JPH03152381A - Very low temperature cooling device - Google Patents

Abstract

PURPOSE:To improve vibration insulation by filling a space between a cooler and a Dewar with a vibration damping member having a vibration damping effect. CONSTITUTION:A space 7a between a cold finger 4 and a cylinder wall 2 is filled therein with a vibration damping member 10, the thin cylinder wall 2 being supported by said two members. The wall of the cold finger 4 has its thickness durable against internal pressure of several tens atoms, so that the frequency of vibration of the normal mode of the cylinder wall 2 supported by the vibration damping member 10 and the cold finger 4 is very high and is unlikely to resonate for vibration caused by operation of a cooler. Further, the vibration damping member has a greater vibration damping characteristic in itself and hence the vibration is further suppressed. Hereby, vibration isolation is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cryogenic cooling device for cooling various elements such as infrared elements.

[Prior Art] FIG. 6 is a partially cutaway side view showing the interior of a conventional cryogenic cooling device disclosed in, for example, US Pat. No. 4,802,345. In the figure, (1) is Dewar,
It is constructed by airtightly joining a cylindrical wall (2) made of thin metal or glass and a metal cap (3). Further, a cold finger (4) is inserted concentrically into the inside of the dewar (1), and the cold finger (4) is connected to a compression pipe (5) and a compression pipe (5) that communicate with each other via a connecting pipe (5). Together with the machine (not shown), they collectively constitute a gas cycle cooler (6), for example a Stirling cycle cooler. On the other hand, in the space (7) between the cold finger (4) and the dewar (1), a low boiling point gas (e.g. , neon gas, etc.), and in this way, the operation of the cooler (6) causes the cold finger (4) to
The cold heat generated in the low temperature part (4a) at the tip of the dewar cools the cap (3) at the tip of the dewar (1) due to the heat conduction of this gas, and further cools the cap (3) at the tip of the dewar (1). It is configured to cool the object (9) to be cooled.

Next, the operation of the conventional cryogenic cooling device described above will be explained. When energy is input from the outside to the cooler (6), the cold fingers (4) forming a part of the cooler (6)
) Cold heat is generated in the low temperature part (4a) at the tip. on the other hand,
In the space (7) between the cold finger (4) and the dewar (1), a low boiling point gas (for example, neon gas, etc.) that maintains a gas state even at the cooling temperature of this cryogenic cooling device is used for heat transfer. Since it is enclosed as a means (8), the cold heat generated in the low temperature part (4a) of the cold finger (4) is transmitted to the cap (3) by thermal conduction of this gas,
In this way, the cab (3) and the object to be cooled (9) provided thereon are cooled by the cooling 1 m (6).

Although the explanation of the structure and operation of the gas cycle cooler used in this cooling device has been omitted here, the structure of various gas cycle coolers and the principle of generating cold heat can be found in the literature (rCryoco.

1ersJ (G, Walker, PlenumPr
ess, New York, 19
83))! This is explained in detail.

[Problems to be Solved by the Invention] Since the conventional cryogenic cooling device is configured as described above, in order to reduce the loss of cold energy due to heat conduction through the cylindrical wall (2- ) is desired to be as thin as possible. On the other hand, when the thickness of the cylindrical wall (2) is reduced, the natural frequency of the cylindrical wall (2) decreases, so the cylindrical wall (2) resonates due to external vibrations (such as those caused by the operation of the cooler). In some cases, the cylindrical wall (2
) was destroyed. In addition, the cylindrical wall (2
) and the cold finger (4) is also filled with gas as a heat transfer medium, so the cold heat of the low temperature part (4a) is dissipated through this gap, reducing the efficiency of the cooling device. There was also the problem of allowing

This invention was made to solve the above-mentioned problems, and an object thereof is to obtain a cryogenic cooling device with excellent vibration resistance.

[Means for Solving the Problems] A cryogenic cooling device according to the present invention is one in which a vibration damping member having a vibration damping effect is filled in a space between a cooling machine and a dewar.

[Function] In the cryogenic cooling device according to the present invention, the damping member filled in the space between the cold finger and the cylindrical wall cooperates with the cold finger to support the thin cylindrical wall, so that the vibration of the cylindrical wall is reduced. Prevent resonance.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
In the figure, (10) is a latent vibration member made of foamed resin, and is mounted so as to fill the interspace (7a) between the cold finger (4) and the cylindrical wall (2).

Next, the operation will be explained.

The space between the cold finger (4) and the cylindrical wall (2) (
Since the damping member (10) is filled in 7a), the thin cylindrical wall (2) is supported by the damping member (10) and the cold fingers (4). On the other hand, since the wall of the cold finger (4) is thick enough to withstand the internal pressure of several tens of atmospheres, the cylindrical wall supported by the vibration damping member (10) and the cold finger (4) The natural frequency of (2) is very high, and external vibrations (such as vibrations caused by cooling machine operation)
It becomes difficult to resonate with. Further, since the vibration damping member itself has a large vibration damping characteristic, negative layer vibration is suppressed.

Furthermore, by filling the gap (7a) between the cylindrical wall (2) and the cold finger (4) with a vibration damping member (lO) made of foamed resin, the thermal conductivity in this space (7a) is reduced. The cold heat of the low temperature section (4a) is prevented from dissipating through this gap, and the efficiency of the cooling device is improved.

In addition, in the above embodiment, the entire gap (7a) between the cylindrical wall (2) and the cold finger (4) is covered with the damping member (lO
), but the examples shown in Figures 2 and 3
As shown in the figure, only a part of the gap (7a) may be filled, and the same effect as in the above embodiment can be obtained.

Further, in the above embodiment, the dewar (1) is replaced by the cylindrical wall (2).
) and cap (3), but as shown in Fig. 4, an outer wall (1
1) and the space (12) between the outer wall (11) and the space (12) is maintained in a vacuum, the same effect as in the above embodiment can be obtained.

Furthermore, in the above embodiment, the heat transfer means 8) between the low temperature part (4a) of the cold finger (4) and the dewar (1) is
Although we have shown an example using heat conduction of a non-condensable gas, as shown in Figure 5, it can also be applied to other methods such as bundles of copper foil etc. as the heat transfer means (8). However, the same effect as in the above embodiment can be obtained.

Furthermore, in the above embodiments, foamed resin was used as the damping member (10), but damping materials other than foamed resin, such as rubber, may be used.

[Effects of the Invention] As described above, according to the present invention, a vibration damping member having a vibration damping effect is filled in the space between the cooler and the dewar, so that a cryogenic cooling device with excellent vibration resistance can be achieved. There is an effect that can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side view showing the inside of a cryogenic cooling device according to one embodiment of the present invention, and FIGS. 2 to 5 all show cryogenic cooling devices according to other embodiments of the present invention. FIG. 6 is a side view showing the inside with a part cut away, and FIG. 6 is a side view showing the inside of a conventional cryogenic cooling device with a part cut away. (1)...Dewar, (4)...Cold finger (4a)...Low temperature section, (6)...Cooler, (7
)(7a)...Space, (8)...Heat transfer means, (9)
. . . Cooled object, (10) . . . Vibration damping member In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A cooler, a dewar provided surrounding a low-temperature part of the cooler, and a heat transfer means provided between the dewar and the cooler, wherein a part of the wall of the dewar is heated by the heat transfer means. In a cryogenic cooling device configured such that an object to be cooled attached to the outer wall of the dewar is cooled by thermally contacting the low temperature part, vibration is generated in the space between the cooler and the dewar. A cryogenic cooling device characterized by being filled with a vibration damping member having a damping effect.