An automatic control device for antifreeze and heat tracing cables for industrial pipelines

Abstract

This invention relates to the field of industrial pipeline technology, and in particular to an automatic control device for antifreeze heat tracing cables in industrial pipelines. The device includes an outer protective ring with a U-shaped bottom on its inner arc surface. A bent inner bushing is located in the middle section of the inner arc surface of the U-shaped bottom. Air holes are spaced along the connection area between the U-shaped bottom and the bent inner bushing. An air inlet groove extends circumferentially along the top of the expansion chamber, allowing the hot air entering the device to diffuse evenly circumferentially, avoiding localized pressure concentration. An air storage chamber is formed between the outer bushing and the U-shaped bottom, and an expansion chamber is formed inside the U-shaped bottom. These two elements can temporarily store and buffer the pressure of the hot air. Simultaneously, the flexible edge of the outer bushing can elastically deform with changes in air pressure within the air storage chamber, absorbing the pressure impact during the initial expansion of the hot air. Through the combination of circumferential air guidance, air storage buffering, and flexible compensation, this device can effectively reduce the risk of bulging, deformation, or sealing failure of the outer protective ring, outer bushing, and sealing connections due to concentrated thermal expansion pressure.

Description

Technical Field

[0001] This invention relates to the field of industrial pipeline technology, and in particular to an automatic control device for antifreeze and heat tracing cables for industrial pipelines. Background Technology

[0002] Industrial pipelines are widely used in petrochemical, coal chemical, natural gas transmission, municipal water supply, fire protection networks, pharmaceutical, food processing, and fluid transmission systems in low-temperature environments. In cold regions or under low-temperature conditions, the medium inside the pipeline is prone to increased viscosity, crystallization, solidification, or even freezing due to the decrease in external temperature. This can affect the efficiency of medium transmission, or even cause pipeline blockage, valve failure, pipe wall rupture, and production system shutdown, among other safety hazards. Therefore, to ensure the stable operation of industrial pipelines in low-temperature environments, it is usually necessary to install anti-freeze heat tracing structures on the outside of the pipeline.

[0003] Among existing methods for preventing freezing of industrial pipelines, electric heat tracing cables are widely used due to their advantages such as flexible installation, rapid heating, and relatively convenient maintenance. The common installation method is to arrange the heat tracing cable along the pipeline axis or spirally wrapped around the outer wall of the pipeline, and then fix it with cable ties, tape, clamps or insulation layers, so that the heat tracing cable can transfer heat to the pipeline, thereby achieving the purpose of pipeline freezing and heat preservation. In order to improve the heat tracing effect, some systems will also be equipped with temperature controllers, temperature sensors or control modules to control the start and stop of the heat tracing cable or adjust the heating power according to the changes in pipeline temperature.

[0004] In practical applications, existing antifreeze heat tracing control devices mostly rely on electronic sensors, controllers, and external electrical actuators to achieve temperature detection and start / stop control. Although this type of solution has high control accuracy, its structure is relatively complex and has high requirements for installation environment, sealing performance, and electrical reliability. In industrial sites with conditions such as water vapor, dust, oil, corrosive media, or strong vibration, poor sensor contact, aging circuits, seal failure, and control component failure may all affect the stable operation of the heat tracing system. Furthermore, when the temperature of the heat tracing area rises, the gas in the confined space expands due to heat. If it cannot be released or buffered in time, it may cause the external sheath, snap-fit ​​parts, or sealing structure to bulge and deform. When the ambient temperature drops, the internal air pressure of the structure decreases, which may cause insufficient adhesion or widening of the sealing gap, affecting the stability of heat transfer between the heat tracing cable and the pipeline. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and propose an automatic control device for antifreeze heat tracing cables for industrial pipelines.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: The device includes an outer protective ring, the inner arc surface of which has a U-shaped bottom, the middle section of the inner arc surface of which has a bent inner bushing, the middle part of the outer arc surface of which has a concave groove, an air hole between the U-shaped bottom and the bent inner bushing, an expansion cavity inside the U-shaped bottom, an air inlet groove at the top of the expansion cavity, the air inlet groove communicating with the air hole, an outer bushing snapped into the concave grooves on both sides of the U-shaped bottom, a first sealing ring between the outer bushing and the concave groove, an air storage cavity formed between the outer bushing and the U-shaped bottom, a retaining ring at the bottom of the outer arc surface of the outer bushing, a bearing assembly connected to the retaining ring, a cylindrical air cap slidably fitted onto the inner arc surface of the bearing assembly, a magnet ring A on the side of the bearing assembly near the air storage cavity, and a magnet ring B that mates with the magnet ring A on the upper end face of the cylindrical air cap.

[0007] Preferably, the surface of the bent inner liner is fitted with an inner protective ring, the inner protective ring including an outer ring and an inner ring, the outer ring of the inner protective ring and the expansion cavity form a sealed cavity, the inner ring of the inner protective ring and the outer ring form a reserved cavity, the surface of the inner ring of the inner protective ring is provided with a protruding conical section, and both the inner and outer protective rings are hollow through structures.

[0008] Preferably, the outer arc surface of the outer bushing is a flexible edge, which can undergo elastic deformation when the gas pressure in the gas storage cavity changes, so as to adjust the gas transmission state between the gas storage cavity and the expansion cavity.

[0009] Preferably, the inner arc surface of the fixed ring is provided with an internal thread, and the outer peripheral surface of the bearing assembly is provided with an external thread that mates with the internal thread. The bearing assembly is fixed inside the fixed ring by a threaded connection.

[0010] Preferably, the inner arc surface of the bearing assembly is provided with a stepped section, and a second sealing gasket is fitted on the stepped section. The second sealing gasket is used to seal the sliding fit between the cylindrical gasket and the bearing assembly.

[0011] Preferably, the magnet ring A is adsorbed and disposed at one end of the bearing assembly near the air storage chamber, and the magnet ring B is embedded in the upper end face of the cylindrical air cover. The magnetic attraction between the magnet ring A and the magnet ring B keeps the cylindrical air cover in a closed position.

[0012] Preferably, the air holes are arranged at intervals along the connection area between the bottom of the U-shaped ring and the bent inner bushing, and the air inlet ring groove extends circumferentially along the top of the expansion cavity, so that a circumferential air guiding channel is formed between the air holes and the expansion cavity.

[0013] Preferably, the sealing cavity is located between the outer ring of the inner protective ring and the expansion cavity, and the sealing cavity is used to form a buffer sealing space when the expansion cavity expands due to heat or contracts due to cold.

[0014] Preferably, the reserved cavity is disposed between the inner ring and the outer ring of the inner protective ring, and the protruding conical segment is disposed circumferentially along the inner ring surface of the inner protective ring.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. By using air holes spaced apart along the connection area between the bottom of the U-shaped ring and the bent inner bushing, and the air inlet ring groove extending circumferentially along the top of the expansion chamber, the hot air entering the device can be evenly diffused circumferentially, avoiding local pressure concentration. An air storage chamber is formed between the outer bushing and the bottom of the U-shaped ring, and an expansion chamber is formed inside the bottom of the U-shaped ring. Both can temporarily store the hot air and buffer the pressure. At the same time, the flexible edge of the outer bushing can elastically deform with the change of air pressure in the air storage chamber, absorbing the pressure impact at the beginning of the hot air expansion. Through the combination of circumferential air guidance, air storage buffering and flexible compensation, this device can effectively reduce the risk of bulging, deformation or sealing failure of the outer protective ring, outer bushing and sealing connection due to thermal expansion pressure concentration.

[0016] 2. A sealed cavity is formed between the outer ring of the inner retaining ring and the expansion chamber. During the process of pressure increase in the expansion chamber and pressure relief by opening the cylindrical gas cover, the sealed cavity can act as an intermediate buffer space to absorb pressure fluctuations, so that the pressure is not instantly transmitted to the outer wall of the pipe and the area where the heat tracing cable is attached. The reserved cavity between the inner and outer rings of the inner retaining ring can provide a margin for the elastic deformation of the inner retaining ring to adapt to the change in outer diameter caused by the thermal expansion or low-temperature contraction of the pipe. Thus, even if the expansion chamber is depressurized, the inner retaining ring can still maintain a stable fit to the pipe, preventing the device from loosening, the heat tracing cable from shifting, or excessive local compression, thereby ensuring the continuity and uniformity of the heat tracing effect.

[0017] 3. The inner ring surface of the inner retaining ring is circumferentially provided with a protruding conical section. After installation, the protruding conical section contacts the outer wall of the industrial pipeline, which can increase the friction and positioning engagement between the inner retaining ring and the pipeline. At the same time, the reserved cavity allows the inner retaining ring to have elastic adaptability during the thermal expansion and contraction of the pipeline. Through the combination of the anti-slip positioning effect of the protruding conical section and the elastic fit of the inner retaining ring, this device can suppress the axial movement or circumferential rotation caused by the operation of the heat tracing cable, the depressurization of the cavity, and the vibration of the pipeline, so that the device can be kept in the predetermined installation position for a long time.

[0018] 4. The hot air generated during the heating process of the heat tracing cable, or the cold air formed at low temperatures, is introduced into the expansion chamber and the air storage chamber through the air holes and air inlet grooves. This allows the chamber pressure to adapt to the working state of the heat tracing cable. Then, through the cooperation between the cylindrical air cover, magnet ring A, and magnet ring B, the chamber pressure automatically opens to release pressure when it rises above the magnetic holding force, and automatically resets and closes after the pressure drops. Thus, the hot and cold air flow generated by the heat tracing cable itself can be used as the driving medium to achieve mechanical automatic pressure regulation control without the participation of an external controller. The structure is simple and suitable for industrial pipeline heat tracing environments such as low temperature and humidity. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the retaining ring of an automatic control device for antifreeze heat tracing cables for industrial pipelines proposed in this invention; Figure 2 This is a schematic diagram of the inner retaining ring structure of an automatic control device for antifreeze heat tracing cables for industrial pipelines proposed in this invention. Figure 3 This is a schematic diagram of the overall side profile of an automatic control device for antifreeze and heat tracing cables for industrial pipelines proposed in this invention. Figure 4 This is a partially enlarged cross-sectional schematic diagram of the outer sheath of an automatic control device for antifreeze and heat tracing cables for industrial pipelines, as proposed in this invention. Figure 5 This is an exploded structural diagram of the cylindrical gas cover of an automatic control device for antifreeze and heat tracing cables for industrial pipelines proposed in this invention. Figure 6 This is a schematic diagram showing the disassembly of the outer bushing of an automatic control device for antifreeze and heat tracing cables for industrial pipelines proposed in this invention. Figure 7 This is a top view schematic diagram of an automatic control device for antifreeze heat tracing cables for industrial pipelines proposed in this invention; Figure 8 For the present invention Figure 3 Enlarged structural diagram at point A in the middle.

[0020] In the diagram: 1. Outer protective ring; 101. U-shaped ring bottom; 102. Bent inner bushing; 103. Concave groove; 104. Air hole; 105. Expansion chamber; 106. Inlet ring groove; 2. Outer bushing; 201. Fixed ring; 3. First sealing ring; 4. Air storage chamber; 5. Bearing assembly; 501. Stepped section; 502. Second sealing gasket; 6. Cylindrical air cap; 7. Magnet ring A; 8. Magnet ring B; 9. Inner protective ring; 10. Sealing chamber; 11. Reserved cavity; 12. Protruding conical section. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0022] The terms used in this invention, such as "upper," "lower," "left," "right," "middle," and "one," are merely for clarity of description and are not intended to limit the scope of the invention. Any changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0023] Reference Figures 1-8An automatic control device for antifreeze and heat tracing cables for industrial pipelines includes an outer sheath 1. The inner arc surface of the outer sheath 1 has a U-shaped ring bottom 101. A bent inner bushing 102 is located in the middle section of the inner arc surface of the U-shaped ring bottom 101. A concave groove 103 is located in the middle of the outer arc surface of the outer sheath 1. An air hole 104 is provided between the U-shaped ring bottom 101 and the bent inner bushing 102. An expansion cavity 105 is provided inside the U-shaped ring bottom 101. An air inlet groove 106 is provided at the top of the expansion cavity 105, and the air inlet groove 106 is connected to the air hole 104. An outer bushing 2 is engaged in the concave grooves 103 on both sides of the U-shaped ring bottom 101. A first sealing ring 3 is provided between the outer bushing 2 and the concave grooves 103. An air storage cavity 4 is formed between the outer bushing 2 and the U-shaped ring bottom 101. A retaining ring 201 is provided at the bottom of the outer arc surface of the outer bushing 2. A bearing assembly 5 is connected to the retaining ring 201. A cylindrical air cover 6 is slidably sleeved on the inner arc surface of the bearing assembly 5. A magnet ring A7 is provided on the side of the bearing assembly 5 near the air storage cavity 4. A magnet ring B8 that cooperates with the magnet ring A7 is provided on the upper end face of the cylindrical air cover 6.

[0024] In the embodiments of the above technical solution, firstly, the outer protective ring 1 serves as the external protection and installation body of the device, and is fitted onto the outside of the industrial pipeline. The inner arc surface of the outer protective ring 1 is provided with a U-shaped ring bottom 101, which is used to form a circumferential support base, so that the device can be stably covered on the outside of the industrial pipeline. The middle section of the inner arc surface of the U-shaped ring bottom 101 is provided with a bent inner bushing 102, which is used to engage with the inner protective ring 9 and form a transition area for gas flow guidance and structural support on the inside of the device.

[0025] A concave groove 103 is provided in the middle of the outer arc surface of the outer protective ring 1, and an outer bushing 2 is snapped into the concave grooves 103 on both sides of the U-shaped ring bottom 101. A first sealing ring 3 is provided between the outer bushing 2 and the concave groove 103. The first sealing ring 3 is used to improve the sealing between the outer bushing 2 and the outer protective ring 1, and to prevent external moisture, dust or impurities from directly entering the device. An air storage cavity 4 is formed between the outer bushing 2 and the U-shaped ring bottom 101. The air storage cavity 4 is used to temporarily store the hot air generated by the heating cable or the cold air flow formed by the cooling inside the device under low temperature conditions.

[0026] After the heat tracing cable is installed, it is located near the outer wall of the industrial pipeline and within the circumferential heat collection area formed by the inner protective ring 9 and the bent inner bushing 102. When the heat tracing cable is powered on, the heat it generates is transferred to the outer wall of the industrial pipeline on the one hand, and heats the air in the circumferential heat collection area on the other hand. Since the outer protective ring 1, the outer bushing 2 and the first sealing ring 3 form a barrier to the outer space, and the inner protective ring 9 forms a close fit and limit to the outer wall of the pipeline, the hot air around the heat tracing cable will not diffuse randomly, but will preferentially accumulate in the circumferential heat collection area. The vent 104 is located near the circumferential heat collection area and communicates with the air inlet ring groove 106. When the air in the circumferential heat collection area is heated by the heat tracing cable, its temperature rises and its volume expands, forming a pressure difference relative to the expansion chamber 105 and the air storage chamber 4. Under the action of this pressure difference, the hot air enters the air inlet ring groove 106 through the vent 104, and is then distributed circumferentially to the expansion chamber 105 and the air storage chamber 4 by the air inlet ring groove 106. Thus, this device does not rely on the natural diffusion of hot air into the cavity without direction, but rather the circumferential heat collection area where the heat tracing cable is located, the vent 104, and the air inlet ring groove 106 together form a restricted flow path, enabling the hot air to participate stably and directionally in the cavity air pressure regulation.

[0027] The preferred technical solution in this embodiment is: Reference Figure 1 , Figure 3 and Figure 4 After the heating cable is started, the air around the heating cable is heated to form hot air. Since there is an air hole 104 between the U-shaped bottom 101 and the bent inner bushing 102, and there is an expansion cavity 105 inside the U-shaped bottom 101, and an air inlet groove 106 is opened at the top of the expansion cavity 105, which is connected to the air hole 104, the hot air generated during the heating process of the heating cable can enter the air inlet groove 106 through the air hole 104, and then be dispersed in the circumferential direction by the air inlet groove 106 into the gas regulation space where the expansion cavity 105 and the gas storage cavity 4 are located. The gas inside the gas storage cavity 4 is not pre-sealed independently, but comes from the hot air generated during the heating process of the heating cable, or the cold air formed inside the device under the action of low external temperature when the heating cable stops heating. These gases can all enter through the air hole 104 and the air inlet groove 106 and participate in the gas pressure regulation.

[0028] When the heat tracing cable is continuously heated, the temperature of the hot air entering the expansion chamber 105 and the air storage chamber 4 rises and expands, causing the internal pressure of the chamber to gradually increase. Since the air holes 104 are arranged at intervals along the connection area between the U-shaped bottom 101 and the bent inner bushing 102, and the air inlet ring groove 106 extends circumferentially along the top of the expansion chamber 105, the hot air will not concentrate on a certain local position, but can diffuse evenly along the air inlet ring groove 106, making the pressure distribution in the expansion chamber 105 more balanced. This structure can reduce the problem of structural bulging or uneven pressure on the heat tracing cable caused by excessive local thermal expansion pressure.

[0029] During the process of pressure increase in the expansion chamber 105, the flexible edge of the outer arc surface of the outer bushing 2 first undergoes a certain degree of elastic deformation. Under the action of air pressure, the flexible edge bulges slightly in the corresponding clearance direction, thereby absorbing part of the thermal expansion pressure in the gas storage chamber 4. This process is equivalent to a first-level buffer for the hot air generated by the heating cable, preventing the instantaneous accumulation of hot air from causing a sudden increase in the chamber pressure. At the same time, the gas storage chamber 4, as a temporary gas containment space, can temporarily store the hot air entering through the air hole 104, so that pressure exchange and pressure balance are formed between the expansion chamber 105 and the gas storage chamber 4.

[0030] When the heating intensity of the heat tracing cable is high, or the local temperature of the pipeline continues to rise, causing the pressure in the expansion chamber 105 and the air storage chamber 4 to increase further, the cylindrical air cover 6 begins to participate in automatic pressure relief and regulation. The bottom of the outer arc surface of the outer bushing 2 is provided with a retaining ring 201, which is connected to a bearing assembly 5. The inner arc surface of the bearing assembly 5 is slidably fitted with the cylindrical air cover 6. The side of the bearing assembly 5 near the air storage chamber 4 is provided with a magnetic ring A7, and the upper end face of the cylindrical air cover 6 is provided with a magnetic ring B8. Under normal conditions, the magnetic ring A7 and the magnetic ring B8 are attracted to each other by magnetic attraction, keeping the cylindrical air cover 6 in a closed position.

[0031] When the air pressure in the expansion chamber 105 and the air storage chamber 4 increases to a certain extent, the air pressure acts on the cylindrical air cover 6 and exerts an outward pushing force on the cylindrical air cover 6. When the air pressure pushing force is greater than the magnetic attraction force between the magnet ring A7 and the magnet ring B8, the cylindrical air cover 6 overcomes the magnetic attraction force and slides along the inner arc surface of the bearing assembly 5, so that the gas channel that was originally closed is opened or partially opened. At this time, the high-pressure hot gas in the expansion chamber 105 and the air storage chamber 4 can be depressurized through this channel, thereby reducing the internal pressure of the cavity and avoiding abnormal deformation of the outer protective ring 1, the outer bushing 2 or the sealing part due to excessive expansion of hot gas.

[0032] Reference Figure 5 and Figure 7 , Figure 8 The inner arc surface of the bearing assembly 5 is provided with a stepped section 501, and a second sealing gasket 502 is fitted on the stepped section 501. The second sealing gasket 502 is used to maintain a sealing fit during the sliding opening and closing of the cylindrical gas cover 6, so that when the cylindrical gas cover 6 is in the closed position, it can effectively block the entry of external water vapor and impurities. When the cylindrical gas cover 6 is pushed open by air pressure to release pressure, the second sealing gasket 502 can also limit the disorderly leakage of gas from unnecessary gaps, so that the gas is released according to the predetermined channel, improving the controllability of the pressure relief process.

[0033] When it is necessary to increase the pressure relief threshold, the bearing assembly 5 is screwed in towards the cylindrical gas cover 6, which reduces the initial distance between the magnet ring A7 and the magnet ring B8 and increases the magnetic attraction between them. At this time, the expansion chamber 105 and the gas storage chamber 4 need to reach a higher air pressure in order to push the cylindrical gas cover 6 to overcome the magnetic attraction and open.

[0034] When it is necessary to lower the pressure relief threshold, rotate the bearing assembly 5 away from the cylindrical gas cover 6 to increase the initial distance between the magnet ring A7 and the magnet ring B8, thereby reducing the magnetic attraction between them. At this time, the lower pressure in the cavity can push the cylindrical gas cover 6 to open and relieve pressure.

[0035] During the depressurization process of expansion chamber 105, an inner retaining ring 9 is snapped onto the surface of the bent inner bushing 102. The inner retaining ring 9 includes an outer ring and an inner ring. A sealing cavity 10 is formed between the outer ring of the inner retaining ring 9 and the expansion chamber 105. When the hot gas in the expansion chamber 105 expands and is ready to depressurize, the gas pressure in the expansion chamber 105 will exert a certain compressive force on the outer ring of the inner retaining ring 9. Since the sealing cavity 10 is located between the outer ring of the inner retaining ring 9 and the expansion chamber 105, the sealing cavity 10 can serve as an intermediate buffer space to absorb the pressure fluctuations before and after the expansion chamber 105 depressurizes.

[0036] Specifically, when the pressure in the expansion chamber 105 increases but has not yet been completely depressurized, the outer ring of the inner retaining ring 9 undergoes a slight elastic deformation under pressure, and the sealing chamber 10 changes volume accordingly. This volume change can temporarily bear part of the pressure in the expansion chamber 105, so that the pressure is not directly and instantaneously transmitted to the outer wall of the pipe and the contact area of ​​the heating cable, thereby avoiding the heating cable being over-compressed and also avoiding hard squeezing between the inner retaining ring 9 and the pipe. When the cylindrical gas cover 6 is opened to depressurize, the pressure in the expansion chamber 105 gradually decreases, and the outer ring of the inner retaining ring 9 gradually rebounds under its own elasticity and the buffering effect of the sealing chamber 10, so that the internal structure of the device is smoothly restored, avoiding the sudden loosening of the inner retaining ring 9 or the instantaneous reduction of the adhesion force due to the sudden drop in pressure. Reference Figure 2 and Figure 6 Therefore, when the expansion chamber 105 is depressurized, the inner protective ring 9 forms an elastic buffer layer through the sealing cavity 10 between the outer ring and the expansion chamber 105. Before depressurization, it bears the extrusion pressure generated by the high-pressure hot gas, slows down the pressure drop rate during the depressurization process, and helps to restore the fit between the device and the pipeline after depressurization. This structure can make the depressurization process of the expansion chamber 105 more stable and avoid the pressure change of the cavity directly affecting the pipeline fixing effect and the bonding effect of the heat tracing cable.

[0037] A reserved cavity 11 is provided between the inner ring and the outer ring of the inner retaining ring 9. When the pressure of the expansion cavity 105 increases and acts on the inner retaining ring 9, the reserved cavity 11 provides deformation space for the inner ring and the outer ring of the inner retaining ring 9, so that the inner retaining ring 9 can elastically make room within a certain range. Especially when the heat tracing cable is continuously heated, the industrial pipeline itself will also undergo thermal expansion, and the outer diameter of the pipeline may increase slightly. At this time, the inner ring of the inner retaining ring 9 can deform slightly towards the outer ring with the help of the reserved cavity 11 to adapt to the change in the outer diameter of the pipeline and avoid the device from clamping the pipeline too tightly. Conversely, when the temperature decreases and the pipeline shrinks, the reserved cavity 11 allows the inner retaining ring 9 to maintain its fit to the outer wall of the pipeline through its own elastic recovery, preventing the device from loosening.

[0038] The inner ring 9 has a protruding conical section 12 on its inner ring surface. The protruding conical section 12 is arranged circumferentially along the inner ring surface of the inner ring 9. After installation, the protruding conical section 12 contacts the outer wall of the industrial pipeline. Since the protruding conical section 12 is a raised structure, it can increase the friction and interlocking effect between the inner ring 9 and the outer wall of the pipeline. When the expansion chamber 105 is depressurized, even if the internal pressure of the chamber changes continuously from rising, releasing and falling, the protruding conical section 12 can still maintain a stable contact between the inner ring 9 and the pipeline, preventing the device from axial movement or circumferential rotation due to pressure fluctuations. At the same time, the protruding conical section 12 can form multi-point or circumferential contact support, making the clamping force distribution of the inner ring 9 on the outer wall of the pipeline more stable.

[0039] In low-temperature environments, when the heating cable stops working or the external cold air lowers the internal temperature of the device, cold air or low-temperature airflow is formed inside the device. This cold air can also enter the air inlet ring groove 106 through the air hole 104 and further enter the expansion chamber 105 and the gas storage chamber 4. As the gas cools and contracts, the internal pressure of the cavity decreases, and the flexible edge of the outer bushing 2 rebounds under its own elasticity. The inner protective ring 9 also adapts and recovers through the cooperation of the reserved cavity 11 and the sealing cavity 10. At this time, the cylindrical gas cover 6 remains closed under the adsorption of the magnetic ring A7 and the magnetic ring B8, preventing external cold air, water vapor and impurities from flowing back into the cavity and ensuring that the gas environment inside the device is relatively stable.

[0040] When the heat tracing cable stops working or the outside temperature drops, the gas temperature in the circumferential heat collection area, expansion chamber 105 and gas storage chamber 4 decreases and shrinks. At this time, the internal pressure of the cavity decreases, and the flexible edge of the outer bushing 2 rebounds slightly towards the inside of the cavity under the action of external pressure and its own elastic restoring force. The sealing cavity 10 between the outer ring of the inner protective ring 9 and the expansion chamber 105 also absorbs part of the pressure change through elastic deformation, thereby providing primary compensation for the negative pressure generated by the shrinkage.

[0041] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An automatic control device for antifreeze and heat tracing cables for industrial pipelines, comprising an outer sheath (1), characterized in that: The outer protective ring (1) has a U-shaped ring bottom (101) on its inner arc surface, a bent inner bushing (102) in the middle section of the inner arc surface of the U-shaped ring bottom (101), and a concave groove (103) in the middle of the outer arc surface of the outer protective ring (1). An air hole (104) is provided between the U-shaped ring bottom (101) and the bent inner bushing (102). An expansion cavity (105) is provided inside the U-shaped ring bottom (101). An air inlet ring groove (106) is provided at the top of the expansion cavity (105). The air inlet ring groove (106) is connected to the air hole (104). An outer bushing (2) is snapped into the concave groove (103) on both sides of the U-shaped ring bottom (101). A first sealing ring (3) is provided between the outer bushing (2) and the concave groove (103). An air storage cavity (4) is formed between the outer bushing (2) and the U-shaped ring bottom (101). The outer bushing (2) has a retaining ring (201) at the bottom of its outer arc surface. The retaining ring (201) is connected to a bearing assembly (5). The inner arc surface of the bearing assembly (5) is slidably fitted with a cylindrical air cap (6). The bearing assembly (5) has a magnet ring A (7) on the side near the air storage chamber (4), and the upper surface of the cylindrical air cover (6) has a magnet ring B (8) that cooperates with the magnet ring A (7).

2. The automatic control device for antifreeze heat tracing cable of industrial pipeline according to claim 1, characterized in that: The surface of the bent inner bushing (102) is fitted with an inner protective ring (9). The inner protective ring (9) includes an outer ring and an inner ring. The outer ring of the inner protective ring (9) forms a sealed cavity (10) with the expansion cavity (105). The inner ring of the inner protective ring (9) forms a reserved cavity (11) with the outer ring. The inner ring surface of the inner protective ring (9) is provided with a protruding cone section (12). The inner protective ring (9) and the outer protective ring (1) are both hollow through structures.

3. The automatic control device for antifreeze heat tracing cable of industrial pipeline according to claim 1, characterized in that: The outer arc surface of the outer bushing (2) is a flexible edge. The flexible edge can undergo elastic deformation when the gas pressure in the gas storage cavity (4) changes, so as to adjust the gas transmission state between the gas storage cavity (4) and the expansion cavity (105).

4. The automatic control device for antifreeze heat tracing cable of industrial pipeline according to claim 1, characterized in that: The inner arc surface of the fixed ring (201) is provided with an internal thread, and the outer circumferential surface of the bearing kit (5) is provided with an external thread that mates with the internal thread. The bearing kit (5) is fixed inside the fixed ring (201) by a threaded connection.

5. The automatic control device for antifreeze heat tracing cable of industrial pipeline according to claim 1, characterized in that: The inner arc surface of the bearing assembly (5) is provided with a stepped section (501), and a second sealing gasket (502) is fitted on the stepped section (501). The second sealing gasket (502) is used to seal the sliding fit between the cylindrical air cover (6) and the bearing assembly (5).

6. The automatic control device for antifreeze heat tracing cable of industrial pipeline according to claim 1, characterized in that: The magnet ring A (7) is attached to one end of the bearing assembly (5) near the air storage chamber (4), and the magnet ring B (8) is embedded in the upper surface of the cylindrical air cover (6). The magnetic attraction between the magnet ring A (7) and the magnet ring B (8) keeps the cylindrical air cover (6) in a closed position.

7. The automatic control device for antifreeze heat tracing cable of industrial pipeline according to claim 1, characterized in that: The air holes (104) are arranged at intervals along the connection area between the U-shaped bottom (101) and the bent inner bushing (102), and the air inlet ring groove (106) extends circumferentially along the top of the expansion cavity (105), so that an circumferential air guiding channel is formed between the air holes (104) and the expansion cavity (105).

8. The automatic control device for antifreeze heat tracing cable of industrial pipeline according to claim 1, characterized in that: The sealing cavity (10) is located between the outer ring of the inner protective ring (9) and the expansion cavity (105). The sealing cavity (10) is used to form a buffer sealing space when the expansion cavity (105) is heated and expanded or cooled and contracted.

9. The automatic control device for antifreeze heat tracing cable of industrial pipeline according to claim 1, characterized in that: The reserved cavity (11) is located between the inner ring and the outer ring of the inner protective ring (9), and the protruding cone segment (12) is arranged circumferentially along the inner ring surface of the inner protective ring (9).

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