JP2005265261A - Pulse pipe refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulse pipe refrigerator of U-return type in which the performance is improved to a large extent by conducting a heat exchange with a working gas having lowest temperature in a fold-back space and decreasing the thermal loss by suppressing the expansion of the working gas as much as practicable. <P>SOLUTION: The pulse pipe refrigerator of U-return type consists of a coldness accumulator 30, a cold head 40, and a pulse pipe 50 which are arranged approximately in a U-shape, wherein a plurality of intra-space heat-exchange members 44 are installed in the fold-back space 42 of the cold head 40, and a flow passage 45 is formed leading from the coldness accumulator 30 to the pulse pipe 50. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a U-shaped return type pulse tube refrigerator.

A conventional pulse tube refrigerator will be described with reference to the drawings.
FIG. 14 is a schematic configuration diagram of a conventional U-shaped return type pulse tube refrigerator. The pulse tube refrigerator 100 includes a compressor 10, an aftercooler 20, a regenerator 30, a cold head 40, a pulse tube 50, a high temperature end 60, and a phase control unit 70.

The compressor 10 includes a cylinder 11 and a piston 12.
The aftercooler 20 includes a heat exchanger 21 and a radiator 22.
The cold head 40 includes a conductive block 41, a folded space 42, and a low temperature heat exchanger 43.
The high temperature end 60 includes a high temperature heat exchanger 61 and a high temperature radiator 62.
The phase control unit 70 includes an inertance tube 71 and a buffer tank 72.

  In such a pulse tube refrigerator 100, a flow path is formed. For example, helium is sealed as working gas (refrigerant gas) in the flow path. When the pulse tube refrigerator 100 is operated, the piston 12 reciprocates at a predetermined frequency in the cylinder 11 of the compressor 10, so that the working gas in the cylinder 11 is compressed and expanded. Such a working gas flows as a reciprocating flow from the compressor 10 through the aftercooler 20, the regenerator 30, the cold head 40, the pulse tube 50, and the high temperature end 60 to the phase control unit 70.

Next, the principle of refrigeration generation in the pulse tube refrigerator 100 will be described briefly. The refrigeration generation principle of the pulse tube refrigerator 100 is understood as follows.
First, in the compressor 10, the piston 12 compresses the working gas in the cylinder 11, and outputs this compressed working gas. This working gas flows into the aftercooler 20. When the working gas passes through the heat exchanger 21 of the aftercooler 20, the heat exchanger 21 exchanges heat with the heat and conducts heat to the radiator 22. And the heat radiator 22 discharge | releases this heat outside (1st process: adiabatic compression process).
The working gas that has flowed out of the aftercooler 20 passes through the regenerator 30 and the cold head 40 and flows into the pulse tube 50 (second stroke: isothermal stroke).
The working gas expands in the pulse tube 50 to generate cold (third process: adiabatic expansion process). The generated cold is absorbed by a low-temperature heat exchanger 43 provided in the cold head 40.
In the high temperature heat exchanger 61 at the high temperature end 60, the high temperature heat exchanger 61 exchanges heat of the working gas and conducts heat to the high temperature radiator 62. The high temperature radiator 62 releases heat to the outside. Subsequently, in the phase controller 70, the working gas flows in the inertance tube 71 and the buffer tank 72 with a pressure amplitude almost sinusoidally, and a phase difference is generated between the pressure change and the flow rate change of the working gas. generate.
Next, when the compressor 10 expands, the working gas cooled by the pulse tube 50 returns to the compressor 10 through the after cooler 20 while performing quasi-static heat exchange with the regenerator 30 ( Fourth stroke: isothermal stroke).
By repeating the above four steps, the cold head 40 is cooled to a very low temperature.

  A folded space 42 is formed inside the cold head 40 of the U-shaped return type pulse tube refrigerator 100. The folded space 42 is provided as a space in the conduction block 41 as shown in FIG. 14, or is provided as a simple space, such as a simple bent circular pipe (not shown). Yes. Therefore, the generated cold is absorbed by only the low-temperature heat exchanger 43 installed immediately before the inflow of the pulse tube 50.

As another prior art example, Patent Document 1 discloses a pulse tube refrigerator in which a fin-like heat exchange member is attached to a low temperature end (corresponding to a cold head).
JP 11-182957 A (paragraph numbers 0010 to 0019, FIGS. 1 to 4)

  Classically, thermodynamics is performed at the boundary surface that transitions from the second stroke (isothermal stroke) to the third stroke (adiabatic expansion stroke), that is, at the low-temperature heat exchanger 43 of the cold head 40. However, when the folded space 42 is provided as in the U-shaped return-type pulse tube refrigerator 100, the working gas starts to expand gradually in the folded space 42 and is activated when it reaches the low-temperature heat exchanger 43. The gas temperature has risen slightly. Therefore, when heat exchange is performed only with the low-temperature heat exchanger 43, the temperature of the cold head 40 as a whole also rises through the conduction block 41, causing a problem of causing a thermal loss and reducing the performance of the entire refrigerator. .

  Therefore, the present invention has been made in view of the above problems, and its purpose is to perform heat exchange with the coldest working gas in the folded space and to suppress the expansion of the working gas as much as possible. The object is to provide a U-shaped return type pulse tube refrigerator with reduced thermal loss and greatly improved performance.

In order to solve the above problems, a pulse tube refrigerator of the invention according to claim 1 of the present invention provides:
A compressor, a regenerator, a cold head, a pulse tube, and a phase control unit are connected so that a regenerator, a cold head, and a pulse tube are connected in a substantially U shape to form a U-shaped return type flow path. In a U-shaped return type pulse tube refrigerator that generates cold in the cold head by heat exchange with the working gas flowing through the return type flow path,
A heat exchanger formed in the folding space of the cold head;
A flow path divided and formed by the heat exchanger and the cold head so as to communicate between the regenerator side and the pulse tube side;
It is characterized by providing.

The pulse tube refrigerator of the invention according to claim 2 of the present invention is
The pulse tube refrigerator according to claim 1, wherein
In the heat exchanger, a plurality of linear space heat exchange members are provided substantially in parallel with the flow passage directions on the regenerator side and the pulse tube side, and two adjacent space heat exchange members and a cold head are used. It is a heat exchanger in which a plurality of substantially linear flow paths are formed.

The pulse tube refrigerator of the invention according to claim 3 of the present invention is
In the pulse tube refrigerator according to claim 2,
The heat exchanger is a heat exchanger in which an in-space heat exchange member is arranged so that the flow path intervals are the same on the regenerator side and the pulse tube side.

The pulse tube refrigerator of the invention according to claim 4 of the present invention is
In the pulse tube refrigerator according to claim 2,
The heat exchanger is a heat exchanger in which an in-space heat exchange member is arranged so that a flow path interval is narrow in a long flow path and a flow path interval is wide in a short flow path. .

The pulse tube refrigerator of the invention according to claim 5 of the present invention is
The pulse tube refrigerator according to claim 1, wherein
In the heat exchanger, a plurality of linear space heat exchange members are provided radially around the pulse tube side, and a substantially linear flow path is formed radially by two adjacent space heat exchange members and a cold head. A plurality of heat exchangers are formed.

Moreover, the pulse tube refrigerator of the invention according to claim 6 of the present invention,
In the pulse tube refrigerator according to claim 5,
The heat exchanger is a heat exchanger in which an in-space heat exchange member is arranged so that the flow path interval is wide on the regenerator side and the flow path interval is narrow on the pulse tube side. .

The pulse tube refrigerator of the invention according to claim 7 of the present invention is
In the pulse tube refrigerator according to claim 5,
The heat exchanger is a heat exchanger in which an in-space heat exchange member is arranged so that the gas channel opening ratio (= gas channel cross-sectional area / total cross-sectional area) is constant on the regenerator side and the pulse tube side. It is characterized by being.

The pulse tube refrigerator of the invention according to claim 8 of the present invention is
In the pulse tube refrigerator according to any one of claims 2 to 7,
The in-space heat exchange member is a linear member that is a solid body having a rectangular cross section or a triangular cross section.

Moreover, the pulse tube refrigerator of the invention according to claim 9 of the present invention,
In the pulse tube refrigerator according to any one of claims 2 to 7,
The in-space heat exchanging member is a corrugated member that is a plate having a sinusoidal section, a triangular section, or a rectangular section, and a plurality of in-space heat exchanging members are integrally formed.

The pulse tube refrigerator of the invention according to claim 10 of the present invention is
In the pulse tube refrigerator according to any one of claims 2 to 7,
The in-space heat exchange member is a hollow tubular member.

Moreover, the pulse tube refrigerator of the invention according to claim 11 of the present invention is
The pulse tube refrigerator according to claim 1, wherein
The heat exchanger is a heat exchanger provided with a plurality of pin-shaped in-space heat exchange members so as to protrude in a substantially vertical direction with respect to the flow path direction on the regenerator side and the pulse tube side. To do.

A pulse tube refrigerator of the invention according to claim 12 of the present invention is
The pulse tube refrigerator according to claim 11, wherein
The heat exchanger is characterized in that a large number of pin-shaped heat exchange members in a space are arranged in a parallel and parallel arrangement to form a lattice flow path.

A pulse tube refrigerator of the invention according to claim 13 of the present invention is
The pulse tube refrigerator according to claim 11, wherein
The heat exchanger is characterized in that a large number of pin-shaped in-space heat exchange members are arranged in a staggered arrangement to form a worm-like flow path.

The pulse tube refrigerator of the invention according to claim 14 of the present invention is
The pulse tube refrigerator according to claim 11, wherein
In the heat exchanger, a number of pin-shaped heat exchangers in the space are arranged in a constant aperture ratio arrangement, and the gas channel opening ratio (= gas channel cross-sectional area / total cross-sectional area) on the regenerator side and the pulse tube side. ) Is formed as a constant flow path.

A pulse tube refrigerator of the invention according to claim 15 of the present invention is
In the pulse tube refrigerator according to any one of claims 11 to 14,
The in-space heat exchanging member has a pin shape of a cylinder, a polygonal column, a cone, or a polygonal pyramid.

In the present invention, a heat exchanger is also installed in the folding space of the cold head to actively exchange heat with the coldest working gas (working gas in the vicinity of the regenerator), and the flow of the pulse tube in the folding space. It was set as the structure which suppresses expansion | swelling of working gas until it flows into an inlet_port | entrance.
According to the present invention as described above, heat exchange with the coldest working gas in the folded space is performed, and the thermal loss generated in the cold head is greatly reduced by suppressing the expansion of the working gas as much as possible. Therefore, it is possible to provide a U-shaped return type pulse tube refrigerator that is greatly reduced in performance.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings. This embodiment is novel in that the cold head 40 is improved in the pulse tube refrigerator 100 of FIG. Hereinafter, the cold head 40 will be mainly described, and the other portions are the same as those of the prior art, and redundant description thereof will be omitted.

  FIG. 1 is a schematic view of the vicinity of the cold head of the pulse tube refrigerator of this embodiment. This embodiment relates to inventions according to claims 1 and 2. In this embodiment, the heat exchanger is provided in the folded space 42. In this heat exchanger, a plurality of (five in FIG. 1) space heat exchange members 44 are attached to the conduction block 41 of the cold head 40 after securing thermal conductivity by screw fastening, brazing, and welding, or It is provided by being integrally formed with the conduction block 41. In such a heat exchanger, there are a plurality of flow paths 45 that communicate between the regenerator 30 side and the pulse tube 50 side in the folded space 42 that is a flow path in the cold head 40 and through which the working gas flows (see FIG. 6 in 1). One flow path 45 is partitioned by two adjacent in-space heat exchange members 44 and the conduction block 42 and is formed in a substantially linear shape. The material of the in-space heat exchange member 44 is generally a highly conductive copper. These in-space heat exchanging members 44 are in thermal contact with the regenerator 30, the low temperature heat exchanger 43, and the conduction block 41 on the upper side as well as the lower side. In this lower side, the space heat exchange member 44 may not be thermally connected to the regenerator 30 and the low temperature heat exchanger 43. Although not shown, the space heat exchange member 44 is located above the conduction block 41. It is also possible to have a structure in which only the surfaces are in thermal contact with each other and have a slight gap on the lower side.

In such a folding space 42, from the lowest temperature gas immediately after the outlet of the regenerator 30 to the low temperature gas at the inlet of the pulse tube 50 that has slightly increased in temperature, it contacts the heat exchange member 44 in the space, and in the entire area of the folding space 42. Force heat exchange with working gas. In this way, heat exchange can be performed in the entire cold head 40.
In this embodiment, heat exchange can be performed at the average temperature of the entire inside of the cold head 40, and a rapid change in the working gas temperature can be suppressed. As a result, the temperature of the cold head 40 can be further lowered and the refrigeration output at the specified temperature is improved as compared with the case where heat is exchanged only at the temperature near the inlet of the pulse tube 50 as in the prior art.

  Next, a more specific form of this embodiment will be described. FIG. 2 is an explanatory view of the arrangement of the heat exchange members in the space of the cold head of the pulse tube refrigerator of the present embodiment. This embodiment relates to an invention according to claim 3. In this embodiment, a plurality of linear (bar-shaped) in-space heat exchange members 44 are installed in the folded space 42 of the cold head 40 to form a flow path 45 through which the working gas flows. In particular, the in-space heat exchange members 44 are arranged in parallel so that the flow path intervals are the same on the regenerator 30 side and the pulse tube 50 side. For example, the heat exchanger is formed by a parallel equidistant arrangement in which the heat exchange members 44 in the space a and the flow paths 45 in the distance b are alternately arranged.

  1 and 2, since the regenerator 30 has a large diameter and the pulse tube 50 has a small diameter, in order to arrange the heat exchange members 44 in the space in parallel, they are arranged in a plurality of rows. Out of the space heat exchange member 44, the outside heat exchange member 44 needs to be shorter in the flow path direction, and the inside heat exchange member 44 needs to be formed longer in the flow path direction. The material of the in-space heat exchange member 44 is generally a highly conductive copper. These in-space heat exchange members 44 are in thermal contact with the regenerator 30, the low temperature heat exchanger 43, and the conduction block 41 on the lower side. Although not shown in the drawings, the space heat exchange member 44 may be thermally connected by contacting the surface only on the upper side of the conduction block 41 and not thermally connected with a gap on the lower side.

  In this embodiment, the flow path interval is made constant, the pressure loss inside the cold head 40 is reduced, and the overall efficiency of the pulse tube refrigerator 100 is improved. In the heat exchanger, the space heat exchange members 44 in the space a and the flow channels 45 in the space b are alternately arranged. For example, the flow channel 45 is cut with an end mill having a diameter b by a milling machine and integrated with the conductive block 41. Advantages such as being able to be formed can be expected and manufacturing is easy.

  Subsequently, another embodiment will be described. FIG. 3 is an explanatory view of the arrangement of the heat exchange members in the space of the cold head of the pulse tube refrigerator of the present embodiment. This embodiment relates to an invention according to claim 4. Also in this embodiment, a plurality of rod-shaped in-space heat exchange members 44 are installed in the folded space 42 of the cold head 40 to form a flow path 45 through which the working gas flows. In particular, among the in-space heat exchange members 44 arranged in a plurality of rows on the regenerator 30 side and the pulse tube 50 side, the long channel 45 has a narrow channel interval, and the short channel 45 has a large channel interval. The in-space heat exchange member 44 is arranged.

  For example, as described above, as shown in FIGS. 1 and 2, the regenerator 30 has a large diameter and the pulse tube 50 has a small diameter, so that the in-space heat exchange members 44 are arranged in parallel. Among the in-space heat exchange members 44 arranged in a plurality of rows, it is necessary to form the in-space heat exchange member 44 short in the flow path direction on the outside and the in-space heat exchange member 44 long in the flow path direction on the inside. is there. In this case, the flow path is arranged so that it is narrow inside the long channel and wide on the outside where the channel is short. There are innumerable arrangements, but, for example, the in-space heat exchange members 44 are arranged in parallel so that the intervals between the flow channels 45 are b, 1.2b, 1.4b, 1.6b. It is.

  The material of the in-space heat exchange member 44 is generally a highly conductive copper. These space heat exchange members 44 are in thermal contact with the regenerator 30, the low temperature heat exchanger 43 and the conduction block 41 on the lower side. Although not shown in the drawings, the space heat exchange member 44 may be thermally connected by contacting the surface only on the upper side of the conduction block 41 and not thermally connected with a gap on the lower side.

In this embodiment, the flow resistance between the flow paths 45 (between the members) is made equal by adjusting the flow path spacing between the heat exchange members 44 in the space, and the flow bias when flowing into the pulse tube 50 is made uniform. It is a structure to lose. Next, the principle of eliminating such a flow bias will be described analytically.
Generally, the pressure loss of a one-way flow pipe is expressed by the following equation using the fluid resistance coefficient R, gas density ρ, pipe friction resistance λ, pipe hydraulic diameter d, pipe length L, and flow velocity v. expressed.

  Further, the pressure loss when the joining of the pipes occurs is expressed by the following expression using a loss coefficient ζ (a coefficient determined by the pipe angle at the time of joining and the flow rate ratio before and after joining).

Then, it demonstrates, referring a figure using the above description. 4A and 4B are explanatory diagrams of fluid resistance. FIG. 4A is a schematic diagram of a confluent pipe having an equal cross-sectional area, FIG. 4B is a schematic diagram of a straight pipe having an equal cross-sectional area, and FIG. FIG. 4 (d) is an equivalent circuit diagram of a straight pipe. 4A and 4B, for example, the pipe diameters are all equal, and the length of the merged pipe is set to L / 2 with respect to the length L of the straight pipe. Further, when the outlet flow velocity v is constant and the inlet flow velocities of the two pipes before joining are equal to v / 2, the ζ of the above formula 2 is about 0.5. From the above _equation 1, the fluid resistance R ₀ of the straight pipe is as follows.

  The combined resistance R ′ of the junction tube is collectively expressed by the following equation.

When these R ₀ and R ′ are equal, the fluid resistance of both is the same, and no contradiction arises when the flow rates on the outlet side are equal. From Equation 3 and Equation 4, the following relationship is derived.

When the friction coefficient λ = 0.01, L / d = 33.3 is obtained from the above equation (5). Here, when L / d <33.3, the fluid resistance R ′ on the merging pipe side is larger. That is, in order to make each flow resistance equal when viewed from the outlet on the pulse tube 50 side, it is necessary to increase the flow channel interval (hydraulic diameter) on the merge tube side to reduce the fluid resistance R ′. Conversely, when L / d> 33.3, the fluid resistance R ₀ of the straight pipe becomes larger, so it is only necessary to relatively increase the flow path distance on the straight pipe side to reduce the fluid resistance.
In general, when the relationship between the length L, the diameter d, and the friction coefficient λ is L / d <1 / (3λ), the space between the heat exchange members in the space is narrow on the inner side (straight pipe side) and the outer side (merging) When L / d> 1 / (3λ), the space between the heat exchange members in the space is wide on the inner side (straight pipe side) and toward the outer side (merging pipe side). It is desirable to configure the cold head by gradually installing it narrowly.
(If ex. L = 20 mm, d = 1 mm, L / d = 20 <33.3, and the fluid resistance R ′ on the merging tube side is larger. (It is necessary to adjust by reducing the fluid resistance R ′ on the confluence pipe side.)

  In this way, by adjusting the channel spacing of the channels 45, the fluid resistance of each channel 45 (between members) is made equal to eliminate the uneven flow when flowing into the pulse tube 50, and the working gas can be efficiently used. Can be passed through. Such an arrangement may be adopted.

Subsequently, another embodiment will be described. FIG. 5 is an explanatory view of the arrangement of the heat exchange members in the space of the cold head of the pulse tube refrigerator of the present embodiment. This embodiment relates to the inventions according to claims 1, 5, and 6. In this embodiment, the heat exchanger is provided with a plurality of in-space heat exchange members 44 that are linear (bar-shaped) and have the same member spacing over the entire length in a radial manner around the pulse tube 50 side. The heat exchanger is provided with a plurality of flow paths 45 formed by 44. Furthermore, the space interval is changed at a constant rate, and the space heat exchange member having the same length is formed so that the space between the flow channels 45 is wide on the regenerator 30 side and the space between the flow channels 45 is narrow on the pulse tube 50 side. This is a heat exchanger in which a plurality of 44 are arranged.
The material of the in-space heat exchange member 44 is generally a highly conductive copper. These space heat exchange members 44 are in thermal contact with the regenerator 30, the low temperature heat exchanger 43 and the conduction block 41 on the lower side. Although not shown in the drawings, the space heat exchange member 44 may be thermally connected by contacting the surface only on the upper side of the conduction block 41 and not thermally connected with a gap on the lower side.

  In this embodiment, the flow path 45 is a radial arrangement in which the heat exchange members 44 in the space are arranged radially from the pulse tube side so that the flow path is wide on the regenerator 30 side and narrow on the pulse tube 50 side. . Thereby, the fluid resistance of all the flow paths becomes equivalent. Therefore, the uneven flow can be improved and the overall heat exchange efficiency can be improved.

Subsequently, another embodiment will be described. 6 is an arrangement explanatory diagram of the heat exchange member in the space of the cold head of the pulse tube refrigerator of the present embodiment. This embodiment relates to the inventions according to claims 1, 5 and 7. In this embodiment, the heat exchanger is provided with a plurality of in-space heat exchanging members 44 that are linear (bar-shaped) and whose member interval changes at a constant rate, with a radial centering on the pulse tube 50 side. This is a heat exchanger in which a plurality of flow paths 45 through which the working gas flows are formed by the heat exchange member 44. Furthermore, the heat exchanger in which the space heat exchanging member 44 is arranged so that the gas channel opening ratio (= gas channel cross-sectional area / total cross-sectional area) becomes a constant channel 45 on the regenerator 30 side and the pulse tube 50 side. It is.
The material of the in-space heat exchange member 44 is generally a highly conductive copper. On the lower side, these in-space heat exchange members 44 are in thermal contact with the regenerator 30, the low-temperature heat exchanger 43, and the conduction block 41. Although not shown in the drawings, the space heat exchange member 44 may be thermally connected by contacting the surface only on the upper side of the conduction block 41 and not thermally connected with a gap on the lower side.

In particular, in this embodiment, as clearly shown in FIG. 6, the flow path 45 having a wide flow path interval on the regenerator 40 side becomes narrower as the flow path interval decreases toward the pulse tube 50 side. This is a constant aperture ratio arrangement in which the in-space heat exchanging members 44 are arranged radially from the pulse tube 50 side so that the interval between the members becomes narrower at a constant rate as it advances from the pulse tube 50 side.
In this embodiment, in addition to the fluid resistances of all the flow paths 45 being equal, the restriction of the flow paths 45 is constant (= the rate of change in fluid resistance is constant). Therefore, reducing the pressure loss inside the cold head 40 contributes to improving the overall efficiency of the pulse tube refrigerator 100.

  Then, the specific structure of the heat exchange member in space demonstrated previously is demonstrated. FIG. 7 is a structural diagram of the heat exchange member in the space of the cold head, FIG. 7A is a sectional structural view of a rectangular member, and FIG. 7B is a sectional structural view of a triangular member. This embodiment relates to an invention according to claim 8. A plurality of elongated in-space heat exchange members 44 are provided on the upper surface of the conduction block 41. The attachment may be performed by adhesion such as brazing or a fastening member such as a screw, or the conductive block 41 and the in-space heat exchanging member 44 may be integrated and fixed in a state where thermal conductivity is ensured.

  Of the shape parameters of the in-space heat exchange member 44, the main parameter related to the heat exchange performance is the hydraulic diameter when the length of the in-space heat exchange member 44 is constant. Since the performance of the pulse tube refrigerator 100 depends on the trade-off between fluid resistance and heat transfer coefficient, it is preferable to select an optimal hydraulic diameter. Therefore, the in-space heat exchanging member 44 is a rectangular member having a rectangular cross-section as shown in FIG. 7A, or a triangular member having a triangular cross-section as shown in FIG. 7B. Furthermore, the optimum fluid resistance and heat transfer coefficient are selected by adjusting the thickness of the in-space heat exchange member 44 and the interval between the flow paths 45. In addition, although the rectangular member and the triangular member were mentioned as an example as an example of the linear member, although not illustrated, a linear member having another cross-sectional shape such as a trapezoidal cross-sectional shape may be employed.

  Then, the other specific structure of the heat exchange member demonstrated previously is demonstrated. FIG. 8 is a structural diagram of the heat exchange member in the space of the cold head, FIG. 8 (a) is a cross-sectional structure diagram of the heat exchange member in the space of the sine wave plate, and FIG. 8 (b) is the heat in the space of the rectangular wave plate. It is sectional structure drawing of an exchange member. This embodiment relates to an invention according to claim 9. The in-space heat exchange member 44 of this embodiment employs a corrugated member that is a plate having a sinusoidal section, a triangular section, or a rectangular section.

  FIG. 8A shows a structure in which a crest portion of a sinusoidal plate formed by bending a thin plate of good conductivity (for example, copper) is fixed to the upper surface of the conductive block 41 by a plurality of connection layers 46. In this case, one space heat exchange member 44 is an individual mountain, and a plurality of space heat exchange members 44 are integrally formed. In such a heat exchanger, a closed flow path is formed by the conduction block 41 and the space heat exchange member 44, and the space heat exchange member 44 and the lower surface of the conduction block 41 (not shown) (the regenerator 30 / low temperature). A closed flow path is formed by including the heat exchange 43. The attachment is performed by forming the connection layer 46 by adhesion such as brazing. In place of the sine wave member, a triangular wave member may be employed although not shown.

FIG. 8B is a diagram in which a peak portion of a rectangular corrugated plate formed by bending a thin plate of good conductivity (for example, copper) is fixed to the conductive block 41 by a connection layer 46. In this case, each convex side corresponds to one in-space heat exchange member 44, and a plurality of in-space heat exchange members 44 are integrally formed. In the heat exchanger, a closed flow path is formed by the space heat exchange member 44 and the lower surface of the conduction block 41 (not shown) (including the regenerator 30 and the low temperature heat exchange 43). The connection layer 46 is attached by forming the connection layer 46 by adhesion such as brazing.
According to the present embodiment as described above, the structure is inexpensive, the surface area in contact with the working gas can be increased, and the cooling effect can be enhanced.

  Then, the other specific structure of the heat exchange member demonstrated previously is demonstrated. FIG. 9 is a cross-sectional view of the heat exchange member in the space of the elliptical tube of the cold head. This embodiment relates to claim 10. In this embodiment, the in-space heat exchange member 44 is a hollow tubular member. FIG. 9 shows an in-space heat exchange member 44 of an elliptical tubular member obtained by crushing a circular tube of good conductivity (for example, copper). The tops of these in-space heat exchange members 44 are fixed to the conduction block 41 by the connection layer 46, and a large number of them are arranged to form a heat exchanger. In this case, a closed flow path is formed in the pipe of the in-space heat exchange member 44. The connection layer 46 is attached by forming the connection layer 46 by adhesion such as brazing.

  By manufacturing in this way, it is possible to manufacture the single block material at a lower cost than when the in-space heat exchange member 44 is manufactured by processing such as cutting. Further, in machining such as cutting and wire cutting, there is a limit to the thickness and gap of the space heat exchange member 44 that can be processed, and a required surface area may not be ensured. However, according to this method, the thickness and gap of the in-space heat exchanging member 44 can be freely set, and the degree of freedom is increased at the time of designing, and the optimum design is possible.

Then, the structure of the heat exchange member which forms a flow path in a grid | lattice form is demonstrated. FIG. 10 is an explanatory view of the arrangement of the heat exchange members in the space of the cold head of the pulse tube refrigerator of the present embodiment. This embodiment relates to the inventions according to claims 11 and 12. In this embodiment, a plurality of pin-shaped in-space heat exchange members 44 are provided so as to protrude in a substantially vertical direction with respect to the flow path direction on the regenerator 30 side and the pulse tube 50 side. Further, the heat exchanger is formed by arranging a large number of pin-shaped in-space heat exchange members 44 in an equally parallel and parallel arrangement, and the plurality of in-space heat exchange members 44 have lattice-like channels whose channels extend vertically and horizontally. (Well-patterned flow path).
By using a pin shape, it is possible to positively induce vortices and improve the heat transfer coefficient.

Then, the structure of the heat exchange member which forms a flow path in another grid | lattice form is demonstrated. FIG. 11 is a structural diagram of the in-space heat exchange member of the cold head of the pulse tube refrigerator of this embodiment. This embodiment relates to inventions according to claims 11 and 13. In this embodiment, a plurality of pin-shaped in-space heat exchange members 44 are provided so as to protrude in a substantially vertical direction with respect to the flow path direction on the regenerator 30 side and the pulse tube 50 side. Further, the heat exchanger forms a heat exchanger by arranging a large number of pin-shaped space heat exchange members 44 in a staggered arrangement, and the flow paths extend in a staggered manner by the number of space heat exchange members 44. Amida-shaped channel.
In this case as well, by forming a pin shape, it is possible to positively induce vortices and improve the heat transfer coefficient. Moreover, turbulent flow is promoted more than arranging in parallel, and the heat transfer rate can be further improved.

Then, the structure of the heat exchange member which forms a flow path in another grid | lattice form is demonstrated. FIG. 12 is an explanatory view of the arrangement of the heat exchange members in the space of the cold head of the pulse tube refrigerator of this embodiment. This embodiment relates to the inventions according to claims 11 and 14. In this embodiment, a plurality of pin-shaped in-space heat exchange members 44 are provided so as to protrude in a substantially vertical direction with respect to the flow path direction on the regenerator 30 side and the pulse tube 50 side. Furthermore, as shown in FIG. 12, the in-space heat exchanging member 44 of the heat exchanger is radially arranged as a square pin having a large side on the regenerator 30 side and as a square pin having a small side on the pulse tube 50 side. In addition, a large number of pin-shaped heat exchangers 44 in the space are arranged in a constant aperture ratio arrangement, and the flow paths are arranged on the regenerator 30 side and the pulse tube 50 side. ) Is a constant aperture ratio array in which the flow path interval is changed so as to be a constant flow path. A large number of in-space heat exchange members 44 may be arranged on a line connecting the two in-space heat exchange members 44.
As a result, the flow resistances of all the flow paths 45 are equalized by arranging them radially from the side of the pulse tube 50 so as to have the same flow path length in the folded space 42. Becomes constant (= change rate of fluid resistance is constant). Therefore, reducing the pressure loss inside the cold head 40 contributes to improving the overall efficiency of the pulse tube refrigerator 100.

Next, the structure of these pin-shaped heat exchange members will be described. FIG. 13 is a structural diagram of the heat exchange member in the space of the cold head, FIG. 13 (a) is a perspective view of the cylindrical heat exchange member in the space, and FIG. 13 (b) is a view of the heat exchange member in the polygonal column shape. FIG. 13C is a perspective view of a conical space heat exchange member, and FIG. 13D is a perspective view of a polygonal pyramid heat exchange member.
When the upper conductive block 41 and the in-space heat exchange member 44 are cut out and manufactured by cutting the same block material and the like, the in-space heat exchange member 44 is a rectangular parallelepiped due to the balance between the processing limit and cost. It is limited to such a shape. However, when the pin-shaped in-space heat exchange member 44 is directly struck or brazed to the conduction block 41, a large number of pin shapes such as a cylinder, a cone, and a polygonal column can be selected. This makes it possible to promote turbulence, adjust fluid resistance, etc., and expand the options.

  The present invention has been described above. In any of these inventions, a heat exchanger is also installed in the folding space of the cold head to actively exchange heat with the coldest working gas and suppress the expansion of the working gas. Exchanging heat with the coldest working gas at the same time, suppressing the expansion of working gas as much as possible, greatly reducing the thermal loss that has occurred in the cold head, and greatly improving performance Can do.

It is the schematic of the cold head vicinity of the pulse tube refrigerator of the best form for implementing this invention. It is arrangement | positioning explanatory drawing of the heat exchange member in the space of the cold head of the pulse tube refrigerator of the best form for implementing this invention. It is arrangement | positioning explanatory drawing of the heat exchange member in the space of the cold head of the pulse tube refrigerator of the best form for implementing this invention. FIG. 4A is a schematic diagram of a confluent pipe having an equal cross-sectional area, FIG. 4B is a schematic diagram of a straight pipe having an equal cross-sectional area, and FIG. 4C is an equivalent diagram of a confluent pipe. The circuit diagram and FIG. 4D are equivalent circuit diagrams of straight pipes. It is arrangement | positioning explanatory drawing of the heat exchange member in the space of the cold head of the pulse tube refrigerator of the best form for implementing this invention. It is arrangement | positioning explanatory drawing of the heat exchange member in the space of the cold head of the pulse tube refrigerator of the best form for implementing this invention. FIG. 7A is a cross-sectional structural view of a rectangular member, and FIG. 7B is a cross-sectional structural view of a triangular member. FIG. 8A is a structural diagram of an in-space heat exchange member of a cold head, FIG. 8A is a cross-sectional structure diagram of an in-space heat exchange member of a sine wave plate, and FIG. 8B is an in-space heat exchange member of a rectangular wave plate. FIG. It is a cross-section figure of the heat exchange member in the space of the elliptic tube of a cold head. It is arrangement | positioning explanatory drawing of the heat exchange member in the space of the cold head of the pulse tube refrigerator of the best form for implementing this invention. It is arrangement | positioning explanatory drawing of the heat exchange member in the space of the cold head of the pulse tube refrigerator of the best form for implementing this invention. It is arrangement | positioning explanatory drawing of the heat exchange member in the space of the cold head of the pulse tube refrigerator of the best form for implementing this invention. FIG. 13A is a structural diagram of a space heat exchange member of the cold head, FIG. 13A is a perspective view of a columnar space heat exchange member, and FIG. 13B is a perspective view of a polygonal column heat heat exchange member. FIG. 13C is a perspective view of a conical space heat exchange member, and FIG. 13D is a perspective view of a polygonal pyramid heat exchange member. It is a schematic block diagram of the U-shaped return type pulse tube refrigerator of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100: Pulse tube refrigerator 10: Compressor 11: Cylinder 12: Piston 20: After cooler 21: Heat exchanger 22: Radiator 30: Regenerator 40: Cold head 41: Conduction block 42: Turn-back space 43: Low-temperature heat exchange Unit 44: Heat exchange member in space 45: Flow path 46: Connection layer 50: Pulse tube 60: High temperature end 61: High temperature heat exchanger 62: High temperature radiator 70: Phase control unit
71: Inertance tube 72: Buffer tank

Claims (15)

A compressor, a regenerator, a cold head, a pulse tube, and a phase control unit are connected so that the regenerator, the cold head, and the pulse tube are connected in a substantially U shape to form a U-shaped return type flow path. In the U-shaped return type pulse tube refrigerator that generates cold in the cold head by heat exchange with the working gas flowing through the return type flow path,
A heat exchanger formed in the folding space of the cold head;
A flow path divided and formed by the heat exchanger and the cold head so as to communicate between the regenerator side and the pulse tube side;
A pulse tube refrigerator comprising: The pulse tube refrigerator according to claim 1, wherein
In the heat exchanger, a plurality of linear space heat exchange members are provided substantially in parallel with the flow passage directions on the regenerator side and the pulse tube side, and two adjacent space heat exchange members and a cold head are used. A pulse tube refrigerator characterized by being a heat exchanger in which a plurality of substantially linear flow paths are formed. In the pulse tube refrigerator according to claim 2,
The pulse tube refrigerator, wherein the heat exchanger is a heat exchanger in which an in-space heat exchange member is arranged so that the flow path interval is the same on the regenerator side and the pulse tube side. In the pulse tube refrigerator according to claim 2,
The heat exchanger is a heat exchanger in which an in-space heat exchange member is arranged so that a flow path interval is narrow in a long flow path and a flow path interval is wide in a short flow path. Pulse tube refrigerator. The pulse tube refrigerator according to claim 1, wherein
In the heat exchanger, a plurality of linear space heat exchange members are provided radially around the pulse tube side, and a substantially linear flow path is formed radially by two adjacent space heat exchange members and a cold head. A pulse tube refrigerator characterized in that a plurality of heat exchangers are formed. In the pulse tube refrigerator according to claim 5,
The heat exchanger is a heat exchanger in which an in-space heat exchange member is arranged so that the flow path interval is wide on the regenerator side and the flow path interval is narrow on the pulse tube side. Pulse tube refrigerator. In the pulse tube refrigerator according to claim 5,
The heat exchanger is a heat exchanger in which an in-space heat exchange member is arranged so that the gas channel opening ratio (= gas channel cross-sectional area / total cross-sectional area) is constant on the regenerator side and the pulse tube side. A pulse tube refrigerator characterized by being. In the pulse tube refrigerator according to any one of claims 2 to 7,
The pulse heat exchanger according to claim 1, wherein the heat exchange member in the space is a linear member that is a solid body having a rectangular cross section or a triangular cross section. In the pulse tube refrigerator according to any one of claims 2 to 7,
The space heat exchange member is a corrugated member which is a plate having a sine wave shape, a triangular wave shape or a rectangular wave shape in cross section, and a plurality of heat exchange members in the space are integrally formed. In the pulse tube refrigerator according to any one of claims 2 to 7,
The in-space heat exchange member is a hollow tubular member. The pulse tube refrigerator according to claim 1, wherein
The heat exchanger is a heat exchanger provided with a plurality of pin-shaped in-space heat exchange members so as to protrude in a substantially vertical direction with respect to the flow path direction on the regenerator side and the pulse tube side. Pulse tube refrigerator. The pulse tube refrigerator according to claim 11, wherein
The heat exchanger is a pulse tube refrigerator in which a large number of pin-shaped heat exchange members in a space are arranged in a parallel and parallel arrangement to form a lattice flow path. The pulse tube refrigerator according to claim 11, wherein
The heat exchanger is a pulse tube refrigerator characterized in that a large number of pin-shaped heat exchange members in a space are arranged in a staggered arrangement to form a worm-like flow path. The pulse tube refrigerator according to claim 11, wherein
In the heat exchanger, a number of pin-shaped heat exchangers in the space are arranged in a constant aperture ratio arrangement, and the gas channel opening ratio (= gas channel cross-sectional area / total cross-sectional area) on the regenerator side and the pulse tube side. ) Is formed as a constant flow path. In the pulse tube refrigerator according to any one of claims 11 to 14,
The in-space heat exchange member has a cylindrical shape, a polygonal column, a cone, or a pin shape with a polygonal pyramid.

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