JPS6039664Y2 - heat exchange equipment - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a heat exchange device used when hot oil in a transformer or the like is cooled with cooling water.

In such a device, it is not allowed that the cooling water becomes under negative pressure and causes cavitation, nor is it allowed that the cooling water leaks into the pond.

In oil-feed water-cooled transformers, etc., the first priority is to eliminate the heat loss.
A heat exchange device as shown is used.

In other words, the oil, which is the cooled liquid in the transformer 1, is transferred to the oil pump 2.
is cooled through the water-to-oil exchanger 3 and transferred to the transformer 1.
Return to and cycle.

On the other hand, the cooling water is supplied to the water-to-oil exchanger 3 by the pump 4, and the heated cooling water is cooled through a recooler 5 such as a cooling tower, returns to the water tank 6, and is circulated again by the pump 4.

Generally, a large number of pipes are used in the water-oil exchanger 3, and heat exchange is performed by flowing cooling water into the pipes and flowing oil outside the pipes.

In this case, if water leaks inside the heat exchanger, the water will enter the pond and significantly impair the insulation properties of the oil, leading to serious problems.

To prevent these problems, conventional methods have adopted a double pipe system or an open outlet system to make the oil pressure in the heat exchanger higher than the pressure of the cooling water to prevent water from entering the oil.

That is, as shown in Fig. 2, a double pipe heat exchanger 2 is used.
1 is a system in which an oil pipe 24 is arranged concentrically with a cooling pipe 23 through which cooling water 22 passes, and an interval communicating with the atmosphere, and oil 25 flows outside the oil pipe to exchange heat. Since it is discharged outside the vessel, it does not enter the oil.

However, in this structure, since there is air, which is a poor heat conductor, between the oil pipe 24 and the cooling pipe 23, there is a drawback that not only is the heat exchange efficiency poor, but the structure is complicated and expensive.

FIG. 3 shows an outlet open system in which the cooling water outlet 31 of the heat exchanger 3 is opened to an intermediate water tank 32 at approximately the height of the heat exchanger 3 and connected to a recooler (not shown) via a regulating valve 33 and a pump 34. It is something.

In the above configuration, the head loss of the cooling water in the heat exchanger 3 is small, so the pressure of the cooling water in the heat exchanger 3 is maintained at a value slightly higher than atmospheric pressure and lower than the oil pressure.

However, in this method, the water tank 32 is required, and maintenance such as overflow treatment of the water tank is troublesome.

This invention was made in view of the above points, and aims to correct the conventional drawbacks and provide a water-cooled heat exchange device that is simple in structure, inexpensive, and easy to maintain.

For this purpose, according to the configuration of this invention, the cooling water outlet of the heat exchanger is connected to the recooler by a sealed pipe via a line pump, and when the required amount of cooling water is flowed into the heat exchanger, the The pressure head at the cooling water outlet of the heat exchanger is adjusted to a positive pressure close to 0, and the line pump supplies the required amount of cooling water and the head loss after the cooling water outlet of the heat exchanger when this amount of water flows.

As a result, the head loss of the cooling water in the heat exchanger is small, so the water pressure in the heat exchanger becomes a slight positive pressure close to 0, and this pressure is smaller than the oil pressure around the water cooling pipes.

Therefore, even in the unlikely event of a water leakage accident, the water will not enter the oil and there is no risk of any serious consequences.

FIG. 4 shows an embodiment of this invention, in which oil 41, which is the liquid to be cooled, in the transformer 1 is cooled by the oil pump 2 through a water-oil heat exchanger 42, and then returned to the transformer 1 for circulation.

On the other hand, the cooling water 43 is sucked up from the water storage tank 44 under atmospheric pressure by the water supply pump 4 and supplied to the water-heat dissipation exchanger 42 via the regulating valve 45 .

The cooling water outlet of the heat exchanger is connected to a flow meter 46. It is connected to a recooler 50 such as a cooling tower via a regulating valve 47 and a line pump 48 through a sealed pipe 49, and the cooling water 43 is returned to the water storage tank 44 after being cooled by the recooler.

Further, a compound pressure gauge 51 is provided at the cooling water outlet of the heat exchanger 42 to issue an alarm when the pressure is negative or a predetermined positive pressure value.

The heat exchanger 42 is operated by pumps 2.4. Driving 48,
Oil 41 is flowed outside the cooling pipe (not shown), and cooling water 43 is flowed inside the cooling pipe to exchange heat.

Then, the cooling water 43 is passed through the heat exchanger 42 when the required amount of water flows.
The pressure head at the cooling water outlet is adjusted to a positive pressure approximately close to O by the regulating valve 45.

The adjustment is made while observing the coupled pressure gauge 51 and flow meter 46.

The regulating valve 47 is used to regulate the flow rate of the line pump 48.

By configuring the heat exchange device as described above, the outlet side of the cooling water system of the device with the lowest pressure head has a positive pressure close to 0,
Therefore, since the other parts are kept at a positive pressure that is higher by the water pressure corresponding to the loss to the outlet, there is no risk of corrosion caused by separated air due to cavitation.

Also, since the head loss of the cooling water in the heat exchanger is small, even in the highest water system in the heat exchanger, the surrounding cooled liquid (
For example, the pressure head is lower than that of oil), so even if a water leak occurs due to damage to a cooling pipe, there is no risk of the cooling water getting mixed into the liquid to be cooled and causing any serious problems.

FIG. 5 shows a case where a cooling water system of another device (for example, an electric furnace) 60 is connected in parallel with the cooling water system of the heat exchanger 42, and the same reference numerals indicate those having the same functions as described above.

In this case, backflow of the cooling water can be prevented by providing a check valve 61 on the cooling water outlet side of the heat exchanger.

As is clear from the above explanation, the pressure head on the heat exchanger outlet side is adjusted to a positive pressure close to approximately O at the required amount of cooling water by the regulating valve 45 on the cooling water inlet side of the heat exchanger 42, and By providing the line pump 48 with the required amount of water and providing sealed piping to the recooler 50, the pressure of the cooling water system of the heat exchanger can always be kept positive and lower than the pressure of the liquid to be cooled surrounding the cooling water system.

Therefore, it is possible to obtain a reliable heat exchanger without causing cavitation and corrosion, and even in the unlikely event that a water leakage accident occurs, the cooling water will not be mixed into the liquid to be cooled. .

[Brief explanation of the drawing]

Fig. 1 is a cooling water system diagram of a heat exchanger of a conventional example, Fig. 2 is a partial sectional view of a conventional cooler, Fig. 3 is a cooling water system diagram of a heat exchanger of another conventional example, and Figs. FIG. 5 is a diagram of the cooling water system of the heat exchanger according to this embodiment of the invention. 4... Water supply pump, 41... Cooled liquid, 42... Heat exchanger, 43... Cooling water, 44... Water storage Tank, 45... Regulating valve,
48... Line pump, 49... Sealed pipe line, 50... Recooler, 61... Check valve.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. Heat exchange between the liquid to be cooled and cooling water supplied from a water storage tank under atmospheric pressure via a regulating valve by a water supply pump, and the heat exchanged. In a heat exchange device in which cooling water is cooled through a recooler and returned to the water storage tank, a cooling water outlet of the heat exchanger is connected to the recooler by an I closed pipe via a line pump, When the required amount of cooling water flows through the heat exchanger, the pressure head at the cooling water outlet of the heat exchanger is adjusted to a positive pressure close to 0 using the regulating valve, and the line pump adjusts the amount of cooling water to the recooler. A heat exchange device characterized by supplying. 2. A heat exchanger according to claim 1 of the utility model registration, characterized in that a check valve is provided on the cooling water outlet side of the heat exchanger.