Sampling device for collecting tiny samples

Abstract

The invention relates to the technical field of flaw detection sampling equipment, and discloses a sampling device for collecting tiny samples, the sampling device comprises a stepping motor, a planetary reducer, a motor base, a sampling assembly and a fixing assembly, the stepping motor and the planetary reducer are both arranged on the motor base, the planetary reducer is connected to the output end of the stepping motor, and the sampling assembly is arranged on the motor base. The sampling assembly is connected to an output shaft of the planetary reducer, and the fixing assembly is connected to the lower portion of the motor base. By arranging the profiling guide rail and the tension spring, the electrode can be cut in situ in the pipeline according to the needed shape, the cutting effect is good, the sampling assembly is driven by the stepping motor, the cutting amplitude is small, and damage to equipment is reduced. A set of water circulation system matched with the sampling device is designed, so that the use of water resources and the replacement period of cooling water in the sampling process are effectively reduced, and the pollution influence of an open type cooling system on the working environment in the in-situ sampling operation is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of flaw detection sampling equipment, and in particular to a sampling device for collecting tiny samples. Background Art

[0002] According to the sampling principle, micro-damage sampling machines are mainly divided into two types: mechanical samplers and electric spark samplers. Most mechanical samplers are based on the "spherical shell sampler". The sampling principle is: the tool is fixed in the sampling area by a telescopic rod. Under the control of the sampling system, the tool is fed while rotating at high speed. When the bowl-shaped tool turns a certain angle, the sampling is completed; while the spark sampler generates high temperature to melt the surface metal through electrode discharge, and the motor drives the electrode to feed to complete the sampling.

[0003] Most conventional EDM equipment is suitable for mass production and is not suitable for in-situ sampling. In addition, traditional sampling devices are generally bulky and inflexible, and most of them are fixed in design. Existing small sampling devices have a large demand for cooling water but a low utilization rate. On the one hand, frequent replacement of cooling water greatly increases the working time of the device for sampling. On the other hand, the open cooling water circuit not only causes a waste of water resources, but also pollutes the processing and production environment, which is particularly evident during the in-situ sampling process. Summary of the invention

[0004] The technical problem to be solved by the present invention is that the existing electric spark sampling device is large in size, inflexible in operation and has a low utilization rate of cooling water.

[0005] In order to solve the above technical problems, the technical solution of the present invention is to provide a sampling device for collecting micro samples, including a stepper motor, a planetary reducer, a motor base, a sampling component, and a fixing component. The stepper motor and the planetary reducer are both arranged on the motor base, and the planetary reducer is connected to the output end of the stepper motor, the sampling component is connected to the output shaft of the planetary reducer, and the fixing component is connected under the motor base.

[0006] Optionally, the motor base is "L-shaped", the stepper motor and the planetary reducer are located on the horizontal part of the motor base, and the output shaft of the planetary reducer passes through the vertical part of the motor base, the outer top of the vertical part of the motor base is connected with a contoured guide rail by bolts, and the sampling assembly includes a guide roller, one end of the guide roller is in contact with the contoured guide rail, and can move along the contoured guide rail.

[0007] Optionally, the sampling assembly also includes a spindle-shaped limiting element, a sliding base, a rotating arm, a T-shaped plate and an electrode assembly, the spindle-shaped limiting element is sleeved on the output shaft of the planetary reducer, the sliding base is located on the outside of the spindle-shaped limiting element and is sleeved on the output shaft of the planetary reducer, two T-shaped plates are provided, which are fixed to both sides of the sliding base by a first screw and a second screw respectively, a third screw is provided on the end of the T-shaped plate away from the sliding base, the rotating arm is located between the two T-shaped plates, and fourth screws are provided on both sides of the rotating arm below the third screw, a tension spring is connected between the third screw and the fourth screw, a through hole is provided at the upper end of the rotating arm, the other end of the guide roller is sleeved in the through hole, and the electrode assembly is connected to the outside of the rotating arm.

[0008] Optionally, the electrode assembly includes an insulating block, a fixed plate, a lifting plate, a clamping plate and an electrode, the insulating block is connected to the outside of the rotating arm by bolts, the fixed plate is connected to the insulating block by bolts, the fixed plate is provided with a plurality of bolt holes at different heights, the lifting plate is connected to the bolt holes of the fixing plate by bolts, the clamping plate is fixed on the lifting plate, and the clamping plate is provided with a grid-shaped groove for clamping the electrode.

[0009] Optionally, two limit switches are symmetrically provided at the bottom outer side of the vertical portion of the motor base.

[0010] Optionally, a slide rail is provided between the sliding base and the rotating arm, both ends of the slide rail are connected to the sliding base, and a sliding block is sleeved on the slide rail.

[0011] Optionally, the fixing assembly includes a fixed base plate and a clamping slider, at least two positioning protrusions are provided in the middle of the upper surface of the fixed base plate, the motor base is provided on the positioning protrusions and is connected with the positioning protrusion bolts, a sliding groove is provided on the fixed base plate, the clamping slider is located below the fixed base plate, and the upper end of the clamping slider is located in the sliding groove, and the clamping slider can slide along the sliding groove.

[0012] Optionally, the fixing component also includes a vacuum suction cup assembly, which includes a suction cup arm, a tripod, a mounting plate and a rubber suction cup, wherein the suction cup arm is arranged in the middle of the mounting plate and passes through the mounting plate, the tripod is arranged on the upper surface of the mounting plate and is connected to the suction cup arm and the mounting plate, the rubber suction cup is arranged at the lower end of the suction cup arm, the suction cup arm is provided with an exhaust hole for extracting air, at least two vacuum suction cup assemblies are provided, hinge holes are provided on both sides of the mounting plate, and the vacuum suction cup assemblies are respectively hinged on both sides of the fixing component.

[0013] Optionally, a cooling component is further included, which is located outside the sampling component. The cooling component includes a cooling pipe, a return water tank and a water tank. The return water tank includes a liquid collecting tank and a magnet block. The liquid collecting tank is located on one side of the return water tank, and a downward inclined liquid flow channel is provided inside the liquid collecting tank. A return water hole is provided at the end of the liquid flow channel. The return water hole is connected to the water tank through a cooling pipe. The magnet block is embedded on one side of the return water tank where the liquid collecting tank is provided.

[0014] Optionally, the water tank includes a filter element, a box body and a water pump, an end cover is provided at the upper end of the box body, a return water port, a water inlet and a water outlet are provided on the end cover, a filter element bracket is provided at a position corresponding to the water inlet and the water outlet inside the box body, the filter element is arranged in the filter element bracket, the water pump is located at the bottom of the box body, the water pump is connected to the water outlet through a cooling pipe, the return water port is connected to the return water hole on the return water tank through a cooling pipe, a drain faucet is provided at the bottom of the box body side, and a universal wheel is provided at the bottom of the box body.

[0015] In summary, the present invention has at least one of the following beneficial effects:

[0016] 1. The present invention provides a contoured guide rail and a tension spring, and through the cooperation of the two, the electrode can be cut in situ in the pipeline according to the required shape, with good cutting effect. The sampling assembly is driven by a stepper motor, and the cutting amplitude is small, which reduces damage to the equipment.

[0017] 2. The present invention can reduce the damage to the equipment during the sampling process by clamping and fixing the substrate and the vacuum suction cup assembly, while showing better curved surface fixing performance and even being able to adapt to more complex curved surfaces.

[0018] 3. The present invention designs a water circulation system that matches the sampling device, which effectively reduces the use of water resources and the replacement cycle of cooling water during the sampling process, and reduces the pollution impact of the open cooling system on the working environment during the in-situ sampling operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a side view of the structure of the sampling device for collecting micro samples of the present invention;

[0020] Figure 2 It is an axonometric diagram of a sampling device for collecting micro samples of the present invention;

[0021] Figure 3 It is a schematic diagram of the T-piece connection of the sampling device for collecting micro-samples of the present invention;

[0022] Figure 4 It is a schematic diagram of the T-shaped piece of the sampling device for collecting micro samples of the present invention;

[0023] Figure 5This is a schematic diagram of the fixed base plate structure of the sampling device for collecting micro samples of the present invention;

[0024] Figure 6 It is a schematic diagram of the overall structure of the fixing assembly of the sampling device for collecting micro-samples of the present invention;

[0025] Figure 7 It is a schematic diagram of the structure of the vacuum suction cup assembly of the sampling device for collecting micro samples of the present invention;

[0026] Figure 8 It is a schematic diagram of the structure of the water return tank of the sampling device for collecting micro samples of the present invention;

[0027] Fig. 9 It is a schematic diagram of the installation of the water return tank of the sampling device for collecting micro samples of the present invention;

[0028] Fig.10 This is a schematic diagram of the water tank structure of the sampling device for collecting micro samples of the present invention;

[0029] In the figure: 1. stepper motor; 2. planetary reducer; 3. motor base; 4. contoured guide rail; 5. guide roller; 6. spindle-shaped limit element; 7. limit switch; 8. sliding base; 9. slide rail; 10. slider; 11. rotating arm; 12. T-shaped piece; 13. insulating block; 14. fixed plate; 15. lifting plate; 16. clamping plate; 17. electrode; 18. first screw; 19. second screw; 20. third screw; 21. fourth screw; 22. fixed base plate; 23. clamping slider; 24. suction cup arm; 25. tripod; 26. mounting plate; 27. rubber suction cup; 28. end cover; 29. ​​filter element; 30. drain faucet; 31. box; 32. filter element bracket; 33. water pump; 34. universal wheel; 35. liquid collecting tank; 36. magnet block; 37. return tank. DETAILED DESCRIPTION

[0030] The following combination Figure 1-10 The present invention is described in further detail.

[0031] The present invention discloses a sampling device for collecting micro samples, referring to Figure 1 and Figure 2 , including a stepper motor 1, a planetary reducer 2, a motor base 3, a sampling component, and a fixing component. The stepper motor 1 and the planetary reducer 2 are both arranged on the motor base 3, and the planetary reducer 2 is connected to the output end of the stepper motor 1, which can reduce the output step length of the stepper motor. The sampling component is connected to the output shaft of the planetary reducer 2, and the fixing component is connected below the motor base 3.

[0032] In a further embodiment, the motor base 3 is "L-shaped", the stepper motor 1 and the planetary reducer 2 are located on the horizontal part of the motor base 3, and the output shaft of the planetary reducer 2 passes through the vertical part of the motor base 3. The outer top of the vertical part of the motor base 3 is connected with a contoured guide rail 4 by bolts, and the sampling component includes a guide roller 5, one end of the guide roller 5 is in contact with the contoured guide rail 4, and can move along the contoured guide rail 4. During the rotation of the output shaft of the planetary reducer 2, the guide roller 5 is always in contact with the contoured guide rail 4 and moves according to the shape of the contoured guide rail 4.

[0033] In a further embodiment, referring to Figure 3 and Figure 4 The sampling assembly also includes a spindle-shaped limiting element 6, a sliding base 8, a rotating arm 11, a T-shaped piece 12 and an electrode assembly. The spindle-shaped limiting element 6 is sleeved on the output shaft of the planetary reducer 2. The sliding base 8 is located outside the spindle-shaped limiting element 6 and sleeved on the output shaft of the planetary reducer 2. Two T-shaped pieces 12 are provided, which are fixed on both sides of the sliding base 8 by a first screw 18 and a second screw 19 respectively. A third screw 20 is provided on one end of the T-shaped piece 12 away from the sliding base 8. The rotating arm 11 is located between the two T-shaped pieces 12, and a fourth screw 21 is provided on both sides of the rotating arm 11 below the third screw 20. A tension spring is connected between the third screw 20 and the fourth screw 21. A through hole is provided at the upper end of the rotating arm 11, and the other end of the guide roller 5 is sleeved in the through hole. The electrode assembly is connected to the outside of the rotating arm 11, and two limit switches 7 are symmetrically provided at the bottom of the outer side of the vertical part of the motor base 3.

[0034] Specifically, the spindle-shaped limit element 6 is mounted on the output shaft of the planetary reducer 2 and rotates with the stepper motor 1. When the output shaft rotates through a certain angle, the limit element 6 presses the limit switch 7 to turn it on, and the device stops rotating. The limit switch 7 is installed at the lower part of the motor base 3 and is symmetrical about the main axis of the stepper motor 1. During the operation of the device, the tension spring and the contoured guide rail 4 generate a pair of forces in opposite directions on the intermediate mechanism, so that the mechanism remains balanced, and the guide roller 5 and the contoured guide rail 4 are always tightly fitted.

[0035] In a further embodiment, the electrode assembly includes an insulating block 13, a fixed plate 14, a lifting plate 15, a clamping plate 16 and an electrode 17. The insulating block 13 is connected to the outside of the rotating arm 11 by bolts. The insulating block 13 is fixed to the rotating arm 11 by screws to prevent the high voltage acting on the electrode 17 from reversely breaking down the stepping motor 1. The fixed plate 14 is connected to the insulating block 13 by bolts. The fixed plate 14 is provided with a plurality of bolt holes of different heights. The lifting plate 15 is connected to the bolt holes of the fixed plate 14 by bolts. The clamping plate 16 is fixed on the lifting plate 15. A grid-shaped groove for clamping the electrode 17 is provided in the clamping plate 16, so that the electrode 17 at different positions can be clamped. A slide rail 9 is provided between the sliding base 8 and the rotating arm 11. Both ends of the slide rail 9 are connected to the sliding base 8. A slider 10 is sleeved on the slide rail 9.

[0036] In a further embodiment, referring to Figure 5 The fixing assembly includes a fixing base plate 22 and a clamping slider 23. At least two positioning convex plates are provided in the middle of the upper surface of the fixing base plate 22. The motor base 3 is arranged on the positioning convex plates and is connected with the positioning convex plate bolts. A slide groove is provided on the fixing base plate 22. The clamping slider 23 is located below the fixing base plate 22, and the upper end of the clamping slider 23 is located in the slide groove. The clamping slider 23 can slide along the slide groove. Bolts and nuts are provided on one end of the clamping slider 23 located in the slide groove. When the clamping slider 23 moves to a suitable position, the nut can be tightened to fix the clamping slider 23.

[0037] In a further embodiment, referring to Figure 7 The fixing assembly also includes a vacuum suction cup assembly, which includes a suction cup arm 24, a tripod 25, a mounting plate 26 and a rubber suction cup 27. The suction cup arm 24 is arranged in the middle of the mounting plate 26 and passes through the mounting plate 26. The tripod 25 is arranged on the upper surface of the mounting plate 26 and connected to the suction cup arm 24 and the mounting plate 26. The rubber suction cup 27 is arranged at the lower end of the suction cup arm 24. The suction cup arm 24 is provided with an exhaust hole for exhausting air. There are at least two vacuum suction cup assemblies. Both sides of the mounting plate 26 are provided with hinge holes. The vacuum suction cup assemblies are respectively hinged on both sides of the fixing assembly;

[0038] Specifically, refer to Figure 6 The number of vacuum suction cup assemblies can be increased or decreased as needed. When additional vacuum suction cup assemblies are needed, the additional vacuum suction cup assemblies can be hinged to the hinge holes on the mounting plate 26 through hinges.

[0039] In a further embodiment, referring to Figure 8 and Fig.10, and also includes a cooling component, which is located outside the sampling component. The cooling component includes a cooling pipe, a return water tank 37 and a water tank. The return water tank 37 includes a collecting tank 35 and a magnet block 36. The collecting tank 35 is located on one side of the return water tank 37, and a downward inclined liquid flow channel is provided inside the collecting tank. A return water hole is provided at the end of the liquid flow channel. The return water hole is connected to the water tank through a cooling pipe. The magnet block is embedded on one side of the return water tank 37 where the collecting tank 35 is provided. The water tank includes a filter element 29, a box body 31 and a water pump 33. An end cover 28 is provided at the upper end of the box body 31, and a return water port, a water inlet and an outlet are provided on the end cover 28. Water inlet, a filter element bracket 32 ​​is provided at a position corresponding to the water inlet and the water outlet inside the box 31, a filter element 29 is provided in the filter element bracket 32, the bottom of the filter element 29 is densely covered with mesh holes, and a multi-layer filter material including sand, gauze, activated carbon, etc. is installed inside the filter element 29, a water pump 33 is located at the bottom of the box 31, the water pump 33 is connected to the water outlet through a cooling pipe, and the return water inlet is connected to the return water hole on the return water tank 37 through a cooling pipe, a drain tap 30 is provided at the bottom of the box 31, and the water in the box 31 can be emptied after sampling, and a universal wheel 34 is provided at the bottom of the box 31;

[0040] like Fig. 9 As shown, two return water tanks 37 are provided, which are placed on both sides of the sampling pipe respectively and adsorbed by magnet blocks 36. The cooling water flows out to both sides and is collected in the liquid collecting tank 35 of the return water tank 37, and then recovered into the water inlet tank 31.

[0041] Taking a chemical pipeline as an example, when installing the present invention, first inject a certain amount of cooling water into the water tank through the water inlet, then place the sampling device horizontally on the top of the pipeline, adjust the positions of the two clamping sliders 23 so that they fit tightly with the pipeline, lock the fixing bolts between the clamping slider 23 and the fixed base plate 22, and then adjust the position of the vacuum suction cup assembly so that it fits the pipeline surface, keep a certain distance between the electrode 17 and the pipeline, use a vacuum pump to evacuate the vacuum suction cup assembly to make the device completely fixed, then connect the circuit and the cooling loop, connect the positive electrode of the spark power supply to the sampling electrode 17, and the negative electrode to the pipeline, connect a universal faucet to the water outlet of the water tank, and ensure that the water outlet direction of the universal faucet is facing the sampling electrode 17, the water flow is stable and continuous, and then connect the controller and power supply required for spark sampling as required;

[0042] The spark sampling of the present invention uses PWM technology, and uses PWM to control pulsed electric spark machining to collect samples from the equipment surface, which can reduce the damage caused by surface sampling to the equipment and reduce the thermal impact on the sample during the sampling process. The PWM technology can accurately control the width of the pulse, thereby realizing accurate regulation of the discharge energy, which helps to improve the processing accuracy and surface quality. By adjusting the duty cycle of the pulse, PWM control can optimize the energy utilization efficiency, reduce the consumption of invalid energy, and improve the overall processing efficiency. Since PWM control can accurately control the discharge process, it can also effectively reduce the wear of the electrode and extend the service life of the electrode.

[0043] When in use, start the spark power supply, control the motor to rotate in small steps, make the electrode 17 close to the pipe surface until a stable spark appears, then enter the program automatic control stage, the sampling device starts to feed steadily until the sample of the required geometric shape is completely removed, during the sampling process, the water pump 33 draws water from the water tank through the pipe from the water outlet, flows through the sampled pipe surface, enters the return water tank 37 for collection, and then flows through the pipe through the return water port into the filter element 29, the filtered cooling water flows out from the mesh at the bottom of the filter element 29 and returns to the bottom of the water tank, after the sampling is completed, open the drain tap 30 to empty the water tank.

[0044] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A sampling device for collecting micro samples, characterized in that: The invention comprises a stepping motor (1), a planetary reducer (2), a motor base (3), a sampling component, and a fixing component. The stepping motor (1) and the planetary reducer (2) are both arranged on the motor base (3), and the planetary reducer (2) is connected to the output end of the stepping motor (1), the sampling component is connected to the output shaft of the planetary reducer (2), and the fixing component is connected below the motor base (3).

2. The sampling device for collecting micro samples according to claim 1, characterized in that: The motor base (3) is "L-shaped", the stepper motor (1) and the planetary reducer (2) are located on the horizontal part of the motor base (3), and the output shaft of the planetary reducer (2) passes through the vertical part of the motor base (3), and the top of the outer side of the vertical part of the motor base (3) is connected to a contoured guide rail (4) by bolts, and the sampling component includes a guide roller (5), one end of the guide roller (5) is in contact with the contoured guide rail (4), and can move along the contoured guide rail (4).

3. The sampling device for collecting micro samples according to claim 2, characterized in that: The sampling assembly further comprises a spindle-shaped limiting element (6), a sliding base (8), a rotating arm (11), a T-shaped piece (12) and an electrode assembly, wherein the spindle-shaped limiting element (6) is sleeved on the output shaft of the planetary reducer (2), the sliding base (8) is located outside the spindle-shaped limiting element (6) and sleeved on the output shaft of the planetary reducer (2), and two T-shaped pieces (12) are respectively fixed to the sliding base (8) by a first screw (18) and a second screw (19). On both sides, a third screw (20) is provided on one end of the T-shaped piece (12) away from the sliding base (8), the rotating arm (11) is located between the two T-shaped pieces (12), and a fourth screw (21) is provided on both sides thereof below the third screw (20), a tension spring is connected between the third screw (20) and the fourth screw (21), a through hole is provided at the upper end of the rotating arm (11), the other end of the guide roller (5) is sleeved in the through hole, and the electrode assembly is connected to the outside of the rotating arm (11).

4. The sampling device for collecting micro samples according to claim 3, characterized in that: The electrode assembly comprises an insulating block (13), a fixing plate (14), a lifting plate (15), a clamping plate (16) and an electrode (17); the insulating block (13) is connected to the outside of the rotating arm (11) by bolts; the fixing plate (14) is connected to the insulating block (13) by bolts; the fixing plate (14) is provided with a plurality of bolt holes of different heights; the lifting plate (15) is connected to the bolt holes of the fixing plate (14) by bolts; the clamping plate (16) is fixed to the lifting plate (15); and a grid-shaped groove for clamping the electrode (17) is provided in the clamping plate (16).

5. The sampling device for collecting micro samples according to claim 3, characterized in that: Two limit switches (7) are symmetrically arranged at the bottom outside the vertical part of the motor base (3).

6. The sampling device for collecting micro samples according to claim 3, characterized in that: A slide rail (9) is provided between the slide base (8) and the rotating arm (11), both ends of the slide rail (9) are connected to the slide base (8), and a sliding block (10) is sleeved on the slide rail (9).

7. The sampling device for collecting micro samples according to claim 1, characterized in that: The fixing assembly comprises a fixing base plate (22) and a clamping slide block (23), at least two positioning convex plates are provided in the middle of the upper surface of the fixing base plate (22), the motor base (3) is arranged on the positioning convex plates and is bolted to the positioning convex plates, a slide groove is provided on the fixing base plate (22), the clamping slide block (23) is located below the fixing base plate (22), and the upper end of the clamping slide block (23) is located in the slide groove, and the clamping slide block (23) can slide along the slide groove.

8. The sampling device for collecting micro samples according to claim 7, characterized in that: The fixing assembly also includes a vacuum suction cup assembly, which includes a suction cup arm (24), a tripod (25), a mounting plate (26) and a rubber suction cup (27). The suction cup arm (24) is arranged in the middle of the mounting plate (26) and passes through the mounting plate (26). The tripod (25) is arranged on the upper surface of the mounting plate (26) and is connected to the suction cup arm (24) and the mounting plate (26). The rubber suction cup (27) is arranged at the lower end of the suction cup arm (24). The suction cup arm (24) is provided with an exhaust hole for exhausting air. At least two vacuum suction cup assemblies are provided. Hinge holes are provided on both sides of the mounting plate (26). The vacuum suction cup assemblies are respectively hinged to the two sides of the fixing assembly.

9. The sampling device for collecting micro samples according to claim 1, characterized in that: The invention also comprises a cooling component, which is located outside the sampling component. The cooling component comprises a cooling pipe, a return water tank (37) and a water tank. The return water tank (37) comprises a liquid collecting tank (35) and a magnet block (36). The liquid collecting tank (35) is located on one side of the return water tank (37). A downwardly inclined liquid flow channel is provided inside the liquid collecting tank. A return water hole is provided at the end of the liquid flow channel. The return water hole is connected to the water tank through the cooling pipe. The magnet block is embedded on one side of the return water tank (37) where the liquid collecting tank (35) is provided.

10. The sampling device for collecting micro samples according to claim 9, characterized in that: The water tank comprises a filter element (29), a box body (31) and a water pump (33); an end cover (28) is provided at the upper end of the box body (31); a water return port, a water inlet and a water outlet are provided on the end cover (28); a filter element bracket (32) is provided at a position corresponding to the water inlet and the water outlet inside the box body (31); the filter element (29) is arranged in the filter element bracket (32); the water pump (33) is located at the bottom of the box body (31); the water pump (33) is connected to the water outlet through a cooling pipe; the water return port is connected to the water return hole on the water return tank (37) through a cooling pipe; a drainage tap (30) is provided at the bottom of the side of the box body (31); and a universal wheel (34) is provided at the bottom of the box body (31).

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