CN217763968U

CN217763968U - GM refrigerator

Info

Publication number: CN217763968U
Application number: CN202221508300.7U
Authority: CN
Inventors: 杜希阳; 梁志炜; 艾青; 冯苌春
Original assignee: Hydrogen Technology Guangzhou Co ltd
Current assignee: Hydrogen Technology Guangzhou Co ltd
Priority date: 2022-06-16
Filing date: 2022-06-16
Publication date: 2022-11-08
Anticipated expiration: 2032-06-16

Abstract

The utility model discloses a GM refrigerator, which comprises a primary cold head and a secondary cold head connected with one end of the primary cold head, wherein the secondary cold head comprises a secondary cylinder and a secondary piston positioned in the secondary cylinder; a cold end filling area is arranged in the secondary piston, a first cold accumulation substance is filled in the cold end filling area, and the first cold accumulation substance is gadolinium oxysulfide pellets; the gadolinium oxysulfide pellets are porous pellets, and liquid helium can be stored in the pores of the porous pellets during operation; the diameter of the gadolinium oxysulfide pellet is d, and the value range of d is as follows: d is more than or equal to 0.25mm and less than or equal to 0.8mm. The GM refrigerator adopts gadolinium oxysulfide pellets with a porous structure as a cold storage material, and the heat exchange efficiency of the gadolinium oxysulfide pellets is improved through infiltration of liquid helium. The pressure drop of liquid helium flowing through the gadolinium oxysulfide pellets is reduced by increasing the size of the gadolinium oxysulfide pellets, and the refrigerating efficiency of the refrigerator is improved.

Description

GM refrigerator

Technical Field

The utility model mainly relates to a refrigerator technical field, concretely relates to GM refrigerator.

Background

The GM refrigerator is a device for obtaining ultra-low temperatures based on simon expansion principle, and is widely used in the fields of medical nuclear magnetic resonance and semiconductors. The GM refrigerator drives the piston to reciprocate along the inner wall of the cylinder through the driving device to compress and expand helium, so that the temperature is reduced, and refrigeration is realized.

GM refrigerator need realize from the room temperature to the refrigeration effect of 4K temperature, generally realize the room temperature to the refrigeration effect of 40K through the one-level cold head, then realize the refrigeration effect of 40K to 4K through the second grade cold head, the refrigeration efficiency of second grade cold head mainly with the heat exchange efficiency of inside cold-storage material, heat exchange efficiency is higher, refrigeration efficiency is higher. In order to improve the refrigeration efficiency of the secondary cold head, currently, holmium copper (hoc 2) and gadolinium oxysulfide (Gd 2O 2S) are mostly used as cold storage materials and are filled on the cold end of the secondary cold head in different regions, but the gadolinium oxysulfide has low heat exchange efficiency and needs to be processed into small-sized high-density pellets, but the gadolinium oxysulfide pellets of the structure have small gaps after being filled, so that the liquid helium has large resistance when flowing through the secondary cold head, and the pressure drop of the liquid helium flowing through the gadolinium oxysulfide pellets is large, thereby affecting the heat exchange efficiency and the refrigeration effect of a refrigerator.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome prior art's is not enough, the utility model provides a GM refrigerator, the GM refrigerator adopts porous structure's gadolinium oxysulfide bobble as the cold-storage material, soaks through liquid helium and improves its heat exchange efficiency. Meanwhile, the size of the gadolinium oxysulfide pellets is increased, the pressure drop of the liquid helium after flowing through the gadolinium oxysulfide pellets is reduced, and the refrigerating efficiency of the refrigerator is improved.

The utility model provides a GM refrigerator, which comprises a primary cold head and a secondary cold head connected with one end of the primary cold head, wherein the secondary cold head comprises a secondary cylinder and a secondary piston positioned in the secondary cylinder;

a cold end filling area is arranged in the secondary piston, a first cold accumulation substance is filled in the cold end filling area, and the first cold accumulation substance is gadolinium oxysulfide pellets;

the gadolinium oxysulfide pellet is a porous structure pellet, and liquid helium can be stored in the pores of the porous structure pellet;

the diameter of the gadolinium oxysulfide pellet is d, and the numerical range of d is as follows: d is more than or equal to 0.25mm and less than or equal to 0.8mm.

Further, the density of the gadolinium oxysulfide pellets is between 65% and 95%.

Furthermore, a hot end filling area is further arranged in the secondary piston, and a second cold accumulation substance is filled in the hot end filling area.

Further, the second cold accumulation object is a lead ball, or a zinc alloy, or a bismuth alloy.

Further, a third cold accumulation substance is filled in the cold end filling area and is positioned between the first cold accumulation substance and the second cold accumulation substance.

Further, the third cold accumulation substance is holmium copper.

Further, the working temperature of the hot end filling area is t1, and the interval of t1 is as follows: 10K and t1 are respectively covered with 40K.

Further, the working temperature of the cold end filling area is t2, and the interval of t2 is as follows: the 2K-t 2-straw (10K) is woven.

Further, the GM refrigerator also comprises a driving part, wherein the driving part comprises a driving motor, a crank cam shaft connected to the output end of the driving motor and a crank connecting rod sleeved on the crank cam shaft;

one end of the crank connecting rod is connected with a flange plate, and the crank connecting rod is connected with the primary cold head based on the flange plate.

Further, the primary cold head comprises a primary cylinder, a primary piston positioned in the primary cylinder and a connecting part arranged at one end of the primary piston;

one end of the secondary piston is connected with one end of the primary piston based on the connecting component.

The utility model provides a GM refrigerator, GM refrigerator is filled with porous structure's gadolinium oxysulfide pellet as the cold-storage material in second grade piston intussuseption, soaks through liquid helium and improves the heat exchange efficiency of gadolinium oxysulfide pellet. Meanwhile, the size of the gadolinium oxysulfide pellets of the porous structure is increased, gaps among the filled gadolinium oxysulfide pellets are increased, and resistance of liquid helium flowing through the gadolinium oxysulfide pellets is reduced, so that the pressure drop of the liquid helium flowing through the gadolinium oxysulfide pellets is reduced, and the refrigerating efficiency of the refrigerator is improved.

Drawings

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

FIG. 1 is a schematic diagram of a GM refrigerator in an embodiment of the present invention;

FIG. 2 is a schematic diagram of a secondary piston structure in an embodiment of the present invention;

fig. 3 is a schematic diagram of specific heat capacity by volume of gadolinium oxysulfide and holmium copper at different temperatures.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

The first embodiment is as follows:

fig. 1 shows GM refrigerator structure schematic in the embodiment of the present invention, GM refrigerator includes drive arrangement 1, connects the one-level cold head 2 and the connection of drive arrangement 1's drive end are in one-level cold head 2 one serves one second grade cold head 3, drive arrangement 1 includes driving motor 11, has the crank connecting rod 13 of cooperation groove 131 and cup joints crank camshaft 12 in the cooperation groove 131, crank camshaft 12 is being based on the coupling joint driving motor 11's output shaft, driving motor 11 drive crank camshaft 12 rotates, crank camshaft 12 is based on cooperation groove 131 drives crank connecting rod 13 reciprocating motion.

Further, a motor driving sleeve 14 is sleeved outside the crank-cam shaft 12, and the motor driving sleeve 14 is used for reducing friction between the crank-cam shaft 12 and the matching groove 131, so that the service life of the device is ensured.

Specifically, one-level cold head 2 includes one-level cylinder 21, one-level piston 22 and top end cover 23, one-level piston 22 cup joints in the one-level cylinder 21, top end cover 23 is fixed one of one-level cylinder 21 is served, be provided with guide way 231 and connect through groove 232 in the top end cover 23, guide way 231 is based on connect through groove 232 with one-level cylinder 21 intercommunication, the one end setting of crank connecting rod 13 is in the guide way 231.

Specifically, one-level cold head 2 still includes ring flange 24, ring flange 24 is used for connecting one-level piston 22 with crank connecting rod 13, one end of one-level piston 22 is fixed ring flange 24, crank connecting rod's the other end passes through connect groove 232 to extend inside one-level cylinder 21, and connect and be in on the ring flange 24. When the driving motor 11 drives the crank connecting rod 13 to move, the crank connecting rod 13 reciprocates in the guide groove 231, and the guide groove 231 can limit the movement of the crank connecting rod 13 to play a guiding role. The primary piston 22 reciprocates in the primary cylinder 21 with the crank link 13.

Furthermore, a piston dynamic sealing ring is arranged at the connecting position of the primary piston 22 and the crank connecting rod 13, and the piston dynamic sealing ring ensures the sealing performance of the primary piston 22 and ensures the refrigerating effect of the refrigerator.

Specifically, the second-stage cold head 3 includes a second-stage cylinder 31 and a second-stage piston 32, the second-stage piston 32 is sleeved in the second-stage cylinder 31, the first-stage cylinder 21 and the second-stage cylinder 31 are communicated with each other, one end of the second-stage piston 32 is provided with a connecting component 33, the second-stage piston 32 is based on the connecting component 33 and the first-stage piston 22, and the second-stage piston 32 is under the action of the first-stage piston 22 and moves back and forth inside the second-stage cylinder 31.

Fig. 2 shows a schematic diagram of a secondary piston structure in an embodiment of the present invention, the inside of the secondary piston 32 is provided with a holding cavity 321, the holding cavity 321 is used for storing cold storage material, the cold storage material includes a first cold storage 3221, a second cold storage 3231 and a third cold storage 3222, the holding cavity 321 is provided with a hot end filling area 323 and a cold end filling area 322, the hot end filling area 323 is located near the region of the primary piston 22, the working temperature of the hot end filling area 323 is t1, the interval of t1 is: 10K-t 1-40K, wherein K represents Kelvin temperature. The second cold storage material 3231 is filled in the hot end filling region 323.

Further, the cold end packing area 322 is located in a region away from the primary piston 22, the operating temperature of the cold end packing area 322 is t2, and the interval of t2 is: the 2K-t 2-straw (10K), the first cold accumulation 3221 and the third cold accumulation 3222 are filled in the cold end filling region 322.

Further, the third cold accumulation 3222 is located between the first cold accumulation 3221 and the second cold accumulation 3231, and during the operation of the GM refrigerator, helium gas in the GM refrigerator passes through the second cold accumulation 3231, the third cold accumulation 3222 and the first cold accumulation 3221 in sequence, so that a refrigeration effect of a temperature of 40K to 4K is realized.

Further, the second cold accumulation material 3231 may be a shot, a zinc alloy, or a bismuth alloy.

Specifically, the first cold storage material 3221 is a gadolinium oxysulfide pellet, the gadolinium oxysulfide pellet is a porous structure pellet, liquid helium can be carried in a porous structure of the porous structure pellet, and the gadolinium oxysulfide pellet can be infiltrated by liquid helium, so that the heat exchange efficiency between the first cold storage material 3221 and the liquid helium is improved.

Further, the liquid helium soaked in the porous structure can also be used as a cold storage material, so that the refrigeration effect of the secondary piston 32 is improved.

Specifically, the diameter of the gadolinium oxysulfide pellet is d, and the value range of d is as follows: d is more than or equal to 0.25mm and less than or equal to 0.8mm, and the density of the gadolinium oxysulfide balls is between 65 and 95 percent. The first cold accumulation material 3221 may adopt gadolinium oxysulfide pellets with a specific density and a large spherical diameter, so as to reduce the pressure drop when the liquid helium flows through the filling region, and improve the refrigeration efficiency.

It is noted that the pressure drop refers to the pressure difference of the liquid helium before and after passing through the first cold accumulation object 3221, the magnitude of the pressure drop reflects the energy loss of the liquid helium, and the magnitude of the pressure drop is mainly related to the resistance received by the fluid, and the smaller the resistance received, the smaller the pressure drop, the smaller the energy loss of the fluid. The energy loss mainly comes from the fact that when liquid helium passes through the first cold accumulation material 3221, resistance between the liquid helium and the first cold accumulation material 3221 is overcome, and the size of gadolinium oxysulfide pellets is increased, gaps among the filled gadolinium oxysulfide pellets are increased, so that the resistance of the liquid helium flowing through the first cold accumulation material 3221 is reduced, and energy loss caused by friction is reduced.

Specifically, fig. 3 shows a schematic diagram of specific heat capacity of gadolinium oxysulfide and holmium copper at different temperatures, where the third cold storage object 3222 is holmium copper, and in an interval where the temperature is less than 6K, the specific heat capacity of gadolinium oxysulfide in a low-temperature environment is greater than the specific heat capacity of holmium copper, and in an interval where the temperature is 6K to 10K, the specific heat capacity of gadolinium oxysulfide in a low-temperature environment is less than the specific heat capacity of holmium copper, and the refrigeration efficiency of the cold-end filling area 322 can be effectively improved by filling holmium copper and gadolinium oxysulfide in the cold-end filling area 322 in different regions according to temperature changes.

The utility model provides a GM refrigerator, GM refrigerator is filled with porous structure's gadolinium oxysulfide bobble as the cold-storage material in the second grade piston intussuseption, soaks through liquid helium and improves the heat exchange efficiency of gadolinium oxysulfide bobble. By increasing the size of the gadolinium oxysulfide pellets with a porous structure, gaps among the gadolinium oxysulfide pellets after filling are increased, and resistance of the liquid helium when the liquid helium flows through the gadolinium oxysulfide pellets is reduced, so that the pressure drop of the liquid helium when the liquid helium flows through the gadolinium oxysulfide pellets is reduced, and the refrigerating efficiency of the refrigerator is improved.

Example two:

in this embodiment, two prototype machines with the same overall dimensions are selected, the refrigeration effects of the gadolinium oxysulfide pellet with the porous structure and the gadolinium oxysulfide pellet with the traditional high-density structure are compared and tested, and the test data are collated to obtain table 1:

TABLE 1 comparative test refrigeration Effect

Wherein, prototype 1 is filled with gadolinium oxysulfide pellets with a porous structure, and prototype 2 is filled with gadolinium oxysulfide pellets with a traditional high-density structure.

Specifically, as can be seen from the above table, under the condition of 1.25W power and the same filling quality, the refrigerating temperature of prototype 1 is 3.67K, and the refrigerating temperature of prototype 2 is 3.9K, and the lower the temperature, the higher the refrigerating capacity of the refrigerator is, and the better the refrigerating effect of the refrigerator is. By comparison, the refrigeration temperature of the gadolinium oxysulfide pellet with the porous structure is reduced by about 0.23K compared with that of the gadolinium oxysulfide pellet with the traditional high-density structure under the same condition, and the refrigeration efficiency of the refrigerator is effectively improved.

In addition, the GM refrigerator provided by the embodiment of the present invention is described in detail above, and the principle and the implementation of the present invention are explained by using a specific example herein, and the description of the above embodiment is only used to help understand the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be changes in the specific embodiments and the application range, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims

1. The GM refrigerator is characterized by comprising a primary cold head and a secondary cold head connected to one end of the primary cold head, wherein the secondary cold head comprises a secondary cylinder and a secondary piston positioned in the secondary cylinder;

the gadolinium oxysulfide pellet is a porous structure pellet, and liquid helium is stored in the pores of the porous structure pellet;

the diameter of the gadolinium oxysulfide pellet is d, and the value range of d is as follows: d is more than or equal to 0.25mm and less than or equal to 0.8mm.

2. The GM refrigerator of claim 1, wherein the gadolinium oxysulfide pellets have a density between 65% and 95%.

3. The GM refrigerator of claim 1, wherein a hot side fill region is further disposed within the secondary piston, the hot side fill region filled with a second cold storage substance.

4. The GM refrigerator of claim 3, wherein the second cold accumulator is a shot, or a zinc alloy, or a bismuth alloy.

5. The GM refrigerator of claim 3, wherein the cold end packing region is further filled with a third cold store located between the first cold store and the second cold store.

6. The GM refrigerator of claim 5 where the third cold storage material is holmium copper.

7. The GM refrigerator of claim 3, wherein the hot end fill region operating temperature is t1, the interval of t1 being: 10K-t 1-40K were designed.

8. The GM refrigerator of claim 1, wherein the cold end packing region has an operating temperature t2, the interval of t2 being: the 2K-t 2-straw (10K) is woven.

9. The GM refrigerator of claim 1 further including a drive component including a drive motor, a crank-cam shaft connected to an output of the drive motor, and a crank link sleeved on the crank-cam shaft;

10. The GM refrigerator of claim 1, wherein the primary coldhead comprises a primary cylinder, a primary piston located inside the primary cylinder, and a connecting member disposed on one end of the primary piston;