A heat insulation device in a pump for pumping high-temperature media

Abstract

The present invention discloses an internal heat insulation device for pumping high-temperature media, which is arranged on a centrifugal pump. An insulation chamber and a sealing chamber are sequentially arranged between the pump chamber and the motor. The insulation chamber includes an insulation chamber body connected to the pump chamber and an insulation chamber cover buckled onto the insulation chamber body. A central tube for passing the pump shaft is provided in the center of the insulation chamber, and a throttling sleeve with thermal expansion, insulation and wear-resistant properties is provided between the central tube and the pump shaft. The sealing chamber includes a sealing chamber tube, one end of which is connected to the insulation chamber cover, and the other end of which is connected to the sealing chamber cover. A mechanical seal is provided between the center of the sealing chamber cover and the pump shaft, and the sealing chamber cover is also provided with an automatic exhaust mechanism connected to the sealing chamber. The use of the internal heat insulation device for pumping high-temperature media of the present invention can effectively reduce the temperature of the mechanical seal in the centrifugal pump, improve the reliability of the mechanical seal and reduce the cooling cost.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid pumping equipment, and in particular to a heat insulation device inside a pump for pumping high-temperature media. Background Art

[0002] The multistage centrifugal pump of prior art is as follows Figure 3 As shown, there are multi-stage impellers 2 in the pump chamber 1, which pressurize the medium at multiple levels to achieve high head. The mechanical seal 13 of this pump is set on the pump cover 33, and a mechanical seal that can withstand high pressure is used to ensure the sealing effect. At the same time, the medium conveyed between the dynamic and static rings of the mechanical seal ensures the cooling and lubrication of the mechanical seal. Although the mechanical seal can ensure the cooling and lubrication of the mechanical seal directly through the conveying medium, when the temperature of the conveying medium is very high (such as 180°C), the rubber parts and friction pairs in the existing mechanical seal can no longer work normally in such a high temperature operating environment. Even if the mechanical seal material is replaced, there is a great risk of leakage. If a separate cooling and lubrication circulation device for the mechanical seal is added, the cost and maintenance costs will be very high. The Chinese patent document with the publication date of April 8, 2022 and the publication number CN216241462U discloses a cooling structure for a high-temperature pump seal, including: a shaft assembly, a pump cover, a seal, a seal pressure cover, and an inner circulation sleeve. The shaft assembly includes: a main shaft and a sleeve. The sleeve is mounted on the outside of the main shaft, the pump cover is mounted on the left side of the sleeve, and the seal is mounted on the right side of the sleeve. A pump chamber is formed between the seal, the pump cover and the sleeve. The seal pressure cover is mounted on the outside of the seal and mounted on the right side of the sleeve. The seal pressure cover is respectively provided with a flushing inlet and a flushing outlet, and the flushing outlet is connected to the pump chamber. The inner circulation sleeve is provided between the flushing inlet and the seal. A plurality of liquid inlet holes spaced apart from each other are provided on the outer periphery of the inner circulation sleeve. The low-temperature medium is evenly distributed into the seal through the plurality of liquid inlet holes spaced apart from each other to cool the seal. This high-temperature pump seal cooling structure utilizes an internal circulation jacket to evenly direct the cooling medium around the static and dynamic rings, creating a multi-point flushing structure. This prevents the generation of air at the top of the seal cooling cavity, which can occur with single-point flushing, thereby ensuring effective cooling. However, this high-temperature pump seal cooling structure, which requires an internal circulation jacket to evenly direct the cooling medium around the static and dynamic rings for cooling, incurs high costs and maintenance requirements. Summary of the Invention

[0003] The purpose of the present invention is to solve the problems in the prior art that when the medium temperature is very high, the mechanical seal cannot be cooled down, there is a risk of leakage, and the cooling structure cost and maintenance cost of the mechanical seal of the high-temperature pump of the prior art are very high. An internal heat insulation device for pumping high-temperature medium is provided, which can effectively reduce the temperature of the mechanical seal in the centrifugal pump, improve the reliability of the mechanical seal and reduce the cooling cost.

[0004] The specific technical solution adopted by the present invention to achieve the above-mentioned purpose is: a heat insulation device in a pump for pumping high-temperature media, which is arranged on a centrifugal pump. The centrifugal pump includes a pump chamber and an impeller arranged in the pump chamber. The motor arranged outside the pump chamber is connected to the impeller through a pump shaft. An insulation chamber and a sealing chamber are sequentially arranged between the pump chamber and the motor. The insulation chamber includes an insulation chamber body connected to the pump chamber and an insulation chamber cover buckled on the insulation chamber body. A central tube for passing the pump shaft is provided in the center of the insulation chamber, and a throttling sleeve with thermal expansion and heat insulation and wear resistance properties is provided between the central tube and the pump shaft; the sealing chamber includes a sealing chamber cylinder, one end of the sealing chamber cylinder is connected to the insulation chamber cover, and the other end of the sealing chamber cylinder is connected to the sealing chamber cover. A mechanical seal is arranged between the center of the sealing chamber cover and the pump shaft, and the sealing chamber cover is also provided with an automatic exhaust mechanism connected to the sealing chamber. The present invention provides an insulating chamber and a sealed chamber between the pump chamber and the motor. A mechanical seal is mounted on the sealed chamber cover of the sealed chamber. The sealed chamber cylinder, the insulating chamber cover, and the sealed chamber cover enclose a sealed chamber. The insulating chamber body and the insulating chamber cover (equivalent to the pump cover) enclose an insulating chamber. Thus, the mechanical seal of the present invention comprises an independently operated sealed chamber that is relatively isolated from the pump chamber, separated by an insulating chamber. The provision of the insulating chamber significantly reduces heat conduction from the high-temperature pump chamber to the sealed chamber. The only significant heat conduction pathway between the two is through the medium passage formed between the throttle sleeve and the pump shaft. The medium passes through this passage and fills the sealed chamber, lubricating and cooling the mechanical seal. An automatic exhaust mechanism is used to exhaust any medium vapor that may be present in the sealed chamber, preventing vapor accumulation from reducing the fluid medium in the sealed chamber and affecting the lubrication and cooling of the mechanical seal. The material of the throttle sleeve of the present invention exhibits thermal expansion, thermal insulation, and wear resistance properties, i.e., it expands when heated, exhibits excellent wear resistance, and exhibits excellent thermal insulation properties. After the throttle sleeve expands due to heat, the fitting clearance between the throttle sleeve and the pump shaft becomes very small. When the pressure difference between the sealing chamber and the pump chamber is stable, only a small amount of high-temperature medium passes through the gap to reach the sealing chamber. The heat-insulating characteristics of the throttle sleeve also make the static heat conduction between the sealing chamber and the pump chamber through the channel very small. At the same time, the wear-resistant characteristics of the throttle sleeve also ensure that the throttle sleeve is almost undamaged after the throttle sleeve expands and rubs against the pump shaft, thereby extending the service life of the equipment. In this way, the present invention solves the problems in the prior art that when the medium temperature is very high, the mechanical seal cannot be cooled, there is a risk of leakage, and the cooling structure cost and maintenance cost of the high-temperature pump mechanical seal in the prior art are very high. With limited cost increase, the medium temperature allowed for the pump to operate is greatly increased.

[0005] Preferably, the sealing chamber cylinder is thermally insulated and sealed to the insulation chamber cover and the sealing chamber cover. A thermally insulated sealing sleeve is provided between the outer periphery of the connection section of the sealing chamber cylinder and the insulation chamber cover and the sealing chamber cover. Since the insulation chamber cover effectively serves as the upper cover of the pump chamber, the thermally insulated and sealed connection between the sealing chamber cylinder, the insulation chamber cover, and the sealing chamber cover can reduce the transfer of heat from the pump chamber to the insulation chamber cover through the sealing chamber cylinder, thereby reducing the temperature increase of the mechanical seal provided on the sealing chamber cover. The thermally insulated sealing sleeve is made of a non-metallic material with good thermal insulation properties.

[0006] Preferably, the sealed chamber tube, the heat-insulating chamber cover, and the sealed chamber cover all have equal wall thicknesses, with the sealed chamber tube wall thickness being less than half the thickness of the heat-insulating chamber cover and the sealed chamber cover body. This reduces heat transfer from the pump chamber to the sealed chamber cover through the sealed chamber tube. Typically, the sealed chamber tube wall thickness is 30-45% of the thickness of the heat-insulating chamber cover or the sealed chamber cover body.

[0007] Preferably, the central tube is disposed on the insulation cavity cover of the insulation cavity, a connection hole is provided in the center of the insulation cavity, the lower end of the central tube is disposed within the connection hole, and a sealing ring is provided between the central tube and the connection hole. The central tube of the present invention extends through the entire insulation cavity, thereby ensuring that the medium can enter the sealed cavity from the pump cavity through the central tube. The sealing ring provided between the central tube and the connection hole prevents the medium from entering the insulation cavity.

[0008] Preferably, the insulation cavity cover protrudes upward in a truncated cone shape, and a plurality of fins extend radially outward from the periphery of the central tube. The axial width of the fins gradually decreases from the central tube outward, forming a triangular shape. The fins disposed on the periphery of the central tube dissipate heat from the central tube. The fins of the present invention have a greater axial width (in the axial direction of the central tube) near the central tube and gradually decrease outward, forming a triangular shape, which facilitates better heat dissipation.

[0009] Preferably, two screw plugs are installed on the side walls of the insulation cavity and the pump cavity. A sealing ring is provided between the screw plugs and the side walls of the insulation cavity or pump cavity. The screw plugs on the insulation cavity are used to introduce a cooling medium such as air, which removes heat and cools the insulation cavity, thereby lowering the temperature of the sealed cavity. Alternatively, other cooling media with better cooling effects can be connected externally to further cool the cavity, depending on the actual situation. The main function of the screw plug on the pump cavity is to facilitate draining and regular cleaning of the pump cavity.

[0010] Preferably, the throttle sleeve is made of polytetrafluoroethylene-filled carbon fiber. There are two throttle sleeves in the center tube, one at the upper and lower ends of the center tube. A convex ring is provided in the middle of the center tube to separate the two throttle sleeves. One end of the throttle sleeve abuts against the end face of the convex ring, and the other end of the throttle sleeve is fixed to the two ends of the center tube through a hole with an elastic retaining ring. A cavity is formed between the convex ring and the pump shaft. Polytetrafluoroethylene-filled carbon fiber has the characteristics of thermal expansion, heat insulation, and wear resistance (self-lubrication), which can meet the requirements of the present invention for the throttle sleeve. The throttle sleeve is divided into two parts, upper and lower, and the convex ring is used in the middle of the center tube to separate the upper and lower throttle sleeves. In this way, an annular cavity is formed between the convex ring in the middle of the center tube and the pump shaft. The medium in the cavity is in direct contact with the center tube, which can play a certain heat dissipation role through the center tube, thereby reducing the temperature of the medium flow between the upper throttle sleeve and the pump shaft.

[0011] Preferably, the volume of the insulation chamber is equivalent to that of the sealing chamber, and the sum of the volumes of the insulation chamber and the sealing chamber is not less than the volume of the pump chamber. Even if the insulation chamber and the sealing chamber are separately provided, if the volumes of the insulation chamber and the sealing chamber are too small, the heat dissipation effect may not meet the requirements of long-term continuous operation of the mechanical seal. Tests have shown that when the sum of the volumes of the insulation chamber and the sealing chamber is not less than the volume of the pump chamber, the use of the insulation chamber and the sealing chamber structure can meet the lubrication and heat dissipation requirements of the mechanical seal.

[0012] Preferably, the automatic exhaust mechanism includes a bend pipe, one end of which is screwed to the sealing chamber cover through a connector, and the other end of the bend pipe is provided with an automatic exhaust valve. During high-speed operation of the pump, the mechanical seal generates heat due to friction, so that part of the medium in the medium cavity will vaporize, thereby increasing the pressure in the sealing chamber and reducing the medium, resulting in insufficient lubrication and cooling of the mechanical seal valve; an automatic exhaust valve is provided on the sealing chamber, which will promptly discharge the generated gas. After the gas is discharged, the pressure in the sealing chamber will decrease, and the medium in the pump chamber can enter the sealing chamber through the gap between the throttling sleeve and the pump shaft to replenish it, thereby ensuring lubrication and cooling of the mechanical seal. When the pressure between the sealing chamber and the pump chamber is balanced, the small gap between the throttling sleeve and the pump shaft will hinder the convection between the high-temperature medium in the pump chamber and the low-temperature medium in the sealing chamber, thereby ensuring that the sealing chamber is at a relatively low temperature.

[0013] Preferably, the motor is fixed to the sealing chamber cover through a motor seat and a pull rod, and the motor is connected to the pump shaft with a mechanical seal extending from the upper end through a half coupling. The mechanical seal is a container-type mechanical seal, which is screwed to the sealing chamber cover.

[0014] The beneficial effect of the present invention is that it effectively solves the problems in the prior art centrifugal pumps that when the medium temperature is very high, the mechanical seal cannot be cooled, there is a risk of leakage, and the cooling structure cost and maintenance cost of the mechanical seal of the prior art high-temperature pump are very high. The use of the internal heat insulation device of the present invention for pumping high-temperature media can effectively reduce the temperature of the mechanical seal in the centrifugal pump, improve the reliability of the mechanical seal and reduce the cooling cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a structural cross-sectional view of the heat insulation device of the present invention;

[0016] Figure 2 It is a structural cross-sectional view of a centrifugal pump with the heat insulation device of the present invention;

[0017] Figure 3 It is a structural sectional view of a centrifugal pump in the prior art.

[0018] In the figure, 1. pump chamber, 2. impeller, 3. motor, 4. pump shaft, 5. insulation chamber, 6. sealing chamber, 7. insulation chamber body, 8. insulation chamber cover, 9. center tube, 10. throttling sleeve, 11. sealing chamber tube, 12. sealing chamber cover, 13. mechanical seal, 14. insulation sealing sleeve, 15. connecting hole, 16. sealing ring, 17. heat sink, 18. screw plug, 19. sealing ring, 20. convex ring, 21. elastic circlip for hole, 22. elbow, 23. connector, 24. automatic exhaust valve, 25. motor base, 26. pull rod, 27. half coupling, 28. base, 29. drain screw plug assembly, 30. base, 31. pump barrel, 32. positioning sleeve for shaft, 33. pump cover. DETAILED DESCRIPTION

[0019] The specific implementation of the technical solution of the present invention will be further described below through examples and in conjunction with the accompanying drawings.

[0020] In such Figure 1 In the embodiment 1 shown, a heat insulation device for pumping high temperature medium is provided on a centrifugal pump (see Figure 2 The centrifugal pump comprises a pump chamber 1 and an impeller 2 disposed therein. The pump chamber is enclosed by a base 30, a pump barrel 31, and a heat-insulating chamber 7. The base is mounted on a pedestal 28 and is also provided with a drain plug assembly 29. A motor 3, mounted above the pump chamber, is connected to the impeller via a pump shaft 4. A shaft locating sleeve 32 is provided at the junction of the pump shaft and the impeller. The motor is secured to the seal chamber cover via a motor base 25 and a tie rod 26. The motor is connected to the pump shaft, which has a mechanical seal extending from its upper end, via a half-coupling 27. The mechanical seal is a cartridge-type seal, which is threaded to the seal chamber cover.

[0021] Between the pump chamber and the motor, an insulating chamber 5 and a sealed chamber 6 are sequentially provided. The insulating chamber comprises an insulating chamber body 7 connected to the pump chamber and an insulating chamber cover 8 fastened to the insulating chamber body. A central tube 9, for the pump shaft to pass through, is located in the center of the insulating chamber. The central tube is mounted on the insulating chamber cover. A connecting hole 15 is located in the center of the insulating chamber body, and the lower end of the central tube is positioned within the connecting hole. A sealing ring 16 is positioned between the central tube and the connecting hole. This central tube extends throughout the insulating chamber, ensuring that the medium from the pump chamber passes through the central tube and enters the sealed chamber. The sealing ring between the central tube and the connecting hole prevents the medium from entering the insulating chamber. The insulating chamber cover is convex and truncated. Several cooling fins 17 extend radially outward from the outer periphery of the central tube. The axial width of the cooling fins gradually decreases from the inner periphery of the central tube to form a triangular shape. The fins provide heat dissipation from the inner periphery of the central tube. The axial width of the cooling fins is larger near the inner periphery of the central tube and gradually decreases outward, forming a triangular shape. This facilitates better heat dissipation.

[0022] A throttle sleeve 10, featuring thermal expansion, insulation, and wear resistance, is installed between the center tube and the pump shaft. The throttle sleeve is made of polytetrafluoroethylene-filled carbon fiber. Two throttle sleeves are located at the upper and lower ends of the center tube. A raised ring 20 is located in the center of the center tube to separate the two throttle sleeves. One end of the throttle sleeve abuts the end face of the raised ring, while the other end is secured to the two ends of the center tube via a circlip 21 through a hole. A cavity is formed between the raised ring and the pump shaft. Polytetrafluoroethylene-filled carbon fiber exhibits thermal expansion, insulation, and wear resistance (self-lubricating) properties, meeting the requirements of the present invention for a throttle sleeve. The throttle sleeve is divided into two, upper and lower sections, separated by a raised ring in the center of the center tube. This creates an annular cavity between the raised ring in the center of the center tube and the pump shaft. The medium within this cavity is in direct contact with the center tube, dissipating heat through the center tube and reducing the temperature of the medium flowing between the upper throttle sleeve and the pump shaft.

[0023] The sealed chamber includes a sealed chamber tube 11, one end of which is connected to the heat-insulating chamber cover, and the other end of which is connected to the sealed chamber cover 12. A mechanical seal 13 is provided between the center of the sealed chamber cover and the pump shaft. The sealed chamber cover is also provided with an automatic exhaust mechanism connected to the sealed chamber. The automatic exhaust mechanism includes a bend 22, one end of which is screwed to the sealed chamber cover via a connector 23, and the other end of the bend is provided with an automatic exhaust valve 24. During high-speed operation of the pump, the mechanical seal generates heat due to friction, which causes some of the medium in the medium chamber to vaporize, thereby increasing the pressure in the sealed chamber and reducing the medium, resulting in insufficient lubrication and cooling of the mechanical seal valve. The automatic exhaust valve is provided on the sealed chamber to promptly exhaust the generated gas. After the gas is exhausted, the pressure in the sealed chamber will decrease, and the medium in the pump chamber can enter the sealed chamber through the gap between the throttle sleeve and the pump shaft to replenish it, thereby ensuring lubrication and cooling of the mechanical seal. When the pressure between the sealing chamber and the pump chamber is balanced, the small gap between the throttle sleeve and the pump shaft will hinder the convection between the high-temperature medium in the pump chamber and the low-temperature medium in the sealing chamber, thereby ensuring that the sealing chamber is at a relatively low temperature state.

[0024] The sealing chamber barrel, the insulation chamber cover, and the sealing chamber cover all feature an insulated and sealed connection. A thermally insulating sealing sleeve 14 is positioned between the outer periphery of the connection section of the sealing chamber barrel and the insulation chamber cover and the sealing chamber cover. Since the insulation chamber cover effectively serves as the upper cover of the pump chamber, the thermally insulating and sealed connection between the sealing chamber barrel, the insulation chamber cover, and the sealing chamber cover reduces the transfer of heat from the pump chamber to the insulation chamber cover through the sealing chamber barrel, thereby increasing the temperature of the mechanical seal provided on the sealing chamber cover. The insulation sealing sleeve is made of a non-metallic material with excellent thermal insulation properties; in this embodiment, it is made of polytetrafluoroethylene. The sealing chamber barrel, insulation chamber cover, and sealing chamber cover all have equal wall thicknesses, with the sealing chamber barrel wall thickness being less than half the thickness of the insulation chamber cover and the sealing chamber cover body. The wall thickness of the sealing chamber tube is less than half the thickness of the insulation chamber cover and the sealing chamber cover body, which can reduce the heat of the pump chamber transferred to the sealing chamber cover through the sealing chamber tube. Usually, the wall thickness of the sealing chamber tube is 30-45% of the thickness of the insulation chamber cover or the sealing chamber cover body; in this embodiment, the insulation chamber cover and the sealing chamber cover have the same wall thickness, and the wall thickness of the sealing chamber tube is 40% of the thickness of the insulation chamber cover or the sealing chamber cover body.

[0025] In this embodiment, screw plugs 18 are provided on the side walls of the insulation cavity and the pump cavity. There are two screw plugs on each of the insulation cavity and the pump cavity, and a sealing ring 19 is provided between the screw plug and the side wall of the insulation cavity or the pump cavity. The function of the screw plug on the insulation cavity is to introduce a cooling medium such as air, which removes heat and cools the insulation cavity, thereby reducing the temperature of the sealed cavity. Other cooling media with better cooling effects can also be connected externally to further cool it according to actual conditions. The main function of the screw plug on the pump cavity is to facilitate customers to drain water and regularly clean the pump cavity. In this embodiment, the volume of the insulation cavity is equivalent to that of the sealed cavity, and the sum of the volumes of the insulation cavity and the sealed cavity is not less than the volume of the pump cavity. Even if a heat-insulating chamber and a sealing chamber are provided separately, if the volume of the heat-insulating chamber and the sealing chamber is too small, the heat dissipation effect still cannot meet the requirements of long-term continuous operation of the mechanical seal. After experimental verification, when the sum of the volume of the heat-insulating chamber and the sealing chamber is not less than the volume of the pump chamber, the structure of the heat-insulating chamber and the sealing chamber can meet the lubrication and heat dissipation requirements of the mechanical seal.

[0026] The present invention provides an insulating chamber and a sealed chamber between the pump chamber and the motor. A mechanical seal is mounted on the sealed chamber cover of the sealed chamber. The sealed chamber cylinder, the insulating chamber cover, and the sealed chamber cover enclose a sealed chamber. The insulating chamber body and the insulating chamber cover (equivalent to the pump cover) enclose an insulating chamber. Thus, the mechanical seal of the present invention comprises an independently operated sealed chamber that is relatively isolated from the pump chamber, separated by an insulating chamber. The provision of the insulating chamber significantly reduces heat conduction from the high-temperature pump chamber to the sealed chamber. The only significant heat conduction pathway between the two is through the medium passage formed between the throttle sleeve and the pump shaft. The medium passes through this passage and fills the sealed chamber, lubricating and cooling the mechanical seal. An automatic exhaust mechanism is used to exhaust any medium vapor that may be present in the sealed chamber, preventing vapor accumulation from reducing the fluid medium in the sealed chamber and affecting the lubrication and cooling of the mechanical seal. The material of the throttle sleeve of the present invention exhibits thermal expansion, thermal insulation, and wear resistance properties, i.e., it expands when heated, exhibits excellent wear resistance, and exhibits excellent thermal insulation properties. After the throttle sleeve expands due to heat, the fitting clearance between the throttle sleeve and the pump shaft becomes very small. When the pressure difference between the sealing chamber and the pump chamber is stable, only a small amount of high-temperature medium passes through the gap to reach the sealing chamber. The heat-insulating characteristics of the throttle sleeve also make the static heat conduction between the sealing chamber and the pump chamber through the channel very small. At the same time, the wear-resistant characteristics of the throttle sleeve also ensure that the throttle sleeve is almost undamaged after the throttle sleeve expands and rubs against the pump shaft, thereby extending the service life of the equipment. In this way, the present invention solves the problems in the prior art that when the medium temperature is very high, the mechanical seal cannot be cooled, there is a risk of leakage, and the cooling structure cost and maintenance cost of the high-temperature pump mechanical seal in the prior art are very high. With limited cost increase, the medium temperature allowed for the pump to operate is greatly increased.

[0027] In addition to the above-mentioned embodiments, within the scope disclosed in the claims and description of the present invention, the technical features or technical data of the present invention can be reselected and combined to form new embodiments. These can be achieved by those skilled in the art without creative work. Therefore, these embodiments that are not described in detail in the present invention should also be regarded as specific embodiments of the present invention and within the scope of protection of the present invention.

Claims

1. A heat insulation device for pumping high-temperature media, provided on a centrifugal pump, the centrifugal pump comprising a pump chamber and an impeller disposed within the pump chamber, a motor disposed outside the pump chamber connected to the impeller via a pump shaft, and characterized in that: An insulating chamber and a sealing chamber are provided between the pump chamber and the motor in sequence. The insulating chamber includes an insulating chamber body connected to the pump chamber and an insulating chamber cover buckled on the insulating chamber body. A central tube for passing the pump shaft is provided in the center of the insulating chamber. A throttling sleeve with thermal expansion, insulating and wear-resistant properties is provided between the central tube and the pump shaft. The sealing chamber includes a sealing chamber cylinder. One end of the sealing chamber cylinder is connected to the insulating chamber cover, and the other end of the sealing chamber cylinder is connected to the sealing chamber cover. A mechanical seal is provided between the center of the sealing chamber cover and the pump shaft. Sealing, the sealing chamber cover is also provided with an automatic exhaust mechanism connected to the sealing chamber, the central tube is arranged on the insulation chamber cover of the insulation chamber, a connecting hole is provided in the center of the insulation chamber, the lower end of the central tube is arranged in the connecting hole, a sealing ring is provided between the central tube and the connecting hole, the insulation chamber cover is upwardly protruding in a frustum shape, a plurality of heat sinks are radially extended outward from the outer periphery of the central tube, the axial width of the heat sink gradually decreases from the central tube to the outside to form a triangle, the volume of the insulation chamber is equivalent to the volume of the sealing chamber, and the sum of the volume of the insulation chamber and the volume of the sealing chamber is not less than the volume of the pump chamber.

2. The heat insulation device in a pump for pumping high-temperature media according to claim 1, characterized in that: The sealing cavity tube is thermally insulated and sealed to the thermal insulation cavity cover and the sealing cavity cover. A thermal insulation sealing sleeve is provided between the outer periphery of the connecting section of the sealing cavity tube and the thermal insulation cavity cover and the sealing cavity cover.

3. The heat insulation device in a pump for pumping high-temperature media according to claim 1, characterized in that: The sealing cavity tube, the heat-insulating cavity cover and the sealing cavity cover are all of equal wall thickness structure, and the wall thickness of the sealing cavity tube is less than half of the thickness of the heat-insulating cavity cover and the sealing cavity cover body.

4. The heat insulation device in a pump for pumping high-temperature media according to claim 1, characterized in that: The side walls of the heat-insulating cavity and the pump cavity are both provided with screw plugs. There are two screw plugs on each of the heat-insulating cavity and the pump cavity. A sealing ring is provided between the screw plug and the side wall of the heat-insulating cavity or the pump cavity.

5. The heat insulation device in a pump for pumping high-temperature media according to claim 1, characterized in that: The throttling sleeve is made of polytetrafluoroethylene filled carbon fiber. There are two throttling sleeves in the center tube, which are respectively arranged at the upper and lower ends of the center tube. A convex ring is provided in the middle of the center tube for separating the two throttling sleeves. One end of the throttling sleeve abuts against the end face of the convex ring, and the other end of the throttling sleeve is fixed to the two ends of the center tube through a hole with an elastic retaining ring. A cavity is formed between the convex ring and the pump shaft.

6. The heat insulation device in a pump for pumping high-temperature media according to claim 1, characterized in that: The automatic exhaust mechanism includes a bent pipe, one end of which is screwed to the sealing chamber cover through a connector, and the other end of which is provided with an automatic exhaust valve.

7. The heat insulation device in a pump for pumping high-temperature media according to claim 1, characterized in that: The pump cavity is composed of a base, a pump barrel and a heat-insulating cavity.

8. The heat insulation device in a pump for pumping high-temperature media according to any one of claims 1 to 7, characterized in that: The motor is fixed to the sealing chamber cover through a motor seat and a pull rod. The motor is connected to the pump shaft with a mechanical seal extending from the upper end through a half coupling. The mechanical seal is a cartridge mechanical seal, which is screwed to the sealing chamber cover.

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