JPS6038939B2 - Coolant inlet/output device for liquid-cooled rotor-type rotating electric machines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid-cooled rotor-type rotating electric machine that circulates a coolant around a rotor to cool the rotor, and particularly to a coolant introduction/intake device thereof.

As is well known, in order to increase the capacity of a single rotary electric machine, it is necessary to determine how to suppress the temperature rise, that is, how to achieve effective cooling.

In other words, it is no exaggeration to say that the capacity of a rotating electrical machine is determined by its temperature rise, that is, its cooling performance. On the other hand, it is increasingly necessary to increase the capacity of generators among rotating electric machines, especially turbine generators, in order to improve the efficiency of power plant construction. By the way, a cooling method that circulates hydrogen gas has been used to cool turbine generators so far, and an increase in the capacity of a single unit has been achieved, but this has already reached its limit. A significant increase in capacity cannot be expected. Therefore, there is a strong desire to put another cooling method into practical use. To meet this demand, it is conceivable to use a cooling fluid with good cooling efficiency, such as water, instead of hydrogen gas as the cooling medium. Based on this idea, it has already been proposed and realized to cool the stator by circulating the coolant, but if we can develop this and successfully circulate the coolant to the rotor. ,
The cooling effect can be dramatically increased. ．． However, if we take a turbine generator as an example, the rotor usually rotates at a high speed of 3,600 revolutions per minute (60Hz). Deriving this is the biggest problem for realization,
This has hindered the spread of liquid-cooled rotor-type rotating electric machines.

FIG. 1 is a diagram showing a coolant inlet/output device for a liquid-cooled rotor that has been considered as a subsidiary, and 1 is an inlet pipe to which coolant, such as pure water, is supplied via a feed pump (not shown). be.

The reason why pure water is used as a cooling liquid is as follows. As described below, the coolant is circulated within each tube and rotor coil, so if water containing impurities is used as the coolant, the impurities may cause each tube and rotor coil to become damaged. Therefore, it is desirable to use pure water that does not contain any impurities. 2 is a circular inflow pipe having an opening 2a and receiving the cooling liquid from the inlet pipe 1 through this opening;
The hollow interior 2b serves as an inflow path for the cooling liquid.

Reference numeral 3 denotes a circular outflow pipe provided around the inflow pipe 2 with a predetermined gap therebetween, and the gap 3b between the inflow pipe 2 and the inflow pipe 2 serves as an outflow pipe for the coolant.

3a is an opening □ provided at one end of this outflow pipe 3;
Coolant is discharged through this opening.

Incidentally, the outflow pipe 3 and the inflow pipe 2 are integrally connected to form a supply/discharge pipe 4 as shown in FIG. That is, in FIG. 2, 2c is a plurality of protruding pieces (the figure shows a case of six pieces) formed integrally with the outer periphery of the inflow pipe 2, and these protruding pieces 2c are connected to the outflow pipe 3. It acts as a spacer to integrally connect the inflow pipe 2 and the outflow pipe 3, and also serves to reinforce both pipes 2 and 3. The inflow pipe 2 and the outflow pipe 3 having the protruding piece 2c are firmly connected together by, for example, solid fit, and constitute a supply/discharge pipe 4. 4a is a flange formed at the end of this supply pipe 4, and 5 is a rotor shaft of a rotating electrical machine having a flange 5a that is in close contact with this flange and connected, for example, with bolts (not shown). Needless to say, a rotor coil (not shown) is attached to the child shaft.

Further, as is clear from the figure, this rotor shaft 5 is provided with an inflow path 5b and an outflow path 5c that communicate with the inflow path 2b and the outflow path 3b of the supply/discharge pipe 4, respectively, and the supply/discharge pipe 4 is provided with an inflow path 5b and an outflow path 5c. After the coolant is circulated through the rotor coil, it is discharged into the outflow passage 5c. Note that the arrows in the figure indicate the flow of the cooling fluid, and after the rotor coil is circulated and cooled as described above, it is discharged from the opening 3a of the outflow pipe 3 via the outflow passages 5c and 3b. Ru. 61 is this opening □
This is the first outlet chamber for receiving the discharged liquid from the section 3a, and is configured to always remain full of the cooling liquid to prevent the cooling liquid (pure water) from coming into contact with the atmosphere and being contaminated. ing.

71 is a first outlet chamber for discharging the cooling liquid from this first outlet chamber.
As mentioned above, the coolant drawn out from this first outlet pipe does not come into contact with the atmosphere and is not contaminated, so it is cooled by a heat exchanger (not shown) or the like before being sent. It is fed back to the inlet pipe 1 via a feed pump (not shown) and subjected to recirculation.

Reference numeral 81 denotes a first labyrinth seal for suppressing leakage of cooling liquid from inside the inlet pipe 1 to the first outlet chamber 61, and it is impossible to completely eliminate leakage between the rotating part and the fixed part. Therefore, efforts are made to minimize leakage.

This leakage is not a big problem because it is circulated again via the first outlet pipe 71 as described above, but if the leakage amount is too large, the effect will be poor, so it goes without saying that it is better to have a smaller amount. Nor. 82 is the first exit chamber 61
A second labyrinth seal 62 is used to suppress leakage between the rotating supply and discharge pipe 4, and 62 is a second outlet chamber that receives liquid leakage from the first outlet chamber 61 that has passed through the second labyrinth seal. It is.

This second outlet chamber 62 is different from the first outlet chamber 61 described above and is not filled with cooling liquid, so there is a risk that the cooling liquid (pure water) will come into contact with the atmosphere and be contaminated. Reference numeral 9 denotes an air supply pipe for preventing this, and by constantly supplying a gas such as nitrogen or hydrogen to the second outlet chamber 62 through this air supply pipe, the second outlet chamber 62 The pressure inside the chamber is always kept slightly higher than atmospheric pressure to prevent atmospheric air from entering the second outlet chamber.

Therefore, since the liquid leaking from the second outlet chamber 62 does not come into contact with the atmosphere and is not contaminated, the coolant drawn out from the second outlet pipe 72 is similar to the coolant drawn out from the first outlet chamber 61. It is subjected to recirculation via a heat exchanger and a feed pump (none of which are shown). Reference numeral 83 indicates a third labyrinth seal for suppressing leakage between the second outlet chamber 62 and the rotating feed E pipe 4, and reference numeral 63 indicates leakage from the second outlet chamber 62 that has passed through the third labyrinth seal. The third outlet chamber, 73, which receives the leakage liquid, is a third outlet pipe adapted to this third outlet chamber.

The cooling liquid reaching the third outlet chamber 63 is connected to the two-stage seal 82,
Since the amount is small due to the effect of 83, it is not evacuated to the atmosphere, and therefore the coolant discharged from the third outlet pipe 73 is discarded as it is without being subjected to recirculation. Of course, it is also possible to send the water to a reprocessing device, purify it, and recirculate it. The above device can achieve the intended purpose.

By the way, the rotor shaft 5 is supported by a bearing (not shown), but as is clear from the figure, the feed pipe 4 cannot be provided with a bearing due to the outlet chamber, etc. It will be supported in the form of a hang. For this reason, run-out of the E pipe 4 is always a problem. Axial runout is undesirable because it impairs the sealing effect. This shaft vibration is caused by the supply/discharge pipe 4
The longer E is, the more likely it is to occur, so a shorter E is better. However, the conventional device described above has three outlet chambers, and the feed pipe 4 has to be made that much longer, increasing the risk of shaft runout. become. Furthermore, in the conventional device described above, the exit chamber 61
Since the outlet chamber 61 is to be kept full of water, the casing of the outlet chamber 61 must be tightly sealed, and since the outlet chamber 61 is full of water, there is a large power loss due to friction between the water and the feed pipe E pipe 4, which is problematic. . In order to solve this problem, it is conceivable to have two outlet chambers as shown in FIG. 3 and not to fill either outlet chamber with water.

That is, in FIG. 3, 612 is the outlet chamber 6 in FIG.
1 and 62 are integrated, and 712 is an outlet pipe passed through the outlet chamber, and the other parts are the same as in FIG. 1.
The idea of FIG. 3 is that the outlet chamber 612 is not filled with water, and therefore, in order to avoid contact with the atmosphere, a gas such as nitrogen or hydrogen is supplied to the outlet chamber 612 from the air supply pipe 9.
The idea is to prevent atmospheric air from entering even if the pressure inside the exit chamber 612 is set higher than atmospheric pressure and maintained at that value. That is, the two outlet chambers 61 and 62 in FIG. 1 are combined into one, and the coolant discharged from the outlet pipe 712 is recirculated as in FIG. 1. According to this Figure 3, the first
Although the problems with the diagram can be avoided for the time being, the following major problems remain. The problem is capitation. In other words, the pressure in the outlet chamber 612 that receives the drained liquid from the opening 3a of the outflow pipe 3 is not as high as when it is full of water, so the coolant is discharged without resistance. The pressure in the coolant tubes, such as the child coil (not shown), will be lower than when the outlet chamber 612 is full. The temperature of the coolant flowing through the coolant pipes such as the outflow passages 3b and 5c and the rotor coil (not shown) is high due to the cooling of the rotor coil. Cavitation will occur and the area will be eroded. In Fig. 1, the outlet chamber 61 that receives the drained liquid from the outflow pipe 3 is kept full of water in order to prevent the above-mentioned cavitation, and therefore, conventionally, keeping the outlet chamber full of water is an indispensable condition. Therefore, the various difficulties mentioned above were thought to be unavoidable. This invention further develops the idea shown in FIG. 3 above, and attempts to obtain an ideal coolant inlet/output device that can solve not only the various difficulties shown in FIG. 1 but also the problem of cavitation. FIG. 4 shows an example of this.

In FIG. 4, it is a release ring with a small hole 10a,
The small hole 10a is fixed to the inflow pipe by, for example, a slip fit so that it faces the entrance part 3a. Therefore, the outflow pipe 3
The cooling liquid from the outlet chamber 612 will be discharged through the small hole 10a of the discharge ring 10 into the outlet chamber 612. i.e. release ring 1
When the cooling liquid is discharged, a so-called orifice action occurs, and the pressure in the opening 3a becomes higher than the pressure in the outlet chamber 612. For this reason, it is possible to reliably prevent cavitation, which became a problem in FIG. Having eliminated the cavitation problem, it is no longer necessary to keep the outlet chamber 612 full of water, and therefore the outlet chamber 612 is
It is possible to reduce the number of Therefore, the length of the supply/discharge pipe 4 can be made shorter than that shown in Fig. 1, reducing the risk of shaft vibration.
It is possible to obtain an ideal coolant lead-in/out device in which the sealing of the casing becomes easy and power loss due to friction with the supply/discharge pipe 4 can be eliminated. In the above embodiment, the small holes 10a provided in the release ring 101 are arranged in two rows in the circumferential direction, but they may be arranged in one row or in three or more rows.

In addition, in Fig. 4, the small holes 10a are inclined relative to each other.
This is to prevent the coolant discharged from 0a from colliding with each other and scattering, and from colliding with the casing of the outlet chamber 612 and corroding it, but if there is no fear of this, it is necessary to force it to tilt. There isn't. Also release ring 10
is fixed to the inflow pipe 2 by shrink fitting, but it may be fixed by other means, or conversely, it may be fixed to the outflow pipe 3. Further, in the above embodiment, the discharge ring 10 and the outflow pipe 3 are separate bodies, but they can also be formed integrally. Further, in the above embodiment, a case is shown in which pure water is used as the cooling liquid, but it goes without saying that any liquid other than pure water may be used as long as it does not corrode each tube and the rotor coil. Furthermore, in the above embodiments, the present invention has been explained as being applied to a generator, particularly a turbine generator, but it can be applied to various rotating electric machines such as electric motors as well as other generators such as water turbine generators, if necessary. Not even. Further, in the above embodiment, a labyrinth seal is used as a seal for suppressing leakage of the coolant, but it goes without saying that other seals such as a mechanical seal may be used.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional coolant lead-in/out device, FIG. 2 is a sectional view taken along the 0-RO line in FIG. 1, and FIG. 3 is a diagram showing a possible lead-in/out device before reaching this invention. FIG. 4 is a diagram showing an embodiment of the present invention. In each figure, the same reference numerals indicate the same or equivalent parts, 1 is the inlet pipe, 2 is the inlet pipe, 2a is the closing part,
2b is an inflow path, 2c is a protruding piece, 3 is an outflow pipe, 3a is its closing part, 3b is an outflow path, 4 is a supply/discharge pipe, 4a is its flange, 5 is a rotor shaft, and 5a is its flange. , 5b is an inflow, 5c is an outflow path, 61, 62, 63, 612 are outlet chambers, 71, 72, 73, 712 are outlet pipes, 81, 82
, 83 and 84 are labyrinth seals, 9 is an air supply pipe, 10 is a discharge ring, and 10a is a small hole. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. An inlet pipe for guiding the coolant, one end of which is connected to the rotor shaft;
A circular inflow pipe whose other end is open and which introduces the cooling liquid from the inlet pipe, which is arranged with a gap around the outer periphery of the inflow pipe, and whose one end that leads out the cooling liquid through the gap is connected to the rotor. A circular tubular outflow pipe connected to a shaft, an opening provided at the other end of the outflow pipe for discharging the coolant, a discharge ring having a small hole covering the opening, and the opening containing the discharge ring. a first outlet chamber affixed to said inlet tube surrounding said discharge ring and receiving cooling fluid discharged from said discharge ring;
a first outlet pipe that leads the cooling liquid in the outlet chamber to the outside; a first seal that prevents the cooling liquid from passing between one side of the first outlet chamber and the inflow pipe; and the first outlet. a second seal that prevents the cooling liquid from passing between the other side of the chamber and the outflow pipe; and the first seal that receives the cooling liquid that has passed through the second seal.
a second outlet chamber adjacent to the outlet chamber on one side, a second outlet pipe for leading out the cooling liquid in the second outlet chamber to the outside, and a connection between the other side of the second outlet chamber and the outflow pipe; a third seal that suppresses the passage of cooling liquid between the first outlet chamber and the first outlet chamber; A coolant inlet/output device for a liquid-cooled rotor-type rotating electric machine, characterized in that the coolant is drawn out without being filled with liquid.