JPS5816237Y2 - Liquid drying detection device for liquid immersion type electrical equipment - Google Patents

Description

[Detailed explanation of the invention] This invention, like the fluorocarbon boiling cooling semiconductor converter, stores electrical equipment in a sealed container, fills it with cooling liquid, and cools the electrical equipment by boiling or convection of the liquid. In order to prevent coolant from leaking from immersed electrical equipment for some reason, the temperature of the internal electrical equipment may rise due to a drop in the liquid level or the liquid dries up, eventually leading to burnout. The present invention relates to a device for detecting a drop in the liquid level or drying up of a coolant.

FIG. 1 is a block diagram of a conventional liquid depletion detection device for a fluorocarbon evaporative cooling semiconductor conversion device.

Conventionally, this type of protection device includes a semiconductor stack 3 immersed in a cooling liquid 2 inside a closed container 1, as shown in FIG.
A temperature sensor 6 is attached directly to the conductor/cooling fin 4 of each element, and this temperature sensor 6 detects a temperature rise in the semiconductor stack 3 due to a drop in the coolant level or drying up of the coolant, and detects the temperature rise above the allowable temperature. The system was designed to prevent abnormal heating by stopping power supply when

The disadvantages of such conventional devices are that since the temperature sensor is housed inside a sealed container, maintenance, inspection and replacement during use are difficult, and extremely high reliability is required of the temperature sensor; Equipped with multiple temperature detectors to improve reliability may lead to an increase in the cost of the equipment.

In addition, special consideration must be given to the sealed terminal 7 for leading the lead wire 61 of the temperature sensor out of the container in order to maintain airtightness, which complicates the structure and workmanship, reducing the reliability of the entire device. There are also drawbacks.

The purpose of this invention is to eliminate the above-mentioned drawbacks and provide a liquid drying up detection device with a simple structure.

FIG. 2 shows an embodiment of this invention.

In the figure, 8 is a sealed terminal for drawing out the lead-out conductor 9 of the semiconductor stack 3 to the outside of the container 1, and 6 is a temperature sensor attached to the terminal conductor 10 of the sealed terminal 8 drawn out to the outside of the container 1. It is.

Since the lead-out conductor 9 and the sealed terminal 8 are provided at a slightly higher position than the semiconductor stack 3 housed in the container, when the coolant level drops, the lead-out conductor 9 portion is exposed above the liquid level. do.

The temperature rise in the lead-out conductor 9 is due to loss due to its own electrical resistance and also due to heat transmitted from the cooling fins of the semiconductor stack 3 inside, but the semiconductor stack 3 is sufficiently cooled down to the lead-out conductor 9. When immersed in the liquid, the heat transfer from the semiconductor stack 3 is small, and the lead conductor 9 is also cooled by the cooling liquid, so the temperature of the lead conductor 9 becomes a low value.

Therefore, in this state, the temperature of the terminal conductor 10 of the sealed terminal 8 coupled to the lead-out conductor 9 is also low.

The bowed conductor 9 and terminal conductor 1 are damaged due to liquid leakage on the coolant surface.
When the temperature drops below 0 and these conductors become exposed, the temperature of the lead conductor 9 increases because the cooling effect of the cooling liquid disappears, and the temperature of the lead conductor 9 becomes somewhat higher than the temperature of the semiconductor stack 3 inside. .

Since there is good heat conduction between the drawer conductor 9 and the terminal conductor 10, the temperature rise of the bowed conductor 9 inside the container will increase to the terminal conductor 10 outside the container.
The temperature of the terminal conductor 10 also increases.

Therefore, the temperature detector 6 attached to the terminal conductor 10 outside the container detects such a temperature rise in the drawer conductor 9 inside the container, and as a result, the coolant level in the container 1 drops below the level of the drawer conductor 90. However, since it is detected that the bowed conductor 9 is exposed from the coolant, an alarm (not shown) can warn of a drop in the liquid level.

When only the lead conductor 9 is exposed from the coolant 2, the semiconductor stack 3 is still safe because it is cooled by the coolant, but the level of the coolant drops further and the semiconductor stack 3 is exposed below the liquid level. When this happens, the cooling effect on the semiconductor stack 3 disappears, and the temperature of the stack 3 rises rapidly. This is transmitted to the lead-out conductor 9 and the terminal conductor 10, so that the temperature of the terminal conductor 10 also rises rapidly.

If the temperature detector 6 detects such a temperature rise, the power supply to the semiconductor stack 3 is cut off by a protection device (not shown), thereby preventing the semiconductor stack 3 from burning out due to overheating.

According to this invention, it is possible to detect a drop in the level of the coolant and the liquid drying up by simply attaching an inexpensive temperature sensor to the conductor of the sealed terminal extended outside the container, which is not necessary in the past. The sealed terminal for the lead wire of the temperature sensor is no longer necessary, simplifying the structure and improving reliability.

In addition, maintenance and inspection of the temperature detector can be carried out freely and easily, and a drop in the coolant level can be detected in two stages, which is useful for improving safety.

This invention can be applied not only to fluorocarbon boiling-cooled semiconductor conversion devices but also to general electrical equipment that is cooled by being immersed in oil or other cooling liquids.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional device, and FIG. 2 is a sectional view of essential parts showing an embodiment of this invention. DESCRIPTION OF SYMBOLS 1... Airtight container, 2... Cooling liquid, 3... Semiconductor stack, 4... Cooling fin, 5... Semiconductor element,
6... Temperature detector, 7... Sealed terminal for temperature detector,
8... Main circuit sealed terminal, 9... Output conductor, 10...
...Terminal conductor.

Claims (1)

[Scope of Claim for Utility Model Registration] ■) In a liquid immersion type electrical device that cools the electrical device by immersing it in a cooling liquid filled in a sealed container, the lead-out conductor of the electrical device is connected to the outside of the container via a sealed terminal. A liquid depletion detection device for liquid immersion type electric equipment, characterized in that a temperature sensor is attached to a conductor drawn out of the container. 2) Utility Model Registration Scope of Claims 1. The device for detecting liquid drying up in an immersion type electric device, wherein the sealed terminal is provided at a higher position than the top surface of the electric device inside the container. .