Ultralow temperature refrigerator, refrigerating system, and vacuum apparatus

Abstract

An ultralow temperature refrigerator (R) using a mixed refrigerant containing a plurality of kinds of refrigerants having different boiling points. The refrigerator comprises a main refrigerant circuit (38) provided with a criocoil and a capillary tube (29) and a sub-refrigerant circuit (39) the upstream end of which is branched and connected to the upstream end of the main refrigerant circuit (38) and which is provided with a capillary tube (28). In order to ensure the flow of the liquid refrigerant for a supercooler (31) and to enhance the cooling eficiiency of the criocoil (32), the height of the sub-refrigerant circuit (39) is less than the height of the main refrigerant circuit (38). The flow of the refrigerant in a gas-liquid mixed state discharged from the primary side (31a) of the supercooler (31) and flowing into the sub-refrigerant circuit (39) is greater than the flow into the main refrigerant circuit (38), so that the flow of the liquid refrigerant into the sub-refrigerant circuit (39) is increased more than the flow into the main refrigerant circuit (38).

Description

technical field [0001] The present invention relates to an ultra-low temperature freezing device, a freezing system and a vacuum device for generating ultra-low temperature cooling capacity. Background technique [0002] So far, as a refrigeration system for generating ultra-low temperature below -100°C, as shown in Patent Documents 1, 2, and 3, a non-azeotropic mixed refrigerant formed by mixing a plurality of refrigerants with different boiling point temperatures is enclosed in a refrigerant circuit. Methods for ultra-low temperature freezers are known. This kind of ultra-low temperature freezing device, such as the moisture installed in the vacuum tank of the vacuum film forming device for manufacturing substrates (wafers), etc., is removed by freezing to improve the vacuum level. [0003] The refrigerant circuit of the refrigeration system basically consists of compressors, condensers, multiple stages of gas-liquid separators, multiple stages of gas-liquid separators, m...

AI Technical Summary

Problems solved by technology

For this reason, the flow rates of the refrigerant flowing to the main cooler and the subcooler are set to be equal to each other as described above. However, if the amount of liquid refrigerant flowing to the secondary side of the subcooler is small, the flow rate of the gas refrigerant on the primary side will be reduced. Insufficient cooling, which leads to a decrease in the flow rate of liquid refrigerant liquefied by the subcooler and a reduction in the cooling efficiency of the main cooler

As a result, the load of the cooling object cooled by the main cooler fluctuates, or the cooling object whose load fluctuates cannot be cooled stably, or the cooling required to cool the cooling object from normal temperature to ultra-low temperature by the main cooler The problem of extended time

[0012] (2) Next, stop the normal operation of the refrigerating device, and supply the blown gas from the compressor to the cooler through the defrosting circuit to defrost the cooler. If the oiler removes the refrigeration oil, the refrigeration oil will flow into the defrosting circuit, supply it to the cooler in the ultra-low temperature state, and freeze in the refrigerator.

[0013] (3) Again, if the refrigerating machine oil etc. are supplied to the cooler and solidified in the cooler, then even if the refrigerating machine oil passes through the cooler when the temperature of the cooler is raised, the refrigerating machine oil flowing out of the cooler is equivalent to the ultra-low temperature state It is supplied to the heat exchanger, and the refrigerating machine oil will also solidify in the heat exchanger. It takes time to eliminate the solidification of the refrigerating machine oil, etc., resulting in the problem that the defrosting operation time is prolonged.

However, in this method, a pressure loss occurs due to the flow resistance of the mixed refrigerant, and there is another problem that the cooling efficiency is lowered.

[0015] (4) Also, in recent years, in order to improve the cooling capacity of refrigeration equipment, low-boiling refrigerants that are kept in a gaseous state during operation and shutdown have been widely used. Therefore, the problem of insufficient capacity of the buffer tank has arisen.

[0019] In this way, it is difficult to cool the cooler to the ultra-low temperature level in a short time in the conventional pressure reducer circuit configuration

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