CN1764811A - Pulse tube refrigerating machine - Google Patents

Abstract

The present invention provides a pulse tube refrigerating machine advantageous for increasing refrigeration capacity. The pulse tube refrigerating machine comprises a pressure waveform generating device (1) for producing a pressure waveform for a refrigerant gas, pulse tubes (14, 20) into which a refrigerant gas having the pressure waveform flows and whose one end is a lower temperature end and whose other end is a higher temperature end, cold storage units (8, 10) for pre-cooling the refrigerant gas flowing into the pulse tubes (14, 20), a pressure waveform phase control element which has a buffer tank (23) communicating with the higher temperature end of the pulse tube (20) and which controls the phase of the pressure waveform of the refrigerant gas for the purpose of refrigeration at the lower temperature end of the pulse tube (20), and a vacuum heat-insulation tank (24) having a vacuum heat-insulation chamber (24w) for receiving the pulse tube (20). The buffer tank (23) is disposed in the vacuum heat-insulation chamber (24w) of the vacuum heat-insulation tank (24).

Description

Pulse Tube Refrigerator

technical field

The invention relates to a pulse tube refrigerator for producing ultra-low temperature.

Background technique

As a prior art, there is a pulse tube refrigerator as shown in FIG. 8 (patent document: Japanese Patent Application Laid-Open No. 9-296963). The structure of the pulse tube refrigerator is shown in Figure 8, including: compressor 121; low pressure supply valves 122, 124, 126; high pressure supply valves 123, 125, 127; first pulse tube 107; second pulse tube 117; 1 regenerator 103 and the 2nd regenerator 13. The first pulse tube 107 has a high temperature end 107H and a low temperature end 107L. The second pulse tube 117 on the lower temperature side has a high temperature end 117H and a low temperature end 117L.

According to this structure of the pulse tube refrigerator, the high temperature end 117H of the second pulse tube 117 is installed in the room temperature portion and cooled by air. Therefore, due to the large volume of the second pulse tube 117, it is limited to increase the compression ratio of the refrigerant gas in the refrigeration circuit. There are limits.

And, according to this pulse tube refrigerating machine structure, because the warm gas that is equal to or greater than room temperature flows into the low temperature end of the 2nd pulse tube 117 from the high temperature end 117H of the 2nd pulse tube 117, therefore, in this sense, improve the 2nd pulse The refrigeration capacity produced by the low-temperature end 117L of the tube 117 is also limited.

Meanwhile, as a prior art, there is a pulse tube refrigerator disclosed in a document as shown in FIG. 9 (Non-Patent Document 1: Cryocoolers11, P189-198 Design and Test of the NIST/Lockheed Martin MinituaturePulse TubeFlight Cryoosooler). As shown in FIG. 9 , the pulse tube refrigerator includes: a compressor 209 , a first pulse tube 201 , a second pulse tube 203 , a first regenerator 207 , a second regenerator 206 and orifices 300 , 301 , 302 . The first pulse tube 201 has a high temperature end 201H and a low temperature end 201L. The second pulse tube 203 on the lower temperature side has a high temperature end 203H and a low temperature end 203L.

According to the structure of the pulse tube refrigerator, the high temperature end 203H of the second pulse tube 203 is connected to the low temperature end 201L of the first pulse tube 20. Therefore, the high temperature end 203H of the second pulse tube 203 passes through the first pulse tube 201 The generated refrigeration is cooled, and the high temperature end 203H of the second pulse tube 203 is only set on the low temperature end 201L of the first pulse tube 201, even if the gas compression ratio of the refrigerant gas is larger, the low temperature end 203L of the second pulse tube 203 must be Less than a good cooling effect.

(Patent Document 1: Japanese Patent Application Laid-Open No. 9-296963)

(Non-Patent Document 1: Cryocoolers 11, P189-198 Design and Test of the NIST/Lockheed Martin Minituature Pulse Tube Flight Cryoosooler)

Contents of the invention

The present invention is implemented in view of the above-mentioned actual situation, and the purpose is to provide a pulse tube refrigerator which is beneficial to improve the refrigeration capacity.

The pulse tube refrigerator of the first form in the present invention comprises: a pressure waveform generating device, which causes the refrigerant gas to generate a pressure waveform; is the low temperature end, and the other end is the high temperature end; the regenerator is arranged between the pressure waveform generating device and the above-mentioned pulse tube, and precools the refrigerant gas flowing into the pulse tube; the pressure waveform phase controller has a The high temperature end is connected to the buffer box, and the phase of the pressure waveform of the refrigerant gas is controlled, so as to produce a cooling effect at the low temperature end of the pulse tube: a vacuum insulation tank, which has a vacuum insulation chamber for the pulse tube, and the pulse tube The feature of the refrigerator is that the buffer box is arranged in the vacuum heat insulation chamber of the vacuum heat insulation tank.

According to the pulse tube refrigerator of the first form in the present invention, both the buffer tank and the pulse tube are arranged in the vacuum heat insulation chamber of the vacuum heat insulation tank. Thus, air heat entry into the buffer tank is controlled. In this way, the refrigerant gas in the buffer tank can be kept at a low temperature. Therefore, the compression ratio of the refrigerating gas in the refrigerating circuit can be increased: increasing the amount of refrigeration generated at the low-temperature end of the pulse tube is beneficial to improving the refrigerating capacity of the pulse tube refrigerator.

According to the pulse tube refrigerator of the first aspect of the present invention, when the first buffer tank and the second buffer tank are provided, the second buffer tank on the low temperature side can be installed in the vacuum heat insulation tank.

According to various forms of the present invention, the pressure waveform generator is used to generate the pressure waveform of the refrigerant gas. For example, a compressor is used to generate a pressure waveform. The cold accumulator is arranged between the pressure waveform generating device and the pulse tube, and has the function of cooling the refrigerant gas flowing to the pulse tube. The cold accumulator can be made of materials with large heat capacity such as metal.

According to the various forms shown in the description of the present invention, the inside of the vacuum heat insulation chamber of the vacuum heat insulation tank is kept in a high vacuum state, thereby achieving vacuum heat insulation. The vacuum state under this condition can reach below 10 ^-3 Torr (below 133×1.0 ^-3 pa), more ideally it can reach below 10 ^-4 Torr (below 133×10 ^-4 pa).

(2) The pulse tube refrigerator of the second form in the present invention includes: a pressure waveform generating device, which causes the refrigerant gas to generate a pressure waveform; , and one end is a low-temperature end, and the other end is a high-temperature end: a regenerator, which is arranged between the pressure waveform generator and the pulse tube, and precools the refrigerant gas flowing into the pulse tube; a pressure waveform phase controller, which has The inertial tube connected to the high temperature end of the pulse tube and the inner diameter of the flow path is smaller than the inner diameter of the pulse tube, and the buffer tank connected to the high temperature end of the pulse tube through the inertial tube, and the phase of the pressure waveform of the refrigerant gas is controlled, so that the low temperature of the pulse tube The cooling effect is generated at the end; the vacuum heat insulation tank has a vacuum heat insulation chamber for accommodating the above-mentioned pulse tube refrigerator.

According to the pulse tube refrigerator of the second form in the present invention, the refrigerant gas at the high temperature end of the pulse tube flows into and out of the buffer tank through the inertial tube whose inner diameter of the flow path is smaller than the inner diameter of the pulse tube. At this time, the phase of the pressure waveform of the refrigerant gas is adjusted to keep the cooling capacity of the low temperature end of the pulse tube in good condition. The inertia tube and the buffer box have the function of a pressure waveform phase control device for adjusting the refrigerant gas phase and pressure increase. From the point of view of having the function of adjusting the phase of the refrigerant gas pressure waveform, when considering the correspondence with the circuit, the inertial tube will act as an inductor in the circuit (the function of generating the phase difference of the refrigerant gas).

According to the pulse tube refrigerator of the second aspect of the present invention, both the inertial tube and the pulse tube are arranged in the vacuum heat insulation chamber of the vacuum heat insulation tank. Therefore, air heat entering the inertial tubes can be controlled. Therefore, the refrigerant gas flowing in the inertia tube is kept at a low temperature. Therefore, the compression ratio of the refrigerating gas in the refrigerating circuit can be increased, which is beneficial to increasing the amount of refrigeration generated at the low-temperature end of the pulse tube and improving the refrigerating capacity of the pulse tube refrigerator.

Especially if the refrigerant gas flowing in the inertia tube is low temperature, then the flow path resistance of the inertia tube is small, and the viscous loss of the gas flowing in the inertia tube is small. As a result, the phase and quantity of refrigerant gas flowing to the high temperature end of the pulse tube are kept good, thereby increasing the refrigeration capacity.

According to the pulse tube refrigerator of the second form in the invention, when the first inertia tube communicated with the first buffer tank and the first inertia tube communicated with the second buffer tank are provided, the second inertia tube at the low temperature end can be The tubes are arranged in a vacuum insulation tank.

(3) The pulse tube refrigerator of the third form in the present invention includes: a pressure waveform generating device that generates a pressure waveform for the refrigerant gas; Gas, and one end is a low-temperature end, and the other end is a high-temperature end; the second pulse tube flows into a refrigerant gas with a pressure waveform, and one end is a low-temperature end whose temperature is lower than the low-temperature end of the first pulse tube, and the other end is a high-temperature end : cold accumulator, which is arranged between the pressure waveform generating device and the first pulse tube and the second pulse tube, precooling the refrigerant gas flowing into the first pulse tube and I or the second pulse tube: pressure waveform phase controller, It has: the first inertia tube connected to the high temperature end of the first pulse tube, and the inner diameter of the flow path is smaller than the inner diameter of the first pulse tube; the first buffer tank connected to the high temperature end of the first pulse tube through the first inertia tube; and The high-temperature end of the second pulse tube is connected, and the inner diameter of the flow path is smaller than the second inertia tube of the second pulse tube; the second buffer tank is connected to the high-temperature end of the second pulse tube through the second inertia tube; and, for refrigeration The phase of the pressure waveform of the gas is controlled to produce a cooling effect; the vacuum heat insulation tank has a vacuum heat insulation chamber for at least accommodating the second pulse tube. The cooling device is in thermal contact and is cooled by the freezing effect from the low temperature end of the first pulse tube, and the cooling device is in thermal contact with the second inertial tube.

According to the structure of the pulse tube refrigerator shown in the third aspect of the present invention, the refrigerant gas at the high temperature end of the pulse tube flows into and out of the buffer tank through the inertial tube whose inner diameter of the flow channel is smaller than the inner diameter of the pulse tube. At this time, the phase of the pressure waveform of the refrigerant gas is adjusted to keep the refrigeration capacity at the low temperature end of the pulse tube in good condition. The inertia tube and the buffer box have the function of being a pressure waveform phase control device for adjusting the refrigerant gas phase and pressure increase. From the point of view of the function of adjusting the phase of the pressure waveform of the refrigerant gas, if the correspondence with the circuit is considered, the inertial tube will act as an inductor in the circuit.

Furthermore, a cooling device is provided which is in thermal contact with the low-temperature end of the first pulse tube and is cooled by freezing action from the low-temperature end of the first pulse tube. Therefore, the cooling device is cooled by the freezing action at the low temperature end of the first pulse tube.

Moreover, according to the pulse tube refrigerator of the third form in the present invention, since the cooling device is in thermal contact with the second inertial tube, the second inertial tube is cooled by refrigeration from the low temperature end of the first pulse tube. Therefore, the refrigerant gas flowing in the inertial tube can be kept at a low temperature, so the compression ratio of the refrigerant gas in the refrigeration circuit can be increased, and the amount of refrigeration generated at the low-temperature end of the pulse tube can be increased, which is conducive to improving the refrigeration performance of the pulse tube refrigerator. ability.

Especially when the refrigerant gas flowing in the inertial tube is at a low temperature, the flow channel resistance of the inertial tube becomes smaller, and the viscosity loss of the gas flowing in the inertial tube is reduced. As a result, the phase and amount of the refrigerant gas flowing at the high temperature end of the pulse tube can Stays in good condition, thus increasing cooling capacity.

The cooling device is preferably made of metal with good heat transfer performance. For example, the cooling device can be formed from a metal plate. The shape of the metal plate is not particularly specified. In order to improve the cooling performance of the inertial tube, the thermal contact area between the cooling device and the inertial tube can be increased.

(4) The pulse tube refrigerator of the fourth form in the present invention includes: a pressure waveform generating device, which causes the refrigerant gas to generate a pressure waveform; Refrigerant gas, and one end is a low-temperature end, and the other end is a high-temperature end; the second pulse tube flows into a refrigerant gas with a pressure waveform, and one end is a low-temperature end whose temperature is lower than the low-temperature end of the first pulse tube, and the other end is a high-temperature end ; The cold accumulator, which is arranged between the pressure waveform generating device and the second pulse tube and the second pulse tube, precools the refrigerant gas flowing into the first pulse tube and/or the second pulse tube; the pressure waveform phase controller, Including: the first inertia tube connected to the high temperature end of the first pulse tube, and the inner diameter of the flow path is smaller than the inner diameter of the first pulse tube; the first buffer tank connected to the high temperature end of the first pulse tube through the first inertia tube; The high-temperature ends of the two pulse tubes are connected, and the inner diameter of the flow path is smaller than the second inertia tube; the second buffer tank is connected to the high-temperature end of the second pulse tube through the second inertia tube, and the cooling gas The phase of the pressure waveform is controlled to produce a cooling effect; the vacuum heat insulation tank is equipped with a vacuum heat insulation chamber for at least accommodating the second pulse tube. Contact, and use the cooling device for cooling by the freezing effect from the low-temperature end of the first pulse tube, and make the cooling device thermally contact with the second buffer tank.

According to the fourth aspect of the pulse tube refrigerator of the present invention, a cooling device is provided which is in thermal contact with the low temperature end of the first pulse tube and cooled by refrigeration from the low temperature end of the first pulse tube. Therefore, the cooling device is cooled by the freezing effect of the low-temperature end of the first pulse tube.

Furthermore, according to the pulse tube refrigerator of the fourth aspect of the present invention, the second buffer tank is cooled by the refrigeration effect from the low-temperature end of the first pulse tube by thermally contacting the cooling device with the second buffer tank. Therefore, the refrigerant gas in the second buffer tank can be kept at a low temperature. Therefore, the compression ratio of the refrigerant gas in the refrigeration circuit can be increased, and the amount of refrigeration generated at the low-temperature end of the pulse tube can be increased, thereby improving the refrigeration capacity of the pulse tube refrigerator.

The cooling device relies on thermal contact with the low-temperature end of the first pulse tube, and utilizes the freezing effect from the low-temperature end of the first pulse tube for cooling. As a cooling device, it is best to use metals with good heat transfer performance (generally aluminum alloys, copper alloys and iron alloys) to make. The shape of the cooling device is not particularly limited, and for example, a metal plate can be used. The shape of the metal plate is also not particularly specified. In order to improve the cooling performance for the second buffer tank as much as possible, the thermal contact area between the cooling device and the second buffer tank can be made larger.

(5) The pulse tube refrigerator of the fifth form in the present invention includes: a pressure waveform generating device, which causes the refrigerant gas to generate a pressure waveform; Gas, and one end is a low-temperature end, and the other end is a high-temperature end; the second pulse tube flows into a refrigerant gas with a pressure waveform, and one end is a low-temperature end whose temperature is lower than that of the first pulse tube low-temperature end, and the other end is a high-temperature end; The cold accumulator, which is arranged between the pressure waveform generator and the first pulse tube and the second pulse tube, precools the refrigerant gas flowing into the first pulse tube and/or the second pulse tube; the pressure phase controller, Including: the first inertia tube connected to the high temperature end of the first pulse tube, and the inner diameter of the flow path is smaller than the inner diameter of the first pulse tube; the first buffer tank connected to the high temperature end of the first pulse tube through the first inertia tube; The high temperature ends of the two pulse tubes are connected, and the inner diameter of the flow path is smaller than the second inertia tube; the second buffer tank is connected to the high temperature end of the second pulse tube through the second inertia tube, and the cooling gas The phase of the pressure waveform is controlled to produce a cooling effect: a vacuum heat insulation tank, which has a vacuum heat insulation chamber for at least accommodating the second pulse tube. The low temperature end of the pulse tube is in thermal contact.

According to the fifth aspect of the pulse tube refrigerator of the present invention, the second inertial tube is in thermal contact with the low temperature end of the first pulse tube. At this time, at least a part of the second inertial tube is cooled due to the freezing effect from the low-temperature end of the first pulse tube. In this way, the refrigerant gas flowing in the second inertia tube can be kept at a low temperature. Therefore, the compression ratio of the refrigerating gas in the refrigerating circuit can be improved, and the amount of refrigeration generated at the low-temperature end of the second pulse tube is increased, which is beneficial to improving the refrigerating capacity of the pulse tube refrigerator.

In particular, the inner diameter of the flow path of the second inertia tube is relatively small. Compared with the case where the inner diameter of the flow path of the second inertia tube is large, except for the refrigerant gas flowing on the outer wall side of the second inertia tube, it flows in the center of the second inertia tube. The refrigerant gas can also be effectively cooled, so the entire refrigerant gas flowing in the second inertia tube can be effectively cooled.

According to the pulse tube refrigerator of the fifth form in the invention, for example, the second inertia tube can be wound into a spiral shape at the low temperature end of the first pulse tube so as to be in thermal contact with the low temperature end of the first pulse tube .

(effect of invention)

The present invention can provide a pulse tube refrigerator which is beneficial to improve the refrigeration capacity of the low temperature end of the pulse tube.

Description of drawings

FIG. 1 is a configuration diagram showing the concept of a pulse tube refrigerator in a first embodiment.

Fig. 2 is a configuration diagram showing a contact portion between a second inertial tube and a shield plate in the first embodiment.

Fig. 3 is a configuration diagram showing the concept of a pulse tube refrigerator in a second embodiment.

Fig. 4 is a configuration diagram showing a state of contact between a second buffer box and a shield plate in a third embodiment.

Fig. 5 is a configuration diagram showing the surroundings of a second buffer tank in a fourth embodiment.

Fig. 6 is a configuration diagram showing the surroundings of a second buffer tank in the fifth embodiment.

Fig. 7 is a configuration diagram showing a state in which the second inertia tube is wound at the low temperature end of the first buffer tank in the sixth embodiment.

Fig. 8 is a block diagram showing the concept of a conventional pulse tube refrigerator.

Fig. 9 is a block diagram showing the concept of a conventional pulse tube refrigerator.

Detailed ways

Embodiments of the present invention will be described below with reference to the drawings.

(first embodiment)

The first embodiment is as shown in the figure. In FIG. 1 , 1 is a linear drive compressor, which can be used as a pressure waveform generating device, which can generate a pressure waveform for gaseous refrigerant gas. In the compressor 1 , a space between the reciprocating piston 2 and the piston 3 constitutes a compression section 4 . Compression unit 4 communicates with one end 6 a of radiator 6 through pipe 5 , and the other end 6 b of radiator 6 is connected with first regenerator 8 filled with regenerator material 7 such as wire mesh. A cylindrical connection member 9 in contact with the second regenerator 10 is provided on the low-temperature end 8b of the first regenerator 8 . The inside of the second regenerator 10 is filled with lead or rare earth spherical regenerator material 12 having a regenerator function. The second regenerator 10 is maintained at a temperature lower than that of the first regenerator 8 . Inside the connection member 9, a flow path member 11 is arranged. The flow path member 11 communicates with the first pulse tube 14 and the second pulse tube 20 , and the refrigerant gas toward the first pulse tube 14 and the refrigerant gas toward the second pulse tube 20 flow therein.

As shown in FIG. 1 , one end 13 a of a pipe 13 through which the refrigerant flows is provided on the outer wall that is the peripheral surface of the connection member 9 . The other end 13b of the pipe 13 communicates with the first heat exchanger 15 . The first heat exchanger 15 is provided at the low temperature end 14L of the first pulse tube 14 .

The first pulse tube 14 is a vertically long metal tubular member with a hollow chamber inside which the refrigerant gas can flow. The inflowing refrigerant gas has a pressure waveform generated at the compression part 4 . Here, the upper end (the other end) of the first pulse tube 14 is the high temperature end 14H, and the lower end (one end) of the first pulse tube 14 is the low temperature end 14L. The purpose of installing the low-temperature end 14L below is to control the heat convection of the refrigerant gas.

As shown in FIG. 1 , the high temperature end 14H of the first pulse tube 14 is connected to one end of the first radiator 16 . The first heat sink 16 is disposed on the outer side of the vacuum insulation tank 24 . The other end of the first radiator 16 is connected to one end 17a of a metal first inertia tube 17 having an elongated shape as a first communication tube. The first inertial tube 17 functions as a reactor in the circuit. The inner diameter of the first inertia tube 17 is relatively smaller than the inner diameter of the first pulse tube 14 and the inner diameter of the first buffer tank 18 . The other end 17 b of the first inertia tube 17 is connected to the first buffer tube 18 . The first buffer tank 18 is provided with a large-capacity storage room 18W.

Here, the refrigerant gas from the first pulse tube 14 travels to and from the inside of the first buffer tank 18 through the first inertial tube 17 to adjust the pressure waveform phase and pressure amplitude of the refrigerant gas. Therefore, the first inertial tube 17 and the first buffer tank 18 are used as pressure waveform phase control devices to control the phase and pressure waveform amplitude of the refrigerant gas pressure waveform in order to produce a freezing effect at the low temperature end 14L of the first pulse tube 14 . The first inertia tube 17 and the first buffer tank 18 are arranged outside the vacuum insulation tank 1 as shown in FIG. 1 .

As shown in FIG. 1 , the low-temperature end 10L of the second regenerator 10 communicates with a second heat exchanger 30 having a function of cooling refrigerant gas by heat exchange through a pipe 19 . The second heat exchanger 30 is provided at the low temperature end 20L of the second pulse tube 20 (the temperature is relatively lower than that of the low temperature end 14L of the first pulse tube 14 ). The second pulse tube 20 is a long metal tubular part with a vertically long hollow chamber inside, allowing refrigerant gas to flow in. Here, the length of the second pulse tube 20 is set relatively shorter than the length of the first pulse tube 14 . At the same time, the inner diameter of the second pulse tube 20 is set relatively smaller than the inner diameter of the first pulse tube 14 . Therefore, the volume of the second pulse tube 20 is set to be smaller than the volume of the first pulse tube 14 . The upper end of the second pulse tube 20 is at a high temperature 20H, and the lower end of the second pulse tube 20 is at a low temperature 20L. The purpose of the lower temperature end 20L is to control heat convection.

The high temperature end 20H of the second pulse tube 20 is provided with a second radiator 21 having various cooling functions. The second heat sink 21 is in thermal contact with the cylindrical portion 9a of the contact member 9 from the outside through the heat-conducting flange 9b. As described above, the inner surface of the cylindrical portion 9 a of the contact member 9 is provided with a flow path through which the refrigerant gas cooled at the low-temperature end 14L of the first pulse tube 14 flows. Therefore, the second radiator 21 is cooled by the refrigerant gas flowing through the cylindrical portion 9 a of the contact member 9 .

In other words, the high temperature end 20H of the second pulse tube 20 is in thermal contact with the second radiator 21 and is cooled by the second radiator 21 . As a result, the high temperature end 20H of the second pulse tube 20 is cooled by the freezing effect generated at the low temperature end 14L of the first pulse tube 14 . The high-temperature end 20H of the second radiator 21 and the second pulse tube 20 keeps a lower temperature, even under the same flow rate, it is beneficial to reduce the volume of the refrigerant gas in the second pulse tube 20, and shorten the second pulse tube 20. The length of pulse tube 20. Therefore, it is beneficial to improve the compression ratio of the refrigeration circuit, and the amount of refrigeration generated at the low-temperature end 20L of the second pulse tube 20 is greatly increased compared with the prior art.

According to this embodiment, as shown in FIG. 1 , a shield plate 25 is provided to play a role of cooling the device. The shielding plate 25 is a metal product with good thermal conductivity. As shown in FIG. at low temperature.

A box-shaped shield 26 is in thermal contact with the shield plate 25 as a cooling device. The shield case 26 is disposed under the shield plate 25 and forms a shield chamber 26W. Since the shield case 26 communicates with the vacuum heat insulation chamber 24W, it is in a high vacuum state like the vacuum heat insulation chamber 24W.

As shown in FIG. 2 , the metallic second inertial tube 22 , which is composed of an elongated pipe, is in thermal contact with the shield plate 25 . The second inertial tube 22 plays the role of connecting the second buffer tank 23 with the second pulse tube 20 as the second connecting tube, and has the function of controlling the gas flow rate, and its inner diameter is relatively smaller than the inner diameter of the second pulse tube 20 and the second pulse tube 20. 2. The inner diameter of the buffer box 23.

In addition, as shown in FIG. 1 , an upper portion 23 u of the second buffer tank 23 is in thermal contact with the shield plate 5 . The second buffer box 23 is arranged below the shield plate 25 . The second buffer tank 23 has a tank chamber 23W with a larger volume, and the volume of the tank chamber 23 is relatively smaller than that of the tank chamber 18W of the first buffer tank 18 . As described above, the shield plate 25 serving as a cooling device is also in thermal contact with the second buffer tank 23 . In this way, the second buffer tank 23 is cooled by the shielding plate 25, and the refrigerant gas in the second buffer tank 23 is kept at a low temperature.

Here, the refrigerant gas from the second pulse tube 20 passes through the second inertia tube 22 and flows back and forth inside the second buffer tank 23 , so that the pressure waveform phase and pressure amplitude of the refrigerant gas supplied to the second pulse tube 20 are adjusted. Therefore, the second inertial tube 22 and the second buffer tank 23 produce a freezing effect at the low temperature end 20L of the second pulse tube 20, so they function as a pressure waveform phase control device for controlling the phase of the refrigerant gas pressure waveform.

According to the present embodiment, as shown in FIG. 1 , the second buffer tank 23 is not disposed in the air, but is disposed in the vacuum insulation chamber 24W of the vacuum insulation tank 24 . In particular, the second buffer tank is installed in the shield room 26W of the shield case 2 in the vacuum insulation tank 24 . The shielding cover 2 is used as an anti-radiation heat conduction device to control the conduction of heat radiation from the outside.

Therefore, in order to keep the refrigerant gas in the second buffer tank 23 at a lower temperature, the inside of the vacuum insulation chamber 24W of the vacuum insulation tank 24 is connected to the vacuum pump 24X, and kept in a high vacuum state (below 10 ^-4 Torr133X10 ^-4 Pa or less). The vacuum heat insulation tank 24 has good heat insulation performance.

The wall body of the vacuum heat insulation tank 24 is made of a material with high heat insulation performance that suppresses heat conduction. The shielding cover 26 is arranged inside the vacuum insulation tank 24 to control the heat radiation from the outside, and is made of metal with excellent thermal conductivity as the base material.

According to this embodiment, as shown in FIG. 1 , in the shielding room 26W of the shielding case 26, in addition to the second buffer tank 23, the second regenerator 10, the second pulse tube 20 and the second radiator 21 are accommodated. to prevent thermal contact of these devices with air. The first pulse tube 14 is located outside the shield case 26 as shown in FIG. 1 and accommodated in the vacuum insulation tank 24 .

When in use, the pistons 4 and 5 of the compressor 1 are set relative to each other and perform reciprocating motion at a certain frequency. In this way, the refrigerant gas in the compression part 4 of the compressor 1 is compressed by the pistons 4 and 5 at the same frequency, and a pressure waveform of the refrigerant gas (generally nitrogen (He)) is generated. When setting the size of each part, it is necessary to ensure that the resonance frequency of the gas pressure in the first buffer box 18 and the first inertia tube 17, and the resonance frequency of the gas pressure in the second buffer 23 and the second inertia tube 25, and The operating frequencies of the pistons 5 and 6 are basically consistent. In this way, the low temperature end 14L of the first pulse tube 14 and the low temperature end 20L of the second pulse tube 20 obtain a pressure waveform similar to the Stirling cycle. Near ideal freezing capacity can be obtained at the low temperature end of 20L.

In addition, according to different operating conditions, the freezing effect at the low temperature end 14L of the first pulse tube 14 can be obtained at a temperature of 40-100K, and the cooling effect at a temperature of 10-30K can be obtained at the low temperature end 20L of the second pulse tube 20 . Its empty thermal insulation groove 24 and shielding case 26 have the effect of stopping the conduction heat from vacuum thermal insulation groove 24. The temperature of the shielding room 26W of the shielding case 26 can generally reach about 40-100K. The shield cover 26 has a function of preventing radiant heat from the vacuum insulation tank 24 .

According to this embodiment, the refrigerant gas obtained at a low temperature by the cooling generated at the low-temperature end 14L of the first pulse tube 14 flows inside the cylindrical portion 9a of the contact member 9 . As a result, the contact member 9 is cooled, and the temperature of the second heat sink 21 that is in thermal contact with the contact member 9 also becomes low temperature. Then, the temperature at the high-temperature end 20H of the second pulse tube 20 in thermal contact with the second heat sink 21 also becomes low, reaching a temperature almost similar to that at the low-temperature end 14L of the first pulse tube 14 .

According to this embodiment, because the temperature of the high temperature end 20H of the second pulse tube 20 is kept at a low temperature by the function of the second radiator 21 , it is beneficial to reduce the gas volume of the refrigerant gas in the second pulse tube 20 . At the same time, the length of the second pulse tube 20 is relatively shorter than the length of the second pulse tube in the prior art, which is beneficial to realize the miniaturization of the second pulse tube 20 .

As described above, according to the present embodiment, the second buffer tank 23 is disposed in the vacuum insulation chamber 24W of the vacuum insulation tank 24, so that the thermal contact between the second buffer tank 23 and the air can be suppressed, and the second buffer tank 23 can always be maintained. In the low temperature state, it is beneficial to improve the refrigeration capacity of the pulse tube refrigerator.

In particular, as shown in FIG. 1 , a second buffer tank 23 is provided in a shield chamber 26W of a shield case 26 that is located in the vacuum insulation tank 24 and has good insulating performance. In this way, the temperature of the second buffer tank 23 can be lowered. Accordingly, the refrigerant gas in the second buffer tank 23 can also be kept at a low temperature.

Therefore, according to this embodiment, it is beneficial to further increase the compression ratio of the refrigerant gas in the refrigeration circuit, increase the amount of refrigeration generated at the low-temperature end 20L of the second pulse tube 20, and improve the refrigeration capacity of the pulse tube refrigerator.

Furthermore, according to the present embodiment, the second inertia tube 22 for flowing in and out of the refrigerant gas to and from the second buffer tank 23 is provided together with the second buffer tank 23 in the vacuum insulation chamber 24W of the vacuum insulation tank 24 . In this way, not only the thermal contact between the second buffer tank 23 and the air can be suppressed, but also the thermal contact between the second inertia tube 22 and the air can be suppressed, so that the second inertia tube 22 can always be in a low temperature state. Therefore, according to this embodiment, it will be beneficial to further increase the compression ratio of the refrigerant gas in the refrigeration circuit, thereby increasing the amount of refrigeration generated at the low-temperature end 20L of the second pulse tube 20 .

Especially the 2nd inertial tube 22, as shown in Figure 1, owing to be arranged in the shielding chamber 26W of the vacuum insulation tank 24 shielding cover 26, can make the temperature of the 2nd inertial tube 22 keep in lower state, thus the 2nd inertial tube 22 The temperature of the refrigerant gas in the pipe 22 can be kept at a lower state. Therefore, according to this embodiment, it will be beneficial to further increase the compression ratio of the refrigerant gas in the refrigeration circuit, thereby increasing the amount of refrigeration generated at the low-temperature end 20L of the second pulse tube 20 .

Furthermore, according to the present embodiment, the shield plate 25 serving as a cooling device is cooled at the low-temperature end 14L of the first pulse tube 14 , and the second inertial tube 22 is in thermal contact with the shield plate 25 . Therefore, the second inertial tube 22 is cooled by the shield plate 25 by utilizing the freezing effect generated at the low-temperature end 14L of the first pulse tube 14 . In particular, since the inner diameter of the flow path of the second inertial tube 22 is small, not only the refrigerant gas flowing on the peripheral side of the second inertial tube 22, but also the refrigerant gas flowing on the central axis side of the second inertial tube 22 can also pass through the shielding plate 25 to cool down. Therefore, the entire refrigerant gas flowing through the second inertial tube 22 can be effectively cooled.

That is to say, according to this embodiment, due to the cooling effect of the cooling device shielding plate 25, the refrigerant gas in the second inertial tube 22 can be effectively cooled, so the refrigerant gas flowing in the second inertial tube 22 can be kept at lower temperature state. In this way, it will be beneficial to further increase the compression ratio of the refrigerant gas in the refrigeration circuit, so that the high temperature end 20H of the second pulse tube 20 is further in a low temperature state, and the amount of refrigeration generated at the low temperature end 20L of the second pulse tube 20 is further increased.

Also, since the refrigerant gas flowing in the second inertial tube 22 can be kept at a lower temperature state, the flow path resistance of the second inertial tube 22 becomes smaller, and the viscous loss of the gas flowing in the second inertial tube 22 can be reduced. . As a result, the phase and amount of the refrigerant gas flowing through the high temperature end 20H of the second pulse tube 20 can be kept in good condition, thereby increasing the refrigeration capacity.

As described above, if the refrigerant gas in the second inertial tube 22 can be cooled on the low temperature side, then the peak of the gas pressure resonance frequency in the second buffer tank 23 and the second inertial tube 25 can be clarified. This will help to further increase the amount of freezing generated at the second pulse tube 20 and the low temperature end 20L.

Furthermore, according to the present embodiment, the second buffer tank 23 and the shield plate 25 are in thermal contact. And the shielding plate 25 as a cooling device is in thermal communication with the low temperature end 14L of the first pulse tube 14 . Therefore, the second buffer tank 23 is cooled by the cooling action generated at the low temperature end 14L of the first pulse tube 14 through the shield plate 25 . Therefore, the temperature of the refrigerant gas in the second buffer tank 23 can be kept lower. This will help to further increase the compression ratio of the refrigerant gas in the refrigeration circuit, so that the high-temperature end 20H of the second pulse tube 20 is further in a low-temperature state, and further increases the amount of refrigeration generated at the low-temperature end 20L of the second pulse tube 20 .

As described above, according to this embodiment, it is beneficial to increase the compression ratio of the refrigerant gas in the refrigeration circuit, and make the volume of the second pulse tube 20 relatively smaller than that of the prior art. This shortens the length of the second pulse tube 20 . It is beneficial to suppress the vibration of the second pulse tube 20, so that the pulse tube refrigerator is suitable for use in a vibration environment.

According to the above-mentioned embodiment, as shown in FIG. 1, the second heat sink 21 disposed at the high temperature end 20H of the second pulse tube 20 is in thermal contact with the contact member 9, but it is not limited thereto, and the second heat sink can also be 21 is in direct thermal contact with the low temperature end 14L of the first pulse tube 14 .

Although the above-mentioned embodiment is an example applicable to a two-stage pulse tube refrigerator, it is not limited thereto, and may be applied to a three-stage or higher pulse tube refrigerator.

(second embodiment)

Fig. 3 shows a second embodiment. The second embodiment is a modified form of the first embodiment. The second embodiment has basically the same structure as the first embodiment, and has the same functions and effects. Common symbols have been added to common parts. Only the parts that are different from the first embodiment will be mainly described below. That is, one sub-cooler 40 is provided between the first heat exchanger 15 and the piping 13 in the first embodiment. And the shielding plate 25 as a cooling device is provided in contact with the high temperature end of the sub-cooler 40 . so. According to the second embodiment, the freezing temperature generated by the low-temperature end 14L of the first pulse tube 14 can be very low, and the temperature of the high-temperature end 20H of the second pulse tube 20 can be higher than the temperature of the low-temperature end 14L of the first pulse tube 14 applicable to the circumstances.

(third embodiment)

Fig. 4 shows a third embodiment. The third embodiment is a modified form of the first embodiment. The third embodiment has basically the same structure as the first embodiment, and basically has the same functions and effects. Common symbols have been added to common parts. Only the parts different from those of the first embodiment will be mainly described below. That is, as shown in FIG. 4 , the second buffer tank 23 is in thermal contact with the shielding plate 25 as a cooling device, and is cooled by the cooling action generated at the low temperature end 14L of the first pulse tube 14 through the shielding plate 25 . In this way, the refrigerant gas in the second buffer tank 23 can be kept at a lower temperature. As shown in FIG. 4, the shielding plate 25 is bent against the second buffer tank 23, and has a flange 25r that is in thermal contact with the outer wall surface of the second buffer tank 23 and can promote heat transfer. The flange 25r for promoting heat transfer is to increase the contact portion (heat transfer area) with the second buffer tank 23 to improve the cooling performance of the refrigerant gas in the second buffer tank 23 .

(fourth embodiment)

Fig. 5 shows a fourth embodiment. The fourth embodiment is a modified form of the first embodiment. Fourth Embodiment The first embodiment has basically the same structure and basically the same function and effect. Common symbols have been added to common parts. Only the parts that are different from the first embodiment will be mainly described below. That is: although most of the second buffer tank 23 is disposed in the vacuum insulation chamber 24W of the vacuum insulation tank 24, only a part (upper end) of the second buffer tank 23, as shown in FIG. Out in the heat groove 24. However, in the second buffer tank 23, a heat insulating material 23m with good heat insulating performance is disposed on all parts exposed from the vacuum heat insulation tank 24. The heat insulating material 23m can suppress the temperature rise of the refrigerant gas in the second buffer tank.

(fifth embodiment)

FIG. 6 shows a fifth embodiment, which is a modified form of the first embodiment. The sixth embodiment has basically the same structure as the first embodiment, and basically has the same functions and effects. Common symbols have been added to common parts. Only the parts that are different from the first embodiment will be mainly described below. That is, although the second buffer tank 23 is installed in the vacuum heat insulation chamber 24W of the vacuum heat insulation tank 24 , only the tubular portion 23X protruding from the second buffer tank 23 is exposed from the vacuum heat insulation tank 24 . Measuring instruments 23K such as sensors for detecting physical quantities such as pressure and temperature of the refrigerant gas in the second buffer tank 23 may be installed in the tubular portion 23X as required. Since the measuring instrument 23K is exposed from the vacuum insulation tank 24, it is beneficial to the maintenance and repair of the measuring instrument 23K.

(sixth embodiment)

Fig. 7 shows a sixth embodiment. The sixth embodiment is a modified form of the first embodiment. The structure of the sixth embodiment is basically the same as that of the first embodiment, and basically the same functions and effects are achieved. Common symbols have been added to common parts. Only the parts that are different from the first embodiment will be mainly described below. That is: when the length of the second inertial tube 22 is long, in order to effectively utilize the second inertial tube 22, the whole or part of the second inertial tube 22 can be wound around the low temperature end 14L of the first pulse tube 14 along its circumferential direction. . The second inertial tube 22 is effectively cooled by utilizing the cooling effect generated at the low temperature end 14L of the first pulse tube 14 (cooling device). The second inertia tube 22 is installed in the vacuum insulation chamber 24W.

(Others) The following technical ideas can be summarized from the above contents.

Note 1: In claim 1, the pulse tube refrigerator is characterized in that: the buffer tank communicates with the high temperature end of the pulse tube through an inertial tube whose inner diameter of the flow path is relatively smaller than that of the pulse tube.

Note 2: In Note 1, the feature of the pulse tube refrigerator is that the above-mentioned inertial tube is arranged in the vacuum heat insulation chamber of the vacuum heat insulation tank.

Note 3: In Note 1 or Note 2, the pulse tube refrigerator is characterized by: the above pulse tube includes: a first pulse tube, into which a refrigerant gas with a pressure waveform flows, and one end is a low temperature end, and the other end is a high temperature end ; The second pulse tube, in which a refrigerant gas with a pressure waveform flows in, and one end is a low-temperature end whose temperature is lower than that of the first pulse tube low-temperature end, and the other end is a high-temperature end.

Remark 4: In Remark 3, the pulse tube refrigerator is characterized in that: the above-mentioned regenerator is arranged between the above-mentioned pressure waveform generating device and the above-mentioned first pulse tube and the above-mentioned second pulse tube, and the flow into the above-mentioned first pulse tube and/or Or the refrigerant gas in the second pulse tube is pre-cooled.

Note 5: In Note 3, the feature of the pulse tube refrigerator is that the above-mentioned pressure waveform phase control device has: a first inertia tube, which communicates with the high-temperature end of the above-mentioned first pulse tube, and the inner diameter of the flow path is smaller than the above-mentioned first The inner diameter of the pulse tube; the first buffer tank, which communicates with the high temperature end of the first pulse tube through the first inertia tube; the second inertia tube, which communicates with the high temperature end of the second pulse tube, and the inner diameter of the flow path is less than The inner diameter of the second pulse tube; the second buffer tank on the low temperature side, which communicates with the high temperature end of the second pulse tube through the second inertial tube.

Supplementary Note 6: In Supplementary Note 5, the feature of the pulse tube refrigerator is that it is provided with a cooling device that is in thermal contact with the low-temperature end of the above-mentioned first pulse tube and utilizes the freezing effect from the low-temperature end of the above-mentioned first pulse tube for cooling, and The cooling device is brought into thermal contact with the second inertia tube.

Note 7: In Note 5 or Note 6, the pulse tube refrigerator is characterized in that it is provided with a cooling device that is in thermal contact with the low-temperature end of the above-mentioned first pulse tube and uses the freezing effect from the low-temperature end of the above-mentioned first pulse tube for cooling , and make the above-mentioned cooling device thermally contact with the above-mentioned second buffer tank.

Note 8: In Notes 5-7, the pulse tube refrigerator is characterized in that at least a part of the second inertia tube is in thermal contact with the low temperature end of the first pulse tube.

Industrial availability

The invention can be utilized in pulse tube refrigerators.

Claims (5)

1. A pulse tube refrigerator, comprising: A pressure waveform generating device, which causes the refrigerant gas to generate a pressure waveform; A pulse tube, in which the refrigerant gas with a pressure waveform generated by the above-mentioned pressure waveform generating device flows into it, and one end is a low-temperature end, and the other end is a high-temperature end; A cold accumulator, which is arranged between the above-mentioned pressure waveform generating device and the above-mentioned pulse tube, and pre-cools the refrigerant gas flowing into the above-mentioned pulse tube; A pressure waveform phase controller, which has a buffer tank connected to the high temperature end of the pulse tube, and controls the pressure waveform phase of the refrigerant gas, thereby generating a cooling effect at the low temperature end of the pulse tube; a vacuum heat insulation tank having a vacuum heat insulation chamber for accommodating the above-mentioned pulse tube, The pulse tube refrigerator is characterized by: The above-mentioned buffer tank is arranged in the above-mentioned vacuum heat insulation chamber of the above-mentioned vacuum heat insulation tank. 2. A pulse tube refrigerator, comprising; A pressure waveform generating device, which causes the refrigerant gas to generate a pressure waveform; In the pulse tube, the refrigerant gas with pressure waveform generated by the pressure waveform generating device flows into it, and one end is a low-temperature end and the other end is a high-temperature end. A cold accumulator, which is arranged between the above-mentioned pressure waveform generating device and the above-mentioned pulse tube, and pre-cools the refrigerant gas flowing into the above-mentioned pulse tube; A pressure waveform phase controller, which has an inertial tube connected to the high temperature end of the pulse tube and whose inner diameter of the flow path is smaller than the inner diameter of the pulse tube, and a buffer tank connected to the high temperature end of the pulse tube through the inertial tube, and its The pressure waveform phase of the refrigerant gas is controlled to produce a cooling effect at the low temperature end of the pulse tube; a vacuum heat insulation tank having a vacuum heat insulation chamber for accommodating the above-mentioned pulse tube, The pulse tube refrigerator is characterized by: The above-mentioned inertia tube is arranged in the above-mentioned vacuum heat insulation chamber of the above-mentioned vacuum heat insulation tank. 3. A pulse tube refrigerator, comprising: A pressure waveform generating device, which causes the refrigerant gas to generate a pressure waveform; The first pulse tube, in which the refrigerant gas with pressure waveform generated by the above-mentioned pressure waveform generating device flows into, and one end is a low-temperature end, and the other end is a high-temperature end; A second pulse tube, in which a refrigerant gas with a pressure waveform flows in, and one end is a low temperature end lower than the low temperature end of the first pulse tube, and the other end is a high temperature end; A regenerator, which is arranged between the above-mentioned pressure waveform generating device and the above-mentioned first pulse tube and the above-mentioned second pulse tube, and pre-cools the refrigerant gas flowing into the above-mentioned first pulse tube and/or the above-mentioned second pulse tube; The pressure waveform phase controller has: a first inertia tube connected to the high temperature end of the first pulse tube and having a flow path inner diameter smaller than the inner diameter of the first pulse tube; through the first inertia tube and the first pulse tube high temperature The first buffer tank connected at the end; the second inertial tube connected with the high temperature end of the second pulse tube, and the inner diameter of the flow path is smaller than the inner diameter of the second pulse tube; through the second inertial tube and the second pulse tube The high-temperature end is connected to the second buffer tank, and the phase of the pressure waveform of the refrigerant gas is controlled to produce a cooling effect; A vacuum insulation tank comprising a vacuum insulation chamber for accommodating at least the second pulse tube, The pulse tube refrigerator is characterized by: A cooling device is provided, and the cooling device is in thermal contact with the second inertial tube, the cooling device is in thermal contact with the low temperature end of the first pulse tube, and is cooled by the freezing effect from the low temperature end of the first pulse tube . 4. A pulse tube refrigerator, comprising: A pressure waveform generating device, which causes the refrigerant gas to generate a pressure waveform; The first pulse tube, in which the refrigerant gas with pressure waveform generated by the above-mentioned pressure waveform generating device flows into, and one end is a low-temperature end, and the other end is a high-temperature end; The second pulse tube, in which a refrigerant gas with a pressure waveform flows into it, and one end is a low-temperature end lower than the low-temperature end of the first pulse tube, and the other end is a high-temperature end; A regenerator, which is arranged between the above-mentioned pressure waveform generating device and the above-mentioned first pulse tube and the above-mentioned second pulse tube, and pre-cools the refrigerant gas flowing into the above-mentioned first pulse tube and/or the above-mentioned second pulse tube; The pressure waveform phase controller includes: a first inertia tube connected to the high temperature end of the first pulse tube and having a flow path inner diameter smaller than the inner diameter of the first pulse tube; The first buffer tank connected at the end; the second inertia tube connected with the high temperature end of the above-mentioned second pulse tube, and the inner diameter of the flow path is smaller than the inner diameter of the second pulse tube; through the above-mentioned second inertia tube and the above-mentioned second pulse tube The high-temperature end is connected to the second buffer tank, and the phase of the pressure waveform of the refrigerant gas is controlled to produce a cooling effect; A vacuum insulation tank comprising a vacuum insulation chamber for accommodating at least the second pulse tube, The pulse tube refrigerator is characterized by: A cooling device is provided, and the cooling device is in thermal contact with the second buffer tank, the cooling device is in thermal contact with the low-temperature end of the first pulse tube, and is cooled by the freezing effect from the low-temperature end of the first pulse tube . 5. A pulse tube refrigerator, comprising: A pressure waveform generating device, which causes the refrigerant gas to generate a pressure waveform; The first pulse tube, in which the refrigerant gas with pressure waveform generated by the above-mentioned pressure waveform generating device flows into, and one end is a low-temperature end, and the other end is a high-temperature end; The second pulse tube, in which a refrigerant gas with a pressure waveform flows in, and one end is a low-temperature end whose temperature is lower than that of the first pulse tube low-temperature end, and the other end is a high-temperature end; A regenerator, which is arranged between the pressure waveform generating device and the first pulse tube and the second pulse tube, and precools the refrigerant gas flowing into the first pulse tube and the second pulse tube; The pressure waveform phase controller has: a first inertia tube connected to the high temperature end of the first pulse tube and having a flow path inner diameter smaller than the inner diameter of the first pulse tube; through the first inertia tube and the first pulse tube high temperature The first buffer tank connected at the end; the second inertia tube connected with the high temperature end of the above-mentioned second pulse tube, and the inner diameter of the flow path is smaller than the inner diameter of the second pulse tube; through the above-mentioned second inertia tube and the above-mentioned second pulse tube The high-temperature end is connected to the second buffer tank, and the phase of the pressure waveform of the refrigerant gas is controlled to produce a cooling effect; A vacuum insulation tank comprising a vacuum insulation chamber for accommodating at least the second pulse tube, The pulse tube refrigerator is characterized by: At least a part of the second inertia tube is in thermal contact with the low temperature end of the first pulse tube.

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