Petroleum hydrocarbon contaminated soil remediation device

Abstract

The utility model belongs to the technical field of soil remediation, and particularly relates to a petroleum hydrocarbon contaminated soil remediation device which comprises a treatment cylinder, a rotating cylinder, a liquid spraying assembly and a stirring assembly, the top of the treatment cylinder is open, the rotating cylinder is horizontally and rotationally arranged between the inner walls of the treatment cylinder, and a plurality of filtering holes are formed in the circumferential side wall of the rotating cylinder; a feeding port is formed in the side wall of the rotary drum, a movable door is hinged to the feeding port, the movable door and the rotary drum are locked through a locking piece, a first motor for driving the rotary drum to rotate is arranged on the side wall of the treatment drum, the liquid spraying assembly is arranged at the top of the treatment drum, and the stirring assembly is arranged in the treatment drum and located below the rotary drum. And the discharge pipe is arranged on the side wall of the treatment cylinder and is communicated with the interior of the treatment cylinder. The soil screening device solves the problem that in the prior art, when polluted soil is screened, the screening device is static, so that part of soil blocks the screening device, and the screening efficiency is low.

Description

Technical Field

[0001] The utility model belongs to the technical field of soil restoration, in particular to a petroleum hydrocarbon polluted soil restoration device. Background Art

[0002] Petroleum hydrocarbon soil remediation refers to a series of measures and methods for soil contaminated by petroleum hydrocarbon compounds (such as petroleum, petroleum products, fuel oil, etc.) to restore the natural ecological functions of the soil and reduce environmental pollution. Generally, physical, chemical or biological methods are used to remove petroleum hydrocarbon pollutants in the soil. In the process of remediating contaminated soil, the surface area of ​​the soil can be increased by crushing the soil, thereby increasing its contact area with the remediation agent and promoting chemical reactions.

[0003] The Chinese utility model patent published on September 28, 2021, with publication number CN214290005U, discloses "a petroleum hydrocarbon contaminated soil remediation and purification device", which puts the contaminated soil into a screening box, and the filter screen in the screening box screens the soil, and drives the motor to control the blade to crush the larger volume of soil, so that the sufficiently fine soil enters the shell. This part of the soil is mixed with the oxidant under the action of the stirring rod to achieve the purpose of purification. During the implementation of this utility model patent, although the blade in the screening box crushes the larger volume of soil, because the filter screen is stationary, some of the soil will accumulate and agglomerate on the top of the filter screen, blocking the mesh of the filter screen. Utility Model Content

[0004] Aiming at the problem in the prior art that when screening contaminated soil, the screening device is stationary so that part of the soil blocks the screening device and leads to low screening efficiency, the utility model aims to provide a petroleum hydrocarbon contaminated soil remediation device.

[0005] The purpose of this utility model is achieved through the following technical solutions:

[0006] The utility model comprises a treatment cylinder, a rotary cylinder, a liquid spraying assembly and a stirring assembly, wherein the top of the treatment cylinder is an open structure, the rotary cylinder is rotatably installed in the treatment cylinder, a feed port is provided on the rotary cylinder, a movable door that can be opened and closed is installed at the feed port, and contaminated soil is put into the rotary cylinder through the movable door, a plurality of filter holes are provided on the cylinder wall and the movable door of the rotary cylinder, and a rotary cylinder power source for driving the rotary cylinder to rotate is fixed on the treatment cylinder; the liquid spraying assembly is arranged on the top of the treatment cylinder and located above the rotary cylinder, the stirring assembly is located in the treatment cylinder and located below the rotary cylinder, the repair liquid sprayed by the liquid spraying assembly enters the rotary cylinder through the filter holes and is mixed with the contaminated soil in the rotary cylinder, the mixed contaminated soil is crushed in the rotary cylinder, filtered out by each of the filter holes, and then stirred by the stirring assembly; a discharge pipe is installed on the treatment cylinder, one end of the discharge pipe is connected with the inside of the treatment cylinder, and the other end of the discharge pipe is located outside the treatment cylinder, and the stirred soil is discharged through the discharge pipe.

[0007] Wherein: a plurality of spikes are evenly arranged on the inner wall of the rotating drum along the circumferential direction.

[0008] The rotating drum is horizontally arranged in the processing drum, that is, the axial center line of the rotating drum is parallel to the horizontal plane.

[0009] The liquid spray assembly includes a mounting plate, a water delivery plate and a nozzle. The water delivery plate is fixed to the top of the treatment cylinder through the mounting plate. The water delivery plate is an internal hollow structure. A plurality of nozzles are provided on the lower surface of the water delivery plate facing the rotating cylinder. Each of the nozzles is connected to the interior of the water delivery plate.

[0010] The stirring assembly includes a stirring power source, a stirring shaft and stirring blades. The stirring shaft is rotatably installed in the processing cylinder. The stirring power source is fixed at the bottom of the processing cylinder. The output end of the stirring power source is connected to the stirring shaft to drive the stirring shaft to rotate. A plurality of stirring blades are installed on the stirring shaft.

[0011] Each stirring blade is arranged obliquely with respect to the axial center line of the stirring shaft.

[0012] The stirring blades are arranged in multiple groups along the axial direction of the stirring shaft, and each group of two stirring blades are symmetrically arranged about the axial center line of the stirring shaft. The inclination directions of the two stirring blades in each group are opposite, and the projections of two adjacent groups of stirring blades on the horizontal plane are "X" shaped.

[0013] A scraper is vertically provided at one end of the stirring blade away from the stirring shaft, and one end of the scraper away from the stirring blade abuts against the inner wall of the processing cylinder.

[0014] One end of the stirring shaft is connected to the output end of the stirring power source, and the other end of the stirring shaft is provided with a spherical boss.

[0015] One end of the movable door is hinged to the rotating drum, and the other end of the movable door is a free end, and the free end is locked with the rotating drum through a locking member; the locking member includes a protrusion and a bolt, the protrusion is fixed to the free end of the movable door, and the bolt is threadedly connected to the protrusion; a groove is provided on the outer wall of the rotating drum at a position corresponding to the protrusion when the movable door is closed, and a screw hole is provided in the groove at a position corresponding to the bolt, the protrusion is embedded in the groove when the movable door is closed, and the bolt is threadedly connected to the screw hole.

[0016] The advantages and positive effects of the utility model are:

[0017] 1. The utility model releases the locking piece to open the movable door, puts the contaminated soil into the drum, drives the drum to rotate by the first motor, and sprays the repair liquid to the drum. The soil in the drum is infiltrated by the repair liquid and rotates with the drum, and continuously falls from a high place and changes its position, so that the soil is not easy to be blocked on the filter holes, and the crushing and splitting of the soil is accelerated, so that smaller soil is filtered out from the filter holes to the bottom of the processing drum, and after being evenly mixed with the repair liquid again by the stirring component in the processing drum, it is discharged through the discharge pipe, thereby realizing efficient screening and repair treatment of contaminated soil and improving the treatment capacity of contaminated soil.

[0018] 2. The utility model provides spikes on the inner wall of the drum, which facilitates rapid crushing of large pieces of soil in the drum and improves the filtration efficiency of the filter holes on the drum.

[0019] 3. The stirring blades of the utility model are tilted, and can exert an upward turning force on the soil during rotation, so that the soil at various heights in the treatment barrel can be fully mixed and mixed more evenly with the repair liquid.

[0020] 4. A scraper is provided at one end of the stirring blade away from the stirring shaft, which can scrape the inner wall of the treatment cylinder to avoid soil accumulation on the inner wall of the treatment cylinder, effectively prevent the residual soil from agglomerating on the inner wall of the treatment cylinder for a long time, so that all the soil can be mixed with the repair liquid, and the subsequent cleaning of the treatment cylinder is also easier.

[0021] 5. A spherical boss is provided at the upper end of the stirring shaft of the utility model to prevent the soil in the drum from falling onto the end of the stirring shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a three-dimensional structural schematic diagram of the utility model;

[0023] Figure 2 This is a cross-sectional view of the internal structure of the utility model;

[0024] Figure 3 This is a schematic diagram of the three-dimensional structure of the utility model after removing the processing cylinder and the liquid spraying component;

[0025] Figure 4 It is a structural schematic diagram of the locking member of the utility model;

[0026] Among them: 1 is a treatment cylinder, 2 is a rotating cylinder, 3 is a filter hole, 4 is a movable door, 5 is a first motor, 6 is a discharge pipe, 7 is a spike part, 8 is a mounting plate, 9 is a water delivery plate, 10 is a nozzle, 11 is a stirring shaft, 12 is a second motor, 13 is a stirring blade, 14 is a scraper, 15 is a spherical boss, 16 is a bump, 17 is a bolt, and 18 is a support column. DETAILED DESCRIPTION

[0027] The utility model is further described in detail below in conjunction with the accompanying drawings.

[0028] like Figures 1 to 4 As shown, the utility model comprises a treatment drum 1, a rotating drum 2, a liquid spraying assembly and a stirring assembly, wherein the top of the treatment drum 1 is an open structure, the rotating drum 2 is rotatably installed in the treatment drum 1, a feed port is provided on the rotating drum 2, a movable door 4 which can be opened and closed is installed at the feed port, and the contaminated soil is put into the rotating drum 2 through the movable door 4, a plurality of filter holes 3 are provided on the drum wall of the rotating drum 2 and the movable door 4, each filter hole 3 is connected to the inside of the rotating drum 2, and a rotating drum power source for driving the rotating drum 2 to rotate is fixed on the treatment drum 1; the liquid spraying assembly is arranged at the treatment drum 1 The top of the treatment drum 1 is located above the rotating drum 2, the stirring component is located in the treatment drum 1 and below the rotating drum 2, the repair liquid sprayed by the spray component enters the rotating drum 2 through the filter holes 3 and is mixed with the contaminated soil in the rotating drum 2, the mixed contaminated soil is crushed in the rotating drum 2, filtered out by the filter holes 3, and then stirred by the stirring component; a discharge pipe 6 is installed on the treatment drum 1, one end of the discharge pipe 6 is connected to the inside of the treatment drum 1, and the other end of the discharge pipe 6 is located outside the treatment drum 1, and the stirred soil is discharged through the discharge pipe 6.

[0029] like Figure 1 As shown, the treatment tube 1 of this embodiment is a hollow cylindrical tube with an open top and supported on the ground by three support columns 18 at the bottom. The discharge pipe 6 is arranged near the bottom of the treatment tube 1. Preferably, a valve for controlling the opening and closing of the discharge pipe 6 is arranged in the discharge pipe 6 of this embodiment.

[0030] like Figure 1 and Figure 2As shown, the drum 2 of this embodiment is horizontally arranged in the treatment drum 1, that is, the axial center line of the drum 2 is parallel to the horizontal plane; the drum 2 is rotatably arranged in the treatment drum 1 through two rotating shafts. The power source of the drum of this embodiment is the first motor 5, which is fixed on the outer wall of the treatment drum 1, and the output shaft of the first motor 5 is connected to one of the rotating shafts, and then the drum 2 is driven to rotate through the first motor 5. In this embodiment, multiple groups of filter holes 3 are evenly opened on the drum wall and the movable door 4 of the drum 2 along the circumferential direction, and each group of filter holes 3 is multiple and arranged along the axial direction of the drum 2.

[0031] like Figure 2 As shown, in this embodiment, a plurality of spikes 7 are provided on the inner wall of the drum 2 at equal intervals along the circumferential direction, and the end faces of the spikes 7 are triangular, with the tips facing the inside of the drum 2. Some large pieces of soil rotate with the drum 2, and when they rotate to the highest point of the inner wall of the drum 2, they fall onto the spikes 7 on the inner wall, and the large pieces of soil are quickly broken by the piercing of the soil by the spikes 7, thereby improving the filtration efficiency of each filter hole 3 on the drum 2.

[0032] like Figure 1 and Figure 4 As shown, one end of the movable door 4 of this embodiment is hinged to the rotating drum 2, and the other end of the movable door 4 is a free end, which is locked with the rotating drum 2 through a locking member. The locking member of this embodiment includes a protrusion 16 and a bolt 17, the protrusion 16 is fixed to the free end of the movable door 4, and the bolt 17 is threadedly connected to the protrusion 16; a groove is provided on the outer wall of the rotating drum 2 at a position corresponding to the protrusion 16 when the movable door 4 is closed, and a screw hole is provided in the groove at a position corresponding to the bolt 17, the protrusion 16 is embedded in the groove when the movable door 4 is closed, and the bolt 17 is threadedly connected to the screw hole. When the movable door 4 is locked on the rotating drum 2, the free end of the movable door 4 is rotated so that the protrusion 16 on the free end of the movable door 4 is just embedded in the groove of the rotating drum 2, and then the bolt 17 is tightened so that one end of the bolt 17 is threadedly connected to the screw hole of the groove, thereby completing the locking of the movable door 4.

[0033] like Figure 1 and Figure 2As shown, the liquid spraying assembly of this embodiment includes a mounting plate 8, a water delivery plate 9 and a nozzle 10. The mounting plates 8 are two pieces, and the two mounting plates 8 are symmetrically arranged on the top of the treatment barrel 1. The water delivery plate 9 is arranged between the two mounting plates 8. The water delivery plate 9 of this embodiment is an internal hollow structure, and a plurality of nozzles 10 are arranged on the lower surface of the water delivery plate 9 facing the rotating drum 2, and each nozzle 10 is connected to the inside of the water delivery plate 9. The water delivery plate 9 is supplied with liquid through an external water delivery pump and a hose, and the nozzle 10 sprays the repair liquid to the treatment barrel 1. Part of the repair liquid enters the rotating drum 2 through the filter hole 3 and mixes with the soil, and part of the repair liquid falls to the bottom of the treatment barrel 1, waiting for the stirring component to stir it with the soil. The repair liquid can be a biological repair liquid, an oxidant or a reducing agent. The biological repair liquid is a commercially available product. You can purchase the "Microbial Composite Bacterial Agent" model ZK-01 from the Ecological and Environmental Research Center of the Chinese Academy of Sciences. According to the degree of pollution and soil conditions, add 1 to 2 kilograms per cubic meter of soil; or you can purchase the "Petroleum Contaminated Soil Remediation Bacterial Agent" model KH-PRB from Beijing Kehai Huake Technology Co., Ltd., and add 2 to 5 kilograms per cubic meter of contaminated soil; or you can purchase the "Environmentally Friendly Petroleum Degrading Bacterial Agent" model SH-B100 from Shanghai Biotechnology Co., Ltd., and add 1 to 3 kilograms per cubic meter of contaminated soil; or you can purchase the "Soil Petroleum Hydrocarbon Degrading Bacteria" model HX-T100 from Suzhou Huaxiang Biotechnology Co., Ltd., and add 2 to 4 kilograms per cubic meter of contaminated soil. The oxidant can be hydrogen peroxide or persulfate, the mass concentration of hydrogen peroxide is 10-35%, the dosage is 10-100 kg / m3 soil, the mass concentration of persulfate is 10-20%, the dosage is 5-20 kg / m3 soil. The reducing agent can be ferrous sulfate or sodium borohydride, the mass concentration of ferrous sulfate is 5-10%, the dosage is 2-10 kg / m3 soil, the mass concentration of sodium borohydride is 1-5%, the dosage is 0.1-0.5 kg / m3 soil. The biological repair liquid of this embodiment adopts the "petroleum contaminated soil remediation bacterial agent" of Beijing Kehai Huake Technology Co., Ltd., and the dosage is 4 kg per cubic meter of contaminated soil.

[0034] like Figure 2 and Figure 3As shown, the stirring assembly of this embodiment includes a stirring power source, a stirring shaft 11 and a stirring blade 13. The stirring shaft 11 is rotatably installed in the treatment barrel 1. The stirring power source is fixed at the bottom of the treatment barrel 1. The output end of the stirring power source is connected to the stirring shaft 11 to drive the stirring shaft 11 to rotate. A plurality of stirring blades 13 are installed on the stirring shaft 11. The stirring power source of this embodiment is a second motor 12, which is fixed at the bottom of the treatment barrel 1; the stirring shaft 11 is rotatably installed on the treatment barrel 1, and the axial center line of the stirring shaft 11 is colinear with the axial center line of the treatment barrel 1 and intersects vertically with the axial center line of the rotating drum 2; the lower end of the stirring shaft 11 is connected to the output shaft of the second motor 12 and is driven to rotate by the second motor 12. When working, the second motor 12 is started, the second motor 12 drives the stirring shaft 11 to rotate, and the stirring shaft 11 drives the stirring blades 13 on its circumferential side wall to rotate, so as to stir and crush the soil at the bottom of the treatment barrel 1, and allow it to be fully mixed with the repair liquid sprayed by the liquid spraying assembly.

[0035] like Figure 2 and Figure 3 As shown, the stirring blades 13 of this embodiment are arranged in multiple groups along the axial direction of the stirring shaft 11, and each group of two stirring blades 13 is symmetrically arranged with respect to the axial center line of the stirring shaft 11. Each stirring blade 13 is arranged obliquely with respect to the axial center line of the stirring shaft 11, and the inclination directions of each group of two stirring blades 13 are opposite, and the projections of two adjacent groups of stirring blades 13 on the horizontal plane are in an "X" shape. Preferably, a group of stirring blades 13 closest to the bottom of the treatment barrel 1 abuts against the bottom of the treatment barrel 1, so that the stirring blades 13 of this group can stir the soil at the bottom of the treatment barrel 1. Since each stirring blade 13 is arranged obliquely, when the stirring shaft 11 drives the stirring blade 13 to rotate, the stirring blade 13 applies an upward turning force to the soil, so that the soil at various heights in the treatment barrel 1 can be fully mixed, and the mixing with the repair liquid is also more uniform.

[0036] like Figure 2 and Figure 3 As shown, in this embodiment, a scraper 14 is vertically provided at one end of each stirring blade 13 away from the stirring shaft 11, and one end of the scraper 14 away from the stirring blade 13 abuts against the inner wall of the treatment barrel 1. In this embodiment, the horizontal cross-section of the scraper 14 is a trapezoid, and the scraper 14 will rotate with the stirring shaft 11. The scraper 14 scrapes the inner wall of the treatment barrel 1 to avoid soil accumulation on the inner wall of the treatment barrel 1, effectively preventing the residual soil from agglomerating on the inner wall of the treatment barrel 1 for a long time, so that all the soil can be mixed with the repair liquid, and the subsequent cleaning of the treatment barrel 1 is also easier.

[0037] like Figure 2 and Figure 3As shown, one end of the stirring shaft 11 of this embodiment is connected to the output shaft of the second motor 12, and the other end of the stirring shaft 11 is provided with a spherical boss 15. The spherical boss 15 can prevent the soil in the drum 2 from falling on the end of the stirring shaft 11 and accumulating on the end of the stirring shaft 11.

[0038] The working principle of the utility model is:

[0039] When treating the contaminated soil, first open the movable door 4 of the drum 2 through the locking member, put the contaminated soil into the drum 2, and then re-lock the movable door 4 through the locking member. Start the first motor 5, and while the first motor 5 drives the drum 2 to rotate, use the liquid spraying assembly to spray the repair liquid into the drum 2. These repair liquids will enter the drum 2 through the filter holes 3 on the surface of the drum 2 and mix with the soil in the drum 2. The smaller soil in the drum 2 falls from the filter holes 3 of the drum 2 to the bottom of the treatment drum 1, and the second motor 12 works to drive the stirring shaft 11 and the stirring blades 13 on the stirring shaft 11 to rotate. The soil that falls to the bottom of the treatment drum 1 is stirred by the stirring assembly and discharged through the discharge pipe 6. As the drum 2 rotates driven by the first motor 5, the soil in the drum 2 will continuously roll and break during the rotation of the drum 2, and its position will also continuously change. Due to the infiltration of the repair liquid, the binding force between the soil particles is weakened, and the soil is more easily broken, thereby improving the efficiency of the soil falling from the filter holes 3 of the drum 2, and greatly improving the efficiency of soil screening and processing.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A petroleum hydrocarbon contaminated soil remediation device, characterized in that: The invention comprises a treatment cylinder (1), a rotating cylinder (2), a liquid spraying assembly and a stirring assembly, wherein the top of the treatment cylinder (1) is an open structure, the rotating cylinder (2) is rotatably installed in the treatment cylinder (1), a feed port is provided on the rotating cylinder (2), a movable door (4) that can be opened and closed is installed at the feed port, and contaminated soil is put into the rotating cylinder (2) through the movable door (4), a plurality of filter holes (3) are provided on the cylinder wall of the rotating cylinder (2) and the movable door (4), and a rotating cylinder power source for driving the rotating cylinder (2) to rotate is fixed on the treatment cylinder (1); the liquid spraying assembly is arranged on the top of the treatment cylinder (1) and is located above the rotating cylinder (2) The stirring component is located in the treatment cylinder (1) and below the rotating cylinder (2); the repair liquid sprayed by the liquid spraying component enters the rotating cylinder (2) through the filter holes (3) and is mixed with the contaminated soil in the rotating cylinder (2); the mixed contaminated soil is crushed in the rotating cylinder (2) and filtered out by each of the filter holes (3), and then stirred by the stirring component; a discharge pipe (6) is installed on the treatment cylinder (1); one end of the discharge pipe (6) is connected to the inside of the treatment cylinder (1), and the other end of the discharge pipe (6) is located outside the treatment cylinder (1); the stirred soil is discharged through the discharge pipe (6).

2. The petroleum hydrocarbon contaminated soil remediation device according to claim 1, characterized in that: A plurality of spike portions (7) are evenly arranged on the inner wall of the rotating drum (2) along the circumferential direction.

3. The petroleum hydrocarbon contaminated soil remediation device according to claim 1, characterized in that: The rotating drum (2) is horizontally arranged inside the processing drum (1), that is, the axial center line of the rotating drum (2) is parallel to the horizontal plane.

4. The petroleum hydrocarbon contaminated soil remediation device according to claim 1, characterized in that: The liquid spraying assembly comprises a mounting plate (8), a water delivery plate (9) and a nozzle (10); the water delivery plate (9) is fixed to the top of the treatment cylinder (1) via the mounting plate (8); the water delivery plate (9) is an internal hollow structure; a plurality of nozzles (10) are provided on the lower surface of the water delivery plate (9) facing the rotating cylinder (2); each of the nozzles (10) is connected to the interior of the water delivery plate (9).

5. The petroleum hydrocarbon contaminated soil remediation device according to claim 1, characterized in that: The stirring assembly comprises a stirring power source, a stirring shaft (11) and stirring blades (13); the stirring shaft (11) is rotatably mounted in the treatment barrel (1); the stirring power source is fixed at the bottom of the treatment barrel (1); the output end of the stirring power source is connected to the stirring shaft (11) to drive the stirring shaft (11) to rotate; and a plurality of stirring blades (13) are mounted on the stirring shaft (11).

6. The petroleum hydrocarbon contaminated soil remediation device according to claim 5, characterized in that: Each stirring blade (13) is arranged obliquely with respect to the axial center line of the stirring shaft (11).

7. The petroleum hydrocarbon contaminated soil remediation device according to claim 6, characterized in that: The stirring blades (13) are arranged in multiple groups along the axial direction of the stirring shaft (11), and the two stirring blades (13) in each group are symmetrically arranged about the axial center line of the stirring shaft (11). The two stirring blades (13) in each group are inclined in opposite directions, and the projections of two adjacent groups of stirring blades (13) on the horizontal plane are in an "X" shape.

8. The petroleum hydrocarbon contaminated soil remediation device according to claim 5, characterized in that: A scraper (14) is vertically provided at one end of the stirring blade (13) away from the stirring shaft (11), and one end of the scraper (14) away from the stirring blade (13) abuts against the inner wall of the treatment cylinder (1).

9. The petroleum hydrocarbon contaminated soil remediation device according to claim 5, characterized in that: One end of the stirring shaft (11) is connected to the output end of a stirring power source, and the other end of the stirring shaft (11) is provided with a spherical boss (15).

10. The petroleum hydrocarbon contaminated soil remediation device according to claim 1, characterized in that: One end of the movable door (4) is hinged to the rotating drum (2), and the other end of the movable door (4) is a free end, and the free end is locked with the rotating drum (2) through a locking member; the locking member comprises a protrusion (16) and a bolt (17), the protrusion (16) is fixed to the free end of the movable door (4), and the bolt (17) is threadedly connected to the protrusion (16); a groove is provided on the outer wall of the rotating drum (2) at a position corresponding to the protrusion (16) when the movable door (4) is closed, and a screw hole is provided in the groove at a position corresponding to the bolt (17), the protrusion (16) is embedded in the groove when the movable door (4) is closed, and the bolt (17) is threadedly connected to the screw hole.

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