JPH02131143A - Low temperature physical property testing device - Google Patents

Abstract

PURPOSE:To ensure that a test sample is easily replaced by accommodating a refrigerating section and a storage chamber for a test sample in separate vacuum containers respectively after refrigeration and arranging a duct between these containers. CONSTITUTION:A test sample is placed in a standstill condition in a storage chamber 12 and the storage chamber is tightly closed with a cover 13. Next the air in the storage chamber and each duct is replaced with helium gas supplied from a helium gas container 26, and vacuum containers 1, 11 are evacuated. After a refrigerator 2 is cooled to a desired level, valves V1, V2, V3, V4 are opened, and the valves V3, V4 are closed to start a circulation pump 19. The helium gas discharged from the circulation pump is suppled to to a heat exchanger 5 adjacent to the refrigeration section of the refrigerator through a gas/gas heat exchanger 8 and then is cooled. After this, the gas is further cooled, passing through the second heat exchanger 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a testing device used to examine the physical properties of various substances, particularly physical properties at low temperatures.

[Prior Art] Competition in the development of superconducting materials has been remarkable in recent years, but in developing superconducting materials, it is essential to investigate the low-temperature physical properties of newly prepared substances. Conventionally, test equipment for investigating the low-temperature physical properties of substances has been constructed by placing a subject accommodation chamber adjacent to the cooling section of a Gifford-McMahon refrigerator or an improved version thereof, and connecting the cooling section of the refrigerator and the subject accommodation chamber. A device housed in a vacuum insulated container is known. In this device, the cold generated in the cooling section of the refrigerator is transmitted to the subject in the containment chamber via gas or solid.

Although this test device is relatively easy to assemble, each time the test subject in the containment chamber is replaced with another, the device's adiabatic vacuum must be broken, and therefore the previous test There was an inconvenience that the low-temperature atmosphere inside the containment chamber, which had been achieved in the previous test, could not be carried over to the next test.

Japanese Patent Application No. 62-213329 proposes an apparatus that improves the shortcomings of the low-temperature physical property testing apparatus as described above, in which the cooling part of the refrigerator and the test subject storage chamber are inserted into a single vacuum container. The subject is cooled by opening a part of the chamber to the outside of the vacuum container and circulating a gaseous refrigerant between the cooling part of the refrigerator and the subject accommodation chamber via a suitable circulation pump and pipes. The equipment is described. With this device,
A part of the test subject storage chamber is opened to the outside of the vacuum container, and the test object can be taken in and out of the container through this opening, so that the test object can be replaced without breaking the adiabatic vacuum of the vacuum container.

[Problems to be Solved by the Invention] However, among these conventional low-temperature physical property testing devices, the former has a subject storage chamber adjacent to the cooling section of the refrigerator, and the latter has a Since the cooling part of the chamber and the refrigerator are installed in the same vacuum container, it is impossible to avoid vibrations generated when the refrigerator is operated from extending to the subject accommodation chamber.

Vibrations in the test subject storage chamber are used when a certain type of light is irradiated onto the test subject to analyze its physical properties, such as in optical experiments, Mössbauer spectroscopy, X-ray diffraction analysis, electron microscopy, etc. , extremely inconvenient.

In addition to this, conventional low temperature physical property testing equipment.

Due to structural constraints related to the location of the test subject storage room,
There was also the drawback that magnets could not be attached around the subject containment chamber.

Therefore, it is an object of the present invention to not only be able to exchange a test subject without destroying the adiabatic vacuum, but also to prevent the vibrations of the refrigerator from being transmitted to the test containment chamber, and to use magnets or other devices as necessary. An object of the present invention is to provide a low-temperature physical property testing device in which ancillary equipment can be provided around a test subject accommodation chamber.

[Means for Solving the Problems] Basically, the low-temperature physical property testing device according to the present invention houses the cooling part of the refrigerator and the test subject storage chamber in separate vacuum containers, and connects them via a circulation pump. The structure includes a conduit for circulating a gaseous refrigerant between the cooling section of the refrigerator and the subject accommodation chamber.

That is, the low-temperature physical property testing apparatus of the present invention includes (a) a refrigerator in which a cooling section adjacent to a heat exchanger for cooling a gaseous refrigerant is located in a first vacuum container; (b) a first vacuum container; a pump located outside the vessel for circulating the gaseous refrigerant;
C) A test subject housing that is substantially entirely contained within a second vacuum container separate from the first vacuum container, including an inlet and an outlet for a gaseous refrigerant, and an opening with a lid located outside the second vacuum container. (d) connected to the discharge side of the pump, the gaseous refrigerant discharged from the pump is passed through a heat exchanger adjacent to the cooling section of the refrigerator to the refrigerant inlet of the subject accommodation chamber; (8) a first conduit for transferring a gaseous refrigerant for supplying the refrigerant to the subject storage chamber; and (8) a first conduit for transferring the gaseous refrigerant for returning the refrigerant in the storage chamber to the suction side of the pump, which is connected to the refrigerant outlet of the subject storage chamber. and a second conduit.

In the low-temperature physical property testing apparatus of the present invention, the gaseous refrigerant discharged from the pump and flowing through the first conduit is
Optionally, a gas/gas heat exchanger for indirectly exchanging heat with the gaseous refrigerant flowing through the second conduit prior to supplying the heat exchanger adjacent to the cooling section of the refrigerator. It can be provided within the first vacuum container.

[Function] Although the installation of the gas/gas heat exchanger described above is not necessarily essential in the low-temperature physical property testing apparatus of the present invention, in an embodiment in which this is installed, the gaseous refrigerant discharged from the circulation pump is After heat exchange with the gaseous refrigerant, which is supplied to the gas/gas heat exchanger provided in the first vacuum vessel through which the gaseous refrigerant returns to the suction side of the circulation pump, the heat exchanger adjacent to the cooling section of the refrigerator It is introduced into a container and cooled. The cooled gaseous refrigerant is guided by a conduit and is supplied from the first vacuum vessel to the bottom of the subject accommodation chamber, which is inserted into the second vacuum vessel, to cool the subject within the accommodation chamber. The gaseous refrigerant, which has taken heat from the subject, is led from the storage chamber into the first vacuum vessel via a conduit and 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 housing chamber can be cooled from room temperature to a desired low temperature. Once cooled to the desired temperature, if the refrigerator is stopped and the circulation pump continues to operate, the gaseous refrigerant gradually absorbs the surrounding heat and becomes warmer inside the storage room. The temperature of a cold subject can be increased. In this case, by attaching a heater to an appropriate location in the gaseous refrigerant conduit, it is possible not only to increase the heating rate but also to heat the subject above room temperature.

A part of the subject storage chamber inserted into the second vacuum container opens to the outside of the second vacuum container, and by opening the lid installed in the opening, only the storage chamber is brought under atmospheric pressure. By opening the lid and closing the lid, the storage chamber can be kept airtight. Therefore, the adiabatic vacuum of the second vacuum container is not destroyed when the subject is taken into or out of the storage chamber.

Any refrigerator known in the art can be used as the refrigerator of the present invention, for example, a single-stage or two-stage helium refrigerator using the Gifford-McMahon cycle, and depending on the cooling target temperature, The refrigerator to be used is selected. By the way,
A single-stage helium refrigerator can cool the gaseous refrigerant to 40K, and a two-stage helium refrigerator can cool the gaseous refrigerant to 10K. In addition, if a small helium liquefaction device is installed, 4
It can be cooled to temperatures close to K. As the gaseous refrigerant, a gas that does not solidify at the cooling target temperature is used, typically helium gas or nitrogen gas.

[Embodiment] FIG. 1 shows an embodiment of the low-temperature physical property testing apparatus according to the present invention, in which a two-stage helium refrigerator 2 is inserted into the first vacuum vessel 1, and the first Cooling section 3 and second cooling section 4
is placed in a vacuum vessel. A first heat exchanger 5 and a second heat exchanger 6, which are typically composed of cooling coils, are installed adjacent to the first cooling section 3 and the second cooling section 4, respectively, and the second cooling section The portion 4 is shielded by a radiant heat shield 7. Also provided within the first vacuum vessel is a gas/gas heat exchanger 8 , which itself is connected via a valve 9 to a vacuum pump 10 .

On the other hand, almost the entirety of a subject storage chamber 12, which is usually a cylindrical container, is inserted into the second vacuum container 11.

The opening of the receiving chamber with the lid 13 is located outside the vacuum vessel. The lid 13 is provided with fittings 14 and 15 for an inlet pipe and a discharge pipe for the gaseous refrigerant. Like the first vacuum container 1, the second vacuum container 11 is connected to a vacuum pump 10' via a valve 9'. In addition, instead of providing the refrigerant inlet and 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 inserted and removed with reference numeral 22' in the figure.
14″, i.

It is also possible to use the routes shown at 15' and 24.

In this case, the fittings 14' and 15' of the refrigerant conduits are
It may also be provided on the side wall of the vacuum container 11.

Conduit 16 having valve V □, conduit 17a, conduit 17b, 17c also having v2, conduit 18 having valve v3, and conduit 19 having valve ■ are each discharged by a circulation pump 20 provided outside the vacuum container. The conduit 17a is a conduit for supplying a gaseous refrigerant through the first vacuum container 1 to the subject accommodation chamber 12 inserted in the second vacuum container 11, and the conduit 17a is connected to the discharge side of the circulation pump. It is connected to the first heat exchanger 5 via a conduit 16 and a 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 extraction pipe fitting 21 of the first vacuum vessel. Further, the conduit 19 allows the refrigerant discharged to the conduit 16 to directly join the conduit 17c, and the conduit 18 allows the refrigerant discharged to the conduit 16 to pass through the gas/gas heat exchanger 8 and join the conduit 17c. . Therefore, the refrigerant flowing through the conduit 17a and the conduit 18
Alternatively, by changing the flow rate ratio of the refrigerant flowing through the conduit 17c, the temperature of the refrigerant flowing through the conduit 17c can be adjusted.

The refrigerant outlet pipe fitting 21 of the first vacuum container 1 and the refrigerant introduction pipe fitting 14 provided on the lid 13 of the subject accommodation chamber 12 are connected by a conduit 22, and the refrigerant discharge pipe fitting 15 of the lid 13 and 1 is connected to the refrigerant intake pipe fitting 23 of the vacuum vessel 1 by a conduit 24.

The conduits 22 and 24 are typically double pipes with an insulating vacuum layer to minimize heat absorption of the refrigerant passing therethrough. It is also possible to use a pipe structure in which the conduits 22 and 24 are fixed within a single insulated vacuum tube. The refrigerant intake pipe fitting 23 of the first vacuum container 1 is
Valve V,,V.

It is connected to the suction side of the circulation pump 20 via the gas/gas heat exchanger 8 by a conduit 25 having a .

In addition, in Fig. 1, 26 is a helium gas cylinder, and 27 is a helium gas cylinder.
．． 28 is a pressure gauge, 29 is a radiator, 30 is a flow meter, 31 is a refrigerant inlet pipe, 32 is a refrigerant discharge pipe, 33, 34 is a heater, and 35 is a thermometer.

In the low-temperature physical property testing apparatus configured as described above, for example, when measuring the critical temperature of a subject, the subject is left still in the holding chamber 12 by an appropriate means, and the holding chamber is sealed with the lid 13. . Thereafter, while replacing the air in the storage chamber and each conduit with helium gas supplied from the helium gas cylinder 26, or after the replacement is completed, the vacuum pump 10.10
' is operated to reduce the pressure inside the first vacuum container 1 and the second vacuum container 11. For example, the pressure inside each vacuum container is 5 x 1
After reducing the pressure to about 0-” Torr or less, start the refrigerator 2. After the refrigerator reaches the desired freezing level,
Normally, the valves 9 and 9' are closed to stop the operation of the vacuum pumps 10 and 10'.

Once the refrigerator 2 has been cooled to the desired level, valve V1.
V2. V and V are opened, valves V and V are closed, and operation of the circulation pump 19 is started. Helium gas (gaseous refrigerant) discharged from the circulation pump is supplied to the first heat exchanger 5 adjacent to the cooling section of the refrigerator via the gas/gas heat exchanger 8 and is cooled. The refrigerant that has passed through the first heat exchanger 5 is further cooled by passing through the second heat exchanger 6, and then passes through the conduits 17c and 22 and the refrigerant introduction pipe 31 into the subject accommodation chamber 12. Preferably it is fed at the bottom. The cold helium gas cools the subject and is returned to the suction side of the circulation pump 19 through the coolant discharge pipe 32, conduits 24 and 25. Therefore, by repeatedly circulating helium gas, which is a refrigerant, between the cooling part of the refrigerator and the subject accommodation chamber, the apparatus of this embodiment can reduce the temperature of the subject in the accommodation chamber to approximately 15K. can.

Generally, when measuring the critical temperature of superconducting materials, there are two methods: one is to measure the critical temperature while gradually increasing the temperature of the test object from an extremely low temperature, and the other is to measure the critical temperature by gradually lowering the temperature of the test object from an arbitrary temperature. However, the device of the present invention can be used for any of them. By the way, when raising the temperature of a test subject from a cryogenic temperature using the device shown in Figure 1, the circulation pump continues to operate after cooling the test subject in the containment chamber 12 to a cryogenic temperature using the procedure described above. The simplest method is to stop the operation of the refrigerator and monitor the temperature of the refrigerant supplied to the storage chamber 12 with the thermometer 35.
and/or work 34. Alternatively, the opening degree of valve v2 is decreased and the opening degree of valve v3 or v4 is increased without stopping the operation of the refrigerator, and the refrigerant pair is passed through a heat exchanger provided in the cooling section of the refrigerator. Techniques that increase the proportion of refrigerant that bypasses the heat exchanger can also gradually increase the temperature of the subject within the containment chamber. By appropriately adjusting the output of the heater and/or the rate of increase in the refrigerant ratio, the rate of increase in temperature of the subject can be adjusted. This device is considered to be particularly useful in precision magnetic measurements where minute vibrations are a problem.

FIG. 2 shows another embodiment of the present invention in which a magnet 40 is installed around a second vacuum container in which a subject accommodation chamber is inserted, and a first vacuum container in which a cooling section of a refrigerator is inserted. This is omitted and the same parts as in FIG. 1 are given the same numbers as in FIG. 1.

The magnet 40 can be either an iron core magnet or a superconducting magnet (this magnet is placed in a separate container and is typically immersed in liquid helium).

The apparatus shown in FIG.
It is suitable for conducting low-temperature physical property tests such as MR) and electron spin resonance (ESR).

Figure 3 shows optical spectroscopy, Mössbauer spectroscopy (γ-ray)
, an embodiment of a low-temperature physical property testing device used for X-ray spectroscopic analysis, etc., is shown with the first vacuum vessel omitted. 1st
It goes without saying that the first vacuum container having the configuration shown in FIG. 1 is used as the vacuum container, similar to the embodiment shown in FIG. 2.

In this embodiment, as illustrated, light beam introducing windows 51 and 52 are provided on the side walls of the second vacuum container 11 and the subject storage chamber 12. For these light beam introduction windows, quartz glass (light), sapphire (light), aluminum (γ-rays), beryllium (X-rays), etc. can be used as appropriate depending on the type of light beams used.

The subject M is placed on the light path inside the storage chamber 12 via the support pipe 53 and the fixing plate 54 . A copper plate or the like with excellent thermal conductivity can be used as the fixing plate, and a heater and a thermometer can be attached to this plate if necessary. The chamber 55 surrounding the subject M in the accommodation chamber 12 is a protective chamber that prevents the subject M from being displaced by gas that enters the accommodation chamber from the refrigerant introduction pipe 31 and heads toward the refrigerant discharge pipe 32. It is.

The shape of the second vacuum container shown in FIG. 3, the position of the light beam introduction window,
The means for fixing the subject can be changed as appropriate depending on the type of light beam used or the purpose of the experiment, and it is also possible to attach a magnet to the second vacuum container as shown in Figure 2. be.

[Effects of the Invention] In the low-temperature physical property testing device of the present invention, the vacuum container in which the subject storage chamber is inserted and the vacuum container in which the cooling section of the refrigerator is inserted are independent of each other. Even if the refrigerator is operated to cool a subject, its vibrations will not be transmitted to the subject accommodation chamber. Further, even if there are restrictions on the shape of the second vacuum container in NMR, ESR1 optical experiments, etc., it can be widely used. Furthermore, since the test subject accommodation chamber inserted into the second vacuum container has its negative part open to the outside of the second vacuum container, the first part into which the cooling part of the refrigerator is inserted is
The subject can be exchanged not only in the vacuum container but also in the second vacuum container in which the subject storage chamber is inserted without destroying its adiabatic vacuum.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a low-temperature physical property = 16- test apparatus which is an embodiment of the present invention, and Fig. 2 shows an apparatus which is another embodiment of the present invention, with some parts omitted. FIG. 3 is a sectional view showing an apparatus according to still another embodiment of the present invention, with some parts thereof omitted. 1: first vacuum container, 2: refrigerator, 3: first cooling section,
4: Second cooling section, 5: First heat exchanger, 6: Second heat exchanger, 7: Radiant heat shield, 8: Gas/gas heat exchanger, io, io'' vacuum pump, 11: Second vacuum vessel , 12: Subject storage chamber, 13: Lid, 20: Circulation pump, 26: Helium gas cylinder, Patent applicant: 1st grade, 1st grade picture, 1st picture, 3rd picture: Director General of the Patent Office, Yoshi 1) Display of Moon Take-don incident, Showa era Patent Application No. 283480 of 1963 Name of the invention Relationship with the case of person who makes amendments to low-temperature physical property testing equipment Patent applicant 1st grade, 9-53 Hiyoshidai 1-cho, Takatsuki City, Osaka Prefecture Kei Kei (1 other person)

Claims (1)

[Claims] 1. (a) A refrigerator in which a cooling part adjacent to a heat exchanger for cooling a gaseous refrigerant is located inside a first vacuum vessel; (b) outside the first vacuum vessel. (c) a second vacuum container separate from the first vacuum container, comprising a gaseous refrigerant inlet and an outlet, and having a lid; (d) connected to the discharge side of the pump, the gaseous refrigerant discharged from the pump is connected to the chamber adjacent to the cooling section of the refrigerator; (e) a first conduit for transferring a gaseous refrigerant for supplying the refrigerant to the refrigerant inlet of the subject accommodation chamber via heat exchange; a second conduit for transporting gaseous refrigerant to return the gaseous refrigerant to the suction side of the pump. 2. Before the gaseous refrigerant discharged from the pump and flowing through the first conduit is supplied to the heat exchanger adjacent to the cooling section of the refrigerator, the gaseous refrigerant flowing through the second conduit is indirectly connected to the gaseous refrigerant flowing through the second conduit. 2. The low-temperature physical property testing apparatus according to claim 1, further comprising a heat exchanger provided in said first vacuum container for performing heat exchange.