JPH0145965B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an evaporatively cooled gas insulated electrical device, and particularly to a cooler aimed at improving cooling efficiency and reducing the size and weight of the cooler.

[Prior art]

BACKGROUND ART Conventionally, there has been a so-called evaporative cooling method that utilizes a refrigerant that undergoes a phase change as an efficient means of dissipating internal heat generation in electrical equipment such as transformers. An example of this method is shown in FIG.

In the figure, an electric device 1 that generates heat is housed in a tank 2, and a cooler 3 and the tank 2 communicate with each other via upper and lower headers 4a and 4b. The tank is filled with a non-condensable gas 9 (hereinafter referred to as gas) and a refrigerant that undergoes a gas-liquid phase change when heat is transferred, and the liquid refrigerant 5 is stored at the bottom of the tank. The liquid is discharged into the tank 2 through the piping 7 by the liquid pump 6, and sprayed onto the electric equipment 1 which generates heat. A part of the liquid phase refrigerant 5 sprayed on the electrical equipment 1 absorbs heat from the electrical equipment 1 and at the same time vaporizes to become refrigerant vapor 8, but if the specific gravity of this refrigerant vapor 8 is greater than the specific gravity of the gas 9. At this time, the refrigerant vapor 8 sinks downward and stagnates, and also enters the cooling duct 10 through the lower communication pipe 12 and the lower header 4b. Therefore,
This cooling duct 10 releases heat and at the same time refrigerant vapor 8
The refrigerant is liquefied, and heat is radiated according to the heat radiating capacity of the cooler using this refrigerant as a heat transporter. In such a cooling system, the refrigerant vapor 8 stagnates downward due to the difference in specific gravity, and the gas 9 is forced upward. Occur. however,
Since refrigerant vapor 8 is constantly generated from electrical equipment that generates heat, there is actually a clear boundary 1 inside the tank 2.
3 is less likely to occur, but the boundary surface that is imagined based on the volume ratio of each refrigerant vapor gas depending on the pressure will be referred to as the boundary surface 13 here. In the configuration shown in FIG. 1, that is, when the tank 2 and the cooler 3 are in communication through the upper and lower headers 4a and 4b and the upper and lower communication pipes 14 and 12, this boundary surface 13 is formed between the cooler 3 side and the inside of the tank 2. The cooling duct 10 of the cooler 3 is always at the same height H ₀ of the boundary surface 13, and the part above the boundary surface 13 is filled with gas 9 with low heat transport ability. This means that it contributes to effective heat dissipation only up to ₀ . Therefore,
Even if a large cooler was installed, the drawback was that the utilization rate of the cooling area was extremely low. Note that the reference numeral 11 is a blower for heat radiation.

[Summary of the invention]

The present invention aims to eliminate the drawbacks of the conventional device described above, improve the utilization rate of the cooling area, and thereby obtain a small evaporative cooling type gas insulated electrical device with a large heat dissipation capacity. It's hot,
Constant cooling is achieved by installing a check valve in the middle of the upper communication pipe that allows non-condensable gas to flow only from the upper header to the tank, and a gas pump that discharges non-condensable gas from the upper header to the tank. To provide an evaporative cooling type gas insulated electrical device in which as much refrigerant vapor as possible is present in a cooling duct within the device to increase heat radiation efficiency, thereby reducing the size of the cooler.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on figures showing examples thereof.

First, in FIG. 2, a check valve 21 is provided in the middle of the upper communication pipe 14 that connects the upper header 4a and the tank 2. This valve allows ventilation, but prevents ventilation from the tank 2 to the upper header 4a. Further, the gas pump 22 is a gas pump that sends non-condensable gas in the upper header 4a to the tank 2.

The present invention is configured as described above, and its operation will be described next.

First, the operation of the cooling system when the gas pump 22 is stopped will be described.

In this state, when the electrical equipment 1 takes on a load and generates heat, the liquid phase refrigerant 5 is sprayed onto the electrical equipment 1, absorbs the heat of the electrical equipment 1, vaporizes, and generates refrigerant vapor 8. are separated due to the difference in specific gravity, and an interface 13 is generated between the gas 9 and the refrigerant vapor 8.
In this state, as the steam temperature rises, the steam pressure increases, and the gas 9 is pushed upward. However, because the check valve 21 is provided, the gas volume on the tank 2 side and the gas volume of the cooler 3 are each compressed separately. Therefore, although the compression ratio of each volume is the same, if the volume of the upper header 4a is set larger, for example, about 10 times the volume of the cooling duct 10 of the cooler 3, the volume of the cooler 3 side The boundary surface 13 of the cooling duct 1
Until reaching the upper end of 0, if the height change of the boundary surface 13 due to the increase in refrigerant vapor pressure is △h on the tank 2 side, the boundary surface height will rise by about 10△h in the cooling duct 10. Therefore, with a slight increase in pressure, the inside of the cooling duct 10 is filled with refrigerant vapor. Therefore, the effective cooling area of the cooler 3 can be increased compared to the conventional device shown in FIG.

However, such a state has the following drawbacks. That is, (1) In order to completely fill the cooling duct 10 with refrigerant vapor as described above, it is necessary to provide a large-volume upper header 4a, which results in an increase in the size of the device.

(2) Gas 9 gradually enters the cooler 3 along with refrigerant vapor from the tank 2 side through the lower communication pipe 12, accumulates over time, and forms the boundary surface 1 inside the cooler 3.
3, and the amount of heat dissipation gradually decreases.

When such a state occurs, it is necessary to discharge the gas 9, and a case where the gas pump 22 is temporarily operated for this purpose will be described below.

As shown in FIG. 3, when the gas pump 22 is operated to transfer the gas 9 in the upper header 4a into the tank 2, the refrigerant vapor rises upward in the cooling duct 10 instead, causing cooling. The effective cooling area of the container 3 can be increased. This state is shown in FIG. According to this, the gas 9 in the upper header 4a is transferred into the tank 2 by the gas pump 22, so there is no need to determine the volume of the upper header 4a by the ratio of the volume of the cooling duct 10, and the small upper header Even 4a will be fine. Moreover, since the gas 9 that accumulates over time is transferred again into the tank 2 by the gas pump 22, there is no deterioration of the boundary surface, and therefore, continuous operation of the apparatus is possible.

Moreover, the pressures in the tank 2 and the cooler 3 are the same everywhere, if the positional head is ignored; in other words, the pressures in the refrigerant vapor layer and the gas layer are the same. Therefore, even if the gas pump 22 is stopped after the gas is transferred, the pressure equilibrium will not be disrupted, so the boundary surface 13 will not be pulled up unless new gas 9 is supplied into the cooler 3 through the lower communication pipe 12. It stays still and does not descend.

Furthermore, although the gas pump 22 may be in continuous operation, it is not necessary to do so, and may be operated intermittently at intervals of a certain period of time as long as the interface height can be maintained. However, when the gas pump 22 is continuously operated and always used, the pump operation itself has a backflow prevention function, so the discharge of the gas pump 22 is adjusted to correspond to the amount of gas 9 accumulated in the upper header 4a. It is necessary to set the amount.

Next, another embodiment of the present invention is shown in FIGS. 5A and 5B. In this embodiment, instead of a check valve and a gas pump, a check valve 31a is installed in the internal gas passageway of the upper communication pipe 14, as shown in FIG. 5B, to transfer the gas 9. A positive displacement pump 31 is inserted, whereby the cooling system operates in the same way as in the embodiment of the invention shown in FIG. In FIG. 5B, reference numeral 31b is a pump-driven piston, arrow X indicates the flow of gas 9, the Y side is connected to the upper header 4a, and the Z side is connected to the tank 2.

According to this, from the tank 2 to the upper header 4a
Since the check valve 31a that blocks the gas flow toward the pump is incorporated as a component inside the volumetric pump 31, there is no need to separately install a check valve in the communication pipe. It has the advantage of further promoting compactness and weight reduction, as well as improving maintainability.

〔Effect of the invention〕

As described above, the present invention provides a check valve and a gas pump in the middle of the upper communication pipe to discharge gas into the tank and prevent backflow from the tank to the cooler. The cooling efficiency can be improved by filling the air with refrigerant vapor as much as possible, which has the effect of making it possible to obtain an evaporatively cooled gas-insulated electric device that can downsize the cooler, that is, the device. are doing.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of a conventional evaporative cooling type gas insulated electric device, FIG. 2 is a schematic sectional view of an embodiment of the present invention, and FIG. 3 is an explanatory sectional view of the state of FIG. FIG. 4 is an explanatory sectional view when a large amount of refrigerant vapor is generated in FIG. 2, FIG. 5A is a schematic sectional view of another embodiment of the present invention, and FIG.
FIG. 3 is a schematic cross-sectional view of the pump 31 of FIG. 1...Electrical equipment, 2...Tank, 3...Cooler, 4a...Upper header, 4b...Lower header, 5...Liquid phase refrigerant, 6...Liquid pump, 7...
Piping, 8... Refrigerant vapor, 9... Non-condensable gas (gas), 10... Cooling duct, 11... Air blower, 1
2...Lower communicating pipe, 13...Boundary surface, 14...Upper communicating pipe, 21...Check valve, 22...Gas pump, 31...Volume pump. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. Consisting of an electrical device, a tank that houses the same, and a cooler that radiates heat generated from the electrical device to the outside, the tank contains non-condensable gas and its The cooler is filled with a refrigerant having a vapor specific gravity greater than that of the non-condensable gas and which undergoes a gas-liquid phase change, and the cooler communicates with a plurality of upright cooling ducts and the respective cooling ducts at both upper and lower ends of the cooling ducts. In an evaporative cooling type gas insulated electric device in which refrigerant vapor and non-condensable gas are separated and operated by providing upper and lower headers that communicate with the inside of the tank through upper and lower communication pipes, the upper communication pipe A check valve that vents non-condensable gas only from the upper header to the tank and a gas pump that discharges the non-condensable gas from the upper header into the tank are installed in the middle of the pipe. Evaporatively cooled gas insulated electrical equipment. 2. Claim 1, wherein the gas pump is constantly operated with an air supply amount corresponding to the amount of non-condensable gas flowing into the cooler while the electrical equipment is operating.
Evaporatively cooled gas insulated electrical equipment as described in . 3. The evaporative cooling type gas insulated electricity according to claim 1 or 2, wherein the check valve and gas pump provided in the middle of the upper communication pipe are pumps incorporating a one-way ventilation valve. Device.