JP3437732B2 - Water-cooled electrical equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to water-cooled generators, fuel cells, and other water-cooled electrical equipment.

[0002]

2. Description of the Related Art Generally, a water-cooled electric device has many electric devices as objects to be cooled. A metal joint installed in a cooling water pipe is connected to this cooling electric device via an insulating pipe, and cooling water supplied via the cooling water pipe flows into the electric device to cool the electric device. .

FIG. 5 shows the overall structure of a conventional water-cooled electric device. In FIG. 5, 1 is a circulation pump for the cooling water W, 2 is a heat exchanger, and 3 is an ion exchange resin tower for keeping the quality of the cooling water W at high purity (low conductivity). 4 is a cooling water pipe formed in an annular shape so as to include the circulation pump 1 and the heat exchanger 2. 5 is a cooling water pipe 4 formed in an annular shape so as to include the ion exchange resin tower 3 and an entrance / exit point of the circulation pump 1. It is a water treatment pipe for the cooling water W connected by P and Q. 6
Is a flow rate control valve provided upstream of the ion exchange resin tower 3 in the water treatment pipe 5, 7 is an electric device provided downstream of the heat exchanger 2 in the cooling water pipe 4, and 8 is a metal joint 9 and cooling. An insulating pipe connected between the end of the water pipe 4 and the metal joint 9,
Reference numeral 10 is a storage tank for the cooling water W that communicates with the communication point Q of the cooling water pipe 4 via the pipe 11. Further, a voltage is applied to the electric device 7, and a potential difference is generated between the metal joints 9 connected to both ends of the insulating pipe 8.

Next, the operation of this conventional water-cooled electric equipment will be described. When the circulation pump 1 is operated, a part of the cooling water W is sent to the cooling water pipe 4 side and is supplied to the heat exchanger 2, while the rest of the cooling water W is sent to the cooling water pipe 5 side and the ion exchange resin. It is supplied to the tower 3. In this case, the ratio between the flow rate on the cooling water pipe 4 side and the flow rate on the cooling water pipe 5 side is determined by the opening degree of the flow rate adjusting valve 6. Then, the cooled cooling water W is supplied into the electric device 7 through the heat exchanger 2 to cool the electric device 7, and then the circulation pump 1 is again supplied.
Returned to the side.

FIG. 6 shows details around the metal joint 9 connected to the insulating pipe 8. The metal joints 9 are attached to both ends of the cooling water pipe 4, and the tip portions 9a of the metal joints 9 are insulated pipes 8.
It is plugged in. Then, the end portion 8a of the insulating tube 8 bent into a flange shape and the metal joint 9 are attached to the cap nut 12.
The cooling water flows through the insulating pipe 8.

By the way, metal parts such as copper and iron are used in the water circulation system of the water-cooled electric equipment. When these parts corrode, metal ions (cations) are generated in the cooling water as shown in the following formula. To generate.

M → M ^{n +} + ne ... In the formula, M represents a metal, n represents a valence, and e represents an electron.

Since a potential difference is generated between the metal joints 9 connected to both ends of the insulating pipe 8, when metal ions reach the vicinity of the metal joint 9 on the low potential side, they adhere to the metal joint 9.

M ^{n +} + ne → M ··· ^{Mn +} + nH ₂ O → M (OH) _n + nH ⁺ · · · · M (OH) _n is a metal hydroxide .

The above formulas, metals and metal hydroxides in the formulas are corrosion products, and other metal oxides are also conceivable.
When these corrosion products grow along the insulating tube 8, the insulating tube 8 is contaminated, so that the withstand voltage of the insulating tube 8 may be reduced and a short circuit may occur.

In order to prevent this short circuit, it is sufficient to prevent corrosion of the metal parts, which is the cause of the generation of corrosion products.
As an anticorrosion method for such metal parts, for metal parts having a potential difference, adoption or coating of a corrosion-resistant material is considered, while for metal parts having no potential difference,
It may be possible to adopt or coat a corrosion resistant material, prevent oxygen from dissolving in cooling water, or remove dissolved oxygen.

That is, the metal parts include a part having a potential difference such as a metal joint and a part having no potential difference such as a heat exchanger.

In a component having a potential difference, for example, a metal joint, a metal joint having a high potential is corroded. As a measure for preventing this corrosion, it is conceivable to adopt a corrosion resistant material such as stainless steel or coat the part with a corrosion resistant material such as TiN.

In addition, a component having no potential difference generally corrodes when dissolved oxygen exists in the cooling water. As a countermeasure, adoption or coating of a corrosion resistant material such as stainless steel can be considered. The use of corrosion resistant materials and coatings to prevent corrosion of metal parts may be difficult to apply depending on the type of metal part. For example, a heat exchanger, which is one of metal parts, is generally made of copper in consideration of cooling performance, but if the material is changed to another material for corrosion protection, the cost becomes high. Therefore, the material change may be limited depending on the type of metal parts, and it is difficult to completely suppress corrosion.

On the other hand, as another anticorrosion method for metal parts having no potential difference, it is possible to prevent dissolution of oxygen into cooling water which is a cause of corrosion or to remove dissolved oxygen. , Can not completely remove dissolved oxygen.

That is, since there is a potential difference between the metal joints connected to both ends of the insulating pipe, if the potential difference is large, oxygen or hydrogen is electrolyzed by water as shown in the following equation, It occurs on the surface.

On the metal joint surface on the high potential side, 2H ₂ O → O ₂ + 4H ⁺ + 4e ···· On the metal joint surface on the low potential side, 2H ₂ O + 2e → H ₂ + 2OH ⁻ ·. ...... Therefore, when there is a potential difference between the metal joints at both ends of the insulating pipe, dissolved oxygen exists in the water circulation system, and the metal parts are corroded. Therefore, it is difficult to completely suppress the corrosion of the metal parts in which no potential difference is generated.

By the way, in order to remove the corrosion products,
For example, cleaning with a sponge ball is performed (see Japanese Patent Application Laid-Open No. 2-272300). However, when this method is applied to a water-cooled generator, the insulating pipe with the dirt attached must be removed, so that workability is reduced.
Therefore, it is necessary to prevent dirt from adhering to the insulating tube.

From the above, in order to prevent the withstand voltage of the insulating tube from decreasing, it is necessary to prevent corrosion products from adhering to the insulating tube on the assumption that the metal parts are corroded. .

[0020]

As described above, when there is a potential difference between the metal joints located at both ends of the insulating pipe, the metal ions generated by corrosion of the metal parts are on the low potential side. If it adheres to and grows along the insulating tube, the withstand voltage may decrease and short circuit may occur. In recent years, along with the trend toward miniaturization and higher performance of water-cooled electric devices, the length of the insulating tube tends to be shortened, and therefore, short-circuit countermeasures are indispensable.

The present invention has been made to solve the above problems, and is effective even when a high voltage is applied between the metal joints and the length of the insulating tube is shortened. An object of the present invention is to provide a water-cooled electric device capable of preventing a withstand voltage drop.

In the water-cooled electric device of the present invention, at least the circulation pump, the heat exchanger, and the storage tank of the cooling water are piped to the object to be cooled through the insulating pipe, and the connecting members are connected to both ends of the insulating pipe. a water-cooled electric equipment potential difference is generated, adhesion prevention means for preventing the adhesion of dirt to the insulating tube to the low potential side metal fitting is provided with, and said adhesion preventing means is in, Insert into the insulation tube
Form an annular groove on the outer peripheral surface of the tip of the metal fitting
Which is a stepped tip of the metal joint,
The tip end surface of the stepped tip portion hangs down in the longitudinal direction of the insulating pipe.
Jikadea is characterized in Rukoto.

[0023]

[0024] Of the insulating pipe and the metal joint on the stepped tip.
To prevent cooling water from accumulating between the stepped tip
A running channel is preferably provided.

[0025]

Further , the water-cooled electric equipment of the present invention is
Tight circulation pump, heat exchanger and cooling water storage
The tank is connected to the object to be cooled through an insulating pipe,
There is a potential difference between the metal fittings connected to the ends of the edge pipe.
A water-cooled electric device that
Adhesion prevention means to prevent the adhesion of dirt to the insulation pipe
Provided, and said adhesion preventing means, wherein to form the tape <br/> Pakatto surface on the tip outer peripheral surface of the fitting portion of the inserted the metal joint insulating tube, at the tapered tip of the metal fitting
It is characterized by being .

It is preferable that the tapered tip portion is provided with a flowing water passage for preventing retention of cooling water between the insulating pipe and the tapered tip portion of the metal joint.

[0028]

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

[Embodiment 1] FIG. 1 is a cross-sectional view of essential parts showing a metal joint in a water-cooled electric apparatus according to Embodiment 1 of the present invention. The basic structure of the water-cooled electric device is the same as that of the water-cooled electric device shown in FIG. 5, and at least the circulation pump, the heat exchanger and the storage tank of the cooling water are electric devices to be cooled through an insulating pipe. Is piped to
A potential difference is generated between the metal joints 9 which are connecting members connected to both ends of the insulating pipe 8.

The metal joint 9 on the low potential side is provided with an adhesion preventing means for preventing the adhesion of dirt to the insulating pipe.

As the adhesion preventing means, a stepped tip portion 14 of the metal joint 9 is formed by forming an annular groove 13 on the outer peripheral surface of the tip of the fitting portion of the metal joint 9 inserted into the insulating pipe 8.
Has been adopted. The stepped tip portion 14 is separated from the insulating pipe 8 by the annular groove 13. Metal fittings 9, which is the distance of the long side direction of the longitudinal is the distance perpendicular to the direction between the stepped distal portion 14 of the insulating tube 8 and the metal fitting 9 length X1 and the insulation tube 8 of the insulating tube 8 Stepped tip 14
The length Y1 of X is not particularly limited, but is usually X1 = 0.
It is 5 mm or more and Y1 = 2 mm or more.

According to the first embodiment, the stepped tip of the metal joint on the low potential side tries to grow in the cooling water toward the metal joint on the high potential side. Since the deposits are peeled off by, the growth of the deposits is prevented. The deposits peeled off from the stepped tip of the metal joint circulate in the cooling water. If the cooling water is maintained at a high purity (low conductivity), it will be redissolved into metal ions that will be captured by the ion exchange resin, so that the deposits can be removed. Alternatively, in order to remove the deposits from the cooling water, it is preferable to install a filter in the circulation path of the cooling water, for example, before the cooling water flows into the ion exchange resin tower (any part of the water pipe 5).

[Embodiment 2] FIG. 2 is a cross-sectional view of an essential part showing a metal joint in a water-cooled electric device according to Embodiment 2 of the present invention. This metal joint has an electric field concentration shape with an acute angle at its tip in order to prevent dirt from adhering to the insulating pipe. The electric field concentration shape may be such that the tip of the metal joint has an acute angle. For example, as shown in FIG. 2, the tip end outer peripheral surface of the fitting portion of the metal joint 9 inserted into the insulating pipe 8 is tapered. Cut surface 1
It may be the tapered tip 15 of the metal joint forming 5a. The length X2 between the insulating pipe 8 and the tapered tip portion 15 of the metal joint 9 which is the distance in the direction perpendicular to the longitudinal direction of the insulating pipe 8 and the length of the metal joint 9 which is the distance in the longitudinal direction of the insulating pipe 8. The length Y2 of the tapered tip portion 15 is
Although not particularly limited, usually X2 = 0.5 mm or more, Y
2 = 2 mm or more.

[Third Embodiment] FIG. 3 is a cross-sectional view of a principal part showing a metal joint in a water-cooled electric device according to a third embodiment of the present invention. In order to further suppress the attachment of dirt as compared with the first and second embodiments, as shown in FIG. 3, the metal joint 9 has its tip portion 16 separated from the insulating pipe 8 and has a thickness A flowing water channel 17 penetrating in the vertical direction is provided. As a result, the tip portion 16 of the insulating pipe 8 and the metal joint 9 is
Since the cooling water 18 can be prevented from accumulating during that time, the metal ions are not concentrated even under the condition that a higher voltage is applied, and the adhesion of dirt to the metal joint 9 can be prevented more effectively. Figure 3
The metal joint of (1) has a flowing water channel provided at the tip of the metal coupling shown in FIG. 1, but a water flowing channel can be similarly provided at the tip of the metal coupling shown in FIG.

[0036] FIG. 4 shows the inventionReference exampleWater-cooled electricity
It is a principal part sectional view which shows the metal joint in an apparatus. This money
The metal joint 9 is non-conductive on the tip surface of the fitting portion 19 of the metal joint.
The member 20 is coated. Non-conductive
As the member 20, for example, glass or Al₂O₃Such as
Ramix can be used. Coating thickness
Is not particularly limited, but is usually 1 μm or more.

Corrosion products adhere to the inside 21 of the tip of the metal joint on the low potential side due to the potential difference between the metal joints.
Since it is stripped off by the flow of cooling water, the growth of deposits is hindered.

[Embodiment 1] In order to investigate the prevention of adhesion of dirt to the insulating pipe, a cooling water circulating device simulating the water cooling type electric equipment shown in FIG. 5 was manufactured, and the stepped tip end portion as shown in FIG. An experiment was conducted in which the formed metal joint and the conventional metal joint shown in FIG. 6 were compared. The experimental conditions were electric field strength between metal joints = 1 kV / cm, conductivity of cooling water = 1.0 μS.
/ Cm or less, the flow rate of cooling water = 1 m / s, and a copper tube was installed to simulate the water contact part of the heat exchanger.

As a result of the experiment, in the low potential side metal joint shown in FIG.
Did not grow along the insulating tube. On the other hand, conventional metal joints on the low potential side were required to have deposits at their tips, which grew along the insulating tube.

By the way, the length of the stepped tip portion of the metal joint was X1 = 0.5 mm and Y1 = 2 mm. Therefore, the longer the length X1 is, the farther it is from the insulating tube. On the other hand, the length Y must be made longer as the electric field strength increases, but under the above experimental conditions, growth of the deposit can be prevented if at least Y1 = 2 mm. As a result of analyzing the deposit, it was found to be copper oxide, which is a corrosion product of a copper pipe. After the copper pipe installed in the cooling water circulation device corrodes and produces copper ions, it is oxidized by dissolved oxygen in the cooling water until it reaches the metal joint, or after copper ions are deposited on the metal joint as metallic copper, It is considered to have been oxidized by dissolved oxygen in the cooling water. Copper oxide has conductivity, and when it grows along the insulating tube and reaches the metal joint on the high potential side,
The phenomenon of short circuit was confirmed in another experiment. Therefore, in order to prevent a short circuit, it is necessary to prevent the growth of copper oxide along the insulating tube, and the growth can be prevented by using the metal joint having the tip portion shown in FIG.

[Embodiment 2] In order to investigate the effect of preventing corrosion products from adhering to the insulating pipe, the cooling water circulating device described in Embodiment 1 was used to form a tapered tip as shown in FIG. The metal joint and the conventional metal joint shown in FIG. 6 were tested under the same conditions.

As a result of the experiment, the conventional metal joint (low potential side)
Deposits were observed at the tip of the, and they had grown along the insulating tube. On the other hand, in the metal joint (low potential side) shown in FIG. 2, it was observed that the tip portion was the electric field concentration portion and therefore the adhesion was concentrated, but it did not grow along the insulating tube. .

By the way, in the metal joint shown in FIG. 2 used in the experiment, the length of the tapered tip portion is X2 = 0.5 mm, Y
It was 2 = 2 mm. Therefore, the longer the length X2, the farther from the insulating tube, so that the growth of the deposit can be prevented if the length X2 is at least 0.5 mm. Further, the length Y1 must be made longer as the electric field strength increases, but under the experimental conditions of the first embodiment, if Y2 = 2 mm at least, the growth of deposits can be prevented.

[0044]

As described above, according to the present invention, by providing the adhesion preventing means for preventing the adhesion of the dirt to the insulating tube, the withstand voltage of the insulating tube does not decrease and the short circuit is prevented. can do. As a result, high reliability can be ensured even if a high voltage is applied to the metal joint pipe of the water-cooled electric device, or even if the insulation pipe becomes shorter as the water-cooled electric device becomes smaller and has higher performance.

Further, when the adhesion preventing means is the stepped tip, the stepped tip is separated from the insulating tube, so that dirt does not grow along the insulating tube. Therefore, the withstand voltage of the insulating tube does not decrease and a short circuit can be prevented.

Furthermore, when the adhesion preventing means is a tapered tip, the tapered tip is separated from the insulating tube and has an electric field concentration shape, so that dirt is more likely to be concentrated and adhered to the tapered tip. , Dirt does not grow along the insulation tube. Therefore, the withstand voltage of the insulating tube does not decrease and a short circuit can be prevented.

Further, when the flowing water passage is provided at the stepped tip portion or the tapered tip portion, the dirt component is not concentrated at the tip portion of the metal joint, and the dirt can be prevented from adhering to the insulating pipe. Therefore, the withstand voltage of the insulating tube does not decrease and a short circuit can be prevented.

Furthermore, when the adhesion preventing means is a non-conductive member, it is possible to suppress the growth of dirt along the insulating tube. Therefore, the withstand voltage of the insulating tube does not decrease and a short circuit can be prevented.

[Brief description of drawings]

FIG. 1 is a main-portion cross-sectional view showing a metal joint in a water-cooled electric device that is Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view of essential parts showing a metal joint in a water-cooled electric device which is Embodiment 2 of the present invention.

FIG. 3 is a cross-sectional view of essential parts showing a metal joint in a water-cooled electric device which is Embodiment 3 of the present invention.

FIG. 4 is a cross-sectional view of essential parts showing a metal joint in a water-cooled electric device that is a reference example of the present invention.

FIG. 5 is a diagram showing an overall configuration of a conventional water-cooled electric device.

FIG. 6 is a view showing a conventional metal joint.

[Explanation of symbols]

1 pump, 2 heat exchanger, 3 ion exchange resin tower, 4
Cooling water pipe, 5 Water treatment pipe, 6 Flow control valve, 7
Electric equipment, 8 Insulation pipe, 8a Insulation pipe end, 9 Metal fitting, 10 Storage tank, 11 Piping, 13 Annular groove, 14 Stepped tip, 15 Tapered tip, 15a
Taper cut surface, 16 tip, 17 running water channel, 18
Cooling water between the insulating pipe and the tip of the metal joint, 19 Fitting part,
20 non-conductive member, 21 inner side of tip of metal joint, X
1, X2 Length between the insulating pipe and the tip of the metal joint (perpendicular to the longitudinal direction of the insulating pipe), Y1, Y2 Length of the tip of the metal joint (longitudinal direction of the insulating pipe), W Cooling water.

─────────────────────────────────────────────────── (72) Inventor Nobuyoshi Takahashi 2-3-3 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Co., Ltd. (72) Inventor Kenichi Mori 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric (56) References JP-A-8-83991 (JP, A) JP-A-7-253189 (JP, A) JP-A-63-96394 (JP, A) JP-B-49-26362 (JP, A) B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02K 9/00-9/28 H05K 7/20 F16L 1/00-1/04 F16L 5/00-7/00 F16L 57/00 -58/18

Claims (4)

(57) [Claims] 1. A water cooling system in which at least a circulation pump, a heat exchanger, and a storage tank for cooling water are piped to an object to be cooled through an insulating pipe, and a potential difference is generated between metal joints connected to both ends of the insulating pipe. Type electric equipment, wherein a metal joint on the low potential side is provided with an adhesion preventing means for preventing adhesion of dirt to the insulating pipe , and the adhesion preventing hand.
The step is a fitting portion of the metal joint inserted in the insulating pipe.
Step of the metal joint, which forms an annular groove on the outer peripheral surface of the tip of the
In addition to being the tip, the tip surface of the stepped tip is
Water-cooled electrical equipment, wherein vertical der Rukoto to the longitudinal direction of the edge line. Wherein said stepped distal portion to the insulating tube and the water-cooled electric spillway is provided according to claim 1 for preventing stagnation of cooling water between the stepped distal portion of the metal fitting machine. 3. At least a circulation pump, a heat exchanger, and
Cooling water storage tank is cooled by an insulating pipe
Between metal joints that are connected to both ends of the insulating pipe
A water-cooled electric device with a potential difference between
The metal joint on the side is to prevent dirt from adhering to the insulation pipe.
Is provided with adhesion prevention means because, and the said anti-adhesive means, to form a taper-cut surface on the tip outer peripheral surface of the fitting portion of the metal fitting which is inserted into the insulating tube, the tapered tip end of the metal fitting Water-cooled electric equipment characterized by being a part. 4. The water-cooled electric device according to claim 3 , wherein the tapered tip portion is provided with a running water passage for preventing retention of cooling water between the insulating pipe and the tapered tip portion of the metal joint.