Testing machine for testing sealing performance of sealing pair of control valve

Abstract

The invention discloses a testing machine for testing the sealing performance of a sealing pair of a control valve, which comprises a closed box body, a rotary driving mechanism, a rotary lifting assembly, a lower sample replacement block, a telescopic cylinder, an upper sample replacement block, a liquid pressure supply system, a gas pressure supply system, a leakage detection system and a data acquisition and control system, and is characterized in that the rotary driving mechanism is mounted in the closed box body; the rotary lifting assembly is located in the closed box and is in transmission connection with the rotary driving mechanism. The lower sample replacement block is mounted at the top of the rotary lifting assembly; the telescopic cylinder is installed in the closed box body, and a telescopic rod of the telescopic cylinder is fixedly connected with the rotary lifting assembly. The upper sample replacement block is mounted at the top of the closed box body and corresponds to the lower sample replacement block in position; the liquid pressure supply system is connected and communicated with the sealed cavity of the upper sample replacement block; and the gas pressure supply system is aligned with a sealing interface formed between the upper sample replacement block and the lower sample replacement block. The method can improve the applicability, quantify the sealing leakage rate of the valve, and comprehensively evaluate the sealing performance of the control valve.

Description

Technical Field

[0001] The invention relates to the technical field of sealing performance testing equipment, and more particularly to a sealing performance testing machine for a control valve sealing pair. Background Art

[0002] High-end control valves are used in a wide range of fields and under special conditions, including ultra-high pressure and ultra-high temperature pipelines, nuclear island and conventional island safety systems, aircraft engine power systems, space station environmental control and life support systems, submarine surfacing and equalization systems, etc., which puts extremely stringent requirements on the sealing reliability of control valves. High-end control valve sealing pairs are different from traditional mechanical seals. Their service environment is mostly extremely harsh conditions such as high temperature, high pressure difference, strong corrosion, and strong wear, which will cause serious cavitation, erosion, corrosion, thermal deformation, blockage, crushing, scratches and other problems. Especially at the moment of opening and closing the control valve, a high-speed jet will be generated at the opening and closing gap, which will severely damage the surface of the sealing pair. In addition, the control valve sealing pair is different from traditional static and dynamic seals, and it is necessary to always maintain a high level of sealing performance during the static closing and dynamic opening of the control valve.

[0003] The current mainstream sealing theory is based on the sealing pressure ratio model, which can take into account the influence of sealing surface material properties, roughness and sealing surface size, and requires that the sealing pressure ratio generated by the sealing force should be greater than the required sealing pressure ratio. In the design of control valve seals under normal working conditions, the sealing pressure ratio model can provide good theoretical guidance, but in the development of high-end control valve products, it is found that the sealing pressure ratio theory can no longer meet the design requirements of extreme working conditions. Some products can still pass the sealing performance test even if the sealing surface indentation does not reach the design width (matching degree <65%); at the same time, some products cannot achieve sealing even if the sealing surface meets the model requirements. Therefore, the existing sealing pressure ratio model has great limitations. Its model parameters simplify the influence of elastic modulus, sealing surface width and roughness changes, lack of quantitative characterization of microscopic sealing mechanism, and cannot explain the basic principle of sealing from the essence, especially for the influence of fluids with extraordinary physical parameters, complex multiphase fluids, extreme temperatures, ultra-high pressures, and extreme loads on the sealing performance of control valves. It is difficult to evaluate and meet the design requirements of control valve seals under extreme working conditions.

[0004] In order to change the current situation, some control valve sealing performance test machines have also appeared in the prior art, which are used to detect the sealing performance of the control valve in the closed state, but there are still some technical problems:

[0005] For example, a Chinese patent with publication number CN219391251U and patent name "A device for detecting leakage of low-pressure gas sealing test of valves" discloses a device for detecting leakage of low-pressure gas sealing test of valves, including a high-precision gas flowmeter, a bubble counter, a bubble dish, a test valve, a right-side pressure gauge, a flow control component, and a right-side air intake valve. The device accurately counts the bubbles in the bubble dish through the bubble counter, or controls the leaking gas in the pipeline of the flow control component to flow to the high-precision gas flowmeter, so as to obtain the gas flow rate, and then the obtained measurement results are manually or transmitted to an intelligent device for calculation to determine whether the test valve meets the low-pressure gas sealing standard. Although the bubble counting method or flow metering method can solve the problem of low precision and poor accuracy in measuring the number of leakage bubbles and leakage flow in the existing device, the detection device is mainly aimed at the detection of low-pressure gas sealing performance, and may not be applicable to high-pressure environments or other types of sealing tests or need to be adjusted accordingly; in addition, the device is designed to detect the gas leakage of the valve under low-pressure conditions, and does not explicitly mention the detection capability of liquid leakage.

[0006] For another example, a Chinese patent with publication number CN117168706A and patent name “A Valve Sealing Performance Test Equipment” discloses a valve sealing performance test equipment, including a base; a rectangular cylinder with an upper end opening is installed on the upper end face of the base, an air injection pipe is arranged on the left side of the rectangular cylinder, a cover plate is arranged on the upper end face of the rectangular cylinder, a driving mechanism for driving the cover plate to fit with the rectangular cylinder is arranged on the base, a limiting mechanism for pre-limiting the valve is arranged at the lower end of the cover plate, a rotating mechanism for driving the valve to open and close is arranged on the cover plate, and two pressure-applying mechanisms for adjusting the internal pressure of the valve are symmetrically arranged on the left and right sides of the cover plate, which can detect whether the valve is completely sealed, in order to solve the problem in the related art that it is difficult to observe the tiny valve through a foam agent or a differential pressure gauge. There are technical issues such as leakage and the fact that the valve air tightness test can not fully evaluate the performance of the valve only under the same external pressure. However, the design of the equipment focuses on identifying tiny leaks of valves through underwater detection, but this method may not be reasonable for special materials or applications that cannot come into contact with water. In addition, the equipment is designed for specific types of valves, and customized adjustments may be required for valves of different sizes or types, which will increase the overall testing cost. Finally, the main goal of the equipment is to detect the sealing performance of the valve, especially to determine whether there is a tiny leak by observing whether bubbles are generated. This is a qualitative rather than quantitative detection method, and does not provide specific means to quantify the leakage, such as leakage rate or leakage volume.

[0007] Therefore, providing a control valve sealing performance testing machine is a problem that technical personnel in this field urgently need to solve. Summary of the invention

[0009] In view of this, the present invention provides a control valve sealing pair sealing performance testing machine, which can improve applicability, quantify valve sealing leakage, and comprehensively evaluate the control valve sealing performance.

[0010] In order to achieve the above object, the present invention adopts the following technical solution:

[0011] A control valve sealing performance tester comprises a closed box, a rotary drive mechanism, a rotary lifting assembly, a lower sample replacement block, a telescopic cylinder, an upper sample replacement block, a liquid pressure supply system, a gas pressure supply system, a leakage detection system and a data acquisition and control system, wherein the rotary drive mechanism is installed inside the closed box; the rotary lifting assembly is located inside the closed box and is transmission-connected to the rotary drive mechanism; the lower sample replacement block is installed on the top of the rotary lifting assembly; the telescopic cylinder is installed inside the closed box and its telescopic rod is fixedly connected to the rotary lifting assembly; the upper sample replacement block is installed on the top of the closed box and corresponds to the position of the lower sample replacement block; the liquid pressure supply system is connected to the sealed cavity of the upper sample replacement block; the gas pressure supply system is aligned with the sealing interface formed between the upper sample replacement block and the lower sample replacement block; and the leakage detection system is electrically connected to the data acquisition and control system.

[0012] Furthermore, the lower sample replacement block is conical, and the bottom plane of the lower sample replacement block is inclined downward from the conical body toward the cone head and a leakage hole is opened at the cone head position; the leakage detection system includes a beaker, an electronic balance and a helium mass spectrometer, the beaker is placed inside the closed box and is located directly below the leakage hole; the helium mass spectrometer is connected to the closed box; the electronic balance and the helium mass spectrometer are electrically connected to the data acquisition and control system respectively.

[0013] Furthermore, the rotary lifting assembly includes a base, an axis core, a bearing sleeve, a bearing, a disc gear and a bearing end cover, the telescopic rod of the telescopic cylinder is fixedly connected to the base; the axis core is located at the top of the base and is rotatably connected thereto; the bearing sleeve is sleeved on the axis core; a lower positioning shoulder is provided on the inner side of the bearing sleeve; the bearing is mounted on the axis core and is located inside the bearing sleeve; the disc gear is mounted on the bearing, and an upper positioning shoulder is provided on the inner side of the disc gear, the disc gear and the bearing sleeve are connected by screws so that the bearing is clamped between the lower positioning shoulder and the upper positioning shoulder; the lower sample replacement block is fixedly connected to the disc gear by a plurality of positioning pins; and the bearing end cover is mounted on the open end of the bearing.

[0014] Furthermore, the rotary drive mechanism includes a servo motor, a first bevel gear, a main shaft, a second bevel gear, a coupling and a gear shaft, the servo motor is installed in the closed housing; the first bevel gear is installed on the output shaft of the servo motor; the main shaft is vertically installed in the closed housing through a bearing seat; the second bevel gear is installed on the main shaft, and the second bevel gear is meshed and connected with the first bevel gear; the main shaft is connected to the gear shaft through the coupling; the columnar gear on the gear shaft is meshed and connected with the disc gear.

[0015] Furthermore, the inner diameter of the sealed cavity is smaller than the inner diameter of the columnar body in the middle of the lower sample replacement block.

[0016] Furthermore, the gas pressure supply system includes a helium cylinder, a compressed air pipe, a spray gun and a vacuum pump, and the helium cylinder is connected to the spray gun through the compressed air pipe; the compressed air pipe extends into the closed box so that the spray gun is aligned with the sealing interface.

[0017] Furthermore, the liquid pressure supply system includes a hydraulic pump, a connecting pipe and a throttle valve. The hydraulic pump is connected to the sealed cavity through the connecting pipe; the throttle valve is installed on the connecting pipe.

[0018] Furthermore, the enclosed box includes a box body and a door, and the door is hinged to the box body and connected to the box body through a magnetic lock.

[0019] It can be seen from this that the present invention provides a control valve sealing pair sealing performance test machine. Compared with the prior art, the present invention produces the following beneficial effects:

[0020] 1) It has the dual ability to detect liquid and gas leakage at the same time, which can meet the detection needs of different leakage amounts on the sealing interface.

[0021] 2) The telescopic rod can adjust the pressure on the sealing interface to simulate the working state of the control valve under different external pressure conditions, and based on this, the sealing performance can be tested to more comprehensively evaluate the sealing performance of the control valve and improve the accuracy of the test results.

[0022] 3) The combination of the rotary drive mechanism and the rotary lifting assembly can truly simulate the working conditions of the butterfly valve or ball valve at the moment of opening and closing, providing an important basis for the processing and manufacturing of valve prototypes. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0024] Figure 1 The accompanying drawing is a three-dimensional structural schematic diagram of a control valve sealing pair sealing performance testing machine provided by the present invention;

[0025] Figure 2 The accompanying drawing is a front view of a control valve sealing pair sealing performance testing machine provided by the present invention;

[0026] Figure 3 The accompanying drawing is an exploded view of the rotary lifting assembly provided by the present invention;

[0027] Figure 4 The accompanying drawing is a schematic structural diagram of a lower sample replacement block provided by the present invention;

[0028] Figure 5 The accompanying drawing is a schematic structural diagram of an upper sample replacement block provided by the present invention;

[0029] Figure 6 The accompanying drawing is a cross-sectional view of the upper sample replacement block provided by the present invention. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] like Figure 1-6As shown, an embodiment of the present invention discloses a control valve sealing performance test machine, including a closed box 1, a rotary drive mechanism 2, a rotary lifting assembly 3, a lower sample replacement block 4, a telescopic cylinder 5, an upper sample replacement block 6, a liquid pressure supply system, a gas pressure supply system, a leakage detection system and a data acquisition and control system. A sealed cabin is formed inside the closed box 1; the rotary drive mechanism 2 is installed inside the closed box 1; the rotary lifting assembly 3 is located inside the closed box 1 and is transmission-connected to the rotary drive mechanism 2; the lower sample replacement block 4 is installed on the top of the rotary lifting assembly 3; the telescopic cylinder 5 is installed inside the closed box 1 and its telescopic rod is fixedly connected to the rotary lifting assembly 3 to provide a contact load, and a pressure sensor is provided at the front end of the telescopic cylinder 5 to real-time Monitor the test load; the upper sample replacement block 6 is installed on the top of the closed box 1 and corresponds to the position of the lower sample replacement block 4. In this embodiment, the upper sample replacement block 6 is connected to the top of the closed box 1 by bolts, and steel gaskets and rubber gaskets are used at the contact point between the bolts and the top of the closed box 1 to isolate the vibration interaction between the bolts and the metal plate of the closed box 1, so as to obtain more accurate test results; the liquid pressure supply system is connected and communicated with the sealing cavity 61 of the upper sample replacement block 6 to provide pressure fluid for the sealing cavity 61; the gas pressure supply system is aligned with the sealing interface formed between the upper sample replacement block 6 and the lower sample replacement block 4; the leakage detection system is electrically connected to the data acquisition and control system, and the output end of the data acquisition and control system is connected to the computer. The present invention has the dual ability of detecting liquid and gas leakage at the same time, can meet the detection requirements of different leakage amounts of the sealing interface, improve applicability, and quantify the valve seal leakage at the same time, and comprehensively evaluate the sealing performance of the control valve.

[0032] Specifically, the lower sample replacement block 4 is conical, and the bottom plane of the lower sample replacement block 4 is inclined downward from the conical body to the cone head and a leakage hole is opened at the cone head; the leakage detection system includes a beaker, an electronic balance and a helium mass spectrometer, the beaker is placed inside the closed box 1 and is located directly below the leakage hole, so that the leaking liquid can flow smoothly into the beaker for accurate measurement, which is convenient for collecting the liquid leaked from the sealing interface; the helium mass spectrometer is connected to the closed box 1; the electronic balance and the helium mass spectrometer are electrically connected to the data acquisition and control system respectively, and the electronic balance needs to be zeroed and calibrated before the test starts. After the fluid is passed into the sealed cavity 61 of the upper sample replacement block 6, the liquid leaks from the sealing interface to the external environment under the driving force of pressure, and the leaked liquid flows into the beaker through the leakage hole along the inclined surface, and the electronic balance is used to measure the mass of the beaker before and after the test, and the mass difference is the leakage amount of the sealing interface.

[0033] Specifically, the rotary lifting assembly 3 includes a base 31, a shaft core 32, a bearing sleeve 33, a bearing 34, a disc gear 35 and a bearing end cover 36. The telescopic rod of the telescopic cylinder 5 is fixedly connected to the base 31; the shaft core 32 is located at the top of the base 31 and is rotatably connected thereto; the bearing sleeve 33 is sleeved on the shaft core 32; a lower positioning shoulder is provided on the inner side of the bearing sleeve 33; the bearing 34 is mounted on the shaft core 32 and is located inside the bearing sleeve 33. In this embodiment, the bearing 34 adopts a deep groove ball bearing, and a mounting sleeve made of a soft metal material is padded on the end face of the inner ring of the deep groove ball bearing to be mounted on the shaft core 32; the disc gear 35 is mounted on the bearing 34, and an upper positioning shoulder is provided on the inner side of the disc gear 35. The disc gear 35 is connected to the bearing sleeve 33 by screws, so that the bearing 34 is clamped between the lower positioning shoulder and the upper positioning shoulder; the lower sample replacement block 4 is fixedly connected to the disc gear 35 by multiple positioning pins 37; and the bearing end cover 36 is mounted on the open end of the bearing 34.

[0034] Specifically, the rotary drive mechanism 2 includes a servo motor 21, a first bevel gear 22, a main shaft 23, a second bevel gear 24, a coupling 25 and a gear shaft 26. The servo motor 21 is installed in the closed box 1; the first bevel gear 22 is installed on the output shaft of the servo motor 21; the main shaft 23 is vertically installed in the closed box 1 through a bearing seat; the second bevel gear 24 is installed on the main shaft 23, and the second bevel gear 24 is meshed and connected with the first bevel gear 22; the main shaft 23 is connected to the gear shaft 26 through the coupling 25; the gear shaft 2 The columnar gear 27 on 6 is meshed and connected with the disc gear 35. When the servo motor 21 is started, the power output thereof drives the bevel gear set to rotate, and the bevel gear set drives the main shaft 23 to rotate. The main shaft 23 drives the gear shaft 26 to rotate under the connection action of the coupling 25, that is, the columnar gear 27 on the gear shaft 26 rotates, thereby driving the disc gear 35 to rotate. Since the disc gear 35 cooperates with the outer ring of the deep groove ball bearing, the friction force is extremely small during rotation. The rotation of the disc gear 35 further drives the lower sample replacement block 4 connected thereto to rotate.

[0035] Specifically, the height of the column gear 27 is greater than the height of the disc gear 35 , so that even if the disc gear 35 moves up and down under the action of the telescopic cylinder 5 , it is still ensured to be meshed with the column gear 27 .

[0036] In order to further optimize the technical solution of the present invention, the inner diameter of the sealed cavity 61 is smaller than the inner diameter of the columnar body in the middle of the lower sample replacement block 4, so as to facilitate centering.

[0037] Specifically, the gas pressure supply system includes a helium cylinder, a compressed air pipe, a spray gun and a vacuum pump. The helium cylinder is connected to the spray gun through a compressed air pipe. In this embodiment, the compressed air pipe and the helium cylinder are connected by a quick connector and tightened with a wrench to ensure sealing. The spray gun is provided with a pressure regulator, and the compressed air pipe and the pressure regulator are connected by a quick connector; the compressed air pipe extends into the sealed box 1 so that the spray gun is aligned with the sealing interface. When working, the vacuum pump extracts the air in the sealed box 1 until the required vacuum degree is reached, and the pressure of the sealed box 1 is stabilized for a period of time to ensure that there is no obvious pressure fluctuation. The main valve of the helium cylinder is opened to release the helium, and the pressure of the helium is adjusted through the pressure regulator to reach a pressure suitable for injection. After the helium passes through the pressure regulator, it is sprayed onto the sealing interface to be detected through the spray gun, and the reading of the helium mass spectrometer is observed, and the change of the helium concentration detected by the helium mass spectrometer over time is recorded.

[0038] Specifically, the liquid pressure supply system includes a hydraulic pump, a connecting pipe and a throttle valve. The hydraulic pump is connected to the sealed cavity 61 through the connecting pipe; the throttle valve is installed on the connecting pipe. Of course, in order to ensure the sealing performance, sealant is applied to the connection between the connecting pipe and the upper sample replacement block 6 to prevent leakage in the non-measurement area during the test, which affects the leakage rate measurement accuracy. When working, turn on the hydraulic pump to pump the pressure fluid into the sealed cavity 61, exhaust the air in the sealed cavity 61, and maintain the fluid pressure for several minutes. During the pressure maintenance period, due to leakage at the sealing interface, the pressure of the liquid in the sealed cavity 61 will drop. In order to maintain the test pressure, the fluid needs to be pressurized regularly.

[0039] Specifically, the enclosed box 1 includes a box body 11 and a hatch 12. The hatch 12 is hinged to the box body 11 and connected by a magnetic lock to facilitate opening while ensuring good sealing performance. The hatch 12 is made of transparent high-strength material, which not only ensures the strength but also facilitates observation of the internal situation; of course, in order to ensure the rigidity and stability of the telescopic cylinder 5, a perforated cross plate is provided in the middle of the box body 11, and the telescopic rod of the telescopic cylinder 5 passes through the perforated cross plate.

[0040] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0041] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control valve sealing pair sealing performance tester, characterized in that: It includes a closed box, a rotary drive mechanism, a rotary lifting assembly, a lower sample replacement block, a telescopic cylinder, an upper sample replacement block, a liquid pressure supply system, a gas pressure supply system, a leakage detection system and a data acquisition and control system, wherein the rotary drive mechanism is installed inside the closed box; the rotary lifting assembly is located inside the closed box and is transmission-connected to the rotary drive mechanism; the lower sample replacement block is installed on the top of the rotary lifting assembly; the telescopic cylinder is installed inside the closed box and its telescopic rod is fixedly connected to the rotary lifting assembly; the upper sample replacement block is installed on the top of the closed box and corresponds to the position of the lower sample replacement block; the liquid pressure supply system is connected to the sealed cavity of the upper sample replacement block; the gas pressure supply system is aligned with the sealing interface formed between the upper sample replacement block and the lower sample replacement block; and the leakage detection system is electrically connected to the data acquisition and control system.

2. A control valve sealing pair sealing performance tester according to claim 1, characterized in that: The lower sample replacement block is conical in shape, and the bottom plane of the lower sample replacement block is inclined downward from the conical body toward the cone head and a leakage hole is opened at the cone head; the leakage detection system includes a beaker, an electronic balance and a helium mass spectrometer, the beaker is placed inside the closed box and is located directly below the leakage hole; the helium mass spectrometer is connected to the closed box; the electronic balance and the helium mass spectrometer are electrically connected to the data acquisition and control system respectively.

3. A control valve sealing pair sealing performance tester according to claim 1, characterized in that: The rotary lifting assembly includes a base, an axis core, a bearing sleeve, a bearing, a disc gear and a bearing end cover, the telescopic rod of the telescopic cylinder is fixedly connected to the base; the axis core is located at the top of the base and is rotatably connected thereto; the bearing sleeve is sleeved on the axis core; a lower positioning shoulder is provided on the inner side of the bearing sleeve; the bearing is mounted on the axis core and located inside the bearing sleeve; the disc gear is mounted on the bearing, and an upper positioning shoulder is provided on the inner side of the disc gear, the disc gear and the bearing sleeve are connected by screws so that the bearing is clamped between the lower positioning shoulder and the upper positioning shoulder; the lower sample replacement block is fixedly connected to the disc gear by a plurality of positioning pins; the bearing end cover is mounted on the open end of the bearing.

4. A control valve sealing pair sealing performance tester according to claim 3, characterized in that: The rotary drive mechanism includes a servo motor, a first bevel gear, a main shaft, a second bevel gear, a coupling and a gear shaft. The servo motor is installed in the closed housing; the first bevel gear is installed on the output shaft of the servo motor; the main shaft is vertically installed in the closed housing through a bearing seat; the second bevel gear is installed on the main shaft, and the second bevel gear is meshed and connected with the first bevel gear; the main shaft is connected to the gear shaft through the coupling; the columnar gear on the gear shaft is meshed and connected with the disc gear.

5. A control valve sealing pair sealing performance tester according to claim 1, characterized in that: The inner diameter of the sealed cavity is smaller than the inner diameter of the columnar body in the middle of the lower sample replacement block.

6. A control valve sealing pair sealing performance tester according to claim 1, characterized in that: The gas pressure supply system includes a helium cylinder, a compressed air pipe, a spray gun and a vacuum pump. The helium cylinder is connected to the spray gun through the compressed air pipe; the compressed air pipe extends into the closed box so that the spray gun is aligned with the sealing interface.

7. A control valve sealing pair sealing performance tester according to claim 1, characterized in that: The liquid pressure supply system comprises a hydraulic pump, a connecting pipe and a throttle valve. The hydraulic pump is connected to the sealed cavity through the connecting pipe. The throttle valve is installed on the connecting pipe.

8. The control valve sealing pair sealing performance testing machine according to claim 1 is characterized in that: The enclosed box includes a box body and a door, and the door is hinged to the box body and connected via a magnetic lock.

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