JPH04256403A - Method for degassing boiling cooler - Google Patents

Abstract

PURPOSE:To excellently liberate a noncondensable gas without damaging a boiling cooler even when an aq. ethylene glycol soln. 15 is used as the cooling medium. CONSTITUTION:An aq. ethylene glycol soln. 15 is kept below its freezing temp. for a specified time and converted into sherbet, the vessel of the boiling cooler is evacuated, and the noncondensable gas is liberated.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to a boiling cooling device for degassing non-condensable gas, for example, from a boiling cooling device for cooling a thyristor element of a chopper device mounted on a subway car. It's about how you feel.

0002

[Prior Art] Figure 2 shows, for example, Mitsubishi Electric Technical Report Vol. 48, 2.
FIG. 2 is a configuration diagram showing a conventional boiling cooling type thyristor device similar to that shown in the above issue. In the figure, 1 is an evaporator, 2 is a thyristor element housed in the evaporator 1, and 3 is a thyristor element housed in the evaporator 1.
is a fin housed in the evaporator 1 and connected to the thyristor element 2, 4 is a terminal of the thyristor element 2 drawn out from the evaporator 1, and 5 is a fin installed in the evaporator 1 to cool the thyristor element 2. The contained fluorocarbon liquid, 6 is a condenser connected to the evaporator 1 via a steam pipe 7 and a liquid return pipe 8, 9 is a deaeration pipe connected to the steam pipe 7, and 10 is a deaeration pipe. This is a valve provided in the pipe 9.

Next, the operation will be explained. The heat generated in the thyristor element 2 is radiated to the fluorocarbon liquid 5 through the fins 3 that are pressed against the cooling surface of the thyristor element 2. As a result, the fluorocarbon liquid 5 is boiled, and fluorocarbon vapor 5a is generated within the evaporator 1. The generated fluorocarbon vapor 5a is transferred to the steam pipe 7
It passes through the condenser 6, where it is condensed and returned to the fluorocarbon liquid 5. The condensed fluorocarbon liquid 5 is transferred to a liquid return pipe 8
Then it returns to the evaporator 1 again. By repeating such operations, the thyristor element 2 continues to be cooled.

Next, a conventional deaeration method will be explained. Conventionally, non-condensable gas dissolved in the fluorocarbon liquid 5 is degassed by high-temperature degassing. The vapor pressure characteristic of the fluorocarbon liquid 5 is that the vapor pressure becomes 1 atm at approximately 50°C.Using this characteristic, the fluorocarbon liquid 5 is
If the temperature is maintained at 0° C. or higher, the internal pressure of the evaporator 1 is always maintained higher than atmospheric pressure. In this way, when the internal pressure of the evaporator 1 is made higher than the atmospheric pressure and the valve 10 is opened, the steam inside the evaporator 1 is released to the outside of the evaporator 1, and at the same time, non-condensable gas is also released. The fluorocarbon liquid 5 in the evaporator 1 is heated by energizing the thyristor element 2 . Further, since the fluorocarbon liquid 5 is maintained at a high temperature, dissolved non-condensable gas is well degassed.

[0005]

[Problems to be Solved by the Invention] In the conventional thyristor device as described above, high-temperature deaeration is performed using the vapor pressure characteristics of the fluorocarbon liquid 5, but when an ethylene glycol aqueous solution is used as the cooling medium, The internal pressure of the evaporator 1 is 0.
Since the pressure was maintained at 5 atm or less, there was a problem in that high-temperature deaeration could not be performed satisfactorily. That is, in the case of an ethylene glycol aqueous solution, in order to make the internal pressure of the evaporator 1 higher than atmospheric pressure, the ethylene glycol aqueous solution needs to be heated to 100°C or higher, and the temperature must be higher than the permissible temperature of the boiling cooling device (70 to 80°C). This could cause the device to malfunction.

[0006] This invention was made with the aim of solving the above-mentioned problems, and even when an ethylene glycol aqueous solution is used as a cooling medium, it is possible to remove non-condensable gas without causing equipment failure. An object of the present invention is to obtain a deaeration method for a boiling cooling device that can perform deaeration well.

[0007]

[Means for Solving the Problems] A deaeration method for a boiling cooling device according to the present invention maintains an ethylene glycol aqueous solution as a cooling medium below the freezing temperature, and during this period, evacuates the inside of the boiling cooling device. be.

[0008]

[Operation] In the present invention, the ethylene glycol aqueous solution is kept below the freezing temperature to form a sherbet-like solution, and in this state, the inside of the apparatus is evacuated to degas the non-condensable gas.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an individual cooling fin type boiling cooling device during deaeration by a method according to an embodiment of the present invention. In the figure, 11 is a plurality of evaporators (cooling fins) each having an endothermic surface 11a, and 12 is each evaporator 11.
A common liquid reservoir is connected to the evaporator 11 and the common liquid reservoir 12 via first and second ducts 13 and 14.
An ethylene glycol aqueous solution 15 is placed inside. Further, the first duct 13 is for sending the liquid of the ethylene glycol aqueous solution 15, and the second duct 13 is for sending the liquid of the ethylene glycol aqueous solution 15.
4 is for sending the liquid and vapor of the ethylene glycol aqueous solution 15.

16 is a header provided on the common liquid reservoir 12, 17 is a condenser connected to the header 16, 18 is a first evacuation pipe drawn out from the header 16, and 19 is a first evacuation pipe. a vacuum valve provided at the tip of the pipe 18;
1 is a second vacuum piping whose one end is connected to the vacuum valve 19 and whose other end is drawn out of the cryogenic chamber 20;
2 is a vacuum pump connected to the second evacuation piping 21, and 23 is a vacuum gauge connected to the second evacuation piping 21. Moreover, 30 is an element provided on the heat absorption surface 11a.

Next, the degassing method will be explained. first,
After the inside of the container of the boiling cooling device is evacuated in advance, the ethylene glycol aqueous solution 15 is injected into the container. Next, the container is evacuated at room temperature and the vapor pressure inside the container is measured. At this time, if the vapor pressure is that of the ethylene glycol aqueous solution 15, it is confirmed that there is no non-condensable gas such as air in the space inside the container.

Thereafter, the inside of the cryostat 20 is maintained at a temperature below the freezing temperature of the aqueous ethylene glycol solution 15. Then, for a predetermined period of time, that is, while the ethylene glycol aqueous solution 15 is in a completely unfrozen state (in a sherbet-like state or in a sherbet-like state partially containing liquid), the inside of the container is evacuated by the vacuum pump 22. As a result, the non-condensable gas in the container and the non-condensable gas dissolved in the ethylene glycol aqueous solution 15 are degassed. Thereafter, the vapor pressure inside the container is measured using the vacuum gauge 23, and after confirming that the vapor pressure is equal to that of the ethylene glycol aqueous solution 15 in a low temperature state, the vacuum valve 19 is closed. Normally, when the boiling cooling device is installed in a subway or the like, the first evacuation piping 18 is sealed off after degassing.

According to such a degassing method, even when an aqueous ethylene glycol solution 15 is used as a cooling medium, the boiling cooling device does not malfunction due to high temperatures, and non-condensable gas can be degassed well. Furthermore, since the vacuum is drawn at a temperature below the freezing temperature, the release of the ethylene glycol aqueous solution 15 itself is suppressed, preventing changes in the concentration of the cooling medium, and is also excellent in economical efficiency. Furthermore, in the above embodiment, since the deaeration process is performed before the ethylene glycol aqueous solution 15 is completely frozen, there is no risk of damage to the container due to freezing.

[0014] In the above embodiment, an individual cooling fin type boiling cooling device is shown, but an immersion type cooling device like the conventional example may be used.

[0015]

[Effects of the Invention] As explained above, the degassing method of the evaporative cooling device of the present invention maintains the ethylene glycol aqueous solution, which is the cooling medium, below the freezing temperature, and during this time, the inside of the evaporative cooling device is evacuated. , Even when an ethylene glycol aqueous solution is used as the cooling medium, non-condensable gas can be degassed successfully without causing failure or damage to the equipment and without changing the concentration of the cooling medium. play.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a boiling cooling device in the middle of degassing by a method according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing an example of a conventional evaporative cooling device.

[Explanation of symbols]

Claims (1)

[Claims] Claim 1. A deaeration method for a boiling cooling device for degassing non-condensable gas from a boiling cooling device using an ethylene glycol aqueous solution as a cooling medium, the method comprising: maintaining the ethylene glycol aqueous solution below freezing temperature; A degassing method for a boiling cooling device, characterized in that the inside of the boiling cooling device is evacuated.