Low-temperature phase change heating device

Abstract

The low-temperature phase change heating device comprises a heat pipe, a heater and a heat insulation sleeve, the heat pipe is sequentially in contact with a primary cold head and a secondary cold head in a low-temperature pump body from top to bottom and penetrates through an air cylinder shell of the low-temperature pump body, and the height of the heat pipe is continuously decreased from top to bottom; the heater is located outside the low-temperature pump body and makes contact with the heat pipe, and the heat insulation sleeve is arranged on the outer side of the heat pipe and the heater in a sleeving mode. Ice crystals in the heat pipe move in the heat pipe through gravity, so that working fluid in the heat pipe can still perform phase change heat conduction after being solidified, and the heat conduction efficiency of the heat pipe at low temperature is greatly improved; the heat insulation sleeve is used for heat insulation of the heat pipe and the heater, and heat exchange between the heat pipe and the outside is reduced when the low-temperature pump adsorbs the heat pipe at low temperature and the low-temperature pump heats up.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of cryogenic pumps, especially a low-temperature phase change heating device. BACKGROUND

[0002] A cryogenic pump is a storage type vacuum pump, which is provided with an extremely low-temperature surface inside the pump, can capture gas through condensation and adsorption, and can realize an ultra-high vacuum state. The cryogenic pump can obtain a clean vacuum with the maximum pumping speed and the lowest limit pressure, and is widely used in the research and production of semiconductors and integrated circuits, as well as in the fields of molecular beam research, vacuum coating equipment, vacuum surface analysis instruments, ion implanters, and space simulation devices.

[0003] When the cryogenic pump is operated for a long time to reach the saturation capacity, the pumping speed sharply decreases, at which time the pump needs to be stopped and heated to release the gas adsorbed on the low-temperature plate and restore the original pumping performance. The heating and pumping of the pre-pump to remove the condensed and adsorbed gas is called "regeneration".

[0004] There are several ways of regeneration as follows:

[0005] ① Natural heating method: turn off the power of the refrigerator, and use the heat of the pump wall to slowly heat the cryogenic pump. At the beginning, the temperature rises very slowly, when the pressure in the pump rises to the point where the convective heat transfer works, the temperature rising rate increases, and finally reaches a stable temperature value.

[0006] ② Gas heating method: after stopping the refrigerator, open the gas valve to put clean and dry air into the cryogenic pump to quickly heat the low-temperature plate

[0007] ③ Electric heating method: an electric heater is installed on the first and second stage cold head of the cryogenic pump, and the electric heater is powered to heat the low-temperature plate quickly during regeneration, shortening the regeneration time.

[0008] The existing electric heating method uses a metal shell electric heating rod to penetrate into the interior of the cryogenic pump, and the interior of the hollow metal shell is provided with a plurality of electric heating wires and silica gel. The silica gel is located between the electric heating wires and the metal shell to prevent the electric heating wires from contacting each other or the heating rod shell, thereby preventing short circuit.

[0009] The smaller the thickness of the silica gel, the better the heat conduction performance, but the electric heating rod is more likely to short circuit, thereby causing electromagnetic interference. The greater the thickness of the silica gel, the less likely the short circuit occurs, but the heat conduction performance is poorer. Because the silica gel has poor heat conductivity, and the existing electric heating rod has a large thickness of silica gel, the heating amount of the electric heating rod on the cold head cannot be continuously improved, and the time for electric heating regeneration is long. Moreover, due to the priority of the internal space of the cryogenic pump and the demand for reducing the number of sealed interfaces, the number of heating rods cannot be increased to improve the heating amount. UTILITY MODEL CONTENTS

[0010] The utility model provides a low temperature phase change heating device, solved above technical problem.

[0011] A low temperature phase change heating device, comprising: a heat pipe, a heater and a heat insulation sleeve, the heat pipe is in contact with a primary cold head and a secondary cold head inside a low temperature pump body from top to bottom and passes through the cylinder shell of the low temperature pump body, the height of the heat pipe is continuously reduced from top to bottom, the heater is located outside the low temperature pump body and is in contact with the heat pipe, and the heat insulation sleeve is sleeved outside the heat pipe and the heater.

[0012] Further, the heat pipe comprises a pipe body, the pipe body is closed at both ends, the pipe body is filled with working fluid, and the pipe body passes through the cylinder shell and is fixedly connected with the cylinder shell.

[0013] The included angle between the heat pipe and the horizontal plane is greater than 45 degrees.

[0014] Further, the heat pipe comprises a non-stick coating, the non-stick coating is located on the inner side of the pipe body and is attached to the inner wall of the pipe body, and the non-stick coating is fixedly connected with the pipe body.

[0015] Further, the pipe body is made of aluminum, copper, aluminum alloy or copper alloy, and the non-stick coating is a polytetrafluoroethylene coating.

[0016] Further, the working fluid in the pipe body has a melting point lower than -100 DEG C and a critical temperature higher than 0 DEG C.

[0017] Further, the working fluid is ethanol, R23, R508B or R600a.

[0018] Further, the part of the heat pipe extending out of the low temperature pump body is formed with a flat plate part, the heater is in contact with and fixedly connected with the flat plate part, and the heater is an electric heater.

[0019] Further, the heat insulation sleeve is a hard shell, the heat insulation sleeve is fixedly connected with the cylinder shell, the heat insulation sleeve does not contact the heat pipe and the heater, and a vacuum environment is formed in the heat insulation sleeve.

[0020] Further, the heat insulation sleeve is a flexible sleeve with an open end, and an adhesive is arranged at the opening of the heat insulation sleeve.

[0021] Further, the utility model also comprises a first fixing device and a second fixing device, the first fixing device fixes the heat pipe with the primary cold head, and the second fixing device fixes the heat pipe with the secondary cold head.

[0022] The utility model has the following advantages:

[0023] 1. Ice crystals in the heat pipe move by gravity in the heat pipe, so that the working fluid in the heat pipe can still phase change heat conduction after solidification, greatly improving the heat conduction efficiency of the heat pipe at low temperature;

[0024] 2. The heat pipe and the heater are heat insulated by the heat insulation sleeve, reducing the heat exchange between the heat pipe and the outside when the heat pipe is adsorbed at low temperature and heated by the low temperature pump;

[0025] 3. The heat pipe is used for heat conduction, so that the heater is located outside the low temperature pump body, so that a heater with larger area and power can be arranged, the heat to the cold head in unit time is increased, the regeneration time is reduced, and the production efficiency is improved;

[0026] 4. The heater is outside the low temperature pump body, and there is enough space between the heater and the heat pipe for insulation treatment, avoiding the short circuit of the heating rod in the prior art affecting the normal work of the low temperature pump, and improving the reliability of the low temperature pump;

[0027] 5. The heat pipe and the heater can adopt an insulation layer with large thickness or the heater can adopt an insulation shell, and the heat pipe is not powered, avoiding the electromagnetic interference of the short circuit in the prior art on the equipment inside and outside the pump. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed to be used in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only one embodiment of the present application, and for those skilled in the art, other drawings can be obtained on the basis of the provided drawings without creative labor.

[0029] Figure 1 : The low temperature pump is a three-dimensional structure schematic diagram;

[0030] Figure 2 : The low temperature pump is a three-dimensional structure schematic diagram of removing part components;

[0031] Figure 3 : The present application is a cross-sectional structure schematic diagram after installing the low temperature pump;

[0032] Figure 4 : The cross-sectional structure schematic diagram of the present application;

[0033] Figure 5 : Figure 4 The cross-sectional structure schematic diagram of A-A in the middle;

[0034] Figure 6 : Figure 4 The local enlarged view of B in the middle. DETAILED DESCRIPTION

[0035] The utility model will be further described below in combination with the drawings and examples:

[0036] The embodiments of the utility model are described in detail below, and examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are only used to explain the utility model and cannot be understood as limiting the utility model.

[0037] In the description of the utility model, it should be pointed out that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected, it can be directly connected, or indirectly connected through intermediate medium. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to specific circumstances.

[0038] In the description of the utility model, it should be understood that the orientation or position relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and is not indicative or implicit of the device or element indicated must have a particular orientation, a particular orientation and operation, therefore, it cannot be understood as limiting the utility model.

[0039] As Figures 1 to 6 Indicated, a low-temperature phase change heating device, comprising: heat pipe 2, heater 3 and heat insulation sleeve 8, the heat pipe 2 is sequentially contacted with primary cold head 14 and secondary cold head 15 inside low-temperature pump 1 from top to bottom and passes through the cylinder shell 10 of low-temperature pump 1, the heat pipe 2 is continuously reduced from top to bottom height, the heater 3 is located outside low-temperature pump 1 and is contacted with heat pipe 2, the heat insulation sleeve 8 is sleeved on the outside of heat pipe 2 and heater 3.

[0040] Preferably, the inner wall of the heat pipe 2 is smooth without capillary structure, and the friction between the solidified working fluid (ice crystal) and the heat pipe 2 is minimized as much as possible.

[0041] Optionally, a heat pipe 2 is used to contact with the primary cold head 14 and the secondary cold head 15 simultaneously, as Figure 2 And Figure 3 Indicated.

[0042] Optionally, a plurality of heat pipes 2 are used, and a heat pipe 2 is only contacted with one of the primary cold head 14 and the secondary cold head 15, which is not shown in the figure.

[0043] Further, the heat pipe 2 comprises a pipe body 20, the pipe body 20 is closed at both ends, the pipe body 20 is filled with working fluid, and the pipe body 20 penetrates through the cylinder shell 10 and is fixedly connected with the cylinder shell 10. The heat pipe 2 and the cylinder shell 10 are sealed.

[0044] Further, the included angle between the heat pipe 2 and the horizontal plane is greater than 45 degrees, so that the ice crystals are more easily fallen.

[0045] Preferably, the heat pipe 2 is welded with the cylinder shell 10.

[0046] Further, the heat pipe 2 comprises a non-stick coating 22, the non-stick coating 22 is located on the inner side of the pipe body 20 and is attached to the inner wall of the pipe body 20, and the non-stick coating 22 is fixedly connected with the pipe body 20. The non-stick coating 22 is used to reduce the friction between the ice crystals formed by the solidification of the working fluid and the inner wall of the heat pipe 2, so as to avoid the ice crystals being stuck in the middle of the heat pipe 2 and not continuing to slide downward.

[0047] Preferably, the non-stick coating 22 is fixed on the inner wall of the pipe body 20 by existing processes such as electroplating, evaporation, sintering and coating.

[0048] Further, the pipe body 20 is made of aluminum, copper, aluminum alloy or copper alloy, and the non-stick coating 22 is made of polytetrafluoroethylene coating.

[0049] Further, the melting point of the working fluid in the pipe body 20 is lower than -100℃ and the critical temperature is higher than 0℃.

[0050] Further, the working fluid is ethanol, R23, R508B or R600a.

[0051] Further, the part of the heat pipe 2 extending out of the cryogenic pump 1 is formed with a flat plate part 21, the heater 3 is in contact with and fixedly connected with the flat plate part 21, and the heater 3 is an electric heater. The flat plate part 21 increases the surface area, thereby increasing the contact area with the heater 3. The flat plate part 21 has a larger heat conduction amount per unit time, so that the heater 3 matched therewith can adopt a larger heating power.

[0052] Optionally, the heat pipe 2 is fixedly connected with the primary cold head 14 by brazing, and the heat pipe 2 is fixedly connected with the secondary cold head 15 by brazing.

[0053] Optionally, the first fixing device 4 and the second fixing device 5 are further included, the first fixing device 4 fixes the heat pipe 2 with the primary cold head 14, and the second fixing device 5 fixes the heat pipe 2 with the secondary cold head 15.

[0054] Preferably, the first fixing device 4 and the second fixing device 5 can adopt fixing blocks (such as Figure 2 and Figure 3The fixing block is fixedly connected with the cold head by a screw, and the clamp tightly clamps the cold head and the heat pipe 2 inside the clamp to make them contact with each other.

[0055] Preferably, a heat-conducting material such as silicone grease is used to fill the small gaps between the heat pipe 2 and the first fixing device 4 and the second fixing device 5.

[0056] Optionally, the heat insulation sleeve 8 is a hard shell, the heat insulation sleeve 8 is fixedly connected with the cylinder shell 10, the heat insulation sleeve 8 does not contact the heat pipe 2 and the heater 3, and a vacuum environment is formed inside the heat insulation sleeve 8. The heat insulation sleeve 8 has good heat insulation effect, but when the heat insulation sleeve 8 is installed in the cryogenic pump 1 later, it needs to be vacuumized and fixed, and the requirements for the installation equipment and process are higher.

[0057] Optionally, the heat insulation sleeve 8 is a flexible sleeve with one end open, and an adhesive is arranged at the opening of the heat insulation sleeve 8. The flexible sleeve is convenient for closely adhering to the heat pipe 2 and the heater 3 to discharge the air therebetween. When installed, the heat insulation sleeve 8 and the cylinder shell 10 are fixed and sealed by using the adhesive. The heat insulation sleeve 8 is simple to install, but the heat insulation effect is not as good as that of the heat insulation sleeve 8 using a vacuum environment. The heat insulation sleeve 8 is made of existing heat insulation materials, such as aerogel flexible heat insulation felt.

[0058] Preferably, the heat insulation sleeve 8 is made of a metal material, and the heat insulation sleeve 8 and the cylinder shell 10 are fixedly connected by welding.

[0059] Further, a reflective layer 85 is fixedly arranged on the inner wall of the heat insulation sleeve 8.

[0060] Preferably, the reflective layer 85 is a silver plating layer.

[0061] When working, the outer shell 11 needs to be located above the cylinder shell 10, the temperature inside the cryogenic pump 1 is lowered, and the cold screen 12 and the cold umbrella 13 adsorb the molecules in the gas in a low-temperature state. During the working process, the working fluid in the heat pipe 2 will freeze into ice crystals due to the excessively low temperature of the cryogenic pump 1. The ice crystals will slide downward along the heat pipe 2 under the action of gravity until reaching the outside of the cylinder shell 10 (entering the flat plate part 21 in the case of the flat plate part 21). Since the vacuum environment in the heat insulation sleeve 8 blocks the heat exchange between the heat pipe 2 and the outside, the influence of the temperature outside the cryogenic pump 1 on the inside is reduced, so that the cold screen 2 and the cold umbrella 3 inside the cryogenic pump 1 can be successfully lowered to the specified temperature.

[0062] When regenerating: the heater 3 heats the flat plate part 21, and the heat melts the ice crystals and then vaporizes or sublimates them. The vaporized working fluid moves to the contact position of the heat pipe 2 and the primary cold head 14 and the secondary cold head 15, and liquefies or sublimates at the contact position. The heat-released working fluid or the transformed ice crystals move downward along the heat pipe 2 to the flat plate part 21 under the action of gravity to continue to absorb heat, completing the phase change cycle of the heat pipe.

[0063] The heat pipe 2 smoothly changes phase to conduct heat after the working fluid solidifies, greatly improving the heat conduction efficiency, so that a large amount of heat can be transferred to the primary cold head 14 and the secondary cold head 15 in a short time, rapidly heating the primary cold head 14 and the secondary cold head 15, and shortening the regeneration time. After that, according to the detection of the temperature sensor inside the cryogenic pump 1, when the specified temperature is reached, the heater 3 stops working.

[0064] It should be noted that the cryogenic pump 1 is a cryogenic pump of the prior art, which can be the cryogenic pump disclosed in the Chinese Utility Model Patent with the publication number CN117489563B. The primary cold head 14 and the secondary cold head 15 of the cryogenic pump 1 are respectively located inside the cylinder shell 10 and the outer shell 11, and the cylinder shell 10 and the outer shell 11 are fixedly connected. The cold screen 2 and the cold umbrella 3 of the cryogenic pump body 1 are arranged inside the outer shell 11, and the end of the cylinder shell 10 is fixed to the base through the cold head base 16.

[0065] The above has described the present application by way of example, but the present application is not limited to the above specific embodiments, and any modification or variation made based on the present application falls within the scope of the present application.

Claims

1. A low temperature phase change heating device, characterized by, The utility model relates to a low temperature pump, which comprises a heat pipe (2), a heater (3) and a heat insulation sleeve (8), the heat pipe (2) is in contact with a primary cold head (14) and a secondary cold head (15) inside a low temperature pump body (1) from top to bottom and passes through a cylinder shell (10) of the low temperature pump body (1), the heat pipe (2) is continuously reduced in height from top to bottom, the heater (3) is located outside the low temperature pump body (1) and is in contact with the heat pipe (2), and the heat insulation sleeve (8) is sleeved outside the heat pipe (2) and the heater (3). The heat pipe (2) comprises a pipe body (20), the pipe body (20) is closed at both ends, the pipe body (20) is filled with working fluid, and the pipe body (20) passes through and is fixedly connected with the cylinder shell (10); 2. A low temperature phase change heating device according to claim 1, characterised in that: The heat pipe (2) is greater than 45 degrees with the horizontal plane. The heat pipe (2) comprises a non-stick coating (22), the non-stick coating (22) is located inside the pipe body (20) and is attached to the inner wall of the pipe body (20), and the non-stick coating (22) is fixedly connected with the pipe body (20).

3. A low temperature phase change heating device according to claim 2, wherein: The pipe body (20) is made of aluminum, copper, aluminum alloy or copper alloy, and the non-stick coating (22) is made of polytetrafluoroethylene coating.

4. A low temperature phase change heating device according to claim 3, wherein: The working fluid in the pipe body (20) has a melting point lower than -100 DEG C and a critical temperature higher than 0 DEG C.

5. A low temperature phase change heating device according to claim 2, wherein: The working fluid is ethanol, R23, R508B or R600a.

6. A low temperature phase change heating device according to claim 5, wherein: The part of the heat pipe (2) extending out of the low temperature pump body (1) is provided with a flat plate portion (21), the heater (3) is in contact with and fixedly connected with the flat plate portion (21), and the heater (3) is an electric heater.

7. The low temperature phase change heating device of claim 1, wherein: The heat insulation sleeve (8) is a hard shell, the heat insulation sleeve (8) is fixedly connected with the cylinder shell (10), the heat insulation sleeve (8) is not in contact with the heat pipe (2) and the heater (3), and a vacuum environment is formed in the heat insulation sleeve (8).

8. The low temperature phase change heating device of claim 1, wherein: The heat insulation sleeve (8) is a flexible sleeve with an open end, and an adhesive is arranged at the open end of the heat insulation sleeve (8).

9. The low temperature phase change heating device of claim 1, wherein: The utility model also comprises a first fixing device (4) and a second fixing device (5), the first fixing device (4) fixes the heat pipe (2) with the primary cold head (14), and the second fixing device (5) fixes the heat pipe (2) with the secondary cold head (15).

10. The low temperature phase change heating device of claim 1, wherein: ​

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