US1688736A

US1688736A - Hydraulic turbine

Info

Publication number: US1688736A
Application number: US175665A
Authority: US
Inventors: Lewis F Moody
Original assignee: Individual
Current assignee: Individual
Priority date: 1927-03-16
Filing date: 1927-03-16
Publication date: 1928-10-23
Anticipated expiration: 1945-10-23

Description

Patented Oct. 23, 1928.

LEWIS F. MOODY, F PHILADELPHIA, PENNSYLVANIA.

iYnnAULrc 'rURBINn Application tiled March i6, 1927.y Serial No. 175,665. i'

This invention relates to means for sealing the wicket or pivot gates of a hydraulic turbine and certainrobjects of my invention are to provide a simple and inexpensive arrangement and one which will be efficient in operation.

A further object is to have an improved arrangement which is particularly applicable for sealing the space between the Wicket gates and distributor plates. Other objects are to provide an arrangement whereby a substantially minimum length of sea-ling means for this space may be used and to provide a substantially continuous seal around the entire circumference of'the gate mechanism when the gates are closed, this arrangement having the sealing means held in a fixed position in a stationary part of the turbine.

Another object is to have means adaptedv not only to seal the' vertical overlapping portions of the wicket gates but which will also form an element of an improved combination of elements including the gate operating mechanism, whereby it is possible to reduce to a minimum or eliminate abnormal stresses not only in the turbine structure but also in the sealing means. Still another object is to have sealing means of such a nature as to be suitable not only for effectively resisting abrasive action by foreign material which might be present in the fluid fiow, but will also automatically prevent creation of certain abnormal stresses which might otherwise be caused by irregularities either in the initial form of the parts or due to wear thereof.l

Other objects and advantages will appear from the following description of the accompanying drawings, in which:

Fig. l is a partial vertical section of a turbine having wicket gates with my improved sealing means associated therewith.

Fig. 2 is a reduced elevation of the turbine showing the gate operating mechanism applied to two for clearness.

Fig. 3 is a fragmentary plan view taken on line 3 3 of Fig. 1 and showing the gates in closed position.

Fig. 4 is a fragmentary vertical section showing the gate adjacent the upper distributor plate and taken on a transverse line indicated by line 4-4 of Fig. 2, only'one gate being shown for simplicity.

Fig. 5 is a sectional view similar to that of Fig. Il but showing a modified manner of segates, other gates being omitted curing the sealing means in the distributor plate.

Fig. 6 is a partial perspective view of the distributor plate and sealing means combined therewith. i

` Fig. 7 is an enlarged transverse section of the sealing mem-ber.l

Fig. Sis a view similar to Fig. 3 but showing a modified arrangement ofthe sealing means. I

Fig. 9 is a further modified arrangement of the sealing means. I

In the illustrated embodiment of the invention, there is conventionally shown in Fig. 1 a fragmentary portion of a hydraulic turbine having a runner or rotor l. Fluid flows thereto through a usual intake passage 2 and is controlled by a series of wicket or pivot gates 3, these gates having upper and lower pivot shafts 3a ournaled in upper and

lower distributor plates

5 and 6 respectively. The upper pivot shafts extend through the distributor plate and have arms A lfixed thereto and adapted for connection to a suitable operatin'g mechanism including a shifting ring S and operating links L, Fig. 2, whereby all gates will be simultaneously moved to open or closed position. In order that the gates may operate freely, clearance between the ends of each gate and the distributor plates is provided and heretofore leakage has occurred through this clearance space when the gates are in their closed position. In my invention I prevent this leakage by providing' an improved arrangement which is not only economical in construction and maintenance but is efficient in operation. The arrangement includes a sealing ring or "strip t, preferably of rubber or other resilient material, embedded in suitable grooves 8 formed in the upper and lower distributor plates. These grooves may have vertical sides or the sides may be inclined to form a dovetail groove. The sealing strip is preferably cemented in place, although other suitable means can be used, such as vulcanizing or by holding through friction and pressure.

The preferred location of the sealing ring with respect tothe gates is such that not only is the economical construction had, but also substantially continuous sealing action is had around the whole circumference of the gates. As shown in Fig. 3 the grooves are circular, having their center of curvature at the runner axis so that they may be easily machined out during other turning operations on the distributor rings. Moreover, it is preferable that these grooves be disposed at a radial distance from the axis approximately equal to the radius of the point of contact between successive vaneswhich, with the usual form of vanes, will be slightly inside the axes of the pivot shafts it being noted that by such an arrangement the vanos, when in their closed position, will engagel each `other at a point directly above the sealing ring, thus effecting sealing action along the entire areabetween any two adjacent pivot shafts. Furthermore, by having the grooves ass through the vopenings for the pivot sha ts, a well finished ter'- minal is made for the end of each rubber seg ment constituting the sealing ring.

A further advantage of havin the sealing ring stationary is that when t e gates are opened a small amount they are freed from contact on the Greater portion of their top and bottom surfaces, so that the work to be done by the gate operating cylinders and the necessary governor capacity are kept relatively small. Moreover, every time the gates are opened pressure on the rubber is released, and each time they are closed the gates will slightly compress the rubber, thus varying its compression and tending to preserve its resiliency. Uncovering of the sealing rings when the gates are open also permits access to be readily had thereto for either replacenient o'r inspection. Suitable clearance is provided adjacent the upper and lower ends of each vane by tapering away the distributor plate, as at 9, and further clearance is also provided due to crowning the sealing ring, as'sliown in Fig. 7. Crowning of the sealing ring performs the further function of permitting smooth flow thereover without causing eddy currents or the like. Moreover, by

making the sealing ring of rubber, abrasive action thereon or on the upper and lower surfaces of the guide vanes, which might be caused b sand or other foreign matter in the flow, is reduced to a minimum.

As shown in Fig. 4 the sealing ring is held in position by a suitable keeper ring 10 having suitable means such as screws or bolts securing it to the distributor plate. The keeper ring forms one side of the sealing strip groove, the opposite side thereof being either inclined to provide a dovetail groove for the sealing rinor or said sides may be straight. On the ot er hand, if itis desired not to use al keeper ring. a construction such as shown in Fig. 5 can be used, wherein the opposite walls of the groove 8 are fixed.

Should it be desired to prevent possible leakage immediately around the pivot shafts, the arrangement shown in Fig. 8 could be used. Here it will be noted that the groove S is disposed inside the pivot shafts so that a continuous and unbroken groove and sealing strip is provided. In this case the gates may be sli litly enlarged or offset adjacent the pivot slgiafts so as to4 overlap the rubber strip when in vclosed position.

In some constructions it may be convenient to provide straight grooves such as shown at 8b in' Fig. 9 instead of circular grooves. The grooves, due to terminating in the' ivot shaft openings 12, can be readily mil ed out or otherwise machined. In all of the forms shown, however, it will be understood that the manner of holding the rubber seal may be that shownin Figs. 4 or 5 or the straight sided rooves may be used.

In oth the preferred and modified arrangement of sealing strips the portion of the strip between adjacent pivot shafts will be common to adjacent vanes. Hence the common portion of the sealing strip is simulother and thereby reduce harmful strains which might otherwise be set up in tlie strip.

Leakage has heretofore occurred principally through the clearance space between the gate ends and distributor plates so that the sealing means at this area will in most instances be sufficient for all practical purposes. The regions where the ates Contact with each other are usually mac ined to provide tight contact between them. However, under certain conditions it ma be desired to prevent all possible leakage. 9 do this, I have combined with the sealing rings for the gate ends further means for sealing the vertical overlapping portion of the gates when in their closed position. A s shown in Fig. 3, a strip 14, preferably of rubber, but which could be of other readily yieldable and preferably resilient material, is disposed in a vertical groove formed in a side of each vane adjacent the tip of the preceding vane when in closed position. The groove may be formed in the various ways pointed out in connection with the distributor grooves an'd the strip may likewise be held and also, have its surface crowned similar to that shown in Fig. 7. Due to the resilient character of the rubber, not only will a tight seal be effected, but also any irregularities in the surface of the gates will be readily conformed to by the rubber. Moreover, if one vane should not be uite true, or should any of the operating lin vs, pins, or the like, become worn so that all vaiies will not engage each other simultaneously the resilient rubber seal will automatically yield, so that there will not be induced in the operating mechanism undue local strains. M resilient 'means not only permits abnorma o'r irregular conditions to be taken care of, but also any variations in fio such A*conditions `willa'lsobe taken care of automatically as they arise. To take care of such conditions, it has heretofore been customary, in certain instances, to use adjustable` linkage orthelike in the operating mechanism. j In other instances, it has been proposed to prevent leakage and take careiof same result of securing a close fit is accom` plished by u sing machined surfaces. In these respects my invention departs radically therefrom, for I use material of a resilient character and this resiliency would not of course permit the prior permanent eflect to be had.

A Moreover, the previously mentioned results which I attain, due to using resilient means, produce new'results not obtainable with the prior permanent effect.

In another'aspect of the invention involving broadly a "v ertical seal, I find it advantageous to actuate-the pivot gates through the pivot shafts `as previously described in distinction to VAthose prior art arrangements wherein the gates are actuated by applying an operating force to one corner of the gate,

for -in` my mode of operation it is possiblel not only to have the sealing action efliciently createdfand'maintained but also to reduce or 'eliminate the possibility of abnormal stresses being set up in the operating mechanism and sealing strip. The results due to my combinationl can be enlarged by further using a vertical strip having the resilient characteristic. f'

- volves an important feature of operation. In

many large and important plants it is necessary frequently to close the turbinegates and to leave some or all of the units idle for considerable periods, but to have them in condition for quickly taking up the load. In some plants the units must be shut down for a portion of eachday, during the times of 10W load demands, water being stored in the pond or reservoir during this period for use at times of peak load. Any leakage through the turbine while shut down represents a loss of power which-may aggregate a substantial loss of earning capacity. When it is attempted to minimize this loss by providing very small mechanical clearances at the top and bottom of tlie'wicket gates, Where the bulk of the leakage usuallyl` occurs, there is danger of the gates becoming jammed due to slight distortions *of the powerhouse structure or due to sand or griti'n' the water; and rapid wear is likely to occur. Moreover, small clearances ation and call for greater governor capacity.

.By the use oflthisv iiiventionthe gates are pressure, with .the aid of fluidipressure, when the gates are closed the hollow portion may have communication with the intake passage on the upstream side of the gates, as by suitable ports or passages also shown in Fig. 7 If desired the passages leading to the hollow portion may be omitted thereby providing a closedinterior space filled for example only with air. Also the sealing strips may be provided with a core of material more resilient than the surrounding portion, this making a strip which is solid and thus similar to the solid strip shown in Fig. 5.

I claim:

l. The combination with a turbine having pivoted gates and stationary members adjacent the ends thereof, of means for sealing the space adjacent to and extending a sub- 'stantial distance along said gate ends includported therein, of means for sealing the space adjacent said gate ends including a rubber sealing strip carried by one of said stationary members, and adaptedto be engaged by the end surface of the gates when in their closed position and to be disengaged and uncovered when said gates'are in their open position. 1

3. The combination with a. hydraulic turbine having stationary members forming an entrance passage and gates pivotally supported therein, of means for sealing an end of each of said gates including a rubber sealing" strip carried by one of said stationary members, and adapted to be engaged by the end surface of the gates when in their closed position and to be disengaged and uncovered when said gates are in their open position, and said rubber strip having its sealing surface crowned, thereby to provide a substantially continuous surface at the juncture of the rubber strip and stationary member.

.4. In combination with a hydraulic turbine having means forming an entrance passage and gates pivotally disposed therein and adapted to have overlapping relation with respect to each other when in their closed position, of means for sealing the space adjacent the gate ends including a common sealing strip adapted to be engaged by a pluralit of said gates.

5. In com mation with a hydraulic turbine havingmeans forming an entrance passage and gates pivotall disposed therein and adapted to have over apping relation with respect to each other when 1n their closed position, of means for sealing the space adjacent the gate ends vincluding a common sealing strip adapted to be engaged by a plurality of said gates, and so arranged with respect thereto that a substantlall continu- -ous sealing Contact is had along t e circumtion, of means for sealing the space adjacent the gate ends including a common sealing strip adapted to be engaged by a plurality of said gates and so arranged with respect thereto that a part of the stri disposed between adjacent gates is engaged y the entrance portion of one gate and by the discharge portion of the adjacent gate.

7. In combination with a hydraulic turbine having means forming an entrance assage and pivoted gates disposed therein, o means, for effecting a seal between said means and gates including a sealing strip adapted to be commonly engaged by adjacent gates and so arranged with respect thereto that during movement of said gates said strip is subjected to substantially opposin frictional forces.

8. In combination witg a hydraulic turbine having means forming an entrance passage and wicket gates havmg pivot shaftsjournaled in said means, of means for eiecting a seal adjacent the ate ends .when said gates are in their closed position, com rising an arcuate sealing strip extending su sta-ntially the circumferential length of each gate.

9. In combination with a hydraulic turbine having means forming an entrance passage and wicket gates having pivot shafts journaled in said means, of means for eii'ecting a seal adjacent the are'in their close position, comprising an arcuate stationary sealing strip extending between the pivots of adjacent gates and offset from the axes thereof whereby said strip is engaged substantially along its entire length between the adjacent pivots.

10. In combination with a hydraulic turbine having means forming an entrance passage and wicket gates having pivot shafts journaled in said means, of means for effecting a seal adjacent Ithe gate endswhen said gates are in their closed position, comprising a circular groove intersecting the pivot shaft bearings and being concentric to the turbine ate ends when said gates ends of said 1,ass,7se

sage inclu ing upper and lower removable` distributor plates provided with offset surfaces and openings for receiving pivot shafts,\

and wicket. ates having shafts pivotally disposed in sai openings, of means for effecting a seal between said distributor plates and the atcs comprising a circular groove formed 1n each plate and intersecting said openings, and a rubber scaling strip disposed Within said grooves for engagement with the end surfaces of each gate.

12. In combination, a hydraulic turbine having stationary means forming anentrance passage, a series of wicket gates pivotally disposed therein and having circumferential overlapping relation with respect to eachl other, means for operating said gates including a pivot shaft extending from each gate through said stationary means, means for subjecting said pivot shafts to a torsional operating force, and sealing means interposed between thc overlapping portions of adjacent gates. Y

13. In combination, a hydraulic turbine having means orming an entrance passage including a stationary member, wicket gates disposed in said passage and having overlapping portions, and means for operating said gates including pivot shafts extendin through said stationary member and adapted to be simultaneously subjected to a torsional operating force to effect operation of said gates, and resilient sealing means vertically interposed between the overlapping portion of said gates.

14. In combination, a hydraulic turbine having means forming an entrance passage and wicket gates pivotally disposed therein and having overlappin relation with respect to each other when in t eir closed position, a rubber sealing strip vertically interposed between the overlapping portions of adjacent gates and so positioned that the tip of one gate enga-ges said stri to eiect a sealing action, and means carrled by'said entrance forming means for sealing the wicket gate ends, both of said means bein so relatively disposed as to cooperate to e ect a substantially complete seal.

15. In combination, a hydraulic turbine having means forming an entrance passa and wicket gates pivotally disposed therein and havin overlapping relation with respect to each ot er, of means for sealing the ends of said gates, and means vertically disposed over said other sealing means when saidl gates are closed for sealing the overlapping portion of adjacent gates.

16.3. In combination, a hydraulic turbine having means forming an entrance passage and wicket gates pivotally disposed therein and having overlapping relation With respect to each other, of means for sealing the ends of said gates, and vertically disposed means for sealing the overlapping portion of adjacent gates, said vertical sealing means having its ends terminate adjacent to said other sealing means.

17. In combination, a hydraulic turbine having means forming an entrance passage and Wicket gates pivotally disposed therein and ha ving overlapping relation with respect to each other, of means for sealing the ends of said gates, and vertically disposed means for sealing the overlapping portion of adjacent gates, both of said sealing means comprising resilient rubber whereby they may yield automatically to irregularities and thereby reduce abnormal stresses to a minimum.

18. The combination with a turbine having pivoted gates and stationary members adjacent'the ends thereof, of resilient sealing means carried by said stationary members and adapted to engage said gates when in their closed position. y

19. In a hydraulic turbine, the combination comprising means forming an entrance passage, gates pivotally disposed therein and having overlapping relation with respect to each other when in their closed position, and resilient means for sealing the space adjacent the gate ends including a common sealing strip engageable by a plurality of said gates.

LEWIS F. MOODY.