JPS6037691B2 - 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 rotating electric machine, the problem is how to suppress 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 single machine capacity of generators among rotating electric machines, especially turbine generators, from the viewpoint of improving 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).
(and how to derive this) is the biggest problem for realization, and this has hindered the spread of liquid rotor type rotating electric machines.

FIG. 1 is a diagram showing a conventionally considered coolant inlet/output device for a liquid rotor, and 1 is an inlet pipe into which a coolant, such as pure water, is supplied via a feed pump (not shown). It is.

The reason why pure water is used as a cooling liquid is as follows. The coolant is circulated within each tube and the rotor coil as described below, so if water containing impurities is used as the coolant, the impurities may cause the inside of each tube and the rotor coil to deteriorate. Therefore, it is desirable to use pure water that does not contain any impurities. Reference numeral 2 designates a circular inflow pipe which has an opening 2a and receives the cooling liquid from the inlet pipe 1 through this entrance, and its 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 path for the coolant.

3a is a closing part provided at one end of this outflow pipe 3;
Coolant is discharged through this barrier.

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. This serves as a base for integrally connecting the inflow pipe 2 and the outflow pipe 3, and also serves as reinforcement for both pipes 2 and 3. The inflow pipe 2 and the outflow pipe 3 having the protruding piece 2c are firmly connected together, for example, by shrink fitting or the like, thereby forming a supply pipe 4. 4a is a flange formed at the end of this supply pipe 4, and 5 is a flange 5a that closely fits this flange and is connected with, for example, bolts (not shown).
This is a rotor shaft of a rotating electric machine having a rotor shaft, and needless to say, a rotor coil (not shown) is attached to this rotor 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 outflow path 3b of the feed E pipe 4, respectively. After the coolant is circulated through the rotating precoil, 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 channels 5c and 3b. Ru. Reference numeral 61 designates a first outlet chamber for receiving the liquid discharged from the closed portion 3a, and the chamber is always kept full of cooling liquid to prevent the cooling liquid (pure water) from coming into contact with the atmosphere and being contaminated. It is configured as follows.

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 efficiency will deteriorate, so it goes without saying that it is better to have a smaller amount. Nor. 82 is the first exit chamber 61
and the rotating feed pipe E pipe 4 to prevent leakage.
The labyrinth seal 62 is a second outlet chamber that receives leakage from the first outlet chamber 61 that has passed through the second labyrinth seal.

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 feeding E pipe 4, and reference numeral 63 indicates a third labyrinth seal from the second outlet chamber 62 that has passed through the third labyrinth seal. 73 is a third outlet pipe adapted to be connected to this third outlet chamber.

The cooling liquid reaching the third outlet chamber 63 is connected to the two-stage seal 82,
Due to the effect of
Therefore, the coolant discharged from the third outlet pipe 73 is discarded without being recirculated. Of course, it is also possible to send the water directly to a reprocessing unit, perform water purification treatment, and then provide it for recirculation. The above device can achieve the intended purpose.

By the way, the rotor ball 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., so there is an overhang on the rotor ball 5. It will be supported in form. For this reason, the supply/discharge pipe 4 is always
subject to shaft runout problems. Axial runout is undesirable because it impairs the sealing effect. The longer the supply/discharge pipe 4 is, the more likely it is that this deflection will occur, so it is better to make it shorter, but in the above-mentioned follower device, there are three outlet chambers, so the supply/discharge pipe 4 must be made that much longer. , the risk of shaft runout increases. In addition, in the conventional device described above, the outlet chamber 61 is kept full of water, so the casing of the outlet chamber 61 must be tightly sealed. The problem was that it was large. 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 an exit chamber formed by integrating the exit chambers 61 and 62 in FIG. 1, and 712 is an exit pipe passed through this exit chamber,
The rest is the same as in FIG. The idea of FIG. 3 is that the outlet chamber 612 is not filled with water, and therefore, to avoid contact with the atmosphere, the outlet chamber 612 is supplied with nitrogen, hydrogen, etc. from the air supply pipe 9, and gas is supplied to the outlet chamber 612. The idea is to maintain the pressure inside 612 at a value higher than atmospheric pressure to prevent atmospheric intrusion. That is, the two outlet chambers 61 and 62 in FIG. 1 are combined into one, and the cooling liquid led out from the outlet pipe 712 is provided for recirculation as in FIG. 1. According to FIG. 3, the drawbacks of FIG. 1 can be avoided to some extent, but the following major problems remain. That problem is cavitation. That is, the closing part 3 of the outflow pipe 3
Since the pressure of the outlet chamber 612 that receives the simulated liquid from a is not as high as when it is full of water, the coolant is discharged without resistance). The pressure in the coolant pipe is lower than when the outlet chamber 612 is full. The second temperature of the coolant flowing through the outlet channels 3b, 5c and the coolant pipes such as the rotor coil is:
Since the rotor coil rises due to cooling, cavitation easily occurs when the pressure becomes low, leading to the erosion of surrounding members. In FIG. 1, the outlet chamber 61 that receives the drained liquid from the outflow pipe 3 is kept in a bran water state in order to prevent such cavitation from occurring. Therefore, it was considered to be an essential condition to keep the secondary outlet chamber full of water, and for this reason, the various drawbacks mentioned above were thought to be unavoidable. Now, by further developing the concept shown in FIG. 3 above, the device shown in FIG. 4 can be considered as a coolant lead-in/out device that can solve not only the various problems shown in FIG. 1 but also the problem of cavitation. Fourth
In the figure, reference numeral 10 denotes a discharge ring having a small hole 10a, which is fixed to the inlet pipe by, for example, a cold fit so that the small hole 10a faces the entrance part 3a. Therefore, the cooling liquid from the outlet pipe 3 is discharged into the outlet chamber 612 through the small hole 10a of the discharge ring 10. That is, the discharge ring 10 exhibits a so-called orifice action when discharging the coolant, 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. By solving the problem of cavitation, the exit chamber 612 is no longer necessary.
There is no need to keep the outlet chambers full of water, thus making it possible to reduce the number of outlet chambers to two. Therefore, the supply/discharge pipe 4
Since the length can be made shorter than that shown in Figure 1, the risk of shaft vibration can be reduced, and since the outlet chamber 6 is not filled with water,
When the 12 casings have a split structure, it is possible to easily seal the split surfaces, and to obtain a coolant lead-in/out device that can eliminate power loss due to friction with the supply/discharge pipe 4.
As mentioned above, the outlet chamber 612 is provided with a discharge ring 10 having an orifice 10a for drainage from the outlet pipe 3 to prevent cavitation within the outlet pipe 3.
This makes it possible to prevent the shaft from being filled with water, thereby achieving the effect of preventing shaft vibration by shortening the shaft length and reducing power loss in rotating parts. However, on the other hand, the waste water discharged from the outflow pipe 3 which is rotated at high speed through the orifice 10 is discharged from the outlet chamber 61.
As a result, a new problem arises in that the inner wall of the outlet chamber 612 is eroded and a large noise is generated. This invention prevents the outlet chamber from being submerged by providing a double lining on the inner wall of the casing of the outlet chamber 612, thereby preventing erosion of the outlet chamber casing and noise caused by collision of discharge from the rotor of a rotor-cooled rotating electric machine. This is to prevent

FIG. 5 is a cross-sectional structural diagram showing an embodiment of the present invention.

In the figure, 11 and 12 are inner plates supported by the casing, 11 is made of a hard material such as stainless steel or titanium, and 12 is made of a synthetic resin as soft as rubber, for example. The inner wall of the casing is protected by receiving the drainage water from the discharge ring IQ with the hard inner lining plate 11. The inner lining plate 11 is also gradually eroded by the collision of drainage water, but there is no problem if the inner lining plate is replaced periodically. The inner lining plate 12 softens the collision of drainage water and reduces noise. The inner panels 11 and 12 do not necessarily need to be provided on the entire inner wall of the outlet chamber 612, and a sufficient effect can be obtained if they are provided only on the portions where the drainage water collides with them.

As in Kamiaoki, this invention provides a first tube made of a soft material in an outlet chamber that receives the coolant discharged from the liquid cooling rotor.
Since the inner lining and the second inner lining made of a hard material are provided, erosion of the outlet chamber casing and generation of noise due to collision of the cooling liquid can be prevented.

Further, in the above embodiment, a case is shown in which pure water is used as the coolant, but it goes without saying that other liquids than pure water may be used as long as the liquid does not corrode the tubes and the rotor coil.

Furthermore, in the above embodiments, the present invention was explained as being applied to a generator, particularly a turbine generator, but it goes without saying that it can be applied to other generators such as a water turbine generator, as well as various rotating electric machines such as an electric motor, if necessary. do not have.

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 the drawing]

FIG. 1 is a diagram showing a conventional coolant inlet/output device, FIG. 2 is a sectional view taken along the line 0-0 in FIG. FIG. 4 is a diagram showing a lead-in/out device which is a further development of FIG. 3 and which can be considered before reaching the present invention, and FIG. 5 is a diagram showing an embodiment of the coolant lead-out device according to the present invention. In addition, the same reference numerals in each figure indicate the same or equivalent parts, 3 is the outflow pipe, 3a is the entrance part, 3b is the outflow path,
4 is a scale supply pipe, 5 is a rotor shaft, 5b is an inflow path, 5c is an outflow path, 61, 62, 63, 612 are outlet chambers, 71, 72,
Reference numerals 73 and 712 indicate an outlet pipe, a discharge ring, 11 an inner plate made of a hard material (second inner plate), and 12 an inner plate made of a soft material (first inner plate). . Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. A circular inflow pipe, an outflow pipe that surrounds this inflow pipe and forms an outflow path in a gap with the inflow pipe, and a plurality of small holes that communicate with the opening of this outflow pipe and are fitted into the inflow pipe. a supply/discharge pipe directly connected to the rotor shaft; and an outlet chamber provided surrounding the supply/discharge pipe to receive the coolant discharged from the outlet passage through the small hole. ,
A first inner lining made of a soft material and attached to the inner wall of the casing of the outlet chamber; and a second inner lining made of a hard material and attached to the first inner lining. Coolant inlet/output device for rotor-type rotating electric machines.