. A portion of the outer wall of the natural gas injection pipe is located in the vacuum chamber. The gas enters the injection valve in the inner cavity of the upper interface from the natural gas chamber, and then is ejected from the injection valve through the natural gas injection pipe, and finally directly enters the combustion chamber for combustion. Publication number CN112284621B discloses a dual-fuel engine jet assembly sealing detection device and method. Although this detection device can effectively detect whether there is a leak in the natural gas chamber, it still has the following drawbacks: The device relies on the opening and closing of a ball valve to control the compressed gas filling the natural gas chamber and maintain the pressure after the pressure reaches the preset value. However, in long-term repetitive tests, the ball valve needs to be operated frequently, and it is easy to produce undetectable internal leakage due to wear of the sealing surface. This leakage will cause the pressure in the natural gas chamber to drop, affecting the accuracy of the test results. This device can only effectively detect whether there is a leak in the natural gas chamber, but it cannot effectively detect the sealing of the vacuum chamber and the natural gas injection pipe, so its use has certain limitations. To this end, we propose a testing fixture and method for the airtightness of jet components in a dual-fuel engine. Summary of the Invention

[0003] The purpose of this invention is to provide a testing fixture and method for the air tightness of a dual-fuel engine jet assembly. It solves the technical problem that existing testing devices rely on the opening and closing of ball valves to control the compressed gas filling into the natural gas chamber and maintain the pressure after it reaches a preset value. However, in long-term repetitive tests, the ball valve needs to be operated frequently, which can easily cause undetectable internal leakage due to wear of the sealing surface. This leakage will lead to a drop in the pressure of the natural gas chamber and affect the accuracy of the test results.

[0004] The present invention achieves the above objectives through the following technical solutions: A dual-fuel engine jet assembly air tightness testing fixture is used to test the jet assembly. The jet assembly includes a double-walled connector, a pipe seat, and a natural gas injection pipe. The testing fixture includes a sealing cover plate for sealing the output end of the natural gas injection pipe, two sets of symmetrically arranged side test cover plates, and a sealing cover plate second. The sealing cover plate second includes an upper cover plate and a second connector. The upper cover plate is fixed to the upper interface of the double-walled connector. The second connector is located on the upper cover plate, with one end for communicating with the natural gas chamber and the other end for connecting to an external compressed gas supply device through a test connector. The detection connector includes a connecting pipe for connecting to the second connecting pipe, a pressure gauge on the connecting pipe, a connecting seat communicating with one end of the connecting pipe, a ball valve communicating with the connecting seat, a connecting head communicating with the ball valve, and a compressed gas pipe body communicating with the connecting head at one end and with a compressed gas supply device connected to the outside at the other end. The inner walls of both sides of the connecting seat are symmetrically provided with grooves, and sealing plates are slidably provided in the grooves. The two sets of sealing plates are connected to the ball valve through a transmission part. When the ball valve is closed, the transmission part drives the two sets of sealing plates to move closer to each other and close the inner cavity of the connecting seat.

[0005] A further improvement is that the side test cover includes a side sealing cover fixed to the end of the double-walled pipe, and the side sealing cover has a plurality of vent holes on one side for communicating with the vacuum chamber inside the double-walled pipe.

[0006] A further improvement is that the transmission part includes a bidirectional screw, the two ends of which extend into two grooves and are rotatably connected to the bottom of the grooves. The two sets of sealing plates are threaded onto the two ends of the outer wall of the bidirectional screw. One end of the bidirectional screw is connected to a shaft through a worm gear transmission group, and the shaft is rotatably disposed in a groove. One end of the shaft extends to the outside of the connecting seat and is connected to the valve stem of the ball valve through a sprocket and chain transmission group.

[0007] A further improvement is that a sealing structure is embedded at the contact position between the groove opening and the sealing plate.

[0008] A further improvement is that a magnetic block one is embedded on one side of the ball valve handle, and a magnetic block two that attracts the magnetic block one is embedded on one side of the connecting seat. A cover plate for blocking the magnetic block two is elastically hinged on one side of the connecting seat. One end of the cover plate is connected to a pull rope, and one end of the pull rope extends into the wall thickness of the connecting seat and is wound around the outer wall of the shaft. When the ball valve is closed, the shaft is driven by the transmission unit to rotate and rewind the rope, causing the cover plate to flip open so that the magnetic block one and magnetic block two on the ball valve handle are attracted to each other.

[0009] A further improvement is that the connector is also connected to a branch pipe, and both the branch pipe and the compressed gas pipe are equipped with solenoid valves. On the branch pipe and inside the solenoid valve, a detection sensor is also provided on the side near the connector. The detection sensor is used to collect compressed gas data when the ball valve is closed. The detection sensor is connected to an external controller, and the external controller is connected to an alarm.

[0010] A further improvement is that a sealing element 1 is detachably provided on one side of the upper cover plate for fitting into the inner cavity of the upper interface of the double-walled pipe. A flow groove is provided on the side of the sealing element 1 away from the upper cover plate. An opening is provided on one side of the sealing element 1 to communicate with the flow groove and the natural gas chamber in the double-walled pipe. A sealing element 2 is detachably provided at the opening of the flow groove for sealing the input end of the natural gas injection pipe.

[0011] A further improvement is that the outer wall of the side sealing cover is provided with an outer rotating ring, and a connecting hole is provided in a ring array on the outer rotating ring. The connecting hole and the vent hole correspond one-to-one. A movable port is also provided on the outer rotating ring, and a connecting pipe is movably provided in the movable port. The connecting pipe is connected to the vacuum chamber inside the double-walled connecting pipe.

[0012] A further improvement is that the side sealing cover has several sets of vent holes II arranged in a ring array on one side for communicating with the natural gas chamber inside the double-walled pipe. The outer wall of the side sealing cover, located inside the outer rotating ring, also has an inner rotating ring, and the inner rotating ring has a connecting hole II arranged in a ring array. The connecting hole II and the vent hole II correspond one-to-one.

[0013] A method for testing the air tightness of a dual-fuel engine jet assembly, utilizing the aforementioned test fixture, includes the following steps: S1: When testing the sealing performance of the natural gas chamber inside the double-walled pipe, first adjust the inner rotating ring so that its connecting hole 2 and vent hole 2 are misaligned and closed. At the same time, adjust the outer rotating ring so that its connecting hole 1 and vent hole 1 are aligned and connected. Then, suspend the jet assembly into the test water tank filled with rust-preventing liquid until it is completely submerged. Open the ball valve to allow compressed gas to enter the flow groove through the compressed gas pipe body, connector, ball valve, connecting seat, connecting pipe and pipe 2, and then fill the natural gas chamber of the double-walled pipe through the port. After the pressure gauge reaches the preset threshold, close the ball valve to stop the gas supply. Maintain the pressure for a preset time and observe whether there are bubbles generated at one of the vent holes in the water. If there are bubbles, it is determined that there is a leak in the natural gas chamber. S2: When testing the airtightness of the vacuum chamber inside the double-walled pipe, first adjust the inner rotating ring so that its connecting hole two is aligned and connected with the vent hole two. At the same time, adjust the outer rotating ring so that its connecting hole one is misaligned and closed with the vent hole one. Disassemble and install the test connector from pipe two to pipe one, and use an external sealing structure to seal pipe two. Hoist the jet assembly into the test water tank until it is completely submerged. Introduce compressed gas so that it enters the vacuum chamber through pipe one. Stop the gas supply after the pressure gauge reaches the preset threshold. Maintain the pressure for a preset time and observe whether there are bubbles generated in the vent hole two and the outer wall of the jet assembly. If there are bubbles, it is determined that there is a leak in the vacuum chamber. S3: When testing the sealing performance of the natural gas injection pipe, first remove the top cover and seal 1, adjust the position of seal 1 so that its opening is misaligned with the natural gas chamber, and remove seal 2. Then reinstall seal 1 and top cover. Next, adjust the outer rotating ring so that its connecting hole 1 is aligned with vent hole 1. Install the test connector on pipe 2. After the injection assembly is fully submerged in the test water tank, compressed gas is introduced. The compressed gas enters the flow groove through pipe 2 and then fills the pipe from the input end of the natural gas injection pipe. After the pressure gauge reaches the preset threshold, stop the gas supply, maintain the pressure for a preset time, and observe whether there are bubbles at vent hole 1. If there are bubbles, it is determined that there is a leak in the natural gas injection pipe. In steps S1, S2 and S3, when the ball valve is closed, the transmission part drives the two sets of sealing plates to move closer to each other and close the inner cavity of the connecting seat.

[0014] The beneficial effects of this invention are as follows: This invention employs a detection connector and a connecting pipe to supply compressed gas. When the ball valve in the detection connector is closed, the transmission part can drive two sets of sealing plates to move closer to each other and close the inner cavity of the connector seat, forming an additional sealing barrier in the inner cavity of the connector seat. This effectively prevents the leakage of compressed gas in each chamber caused by internal leakage of the ball valve due to wear of the sealing surface or intrusion of impurities during long-term use, thus ensuring the stability of the pressure reading and the accuracy and reliability of the test results during the detection process. Secondly, by combining the side test cover plate, sealing cover plate one, and sealing cover plate two, this invention enables independent sealing and testing of the natural gas chamber, vacuum chamber, and natural gas injection pipe inside the double-walled pipe, thereby improving the applicability of the test fixture. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the experimental tooling structure of the present invention; Figure 2 For the present invention Figure 1 Another perspective structural diagram; Figure 3 For the present invention Figure 1 Partial structural sectional view; Figure 4This is a schematic diagram of the detection connector structure of the present invention; Figure 5 This is a cross-sectional view of the connector of the present invention.

[0016] In the diagram: 100, Side test cover plate; 101, Side sealing cover plate; 102, Outer rotating ring; 103, Connecting pipe one; 104, Connecting hole one; 105, Inner rotating ring; 200, Sealing cover plate one; 300, Sealing cover plate two; 301, Upper cover plate; 302, Connecting pipe two; 303, Sealing element one; 304, Through port; 305, Sealing element two; 400, Test connector; 401, Connecting pipe; 402, Pressure gauge; 403, Connecting seat; 404, Ball valve; 40 5. Connector; 406. Compressed gas pipe body; 407. Sealing plate; 408. Double-acting screw; 409. Worm gear drive assembly; 410. Sprocket and chain drive assembly; 411. Magnetic block one; 412. Magnetic block two; 413. Cover plate; 414. Pull rope; 415. Branch pipe; 416. Solenoid valve; 417. Detection sensor; 500. Injection assembly; 501. Double-walled connecting pipe; 502. Pipe seat; 503. Natural gas injection pipe; 504. Natural gas chamber; 505. Vacuum chamber. Detailed Implementation

[0017] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0018] Example 1 Please see the appendix Figure 1-5 A dual-fuel engine jet assembly airtightness testing fixture is used to test the jet assembly 500. The jet assembly 500 includes a double-walled nozzle 501, a pipe seat 502, and a natural gas injection pipe 503. The double-walled nozzle 501 and the pipe seat 502 are fixedly connected as one unit. The double-walled nozzle 501 has a natural gas chamber 504 and a vacuum chamber 505. The top of the double-walled nozzle 501 also has an upper interface (i.e., an auxiliary interface). Figure 2 As shown in Figure A), the upper interface is used to install the injection valve. Its inner side communicates with the natural gas chamber 504. One end of the natural gas injection pipe 503 is connected to the inner cavity of the upper interface, and the other end passes through the pipe seat 502 and extends to the bottom of the pipe seat 502. A portion of the outer wall of the natural gas injection pipe 503 is located in the vacuum chamber 505. The gas enters the injection valve in the inner cavity of the upper interface from the natural gas chamber 504, and then is ejected from the injection valve through the natural gas injection pipe 503. Finally, it directly enters the combustion chamber for combustion. The above-mentioned injection assembly 500 is a conventional structure in the art and will not be described in detail here. The test fixture of the present invention includes a sealing cover plate 200 for sealing the output end of the natural gas injection pipe 503, two sets of symmetrically arranged side test cover plates 100, and a sealing cover plate 300. The sealing cover plate component 200 is widely used in the field. Optionally, the sealing cover plate component 200 of this embodiment includes a lower cover plate and a sealing sleeve. The top end of the sealing sleeve is welded and fixed to the center through hole of the lower cover plate. The lower end of the vertical pipe body of the natural gas injection pipe 503 passes through the pipe seat 502 and the lower cover plate in sequence and extends into the sealing sleeve. The outer circle of the vertical pipe body of the natural gas injection pipe 503 and the center hole of the lower cover plate are sealed by the lower O-ring seal embedded in the wall of the center hole of the lower cover plate. Several fastening screws passing through the pipe seat 502 from top to bottom fix the lower sealing cover plate to the lower end port of the pipe seat 502. A fixing sealing plate is welded to the bottom of the sealing sleeve. The inner diameter of the sealing sleeve is larger than the outer diameter of the natural gas injection pipe 503. The length of the lower part of the vertical pipe body of the natural gas injection pipe 503 extending into the sealing sleeve is less than the inner length of the sealing sleeve, so that the lower part of the vertical pipe body can smoothly extend into the sealing sleeve. The side test cover plate 100 is widely used in the art. Optionally, the side test cover plate 100 of this embodiment includes a side sealing cover plate 101 fixed to the end of the double wall pipe 501. The side sealing cover plate 101 has a plurality of vent holes arranged in a ring array on one side for communicating with the vacuum chamber 505 inside the double wall pipe 501. The side sealing cover plate 101 is fixed to the outer wall of the end of the double wall pipe 501 by screws. The side sealing cover plate 101 is sealed to the end face of the natural gas chamber 504 and the vacuum chamber 505 of the double wall pipe 501 by embedded sealing rings. The sealing cover plate component 300 includes an upper cover plate 301 and a second connecting pipe 302. The upper cover plate 301 is fixed to the upper interface of the double-walled connecting pipe 501 by screws. The second connecting pipe 302 is located on the upper cover plate 301. One end of the pipe is used to communicate with the natural gas chamber 504, and the other end is used to connect with an external compressed gas supply device through a detection connector 400. The compressed gas supplied by the compressed gas supply device is preferably compressed air or compressed nitrogen. The detection connector 400 includes a connecting pipe 401 for connecting to the second connecting pipe 302. The connecting pipe 401 and the second connecting pipe 302 can be connected by threads. When the second connecting pipe 302 is not connected to the connecting pipe 401, one end of it can be sealed by an external sealing structure (such as a sealing cap). A pressure gauge 402 is provided on the connecting pipe 401. A connecting seat 403 communicates with one end of the connecting pipe 401. A ball valve 404 communicates with the connecting seat 403. A connecting head 405 communicates with the ball valve 404. A compressed gas pipe 406 has one end communicating with the connecting head 405 and the other end communicating with an external compressed gas supply device. Optionally, in this embodiment, the connecting seat 403 has a rectangular vertical cross-section. A pair of circular grooves are coaxially formed at both ends of the connecting seat 403 for connecting and installing the connecting pipe 401 and the ball valve 404, respectively. A rectangular connecting port is formed through the central part, which is connected to the circular grooves at both ends, forming a fluid channel that runs through the entire connecting seat 403. Grooves are symmetrically formed on the inner walls of both sides of the connecting seat 403 (located inside the rectangular connecting port), and sealing plates 407 are slidably installed in the grooves. The two sets of sealing plates 407 are connected to the ball valve 404 through a transmission unit. When the ball valve 404 is closed, the transmission unit drives the two sets of sealing plates 407 to move closer together to seal the inner cavity of the connecting seat 403. In addition to the sealing of the ball valve 404 itself, this method forms an additional sealing barrier in the inner cavity of the connecting seat 403, effectively preventing the leakage of compressed gas in each chamber caused by internal leakage due to wear of the sealing surface or intrusion of impurities during long-term use of the ball valve 404, thus ensuring the stability of pressure readings and the accuracy and reliability of test results during the testing process.

[0019] Preferably, in this embodiment, a sealing element 303 is detachably provided on one side of the upper cover plate 301 for fitting with the inner cavity of the upper interface of the double-walled pipe 501. The sealing element 303 is detachably connected to the upper cover plate 301 using a screw-like structure. The sealing element 303 is a cylindrical member with multiple sealing rings embedded on its outer periphery to achieve a tight seal with the inner wall of the upper interface of the double-walled pipe 501. A flow groove is provided on the side of the sealing element 303 away from the upper cover plate 301, and a connection is provided on the other side of the sealing element 303 to the flow groove and the natural gas chamber 504 inside the double-walled pipe 501. The through port 304 has a detachable sealing element 305 at the opening of the flow groove for sealing the input end of the natural gas injection pipe 503. The sealing element 305 is a circular sealing plate 407. The sealing element 305 can be detachably connected to the sealing element 303 by snap-fit ​​or screws. This sealing structure is not only easy to assemble, disassemble and maintain, but can also be used in combination to achieve targeted sealing for different test objects (such as natural gas chamber 504 or injection pipe), effectively improving the adaptability and sealing reliability of the test fixture, while reducing the overall replacement cost of sealing elements.

[0020] Preferably, in this embodiment, the outer wall of the side sealing cover plate 101 is provided with an outer rotating ring 102 via a bearing, and the outer rotating ring 102 is provided with a through-hole 104 in a ring array. The through-hole 104 and the vent hole 104 correspond one-to-one, that is, the two are the same in number. One of the outer rotating rings 102 is also provided with a movable opening, which is arc-shaped. The movable opening is provided with a connecting pipe 103, which is connected to the vacuum chamber 505 inside the double-walled connecting pipe 501. The connecting pipe 103 can be connected to the detection connector 400. The setting of the movable opening ensures that the connecting pipe 103 will not be interfered with when rotating the outer rotating ring 102. In this way, the on-off state of the vent hole 1 can be controlled by simply rotating the outer rotating ring 102. While maintaining the stable connection of the connecting pipe 103, the flexible opening and closing of the vacuum chamber 505 channel is realized, which effectively improves the convenience of operation.

[0021] Preferably, in this embodiment, the side sealing cover plate 101 has several sets of vent holes arranged in a ring array on one side for communicating with the natural gas chamber 504 inside the double-walled pipe 501. The outer wall of the side sealing cover plate 101, located inside the outer rotating ring 102, also has an inner rotating ring 105 that rotates coaxially via a bearing. The inner rotating ring 105 has two connecting holes arranged in a ring array. The two connecting holes and the two vent holes correspond one-to-one, that is, the two are the same in number. In this way, the opening and closing state of the two vent holes can be controlled by simply rotating the inner rotating ring 105, realizing the flexible opening and closing of the natural gas chamber 504 channel and effectively improving the ease of operation.

[0022] A method for testing the air tightness of a dual-fuel engine jet assembly 500, utilizing the aforementioned test fixture, includes the following steps: S1: When testing the sealing performance of the natural gas chamber 504 inside the double-walled pipe 501, first adjust the inner rotating ring 105 so that its connecting hole 2 and vent hole 2 are misaligned and closed. At the same time, adjust the outer rotating ring 102 so that its connecting hole 104 and vent hole 1 are aligned and connected. Then, suspend the jet assembly 500 into the test water tank filled with rust-preventing liquid until it is completely submerged. Open the ball valve 404 so that the compressed gas enters the flow groove through the compressed gas pipe 406, connector 405, ball valve 404, connector 403, connecting pipe 401 and connecting pipe 2 302. Then, it fills the natural gas chamber 504 of the double-walled pipe 501 through the port 304. After the value displayed by the pressure gauge 402 reaches the preset threshold, close the ball valve 404 to stop the gas supply. Hold the pressure for a preset time and observe whether there are bubbles generated at one of the vent holes in the water. If there are bubbles, it is determined that there is a leak in the natural gas chamber 504. S2: When testing the sealing performance of the vacuum chamber 505 inside the double-walled connecting pipe 501, first adjust the inner rotating ring 105 so that its connecting hole 2 is aligned and connected with the vent hole 2. At the same time, adjust the outer rotating ring 102 so that its connecting hole 104 is misaligned and closed with the vent hole 1. Disassemble and install the test connector 400 from the connecting pipe 2 302 to the connecting pipe 1 103, and seal the connecting pipe 2 302 with an external sealing structure. Hoist the jet assembly 500 into the test water tank until it is completely submerged. Introduce compressed gas so that it enters the vacuum chamber 505 through the connecting pipe 1 103. Stop the gas supply after the value displayed on the pressure gauge 402 reaches the preset threshold. Maintain the pressure for a preset time and observe whether there are bubbles generated in the vent hole 2 and the outer wall of the jet assembly 500. If there are bubbles, it is determined that there is a leak in the vacuum chamber 505. S3: When testing the sealing performance of the natural gas injection pipe 503, first remove the upper cover plate 301 and the first seal 303, adjust the position of the first seal 303 so that its port 304 is misaligned with the natural gas chamber 504, and remove the second seal 305. Then reinstall the first seal 303 and the upper cover plate 301. Next, adjust the outer rotating ring 102 so that its connecting hole 104 is aligned with the first vent hole. Install the test connector 400 on the second pipe 302. After the injection assembly 500 is fully submerged in the test water tank, compressed gas is introduced. The compressed gas enters the flow groove through the second pipe 302 and then fills the pipe from the input end of the natural gas injection pipe 503. After the pressure gauge 402 reaches the preset threshold, stop the gas supply, maintain the pressure for a preset time, and observe whether there are bubbles at the first vent hole. If there are bubbles, it is determined that there is a leak in the natural gas injection pipe 503. In steps S1, S2 and S3, when the ball valve 404 is closed, it drives the two sets of sealing plates 407 to move closer to each other and close the inner cavity of the connecting seat 403 through the transmission part.

[0023] Example 2 Please see the appendix Figure 4-5Based on Embodiment 1, the transmission part of this embodiment includes a bidirectional screw 408. Both ends of the bidirectional screw 408 extend into two grooves and are rotatably connected to the bottom of the grooves via bearings. Two sets of sealing plates 407 are threaded onto the reverse threads at both ends of the outer wall of the bidirectional screw 408. The length of the sealing plate 407 is less than the length of the groove to ensure sliding stroke, and greater than half the length of the inner cavity of the connecting seat 403 to ensure the coverage area during sealing. One end of the bidirectional screw 408 is connected to a worm gear transmission assembly 409 (the worm gear transmission assembly 409 includes components disposed on the bidirectional screw...). A shaft is connected to the worm gear on the outer wall of one end of the rod 408 and the worm wheel meshing with the worm gear. The shaft is rotatably disposed in a groove and is perpendicular to the double-acting screw 408. One end of the shaft extends to the outside of the connecting seat 403 and is connected to the valve stem of the ball valve 404 via a sprocket and chain drive assembly 410. The sprocket and chain drive assembly 410 includes a sprocket and a chain. The connecting seat 403 has an opening in its wall for the chain to pass through. It should be noted that the ball valve 404 is a conventional structure in this field. The ball valve 404 includes a tube body, valve stem, and handle, etc., as shown in the attached figure. Figure 4 As shown, when the handle is in a horizontal position, the ball valve 404 is in the open position. When the handle is rotated downwards to the vertical position, the ball valve 404 is in the closed position. The rotation of the ball valve 404 handle drives the valve stem, which is then converted into the opposing linear motion of the two sets of sealing plates 407 through the sprocket chain, worm gear and double screw 408. It is easy to use and realizes double sealing linkage under a single operation, ensuring the stability of pressure readings and the accuracy and reliability of test results during the detection process.

[0024] Preferably, a sealing structure is embedded at the contact position between the groove opening and the sealing plate 407 in this embodiment. The sealing structure is preferably a sealing strip, and more preferably a wear-resistant and elastic sealing strip, to prevent compressed gas from entering the groove.

[0025] Preferably, in this embodiment, a magnetic block 411 is embedded on one side of the handle of the ball valve 404, and a magnetic block 412 that attracts the magnetic block 411 is embedded on one side of the connecting seat 403. A cover plate 413 for blocking the magnetic block 412 is elastically hinged to one side of the connecting seat 403. The cover plate 413 and the connecting seat 403 can be elastically hinged by a pivot and a torsion spring. It should be noted that the opening trajectory of the cover plate 413 does not interfere with the rotation path of the ball valve 404 handle, i.e., as shown in the attached figure. Figure 4 As shown, the handle is closed by rotating it downwards, and the cover plate 413 is opened by rotating it counterclockwise without interfering with the downward rotation of the handle. One end of the pull rope 414 is connected to the cover plate 413. One end of the pull rope 414 extends into the wall thickness of the connecting seat 403 and is wound around the outer wall of the shaft. A guide wheel assembly (including a support and a guide wheel rotatably installed in the support) can be provided on the connecting seat 403 to guide the pull rope 414. A channel for the movement of the pull rope 414 is opened on one side of the wall thickness of the connecting seat 403. When the ball valve 404 is closed, the shaft is driven by the transmission unit to rotate and rewind the pull rope 414, causing the cover plate 413 to flip open. This allows the magnetic block 411 on the handle of the ball valve 404 to attract the magnetic block 412. This magnetic attraction effectively locks the ball valve 404 in the closed state, preventing accidental opening due to accidental contact or other factors. This ensures the stability of the chamber pressure during the testing process and guarantees the accuracy and reliability of the test results. When the ball valve 404 is opened, the transmission unit moves in the opposite direction to release the pull rope 414. The cover plate 413 automatically resets and flips to the closed position under the action of the torsion spring, covering the magnetic block 412 inside. This provides protection against dust, impact, and corrosion, effectively maintaining the adsorption performance and service life of the magnetic structure.

[0026] Example 3 Please see the appendix Figure 4 Based on Embodiment 1, in this embodiment, the connector 405 is also connected to a branch pipe 415. Both the branch pipe 415 and the compressed gas pipe 406 are equipped with solenoid valves 416. On the branch pipe 415 and inside the solenoid valve 416, a detection sensor 417 is also provided on the side near the connector 405. The detection sensor 417 is used to collect compressed gas data (compressed gas parameters flowing through the branch pipe 415) when the ball valve 404 is closed. The detection sensor 417 is connected to an external controller, and the external controller is connected to an alarm. When testing for air tightness, the jet assembly 500 is lowered into a test water tank filled with rust-preventive liquid until it is completely submerged. The operator then leads the end of the branch pipe 415 out of the water, closes the solenoid valve 416 in the compressed gas pipe 406, and opens the solenoid valve 416 in the branch pipe 415 to connect the branch pipe 415 to the atmosphere. At this time, the compressed gas at the front end of the ball valve 404 is discharged to the outside through the branch pipe 415. After discharge, the detection sensor 417 is opened. If there is a leak at the sealing plate 407 and the ball valve 404, the leaked compressed gas will be discharged along the branch pipe 415 and detected in real time by the detection sensor 417. The detection sensor 417 then sends a signal to the controller, which triggers the alarm to realize real-time monitoring and fault warning of the sealing status of the entire air intake passage. The detection sensor 417 can be any one of a pressure sensor, a flow sensor, or a gas concentration sensor.

[0027] The above embodiments are merely illustrative of several implementation methods of the present invention, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.

Claims

1. A test fixture for the air tightness of a dual-fuel engine jet assembly, used to test a test jet assembly (500), the jet assembly (500) comprising a double-walled connector (501), a pipe seat (502), and a natural gas injection pipe (503), the test fixture comprising a sealing cover plate first (200) for sealing the output end of the natural gas injection pipe (503), two sets of symmetrically arranged side test cover plates (100), and a sealing cover plate second (300), characterized in that: The sealing cover plate component 2 (300) includes an upper cover plate (301) and a second connecting pipe (302). The upper cover plate (301) is fixed on the interface of the double-walled connecting pipe (501). The second connecting pipe (302) is located on the upper cover plate (301). One end of the pipe is used to communicate with the natural gas chamber (504), and the other end is used to connect with the equipment that supplies compressed gas from the outside through the detection connector (400). The detection connector (400) includes a connecting pipe (401) for connecting to the connecting pipe (302), a pressure gauge (402) on the connecting pipe (401), a connecting seat (403) connected to one end of the connecting pipe (401), a ball valve (404) connected to the connecting seat (403), a connector (405) connected to the ball valve (404), and a compressed gas pipe (406) connected to the connector (405) at one end and to a compressed gas supply device at the other end. The inner walls of the connecting seat (403) are symmetrically provided with grooves, and sealing plates (407) are slidably provided in the grooves. The two sets of sealing plates (407) are connected to the ball valve (404) through a transmission part. When the ball valve (404) is closed, the transmission part drives the two sets of sealing plates (407) to move closer to each other and close the inner cavity of the connecting seat (403).

2. The test fixture according to claim 1, characterized in that, The side test cover plate (100) includes a side sealing cover plate (101) fixed to the end of the double-walled pipe (501). The side sealing cover plate (101) has a plurality of vent holes on one side for communicating with the vacuum chamber (505) inside the double-walled pipe (501).

3. The test fixture according to claim 1, characterized in that, The transmission part includes a bidirectional screw (408), the two ends of which extend into two grooves and are rotatably connected to the bottom of the grooves. Two sets of sealing plates (407) are threaded onto the two ends of the outer wall of the bidirectional screw (408). One end of the bidirectional screw (408) is connected to a shaft through a worm gear transmission group (409), and the shaft is rotatably located in a groove. One end of the shaft extends to the outside of the connecting seat (403) and is connected to the valve stem of the ball valve (404) through a sprocket and chain transmission group (410).

4. The test fixture according to claim 3, characterized in that, A sealing structure is embedded at the contact position between the groove opening and the sealing plate (407).

5. The test fixture according to claim 3, characterized in that, A magnetic block (411) is embedded on one side of the handle of the ball valve (404), and a magnetic block (412) is embedded on one side of the connecting seat (403) to attract the magnetic block (411). A cover plate (413) for blocking the magnetic block (412) is elastically hinged on one side of the connecting seat (403). One end of a pull rope (414) is connected to the cover plate (413). One end of the pull rope (414) extends into the wall thickness of the connecting seat (403) and is wound around the outer wall of the shaft. When the ball valve (404) is closed, the shaft is driven by the transmission unit to rotate the winding rope (414), which drives the cover plate (413) to flip open, so that the magnetic block one (411) on the ball valve (404) handle attracts the magnetic block two (412).

6. The test fixture according to claim 1, characterized in that, The connector (405) is also connected to a branch pipe (415). Both the branch pipe (415) and the compressed gas pipe (406) are equipped with solenoid valves (416). On the branch pipe (415) and inside the solenoid valve (416), a detection sensor (417) is also provided on the side of the connector (405) near the solenoid valve (416). The detection sensor (417) is used to collect compressed gas data when the ball valve (404) is closed. The detection sensor (417) is connected to an external controller, and the external controller is connected to an alarm.

7. The test fixture according to claim 2, characterized in that, The upper cover plate (301) is detachably provided with a sealing element one (303) for adapting to the inner cavity of the interface of the double wall pipe (501) on one side. The sealing element one (303) has a flow groove on the side away from the upper cover plate (301). The sealing element one (303) has an opening (304) on one side that communicates with the flow groove and the natural gas chamber (504) in the double wall pipe (501). The opening of the flow groove is detachably provided with a sealing element two (305) for sealing the input end of the natural gas injection pipe (503).

8. The test fixture according to claim 7, characterized in that, The outer wall of the side sealing cover (101) is provided with an outer rotating ring (102), and the outer rotating ring (102) is provided with a through-hole (104) in a ring array. The through-hole (104) and the vent hole (104) correspond one-to-one. The outer rotating ring (102) is also provided with a movable opening. The movable opening is provided with a connecting pipe (103), and the connecting pipe (103) is connected to the vacuum chamber (505) inside the double-walled connecting pipe (501).

9. The test fixture according to claim 8, characterized in that, The side sealing cover (101) has several sets of vent holes arranged in a ring array on one side for communicating with the natural gas chamber (504) inside the double-walled pipe (501). The outer wall of the side sealing cover (101) and the inner side of the outer rotating ring (102) also has an inner rotating ring (105) arranged in a ring array. The inner rotating ring (105) has two connecting holes arranged in a ring array. The two connecting holes and the two vent holes correspond one-to-one.

10. A method for testing the airtightness of a dual-fuel engine jet assembly, utilizing the test fixture as described in claim 9, characterized in that, Includes the following steps: S1: When testing the sealing performance of the natural gas chamber (504) inside the double-walled pipe (501), first adjust the inner rotating ring (105) so that its connecting hole two and vent hole two are misaligned and closed. At the same time, adjust the outer rotating ring (102) so that its connecting hole one (104) is aligned and connected with vent hole one. Then, lower the jet assembly (500) into the test water tank filled with rust-preventing liquid until it is completely submerged. Open the ball valve (404) to allow compressed gas to pass through the compressed gas pipe body (406) and connector (404). 05) The ball valve (404), connecting seat (403), connecting pipe (401) and connecting pipe 2 (302) enter the flow groove, and then fill the natural gas chamber (504) of the double wall connecting pipe (501) through the port (304). After the value displayed by the pressure gauge (402) reaches the preset threshold, the ball valve (404) is closed to stop the gas supply. The pressure is maintained for a preset time, and it is observed whether there are bubbles generated at one of the vent holes in the water. If there are bubbles, it is determined that there is a leak in the natural gas chamber (504). S2: When testing the sealing performance of the vacuum chamber (505) inside the double-walled connecting pipe (501), first adjust the inner rotating ring (105) so that its connecting hole 2 is aligned with the vent hole 2, and at the same time adjust the outer rotating ring (102) so that its connecting hole 1 (104) is misaligned and closed with the vent hole 1. Disassemble and install the test connector (400) from the connecting pipe 2 (302) to the connecting pipe 1 (103), and use an external sealing structure to seal the connecting pipe 2 (302). Hoist the jet assembly (500) into the test water tank until it is completely submerged, and introduce compressed gas so that it enters the vacuum chamber (505) through the connecting pipe 1 (103). After the pressure gauge (402) reaches the preset threshold, stop the gas supply, maintain the pressure for a preset time, and observe whether there are bubbles generated in the vent hole 2 and the outer wall of the jet assembly (500). If there are bubbles, it is determined that there is a leak in the vacuum chamber (505). S3: When testing the sealing performance of the natural gas injection pipe (503), first remove the upper cover plate (301) and the first seal (303), adjust the position of the first seal (303) so that its port (304) is misaligned with the natural gas chamber (504), and remove the second seal (305). Then reinstall the first seal (303) and the upper cover plate (301), and then adjust the outer rotating ring (102) so that its connecting hole (104) is aligned with the first vent hole. Then, place the test connector (4) 00) Install it on the second connector (302), lower the jet assembly (500) into the test water tank until it is completely submerged, and then introduce compressed gas. The compressed gas enters the flow groove through the second connector (302), and then fills the pipe from the input end of the natural gas injection pipe (503). After the value displayed by the pressure gauge (402) reaches the preset threshold, stop the gas supply, maintain the pressure for a preset time, and observe whether there are bubbles generated at the first vent hole. If there are bubbles, it is determined that there is a leak in the natural gas injection pipe (503). In steps S1, S2 and S3, when the ball valve (404) is closed, it drives the two sets of sealing plates (407) to move closer to each other and close the inner cavity of the sealing connection seat (403) through the transmission part.

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