JP2645346B2 - Low temperature physical property test equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a test apparatus used for examining physical properties of various substances, particularly physical properties at low temperatures.

[Related Art] In recent years, there has been remarkable competition in the development of superconducting materials. However, in developing superconducting materials, it is essential to examine the low-temperature properties of a newly prepared substance. Conventionally, as a test device for examining the low-temperature physical properties of a substance, the cooling unit of the refrigerator and the cooling room of the refrigerator are arranged adjacent to the cooling unit of the Gifford McMahon refrigerator or its improved refrigerator. Devices housed in vacuum insulated containers are known. In this device, the cold generated in the cooling section of the refrigerator is transmitted to the subject in the accommodation room via gas or solid.

Although this test device is relatively easy to assemble,
Each time a subject in the chamber is replaced with another, the adiabatic vacuum of the equipment must be broken, and the low-temperature atmosphere in the There was an inconvenience that could not be passed on to the test.

Japanese Patent Application No. 62-213329 (Japanese Patent Application Laid-Open No. 1-56151) discloses an apparatus for improving the above-mentioned drawbacks of the low-temperature physical property test apparatus. While inserting the accommodation room, a part of the accommodation room is opened outside the vacuum vessel, and the gaseous refrigerant is circulated between the cooling part of the refrigerator and the subject accommodation room through an appropriate circulation pump and pipe. An apparatus for cooling a subject by causing the subject to cool is described. In this device, a part of the subject storage chamber is opened outside the vacuum container, and the subject can be put in and out of the container through this opening, so that the subject can be replaced without breaking the adiabatic vacuum of the vacuum container. it can.

[Problems to be Solved by the Invention] However, in these conventional low-temperature physical property test devices, the former has a subject accommodation room adjacent to a cooling part of a refrigerator, and the latter has a subject accommodation room. Since the chamber and the cooling unit of the refrigerator are installed in the same vacuum vessel, it is not possible to avoid vibration to the subject accommodation room due to vibration generated when the refrigerator is operated. Vibration of the subject storage chamber can be caused by irradiating the subject with a certain type of light, such as in light experiments, Mossbauer spectroscopy, X-ray diffraction analysis, and electron microscopy. Very inconvenient.

In addition to this, the conventional low-temperature physical property test apparatus has a drawback that a magnet or the like cannot be attached around the subject accommodation room due to structural restrictions related to the installation location of the subject accommodation room.

Therefore, it is an object of the present invention not only to replace the subject without breaking the adiabatic vacuum, but also to prevent the vibration of the refrigerator from being transmitted to the subject accommodating chamber, and further, if necessary, use a magnet or the like. An object of the present invention is to provide a low-temperature physical property test apparatus in which ancillary equipment can be provided around a subject accommodation room.

[Means for Solving the Problems] The low-temperature physical property test apparatus according to the present invention basically includes a cooling unit of a refrigerator and a subject accommodation room in separate vacuum vessels, and a circulating pump. And a conduit for circulating the gaseous refrigerant between the cooling section of the refrigerator and the subject storage chamber.

That is, the low-temperature property test apparatus of the present invention includes: (a) a refrigerator in which a cooling unit adjacent to a heat exchanger for cooling a gaseous refrigerant is located in a first vacuum vessel; A pump located outside the container and for circulating the gaseous refrigerant,
(C) a subject having an inlet and an outlet for a gaseous refrigerant, which is substantially entirely contained in a second vacuum vessel separate from the first vacuum vessel, and whose opening having a lid is located outside the second vacuum vessel; A storage chamber, and (d) a gaseous refrigerant connected to a discharge side of the pump and exchanging gaseous refrigerant discharged from the pump via a heat exchange adjacent to a cooling unit of the refrigerator. A first conduit for the transfer of a gaseous refrigerant to supply to the inlet; (e)
A second conduit for transferring a gaseous refrigerant connected to a refrigerant outlet of the subject storage room and for returning the refrigerant in the storage room to the suction side of the pump.

In the low-temperature property test apparatus of the present invention, the gaseous refrigerant discharged from the pump and flowing through the first conduit is supplied to a heat exchanger adjacent to a cooling unit of the refrigerator. A gas / gas heat exchanger for indirectly exchanging heat with the gaseous refrigerant flowing through the second conduit may be provided in the first vacuum vessel as desired.

[Operation] In the low-temperature physical property test apparatus of the present invention, the installation of the gas / gas heat exchanger described above is not always essential, but in an embodiment in which the gas / gas heat exchanger is installed, the gaseous refrigerant discharged from the circulation pump is connected to a conduit. Through a gas / gas heat exchanger provided in the first vacuum vessel, where it exchanges heat with the gaseous refrigerant returning to the suction side of the circulating pump and then adjacent to the cooling section of the refrigerator And cooled. The cooled gaseous refrigerant is guided to the conduit and is supplied from the first vacuum vessel to the subject accommodation chamber, preferably at the bottom, inserted into the second vacuum vessel to cool the subject in the accommodation chamber. The gaseous refrigerant deprived of heat from the subject is guided from the accommodation chamber into the first vacuum vessel via a conduit, and is returned to the suction side of the circulation pump via the gas / gas heat exchanger.

Therefore, by circulating the gaseous refrigerant as described above while operating the refrigerator, the subject in the accommodation room can be cooled from room temperature to a desired low temperature. Then, after being cooled to the desired temperature, the operation of the refrigerator is stopped,
If the operation of the circulation pump is continued, the gaseous refrigerant gradually absorbs the surrounding heat and is heated, so that the temperature of the cold test object in the accommodation room can be increased. In this case, if a heater is attached to an appropriate portion of the gaseous refrigerant conduit, not only the heating rate can be increased, but also the subject can be heated to room temperature or higher.

The subject accommodation room inserted into the second vacuum container has a part thereof opened to the outside of the second vacuum container, and only the accommodation room is exposed to the atmospheric pressure by opening a lid provided at the opening. By opening and closing the lid, the absorption chamber can be kept airtight. Therefore, the adiabatic vacuum of the second vacuum vessel is not broken when the subject is moved in and out of the accommodation room.

The refrigerator of the present invention includes any refrigerator known in the art,
For example, a single-stage or two-stage helium refrigerator using a Gifford McMahon cycle can be used, and the refrigerator to be used is selected according to a cooling target temperature. Incidentally, the gaseous refrigerant can be cooled to 40K in the single-stage helium refrigerator and to 10K in the two-stage helium refrigerator. Also, if a small helium liquefaction unit is installed, 4K
Can be cooled to a temperature close to As the gaseous refrigerant, a gas that does not solidify at the cooling target temperature is used, and helium gas and nitrogen gas are typically used.

[Embodiment] FIG. 1 shows an embodiment of a low-temperature physical property test apparatus according to the present invention, in which a two-stage helium refrigerator 2 is inserted in a first vacuum vessel 1 and a first cooling thereof. The part 3 and the second cooling part 4 are located in the vacuum container. The first cooling unit 3 and the second cooling unit 4 are respectively provided with a first heat exchanger 5 and a second heat exchanger 6, which are typically composed of cooling coils, adjacent to the first cooling unit 3 and the second cooling unit 4, respectively. Part 4 is radiation heat shield 7
Shielded by. A gas / gas heat exchanger 8 is also provided in the first vacuum vessel, and the vacuum vessel itself is connected to a vacuum pump 10 via a valve 9.

On the other hand, substantially the entirety of the subject accommodation room 12 usually formed of a cylindrical container is inserted into the second vacuum container 11, and the opening of the accommodation room having the lid 13 is positioned outside the vacuum container. The lid 13 has fittings 14 for introducing and discharging the gaseous refrigerant.
And 15 are provided. The second vacuum vessel 11 is the first vacuum vessel 1
In the same manner as described above, it is connected to a vacuum pump 10 'via a valve 9'. Further, instead of providing the refrigerant inlet / outlet of the storage chamber 12 in the lid 13, the refrigerant inlet is placed in the lower part a of the storage chamber, and the refrigerant is taken in and out by reference numerals 22 ', 14', a, b, 15 'and 24 in the figure. It can also be performed by the route shown. In this case, the coolant conduit fitting 1
4 'and 15' may be provided on the side wall of the second vacuum vessel 11.

Conduit 16 having a valve V _1, a conduit 17 which also has a ₂
a, conduit 18 and valve V ₄ with conduit 17b, 17c, the valve V ₃
Are connected to the gaseous refrigerant discharged from the circulation pump 20 provided outside the vacuum vessel, respectively.
The subject accommodation room 12 inserted into the second vacuum vessel 11
A conduit 17a connects the discharge side of the circulation pump to the first heat exchanger 5 via the conduit 16 and the gas / gas heat exchanger 8. The conduit 17b connects the first heat exchanger 5 and the second heat exchanger 6, and the conduit 17c connects the second heat exchanger 6 and the refrigerant outlet pipe fitting 21 of the first vacuum vessel. The conduit 19 joins the refrigerant discharged to the conduit 16 directly to the conduit 17c, and the conduit 18 joins the refrigerant discharged to the conduit 16 to the conduit 17c through the gas / gas heat exchanger 8. . Therefore, by changing the flow ratio of the refrigerant flowing through the conduit 17a and the refrigerant flowing through the conduit 18 or 19, the temperature of the refrigerant flowing through the conduit 17c can be adjusted.

A coolant outlet pipe fitting 21 of the first vacuum vessel 1 and a coolant inlet pipe fitting 14 provided on the lid 13 of the subject housing chamber 12 are connected to a conduit 22.
And the refrigerant discharge pipe fitting 15 of the lid 13 and the refrigerant intake pipe fitting 23 of the first vacuum vessel 1 are connected by a conduit 24. Duplex pipes having an insulated vacuum layer are typically used for the conduits 22 and 24 to minimize heat absorption of the refrigerant passing therethrough. Alternatively, a pipe having a structure in which the conduits 22 and 24 are fixed in a single insulated vacuum tube may be used. Refrigerant intake pipe fitting 23 of first vacuum vessel 1
Is connected to the suction side of the circulation pump 20 via a gas / gas heat exchanger 8 by a conduit 25 having valves V ₅ and V ₆ .

In FIG. 1, reference numeral 26 denotes a helium gas cylinder, and 27, 2
8 is a pressure gauge, 29 is a radiator, 30 is a flow meter, 31 is a refrigerant introduction pipe, 32 is a refrigerant discharge pipe, 33 and 34 are heaters, and 35 is a thermometer.

In the low-temperature physical property test apparatus having the above-described configuration, for example, when measuring the critical temperature of the subject, the subject is allowed to stand still by appropriate means in the accommodation room 12, and the accommodation room is sealed with the lid 13. . Thereafter, while replacing the air in the storage chamber and each conduit with the helium gas supplied from the helium gas cylinder 26, or after the replacement is completed, the vacuum pumps 10, 10 'are operated to operate the first vacuum vessel 1 and the first vacuum vessel. (2) The pressure inside the vacuum vessel 11 is reduced. After the pressure in each vacuum vessel is reduced to, for example, about 5 × 10 ⁻² Torr or less, the refrigerator 2 is started. After the refrigerator reaches the desired refrigeration level, the valves 9, 9 'are normally closed and the operation of the vacuum pumps 10, 10' is stopped.

When the refrigerator 2 is cooled to a desired level, the valves V ₁ and V
_2, V ₅ and opens the V _6, the circulation pump 2 by closing the valves V _3, V ₄
0 operation starts. Helium gas (gaseous refrigerant) discharged from the circulation pump is supplied to the first heat exchanger 5 adjacent to the cooling unit of the refrigerator via the gas / gas heat exchanger 8 and cooled. The refrigerant that has passed through the first heat exchanger 5 is further cooled by passing through the second heat exchanger 6,
The gas is supplied into the subject accommodation room 12 through the conduits 17c and 22 and the refrigerant introduction tube 31, preferably at the bottom thereof. The cold helium gas cools the subject and is returned to the suction side of the circulating pump 19 through the refrigerant outlet 32, conduits 24 and 25. Therefore, by repeatedly circulating the helium gas as a refrigerant between the cooling unit of the refrigerator and the subject storage chamber, the apparatus of the present embodiment provides:
The temperature of the subject in the containment chamber can be reduced to about 15K.

Generally, when measuring the critical temperature of a superconducting material,
There are cases where the critical temperature is measured while gradually increasing the temperature of the subject from extremely low temperatures, and cases where the critical temperature is measured by gradually lowering the temperature of the subject from any temperature. Can also be used. By the way, when the subject is heated from extremely low temperature by the device shown in FIG.
After cooling the subject in the accommodation room 12 to the extremely low temperature in the procedure as described above, the operation of the circulation pump is continued to stop the operation of the refrigerator, and the temperature of the refrigerant supplied to the accommodation room 12 is reduced to the temperature. Total
While monitoring at 35, most simply the heater 33 and / or
Or work 34. Alternatively, while decreasing the opening degree of the valve V ₂ without stopping the operation of the refrigerator, the valve
Increases the opening degree of the V ₃ or V _4, also in a manner that increases the ratio of the refrigerant bypassing the refrigerant-to the heat exchanger through the heat exchanger provided in the cooling portion of the refrigerator, accommodating chamber of the subject temperature Can be gradually raised. Then, by appropriately adjusting the output of the heater and / or the rate of increase of the refrigerant ratio, the rate of temperature increase of the subject can be adjusted. This apparatus is considered to be particularly useful in precision magnetic measurement and the like in which minute vibration is a problem.

FIG. 2 shows another embodiment of the present invention in which a magnet 40 is installed around a second vacuum vessel in which a subject accommodation room is inserted, and shows a first vacuum vessel in which a cooling unit of a refrigerator is inserted. This is abbreviated, and the same parts as those in FIG. 1 are given the same numbers as in FIG. The magnet 40 may be an iron core magnet or a superconducting magnet (this magnet is installed in another container and is usually immersed in liquid helium). The apparatus shown in FIG. 2 is suitable for performing a low-temperature physical property test such as nuclear magnetic resonance (NMR) and electron spin resonance (ESR) on the subject M.

FIG. 3 shows optical spectroscopy and Moessbauer spectroscopy (γ-
1) shows an example of a low-temperature physical property test apparatus used for X-ray spectroscopy, etc., omitting a first vacuum vessel.
In the first vacuum vessel, as in the embodiment shown in FIG.
It goes without saying that the first vacuum vessel having the configuration shown in the figure is used. In this embodiment, as shown in the figure, light introducing windows 51 and 52 are provided on the side walls of the second vacuum vessel 11 and the subject accommodation room 12. For these light introducing windows, quartz glass (light), sapphire (light), aluminum (γ-ray), beryllium (X-ray), or the like can be appropriately used depending on the type of light used. The subject M is installed on the light beam path in the accommodation room 12 via the support pipe 53 and the fixing plate 54.
A copper plate or the like having excellent thermal conductivity can be used for the fixing plate, and a heater and a thermometer can be attached to the fixing plate if necessary. The chamber 55 surrounding the subject M in the accommodation room 12 enters the accommodation room from the refrigerant introduction pipe 31,
This is a protection chamber for preventing the problem that the subject M is displaced by the gas flowing to the refrigerant discharge pipe 32.

The shape of the second vacuum vessel, the position of the light introducing window, the means for fixing the subject, and the like shown in FIG. 3 can be appropriately changed according to the type of light beam used or the purpose of the experiment. As shown in (2), it is also possible to attach a magnet to the second vacuum vessel.

[Effects of the Invention] In the low-temperature physical property test apparatus of the present invention, the vacuum container in which the test object storage chamber is inserted and the vacuum container in which the cooling unit of the refrigerator is inserted are independent of each other. Even if the refrigerator is operated when cooling the subject, the vibration is not transmitted to the subject accommodation room. Further, even when the shape of the second vacuum vessel is limited by NMR, ESR, optical experiments, etc., it can be widely used. Further, since a part of the subject accommodation room inserted into the second vacuum container is opened outside the second vacuum container, the first vacuum container into which the cooling unit of the refrigerator is inserted is of course also provided. Regarding the second vacuum vessel into which the subject accommodation room is inserted, without breaking the adiabatic vacuum,
The subject can be replaced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a low-temperature physical property test apparatus according to one embodiment of the present invention, and FIG. 2 is a cross-sectional view illustrating a device according to another embodiment of the present invention, with a part thereof being omitted. FIG. 3 shows another embodiment of the present invention, in which a part of the apparatus is omitted. 1: first vacuum vessel, 2: refrigerator, 3: first cooling unit, 4: second cooling unit, 5: first heat exchanger, 6: second heat exchanger, 7: radiant heat shield, 8: gas / Gas heat exchanger, 10, 10 ': vacuum pump, 11:
2nd vacuum vessel, 12: subject accommodation room, 13: lid, 20: circulation pump, 26: helium gas cylinder,

Claims (2)

(57) [Claims] 1. A refrigerator in which a cooling unit adjacent to a heat exchanger for cooling a gaseous refrigerant is located in a first vacuum vessel; and (b) a refrigerator is located outside the first vacuum vessel. A pump for circulating the gaseous refrigerant, and (c) a lecture section having a lid, which is substantially entirely contained in a second vacuum container separate from the first vacuum container and which has an inlet and an outlet for the gaseous refrigerant. And (d) connected to a discharge side of the pump, and exchanges gaseous refrigerant discharged from the pump with heat exchange adjacent to a cooling unit of the refrigerator. A first conduit for transferring a gaseous refrigerant for supplying to a refrigerant inlet of the subject storage chamber, and (e) connected to a refrigerant outlet of the test subject storage chamber to pump the refrigerant in the storage chamber through the pump. Low-temperature physical property test device, comprising a second conduit for transferring a gaseous refrigerant for returning to the suction side of Place. 2. A gaseous refrigerant discharged from said pump and flowing through a first conduit before being supplied to a heat exchanger adjacent to a cooling part of a refrigerator. 2. The low-temperature physical property test apparatus according to claim 1, further comprising a heat exchanger for indirectly exchanging heat with the refrigerant in the first vacuum vessel.