JPS6043737B2 - 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 rotary machine that circulates a coolant around a rotor to cool the rotor, and particularly to a coolant inlet/output device thereof.

As is well known, increasing the capacity of a rotating electric machine depends on 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 electric machine is determined by its temperature rise, that is, its cooling performance. On the other hand, it is becoming 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 therein, but it is now possible to develop this idea and successfully circulate the coolant to the rotor. If this is possible, the cooling effect can be dramatically increased. However, in the case of a turbine generator, the rotor usually rotates at a high speed of 3,600 revolutions (60 Hz).
The biggest problem in realizing such a high-speed rotating body is how to introduce and extract the coolant into the high-speed rotating body, and this has hindered the spread of liquid-cooled rotor-type rotating electric machines.

FIG. 1 is a diagram showing a conventionally considered coolant inlet/output device for a liquid-cooled rotor, and 1 is an inlet pipe to which a cooling liquid 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 the rotor coil, so if water containing impurities is used as the coolant, the impurities may cause corrosion of the tubes and rotor coil. Therefore, it is desirable to use pure water that does not contain any impurities. 2
is a circular inflow pipe which has an opening 2a and receives the cooling liquid from the inlet pipe 1 through this opening, 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 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 six fittings) 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 between the inflow pipes 2 and 3 to integrally connect them, and also serves to reinforce both pipes 2 and 3. It also serves as Inflow pipe 2 having this protruding piece 2c
and the outflow pipe 3 are firmly and integrally connected, for example, by shrink fitting or the like, and constitute a supply/discharge pipe 4. 4a is a flange formed at the end of this supply/discharge pipe 4, and 5 is a flange 5 that is in close contact with this flange and is connected, for example, with 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, the 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. The cooling liquid sent from the rotor coil circulates through the rotor coil and then is discharged to the outflow passage 5c. Note that the arrows in the figure indicate the flow of the coolant, and after circulating and cooling the rotor coil as described above, the coolant is discharged from the opening 3a of the outflow pipe 3 via 5c and 3b. . Reference numeral 61 designates an upstream outlet chamber, that is, a first outlet chamber, for receiving the discharged liquid from the opening 3a, and in order to prevent the coolant (pure water) from coming into contact with the atmosphere and being contaminated, is configured to maintain a full state.

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 flow pipe does not come into contact with the atmosphere and is not contaminated, so after lowering the temperature using a heat exchanger (not shown), etc. is fed again to the inlet pipe 1 via a feed pump (not shown),
Subject to recirculation.

81 is a first labyrinth seal for preventing the cooling liquid from leaking from inside the inlet pipe 1 to the eleventh outlet chamber 61;
Since it is impossible to completely eliminate leakage between the rotating part and the fixed part, efforts are made to minimize leakage.

This leakage is not a big problem because it is circulated again through the first outlet pipe 71 as described above, but if the leakage amount is too large, the efficiency will be poor, so it is desirable to have a small amount. Not even. 82 is the first outlet chamber 6
1 and the rotating supply/discharge pipe 4 to suppress leakage.
The labyrinth seal 62 is an intermediate outlet chamber, ie, a second outlet chamber, which receives leakage from the first outlet chamber 61 that has passed through the second labyrinth seal.

Unlike the first outlet chamber 61, this second outlet chamber 62 is not filled with cold liquid, and therefore there is a risk that the coolant (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 weak gas such as nitrogen or hydrogen to the second outlet chamber 62 through this supply pipe, the air inside the second outlet chamber 62 is The pressure 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 the same as the coolant drawn out from the first outlet chamber 61. Similarly, it is provided for recirculation via a heat exchanger and a feed pump (none of which are shown). 83 is a third labyrinth seal for suppressing the leakage of the above-mentioned cold gas from between the second outlet chamber 62 and the rotating supply/discharge pipe 4; The tip of the water supply pipe 83a to which the sealing liquid is sent by a supply means (not shown) is open, and the sealing liquid having a pressure slightly higher than that of the cold gas is supplied from the water supply pipe 83a, and this pressure difference As a result, the cold gas is sealed in the second outlet chamber 62.

A part of this sealing liquid passes through the labyrinth seal 83c and flows into the second outlet chamber 62, but as described above, the cooling liquid led out from the second outlet pipe 72 is not purified. Since it is recirculated, this sealing fluid, like the cooling fluid, must be pure water. 63 is a downstream outlet chamber, ie, a third outlet chamber, which receives the sealing liquid that has passed through the labyrinth seal 83b, and 73 is a third outlet pipe communicating with this third outlet chamber.

The third outlet chamber 63 is not insulated from the atmosphere, and the sealing liquid leaking into the third outlet chamber 63 is therefore contaminated with the atmosphere and is therefore discarded without being recycled. Of course, it is also possible to send the water to a reprocessing device, purify it, and recirculate it. As described above, the sealing liquid (pure water) leaking into the third outlet chamber 63 is discarded or reprocessed, so in order to downsize the pure water production device or reprocessing device, it is necessary to It is necessary to suppress the amount of sealing liquid (pure water) leaking into the chamber 63 as much as possible. Third outlet chamber 6 of conventional third seal 83
Since the seal 83b located on the third side was a labyrinth seal, it was necessary to increase the length of the seal portion in order to suppress the amount of sealing liquid leaking into the third outlet chamber 63.

Incidentally, the rotor shaft 5 is supported by a bearing (not shown), but as is clear from the figure, the supply/discharge pipe 4 cannot be provided with a bearing due to the outlet chamber, etc., so there is an overhang on the rotor shaft 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.

This axial runout is more likely to occur as the supply/discharge pipe 4 becomes longer, so the shorter it is, the better. However, in the conventional device described above, when trying to improve the sealing effect, the third seal becomes longer, and the supply/discharge pipe 4 This had the disadvantage that the shaft had to be made longer, increasing the risk of shaft runout. This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and the seal 83b located on the third outlet chamber 63 side of the third seal 83 can be provided with sufficient effect with a short seal length. It is an object of the present invention to provide a coolant lead-in/out device which is compact, has a small amount of leakage of the sealing liquid into the third outlet chamber 63, and has a small shaft vibration.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 shows an enlarged view of a third improved seal. 83
Reference numeral 1a denotes a supply hole for sealing liquid (pure water), from which sealing liquid whose pressure is slightly higher than that of the weak gas in the second outlet chamber 62 is supplied.

831b is a labyrinth seal for suppressing leakage of the sealing liquid into the second outlet chamber 62.

This leakage liquid can be recirculated as it is because the second outlet chamber 62 is filled with a permeable gas and is not contaminated by the atmosphere, so some leakage is acceptable, and furthermore, the pressure difference between the sealing liquid and the permeable gas is Due to its small size, the 831b uses a labyrinth seal which has a simple structure and high reliability.

4b faces a screw stationary surface 832a provided on the outer periphery of the supply/discharge pipe 4 in a direction opposite to the rotational direction, and its pumping effect prevents the sealing liquid from leaking into the third outlet chamber 63 during rotation. do.

833b is an annular rubber that surrounds the outer periphery of the supply/discharge pipe 4, and an air supply pipe 833a is configured to open on the outer circumferential side to supply compressed gas and is attached to the annular rubber holding member. By supplying compressed gas from the annular rubber 833b, it is possible to press the annular rubber 833b onto the outer peripheral surface of the supply/discharge pipe or to oppose the supply/discharge pipe with a small gap.

In the seal of the present invention described above, when the seal is at rest, the annular comb 833b is crimped onto the outer circumferential surface of the supply/discharge pipe to prevent leakage of the sealing liquid to the third outlet chamber 63, and the screw seal pump During low-speed rotation, when the effect is poor, the gap between the annular rubber 833b and the outer circumferential surface of the supply/discharge pipe is kept small to prevent leakage of the third sealing fluid (to the third outlet chamber 63), and during high-speed rotation, the gap between the annular rubber 833b and the outer peripheral surface of the supply/discharge pipe is kept small, and during high-speed rotation, the screw 4b
The pumping effect of the stationary surface 832a suppresses leakage of the sealing liquid to the third outlet chamber 63. That is, leakage of the sealing liquid into the third outlet chamber 63 can be suppressed to an extremely small amount over the entire range from stoppage to high-speed rotation.

Furthermore, since the seal of the present invention is a non-contact type and has a certain degree of freedom in the axial positional relationship between the rotating surface and the stationary surface,
Another great advantage is that it is less affected by vibrations in supply and exhaust pipes and axial thermal expansion.

As described above, according to the present invention, a combination of a seal using a screw pump effect and an annular rubber seal with a variable gap is used as a seal for suppressing leakage of sealing liquid into a chamber filled with the atmosphere. The short seal length makes it possible to suppress the leakage of the sealing liquid to a minimum, and the length of the supply/discharge pipe can also be shortened, which has the effect of reducing shaft vibration. In the above embodiment, the comb ring 833b is used as a means to prevent leakage of the sealing liquid when the rotation of the supply/discharge pipe stops, but it is also possible to use a stretchable synthetic resin instead of the rubber ring to achieve the same effect. I can do it.

In the above-mentioned embodiment, the present invention is applied to a case where there are three output chambers, but it can be similarly applied to a case where there are two outlet chambers as shown in FIG. That is, the fourth
In the figure, 612 is an upstream outlet chamber that integrates the outlet chambers 61 and 62 in FIG. 1, and 712 is this upstream outlet chamber 6.
An outlet pipe 9 communicating with the air supply pipe 9 is an air supply pipe similar to that shown in FIG. By always maintaining the pressure inside 612 at a value slightly higher than atmospheric pressure, contamination of the coolant due to contact with the atmosphere is prevented. That is, the two outlet chambers 61 and 62 in FIG. 1 are combined into one, and the outlet pipe 7
The coolant drawn out from 12 is provided for recirculation as in FIG. Further, although the above embodiment shows the case where pure water is used as the cooling liquid, it goes without saying that other liquids than pure water may be used as long as they do not corrode the tubes and the rotor coil.

Furthermore, in the above embodiments, the present invention has been described 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 types of rotating electric machines, if necessary.

Further, in the embodiment described above, labyrinth seals are used as the seals 81 and 82 for suppressing leakage of the coolant, but it goes without saying that other seals such as mechanical seals 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 line This is for explaining another application example. Note that the same symbols in each figure indicate the same or corresponding parts, 1 is the inlet pipe, 2 is the inflow pipe, 2a is the opening thereof,
2b is an inflow passage, 2c is a protruding piece, 3 is an outflow pipe, 3a is an opening thereof, 3b is an outflow passage, 4 is a supply/discharge pipe, 4a is a flange, and 4b is machined on its outer peripheral surface in the opposite direction of rotation. 5 is the rotor shaft, 5a is the flange thereof, 5a is the inlet passage, 5c is the outlet passage, 61, 612 is the upstream outlet chamber, 6
2 is an intermediate outlet chamber, 63 is a downstream outlet chamber, 71, 72, 7
3,712 is the outlet pipe, 81, 82, 83, 84, 831
b is a labyrinth seal, 9,833a is an air supply pipe, 83a
, 831a is a sealing liquid supply pipe, 832a is a stationary surface, 833
b indicates a rubber ring.

Claims (1)

[Claims] 1. A supply/discharge pipe connected to the rotor shaft of a rotating electric machine that introduces and discharges a coolant to the rotor shaft, and a coolant discharged from the supply/discharge pipe provided with a gap around the outer periphery of the supply/discharge pipe. An upstream outlet chamber is filled with a shielding gas having a pressure higher than atmospheric pressure and is discharged to the outside.An upstream outlet chamber is provided in the axial direction of this upstream outlet chamber to receive leaked cooling liquid from the upstream outlet chamber and communicates with the atmosphere. a downstream outlet chamber, a supply hole for supplying sealing liquid to the gap at the end of the downstream outlet chamber on the upstream outlet chamber side;
A screw is provided on the outer periphery of the supply/discharge pipe so as to pressurize the sealing liquid toward the upstream outlet chamber, and a screw is provided surrounding the outer periphery of the supply/discharge pipe to stop rotation of the supply/discharge pipe. A coolant inlet/output device for a liquid-cooled rotor-type rotating electrical machine, comprising an extensible member that is in close contact with the supply/discharge pipe to prevent leakage of the sealing liquid to a downstream outlet chamber.