US2926886A

US2926886A - Water turbine bucket construction

Info

Publication number: US2926886A
Application number: US501684A
Authority: US
Inventors: Hertrich Elise
Original assignee: Western States Machine Co
Current assignee: Western States Machine Co
Priority date: 1954-04-06
Filing date: 1955-04-06
Publication date: 1960-03-01
Anticipated expiration: 1977-03-01

Description

March 1, 1960 J. HERTRICH WATER TURBINE BUCKET CONSTRUCTION Original Filed April 6, 1954 3 Sheets-Sheet 1 INVENTOR AT ORNEY5 March 1, 1960 J. HERTRICH WATER TURBINE BUCKET CONSTRUCTION Original Filed April 6, 1954 3 Sheets-Sheet 2 v IIIIII/ /I III II l/ll/I/ March 1, 1960 J. HERTRICH 2,926,886

WATER TURBINE BUCKET CONSTRUCTION Original Filed April 6, 1954 3 Sheets-Sheet 3 J a 11 r "2.135 ed 5 fizei arwwazk P W ATTORNEYS Unitfiid States Patent 2,926,386 7 WATER TURBINE BUCKET CONSTRUCTION Joseph Hertrich, deceased, late of Hamilton, Ohio, by E i Hertrich, executrix, H mi ton, Oh ss ns: to The Western States Machine Company, Hamilton,.Qh i.0, a corporation of Utah. l

Original application April. 6, 1954, Serial No. 421,383. ?0li'lgt4l and this application April 6, 1955, Serial No- '4 Claims. (Cl. 253-26) This application is a division of applicants copending application Serial No. 421,383, filed April 6, 1954.

This invention relates to new and useful improvements in centrifugal machinesand particularly to suspension and driving means for gyratory centrifugals of the type commonly used for the manufacture of sugar.

The invention is particularly adapted for the improve ment of turbine-driven centrifugal machines, but various features of its construction and operation may be used to advantage for other types of suspended gyratory cen-- trifugal machines.

An important object of this invention is to provide an improved construction ofthe buckets of a hydraulic tunbine wheel of the PeltonWheel type, by which the energy of an impinging water jet will be absorbed with high efliciency in the operation of the wheel.

Another object is to provide a bucket construction which utilizes a maximum part of. the working surface of the bucket for absorbing energy from the jet while pro? viding for the positive free discharge of the spent water from each bucket. t

An impulse bucket constructed according to this invention comprises a bowl portion longer in the radial direc, tion than it. is wide, the front open side of the bowl portion presenting at its lower part a free peripheral edge lying in a radial plane from. the axis of the wheel. The

upper part of the bowl portion has an extension formed as an overhanging lipportion that slopes upwardly and forwardly so as to terminate substantially forward of the free peripheral edge- The lip portion and the merging inner surface of the bowl portion form at the outer upper part of the bucket a jet impingement surface to receive a water jet and deflect it into and thence from the base of the bowl portion for discharge over the lower free peripheral edge. t

Other objects, features and advantages of this invention will be apparent from the following detailed description of an illustrative embodiment and from the accompanying drawings thereof.

In the drawings:

Fig. l is a vertical section through an illustrative embodiment of this invention with the basket broken away and showing the turbine Wheel partially in side elevation and partially in section;

Fig. la is a horizontal cross-section taken along line 1a- -1a of Fig. 1;

Fig. 2 is a diagrammatic plan view of the water wheel and turbine nozzles, showing the relative positions of the nozzles to the wheel; r

Fig. 3 is a longitudinal cross-section'through; a water supply control valve used in the embodiment of Fig.1;

Fig. 4 is a fragmentary perspective view of a preferred form of water wheel, showing positions of the buckets assembled on the hub of the wheel;

Fig. 5 is an elevation of a single bucket looking into the bowl of the bucket;

Fig. 6 is a plan view of the bucket of Fig. 5

Fig. 7 is an end elevation "of the bucket looking at the radially outer endthereof;

Fig. 8 is a transverse crass-sectional view of the bucket taken along line 8-8 of Pig. 5;

Fig. 9 is a longitudinal horizontal sectional view of the u k t taken along l n 9 9 of Fig,-

Figs. 10 and ll are fragmentary cross sectional views of the bucket. taken at oblique angles along lines 10TH) and 11* 11, respectively, of Fig, 5 to: show the contours of lower portions of the bucket;

Fig. 12 is an elevation similar to Fig. 5, provided with contour lines to. illustrate the shape of the bucket more le r y; nd

Figf13 is a horizontal longitudinal section taken on the longitudinal median line of the bowl portion, looking upwardly toward the top of the bucket and showing by contour lines the shape of the upper part. of the bucket.

Referring first to Fig. l, a usual perforate centrifugal basket 10 is disposed within a surrounding; curb or casing 12. and is rotatably carried by a suspended spindle 11 for rotation therewith. The spindle is suspended by a suspension head, indicated generally at 13, from. a stationary hanger 14 which carries the weight of the basket and spindle The spindle 11 is formed in two separate sections 11a and 11b which are bolted together by bolts 11c that extend through bores in flanges 15 and 16 formed externally on sections 11a and 11b, respectively. a The lower section carries the basket, and the upper section is conneeted through a flexible coupling 17 with the lower end of a vertically disposed drive shaft 18, to which is secured the impulse wheel 19 of a water turbine 20. This wheel is enclosed within a water housing 21, the base of which rests on conventional supporting framework The stationary hanger 14 is formed with an integral external flange 22 by which it is bolted directly to the base of the water housing 21, as at 23.

A centrifugal brake drum 24 is detachably secured directly to the'spindle for rotation therewith and surrounds the suspension head assembly, extending axially in concentric spaced relation thereto. Drum 24 is bolted to the spindle by bolts 25 which extend through aligned bores in a flange 26 formed internally on the drum and overlapping llange 15 of spindle section 11a. The drum is arranged to be engaged by friction brake bands 27 supported from hanger rods 27:: in known manner.

A non-rotary hollow sleeve 28 surrounds the upper section 11a of spindle 11 and has an upward extension 41 that surrounds and extends to a location above the flexl plin n pa ed re a ion thereto he adia and thrust loads on the spindle 11 are transmitted d i reetly from the spindle to the sleeve 23 by vertically spaced sets of bearings 29 and 30, which are disposed between the spindle and the sleeve.

The upper bearings 29 are preferably a double set of radial and thrust ball-bearings having their inner races seated on a cylindrical portion of spindle section 11a, over shoulder 33 thereof, and their outer races resting against cylindrieal portion 31 of sleeve 28 on an upwardly facing shoulder 32 of. the leeve, and a. nut 34 threaded; on the spindle seetion bears downwardly against the inner races so as to hold the. bearings firmly in working position. A ring or cap 35 overlies the thrust bearings and is provided with passages 36 to direct lubricating fluid to the bearings from an oil chamber formed by the sleeve U extension 41. The ring 35 is confined axially between the nut 34 and the upper outer race of the bearings.

The lower bearings 30 comprise a set of self-aligning roller bearings disposed at the lower end of the gyratory sleeve 28 between opposing cylindrical portions of the sleeve and spindle 11a. The inner race abuts an annular collar 37 held between it and an enlarged spindle portion 38 below the collar.

An enlarged portion of the gyratory sleeve just below the extension surrounding flexible coupling 17 is formed with aconvexly spherical surface or ball element 39 that fits into a complementary concavely spherical, upwardly facing surface 40 of a stationary annular ring or socket element 40a. Socket element 40a is supported by the stationary hanger 14. It will be understood that the ball and socket arrangement 39-40 supports the assembly of the sleeve 28, while permitting this assembly to gyrate about the center point C of the ball and socket elements in response to unbalanced basket loads or changes of basket load distribution which occur in the operation of the machine. r

A Apositive drive connection is provided between the non-gyratory turbine drive shaft 18 and the gyratory basket spindle extension 11a by means of the flexible coupling 17 which permits the necessary oscillatory movements of the spindle assembly about the center of gyration at C, and this same coupling is here made to serve also as a radial antifriction bearing for the lower end of the drive shaft so as to eliminate the need for a ball or roller hearing at that location. Coupling 17 is disposed at the level of the center of gyration. It comprises a collar 44 fixed to the upper end of spindle section 11a and having a circular series of radial teeth 45 which are evenly spaced apart and are fitted between the spaced axially extending teeth 43a of a driving ring 43b fixed to the lower end of the turbine shaft 18. The teeth 45 of the gyratory collar 44 are crown teeth whichhave convex lateral surfaces engaging the adjacent flat surfaces of the teeth 43a on ring'43 and convex outer surfaces to engage the inner face of a sleeve 46 which is fixed to ring 43 in surrounding relation to the series of interfitting teeth 45 and 43a. The sleeve 46 serves to restrict or prevent lateral displacement of the axis of the turbine shaft relative to the axis of spindle section 11a at the center of gyration while still permitting the needed gyratory movement of the spindle assembly in the course of the centrifugal operations. By this construction, the flexible coupling serves not only to transmit torque from the turbine to the spindle but also acts as an antifriction radial bearing to sustain the lateral or radial loads acting on the lower end of the turbine shaft. Swinging movement of the basket and spindle assembly away from the normal axis of rotation is resisted by a-resilient buffer ring 42, preferably made of rubber, which is disposed at a level above the center of gyration C and is confined between an upwardly and outwardly facing seat formed by flanges 47 and48 at the top of sleeve extension 41 and an oppositely facing seat formed by an inner cylindrical surface of hanger 14 and an overhanging annular plate 49 which is movably fastened to the hanger by bolts 49a. The buffer ring 42 affords the desired yielding resistance to the gyratory movements of the basket and spindle assembly, and the degree of this resistance can be adjusted by adjusting the plate fastening bolts 49a, or by substituting a different buffer ring below plate 49, without dismounting the head of the machine. A cover or shield 78 on shaft 18 overlies a central opening 49b in plate 49, through which the coupling ring 43 may be lifted freely whenever it is desired to remove the housing 21 and the driving motor from the machine.

Further in accordance with this invention, the suspension head is provided with means for maintaining a continuous forced circulation of oil through its bearings and over other rubbing parts for simultaneously lubricating and cooling the same, and the same head is provided 4 o with means for cooling the surrounding friction brake drum 24 with a regularly replenished body of cooling water. As shown in Fig. 1, an oil inlet port 60 is formed in the side wall of hanger 14 to deliver lubricating oil fed through a conduit 61 into an annular chamber 51 formed inside the hanger between its side and the inwardly spaced upward extension 41 of sleeve 28. A concentric chamber 50 is formed at the inner side of extension 41 in surrounding relation to the flexible coupling 17. A radially extending passage 53 in extension 41 connects chamber 50 with chamber 51 so that oil fed into the latter through port 60 will overflow into chamber 50 and can be maintained at a level inundating the working surfaces of the coupling 17. I

It will be seen that the space between the spindle section 11a and the gyratory'sleeve 28 not only provides clearance to accommodate the upper and lower bearing sets 29 and 30 but also contains between these bearings an annular partition 58 which defines inner and outer passages 54 and 55, respectively, for the circulation of lubricating oil. Axially spaced flanges 56 and 57 on the inside of the gyratory sleeve 28 support and are sealed to the upper and lower ends of the partition. Thus the partition 58, sleeve 28 and spindle 11a form an inner annular passage 54 through which oil passes from the upper bearings to the lower bearings, and between the partition and sleeve 28 there is a separate annular passage 55 through which used oil may be returned to the oil supply system (not shown) in a manner yet to be described.

It will be evident that oil present in chamber 50 of the sleeve extension will flow by gravity through passages 36 of the upper bearing cap 35, will then bath all the parts of the upper bearings 29, and then will flow through the inner annular passage 54 to inundate moving parts of the lower bearings 30.

As the oil leaves the lower bearings it passes into an oil reservoir which is formed around the lower portion of sleeve 28 by means of an annular wall 59 secured to an upper surface of the flange 15 of spindle section 11a. Wall 59 is spaced inwardly from the friction drum 24 and spaced outwardly from sleeve 28, and it extends upwardly from flange 15 in that spaced relationship to a suitable location where a top wall 59a extends inwardly from wall 59 to 'form a running seal with the outer periphery of sleeve 28. This seal is formed by an inward flange 59b ,of wall 59a extending into the confines of an outwardly facing annular'groove 59c insleeve 28. An annularshieldor. cap 59d is fitted on sleeve 28 above wall 59a and extends over that wall and around it and the uppermost part of wall 59 so as to prevent cooling water inside the brake drum 24 from entering into the oil reservoir formed by wall 59.

,The oil flowing past the lower bearings at 30 thus accumulates in the oil reservoir surrounding these bearings, and as the machine is operated excess oil is regularly removed from the oil reservoir by the action of a stationary scoop 62 which is fitted into a radial opening in sleeve 28 and has an oil passageway 62a for conducting oil from the reservoir formed by wall 59 into the outer oil passage 55 formed between sleeve 28 and partition 58. As shown more fully in Fig. 1a, the scoop 62 has a mouth disposed in the path of movement of oil which rises on and rotates with the inner surface of wall 59 as the machine rotates at high speed. Since the mouth opens in a direction opposite to the direction of rotation, oil on the rotating wall 59 is scooped therefrom and flows under pressure through port 62a into annular passage 55. When passage 55 is filled with oil, the excess oil may be discharged through communicating ducts 64, 63 and 65, which extend through sleeve 28, ring 40a and hanger 22 into bore 66 or a fitting 71 connected by pipe 72 with a suitable oil cooling and supply system not shown A suction pump preferably is connected with pipe 72to assure the continued removal of used oil accumulated in. passage 55.

The excess oil in the head may be discharged by gravity, if desired, in which event fitting 71 may be removed and the hanger opening closed by a pipe plug screwed in the place of this fitting; Duct then opens into an upright duct 67 in hanger 14, which opens into an overflow pipe located at the desired maximum level of oil in the chambers 50 and51. In this arrangement, the feed pipe 61 has a shut-off valve, preferably solenoid-operated, which will stop the inflow through pipe 61 Whenever the machine stops, i.e., whenever the scoop 62 ceases to be active due to insuflicient rotation of reservoir wall 59. In this manner of use of the structure, oil pumped upward by the scoop action flows through duct 67 and is discharged by gravity through the overflow pipe 70. By reason of port 67a between chamber 50 and chamber 51, the duct 67 and overflow lubricating oilis circulated in a positive manner by ad j mitting oil into a stationary part of the head (the hanger),

passing the oil by gravity to upper and lower bearings I supporting the rotating parts of the assembly, and then forcibly returning the oil by self-contained means in the head to the stationary hanger for return to the oil cooling and supply system and subsequent recirculation through the head.

A regulated circulation of brake cooling water also is maintained during operation of the machine, the supply of this water being introduced into the brake drum 24- through inlet pipe 76 and excess water being removed from the inner surface of the drum in the running phase of each centrifugal cycle by the action of a scoop-like end of discharge pipe 77. During the running phase, the water walled up against the drum is. prevented from overflowing by top flange 24a on the drum and by the scooping action of pipe 77 When the machine is stopped, the water supply through pipe 76 is stopped by the operation of a suitable shut-off valve (not shown). The shield and sealing devices at 59b,.c and d not only prevent water inside the drum from reaching the oil inside wall 59 but also prevent this oil from spilling into the space for the cooling water.

With the described head and drive arrangement, the brake is conveniently disposed on the spindle between the driving means and the basket .of the machine and near. the center of gyration ofthe spindle and basket assembly, and all parts of the suspension head as well as the flexible coupling, the brake elements, and the feed and discharge lines for lubricating oil and brake intercepting a water jet will first cut evenly into the jet cooling water are organized together in a compact arrangement which is relatively easy to assemble and disassemble and which makes optimum use of the limited. head room normally available at the machines.

In association with the structure described above, a driving system is provided for the gyratory basket and spindle assembly having new features of construction and control which give important operating advantages. With reference to the driving unit. 20 of Fig. 1, the impulse or water wheel 19 within housing 21 has a hub to the periphery of which is fixed a set of. spaced impulse buckets 200. A pair of

nozzles

103 and 104 are spaced apart and arranged in the housing so as to direct separate jets of water against the buckets 200 at diametrically opposed parts of their orbit. At its lower end the housing 21 is provided with an outlet 106 through which water is discharged from the housing. An inner casing 107 surrounds the turbine shaft 18 below wheel 19 and slopes downwardly and outwardly to the base of the housing so as to close off the interior of thewwater housing from the upper end of the flexible coupling and .head assembly.

ing that direction.

The impulse wheelbuckets 260 have. the function of extracting energy from the water jets discharged from nozzles 103 and .104 so as to drive the wheel and the shaft and spindle connected with it. As shown more particularly in Figs. 4 to 13, the wheel 19 comprises a large number of these buckets arranged symmetrically about its axis in a uniformly spaced relation, and each of the buckets has a distinctive bowl construction which is formed to intercept the free water jets and to discharge the'water from the jets in a manner giving a very high power efficiency along with freedom from energy losses commonly caused by the discharge. of water from known impulse wheel buckets into the path of rotation of the wheel.

Each of the buckets is attached to the hub 100 by means of an inwardly extended mounting lug 205 which is integral with an upper inner part of the bucket. The lug 205 has a flat and wedge-shaped horizontal outline which adapts it to fit on the hub in close relation to the lugs of adjacent buckets, and each lug is fastened securely to the hub by screws 206.

Each bucket 200 comprises an approximately semiellipsoidal bowl portion 201 that is longer in the radial direction than it is wide and is disposed in an upright radial position with its closed side or base facing the direction of wheel rotation and its open side or front trail- At the lower part of its front side each bucket has a front peripheral edge 202 that lies in a radial plane from the axis of the wheel 100. The upper part of the bowl portion extends into an upwardly and forwardly sloped lip portion 203 which is spaced above and forward from the plane of said front pe ripheral. edge 202 and which terminates at an extreme forward point 203a near the transverse vertical median line of the bowl formation. The upper and outer quadrant of the bucket forms a. jet impingement surface 204 which is constituted in part by an outer part of the lip portion 203 and in part by the merging inner surfaceof the upper part of the bowl portion. This. jet impingement surface. receives the Wheel energizing water jet and deflects it into and thence from the base of the bowl portion for discharge over the front peripheral edge 202.

The jet impingement surface 204 terminates at'the outer limit of the bucket in a sharp edge 209 that slopes upwardly and forwardly to a corner 210 at the top of the bucket, which'corner is located near the plane of the lower edge 202. The edge 209 is so formed that it lies in a vertical plane substantially tangent to the orbit of the water Wheel. Accordingly, as may be seen from Figs. 2, 4 and 5, when the wheel is rotating the vertical edge 209 of the jet impingement surface of each bucket on a vertical line, allowing the unintercepted part of the jet to continue impinging on a bucket ahead, and as the wheel brings the intercepting bucket more. nearly normal to the jet, the place of jet impingement moves inwardly along sloped surface 204, with the center of the jet approximately on the broken line A of Fig. 5, until a final impingement position indicated by broken circle B of Fig. 5 is reached. The jet then begins to be intercepted by a following bucket.

As may be seen in Figs. 8, l0 and 11, the lower edge portion or lip of the bucket leading to the front peripheral edge 202 is flared slightly so as to direct the liquid discharged from one bucket in a path free and clear of the next succeeding bucket. As shown in Figs. 5 and 12, the front peripheral edge 2.02 of each bucket extends in an approximately elliptical form to end portions which lie above the horizontal median line of the bowl portion tinned motive power.

the inner end of the bowl portion, the front peripheral edge 202 terminates in a sharp corner 213 from which a downwardly facing inner edge 214 of the bucket extends forwardly and substantially horizontally to a lower inner corner 215 of the lip portion 203. From corner 215 the face of the upper inner portion of the bucket merges with the forward side of lug 205 and slopes forwardly and outwardly, as seen at 216 in Figs. and 8, to the forward point 203a of lip portion 203. From that point a backwardly and outwardly curved edge 217 extends to the upper outer corner 210 of the bucket structure.

As already mentioned, the jet issuing from each of the

nozzles

103 and 104 is initially intercepted bythe cutting edge 209 of each bucket as the impulse wheel rotates. The shape of the bucket formation and the slope of the jet impingement surface 204 are such that water first impinging on that surface is diverted inwardly and downwardly through the ellipsoidal bowl portion to be discharged over the free peripheral edge at 202. The bucket then is disposed at a considerably obtuse angle with respect to the jet. As this angle diminishes the jet impingement surface takes the full flow and force of the jet and the water is diverted more abruptly downwardly into the bowl portion, which absorbs fully the energy available from the jet, but the discharge of the spent water still takes place downwardly over the free edge 20?. in a path clear of other buckets on the water wheel.

In this way all the water of the jet is discharged on the lower side of the wheel 100, thereby eliminating the energy losses that result from the usual wash of considerable quantities of discharged water back over the wheel and the buckets. It will also be evident that the present construction utilizes a maximum part of the working surface of the bucket for absorbing energy from the jet while providing for the positive free discharge of the spent water from each bucket.

Control of the power developed by the water turbine for bringing the centrifugal machine to the desired full operating speed is effected by water flow control valves 117 and 117a which respectively regulate the water flow through

nozzles

103 and 104. To provide the high power necessary for acceleration of the machine, both nozzles are opened to direct two separate jets against the wheel. When the full speed is reached either of the nozzles may be closed to continue the full speed operation under the reduced power of the jet from the other nozzle, or both of the nozzles may be closed so as to allow the machine to coast at high speed without can The control valves are pressure responsive quick acting valves which are particularly suitable for remote control by suitable automatic control means.

The

nozzles

103 and 104 are mounted in the ends of respective housings 116 and 116a which form water passages 1-15 and 115a extending from the respective control valves 117 and 117a. Each nozzle housing is detachably supported as a removable segment of the water housing 21 so that it can easily be removed and replaced in order to substitute a nozzleof different size, or for any other reason.

The control valves 117 and 117a are identical in construction and operation, so the details of only one of these are shown in Figs. 1 and 3 of the drawings. As seen in Fig. 3, valve 117 includes an elongated, hollow, valve body 118 having an inlet 119 at one end, an axially aligned outlet 120 at the other end and a water chamber 118a between the ends. Outlet 120 is defined by a replaceable, wear-resistant ring 121 that forms an annular seat 121a for the conical tip 122b of an axially reciproeable valve needle 122. A substantially cylindrical needle housing 123 is disposed within and on the axis of the valve body 118 in spaced relation to the surrounding Wall of the water chamber, housing 123 being supported in' that position by ribs 124 extending from the chamber wall. The needle housing forms an elongated cylindrical chamber 125 which is open at its end nearer to outlet and which slidably receives needle 122 through the open end. A lining 126 forms the inner wall of chainher 125, and a rear end wall of this chamber is formed by a plate 128 which constitutes a spring seat having an aperture 128a to connect chamber with a cavity 127 in the rear end of housing 123a. The cylindrical stem or plunger 122a of the needle is sealed against the inner cylindrical surface of lining 126 and is provided with a series of external grooves 132 which assist the sliding and sealing actions of the needle.

The needle 122 is formed with an axial cavity 130 that opens from its rear end into chamber 125 and receives a compression spring 131 bearing against the plate 128. The spring serves to move the needle to its closed position against the valve seat under circumstances hereinafter described.

The pressure of water in chamber 118a of the valve body 118-can be transmitted into chamber 125, for ap plying pressure to the back of needle 122, through a pilot valve indicated generally at 129, a duct 135 leading into the pilot valve from chamber 118a, and a duct 136 leading into cavity 127 from the pilot valves The pilot valve 129 includes a valve body 140 having therein a chamber which communicates with duct 135 through port 146 and a filter plug 161 and communicates with duct 136 through a port 147 containing a restricted passageway or bleeder 155 for limiting the rate of water flow into and from the needle housing. The wall of chamber 145 opposite to port 146 has an outlet opening 151 which normally is closed'by a movable valve needle 144 held against the mouth of this opening by a spring 138. A forward surface 14411 of the samevalve needle is arranged to open and close the passageway through port 146 by movement of the needle relative to seal element 143 in port 146, the arrangement being such that port 146 is open when port 151 is closed by needle 144 and port 151 is open when port 146 is closed thereby. When port 151 is open, water can flow freely through it into a chamber 149 of the pilot valve body and thence through port 150 at the bottom of 7 admitted into this chamber, and when the pressure against diaphragm 137 of air in chamber 139 exceeds the pressure of spring 138, the valve needle 144 is moved from its normal position in which port 151 is closed to a position in which port 146 is closed.

Accordingly, the admission of compresed air to the pilot valve through conduit 160 serves to close the passageways connecting the water chamber 118a with the main needle chamber 125 and to release through bleeder 155 and port 151 any water pressure existing in chamber 125, while the venting of air pressure from the pilot valve serves to interconnect chamber 118a and chamber 125 so that the pressure of water in the former will be transmitted into the latter and thus will be applied to the rear end of the plunger 122a of needle 122. It results that in the normal position of the pilot valve, the full water pressure being applied to the rear end of the valve needle 122, this pressure together with the force of the spring 131 will move needle 122 to its closed position where the needle will be held as long as the pilot valve stays in normal position thus preventing the passage of water to the

nozzle

103 or 104 of the impulse wheel.

It will be noted further, however, that the plunger portion 122a of needle 122 terminates at a forwardly an inch,away from seat 121a.

facing shoulder 134 on, a, forward part of this needle within water chamber 118a. This shoulder presents a sufficient area that the backward pressure exerted against ityby the water present in chamber 118a, substantially exceeds the forward seating force exerted on needle 122 by the weight of the needle and/or by the compression spring 131 when the needle is in its seated position. Accordingly, when the pilot valve 129 is moved from its normal closed position to its other or active position, the water pressure normally applied against the back end of needle 122: is released from chamber 125, and the backward pressure still exerted on shoulder. 134 then moves needle 122 away from its seated position. To facilitate this unseating movement, the spring 131 may be made or arranged so that it exerts little or no force until the needle has moved a substantial distance, say A; of As the needle moves to open port 120, the conical end surface 122b also becomes subject to the pressure of the water supply; so this pressure continues to move the needle backward against spring 131 until the valve is fully open. water in chamber 118a then flows under its full pressure through port 120 and passage 115 or 115a to form a wheel-driving jet as it issues from the

water nozzle

103 or 104.

If any failure occurs in the supply of air pressure for the pilot valve, the corresponding water jet driving the machine is automatically cut off by action of the control valve, due to the release of air pressure from chamber 139 and the resulting closing movement of needle 122.

In the use of the disclosed machine, the inlet 119 of each control valve is connected with a source of water held constantly under a pressure suitable for driving the water turbine, and the compressed air line 160 of each valve is connected through a suitable air valve, for example, a hand operated or solenoid-operated three-way air valve, with a source of air held constantly under a pressure sutficient to overbalanc'e the pilot valve spring 138. When a solenoid-operated air valve is used, it may be actuated by electrical control means of a type widely used for controlling the operations of sugar centrifugals.

If the machine is to be used with a mechanical discharger for discharging solids from the centrifugal basket, the drive shaft 18 preferably is extended above the water wheel, as indicated at 250 in Fig. 1, so as to pass through a top bearing shown at 252 and be connected with the driven clutch element of a low speed discharge drive mechanism of the type disclosed and claimed in United States Letters Patent No. 2,667,974 of Joseph Hertrich.

The operations of the present machine are carried out in any of the ways used for sugar centrifugals or other heavy cyclical centrifugal machines. When the basket is ready to be accelerated to its full running speed, compressed air is admitted to line 160 of each of the control valves 117 and 117a, whereupon the valves open and water jets from the

nozzles

103 and 104 impinge against the buckets 200 of the impulse wheel. The machine then accelerates under the energy absorbed from the jets, and when the full running speed is reached at least one of the jets is cut off by releasing the compressed air from the corresponding pilot valve. This can be done manually or by actuating an air valve on line 160 by an automatic time-controlled or speed-controlled mechanismtnot shown). Meanwhile, the spent water from the jets leaves the buckets 200 entirely beneath the water wheel 100 and passes through chamber 108 of the water housing to the water outlet 106.

When the machine has run for the desired period at high speed, both of the water control valves are closed and the brake 27 is applied in known manner to bring the machine to rest. During all the running period, oil is fed through pipe 61 into the lubrication system of the head, excess oil is returned to the oil supply tank (not shown) through pipe 70 or pipe 72 cooling water is 20 The fed into the brake drum through pipe "76, and excess water is, discharged from the drum through, scoop pipe 77.

It will be understood that each of the several new features and combinations of this invention, either alone or in combination with other new features here disclosed,

may be embodied. in various forms of apparatus without restriction to details of the illustrated embodiment.

What is claimed is:

1. A hydraulic impulse turbine wheel comprising a horizontal circular series of impulse buckets rotatable about a vertical axis by a substantially horizontal free liquid jet, each of said buckets comprising a cup-shaped body mounted on a radius from said axis with its concave side disposed vertically to face and intersect said jet in a part of its orbit, the concave side of said body comprising a central base portion elongated in the direction of said radius, a lower portion extending forwardly from the lower side andthe ends of said base portion with an approximately ellipsoidal curvature to, and terminating in a free front edge bordering the lower part of said body and lying in a vertical plane approximately aligned with said axis, and a forwardly and upwardly sloped upper surface portion extending from the upper side of said base portion to a location near the top of said body, the last-recited portion forming a sloped jet impingement surface a major portion of which, near the vertical median line of said body, is disposed for-- wardly of said plane to receive said jet and deflect it downwardly in said body for the discharge of spent liquid over said front edge.

2. A hydraulic impulse turbine wheel comprising a horizontal circular series of impulse buckets rotatable about a vertical axis by a substantially horizontal free liquid jet, each of said buckets comprising a cup-shaped body mounted on a radius from said axis with its concave side disposed vertically to face and intersect said jetin a part of its orbit, the concave side of said body comprising a central base portion elongated in the direction of said radius, a lower portion extending forwardly from the lower side and the ends of said base portion with an approximately ellipsoidal curvature to, and terminating in, a free front edge bordering the lower part of said body and lying in a vertical plane approximately aligned with said axis, and a forwardly and upwardly sloped upper surface portion extending from the upper side of said base portion to a. location near the top of said body, said upper portion extending forwardly in a pointed formation near the vertical median line of said body to form a sloped jet impingement surface which at that line is predominantly disposed for wardly of said plane to receive said jet and deflect it downwardly in said body'for the discharge of spent liquid over said front edge.

- 3. A hydraulic impulse turbine wheel comprising a horizontal circular series of impulse buckets rotatable about a vertical axis by a substantially horizontal free liquid jet, each of said buckets comprising a cup-shaped body mounted on a radius from said axis with its concave side disposed vertically to face and intersect said jet in a part of its orbit, the concave side of said body comprising a central base portion elongated in the direction of said radius, a lower portion extending forwardly from the lower side and the ends of said base portion with an approximately ellipsoidal curvature to, and terminating in, a free front edge bordering the lower part of said body and lying in a vertical plane approximately aligned with said axis, and a forwardly and upwardly sloped upper surface portion extending from the upper side of said base portion to a location near the top of said body, the last-recited portion forming a sloped jet impingement surface a major portion of which, near the vertical median line of said body, is disposed forwardly of said plane to receive said jet and deflect it downwardly in said body for the discharge of spent liquid'over said front edge, said front edge having end portions extending upwardly 11 in said plane in bordering relation to the radially outward and inward limits of said body to terminal points iocated substantially above the horizontal median line of said body.

4. A hydraulic impulse turbine wheel as described in claim 3, each of said buckets comprising also a backwardly cut out portion in the wall of said body forming a jet entrance gap above the outward terminal point of said front edge, the bordering edge of said gap lying in a vertical plane substantially tangent to the outermost circle of the orbit of said body and its upper portion being sloped forwardly and upwardly at the outward limit of said upper surface portion.

References Cited in the file of this patent UNITED STATES PATENTS Gfeller Nov. 8, Pfau Dec. 13, Herr Oct. 9, Schmidt Sept. 6, Moody Sept. 23,

FOREIGN PATENTS Great Britain Feb. 27, France July 2,