Liquid argon filling device and method

Abstract

This invention discloses a liquid argon filling device and method, relating to the technical field of liquid filling. It includes a liquid argon pump with a plurality of rotor tooth grooves on its pump shaft and a plurality of stator tooth grooves on its end cover. The stator tooth grooves cooperate with the pump shaft surface to form a labyrinth seal structure. The device further includes: an inlet ring groove located on the end cover and externally connected to a high-purity argon gas source; a return ring groove located on the end cover and externally connected to an argon gas recovery device; and a control system for controlling the operating modes of the liquid argon pump. The operating modes of the liquid argon pump include: a liquid argon filling mode, where a high-purity argon gas source delivers argon gas into the labyrinth seal structure through the inlet ring groove, while the argon gas recovery device recovers argon gas through the return ring groove, and the argon gas flows within the labyrinth seal structure to form a dynamic sealing barrier; and a standby idle mode, where, after filling, the control system controls the liquid argon pump to operate at a low speed, and high-purity argon gas is continuously supplied to maintain the dynamic sealing barrier.

Description

Technical Field

[0001] This invention relates to the field of liquid filling technology, specifically to a liquid argon filling device and method. Background Technology

[0002] As is generally known, liquid argon is the liquid form of argon gas, a colorless, odorless, tasteless, and non-toxic inert gas. Argon is typically extracted using air separation, specifically by distilling liquefied air to produce crude argon. This crude argon is then further purified to obtain high-purity argon. It is widely used in stainless steel smelting, precision welding, semiconductor manufacturing, medical cryogenics, and scientific research. Its storage and transportation typically employ cryogenic technology, where argon gas is liquefied and stored in an insulated tank at -186°C. It is then pressurized and transported via a filling device to tank trucks or Dewar flasks.

[0003] The liquid argon pumps used in the filling system to transport liquid argon are mainly fixed-frequency centrifugal or piston pumps. Centrifugal pumps are the preferred choice due to their advantages such as large flow rate, stable operation, and easy maintenance. A typical structure consists of a pump body, main shaft, bearings, sealing components, a motor, and a vacuum-insulated cold box. During operation, the motor drives the impeller to rotate at high speed. The liquid argon gains kinetic energy under centrifugal force and is converted into pressure energy by a diffuser to achieve pressurized delivery. Regarding sealing technology, existing liquid argon pumps generally use labyrinth seals (ordinary labyrinth seals rely on precisely machined tooth grooves to create fluid resistance and prevent media leakage) or mechanical seals (mechanical seals achieve sealing through the tight fit between the rotating and stationary rings).

[0004] However, when labyrinth seals are running statically or at low speeds, moisture can easily accumulate and freeze within the sealing gaps, especially in high-humidity environments. Once frozen, this can lead to shaft jamming, increased vibration, seal failure, and even shutdown accidents. Therefore, existing liquid argon pumps cannot achieve a standby mode of "long-term pressure holding + low-flow circulation". It can be seen that existing sealing technologies cannot achieve stable and long-term gas-liquid isolation and anti-icing functions under low-temperature, humid, and dynamic operating conditions. There is a lack of a sealing solution that can operate continuously under low-load conditions without freezing or leakage. Summary of the Invention

[0005] The purpose of this invention is to provide a liquid argon filling device and method to solve the technical problems in related technologies.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A liquid argon filling device includes a liquid argon pump. The pump shaft of the liquid argon pump has several rotor tooth grooves, and the end cover of the liquid argon pump has several stator tooth grooves. The stator tooth grooves cooperate with the surface of the pump shaft to form a labyrinth seal structure. The device also includes: an inlet ring groove located on the end cover and externally connected to a high-purity argon gas source; a return ring groove located on the end cover and externally connected to an argon gas recovery device; and a control system for controlling the operating modes of the liquid argon pump. The operating modes of the liquid argon pump include: a liquid argon filling mode, where a high-purity argon gas source delivers argon gas into the labyrinth seal structure through the inlet ring groove, while the argon gas recovery device recovers argon gas through the return ring groove, and the argon gas flows within the labyrinth seal structure to form a dynamic sealing barrier; and a standby coasting mode, where, after filling is completed, the control system controls the liquid argon pump to operate at a low speed, and high-purity argon gas is continuously supplied to maintain the dynamic sealing barrier.

[0008] As mentioned above, the air inlet ring groove is arranged in the middle of several stator tooth grooves, and several air outlet holes are opened on both sides of its end facing the pump shaft. In a unit time, the air output of several air outlet holes is less than the air filling volume of high-purity argon gas source into the air inlet ring groove.

[0009] As mentioned above, there are two return air ring grooves, which are arranged on both sides of several stator tooth grooves. Several air inlet holes are opened at the ends of the return air ring grooves facing the pump shaft, and the diameter of the air inlet holes is smaller than the diameter of the air outlet holes.

[0010] As described above, the stator tooth groove includes a stator base fixed to the end cover and a plurality of stator tooth rings arranged sequentially on the stator base, the portion between two adjacent stator tooth rings being the stator tooth groove; the stator tooth ring is divided into several segments on the shaft, with adjacent segments in sliding contact, each segment of the stator tooth ring is slidably arranged on the stator base, and in the sliding direction, a first elastic element is provided between each segment of the stator tooth ring and the stator base.

[0011] As described above, each segment of the stator gear ring has a slot at one end and an insert at the other end, and the slot and insert between two adjacent segments of the stator gear ring are connected by a convex-concave fit.

[0012] As mentioned above, the cross-section of the stator gear ring is trapezoidal, and the width of the side facing the pump shaft is smaller than the width of the side contacting the stator base.

[0013] As described above, a first electromagnet is installed on the stator base at a position corresponding to each segment of the stator gear ring, and a second electromagnet is installed on each segment of the stator gear ring. The distance between the stator gear ring and the rotor tooth slot is controlled based on the magnetic force between the first electromagnet and the second electromagnet.

[0014] As described above, the pump shaft is provided with rotor tooth slots, the rotor tooth slots include a rotor base fixed to the pump shaft, and a plurality of rotor tooth rings arranged sequentially on the rotor base, the plurality of stator tooth rings and the plurality of rotor tooth rings being arranged alternately.

[0015] As mentioned above, the rotor gear ring has a trapezoidal cross-section, and its orientation is opposite to that of the stator gear ring.

[0016] This invention also relates to a liquid argon filling method, which includes the following steps when filling liquid argon using the aforementioned liquid argon filling device:

[0017] Step 1: Liquid argon filling. The control system receives the filling command, controls the liquid argon pump to rotate, and simultaneously controls the high-purity argon gas source to input argon gas into the labyrinth sealing structure. When the liquid argon pump speed increases to the rated value, the argon gas flows in the labyrinth sealing structure to form a dynamic sealing barrier, and the liquid argon begins to be delivered.

[0018] Step 2: Standby coasting. Liquid argon filling is completed. The control system controls the liquid argon pump to run at low speed, and high-purity argon gas is continuously supplied to maintain the dynamic sealing barrier. The filling device is in a pressure-holding standby state.

[0019] Step 3: Rapid Response Start-up. When the next filling command is transmitted to the control system, the control system controls the liquid argon pump to directly increase its speed to the rated speed, and the liquid argon filling operation can be carried out directly.

[0020] The beneficial effects of this invention are as follows: by continuously flowing high-purity argon gas within the labyrinth sealing structure to form a dynamic sealing barrier, a standby mode with long-term pressure maintenance and low-flow circulation can be achieved during the standby coasting phase. When filling with liquid argon, it can quickly respond to commands. Thus, the liquid argon pump maintains effective sealing and isolation from the outside world regardless of whether it is in operation, thereby better ensuring that the liquid argon pump can continue to operate under low-load conditions without freezing or leakage problems. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0022] Figure 1 A three-dimensional structural schematic diagram of a liquid argon pump for a liquid argon filling device provided by the present invention;

[0023] Figure 2 A three-dimensional structural diagram of the stator gear ring and rotor gear ring of a liquid argon filling device provided by the present invention;

[0024] Figure 3 A schematic diagram of the axial planar structure of a liquid argon pump for a liquid argon filling device provided by the present invention;

[0025] Figure 4 for Figure 3 A schematic diagram of the cross-sectional structure at point AA;

[0026] Figure 5 for Figure 4 Enlarged structural diagram at point B in the diagram;

[0027] Figure 6 A schematic diagram of the radial planar structure of a liquid argon filling device provided by the present invention when the stator tooth groove and rotor tooth groove are engaged.

[0028] Figure 7 for Figure 3 A schematic diagram of the cross-sectional structure at point CC.

[0029] Explanation of reference numerals in the attached figures:

[0030] 1. Liquid argon pump; 10. Pump shaft; 11. End cover; 12. Motor; 2. Stator tooth groove; 20. Stator base; 21. Stator gear ring; 22. First elastic element; 23. Slot; 24. Insert block; 25. First electromagnet; 26. Second electromagnet; 3. Inlet ring groove; 30. Outlet port; 4. Return ring groove; 40. Inlet port; 5. Rotor tooth groove; 50. Rotor base; 51. Rotor gear ring; 52. Limiting block; 53. Trigger rod; 54. Extrusion groove; 55. Second elastic element. Detailed Implementation

[0031] To enable those skilled in the art to better understand the technical solution of the present invention, the following will be described in conjunction with the appendix. Figure 1 To be continued Figure 7 The present invention will now be described in further detail.

[0032] One embodiment of the present invention relates to a liquid argon filling device, including a liquid argon pump 1. The pump shaft 10 of the liquid argon pump 1 is provided with a plurality of rotor tooth grooves 5, and the end cover 11 of the liquid argon pump 1 is provided with a plurality of stator tooth grooves 2. The plurality of stator tooth grooves 2 cooperate with the surface of the pump shaft 10 to form a labyrinth seal structure. The device also includes: an inlet ring groove 3, which is provided on the end cover 11 and externally connected to a high-purity argon gas source; a return ring groove 4, which is provided on the end cover 11 and externally connected to an argon gas recovery device; and a control system, which is used to control the working mode of the liquid argon pump 1. The working modes of the liquid argon pump 1 include: a liquid argon filling mode, in which the liquid argon pump 1 delivers liquid argon, and the high-purity argon gas source delivers argon gas into the labyrinth seal structure through the inlet ring groove 3, while the argon gas recovery device recovers argon gas through the return ring groove 4, and the argon gas flows in the labyrinth seal structure to form a dynamic sealing barrier; and a standby coasting mode, in which the control system controls the liquid argon pump 1 to run at a low speed after filling is completed, and the high-purity argon gas is continuously supplied to maintain the dynamic sealing barrier.

[0033] Specifically, the liquid argon pump 1 is preferably a horizontal single-stage centrifugal pump made of low-temperature austenitic stainless steel. It includes a suction chamber, impeller, pump shaft 10, guide vanes, and a volute discharge chamber. The designed outlet pressure is 0.5 to 0.7 MPa, with the rated flow rate configured according to filling requirements. One end of the pump shaft 10 extends from the end cover 11 of the liquid argon pump 1 and is connected to the drive system via a flexible coupling. A bearing is provided between the pump shaft 10 and the end cover 11. The drive system uses an explosion-proof variable frequency motor 12 with a power range of 30 to 75 kW, supporting soft start, speed control, and overload protection. A sealing system is arranged at the corresponding part of the pump shaft 10 and the end cover 11, specifically, a number of stator grooves 2 are arranged on the side of the end cover 11 facing the pump shaft 10. These stator grooves 2 are arranged sequentially along the axial direction of the pump shaft 10, and a considerable number of them are... At stage 5, several stator grooves 2 cooperate with the surface of the pump shaft 10 to form a labyrinth seal structure. During the outward leakage of fluid, the labyrinth seal structure can create resistance to the fluid. That is, during the flow of fluid, due to the sudden expansion and contraction throttling effect of each stage of stator grooves 2, the fluid velocity increases suddenly and the pressure drops suddenly when passing through the gap of stator grooves 2, causing the fluid pressure to gradually decrease. Reasonable control of the gap can effectively increase the fluid resistance and reduce the leakage. That is, in this embodiment, the gap is controlled between 0.1 and 0.3 mm (in the "gap flow" law of fluid mechanics, the leakage is proportional to the cube of the gap width). The control system is used to receive the filling command and control the opening and closing of the drive system and the opening and closing of each valve according to the filling command, thereby realizing the filling of liquid argon.

[0034] However, in existing technologies, when the labyrinth seal structure is running statically or at low speed, moisture tends to accumulate and freeze in the sealing gap, especially in environments with high humidity. Once frozen, it can cause shaft jamming, increased vibration, seal failure, and even shutdown accidents. Therefore, the existing liquid argon pump 1 cannot achieve the standby mode of "long-term pressure holding + small flow circulation". It can be seen that the existing sealing technology cannot achieve stable and long-term gas-liquid isolation and anti-icing functions under low temperature, humid, and dynamic operating conditions.

[0035] Based on the aforementioned technical problems, this embodiment provides a sealing solution that can operate continuously under low load conditions without freezing or leakage. Specifically, an inlet ring groove 3 and a return ring groove 4 are arranged on the end cover 11. The inlet ring groove 3 is connected to a high-purity argon gas source. The high-purity argon gas supplied by the high-purity argon gas source is generated after liquid argon has undergone heat exchange and vaporization with air through a coil heat exchanger, with the coil heat exchanger located to one side of the liquid argon pump. The return ring groove 4 is connected to an argon gas recovery device. The high-purity argon gas source can continuously supply high-purity argon gas to the labyrinth seal structure after adjusting the pressure to 0.3 to 0.5 MPa via a pressure reducing valve. Then, the argon gas recovery device can recover the argon gas within the labyrinth seal structure. In this way, the argon gas will be continuously supplied to the labyrinth seal. The structure forms a dynamic sealing barrier through flow within it. A differential pressure transmitter is also installed to monitor the pressure difference between the labyrinth seal structure and the pump chamber in real time. The preferred pressure difference is maintained between 0.1 and 0.2 MPa to ensure a positive pressure sealing barrier. Temperature sensors and dew point meters can also be added to monitor the humidity and icing risk in the sealed area. Automatic pressure-maintaining valve groups are also installed at the inlet and outlet of the liquid argon pump 1, which, together with the pressure transmitter, maintain the pressure in the pump chamber within a safe range of 0.2 to 0.4 MPa. In case of overpressure, the pressure relief valve is automatically opened. The control system is an automated control unit based on PLC, which integrates signals such as temperature, pressure, flow rate, and valve status to control the switching of the working mode of the liquid argon pump 1.

[0036] The specific work process is as follows:

[0037] Filling stage: When the control system receives the filling command, the PLC closes the reflux regulating valve, gradually increases the motor speed to the rated value, opens the filling shut-off valve, and begins to deliver liquid argon to the tank truck;

[0038] Standby coasting stage: After filling is completed, close the filling valve and open the reflux valve. Liquid argon pump 1 reduces its speed to a low speed and maintains the minimum reflux flow rate. The liquid argon pump 1 maintains a low-temperature liquid environment inside with stable pressure. It does not need to be emptied or depressurized and is in a "cold standby" state.

[0039] Quick-response start-up: When the next filling task arrives, the system directly accelerates to the working speed, opens the filling valve, and can be put into operation immediately without pre-cooling;

[0040] Anomaly Handling Mechanism: When abnormal pressure difference, excessively high / low bearing temperature, or excessive vibration is detected, the system will automatically alarm and execute a safety shutdown procedure.

[0041] This embodiment forms a dynamic sealing barrier by continuously flowing high-purity argon gas within the labyrinth sealing structure. During the idle coasting phase, it can achieve a standby mode with long-term pressure maintenance and low-flow circulation. When filling with liquid argon, it can quickly respond to commands. In this way, the liquid argon pump 1 maintains effective sealing and isolation from the outside world regardless of whether it is in operation, thereby better ensuring that the liquid argon pump 1 can continue to operate under low-load conditions without freezing or leakage problems.

[0042] Preferably, the inlet ring groove 3 is arranged in the middle of several stator tooth grooves 2, and several outlet holes 30 are opened on both sides of its end facing the pump shaft 10. In a unit time, the gas output of the several outlet holes 30 is less than the gas output of the high-purity argon source into the inlet ring groove 3. There are two return ring grooves 4, which are arranged on both sides of several stator tooth grooves 2. Several inlet holes 40 are opened on the end of the return ring groove 4 facing the pump shaft 10, and the diameter of the inlet holes 40 is smaller than the diameter of the outlet holes 30.

[0043] Specifically, for the sealing of the liquid argon pump 1, it is necessary not only to prevent the fluid inside the pump chamber from leaking outwards, but also to prevent external gases and impurities from entering the pump chamber. Therefore, in this embodiment, the inlet ring groove 3 is arranged in the middle of several stator tooth grooves 2, that is, high-purity argon gas is input from the middle of the labyrinth seal structure. Two return ring grooves 4 are arranged, located at both ends of the axial direction of the labyrinth seal structure. In this way, high-purity argon gas flows from the middle of the labyrinth seal structure to both ends, and simultaneously provides dynamic sealing for both the pump chamber side and the outer side. To ensure that the argon gas can fill the entire labyrinth seal structure relatively evenly and avoid sealing dead corners, several outlet holes 30 are opened on both sides of the inlet ring groove 3. During the specified time, the outflow rate of several vent holes 30 is less than the inflow rate of high-purity argon gas into the inlet ring groove 3. As a result, the high-purity argon gas will basically keep filling the inlet ring groove 3. Then, this argon gas enters the labyrinth sealing structure from several vent holes 30 at the same time. However, the outflow rate is not as large as the inflow rate, so each vent hole 30 will discharge argon gas. This allows the argon gas to better fill the entire sealing structure. Moreover, the diameter of several inlet holes 40 arranged on the return ring groove 4 is smaller than the diameter of several vent holes 30. Therefore, the argon gas in the labyrinth sealing structure will not be quickly recovered. That is, the internal pressure of the labyrinth sealing structure is greater than the pressure in the return ring groove 4, thus achieving the effect of sealing and isolation.

[0044] Furthermore, the stator tooth groove 2 includes a stator base 20 fixed to the end cover 11 and a plurality of stator tooth rings 21 arranged sequentially on the stator base 20, the portion between two adjacent stator tooth rings 21 being the stator tooth groove 2; the stator tooth ring 21 is divided into several segments in the circumferential direction, with adjacent segments in sliding contact, each segment of the stator tooth ring 21 is slidably arranged on the stator base 20, and in the sliding direction, each segment of the stator tooth ring 21 is provided with a first elastic element 22 between it and the stator base 20.

[0045] Specifically, in the aforementioned embodiments, the gap is controlled between 0.1 and 0.3 mm. However, during the operation of the liquid argon pump 1, the gap will increase due to thermal expansion and contraction (contraction at low temperatures and expansion during high-speed operation) and shaft wear, resulting in a decrease in the sealing effect. Therefore, to solve this problem, in this embodiment, the stator tooth groove 2 is composed of a stator base 20 fixed to the end cover 11 and several stator tooth rings 21 arranged axially on the stator base 20. The stator tooth groove 2 is the space between two adjacent stator tooth rings 21. Each stator tooth ring 21 is then divided into equal parts. Each segment of the stator tooth ring 21 is slidably arranged on the stator base 20, with the sliding direction parallel to the radial direction corresponding to that segment. A first elastic element 22 is provided between each segment of the stator tooth ring 21 and the stator base 20. The first elastic element 22 is made of a low-temperature resistant alloy. The elastic force of the first elastic element 22 pushes each segment of the stator tooth ring 21 closer to the pump shaft 10 when the gap increases. This maintains the gap between 0.1 and 0.3 mm. In a preferred embodiment, each segment of the stator gear ring 21 has a slot 23 at one end and a plug 24 at the other end. The slot 23 and plug 24 between adjacent segments of the stator gear ring 21 are engaged by a convex-concave fit. This allows adjacent segments of the stator gear ring 21 to slide freely in their respective sliding directions without affecting each other. Furthermore, the argon gas will not pass directly between adjacent segments of the stator gear ring 21 along the axial flow path, ensuring that the argon gas flows along a predetermined route and thus guaranteeing sealing performance. In an optional embodiment, the cross-section of the stator gear ring 21 is trapezoidal, with the width on the side facing the pump shaft 10 being smaller than the width on the side contacting the stator base 20. This trapezoidal structure can enhance the rigidity of the tooth root of the stator gear ring 21, preventing brittle fracture at low temperatures. The small contact area between the tooth tip of the stator gear ring 21 and the pump shaft 10 reduces frictional resistance. At the same time, the inclined surface of the trapezoidal structure can guide the airflow and improve the throttling effect.

[0046] Furthermore, a first electromagnet 25 is installed on the stator base 20 at a position corresponding to each segment of the stator gear ring 21, and a second electromagnet 26 is installed on each segment of the stator gear ring 21. Based on the magnetic force between the first electromagnet 25 and the second electromagnet 26, the distance between the stator gear ring 21 and the rotor tooth groove 5 is controlled.

[0047] Specifically, the sealing gap of the labyrinth seal structure should change with the operating conditions. That is, by utilizing the magnetic force between the first electromagnet 25 and the second electromagnet 26, combined with the elastic force of the first elastic element 22, the magnetic force and the elastic force are in opposite directions. The magnetic force tends to drive the stator gear ring 21 away from the pump shaft 10, while the elastic force tends to push the stator gear ring 21 closer to the pump shaft 10. When the magnetic force is greater than the elastic force, the stator gear ring 21 moves away from the pump shaft 10. When the magnetic force and the elastic force reach a balance, the position of the stator gear ring 21 is fixed. When the magnetic force is less than the elastic force, the stator gear ring 21 moves closer to the pump shaft 10. In this way, the gap distance can be precisely adjusted, which can avoid friction and jamming caused by the gap being too small, and also prevent the sealing performance from decreasing due to the gap being too large.

[0048] Preferably, the pump shaft 10 is provided with rotor tooth grooves 5, the rotor tooth grooves 5 include a rotor base 50 fixed to the pump shaft 10, and a plurality of rotor tooth rings 51 arranged sequentially on the rotor base 50, and a plurality of stator tooth rings 21 and a plurality of rotor tooth rings 51 are arranged alternately; the cross section of the rotor tooth rings 51 is trapezoidal, and its orientation is opposite to that of the stator tooth rings 21.

[0049] Specifically, in the aforementioned embodiments, a labyrinth seal structure formed by the mating of several stator slots 2 with the surface of the pump shaft 10 achieves a dynamic sealing effect when argon gas flows through the labyrinth seal structure. Each stage of stator slots 2 achieves one throttling, and the pressure attenuation depends on the increase in the number of stator slots 2. In this embodiment, to further improve the throttling effect and enhance the sealing performance, several rotor slots 5 are arranged on the pump shaft 10. The rotor slots 5 consist of a rotor base 50 fixed to the pump shaft 10 and several rotor teeth arranged sequentially on the rotor base 50. Composed of rings 51, several stator gear rings 21 and several rotor gear rings 51 are arranged alternately in the axial direction to form a labyrinth seal structure. The flow path of argon gas is similar to an S-shape. Argon gas can achieve two throttlings after passing through each stage of stator gear slot 2. In the same space, a significant pressure reduction can be achieved without increasing the number of stator gear slots 2. In this embodiment, by setting several rotor gear slots 5 and several stator gear slots 2 to cooperate, the liquid argon pump 1 can achieve the effects of low-load coasting without freezing, high-load operation without leakage, and high long-term operational reliability.

[0050] During the operation of the liquid argon pump 1, sudden radial runout and axial movement occur. When these two situations are significant, rigid collisions can occur, leading to damage to the liquid argon pump 1. In the aforementioned embodiment, the stator gear ring 21 is arranged in a split configuration and can slide along its respective radial direction. When the pump shaft 10 experiences radial runout, the rotor tooth groove 5 impacts the stator gear ring 21, which can be buffered by the elastic force of the first elastic element 22, thus providing protection. However, this structure cannot protect the rotor gear ring 51 from impacting the stator gear ring 21 when the pump shaft 10 experiences axial movement. Therefore, in the optional embodiment... The rotor gear ring 51 is axially slidably arranged on the rotor base 50. A limit block 52 is provided at its sliding position. The limit block 52 is slidably arranged on the corresponding rotor gear ring 51, and its sliding direction is perpendicular to the sliding direction of the rotor gear ring 51 on the rotor base 50. A trigger rod 53 is axially slidably arranged on the rotor base 50. The distance between the end of the trigger rod 53 and the end cover 11 is less than the distance between the adjacent stator gear ring 21 and the rotor gear ring 51. A second elastic element 55 is installed on the trigger rod 53. The limit block 52 is fixedly connected to the second elastic element 55. A plurality of extrusion grooves 54 are formed on the trigger rod 53. The pressing groove 54 corresponds to and is inserted into several limiting blocks 52 one by one. During normal operation, based on the elastic force of the second elastic element 55, the distance between the two ends of the trigger rod 53 and the end cover 11 remains consistent, and the pressing groove 54 is normally inserted into the corresponding limiting block 52, thus restricting the axial movement of the rotor gear ring 51. When either end of the trigger rod 53 is pressed by the end cover 11 (due to excessive axial movement of the pump shaft 10), the trigger rod 53 drives the pressing groove 54 to exert a pressing effect on the corresponding limiting block 52 (the wedge-shaped fit between the two achieves the pressing action). When the limiting block 52 disengages from the corresponding pressing groove 54, the rotor gear ring 51... When the axial movement restriction of groove 5 is released, it can squeeze the second elastic element 55 axially when it impacts the stator gear ring 21. The elastic force of the second elastic element 55 buffers the impact force and plays a protective role. When the squeezing groove 54 squeezes the limiting block 52 out of the insertion, the limiting block 52 will also drive the second elastic element 55 to produce radial elastic deformation. That is, after the axial movement of the pump shaft 10 disappears, the elastic force of the second elastic element 55 will make the distance between the two ends of the trigger rod 53 and the end cover 11 basically consistent again. The limiting block 52 will also re-insert into the corresponding squeezing groove 54, and the rotor gear ring 51 will be reset and its position will be restricted again.

[0051] In summary, it can be seen that the radial sliding of the stator gear ring 21 is used to protect the pump shaft 10 when it experiences large radial runout, and the axial sliding of the rotor gear ring 51 is used to protect the pump shaft 10 when it experiences large axial runout.

[0052] Another embodiment of the present invention also relates to a liquid argon filling method, which includes the following steps when filling liquid argon using the liquid argon filling device described above:

[0053] Step 1: Liquid argon filling. The control system receives the filling command and controls the liquid argon pump 1 to rotate. At the same time, it controls the high-purity argon gas source to input argon gas into the labyrinth sealing structure. When the speed of the liquid argon pump 1 increases to the rated value, the argon gas flows in the labyrinth sealing structure to form a dynamic sealing barrier, and the liquid argon begins to be delivered.

[0054] Step 2: Standby coasting. Liquid argon filling is completed. The control system controls liquid argon pump 1 to run at low speed, and high-purity argon gas is continuously supplied to maintain the dynamic sealing barrier. The filling device is in a pressure-holding standby state.

[0055] Step 3: Rapid Response Start-up. When the next filling command is transmitted to the control system, the control system controls the liquid argon pump 1 to directly increase its speed to the rated speed, and the liquid argon filling operation can be carried out directly.

[0056] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A liquid argon filling device, comprising a liquid argon pump, wherein the pump shaft of the liquid argon pump is provided with a plurality of rotor tooth grooves, and the end cover of the liquid argon pump is provided with a plurality of stator tooth grooves, the plurality of stator tooth grooves cooperating with the surface of the pump shaft to form a labyrinth seal structure, characterized in that, Also includes: An air inlet ring groove is located on the end cap and is connected to a high-purity argon gas source. The return gas ring groove is located on the end cover and is externally connected to an argon gas recovery device; The control system controls the operating modes of the liquid argon pump; the operating modes of the liquid argon pump include: In the liquid argon filling mode, a high-purity argon source delivers argon gas into the labyrinth sealing structure through the inlet ring groove, while the argon gas recovery device recovers argon gas through the return ring groove. The argon gas flows within the labyrinth sealing structure to form a dynamic sealing barrier. In standby coasting mode, after filling is complete, the control system controls the liquid argon pump to run at low speed, and high-purity argon gas is continuously supplied to maintain the dynamic sealing barrier.

2. The liquid argon filling device according to claim 1, characterized in that, The inlet ring groove is arranged in the middle of several stator tooth grooves, and several air outlet holes are opened on both sides of its end facing the pump shaft. In a unit time, the air output of several air outlet holes is less than the air filling volume of high-purity argon gas source into the inlet ring groove.

3. The liquid argon filling device according to claim 2, characterized in that, There are two return air ring grooves, which are arranged on both sides of several stator tooth grooves. Several air inlet holes are opened at the ends of the return air ring grooves facing the pump shaft, and the diameter of the air inlet holes is smaller than the diameter of the air outlet holes.

4. The liquid argon filling device according to claim 1, characterized in that, The stator tooth groove includes a stator base fixed to the end cover and a plurality of stator tooth rings arranged sequentially on the stator base, wherein the portion between two adjacent stator tooth rings is the stator tooth groove. The stator gear ring is divided into several segments on the shaft, with adjacent segments in sliding contact. Each segment of the stator gear ring is slidably arranged on the stator base, and in the sliding direction, a first elastic element is provided between each segment of the stator gear ring and the stator base.

5. The liquid argon filling device according to claim 4, characterized in that, Each segment of the stator gear ring has a slot at one end and an insert at the other end. The slot and insert between two adjacent segments of the stator gear ring are connected by a convex-concave fit.

6. The liquid argon filling device according to claim 5, characterized in that, The stator gear ring has a trapezoidal cross-section, with the width of the side facing the pump shaft being smaller than the width of the side contacting the stator base.

7. The liquid argon filling device according to claim 5, characterized in that, A first electromagnet is installed on the stator base at a position corresponding to each segment of the stator gear ring, and a second electromagnet is installed on each segment of the stator gear ring. The distance between the stator gear ring and the rotor tooth slot is controlled based on the magnetic force between the first electromagnet and the second electromagnet.

8. The liquid argon filling device according to claim 5, characterized in that, The pump shaft is provided with rotor tooth slots, which include a rotor base fixed to the pump shaft and a plurality of rotor tooth rings arranged sequentially on the rotor base, with the plurality of stator tooth rings and the plurality of rotor tooth rings arranged alternately.

9. The liquid argon filling device according to claim 8, characterized in that, The rotor gear ring has a trapezoidal cross-section, and its orientation is opposite to that of the stator gear ring.

10. A liquid argon filling method, based on the liquid argon filling apparatus according to any one of claims 1-9, characterized in that, The liquid argon filling method includes the following steps: Liquid argon filling: The control system receives the filling command, controls the liquid argon pump to rotate, and simultaneously controls the high-purity argon gas source to input argon gas into the labyrinth sealing structure. When the liquid argon pump speed increases to the rated value, the argon gas flows in the labyrinth sealing structure to form a dynamic sealing barrier, and the liquid argon begins to be delivered. After the liquid argon filling is completed, the control system controls the liquid argon pump to run at a low speed, and high-purity argon gas is continuously supplied to maintain the dynamic sealing barrier. The filling device is in a pressure-holding standby state. With rapid response and startup, when the next filling command is transmitted to the control system, the control system controls the liquid argon pump to directly increase its speed to the rated speed, and the liquid argon filling operation can be carried out directly.

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