JPS585568A - Shaft sealing device of rotary electric machine - Google Patents

Abstract

PURPOSE:To enhance performance of the sealing device for a rotary electric machine by reducing thermal deformation of the seal ring by means of lessening of its temperature difference in the radial direction and by equalizing temperature rise and thermal deformation of each seal ring. CONSTITUTION:This shaft sealing device is so constituted that the gap between the seal casing 5 and the outside circumferential surfaces of seal rings 2, 3 is minimized, that a circumferential groove 14 with channel-shaped profile is in the neighborhood of and facing to the slide surfaces of each seal ring 2, 3, that oil lead-in grooves 15 for feed of the sealing oil to said circumferential groove 14 are arranged in the circumferential direction of each seal ring 2, 3, and that oiling holes 7 are provided in the casing 5 in the same number as and facing to the oil lead-in grooves 15. According to this constitution, the gap formed between the casing 5 and the outside circumferential surfaces of seal rings 2, 3 is so small as to bring about the stagnant condition to the sealing oil 6 in this space, which will provide an insulating effect to lessen temperature difference between the outside circumferential surfaces and the slide surfaces of seal rings 2, 3, and thus excessive thermal deformation is prevented. At the same time, oil supply through different oiling holes 7 is equalized to ensure uniform temperature in the slide surfaces.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shaft sealing device for a rotating electrical machine that seals internal gas in a rotating part of a turbine generator or the like.

Figures 1 and 2 show a shaft sealing device for sealing hydrogen gas inside a conventional turbine generator, in which a seal ring (2) on the hydrogen gas side is divided into several parts around the rotating shaft (1).
The seal ring (3) on the atmosphere side is pressed against the outer periphery by a ligature-like spring (4) and housed in the seal casing (5), and the seal oil 16) at a pressure higher than the internal pressure is supplied to one oil supply port. By refueling from (7), the hydrogen gas high pressure chamber (
8) and the atmospheric chamber (9) to prevent hydrogen gas from leaking into the atmosphere. The handle is the oil drainer, α0 is the main body frame, and (Lz is the drain pipe).

In such a device C2, the fluid loss that occurs between the seal ring (21, (31) and the rotating shaft +11 is small and the temperature rise is low, so the seal ring (
2), (3) Thermal deformation due to the temperature rise and temperature distribution C does not pose any particular problem. However, since the fluid loss increases in proportion to the square of the rotational speed C=2, the fluid loss suddenly increases when the rotational speed becomes high. For this reason, the seal rings (21, (3)) are made of bronze, nickel alloy, etc. and have a coefficient of linear expansion that is extremely large compared to the rotating shaft (1), so the seal rings (2) are made of bronze or nickel alloy as the temperature rises.

(3) and the rotating shaft (1) becomes larger, and the high pressure chamber (
8) and the amount of leaked oil to the atmospheric chamber (9) increases. Therefore, as shown in Figure 2, the flow velocity on the outer circumferential surface of seal rings +2) and (3) increases, and as shown in the temperature distribution diagram 0 (= the temperature on the outer circumferential surface is higher than the sliding surface of seal rings (21, (31). The difference is low and the temperature difference is large.Also, since there is only one oil filler port (7), the oil filler port (7) (closer to the second seal ring +2),
+3) The flow velocity on the outer peripheral surface is large and the cooling effect is good.

From the above, if high rotational speed ζ: seal ring (
2), +3), the temperature difference between the sliding surface and the outer circumferential surface becomes large, and the temperature difference is
Since the seal ring f21, (3) is divided into several parts, the seal ring f21, (3) is thermally deformed as shown by the one-dot chain line in FIG. 2, resulting in a complicated shape as a whole. This means that the gaps between the rotating shaft (1) and the seal rings (2), (31) become uneven, resulting in localized areas where the oil film thickness becomes thinner, and the seal rings (21, (3) and the rotating shaft (31) become uneven. There were drawbacks such as an increase in the amount of hydrogen gas leakage due to damage due to metal contact with 1) and rupture of the oil film due to load area C2, which deteriorated the sealing characteristics.

The present invention was made in view of the above drawbacks, and it improves the sealing characteristics by reducing the temperature difference in the radial direction of the seal rings to reduce thermal deformation, and by equalizing the temperature rise and thermal deformation of each seal ring. It is an object of the present invention to provide an excellent shaft sealing device for a rotating electrical machine. In FIGS. 3 and 4, parts having the same functions as those in FIGS. 1 and 2 are designated by the same reference numerals, and their explanations will be omitted. The gap between the outer peripheral surface of the seal rings f2+, +3) and the seal casing (5) is made as small as possible, and each seal ring (
21, a circumferential groove (14) with a U-shaped cross section is provided facing the sliding surface of (31), and a seal oil (6) is provided in the circumferential groove 0.
) is provided in the circumferential direction of each seal ring +2>, +3. Further, the same number of oil filler ports (7) as the introduction grooves (a) are arranged in the seal casing (5) so as to face each other in the introduction grooves (15).

The following C action will be explained. Since the gap between the seal casing (5) and the outer peripheral surface of the seal ring f2) jf3) is small, the flow resistance of the seal oil (6) is large, and the seal oil 16) during this period is close to a stagnation state. This means seal oil (6)
Since the thermal conductivity of the seal ring is low, it provides a heat insulating effect, and the temperature difference between the sliding surface and the outer circumferential surface of the seal ring +2+ (3) becomes small and excessive thermal deformation is prevented. In addition, the amount of oil supplied from the oil supply port (7) to each seal ring (2), (31) is equalized, and the cooling effect of each seal ring f2), (3) is uniform, and the temperature of the sliding surface is equalized. .

In other words, even during high-speed rotation, the seal ring f2)
, (3) can be prevented, the gaps between the seal rings +2), +3) and the rotating shaft 11) are equalized, and the amount of discharged seal oil (6) is reduced. Therefore, the seal oil supply device can be downsized. Furthermore, since no significant thermal deformation occurs, the local oil film thickness can be reduced.

(3) Metallic contact between the rotating shaft (1) and the rotating shaft (1): Damage accidents caused by this can be prevented. Furthermore, the negative pressure generation area is reduced,
Reduce the amount of in-flight hydrogen gas leakage.

As described above, according to the present invention, in the shaft sealing device ζ2 of a rotating electric machine, each seal ring is provided with circumferential grooves facing each other close to the sliding surface, thereby reducing the gap between the outer peripheral surface and the seal casing. , an introduction groove that communicates with the circumferential groove is provided in the center of the outer circumferential surface, and opposing oil fill ports are provided in the seal casing, so thermal deformation of the seal ring is prevented and the amount of seal oil discharged is reduced. It has the excellent effect of significantly improving the sealing properties and improving the performance and reliability of rotating machinery.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing a conventional shaft sealing device for a rotating electric machine, FIG. 2 is a vertical cross-sectional view taken along line A-A and ii in FIG. 1, and FIG. 3 is a shaft sealing device for a rotating electric machine according to the present invention. FIG. 4 is a longitudinal sectional view taken along the line BB≦− in FIG. 3. (11...rotation axis (21, (31...
Seal ring (4)...Spring (5)...
... Seal casing (6) ... Seal oil
(7)...Fuel filler port I...Circumferential groove a8.
...Introduction Mizo Agent Patent Attorney Inoue - Male Figure 1 '' Figure 2 Figure 4

Claims (1)

[Claims] A shaft sealing device for a rotating electric machine that prevents leakage of high-pressure gas that is sealed inside the machine by supplying sealing oil to the rotary shaft (a seal ring that is divided into two parts is pressed by a garter-like spring from the outer circumference, and is housed in the case). 6-2, each of the seal rings has circumferential grooves facing each other close to the sliding surface to reduce the gap between the outer circumferential surface and the seal casing, and to reduce the gap between the outer circumferential surface and the seal casing;
A shaft sealing device for a rotating electrical machine, characterized in that an introduction groove communicating with the circumferential groove is provided, and the seal casing is provided with two opposing oil supply ports of the same number.