CN110608149B

CN110608149B - Low-temperature pump

Info

Publication number: CN110608149B
Application number: CN201810611820.2A
Authority: CN
Inventors: 毛文瑞; 王为民; 杜建伟; 徐海波; 林红斌
Original assignee: Shanghai Youtuo Low Temperature Technology Co ltd
Current assignee: Shanghai Youtuo Low Temperature Technology Co ltd
Priority date: 2018-06-14
Filing date: 2018-06-14
Publication date: 2022-02-25
Anticipated expiration: 2038-06-14
Also published as: CN110608149A

Abstract

The invention discloses a cryopump which comprises a connecting flange, a hollow pump body and a refrigerator, wherein the hollow pump body is connected with the flange in a sealing way, the refrigerator is connected with the pump body in a sealing way, the refrigerator comprises a primary cold head and a secondary cold head which extend into a cavity in the hollow pump body, a radiation-proof screen is arranged in the cavity, the lower end of the radiation-proof screen is connected with the primary cold head, an opening is formed in the upper end of the radiation-proof screen, a primary baffle is arranged in the middle of the opening, a condensation adsorption component is arranged on the secondary cold head, a guide plate is arranged on the inner wall of the radiation-proof screen between the condensation adsorption component and the primary baffle, and the condensation adsorption component comprises a heat conduction component and a heat conduction shell, the upper end opening of the heat conduction shell is provided with an accommodating cavity; because condensation adsorption component no longer is multilayer structure, solid-state gas can follow the accumulation of up condensation of condensation adsorption component bottommost, and condensation adsorption component bottom and side all have shelters from, have stopped solid-state gas and have fallen the danger of protecting against radiation and shielding, can guarantee that space internal pressure is more stable.

Description

Low-temperature pump

Technical Field

The invention relates to the technical field of cryopumps, in particular to a cryopump.

Background

A cryopump is a vacuum pump that condenses or adsorbs gases using a cryogenic surface. The cryopump can obtain clean vacuum with the maximum pumping speed and the minimum limiting pressure, and is widely applied to industries such as semiconductors and integrated circuits, vacuum coating, ion implanters, space simulation and the like.

As shown in fig. 1, it is a typical cryopump structure, which includes a flange 1, a primary baffle 2, a radiation shield 3, a cold umbrella 4, a cold head 5 and a refrigerator 6. When the cryopump operates, the refrigerating machine 6 continuously generates cold energy, so that the radiation protection screen 3, the primary baffle 2 and the cold umbrella 4 are kept in a low-temperature state. The refrigerator 6 is divided into a primary cold head and a secondary cold head. The primary cold head of the refrigerating machine 6 is connected with the radiation-proof screen 3 and the primary baffle 2, the temperature is 60-100K usually, and gases such as water vapor and carbon dioxide in the space can be condensed on the surface of the gas. The secondary cold head of the refrigerator 6 is connected with the cold umbrella 4, the temperature is usually 10-20K, gases such as nitrogen, oxygen, argon and the like in the space can be condensed on the surface of the secondary cold head, and non-condensable gases such as hydrogen, helium and the like are adsorbed by activated carbon adhered to the inner surface of the cold umbrella at low temperature. By means of low-temperature condensation, low-temperature adsorption and the like, the cryopump pumps almost all gases in the space to obtain high vacuum.

When the cryopump works, nitrogen, oxygen, argon and other gases enter the cryopump through the opening of the radiation-proof screen 3 and the gap between the first-level baffle plate 4, finally reach the cold umbrella 4 and are cryogenically condensed on the surface of the cold umbrella 4. As shown in fig. 2, the amount of gas condensed on the surface of the cold umbrella is limited because it is difficult for gas molecules to reach the inside of the cold umbrella due to the multi-layered structure of the conventional cold umbrella. When the condensed gas on the surface of the cold umbrella is accumulated continuously, the air pumping speed of the cryopump to the gas is reduced continuously, and the pressure in the space is increased continuously. Finally, the cryopump can reach a saturated state, and the pumping effect cannot meet the requirement. The maximum amount of gas that can be condensed inside the cryopump is referred to as the pumping capacity of the cryopump. After the cryopump is saturated, the cryopump needs to be regenerated to restore its original pumping performance. Regeneration is the process of exhausting the condensed or adsorbed gas from the cryopump through various temperature raising means. The regeneration process of the cryopump may take many hours, and frequent regeneration restricts the use of the cryopump, requiring an increase in pumping capacity of the cryopump. And the solid gas of the cold umbrella surface condensation of this kind of structure, under the too thick condition of condensation layer, also have the danger that drops the radiation protection screen, because the radiation protection screen temperature is higher, solid gas can gasify, and the pressure in the space will rise, and the vacuum degree worsens.

Disclosure of Invention

In view of the above-mentioned shortcomings, the present invention provides a cryopump that has a larger pumping capacity for gases, so that the cryopump can be operated for a longer period of time to reach a saturated state, thereby reducing the regeneration frequency of the cryopump.

In order to achieve the above purpose, the embodiment of the invention adopts the following technical scheme:

the utility model provides a cryopump, the cryopump include flange, with flange sealing connection's the cavity pump body and with pump body sealing connection's refrigerator, the refrigerator is including the one-level cold head and the second grade cold head that stretch into the inside cavity of the cavity pump body, be equipped with the screen of protecting against radiation in the cavity, the screen lower extreme of protecting against radiation links to each other with the one-level cold head and its upper end is equipped with the opening, the opening middle part is equipped with the one-level baffle, be equipped with condensation adsorption component on the second grade cold head, condensation adsorption component with be equipped with the guide plate on the screen inner wall of protecting against radiation between the one-level baffle, condensation adsorption component includes that heat-conducting component and upper end opening have the heat conduction casing that holds the chamber.

In accordance with one aspect of the invention, the thermally conductive assembly includes a central thermally conductive member that is inverted over the secondary cold head and a thermally conductive plate disposed within the receiving cavity.

According to one aspect of the invention, the heat-conducting plates are distributed radially around the central heat-conducting member and circumferentially in the containing chamber, and are connected to the central heat-conducting member and to the bottom of the heat-conducting shell, respectively.

In accordance with one aspect of the invention, the thermally conductive plates are circumferentially distributed around the central thermally conductive member within the receiving cavity and are connected to the bottom of the thermally conductive housing.

According to one aspect of the invention, the heat conducting plate is uniformly distributed around the containing cavity to cut the containing cavity into a plurality of areas and is connected with the bottom of the heat conducting shell.

According to one aspect of the invention, the baffle is a conical structure or a polygonal conical structure.

According to one aspect of the invention, the shape of the upper end opening of the heat conducting shell is matched with the shape of the lower end opening of the flow guide plate.

According to one aspect of the invention, the inner diameter of the upper end opening of the heat-conducting shell is not smaller than the inner diameter of the lower end opening of the deflector.

In accordance with one aspect of the invention, the primary baffle is an annular louver.

According to one aspect of the invention, the deflector is connected to the radiation shield by a fastener.

The implementation of the invention has the advantages that: the cryopump comprises a connecting flange, a hollow pump body in sealing connection with the flange and a refrigerator in sealing connection with the pump body, wherein the refrigerator comprises a primary cold head and a secondary cold head which extend into a cavity in the hollow pump body; the inside one-level baffle that is less than of screen of protecting against radiation is higher than condensation adsorption component part, has installed a guide plate, compares with the cold umbrella structure of multilayer about the tradition, and condensation adsorption component replaces and is similar to the shell structure of dark bucket, and the inside special heat-conducting plate structure of making of condensation adsorption component, then under the water conservancy diversion effect of guide plate, gaseous can reach the inside any position of condensation adsorption component, is become solid-state by the low temperature condensation at condensation adsorption component internal surface. And because the condensation adsorption component no longer is multilayer structure, solid-state gas can follow the accumulation of up condensation of condensation adsorption component bottommost, and condensation adsorption component bottom and side all have shelters from, have stopped solid-state gas and have fallen the danger of protecting against radiation the screen, can guarantee that space internal pressure is more stable.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic diagram of a conventional cryopump in the background of the invention;

FIG. 2 is a schematic diagram of a conventional cryopump condensing in the background of the invention;

fig. 3 is a schematic diagram of a cryopump in accordance with an embodiment of the present invention;

FIG. 4 is a schematic diagram of a cryopump condensing according to an embodiment of the invention;

fig. 5 is a schematic diagram of a cryopump in accordance with an embodiment of the present invention;

fig. 6 is a schematic view of a baffle configuration according to an embodiment of the present invention;

fig. 7-11 are schematic diagrams illustrating the distribution of the heat conducting plates in the condensation-adsorption assembly according to the embodiment of the invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 3 to 11, a cryopump, the cryopump include flange 11, with flange sealing connection's the cavity pump body 1 and with pump body sealing connection's refrigerator 6, refrigerator 6 is including stretching into the one-level cold head 61 and the second grade cold head 62 of the inside cavity of the cavity pump body, be equipped with radiation protection screen 3 in the cavity, radiation protection screen lower extreme links to each other with the one-level cold head and its upper end is equipped with the opening, the opening middle part is equipped with one-level baffle 2, be equipped with condensation adsorption component 4 on the second grade cold head, condensation adsorption component with be equipped with guide plate 7 on the radiation protection screen inner wall between the one-level baffle, condensation adsorption component includes that heat-conducting component and upper end opening have the heat conduction casing 41 that holds the chamber.

In practical application, the heat-conducting assembly comprises a central heat-conducting member 5 which is turned over on the secondary cold head and a heat-conducting plate arranged in the containing cavity.

In practical application, the heat conducting plates are distributed in the accommodating cavity in a radial state around the central heat conducting part and are respectively connected with the central heat conducting part and the bottom of the heat conducting shell.

In practical application, the heat conducting plates are annularly distributed in the accommodating cavity around the central heat conducting piece and are connected with the bottom of the heat conducting shell.

In practical application, the heat-conducting plate winds the heat-conducting plate and is uniformly distributed in the accommodating cavity, the accommodating cavity is cut into a plurality of areas, and the areas are connected with the bottom of the heat-conducting shell.

In practical application, the heat conducting plate can be a plurality of concentric ring combinations, a plurality of fin combinations, a plurality of concentric rings and a plurality of fins combinations, or square grid combinations, or other triangular grid combinations and polygonal grid combinations.

These various forms of heat-conducting plates are intended to facilitate the transfer of cold from the secondary stage of the refrigerator 6 to the solid gas to be condensed, maintaining the cryogenic state of the surface of the solid gas and thus continuously condensing more gas. Since the thermal conductivity of the solid gas is less than the thermal conductivity of the heat-conducting plates, without these heat-conducting plates, the cold is transported in the solid gas and the amount of gas that can be condensed is reduced.

In practical application, the guide plate is in a conical structure or a polygonal conical structure. The guide plate is a conical structure, and can also be a polygonal conical structure. When the guide plate is assembled with the radiation-proof screen, one end of the guide plate with the large diameter is tightly attached to the inner wall of the radiation-proof screen and can be connected together in the form of screws, rivets and the like. The end of the deflector with small diameter needs to face the bottom of the radiation-proof screen.

In practical application, the outer diameter of the guide plate is the same as the inner diameter of the radiation-proof screen, namely, one end of the guide plate with a large caliber is tightly attached to the inner wall of the radiation-proof screen;

the inner diameter d1 of the baffle should not be larger than the diameter d2 of the condensation adsorption module.

Under the condition that the refrigerating power of the refrigerating machine is enough, the diameter of the condensation adsorption component can be made to be very large and even close to the inner diameter of the radiation-proof screen, so that the air extraction capacity of the low-temperature pump is greatly increased.

Besides the function of guiding gas, the guide plate can also protect the condensation adsorption component from heat radiation coming from the inlet of the radiation-proof screen. Because the diameter d2 of the condensation adsorption component is larger than the inner diameter d1 of the guide plate, in actual assembly, the condensation adsorption component is firstly installed on the secondary installation surface of the refrigerator, then the guide plate is installed, and finally the primary baffle is installed.

In practical application, the shape of the upper end opening of the heat conduction shell is matched with the shape of the lower end opening of the guide plate.

In practical application, the inner diameter d2 of the upper end opening of the heat-conducting shell is not smaller than the inner diameter d1 of the lower end opening of the deflector.

In practical application, the primary baffle is an annular louver.

In practical application, the guide plate is connected with the radiation-proof screen through a fastener.

The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention disclosed herein are intended to be covered by the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

1. A low-temperature pump comprises a connecting flange, a hollow pump body connected with the flange in a sealing way and a refrigerator connected with the pump body in a sealing way, wherein the refrigerator comprises a primary cold head and a secondary cold head which extend into the inner cavity of the hollow pump body, it is characterized in that a radiation-proof screen is arranged in the cavity, the lower end of the radiation-proof screen is connected with the primary cold head, an opening is arranged at the upper end of the radiation-proof screen, a primary baffle is arranged in the middle of the opening, a condensation adsorption component is arranged on the secondary cold head, a guide plate is arranged on the inner wall of the radiation-proof screen between the condensation adsorption component and the primary baffle, the condensation adsorption component comprises a heat conduction component and a heat conduction shell with an upper end opening provided with a containing cavity, the upper end opening shape of the heat conduction shell is matched with the lower end opening shape of the guide plate, and the inner diameter of the upper end opening of the heat conduction shell is not smaller than the inner diameter of the lower end opening of the guide plate.

2. The cryopump of claim 1, wherein the conductive assembly includes a central conductive member inverted over the secondary cold head and a conductive plate disposed within the receiving chamber.

3. The cryopump of claim 2, wherein the conductive plates are radially distributed circumferentially around the central member within the cavity and are connected to the central member and the bottom of the conductive housing, respectively.

4. The cryopump of claim 2, wherein the conductive plates are circumferentially distributed about the central conductive member within the cavity and connected to the bottom of the conductive housing.

5. The cryopump of claim 2, wherein the conductive plate is evenly distributed around the cavity to cut the cavity into regions and connected to the bottom of the conductive housing.

6. The cryopump of claim 1, wherein the baffle is a conical structure or a polygonal conical structure.

7. The cryopump of claim 6, wherein the primary baffle is an annular louver.

8. The cryopump of claim 7, wherein the baffle is coupled to the shield by a fastener.