JPS6321333B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling device for both natural circulation cooling and forced circulation cooling, which prevents malfunction of a failure detection device of an electric appliance or the like to which an oil pump is installed when the oil pump is started or stopped.

In the forced circulation cooling system for transformers, etc., as shown in Figure 1, oil is suddenly sent into the oil tank 3 from the radiator 2 when the oil pump 1 is started, but the viscosity of the oil and the heat radiator may change momentarily. Due to the fluid resistance of the radiator 2, oil is not replenished and the radiator 2 is recessed as shown by the dotted line. The oil corresponding to this depression suddenly flows into the conservator 4, causing the failure detection device 5 to malfunction. In order to prevent this, as shown in Fig. 2, two radiators 2 are connected in series as a pair, and an oil feed pump 1 is arranged in an intermediate pipe line communicating between the radiators 2 of the pair, and the pump is started and stopped. When one radiator becomes under positive pressure and becomes convex, the other radiator becomes concave, and the changed oil amount cancels each other out, leaving almost no change in the oil amount in the oil tank 3, resulting in a failure. The detection device 5 employs a method that prevents malfunctions.

On the other hand, for electrical appliances and the like that use oil pumps for forced circulation cooling, a system is adopted in which forced circulation cooling is performed during heavy loads, and natural circulation cooling is used during light loads to save on loss of auxiliary equipment such as pumps. but,
In the conventional device shown in FIG. 2, in which the paired radiators are arranged at approximately the same height due to the height of the oil tank, the conventional device shown in FIG. 1, which is operated in parallel, has a pump for each radiator. This method has the advantage of reducing the number of pumps by half compared to conventional methods, but in the case of natural circulation cooling, oil must be flowed against gravity in intermediate management, which has the disadvantage that the cooling effect is significantly reduced.

This invention was made in view of the above-mentioned points, and it is natural that even in the case of natural circulation cooling, the cooling efficiency does not decrease significantly as in the conventional case, and the number of oil feed pumps is reduced, and the failure detection device does not malfunction as described above. The purpose of the present invention is to provide an oil cooling device that can be used for forced circulation. This objective is achieved by the following configuration. That is, the upper part of one radiator communicates with the upper part of the oil tank, and the lower part of the radiator is located above the lower part of the one radiator through an intermediate pipe line equipped with an oil pump. In the oil cooling device for both natural and forced circulation, the oil cooling device is equipped with at least two radiators forming a pair, the upper part of the radiator communicating with the upper part of the radiator, and the lower part of the other radiator communicating with the lower part of the oil tank. A branch pipe line that communicates between the lower part of the channel and the lower part of the oil tank, and a branch pipe line that communicates the upper part of the intermediate pipe line and the upper part of the oil tank are provided, and each branch pipe line includes: A blocking valve is provided that closes when the oil pump is in operation and opens when it stops.

FIG. 3 shows the piping of the cooling device according to the embodiment of the present invention. This device comprises at least two radiators 31 and 32 in a pair, the upper part of the first radiator 31 communicates with the upper part of the oil tank 3, and the lower part communicates with the intermediate pipe 33 equipped with the oil pump 1. via the first heat radiator 31
The second heat radiator 32 is connected to the upper part of the second heat radiator 32 located above the lower part of the second heat radiator 32 (both heat radiators 31 and 32 are at approximately the same height in the figure). Also, the lower part of the second radiator 32 is the oil tank 3.
It communicates with the lower part of. The lower part of the intermediate pipe 33 communicates with the lower part of the oil tank 3 via a branch pipe provided with a blocking valve 34 . The blocking valve 34 is closed by the oil pressure when the oil feed pump 1 is operated.
Alternatively, it may be a valve that closes electrically and opens when the oil pump is stopped. The upper part of the intermediate pipe 33 is connected to the oil tank 3 through a branch pipe equipped with another check valve 35.
It communicates with the upper part of. With this configuration, when the oil pump 1 is in operation, that is, during forced circulation cooling, oil passes from the top of the oil tank 3 in series through the first and second radiators 31 and 32 as shown by the solid line arrows. Return to bottom. The blocking valves 34 and 35 are closed when the oil feed pump 1 is in operation, and oil flow to the oil tank 3 is blocked. During natural circulation cooling, the oil feed pump 1 does not operate, so the blocking valves 34 and 35 open, and the oil flows from the top of the oil tank 3 to both the radiators 31 and 32 as shown by the dotted line.
flows in parallel and returns to the lower part of the oil tank 3. Since the oil speed during natural circulation is very slow, oil feed pump 1 and check valve 3
The oil flow resistance due to 4 and 35 is small, so the radiator 3
The cooling efficiency of 1.32 is the same as that of a general radiator,
Moreover, even during natural circulation cooling, there is no need for any manual operation of valves or the like, and when forced circulation is stopped, the natural circulation cooling state is automatically returned. Furthermore, when the oil pump 1 is started or stopped, the pressures in the radiators 31 and 32 are contradictory to each other, and therefore, as indicated by the dotted line, changes in the amount of oil in the radiators due to deformation of the radiator cancel each other out, resulting in a failure. There is no malfunction of the detection device 5.

FIG. 4 is a diagram showing another embodiment of the present invention, in which the same reference numerals indicate those having the same functions as those described above. As shown in FIG. 3, the radiators 31 and 32 are not connected to the oil tank 3 independently, but are connected together, which has the advantage of reducing the number of butterfly valves 41 by half.

As is clear from the above description, according to the present invention, during forced circulation cooling, the two radiators 31 and 32 are connected in series to increase the oil speed, and during natural circulation, the blocking valve 34,
Natural and forced circulation that leads hot oil from the upper part of the oil tank 3 to both radiators 31 and 32 in parallel via 35, and shortens the flow oil path to match cooling efficiency and prevent malfunction of the failure detection device. We were able to obtain a dual-purpose oil cooling device.

[Brief explanation of the drawing]

1 and 2 are piping diagrams of a conventional forced circulation cooling device, and FIGS. 3 and 4 are piping system diagrams of different embodiments of the present invention. 1...Oil pump, 3...Oil tank, 31...1st
radiator, 32... second radiator, 33... intermediate pipe, 34, 35... blocking valve.

Claims (1)

[Claims] 1. An intermediate pipe line comprising a pair of first and second radiators, an upper part of the first radiator communicating with the upper part of the oil tank, and a lower part of the first radiator equipped with an oil pump. In an oil cooling device, the oil cooling device communicates with the upper part of the second radiator located above the lower part of the first radiator, and the lower part of the second radiator communicates with the lower part of the oil tank, a branch pipe line that communicates a lower part of the intermediate pipe line and a lower part of the oil tank;
A branch pipe is provided that communicates the upper part of the intermediate pipe with the upper part of the oil tank, and each branch pipe is provided with a blocking valve that closes when the oil pump is in operation and opens when it stops. A natural and forced circulation oil cooling system.