JP3687241B2 - Water sealing device and water wheel provided with the water sealing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water sealing device and a water wheel provided with the water sealing device .
[0002]
[Prior art]
A recent high-head water turbine sealing device has a water supply groove in the circumferential direction on the sliding surface of the packing, and a water supply hole that communicates with the back pressure in the water supply groove to balance the sliding surface and the back pressure. A plurality of pressure balance type segment seals are used. This back pressure balance type segment seal has a simple water-sealing structure in which the divided packing is ligated to the sleeve by a garter spring.
[0003]
Japanese Patent Application Laid-Open No. 58-70063 discloses a sealed structure in which a plurality of back pressure balanced segment seals are stacked. Here, although the case where the number of the circumferential water supply grooves provided on the sliding surface is two is shown, the number of the circumferential water supply grooves is determined by the thickness of the packing. In a sealed structure in which a plurality of back pressure balanced segment seals are stacked, the opening area of each stage is the same, and the pressure difference is designed to be substantially equal.
[0004]
However, due to the difference in the water film thickness formed on the packing sliding surface of each stage, a phenomenon in which the pressure difference does not become equal occurs during the experiment, and the sliding surface pressure of the packing increases at the stage where the pressure difference is large. A phenomenon was observed in which the packing temperature was increased and the packing temperature became unstable.
[0005]
On the other hand, when the packing is thin, there is one circumferential water supply groove, which is provided in the central portion in the thickness direction. Therefore, a water supply hole (not shown) communicating with the water supply groove is also provided in the radial direction of the central portion in the thickness direction.
[0006]
The splitly arranged packing is ligated to the sleeve by a garter spring. When the packing is thin, the position in the thickness direction of the water supply hole communicating with the water supply groove overlaps with the garter spring. As a result, the entrance area of the water supply hole is reduced and the amount of water supply is reduced. Moreover, in the long-term use, the entrance area of the water supply hole is suddenly reduced due to algae or the like, and the water supply becomes insufficient. For this reason, the packing does not balance with the back pressure, the sliding surface becomes in a poorly lubricated state, and stable sliding characteristics may not be obtained.
[0007]
[Problems to be solved by the invention]
In this way, in a sealed structure in which back pressure balanced segment seals are stacked in multiple stages, a phenomenon in which the packing sliding surface pressure increases due to an unbalanced pressure difference and the packing temperature becomes unstable is observed. Dynamic characteristics may not be obtained. On the other hand, if the packing is thin, the amount of water supplied to the sliding surface will decrease, the sliding surface will be in a poorly lubricated state, and it may not be cooled sufficiently and stable sliding characteristics may not be obtained. is there. That is, in the case of the above-described sealed structure, stable sliding characteristics cannot be obtained for a long time due to an increase in sliding surface pressure due to an imbalance in pressure difference or insufficient supply of water to the water supply groove.
[0008]
An object of the present invention, to balance the pressure differential, or by reliably row TURMERIC the water supply to the water supply groove is to realize a seal water device which can obtain a stable sliding characteristics.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is characterized in that a sleeve is fixed to a main shaft, an arc-shaped packing disposed at an outer peripheral position of the sleeve, and a garter spring that constantly presses the packing toward the center of the main shaft. And an outlet opening area constituted by an outer peripheral side of the sleeve, an inner peripheral side of the packing case, and the arc-shaped packing Is that the upper part of the atmosphere side is the largest.
Another feature of the present invention, the sleeve is fixed to the main shaft, an arcuate packing disposed on the outer periphery position of the sleeve, a garter spring that always presses the packing towards the center of the spindle, these In the case where a plurality of sealing devices each having a stored packing case are stacked, the opening area of the outlet portion formed by the outer peripheral side of the sleeve, the inner peripheral side of the packing case, and the arc-shaped packing is set on the atmosphere side. The upper stage is the largest, and the means for increasing the amount of water supplied to the sliding surface of the arc-shaped packing is configured.
[0010]
The means for increasing the amount of water supply to the sliding surface is that the cross-sectional shape of the water supply hole is made non-uniform, the vertical groove provided on the sliding surface, or the surface that contacts the garter spring of the packing. It is good to comprise in either of the provided vertical groove.
Further, the water sealing device having the above characteristics is particularly effective when applied to a water turbine.
[0011]
That is, in the case of the shaft seal device formed in this way, the gap area formed by the outer peripheral side of the sleeve on the outlet side of each step, the inner peripheral side of the packing case, and the arc-shaped packing is made different in each step, so that the pressure difference Can be equalized. For this reason, since the pressing force of the arc-shaped packing in each step is the same, stable sliding characteristics can be obtained.
[0012]
On the other hand, the shaft seal device formed in this way increases the amount of water supplied to the sliding surface of the arc-shaped packing, improves the lubricity and cooling of the sliding surface, and provides stable sliding characteristics. .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a longitudinal sectional view showing a first embodiment of a water-sealing device according to the present invention, and FIG. 2 is a view showing a circumferential arrangement state of arc-shaped packings. A water sealing device 10 shown in FIG. 1 is a device that prevents fluid from leaking from the gap between the main shaft 1 and the turbine cover 11. The water sealing device 10 has a sleeve 2 fixed to the main shaft 1, and the sleeve 2. A sealing device provided with an arc-shaped packing 5 arranged at the outer peripheral position of the garnet, a garter spring 6 that constantly presses the packing 5 toward the center of the main shaft 1, and packing cases 8, 8a, 8b that house these. Are stacked in three stages. Here, the case where the sealing device has a three-stage structure will be described, but the number of sealing device stages is determined by the sealing pressure and is not particularly limited. The packing 5 is provided with a circumferential water supply groove 3 on the sliding surface, and the water supply groove 3 is provided with a water supply hole 4 communicating with the back pressure. The contact surface of the water supply hole 4 with the garter spring 6 is a conical processing surface 4a. In the three-stage structure, the upper, middle, and lower stages are called in order from the top. The packing material is carbon with good lubricity in the upper and middle stages, and resin with excellent earth and sand wear resistance is used in the lower stage.
[0014]
A supply hole 9 is provided between the lower and middle packings to supply fresh water so as to prevent mixing of earth and sand into the sliding surface and to cool the sliding surface. The water-sealing mechanism seals the river water sediment that flows into the water-sealing device with the lower-stage resin packing, and seals the water in the middle and upper tiers to reduce the amount of water leakage. .
[0015]
With the structure in which the water sealing devices are stacked in three stages, the gap areas constituted by the sleeve outer periphery side, the packing case inner periphery side, and the arc-shaped packing 5 of each stage outlet are made different at each stage.
[0016]
The total clearance area at the exit of each stage is calculated by the following formula.
[0017]
[Expression 1]
G = L × (a, b, c) × n (Expression 1)
Where L: circumferential distance between packings a: radial gap at upper outlet b: radial gap at middle outlet c: radial gap at lower outlet n: number of packing G: total gap area at each outlet Since the circumferential distance L between the packings and the number of packings n are the same in each step, the radial gaps (a, b, c) at the outlets of each step are changed, and the total clearance area of each step outlet is made different. (See FIG. 2). The magnitude relationship between a, b, and c is a> b ≧ c. The reason for making c the smallest is to prevent river water containing foreign matter from entering the water supply side as much as possible. Moreover, the arrow in the figure indicates the direction in which the fluid flows. The fresh water supply pressure is usually set about 1 kg / cm ² higher than the lower sealed water pressure.
[0018]
In the sealing device configured in this manner, fresh water enters through the supply hole 9 and is supplied in the lower and middle stages. Shimizu that entered the middle stage flows to the upper stage. Since the total gap area of the upper stage outlet is larger than the total gap area of the middle stage outlet, the amount of water leaked from the upper stage to the atmosphere is greater than the quantity of water leaked from the middle stage to the upper stage. As a result, even if the water film thickness formed on the sliding surface of the middle packing as in the prior art becomes thicker than the upper stage, the back pressure Pa of the upper stage does not increase because of water leakage, and stable sliding characteristics Is obtained.
[0019]
According to the experimental results, when the ratio of the total clearance area of the middle outlet and the total clearance area of the upper outlet is set in the range of 0.6 to 0.8, the differential pressure (Pb-Pa) between the middle and upper And the atmospheric differential pressure (Pa-Po), and the differential pressure is equalized.
[0020]
In this sealing device, as a means for increasing the amount of water supplied to the sliding surface of the arc-shaped packing, the contact surface of the water supply hole 4 with the garter spring 6 is a conical processing surface 4a. As a result, the inlet of the water supply hole 4 is not blocked by the garter spring, the amount of water supplied to the packing sliding surface is increased, and the packing sliding surface is balanced with the back pressure (Pa, Pb). Coolability is improved and stable sliding characteristics can be obtained.
[0021]
FIG. 2 is a view showing the arrangement of the packing 5 in the circumferential direction. The gap area G between the packings 5 can be as many as the number of packings. The gap area G is calculated by Equation 1. The gap area G can also be changed by making the circumferential distance L between the packings different at each stage. Further, by making the number of the arc-shaped packings 5 different in each stage, the circumferential distance L between the packings changes as a result, so that the gap area G can be made different.
[0022]
FIG. 3 is a first embodiment of the water sealing device according to the present invention shown in FIG. 1 and explains the shape of the upper arc-shaped packing 5. The arcuate packing 5 has a packing shape in which chamfers 5a are provided at both ends. Such a sealing device is configured by arranging packing having chamfered portions 5a at both ends in the upper stage and packing without chamfering in both ends of the packing in the middle stage. In this case, the amount of water leakage from the chamfered portions 5a provided at both end portions is larger than that in the middle stage, and therefore, the relationship between the exit portion radial gaps at each stage may be a = b> c. Further, chamfering the corner portion of the packing greatly prevents breakage at the corner portion and improves handling.
[0023]
FIG. 4 shows a second embodiment of the shaft seal device according to the present invention.
[0024]
In this embodiment, the difference from the first embodiment is that the water supply means for the water supply groove 3 provided on the packing sliding surface is provided with a vertical groove 4b on each stage entrance side so as to communicate with the water supply groove 3. In the point. The depth of the longitudinal groove is substantially equal to the depth of the water supply groove 3. This is so considered that the packing can be used until the water supply groove 3 disappears when the wear progresses.
[0025]
According to this embodiment, basically the same effect as the first embodiment can be obtained, and the sleeve 2 is cooled by the longitudinal groove 4b, so that the cooling performance of the sliding surface is improved. However, the allowable back pressure can be increased, and as a result, the packing thickness can be reduced. When the packing thickness is reduced, the height of the sealing device is lowered in a structure in which a plurality of stages are stacked, and the cost can be reduced. Furthermore, since the position of the sealing device can be brought closer to the runner side, the length of the main shaft can be shortened, leading to cost reduction.
[0026]
FIG. 5 shows a third embodiment of the shaft seal device according to the present invention.
[0027]
In this embodiment, the difference from the first embodiment is that the water supply means for the water supply groove 3 provided on the packing sliding surface is communicated with the water supply hole 4 at the contact portion with the garter spring on the outer peripheral side of the packing. The longitudinal groove 4c is provided. The shape of the vertical groove 4c is not particularly limited as long as it can reliably supply water to the water supply hole.
[0028]
According to this embodiment, basically the same effects as those of the first embodiment described above can be obtained, and since the vertical groove 4c faces downward, sludge or the like is difficult to enter the water supply hole. Damage to the moving surface is prevented. As a result, the life of the packing can be extended.
[0029]
FIG. 6 shows a fourth embodiment of the shaft seal device according to the present invention.
[0030]
In this embodiment, the difference from the first embodiment is that the water supply means for the water supply groove 3 provided on the packing sliding surface is communicated with the water supply hole 4 at the contact portion with the garter spring on the outer peripheral side of the packing. The longitudinal groove 4d is provided. The shape of the vertical groove 4d is not particularly limited as long as water can be reliably supplied to the water supply hole.
[0031]
According to this embodiment, basically the same effects as those of the first embodiment described above can be obtained, and the vertical groove 4d is opened in the vertical direction, so that the flow velocity at the inlet of the water supply hole is very high. This prevents the entry of foreign matter and the like. As a result, the life of the packing can be extended.
[0032]
Next, the case where the water-sealing device of the present invention is applied to a water wheel will be described. That is, as shown in FIG. 7, the water turbine has a main shaft 1, a runner 41 fixed to the lower portion of the main shaft 1, and an upper portion of the runner 41. The water wheel cover 11 includes the water sealing device of this embodiment. ing. The water sealing device 10 includes a sleeve 2 and a packing case 8. The water sealing device 10 attached to the water turbine cover 11 is of the embodiment shown in FIG.
[0033]
According to the embodiment, the same operational effects as the second to fourth embodiments can be basically obtained such that the differential pressure can be equalized and the amount of water supplied to the sliding surface is increased.
[0034]
In addition, it is possible to provide a water turbine that can be stably operated for a long time.
[0035]
【The invention's effect】
According to the present invention, in the water sealing device configured as described above, the gap area constituted by the sleeve outer peripheral side, the packing case inner peripheral side, and the arc-shaped packing at each step outlet side is made different at each step. Thus, the pressure difference can be equalized. For this reason, since the pressing force of the arc-shaped packing in each step is the same, stable sliding characteristics can be obtained. On the other hand, the shaft seal device formed in this way increases the amount of water supplied to the sliding surface of the arc-shaped packing, improves the lubricity and cooling of the sliding surface, and provides stable sliding characteristics. .
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a first embodiment of a water-sealing device according to the present invention.
FIG. 2 is an explanatory view showing the arrangement of packings in the circumferential direction.
FIG. 3 is an explanatory view showing the chamfered state of both ends of the packing.
FIG. 4 is a longitudinal sectional view showing a second embodiment of the water sealing apparatus according to the present invention.
FIG. 5 is a longitudinal sectional view showing a third embodiment of the water-sealing device according to the present invention.
FIG. 6 is a longitudinal sectional view showing a fourth embodiment of the water-sealing device according to the present invention.
FIG. 7 is a longitudinal sectional view showing a water wheel to which a water sealing device according to the present invention is applied.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Main shaft, 2 ... Sleeve, 3 ... Water supply groove, 4 ... Water supply hole, 5 ... Packing, 6 ... Garter spring, 7 ... Upper cover, 4a ... Conical processing surface, 8, 8a, 8b ... Packing case, 9 ... Supply Hole, 10 ... Sealing device, 11 ... Water wheel cover, Pa, Pb, Pc ... Each stage back pressure.

Claims (4)

  A seal having an arc-shaped packing disposed on the outer peripheral position of the sleeve, a garter spring that constantly presses the packing toward the center of the main shaft, and a packing case that stores them. In the case where a plurality of water devices are stacked, the opening area of the outlet portion constituted by the outer peripheral side of the sleeve, the inner peripheral side of the packing case and the arc-shaped packing is maximized in the upper stage on the atmosphere side. Water sealing device.   A seal having an arc-shaped packing disposed on the outer peripheral position of the sleeve, a garter spring that constantly presses the packing toward the center of the main shaft, and a packing case that stores them. In the case where the water device is stacked in a plurality of stages, the opening area of the outlet formed by the outer peripheral side of the sleeve, the inner peripheral side of the packing case, and the arc-shaped packing is maximized in the upper stage on the atmosphere side, and the arc-shaped A sealing device characterized by comprising means for increasing the amount of water supplied to the sliding surface of the packing. The means for increasing the amount of water supplied to the sliding surface according to claim 2 , wherein the water supply hole has a non-uniform cross-sectional shape, a vertical groove provided on the sliding surface, or the garter spring of the packing A water sealing device comprising a longitudinal groove provided on a surface in contact with the water. A water wheel comprising the water sealing device according to claim 1 .

Images