JP2600649B2 - Cold generator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a refrigeration generator that can be used in various fields as an alternative device to a cooling device using liquid nitrogen or the like.

[Related Art] In recent advanced industrial technology fields, cooling devices using liquid nitrogen or the like are frequently used. For example, in recent years, GaAs
So-called MOCVD is being put to practical use, which enables the ultimate processing of stacking several layers of GaAlAs and GaAlAs. Thus, in this apparatus, it is necessary to sequentially capture the released Ga and As vapors that have not been deposited on the substrate. That is, the surplus steam must be quickly removed from the heat energy by a buffer disposed around the steam and prevented from jumping out again as steam. Therefore, such a device is provided with a cooling unit in which a buffer of the liquid trap is filled with liquid nitrogen, and a cooling unit configured to be able to sequentially supply liquid nitrogen drawn out from a cylinder or the like into the cooling unit. ing.

[Problems to be Solved by the Invention] However, in a practical device that can be mass-produced, the cooling surface is large and the number of atoms to be trapped is large, so that the consumption of liquid nitrogen is extremely large. for that reason,
There is a problem that the equipment for replenishing the liquid nitrogen becomes large and the running cost is high.

In addition, such a cold generator using liquid nitrogen is used in various fields such as a vacuum insulation chamber of a helium liquefaction apparatus and cooling of an outer shell of a helium supply pipe. There is a problem.

An object of the present invention is to surely solve such a problem with a simple configuration.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a desired method only by circulating a predetermined gas without replenishing a medium which is sequentially consumed such as liquid nitrogen. It is configured so that cold can be obtained. That is,
The cold generation device of the present invention includes gas delivery means for delivering high-pressure argon gas radiated, a plurality of expansion turbines for sequentially adiabatically expanding the argon gas from the gas delivery means and supplying the argon gas to a cold generation end, A plurality of compressors for sequentially compressing the argon gas passing through the cold generation end and returning the compressed gas to the gas delivery unit; and a driving unit for driving the compressor by using the rotational power of the expansion turbine. And

[Operation] With such a configuration, the high-pressure argon gas after heat release sent out from the gas sending means adiabatically expands when passing through each expansion turbine, and its temperature is gradually reduced. Then, at the stage where the temperature has dropped the most, it is supplied to the cold generation end to generate cold. Then, the low-pressure argon gas, which has received heat from an appropriate heat load at the cold generation end, is pressurized by sequentially passing through each compressor driven by using the rotational power of the expansion turbine, and is supplied with gas. Returned to the means. Then, the pressure is further increased as required by this gas supply means, cooled, and sent again to the expansion turbine.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

The cold generating apparatus, argon gas and the gas delivery means 1 for sending A, argon gas A sequentially adiabatic-expanded plurality of inflatable supplied in cold generating end 2 turbine 3 ₁ to 3 ₃ from the gas delivery means 1 When a plurality of compressors ₄₁ to ₃ the argon gas a are sequentially compressed back into the gas delivery means 1 which has passed through the cold generating end 2, the expansion turbine 3 ₁ to 3 ₃
Formed by and a driving means 5 for driving the compressor ₄₁ to ₃ by utilizing the rotational power.

The gas delivery means 1 includes a compressor 6 for compressing the argon gas A, and an after-cooler for exchanging heat between the high-temperature and high-pressure argon gas A discharged from the compressor 6 and water W supplied from a cooling tower (not shown) or a water supply system. The compressor 6 is driven by a motor 8.

Each expansion turbine 3 ₁ to 3 ₃ is of a radial turbine structure formed by accommodating an impeller 91 _to 93 ₃ in the not-shown casing, which is connected pipes in series. Then, so as to supply the argon gas A discharged from the expansion turbine 3 ₃ cold end to the cold generating end 2.

The cold generating end 2 is constituted by, for example, a gas passage provided in a trap of a MOCVD buffer, and the trap can be cooled by the adiabatic expanded argon gas A introduced into the gas passage. I have. Then, and as to introduce the argon gas A that has passed through the cold generating end 2 to the compressor 4 ₃ cold end.

Each compressor 41 _{to 3} is of a radial compressor structure formed by accommodating an impeller 11 ₁ to 11 ₃ in the not-shown casing, which is connected pipes in series, is transmitted via the drive unit 5 wherein it is rotated at high speed by the power from the expansion turbine 3 ₁ to 3 ₃ that. Then, and to return the argon gas A discharged from the compressor 4 ₁ of hot end to the compressor 6 of said gas delivery means 1.

Driving means 5, the impeller 9 ₁ of the expansion turbine 3 ₁ to 3 ₃
To 9 ₃ and the corresponding impeller 11 ₁ to 1 for each compressor 41 _{to 3}
And 1 ₃ is obtained by direct the drive shaft 12 ₁ to 12 _3.

As long as such a configuration, high-pressure argon gas A after the heat radiation delivered from the gas delivery means 1, expands when passing through the respective expansion turbine 3 ₁ to 3 _3. In this case, the specific heat ratio k (constant pressure specific heat Cp / constant volume specific heat Cv) of the argon gas A is 1.6
Gas A itself has a thermal conductivity of 3.88 × 10 ^-5 ca
a ^{l · cm -1 s -1 deg -1} (0 ℃), since it is slightly lower than that of air, the argon gas A by passing through the expansion turbine 3 ₁ to 3 ₃ The adiabatic expansion occurs substantially, and the temperature gradually decreases. Then, the argon gas A is supplied to the cold generation end 2 at the stage when the temperature is the lowest, and is used for cooling the MOCVD trap. Then, argon gas A that has received heat by cooling the trap is boosted by sequentially passes through each compressor 4 _{3-4 1,} is returned to the compressor 6 of the gas delivery means 1. Then, after the pressure is further increased by the compressor 6, it is cooled by the after cooler 7,
Will be circulated is fed toward the expansion turbine 3 ₁ again. In such a cycle, for example, when the outlet pressure of the compressor 6 is 20 ata and the pressure after expansion is 1 ata, the outlet temperature of the after-cooler 7 is 300 K (27 ° C.).
Then, cold of 90.5 K (−182.7 ° C.) can be theoretically generated at the cold generation end 2. FIG. 2 shows a T (temperature) -S (entropy) diagram of this cycle, and points a to i in this drawing correspond to points a to i in FIG. 1, respectively. Of course, the above values assume a complete adiabatic expansion,
Polytropic exponent n when expanded due to a slight decrease in heat insulation efficiency
Even when (= k = 1.667) becomes about 1.5, it is possible to generate a cold of 110.5K (−160.6 ° C.) under the aforementioned pressure ratio. Incidentally, the pressure at each point, a point, of 20 ata (P ₃₎ at point b, 7.4Ata at point c (P _2),
2.7ata (P ₁ ) at point d, 1ata (P ₀ ) at point e and f,
2ata (P ₁ '), 4ata at point h (P _2'), 8ata at point i
(P ₃ ').

As described above, although not capable of generating cold, because this device is so as to sequentially adiabatic expansion by using a plurality of the expansion turbine 3 ₁ to 3 ₃ argon gas A, the cold generating It is possible to achieve substantially the same temperature as when cooling with liquid nitrogen at the end. In other words, the argon gas A is as high as the specific heat ratio is monatomic gas is 1.667, also the heat transmission rate to show a low value compared to helium, and adiabatically expanded by the expansion turbine 3 ₁ to 3 ₃ cold Is easy to generate. Therefore, the liquid nitrogen temperature can be realized without using a heat exchanger or the like. Then, this apparatus only circulates the argon gas A, so that its cold generation end 2
To a desired temperature, there is no need to externally supply a cooling medium such as liquid nitrogen. Moreover, since so as to use the expansion work to be taken when causing adiabatic expansion of the argon gas A to drive the compressor ₄₁ to _3, also power for energy supply from the outside may be of minimal. Therefore, economical operation is possible, and running costs can be significantly reduced. Moreover, this device, since the expansion turbine 3 ₁ to 3 ₃ and the compressor ₄₁ to ₃ and is composed mainly of, not require any large-scale facility to another, simplification and miniaturization of the structure It is easy. Further, since the argon gas A is easily available, the system can be economically constructed and operated.

The expansion turbine and the compressor are not limited to the radial type, and for example, an axial turbine and an axial compressor may be used in combination.

In addition, the application is not limited to cooling of the trap of MOCVD, and can be applied to various devices that require refrigeration. Further, it can be used for a liquid nitrogen temperature panel for a space chamber.

[Effects of the Invention] The present invention has the above-described configuration, and therefore has excellent cold generation that has a simple structure, can be easily miniaturized, can operate economically, and can keep running costs low. An apparatus can be provided.

[Brief description of the drawings]

FIG. 1 is a system explanatory view showing an embodiment of the present invention, and FIG.
The figure is an operation explanatory view of the embodiment. 1 ...... gas delivery means 2 ...... cold generating end 3 ₁ to 3 ₃ ...... expansion turbine ₄₁ to ₃ ...... compressor 5 ...... drive means

Claims (1)

(57) [Claims] 1. A gas delivery means for delivering high-pressure argon gas radiated, a plurality of expansion turbines for sequentially adiabatically expanding the argon gas from the gas delivery means and supplying it to a cold generation end, and the cold generation end. A plurality of compressors that sequentially compress the argon gas that has passed through the compressor and return the compressed gas to the gas delivery unit; and a driving unit that drives the compressor using the rotational power of the expansion turbine. Generator.