Low-temperature multifunctional sealing test device

Abstract

A multifunctional sealing test device for low temperature is characterized in that a to-be-tested product end face sealing assembly, a to-be-tested process end face sealing assembly and a to-be-tested leather cup sealing element are symmetrically installed on a rotor assembly and are fixed on a shell assembly, and when the three sealing elements are installed at the same time, the examination test of two product sealing elements can be completed at a time; when only the product end face sealing assembly and the process end face sealing assembly are installed, the sealing capability of the process end face sealing assembly on a gas-liquid two-phase medium is checked; when only a product end face sealing assembly and a leather cup sealing element are installed, the device is used for checking the sealing capability of the leather cup sealing element to a gas-liquid two-phase medium. When only the leather cup sealing element is mounted, the sealing capability of the leather cup sealing element on a liquid nitrogen medium is realized; when only the process end face sealing assembly is installed, the sealing capacity of the process end face sealing assembly to the liquid nitrogen medium can be achieved. According to the invention, multifunctional tests of low-temperature high-speed end face sealing of the turbine pump of the liquid rocket engine, test device process end face sealing and low-temperature packing cup sealing are realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of cryogenic sealing test of liquid rocket engines, and specifically relates to a testing device for evaluating the working performance of cryogenic end face seals and cryogenic leather cup seals in cryogenic liquid media and gas-liquid two-phase media. Background Art

[0002] The performance and reliability of the turbopump, as the heart of the liquid rocket hydrogen-oxygen engine, will affect the reliability of the liquid rocket launch. In the liquid rocket engine models currently in service, the turbopump widely adopts the end face seal structure. As the core and key component of the turbopump, the end face seal is an important link that affects the safe and reliable operation of the turbopump of the liquid rocket engine.

[0003] Before assembling the turbo pump, it is usually necessary to carry out an end face seal test, which is a key link in assessing its sealing performance. With the normalization of space launches, the demand for end face seal tests and reliability requirements are becoming increasingly higher. At present, the domestic patent (CN 108708802 B) has achieved the purpose of testing one low-temperature end face seal at a time, but the efficiency is low; the patent (CN 115541134A) can achieve the operation of two products at a time, but it cannot achieve accurate measurement of the leakage of the two products at the same time. The medium leaked through the low-temperature end face seal is generally a gas-liquid mixed two-phase medium. Ordinary leather cup seals cannot achieve complete sealing. If the interference is too large, it will easily cause excessive heat generation, resulting in shaft head ablation. In addition, there is currently no special assessment test device for the low-temperature (-196℃) high-speed (speed not less than 20,000rpm) leather cup seal structure, and it is impossible to determine the relationship between the characteristics of the leather cup seal structure and the sealing pressure, and it is impossible to provide accurate technical data support.

[0004] Therefore, in order to overcome the shortcomings of the existing technology, an improved device is provided which can realize two low-temperature end face sealing tests at one time. At the same time, the test device has multiple test functions and can evaluate the sealing structure of gas-liquid two-phase media and the sealing performance of existing leather cups, thereby meeting various test needs and laying the foundation for technical research and engineering applications. Summary of the invention

[0005] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and provide an improved device that can realize two low-temperature end face sealing tests at one time. At the same time, the test device has multiple test functions and can evaluate the sealing structure of gas-liquid two-phase media and the sealing performance of existing leather cups, thereby meeting multiple test requirements and laying the foundation for technical research and engineering applications.

[0006] The solution of the present invention is:

[0007] A multifunctional sealing test device for low temperature, comprising a rotor assembly for transmission, a shell for supporting the rotor assembly and forming a test environment, a product end face sealing assembly, a process end face sealing assembly and a leather cup seal to be tested are symmetrically installed on the rotor assembly and fixed on the shell assembly, respectively; when the three seals are installed at the same time, it is possible to complete the assessment test of two product seals at one time; when only the product end face sealing assembly and the process end face sealing assembly are installed, it is used to assess the sealing ability of the process end face sealing assembly to a gas-liquid two-phase medium; when only the product end face sealing assembly and the leather cup seal are installed, it is used to assess the sealing ability of the leather cup seal to a gas-liquid two-phase medium; when only the leather cup seal is installed, the sealing ability of the leather cup seal to a liquid nitrogen medium can be achieved; when only the process end face sealing assembly is installed, the sealing ability of the process end face sealing assembly to a liquid nitrogen medium can be achieved.

[0008] Preferably, the product end face sealing assembly comprises a front product end face sealing assembly and a rear product end face sealing assembly;

[0009] The flanges of the front product end face sealing assembly and the rear product end face sealing assembly are both installed on the shell by bolts, the static ring end face of the front product end face sealing assembly contacts the front product dynamic ring, and the rear product end face sealing assembly contacts the rear product dynamic ring end face; the structural dimensions of the front product dynamic ring and the rear product dynamic ring are completely consistent.

[0010] Preferably, the installation method of the product end face sealing assembly is as follows: first, the main shaft is connected to the housing through the front low-temperature bearing and the rear low-temperature bearing, and the bearing preload force is adjusted and tightened. The front product sleeve and the front product moving ring are sequentially sleeved on the front end of the main shaft, and are tightened by the front product moving ring clamping nut; the rear product sleeve and the rear product moving ring are sequentially sleeved on the rear end of the main shaft, and are tightened by the rear product moving ring clamping nut; finally, the shaft system is rotated to measure the end face runout of the front and rear product moving rings. If the maximum runout of the end faces of the front and rear product moving rings after one rotation is >0.03mm, the front and rear product moving rings need to be replaced or reassembled; if the maximum runout is ≤0.03mm, the front and rear product moving rings are locked, and the front product end face sealing assembly and the rear product end face sealing assembly are fastened to the housing with bolts.

[0011] Preferably, the compression amount of the front product end face sealing assembly and the rear product end face sealing assembly can be adjusted by using the front product shaft sleeve and the rear product shaft sleeve of different lengths.

[0012] Preferably, the process end face sealing assembly includes a front process end face sealing assembly and a rear process end face sealing assembly; the leather cup seal includes a front leather cup seal and a rear leather cup seal;

[0013] The installation method of the process end face seal assembly and the leather cup seal is as follows:

[0014] On the main shaft, install the front process sleeve and the front process moving ring in sequence at the front end of the front product moving ring, and tighten the front process moving ring through the front process moving ring clamping nut, and install the rear process sleeve and the rear process moving ring in sequence at the rear end of the rear product moving ring, and tighten the rear process moving ring through the rear process moving ring clamping nut; rotate the shaft system to measure the end face runout of the front and rear process moving rings. If the maximum runout of the end faces of the front and rear process moving rings after one rotation is >0.02mm, the front and rear process moving rings need to be replaced or reassembled; if the maximum runout is ≤0.02mm, install the front end cover, the front process end face sealing assembly, the front leather cup seal, and the front pressure cover in sequence at the front end of the shell; install the rear end cover, the rear process end face sealing assembly, the rear leather cup seal, and the rear pressure cover in sequence at the rear end of the shell; the structural dimensions of the front process moving ring and the rear process moving ring are exactly the same.

[0015] Preferably, the compression amounts of the front process end face sealing assembly and the rear process end face sealing assembly are adjusted by front process shaft sleeves and rear process shaft sleeves of different lengths.

[0016] Preferably, the front process end face sealing assembly and the back process end face sealing assembly have the same composition, both comprising a graphite ring, a graphite ring seat, an end face sealing housing, a bellows, and a rear support seat; the graphite ring is installed in the graphite ring seat, the graphite ring seat is fixed on the bellows, the bellows is fixed on the rear support seat, and the rear support seat is fixed on the inner wall of the end face sealing housing;

[0017] After installation, the graphite ring of the front process end face sealing assembly contacts the front process dynamic ring, and the end face sealing housing is fixed on the front end cover; the graphite ring of the rear process end face sealing assembly contacts the rear process dynamic ring, and the end face sealing housing is fixed on the rear end cover; the pressure bearing capacity of the bellows is not less than 0.5MPa.

[0018] Preferably, after the process end face sealing assembly is assembled, its free height is measured, and 4 points are selected on the circumference of the graphite ring end face for measurement, and the maximum free height H1, the minimum free height H2, and the maximum free height difference △Hmax≤0.3mm are recorded. If the maximum free height difference is greater than 0.3mm, the process end face sealing assembly is replaced.

[0019] Preferably, the material of the leather cup seal is F4+graphite, and the fit between the leather cup seal and the main shaft is an interference fit.

[0020] Preferably, the distance between the front cryogenic bearing and the front end face of the main shaft is defined as L1, the distance between the front cryogenic bearing and the rear cryogenic bearing is defined as L2, and the distance between the rear cryogenic bearing and the rear end face of the main shaft is defined as L3;

[0021] The method for determining L2 is: under the premise of satisfying the spatial layout, design L1 and L3 respectively to minimize L1 and L3; then adjust the value of L2 while keeping L1 and L3 at the minimum, calculate the critical speed n of the spindle under each L2 value, and select the distance L2 corresponding to the maximum critical speed n, thereby obtaining the L1, L2, and L3 size values ​​of the spindle.

[0022] Preferably, a process leakage take-over nozzle is installed on the front pressure cover, and a front product leakage take-over nozzle is installed on the front end cover; a front bearing medium inlet take-over nozzle and a front bearing pressure measuring port are provided at the front end of the shell, a rear bearing medium inlet take-over nozzle, a rear bearing pressure measuring port and a rear product leakage take-over nozzle are provided at the rear end of the shell, and a medium discharge port is provided in the middle of the shell; the medium enters the test device from the front bearing medium inlet take-over nozzle and the rear bearing medium inlet take-over nozzle, and discharges from the medium discharge port; the process leakage take-over nozzle, the front product leakage take-over nozzle and the rear product leakage take-over nozzle are used for the discharge of gaseous medium during the test; the front bearing pressure measuring port and the rear bearing pressure measuring port are used for installing pressure sensors to measure the medium pressure entering the bearing.

[0023] The beneficial effects of the present invention compared with the prior art are:

[0024] (1) The test device of the present invention can realize the operation assessment test of two liquid rocket engine turbine pump end face seals at one time, and has the assessment test function for the sealing performance and working performance of the process end face seal + process seal combination seal for gas-liquid two-phase medium and pure liquid low-temperature medium, as well as the assessment test function for the sealing performance and working performance of the leather cup seal for gas-liquid two-phase medium;

[0025] (2) The structural form of the process end face seal + leather cup seal combined seal provided by the present invention can achieve the sealing of the gas-liquid two-phase medium after the product end face seal leaks, improve the sealing performance of the medium after the product leaks at the shaft head, and obtain the accurate value of the leakage amount of the two test products. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of a multifunctional sealing test device;

[0027] Figure 2 It is a partial diagram of the process combination sealing structure;

[0028] Figure 3 This is a working principle diagram of Example 1;

[0029] Figure 4 This is a working principle diagram of Example 2;

[0030] Figure 5 This is a working principle diagram of Example 3. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with the accompanying drawings.

[0032] The main structural components of the disengagement seal test device of the present invention are as follows: Figure 1 As shown, it includes a rotor assembly for transmission, a shell for supporting the rotor assembly and forming a test environment, and three seals, namely, a product end face seal assembly to be tested, a process end face seal assembly and a leather cup seal, are symmetrically installed on the rotor assembly and fixed on the shell assembly. When the three seals are installed at the same time, the assessment test of two product seals can be completed at one time; when only the product end face seal and the process end face seal are installed among the three seals, they are used to assess the sealing ability of the process end face seal for gas-liquid two-phase media; when only the product end face seal and the leather cup seal are installed, they are used to assess the sealing ability of the leather cup seal for gas-liquid two-phase media; when only the leather cup seal is installed, the sealing ability of the leather cup seal for liquid nitrogen medium can be achieved; when only the process end face seal is installed, the sealing ability of the process end face seal for liquid nitrogen medium can be achieved.

[0033] The structural dimensions of the front leather cup seal 3 and the rear leather cup seal 27 , the front process end face seal assembly 4 and the rear process end face seal assembly 26 , and the front product end face seal assembly 9 and the rear product end face seal assembly 21 are completely consistent.

[0034] The flanges of the front product end face sealing assembly 9 and the rear product end face sealing assembly 21 are both installed on the housing 14 by bolts, the static ring end face of the front product end face sealing assembly 9 contacts the front product dynamic ring 10, and the rear product end face sealing assembly 21 contacts the end face of the rear product dynamic ring 20; the structural dimensions of the front product dynamic ring 10 and the rear product dynamic ring 20 are completely consistent. The installation method is as follows: first, connect the main shaft 16 to the housing through the front low-temperature bearing 13 and the rear low-temperature bearing 17, and complete the bearing preload adjustment and tightening. The front product sleeve 12 and the front product dynamic ring 10 are sequentially sleeved on the front end of the main shaft 16, and are tightened by the front product dynamic ring clamping nut 31; the rear product sleeve 18 and the rear product dynamic ring 20 are sequentially sleeved on the rear end of the main shaft 16, and are tightened by the rear product dynamic ring clamping nut 34; finally, rotate the shaft system and measure the end face runout of the front and rear product dynamic rings. If the maximum runout of the end faces of the front and rear product dynamic rings after one rotation is greater than 0.03mm, the front and rear product dynamic rings need to be replaced or reassembled; if the maximum runout is ≤0.03mm, the front and rear product dynamic rings are locked, and the front product end face sealing assembly 9 and the rear product end face sealing assembly 21 are fastened to the housing 14 by bolts.

[0035] The front product shaft sleeve 12 and the rear product shaft sleeve 18 have a series of different sizes, and the compression amount of the front and rear product end face sealing components can be adjusted by different lengths of the front product shaft sleeve 12 and the rear product shaft sleeve 18.

[0036] The process end face sealing assembly includes a front process end face sealing assembly 4 and a rear process end face sealing assembly 26; the leather cup seal 41 includes a front leather cup seal 3 and a rear leather cup seal 27. The front and rear process end face sealing assemblies 4 and 26 are respectively installed on the front end cover 5 and the rear end cover 25 by bolts, and their static ring end faces are respectively in contact with the end faces of the front process dynamic ring 6 and the rear process dynamic ring 24. The structural dimensions of the front process dynamic ring 6 and the rear process dynamic ring 24 are completely consistent, and the installation method is: after completing the installation of the front and rear product end face sealing assemblies, first install the front process sleeve 8 and the front process dynamic ring 6 in sequence at the front end of the front product dynamic ring 10, and tighten the front process dynamic ring 6 through the front process dynamic ring clamping nut 30, and install the rear process sleeve 23 and the rear process dynamic ring 24 in sequence at the rear end of the rear product dynamic ring 20, and press the rear process dynamic ring 24 through the rear process dynamic ring clamping nut 35. Tighten; rotate the shaft system and measure the end face runout of the front and rear process dynamic rings 6 and 24. If the maximum runout of the dynamic ring end face after one rotation is >0.02mm, the dynamic ring needs to be replaced or reassembled; if the maximum runout is ≤0.02mm, after the dynamic ring is tightened, install the front end cover 5, the front process end face seal 4, the front leather cup seal 3, and the front pressure cover 2 at the front end of the device in sequence; install the rear end cover 25, the rear process end face seal 26, the rear leather cup seal 27, and the rear pressure cover 28 at the rear end of the test device in sequence.

[0037] The front process sleeve 8 and the rear process sleeve 23 have a series of different sizes, and the compression amount of the front and rear process end face seals 4 and 26 can be adjusted by the front process sleeve 8 and the rear process sleeve 23 of different lengths.

[0038] The process combined sealing structure formed by the process end face sealing component and the leather cup sealing member is as follows: Figure 2 shown.

[0039] The structural components of the process end face sealing assembly include a graphite ring 36, a graphite ring seat 37, an end face sealing housing 38, a bellows 39, and a rear support seat 40. The graphite ring 36 is installed in the graphite ring seat 37, the graphite ring seat 37 is fixed on the bellows 39, the bellows 39 is fixed on the rear support seat 40, and the rear support seat 40 is fixed on the inner wall of the end face sealing housing 38. The bellows is welded by electron beam welding or pulse argon arc welding, and its pressure bearing capacity is not less than 0.5MPa; the flatness of the graphite ring 36 is not more than 0.6μm, and the height of the boss is not less than 2mm.

[0040] After the process end face seal assembly is assembled, measure its free height, select 4 points on the circumference of the end face of the graphite ring 36 for measurement, record the maximum free height H1, the minimum free height H2, and the maximum free height difference △Hmax≤0.3mm. If the maximum free height difference is greater than 0.3mm, replace the process end face seal assembly.

[0041] After the process end face sealing assembly and the process dynamic ring are assembled together, when the leather cup seal 3 is not installed, 0.3MPa compressed air is introduced from the front product leakage connection nozzle 7 installed on the front end cover, and the leakage amount is detected through the process leakage connection nozzle 1 installed on the front pressure cover 2. The leakage amount should not be greater than 3ml / s.

[0042] The roughness of the working surface of the process dynamic ring 6, 24 in contact with the graphite ring 36 should be no greater than 0.1 μm, and the flatness should be less than 0.6 μm. The surface of the process dynamic ring is sprayed with chromium oxide, and the material of the process dynamic ring is S-07 steel.

[0043] The material of the leather cup seal 41 is F4+graphite, and the fit between the leather cup seal 41 and the main shaft 16 is an interference fit, and the interference is 0.02-0.03 mm; the roughness of the outer cylindrical surface of the main shaft 16 and the leather cup seal 41 is not greater than 0.4 μm.

[0044] Define the distance between the front cryogenic bearing 13 and the front end face of the main shaft 16 as L1, the distance between the front cryogenic bearing 13 and the rear cryogenic bearing 17 as L2, and the distance between the rear cryogenic bearing 17 and the rear end face of the main shaft 16 as L3; then the method for determining L2 is: on the premise of satisfying the spatial layout, design L1 and L3 respectively to minimize L1 and L3; then adjust the value of L2 while keeping L1 and L3 at a minimum, calculate the critical speed n of the main shaft 16 under each L2 value, select the distance L2 corresponding to the maximum critical speed n, and thus obtain the L1, L2, and L3 size values ​​of the main shaft 12.

[0045] A process leakage take-over nozzle 1 is installed on the front pressure cover 2, a front product leakage take-over nozzle 7 is installed on the front end cover 5, a front bearing medium inlet take-over nozzle 32 and a front bearing temperature measuring port 11 are arranged at the front end of the shell 14, a rear bearing medium inlet take-over nozzle 33, a rear bearing temperature measuring port 19 and a rear product leakage take-over nozzle 22 are arranged at the rear end of the shell 14, and a medium discharge port 15 is arranged in the middle of the shell 14; the medium enters the test device from the front bearing medium inlet take-over nozzle 32 and the rear bearing medium inlet take-over nozzle 33, and discharges from the medium discharge port 15; the process leakage take-over nozzle 1, the front product leakage take-over nozzle 7 and the rear product leakage take-over nozzle 22 are used for the discharge of gaseous medium during the test; the front bearing temperature measuring port 11 and the rear bearing temperature measuring port 19 are used for installing pressure sensors to measure the medium pressure entering the bearing.

[0046] Embodiment 1:

[0047] The working principle of the multifunctional sealing test device embodiment 1 is as follows Figure 3As shown, this embodiment can realize the assessment of the sealing performance of the front and rear product end face sealing components 9 and 21 to the low-temperature liquid medium under a specific pressure, and the assessment of the sealing performance of the process end face sealing component and the leather cup seal combination seal to the gas-liquid two-phase medium. Its working principle is that the low-temperature medium enters the front bearing through the low-temperature electric regulating valve, the low-temperature mass flowmeter, and the front bearing medium inlet nozzle 32 installed on the shell, and enters the rear bearing through the low-temperature electric regulating valve, the low-temperature mass flowmeter, and the rear bearing medium inlet nozzle 33 installed on the shell. The cooling flow of the front low-temperature bearing 13 and the rear low-temperature bearing 17 can be adjusted by the low-temperature electric regulating valve. The main shaft 16 is connected to the external driving device through a coupling and rotates at high speed. The pressure sensor is installed through the front bearing pressure measuring nozzle 11 and the rear bearing pressure measuring nozzle 19 to measure the working pressure of the low-temperature medium entering the bearing.

[0048] During operation, the low-temperature medium is converted into a gas-liquid two-phase medium after being sealed by the front product end face sealing component 9 and the rear product end face sealing component 21. The gas-liquid two-phase medium passes through the front product leakage takeover nozzle 7 and the rear product leakage takeover nozzle 22 respectively, and then passes through the vaporizer, the low-temperature stop valve, and the volume flow meter in turn. The leakage amount of the front and rear product end face sealing components is measured by the volume flow meter, and finally the gas medium is discharged into the atmosphere.

[0049] The process leakage takeover nozzle 1 is connected in sequence to a low-temperature stop valve and a volume flow meter, thereby judging the sealing ability of the front process end face sealing component 4 and the front leather cup seal 3 of the process combined sealing structure to the gas-liquid two-phase medium.

[0050] Embodiment 2:

[0051] The working principle of the multifunctional sealing test device embodiment 2 is as follows Figure 4 As shown, this embodiment can realize the assessment of the sealing performance of the front and rear product end face sealing components 9 and 21 to the low-temperature liquid medium under a specific pressure, and the assessment of the sealing performance of the leather cup seal to the gas-liquid two-phase medium. The difference between it and Example 1 is that the front and rear process end face sealing components 4 and 26 are not installed, and the low-temperature stop valve and the volume flow meter are connected in sequence after the process leakage connection nozzle 1 to assess the sealing ability of the front leather cup seal 3 to the gas-liquid two-phase medium.

[0052] During operation, the low-temperature medium is converted into a gas-liquid two-phase medium after being sealed by the front product end face sealing component 9 and the rear product end face sealing component 21. The gas-liquid two-phase medium passes through the front product leakage take-over nozzle 7 and the rear product leakage take-over nozzle 22 respectively, and then passes through the vaporizer, the low-temperature stop valve, and the volume flow meter in turn. The leakage amount of the front and rear product end face sealing components is measured by the volume flow meter, and finally the gas medium is discharged into the atmosphere.

[0053] Embodiment 3:

[0054] The working principle of the multifunctional sealing test device embodiment 3 is as follows Figure 5 The difference between the embodiment 1 and the embodiment 1 is that the front and rear product end face sealing components 9 and 21 are not installed, and the front product leakage nozzle 7 and the rear product leakage nozzle 22 of the test device are blocked to assess the sealing performance of the process end face sealing component and the leather cup seal combination to the low-temperature liquid medium under a specific pressure.

[0055] The process leakage takeover nozzle 1 is connected to the vaporizer, low-temperature stop valve and volume flow meter in sequence, thereby judging the sealing ability of the process end face sealing component 4 and the front leather cup seal 3 of the process combined sealing structure to the gas-liquid two-phase medium.

[0056] The invention realizes multifunctional testing of low-temperature and high-speed end face sealing of a liquid rocket engine turbo pump and process end face sealing and low-temperature leather cup sealing of a testing device.

[0057] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A multifunctional sealing test device for low temperature, characterized in that: It includes a rotor assembly for transmission, a shell for supporting the rotor assembly and forming a test environment. The product end face sealing assembly, process end face sealing assembly and leather cup seal to be tested are symmetrically installed on the rotor assembly and fixed on the shell assembly respectively. When the three seals are installed at the same time, the assessment test of two product seals can be completed at one time; when only the product end face sealing assembly and the process end face sealing assembly are installed, it is used to assess the sealing ability of the process end face sealing assembly for gas-liquid two-phase media; when only the product end face sealing assembly and the leather cup seal are installed, it is used to assess the sealing ability of the leather cup seal for gas-liquid two-phase media; when only the leather cup seal is installed, the sealing ability of the leather cup seal for liquid nitrogen medium can be achieved; when only the process end face sealing assembly is installed, the sealing ability of the process end face sealing assembly for liquid nitrogen medium can be achieved.

2. A multifunctional sealing test device for low temperature use according to claim 1, characterized in that: The product end face sealing assembly comprises a front product end face sealing assembly (9) and a rear product end face sealing assembly (21); The flanges of the front product end face sealing assembly (9) and the rear product end face sealing assembly (21) are both mounted on the housing (14) by means of bolts; the static ring end face of the front product end face sealing assembly (9) contacts the front product dynamic ring (10), and the rear product end face sealing assembly (21) contacts the end face of the rear product dynamic ring (20); the structural dimensions of the front product dynamic ring (10) and the rear product dynamic ring (20) are completely consistent.

3. A multifunctional sealing test device for low temperature use according to claim 2, characterized in that: The method for installing the product end face seal assembly is as follows: firstly, the main shaft (16) is connected to the housing through the front low-temperature bearing (13) and the rear low-temperature bearing (17), and the bearing preload is adjusted and tightened; the front product shaft sleeve (12) and the front product dynamic ring (10) are sequentially sleeved on the front end of the main shaft (16), and are tightened by the front product dynamic ring clamping nut (31); the rear product shaft sleeve (18) and the rear product dynamic ring (20) are sequentially sleeved on the rear end of the main shaft (16), and are tightened by the rear product dynamic ring clamping nut (34); finally, the shaft system is rotated to measure the end face runout of the front and rear product dynamic rings; if the maximum runout of the end faces of the front and rear product dynamic rings after one rotation is greater than 0.03 mm, the front and rear product dynamic rings need to be replaced or reassembled; if the maximum runout is less than or equal to 0.03 mm, the front and rear product dynamic rings are locked, and the front product end face seal assembly (9) and the rear product end face seal assembly (21) are tightened to the housing (14) through bolts.

4. A multifunctional sealing test device for low temperature use according to claim 3, characterized in that: The compression amounts of the front product end face sealing assembly (9) and the rear product end face sealing assembly (21) can be adjusted by using the front product shaft sleeve (12) and the rear product shaft sleeve (18) of different lengths.

5. The multifunctional sealing test device for low temperature use according to claim 3, characterized in that: The process end face sealing assembly comprises a front process end face sealing assembly (4) and a rear process end face sealing assembly (26); the leather cup sealing member (41) comprises a front leather cup sealing member (3) and a rear leather cup sealing member (27); The installation method of the process end face seal assembly and the leather cup seal is as follows: On the main shaft, a front process sleeve (8) and a front process movable ring (6) are sequentially installed at the front end of the front product movable ring (10), and the front process movable ring (6) is compressed by a front process movable ring clamping nut (30); a rear process sleeve (23) and a rear process movable ring (24) are sequentially installed at the rear end of the rear product movable ring (20), and the rear process movable ring (24) is compressed by a rear process movable ring clamping nut (35); the shaft system is rotated to measure the end face runout of the front and rear process movable rings; if the end faces of the front and rear process movable rings are rotated by one degree, the end faces of the front and rear process movable rings are If the maximum runout of the ring is greater than 0.02mm, the front and rear process dynamic rings need to be replaced or reassembled; if the maximum runout is ≤0.02mm, the front cover (5), the front process end face sealing assembly (4), the front leather cup seal (3), and the front pressure cover (2) are installed in sequence at the front end of the shell; the rear cover (25), the rear process end face sealing assembly (26), the rear leather cup seal (27), and the rear pressure cover (28) are installed in sequence at the rear end of the shell; the structural dimensions of the front process dynamic ring (6) and the rear process dynamic ring (24) are completely consistent.

6. A multifunctional sealing test device for low temperature use according to claim 5, characterized in that: The compression amounts of the front process end face sealing component (4) and the rear process end face sealing component (26) are adjusted by using the front process shaft sleeve (8) and the rear process shaft sleeve (23) of different lengths.

7. A multifunctional sealing test device for low temperature use according to claim 5, characterized in that: The front process end face sealing assembly (4) and the rear process end face sealing assembly (26) have the same composition, and both include a graphite ring (36), a graphite ring seat (37), an end face sealing housing (38), a bellows (39), and a rear support seat (40); the graphite ring (36) is installed in the graphite ring seat (37), the graphite ring seat (37) is fixed on the bellows (39), the bellows (39) is fixed on the rear support seat (40), and the rear support seat (40) is fixed on the inner wall of the end face sealing housing (38); After installation, the graphite ring of the front process end face sealing assembly contacts the front process dynamic ring, and the end face sealing housing is fixed on the front end cover; the graphite ring of the rear process end face sealing assembly contacts the rear process dynamic ring, and the end face sealing housing is fixed on the rear end cover; the pressure bearing capacity of the bellows is not less than 0.5MPa.

8. A multifunctional sealing test device for low temperature use according to claim 7, characterized in that: After the process end face sealing assembly is assembled, its free height is measured, and 4 points are selected on the circumference of the end face of the graphite ring (36) for measurement, and the maximum free height H1, the minimum free height H2, and the maximum free height difference △Hmax≤0.3mm are recorded. If the maximum free height difference is greater than 0.3mm, the process end face sealing assembly is replaced.

9. The multifunctional sealing test device for low temperature use according to claim 7, characterized in that: The material of the leather cup seal (41) is F4+graphite, and the fit between the leather cup seal (41) and the main shaft is an interference fit.

10. The multifunctional sealing test device for low temperature use according to claim 2, characterized in that: The distance between the front cryogenic bearing (13) and the front end surface of the main shaft (16) is defined as L1, the distance between the front cryogenic bearing (13) and the rear cryogenic bearing (17) is defined as L2, and the distance between the rear cryogenic bearing (17) and the rear end surface of the main shaft (16) is defined as L3; The method for determining L2 is as follows: on the premise of satisfying the spatial layout, L1 and L3 are designed respectively to minimize L1 and L3; then, while keeping L1 and L3 at a minimum, the value of L2 is adjusted, and the critical speed n of the main shaft (16) is calculated under each L2 value, and the distance L2 corresponding to the maximum critical speed n is selected, thereby obtaining the L1, L2, and L3 size values ​​of the main shaft (12).

11. The multifunctional sealing test device for low temperature use according to claim 7, characterized in that: A process leakage take-over nozzle (1) is installed on the front pressure cover (2), a front product leakage take-over nozzle (7) is installed on the front end cover (5), a front bearing medium inlet take-over nozzle (32) and a front bearing pressure measuring port (11) are arranged at the front end of the housing (14), a rear bearing medium inlet take-over nozzle (33), a rear bearing pressure measuring port (19), and a rear product leakage take-over nozzle (22) are arranged at the rear end of the housing (14), and a medium discharge port (15) is arranged in the middle of the housing (14); the medium enters the test device from the front bearing medium inlet take-over nozzle (32) and the rear bearing medium inlet take-over nozzle (33), and is discharged from the medium discharge port (15); the process leakage take-over nozzle (1), the front product leakage take-over nozzle (7), and the rear product leakage take-over nozzle (22) are used for discharging gaseous medium during the test process; the front bearing pressure measuring port (11) and the rear bearing pressure measuring port (19) are used for installing pressure sensors to measure the pressure of the medium entering the bearing.

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