US2088771A - Hydraulic machine - Google Patents

Description

Aug-3,1937. A. G. SMITH 2,088,771-

- HYDRAULIC MACHINE Filed Nov. 4, 1936 2 Sheets-Sheet l Elma/whom A. G. SMl-TH Aug. 3, 1937. A. G SMITH 7 2,088,771

HYDRAULIC MACHINE Filed Nov. 4, 1936 2 Sheets-Sheet 2 AG. SMITH Patented Aug. 3, 19 37 PATENT OFFICE HYDRAULIC MACHINE Arthur G. Smith, York, Pa., assignor to S. Morgan Smith Company, York, Pa., a corporation of Pennsylvania Application November 4, 1936, Serial No. 109,071

2 Claims.

This invention relates to hydraulic machines, such as hydraulic turbines, pumps and the like, and more particularly to the type of hydraulic machines having runners with movable or adjustable blades rotatably mounted therein.

The hubs of the runners of the above type of hydraulic machines are filled with oil iorlubrieating thetrunnions of the blades and the blade operating mechanism within the hubs.

Since there isa tendency for water to enter the runner hub through the joints between the trunnions of the blades and the hub and mix with the lubricating oil, it is necessary to provide means for keeping water out of the hub, and the present invention relates to means for sealing the joints between trunnions of the blades and the runner hub.

An object of the invention is to provide an improved packing element by which the joints between the blade trunnions and the hub of a runner having adjustable blades is sealed, so that lubricating oil within the hub is prevented from flowing outwardly. through the joints and water is prevented from entering the hub through the joints. a

Another object of the invention is to provide an improved packing element for hydraulic machines of the character mentioned, which is simple in construction, and reliable and exact in function under all conditions of service.

The inventionalso comprises certain new and useful improvements in the construction, arrangement and combination of the several parts of which it is composed, as will be hereinafter more fully described and claimed. I

In the accompanying drawings:- Figure 1 is an elevation, partly in section, of the hub of a hydraulic turbine runnerconstructed according to the present invention; and. i

Fig. 2 is an enlarged. section of the portionof the runner hub in which the trunnion of a blade is mounted, showing the packing element.

In an application for United States Letters Patent for Hydraulic turbine, filed-by TorleifNor bom, September 17, 1936, Serial'No. 101,321, there is shown an. improved construction for'mounting the trunnions of the runnerblades in the hub of a. hydraulic turbine runner of the adjustable blade type. v 1 j w In another application;.for United States Letters Patent for Hydraulic turbinaifiled by George A. Jessop and Torleif Norbom,,.A"ugust 22, 1935; Serial No. 37,349, now Patent No'. 2,070,601,. dated February 16, 1937,,there is shown-.means by which the lubricating oil, for the blade; operating mecha nism within the runner hub is maintained at a predetermined pressure.

Since the runner blades must be free to turn, obviously slight clearances must be provided between the inner ends of the blades and the adjacent surfaces of the hub.

Therefore, in order to seal the joints between the runner blades and the hub, suitable sealing or packing means must be provided, and this packing should be so constructed that it will prevent the escape of oil outwardly from the interior of the runner hub, as well as the seepage of water into the runner hub, since the presence of water in the hub tends to destroy the lubricating properties of the oil.

Even with the lubricating oil in the hub under a pressure sufficient to overbalance the pressure of the Water flowing through the turbine, water will enterathe runner hub, and during operation of hydraulic turbines of the type above referred to, it has been found that ordinary packing rings or elements constructed of the usual packing materials quickly deteriorate and cease to function properly. This is probably due to the fact that such packings do not possess sufficient strength to withstand the mechanical forces present in hydraulic turbines, especially those of the larger sizes. 7

Since the detail construction of the hydraulic turbine as a Whole is well known, and is. clearly shown in the above referred to application and patent, the accompanying drawings illustrate only the hub of the runner.

Referring to the drawings, the runner comprises ahollow hub 23 which is fixed to the lower end of a hollow or tubular shaft 24.

A suitable number of blades 25 are rotatably supported in the hub 23 and project radially therefrom.

Theinner end of each blade 25 is formed with a trunnion 26, composed of an outer portion 21, intermediate portions 28, 29 and 3!], and an inner portion 3|.

The outer trunnionportion 21 is formed with an annular recess or groove 32 for the reception of a band 33, preferably formed from suitable hard non-corrosive metal, such as what is now known as stainless steel.

The trunnion portion 28 is mounted in a bushing 34 carried by a removable bearing 35 to be hereinafter more fully described.

Mounted on the trunnion portion 29 is an armor lever 36 of the blade operating mechanism.

The inner end portion 3! of the trunnion is iii mounted in a bearing 31 carried by the hub 23, and encircling the portion 30 of the trunnion is a thrust collar 38.

Means are provided for simultaneously rotating all of the blades 25 and for maintaining them in equal angular relationship, such means comprising an operating rod 46 mounted within the hollow shaft 24- of the turbine.

Fixed to thelower end of the rod 40 is a cross head 4!, which is connected by links 42 to the arms or levers 36 heretofore referred to.

The rod 45 extends upwardly through the hollow shaft 26 and is adapted to be operated by suitable mechanism (not shown), such for instance as that shown in United States Patent No. 1,937,772, granted December 5, 1933 to Daniel J. McCormack, for Hydraulic turbine.

Movement of the above referred tooperating mechanism is transmitted by rod 40 to the cross head 4|, and from said cross head such movement will be transmitted by the links 42 and levers 36 to the trunnions of the runner blades 25, thereby effecting an adjustment or change in position of 'said blades.

The bearing 35 is formed of an annular casting having a main or central portion made comparatively thick in cross section for the reception-of the bushing 34.

The bushing 34 is coextensive With the thick central portion of the bearing 35, and the inner end of said bushing is formed with an outwardly extending flange 46 which is disposed between the inner wall of the bearing 35 and the front wall of the lever 36.

During the operation of the machine, rotation of the runner 23 causes considerable end thrusts to be imparted to the trunnions of the blades 25. These end thrusts are taken up by the collars'38 and the flanged portions 46 of the bushings 34.

Since the hub of the runner is hollow and is filled with a suitable lubricating oil, friction will be reduced to a minimum between the outer walls of the levers 36 and the flanges 46, so that the levers 36 will operate freely.

The periphery of the bearing 35 is mounted in an annular recess or depression 56 formed around an opening 5! in the hub for each trunnion 26.

The bearing 35 is detachably fixed in the hub by means of a plurality of tap bolts 53.

- The outer face of the bearing 35 is formed with an outwardly projecting annular rib 55. This rib is substantially the same breadth as the breadth of the band 33 heretofore referred to, said rib being spaced a suitable distance from the exterior of said band to provide a channel or slot 56 between the bearing 35 and the adjacent portion of the runner blade trunnion 26.

Between the axial center of the trunnion 26 and band 33, the trunnion is formed with an annular recess or depression 51. This depression is disposed in the inner face of the portion of the trunnion 26 between the parts 2'! and 28 thereof.

.The central thickened portion of the bearing 35 is formed with an outwardly-projecting-annular boss 58 which is correspondingly formed'to the recess or-depression 51 so that when the bearing is mounted, on the trunnion the boss 58 will be disposed in the recess or depression 51. However, since the trunnion 26 moves relatively with respect to the bearing 35 during the operation of the machine, a slight space is provided between the adjacent faces of the trunnion Z6 and the bearing, as clearly shown in Fig. 2.

A suitable packing is mounted in the channel or slot 56 for the purpose of sealing the joint between the trunnion 26 and the bearing 35.

As shown in Fig. 2, the packing comprises, in the instant case, two sets of packing elements, each set including a plurality of packing rings GI, 62 of V-sections which are known as chevron packings. These twosets of packing elements are arranged in the channel or slot 56 in spaced relation to each other with the apexes of the packing rings 6|, 62 facing each other. That is to say, the apexes of the inner V-shaped packing rings 6| point outwardly, while the apexes of the outer V-shaped packing rings 62 point inwardly.

The stacked rings or chevron packings 6| are disposed between two annular supporting members 63, 64, of complementary V-shape which are mounted in the channel or slot 56 with the supporting member 63 at the inner end of said channel.

The stacked rings or chevron packings 62 are likewise disposed between two annular supporting members 65, 66 of complementary V-shape, the member 65 abutting the supporting member 64 and the member 66 being disposed in the outer portion of the channel 56.

The packing rings 6|, 62 are preferably formed of suitable flexible material, such as leather, rubber composition material, or any other such material known for the purpose, while the members 63, 64, 65 and 66 are preferably constructed of some suitable metal, or other non-flexible material.

For the purpose of retaining the packing elements in place and also for the purpose of enclosing the tap bolts 53 and the outer portion of the bearing 35, a sealing ring 6'! is utilized. This sealing ring is detachably connected to the bearing 35 by means of tap bolts 63 which are mounted in the heads of the tap bolts 53.

Since there is a considerable depression or pocket between the outer peripheral portion of the bearing 35 and the outer surface of the hub 23, the periphery of the ring 61 is formed with an inwardly projecting flange 69 which snugly fits within the outer wall 10 of the depression or recess 50. The inner edge of the flange 69 bears against the outer peripheral portion of the bearing 35, the joint therebetween being sealed by means of an annular rubber gasket H, as shown in Fig. 2.

The outer face of the ring 61 is shaped to conform with the contour of the exterior of the hub.

The portion of the ring 61 which surrounds the blade trunnion 26 is formed with an inwardly extending flange 12.

The flange 12 bears against the supporting member 66 of the packing elements and thereby provides means for retaining the packing elements in position within the channel 56. Due to the fact that the packing rings BI, 62 are formed of flexible material, the pressure exerted against the packings by the flange 12 of the ring 61 compresses said packing rings so that the packing rings are under tension. This results in the portions of the packing rings which bear against the band.33 being always maintained in contact withsaid" band so that the joint between the trunnion 26"and the bearing 35 is effectively sealed.

Due tothe skeleton construction of the ring 61, a chamber or space 13 is formed between the outer wall of said ring and the bearing 35. Therefore, in order that any water which may collect in the chamber may drain therefrom, the ring 61 is formed, at suitable intervals therearound, with openings 14.

As shown in Fig. 1, it will be noted that the inner portions of the blades 25 extend over the ring 51. Accordingly, so that the ring 61 can be assembled on to the hub 23 and removed therefrom without dismantling the blade from the hub, the ring 61 can be made in sections, instead of being constructed in one piece. A sectional ring and the manner in which it is assembled and disassembled is described in United States Patent No. 1,866,580 for a Sealing device, granted July 12, 1932 to Carlos Schmitthenner. Since the ring 61 corresponds substantially to the sealing ring of this patent, it has been deemed unnecessary in the instant case to further describe the construction thereof. However, it should be understood that the type of packing shown in the above mentioned Schmitthenner patent is entirely different in purpose than the packing elements of the present invention.

The chevron packing rings 6| function to prevent leakage of oil in the hub 23 outwardly through the joints between the trunnions 26 and the bearings 35, and the outer packing rings 62 are adapted to prevent water from passing inwardly of the hub. Due to the wedging action produced by the supporting members 63, 64, and also due to the disposition of the V-shaped packing rings 6!, the pressure of the oil outwardly against said packing rings tends to spread said rings tightly against the band 33 and the adjacent wall of the rib 55, and consequently the sealing action of the rings 6| is increased.

Likewise, due to the disposition of the V-shaped packing rings 62 and the wedging action of their associated supporting members 65, 66, the inward pressure of the water against said packing rings tends to spread the rings 62 outwardly, thereby increasing the sealing action thereof.

Therefore, from the foregoing it will be noted that I have provided an improved duplex packing which is adapted to so function that one portion of the packing effectively seals the oil within the hub of the runner, while the other portion of the packing, in functioning independently of the oil sealing packing, is adapted to prevent the seepage of water into the runner hub.

Having thus described my invention, what I claim is:

1. A runner of the type described comprising a hub, a plurality of adjustable blades having trunnions extending into said hub, outer and inner bearings for said trunnions mounted in the hub, an annular rib formed on each outer bearing in spaced relation to each trunnion to provide a channel between said bearing and said trunnion, a packing element comprising a plurality of stacked V-shaped rings. mounted in the inner portion of said channel, a second packing element similar to the inner packing element mounted in the outer portion of said channel, the apexes of the rings of said two packing elements facing each other with the outer edges of said packing rings engaging the longitudinal side walls of said channel, supporting members disposed on opposite sides of each set of said packing rings, and an annular element encircling the blade trunnion and detachably mounted in the hub and having an inwardly projecting flange formed on its inner periphery and engaging the outer supporting member for retaining the packing elements in the channel.

2. A hydraulic turbine runner comprising a hollow hub adapted to be filled with lubricating oil, a plurality of adjustable blades, each having a trunnion extending into said hub, a bearing for said trunnion mounted in the outer wall of said hub, an annular rib formed on said bearing and projecting outwardly therefrom, said rib encircling the trunnion and terminating at a point within the outer surface of the hub to form a channel between said bearing and said trunnion, a pair of similarly formed packing elements mounted in the inner and outer portions of said channel, each packing element comprising a plurality of stacked V-shaped flexible rings, said packing elements being oppositely disposed, the inner packing element engaging the trunnion to prevent leakage of oil outwardly from the hub and the outer packing element engaging the trunnion to prevent seepage of water inwardly of the hub, an annular element encircling the blade trunnion and detachably mounted in the hub and having an inwardly projecting flange for engaging said packing elements to expand the same, whereby the outer edges of the V-shaped rings of said packing'elements are maintained on one side in engagement with the exterior of the trunnion and on the opposite side in engagement with the longitudinal Wall of the channel, a chamber formed between the outer peripheral portion of said annular element and said bearing for receiving water seeping inwardly past the joint of the blade trunnion and the hub, and means formed in said annular element for draining water from said chamber.

ARTHUR G. SMITH.

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