Heating system for aerated block production

Abstract

The invention relates to the technical field of aerated block production, and particularly discloses a heating system for aerated block production, which comprises a kettle body, a platform track for transporting aerated blocks is arranged in the kettle body, a steam heat source, a compressed air source and a cold water storage tank are arranged outside the kettle body, and the steam heat source is communicated to the inside of the kettle body through a steam switch. A steam pipeline is arranged in the kettle body, a compressed air source is communicated with the interior of the kettle body through a compressed air switch, a cold water storage tank is communicated with an interlayer in the kettle body through a cooling water valve, and an air outlet switch is communicated with the upper end in the kettle body; the fan, the steam switch, the compressed air switch, the cooling water valve and the air outlet switch are all electrically connected with an external controller. According to the scheme, the problem that in an existing aerated block steam curing system, the four corners of a green body are heated unevenly, and consequently the four corners of an aerated block are broken can be solved.

Description

Technical Field

[0001] The invention relates to the technical field of aerated block production, and in particular to a heating system for aerated block production. Background Art

[0002] Autoclaved aerated concrete blocks have the advantages of light weight, high thermal insulation and good sound insulation, and have become an important component of new building materials. The autoclaving and curing process of autoclaved aerated concrete blocks is a necessary condition for obtaining strength and other properties, which is related to the performance of the products. The autoclaving and curing process consumes a lot of steam, which is also related to the production efficiency and energy consumption.

[0003] A Chinese patent with announcement number CN201920899247.X discloses an aerated concrete autoclave curing device. In the device, although the cooperation between the circulation pipe, the dehumidifier, the fan, the temporary air storage box and the nozzle plays a role in heat flow circulation, improves the autoclave curing efficiency of the aerated concrete, and increases the performance of the aerated concrete; however, in the device, only the moisture in the gas introduced into the curing box is removed, and there is no improvement on the steam curing process and the inside of the kettle body, so there are still disadvantages of large steam consumption and high production cost; and in the actual production process, our company staff found that when the blank is heated, the heating tubes will be evenly placed at the bottom of the blank, but the four corners of the top of the blank will not be heated in place, and the uneven heating will cause the blank to rupture. Therefore, the market currently needs a heating system that can heat the aerated brick blank evenly in the kettle body. Summary of the invention

[0004] The invention provides a heating system for producing aerated blocks, so as to solve the problem that in the existing aerated block steaming system, the four corners of the green body are heated unevenly, resulting in the cracking of the four corners of the aerated blocks.

[0005] To solve the above-mentioned purpose, the technical solution adopted by the present invention is as follows: a heating system for the production of aerated blocks, including a kettle body, a platform track for transporting aerated blocks is arranged in the kettle body, a steam heat source, a compressed air source, and a cold water storage tank are arranged outside the kettle body, the steam heat source is connected to the interior of the kettle body through a steam switch, and a steam pipe is arranged in the kettle body, the compressed air source is connected to the interior of the kettle body through a compressed air switch, the cold water storage tank is connected to the inner interlayer of the kettle body through a cooling water valve, the air outlet switch is connected to the upper end of the interior of the kettle body, and a fan is arranged in the kettle body, and the fan, steam switch, compressed air switch, cooling water valve, and air outlet switch are all electrically connected to the controller of the external device.

[0006] Further, the compressed air switch is connected to a vortex tube through a first three-way valve, the cold end outlet of the vortex tube is connected to the cold water storage tank, and the hot end outlet of the vortex tube is connected to a second three-way valve, and the second three-way valve is connected to the first heat source storage tank and the second heat source storage tank respectively;

[0007] A sealing cavity is horizontally arranged outside the top wall of the kettle body along the length of the kettle body, a double-headed piston is slidingly and sealingly connected in the sealing cavity, the interior of the double-headed piston is hollow, a first one-way valve and a second one-way valve are respectively installed through the side walls at both ends of the double-headed piston, and a third one-way valve is installed through the middle of the double-headed piston, and the first one-way valve and the second one-way valve only allow airflow from the sealing cavity to flow into the double-headed piston;

[0008] The third one-way valve is connected to a ring pipe, and the third one-way valve only allows airflow to flow from the inside of the double-headed piston to the outside of the ring pipe. The ring pipe can slide back and forth on the inner wall of the kettle body. A plurality of through holes are spaced apart along the circumferential direction on the ring pipe, and the lower end of the ring pipe is connected to the steam pipeline;

[0009] The double-headed piston is embedded with a movable bar, which is in a "door" shape, and the lower end of the movable bar extends to the surface of the first one-way valve and the second one-way valve;

[0010] The sealed cavity is connected to the first heat source storage tank through a second pipe, a first solenoid valve is installed in the second pipe, and the sealed cavity is connected to the second heat source storage tank through a third pipe, a second solenoid valve is installed in the third pipe;

[0011] The first three-way valve, the second three-way valve, the first solenoid valve and the second solenoid valve are all electrically connected to the controller.

[0012] Furthermore, the temperature of the steam heat source is 170 to 180°C.

[0013] Furthermore, the pressure of the compressed air source is 0.7 MPa to 1.9 MPa.

[0014] Furthermore, the air flow temperature at the hot end outlet of the vortex tube can reach 170 to 200°C, and the air flow temperature at the cold end outlet can reach -20 to -40°C.

[0015] Furthermore, horizontal slide rails are respectively arranged at the upper and lower ends of the kettle body, and the two slide rails are in a "concave" shape with openings facing each other. The inner wall of the slide rail is a soft rubber strip, and the upper and lower ends of the ring tube are sealed and movably connected through the soft rubber strip.

[0016] The basic principle of this scheme is: after pushing the aerated block to be autoclaved into the kettle body, close the kettle body. First, turn on the compressed air switch, and the first three-way valve is switched to the compressed air switch to directly connect to the inside of the kettle body, so that the pressure inside the kettle body reaches the steam pressure. Then turn on the steam switch, and the steam switch fills the steam pipe with high-temperature steam. At the same time, the first three-way valve is switched to the compressed air switch to connect the vortex tube. After the vortex tube, the compressed air at the hot end outlet enters the second three-way valve, and the controller controls the second three-way valve to connect the first heat source storage tank and the second heat source storage tank at intervals, and the two heat source storage tanks are inflated at intervals, so that the pressure in the two heat source storage tanks is increased to a preset value, and the controller controls the first solenoid valve to open. At this time, the left end of the closed cavity is connected to the first heat source storage tank, and the airflow in the first heat source storage tank rushes into the left side of the double-headed piston, pushing the movable bar to the right relative to the double-headed piston, so that the movable bar touches the left side wall of the double-headed piston to close the first one-way valve, and under the action of the airflow, the double-headed piston as a whole moves to the right in the sealed cavity.

[0017] During the rightward movement, the second one-way valve on the double-headed piston is opened, and the right-side heat source air in the sealed cavity is sucked into the double-headed piston, and the heat source compressed air is delivered to the annular tube through the third one-way valve. The heat source compressed air is mixed with the high-temperature steam in the annular tube and flows out along the through holes on the annular tube. Since the double-headed piston moves horizontally in the kettle body, the gas in the kettle body is evenly mixed under the stirring of the annular tube, and the compressed air mixed steam gas is also evenly distributed in the kettle body.

[0018] When the double-headed piston moves to the right end, the first solenoid valve is closed, and the first heat source storage tank continues to accumulate heat source compressed air. The second solenoid valve is opened, and the heat source compressed air in the second heat source storage tank rushes into the right end of the sealed cavity, and at the same time pushes the movable bar on the double-headed piston to the left, and the second one-way valve is blocked and closed by the movable bar. The movable bar blocked by the surface of the first one-way valve is removed, and the first one-way valve is opened. The heat source compressed air pushes the double-headed piston to move to the left, and the heat source compressed air on the left side of the sealed cavity is sucked into the double-headed piston by the first one-way valve and enters the annular tube along the third one-way valve. During the movement of the annular tube from right to left, the heat source compressed air mixes with the steam heat source and flows out from the through hole of the annular tube, and is evenly distributed over the entire length of the kettle body as the annular tube moves. When the temperature sensor and pressure sensor detect that the pressure and temperature in the kettle reach the preset value, close the second three-way valve. Keep this state for 7 hours.

[0019] While the vortex tube converts the compressed air into heat source compressed air, a cold air flow also flows out of the cold end outlet of the vortex tube, and the cold air flow flows into the cold water storage tank to cool the cooling water in the cold water storage tank.

[0020] After the pressure holding time is reached, the cooling process of the kettle body is started, the fan in the kettle is started and the air outlet switch is turned on, the pressure in the kettle gradually decreases, and the cooling water valve is opened at the same time. The cooling water is passed into the interlayer of the kettle body, exchanges heat with the kettle body, and then returns to the cold water storage tank. When the temperature in the kettle body drops to 70°C and returns to normal pressure, the kettle body can be opened to send out the aerated blocks and carry out the next batch of aerated blocks autoclave process.

[0021] The beneficial effects of this solution are as follows: the compressed air source and the steam heat source are mixed simultaneously through the ring tube and then introduced into the kettle body, ensuring that the pressure and temperature variation range of the air source inside the kettle body is small; the cold and hot air flows in the compressed air source can be diverted through the vortex tube, and the heat source air flow is used to drive the ring tube to reciprocate along the entire length of the kettle body. In the process of the ring tube introducing the mixed air flow, the mixed air flow is ensured to be evenly distributed in the length direction of the kettle body; the cold source air flow of the vortex tube is used for heat exchange with cooling water. When the kettle body needs to be cooled and depressurized subsequently, the cooling water is passed into the kettle body interlayer for heat exchange, ensuring that the compressed air utilization is maximized. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of an embodiment of the present invention;

[0023] Figure 2 It is an enlarged schematic diagram of a double-headed piston in an embodiment of the present invention;

[0024] Figure 3 It is an enlarged schematic diagram of the ring tube in the embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following is further described in detail through specific implementation methods:

[0026] The figure marks in the drawings of the specification include: kettle body 1, platform track 2, aeration block 3, steam switch 4, steam pipe 41, compressed air switch 5, fan 6, first three-way valve 7, second three-way valve 8, vortex tube 9, cold water storage tank 10, first heat source storage tank 11, second heat source storage tank 12, double-headed piston 13, sealed cavity 131, annular tube 14, hollow pipe 141, air outlet switch 15, first one-way valve 161, second one-way valve 162, third one-way valve 163, movable bar 17, support rod 171, cooling water valve 18, slide rail 19, soft rubber strip 20.

[0027] The embodiment is basically as shown in the attached Figure 1 To Attachment Figure 3 As shown:

[0028] A heating system for autoclaved aerated concrete production, comprising an autoclave body 1. A horizontal platform track 2 is arranged at the inner bottom of the body 1, and the platform track 2 is used for the trolley loaded with the green body of autoclaved aerated concrete 3 to enter and exit. A fan 6 is installed in the middle of the side wall of the body 1. The body 1 is connected to an external steam source and a compressed air source through a steam switch 4 and a compressed air switch 5. An air outlet switch 15 is connected to the top of the body 1. A cooling water valve 18 connected to an external cooling water source is installed in the bottom interlayer of the body 1.

[0029] Specifically, the compressed air switch 5 is connected to a vortex tube 9 and a first pipeline through a first three-way valve 7. The first pipeline is directly connected into the body 1. The first three-way valve 7 is connected to the nozzle of the vortex tube 9. The cold end outlet of the vortex tube 9 is connected to an external cold water storage tank 10. The hot end outlet of the vortex tube 9 is connected to a second three-way valve 8. The second three-way valve 8 is respectively connected to a first heat source storage tank 11 and a second heat source storage tank 12. The first heat source storage tank 11 and the second heat source storage tank 12 are respectively connected to an enclosed cavity through a second pipeline and a third pipeline. A first solenoid valve and a second solenoid valve are respectively installed in the second pipeline and the third pipeline. By opening and closing the solenoid valves, the second pipeline and the third pipeline can be controlled to convey airflows into the enclosed cavity respectively.

[0030] The enclosed cavity is horizontally arranged in a tubular shape at the top of the body 1. A double-headed piston 13 is slidably and sealingly connected inside the enclosed cavity. The specific structure of the double-headed piston 13 is as Figure 2 shown. The middle of the double-headed piston 13 is hollow. A first one-way valve 161 and a second one-way valve 162 are respectively installed through both sides of the double-headed piston 13. A third one-way valve 163 is installed through the middle of the double-headed piston 13. Both the first one-way valve 161 and the second one-way valve 162 only allow airflows to enter from the outside of the double-headed piston 13 into the double-headed piston 13. The third one-way valve 163 only allows airflows to flow from the double-headed piston 13 into the annular pipe 14. The third one-way valve 163 is connected to the annular pipe 14. The specific structure of the annular pipe 14 is as Figure 3 shown. The upper and lower ends of the annular pipe 14 are respectively connected to a hollow pipe. Through holes penetrating the outer wall of the annular pipe 14 are spaced along the circumferential direction of the annular pipe 14.

[0031] A through hole is respectively opened on the circumferential wall and the central axis of the double-headed piston 13. An activity bar 17 is slidably connected in the through hole on the circumferential wall. A support rod 171 is slidably connected in the through hole on the central axis. The activity bar 17 is in an inverted "凵" shape, and the support rod 171 is in a straight line shape. Both ends of the support rod 171 can respectively touch the inner walls of both ends of the activity bar 17.

[0032] Horizontal slide rails 19 are installed on the upper and lower inner walls of the kettle body 1, respectively. The two slide rails 19 are in a "concave" shape with openings facing each other. The inner wall of the slide rail 19 adopts a soft rubber strip 20 structure, and the hollow pipe of the ring tube 14 is sealed by the soft rubber strip 20 to ensure that the ring tube 14 can slide back and forth horizontally along the slide rail in the kettle body 1. Specifically, the slide rail 19 at the upper end of the kettle body is arranged parallel to the sealing cavity 131, and the slide rail 19 at the lower end of the kettle body 1 can be installed at the bottom of the inner wall of the steam pipe 41. The steam pipe 41 is made into a hollow pipe with a long notch at the top. The horizontal groove is used for the sliding of the hollow pipe at the lower end of the ring tube, and the sealing soft rubber strip 20 is installed inside and outside the notch along its length to ensure the sealing of the steam pipe 41.

[0033] In this embodiment, the slide rail below the kettle body 1 is a steam pipe 41 , and the steam pipe 41 can be connected through the hollow pipe of the annular pipe 14 , so that the airflow in the steam pipe 41 can enter the inside of the annular pipe 14 along the hollow pipe.

[0034] Pressure sensors and temperature sensors are installed inside the kettle body 1. The pressure sensor, temperature sensor, steam switch 4, compressed air switch 5, air outlet switch 15, cooling water valve 18, first three-way valve 7, second three-way valve 8, first solenoid valve, and second solenoid valve are electrically connected to the external controller. In this embodiment, the pressure of the compressed air source is 1.9MPa. After passing through the vortex tube 9, the air flow at the cold end outlet of the vortex tube 9 can reach -20°C, and the air flow at the hot end outlet of the vortex tube 9 can reach 200°C. The temperature of the steam heat source in this embodiment is 160°C to 175°C. The autoclaving method in this scheme is to first introduce compressed air into the kettle to ensure that the pressure in the kettle is pure steam or close to pure steam pressure, so as to ensure the pressure required for the chemical reaction of the mixture and play a role in preheating the kettle. In order to prevent cracks in the brick due to temperature difference stress, the temperature should be slowly and evenly increased for 1.5h to make the pressure in the kettle reach a gauge pressure of 0.8MPa, and the corresponding temperature in the kettle is about 170°C to 174.5°C. In this embodiment, the gas outlet switch 15 can be a safety valve or a pressure switch to ensure that the pressure in the kettle is stable, and during the entire autoclave process, steam can be continuously introduced into the kettle to keep the temperature constant. Keep it constant for 7 hours at this temperature, so that the active calcium oxide in the lime has enough time to react chemically with the silicon dioxide in the fly ash to generate the required hydrated calcium tridate gel to bind the fly ash particles and achieve the required strength. Then, the steam in the kettle can be released evenly and slowly for 1.5 hours to prevent the blocks from cracking due to temperature difference stress caused by excessive cooling. The autoclave curing cycle is 10.5 hours. When the steam pressure in the kettle drops to zero pressure and its temperature is below 70°C, the kettle door can be opened to take out the bricks. If a steam pressure of 1.0MPa to 1.2MPa gauge pressure is used to cure the blocks, the constant temperature time can be greatly shortened, and the required strength can be achieved in 4.5h to 6h, which also greatly improves the utilization rate of the autoclave.

[0035] In order to improve the utilization rate of the steam and compressed air discharged from the air outlet, multiple kettle bodies 1 can be set, and the autoclaving work of multiple kettle bodies 1 is staggered, and the air outlet switch 15 is connected to the compressed air switch 5 of other kettle bodies 1 through a pipeline. For example, the steam and compressed air discharged from the air outlet of the previous kettle body 1 are passed through the external water vapor separation device, and then recycled to the vortex tube 9 of the next kettle body 1 through the external pressurizing device, and after the cold and hot air flows are separated, they are applied to the autoclaving work of the next kettle body 1.

[0036] The specific implementation process is as follows:

[0037] After pushing the aerated block 3 to be autoclaved into the kettle body 1, close the kettle body 1. First, open the compressed air switch 5, and switch the first three-way valve 7 to the compressed air switch 5 to directly connect to the inside of the kettle body 1, so that the pressure inside the kettle body 1 reaches the steam pressure. Then turn on the steam switch 4, and the steam switch 4 continuously fills the steam pipe 41 with high-temperature steam. During the autoclaving process, the gas outlet switch 15 is opened to ensure that the pressure in the kettle body is balanced and within a safe range. At the same time, switch the first three-way valve 7 to the compressed air switch 5 to connect to the vortex tube 9. After the action of the vortex tube 9, the compressed air at the hot end outlet enters the second three-way valve 8. The controller controls the second three-way valve 8 to connect the first heat source storage tank 11 and the second heat source storage tank 12 at intervals, and inflate the two heat source storage tanks at intervals. After the pressure in the two heat source storage tanks rises to the preset value, the controller controls the first solenoid valve to open. At this time, the left end of the closed cavity is connected to the first heat source storage tank 11, and the airflow in the first heat source storage tank 11 rushes into the double-headed piston. The left side of 13, pushes the movable bar 17 to the right relative to the double-headed piston 13, so that the movable bar 17 touches the left side wall of the double-headed piston 13 to close the first one-way valve 161, and the left end inner wall of the movable bar 17 touches the left end of the support rod 171, driving the support rod 171 to move right relative to the double-headed piston 13, and the right end of the support rod 171 touches the right end inner wall of the movable bar 17, and the second one-way valve 162 is continuously opened. Under the action of the airflow of the first heat source storage tank 11, the double-headed piston 13 as a whole moves to the right in the sealing cavity 131.

[0038] During the rightward movement, the second one-way valve 162 on the double-headed piston 13 is in an open state, and the right-side heat source air in the sealed cavity 131 is sucked into the double-headed piston 13, and the heat source compressed air is delivered to the annular tube 14 through the third one-way valve 163. The heat source compressed air is mixed with the high-temperature steam in the annular tube 14 and flows out along the through holes on the annular tube 14. Since the double-headed piston 13 moves horizontally in the kettle body 1, the gas in the kettle body 1 is evenly mixed under the stirring of the annular tube 14, and the compressed air mixed with the steam gas is also evenly distributed in the kettle body 1.

[0039] When the double-headed piston 13 moves to the right end, the first solenoid valve is closed, and the first heat source storage tank 11 continues to accumulate heat source compressed air. The second solenoid valve is opened, and the heat source compressed air in the second heat source storage tank 12 rushes into the right end of the sealed cavity 131, and at the same time pushes the movable bar 17 on the double-headed piston 13 to the left, and the second one-way valve 162 is blocked and closed by the movable bar 17. The movable bar 17 blocked by the surface of the first one-way valve 161 is removed, and the first one-way valve 161 is opened. The heat source compressed air pushes the double-headed piston 13 to move left, and the heat source compressed air on the left side of the sealed cavity 131 is sucked into the double-headed piston 13 by the first one-way valve 161, and enters the annular tube 14 along the third one-way valve 163. During the movement of the annular tube 14 from right to left, the heat source compressed air mixes with the steam heat source and flows out from the through hole of the annular tube 14, and is evenly distributed over the entire length of the kettle body 1 as the annular tube 14 moves. When the temperature sensor and the pressure sensor detect that the pressure and temperature in the autoclave have reached the preset values, the second three-way valve 8 is closed. This state is maintained for 7 hours.

[0040] While the vortex tube 9 converts the compressed air into heat source compressed air, a cold air flow also flows out of the cold end outlet of the vortex tube 9 , and the cold air flow flows into the cold water storage tank 10 to cool the cooling water in the cold water storage tank 10 .

[0041] After the pressure holding time is reached, the cooling process of the kettle body 1 is started, the fan 6 in the kettle is started and the air outlet switch 15 is turned on, the pressure in the kettle gradually decreases, and the cooling water valve 18 is opened at the same time. The cooling water is passed into the interlayer of the kettle body 1 and returns to the cold water storage tank 10 after heat exchange with the kettle body 1. When the temperature in the kettle body 1 drops to 70°C and returns to normal pressure, the kettle body 1 can be opened, the aerated blocks 3 are sent out, and the next batch of aerated blocks 3 are steam-pressed.

[0042] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A heating system for the production of aerated blocks, characterized in that: It includes a kettle body, which is provided with a platform track for transporting aerated blocks, a steam heat source, a compressed air source and a cold water storage tank are arranged outside the kettle body, the steam heat source is connected to the inside of the kettle body through a steam switch, and a steam pipeline is arranged in the kettle body, the compressed air source is connected to the inside of the kettle body through a compressed air switch, the cold water storage tank is connected to the inner interlayer of the kettle body through a cooling water valve, the air outlet switch is connected to the upper end of the inside of the kettle body, and a fan is arranged in the kettle body, and the fan, steam switch, compressed air switch, cooling water valve and air outlet switch are all electrically connected to the controller of the external device.

2. A heating system for aerated block production according to claim 1, characterized in that: The compressed air switch is connected to a vortex tube through a first three-way valve, the cold end outlet of the vortex tube is connected to a cold water storage tank, and the hot end outlet of the vortex tube is connected to a second three-way valve, and the second three-way valve is connected to the first heat source storage tank and the second heat source storage tank respectively; A sealing cavity is horizontally arranged outside the top wall of the kettle body along the length of the kettle body, a double-headed piston is slidingly and sealingly connected in the sealing cavity, the interior of the double-headed piston is hollow, a first one-way valve and a second one-way valve are respectively installed through the side walls at both ends of the double-headed piston, and a third one-way valve is installed through the middle of the double-headed piston, and the first one-way valve and the second one-way valve only allow airflow from the sealing cavity to flow into the double-headed piston; The third one-way valve is connected to a ring pipe, and the third one-way valve only allows airflow to flow from the inside of the double-headed piston to the outside of the ring pipe. The ring pipe can slide back and forth on the inner wall of the kettle body. A plurality of through holes are spaced apart along the circumferential direction on the ring pipe, and the lower end of the ring pipe is connected to the steam pipeline; The double-headed piston is embedded with a movable bar, which is in a "door" shape, and the lower end of the movable bar extends to the surface of the first one-way valve and the second one-way valve; The sealed cavity is connected to the first heat source storage tank through a second pipe, a first solenoid valve is installed in the second pipe, and the sealed cavity is connected to the second heat source storage tank through a third pipe, a second solenoid valve is installed in the third pipe; The first three-way valve, the second three-way valve, the first solenoid valve and the second solenoid valve are all electrically connected to the controller.

3. A heating system for aerated block production according to claim 2, characterized in that: The temperature of the steam heat source is 170-180°C.

4. A heating system for aerated block production according to claim 3, characterized in that: The pressure of the compressed air source is 0.7MPa-1.9MPa.

5. A heating system for aerated block production according to claim 4, characterized in that: The air flow temperature at the hot end outlet of the vortex tube can reach 170 to 200° C., and the air flow temperature at the cold end outlet can reach -20 to -40° C.

6. A heating system for aerated block production according to claim 5, characterized in that: The upper and lower ends of the kettle body are respectively provided with horizontal slide rails, the two slide rails are in a "concave" shape with openings facing each other, the inner wall of the slide rail is a soft rubber strip, and the upper and lower ends of the ring tube are sealed and movably connected through the soft rubber strip.

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