Патент USA US2407455код для вставки
Sept. 10,1946. ‘2,407,454 ‘ P. w; SEEWER’ AUTOMATIC SPEED LIMITING DEVICE FOR HYDRAULIC TURBINE ROTORS Filed Dec.‘ 28; ‘1942 3 sheetsfsheet l 27 ..r. . 3\HQ m 4 . a?!“v. 1.. \ m .6 . ‘I 2 |..<\\\.\\. ,7!Bl .?iv1.~ 0o U SePt-10,1945-‘ ' - ‘,VP. W.’SEEWER ' ‘ 2,407,454 AUTOMATIC SPEED'LIMI'I‘ING DEVICE FOR HYDRAULIC TURBINEROTORS \Filed 06¢ 28, 1942 a Sheets-Sheet 2~ ~ Sept. AUTOMATIC 10, SPEED LIMITINGv ' P. DEVICESEEWER FOR HYDRAULIC TURBINE ' _ ROTORSI Fil'ed Dec. 28, '1942 _ ' :s Sheets-Sheet ‘s Patented Sept. 1Q, 1946 ' ' 2,407,454 UNITED STATES PATENT; OFFICE AUTOMATIC SPEED LIMITING DEVICE FOR HYDRAULIC TURBINE ROTORS ' Paul Werner Seewer, Rugby, England, assignor to The English Electric, Company Limited, ‘Lon don, England, a British company Application December 28, 1942, Serial No. 470,396 In Great Britain January 12, 1942 screams. (01. 253-7443) .1 This invention relates to hydraulic turbines and has for its object to prevent automatically ex cessive runaway speeds. Although of general application it is of particular value when applied to turbines having swivelling propeller type blades a 2 vertical shaft 4 terminating in the hollow hub 5 carrying the swivelling blades 6. Secured to the. hub immediately above the blades 6 is the ring 1 incorporating the automatic speed-limiting device according to the invention. Within this ring are mounted a number of brak ing vanes 8 each of which is hinged as shown in Figs. 1 and 3 about a hinge pin 9 ,with its axis in difficult. , a plane transverse to the rotor axis. Normally The invention consists in speed-limiting means each of the vanes 8 is retained in the position mounted on the turbine rotor and adapted, if a 10 shown in full lines so as to be exactly flushwith predetermined speed be exceeded, to project into since as is Well known the problem of guarding against runaway of such turbines is particularly the curved circumferential surface of the ring 1 the stream and limit the speed of the rotor by which is a smooth continuation of the surface of exerting a braking torque thereon or by diverting the hub 5. vWhen under the action of centrifugal or otherwise disturbing the water on its way to the driving blades or by having a combination of 15 force these vanes turn about their pivot pins 9 the water vpressure——as soon as the tips of the these effects. vanes emerge-assists the vanes to fly out. In Preferably, the device according to the inven their outer position, the vanes 8 create a disturb tion consists of a speed-limiting unit in the form ‘ ing action on the incoming stream thereby‘re of a ring fastened to- the hub of the turbine rotor ducing the driving torque exerted by the water adjacent to and preferably above the turbine on the turbine driving blades while at the same blades. Hinged or slidably mounted on or within this ring are braking or de?ecting vanes or like members normally retained against the action of time these vanes 8 can exercise a powerful brak ing torque on the rotor by reason of their having to act against the incoming water stream. centrifugal force and held out of the stream. Although the device is e?ective if the vanes 8 When a certain speed is exceeded centrifugal 25 be parallel to the rotor axis, the drawings show force causes these members to project into the the axes of the hinge pins 9 inv planes which, stream. , although transverse to the rotor axis, are not One form of the invention is .illustrated by horizontal but inclined at an angle other than Figures 1-4 and Figures 6 and '7 of‘the accom panying drawings, of which Figure 1 is the left 30 90° to the rotor axis whereby the vanes 8, when they swing out, are not parallel to but are inclined hand half of a vertical cross-section through a to the rotor axis oppositely to the direction of complete hydraulic turbine of the swivelling pro the blades 6, as shown in Fig. 4, their surfaces peller bladed type incorporating the invention; thus having a more marked tendency to divert Figure 2 is an enlargement of apart of the upper the incoming water on its way to the driving end of the turbine shown in Figure 1; Figure 3 35 blades 6. It will be‘appreciated, however, that is an enlargement of, the pivoted braking vane the axes of the hinge pins could be either hori shown in Figure 1; Figure 4 is a perspective zontal or vertical and the surfaces of the vanes view-showing the swivelling blades and a ring either vertical or specially shaped to divert the of braking vanes of part of the rotor of the tur water. 40 bine shown in Figure 1, the vanes projecting in Hinged vanes 8 are counter-balanced by por the fully operative position; Figure 5 is a view tions such as 80 in Fig. 3 to reduce the effect of corresponding to Figure 3 of a slightly modi?ed centrifugal force, thereby allowing of the use of form ofv braking vane; and, Figures 6 and '7 are weaker retaining means. inclined views of a detail of Figure 2, but to a 45 The vanes are provided with means normally retaining them flush with the ring 1 until a cer larger scale than Figure 2. tain centrifugal force and hence a certain speed ' In Fig. 1 the turbine is of conventional swivel is exceeded. These retaining means may be ling propeller bladed type. . The stator includes springs; alternatively they may be breaking links the enveloping turbine casing I from which the incoming water flows through the spaces between 50 which are snapped by the action of centrifugal force, or they may be a combination of springs the pivoted shutters 2 on its way to the rotor and breaking links as shown in Figs. 1 and 2. blades. The shutters are operated in the usual As shown in Figs. 1, 2 and 3 each vane 8 is con manner by the lever and link mechanism indi nected by a ?exible cable l9-e. g. a steel wire cated at 3 under the automatic (control of the turbine speed governor. The rotor comprises the 55 rope—passing over an adjacent pulley ill on the f“ 3 2,407,454‘ rotor and vertically along a groove formed be tween the vertical shaft 4 and the usual protec tive sleeve l2 thereon (see Fig. 1) to the retain ing means at the upper end of the shaft shown in the enlarged view Fig. 2. The upper end of the cable NJ is coiled around and anchored to the drum l3 mounted on one of a number of bearings 2! carried by the rotor. Turning with the drum I3 is another drum l4 while coiled 4 device, thus releasing the link rod 16. At this speed the centrifugal force acting on the vane 8 causes a pull on the upper cable is which while insufiicient to snap the reduced portion Ilia of the breaking link 16 is more than su?ioient to overcome the upward force of the spring 19. Ac cordingly on the release of the latch device, all the vanes ?y out substantially simultaneously under the action of centrifugal force aided by the around and anchored to the latter is another 10 action of the water once the vanes have started cable l5 directly attached to a link rod [6, the to move. In the unlikely event of any latches 20 upper end l6a of which is of such reduced cross not releasing, the individual breaking links l6 section as to snap when the desired pull is applied will snap under the action of the centrifugal to the link which thus serves as a breaking link force at a slightly higher speed and so allow each for releasing the associated vane 8 under the ac-. 15 vane to ?y out. When the turbine rotor has sub tion of a predetermined centrifugal force. In the sequently been brought substantially to a stand arrangement shown the drum I4 is of smaller still, the springs H can pull up the cables l5 diameter than the drum l3 so that the combina and Ill to their normal position. and. withdraw the tion forms a reducing arrangement whereby the vanes into the ring 1. movement of the broken link rod l6-—when the 20 Operation of the speed limiting device can be associated vane flies outs-is less than the move seen since the latch 28 visible and downward ment of the cable Ill, but it will be understood movement of the link rods !5 can be observed. that these drums could, if desired, be both of the ‘To facilitate this observation, markings Ila may same diameter or that the cable 10 could be di be provided on the shaft adjacent to the ?ange oi" rectly connected to the link rod IS. the collar 58 which moves down with the link 16. The link rod l6 slides through a guide sleeve 57 Failure of any one of the retaining devices-wom carried by the rotor and carries towards its upper prising the combination or" breaking link l6 and end a collar [8. Surrounding the sleeve 51 and spring i9—~to retain or withdraw its associated the collar it‘ between the flanges thereon is the ' coiled compression spring I9 which is a compara tively light spring exerting on the cable l0 only suf?cient force to retain the associated Vane at a comparatively low speed of the rotor. The described retaining devices-one for each of the vanes 8—are arranged in a ring around the shaft and all are normally held up by the engagement of the upper end of each link rod IS with a latch‘Zil' which can be released in known manner by the ordinarily provided over speed trip device. The well-known form of op erating member for ‘this device—comprising the tappet pin 22 which, under the action of cen trifugal force, can slide (against the action of the spring 23) radially outwards in the sleeve portion 24a forming part of the annular struc ture 24 secured to and carried around by the shaft 4--can be seen in Figs. 2 and 6. The tappet 22, when it moves out, engages and moves the operating lever 21 of the Well-known comple mentary part of the trip device attached to a ?xed portion of the turbine casing, which part sets in motion valve means to cut off the supply of water to the rotor blades of the turbine, as already mentioned. The upper end of the said operating lever 21 which can be seen at 26 in Figures 2, 6 and 7 is then in a position to engage the end of each latch 29 as they are moved in suc cession past the lever 27 by the rotation of the shaft. Each latch 20 is shown as being movable clear of the underside of the head of link rod part ltd by turning about the vertical pivot pin 25 secured on and carried around with the said annular structure 24, and will be so moved by the engagement with the ‘end 26 of lever 21. Figure 6 shows the tappet 22 in its normal posi- tion when it is just passing the lever 21, while Figure '7 shows one of the latches 20 just passing the upper part 26 of the lever 21; the chain lines in Figure 7 show the position of part 26 when the tappet 22, in response to excessive overspeed, has engaged lever 21, in which position part 26 can engage and move latch 29 as the turbine vane 8 can also be seen. In the unlikely event of breakage of any one of the cables [0 or E5, the associated spring is will force the free upper end of the link rod it above its normal position and this again can be seen. The retaining means, being outside the water, are readily available for adjustment 'or replacement of the springs l9 and for replacement of the breaking links it after snapping. A modi?cation is shown in Fig. 5 which is a section through one vane and an end View of an other vane of a ring of retarding vanes 8 each slidably mounted within the ring 7 but with its vsurface shaped for diverting the incoming water, as can be seen from the said end View. The slid ing vane 8 (shown in its outer position by the - chain lines) takes the place of the pivoted vane B of Fig. 3 and is connected by the ?exible cable Ii] to retaining means exactly as already de scribed with reference to Figs. 2 and 3; it will be clear that this sliding vane will tend to move out into the stream under the action of centrifugal force just as ‘does the hinged vane previously de scribed. What I claim as my invention and desire to ‘secure by Letters Patent is‘: 1. In combination, a hydraulic turbine rotor, driving blades mounted on the rotor, a ring of ‘speed-limiting vanes mounted on the rotor and free to move outwardly ‘under the action of cen trifugal force into the water stream to limit the .5, speed of the rotor, a ?exible cord attached to each of said vanes and extending along the rotor to an exposed position above the water stream, guide pulleys for said cords and means holding the ends of said cords at the said position above . the water stream to retain said speed-limiting vanes out of the water stream until centrifugal vforce corresponding to a predetermined safe rotor overspeed is exceeded. 2. In combination, a hydraulic turbine rotor, driving blades mounted on the rotor, a ring of speed-limiting vanes mounted on the rotor and movable under the action of centrifugal force rotor rotates. ' into the Water stream to limit the speed of the On a predetermined speed being exceeded, the rotor, operative connections between said vanes latch device 20 is released by thev overspeed trip 75 and an exposed position above the water stream, 2,407,454 6 force on the vanes (transmitted through the op erative connections) at a predetermined exces 3. In combination, a hydraulic turbine rotor, driving blades mounted on the rotor, speed-lim iting vanes mounted on the rotor and movable under the action of centrifugal force into the water stream to limit the speed of the rotor and sive rotor speed, springs exerting on said oper ative connections a vane-retaining force but so proportioned as to be overcome by centrifugal stream, said retaining means having a weakened part proportioned to break when the force there force at a comparatively low rotor speed, a latch on due to a predetermined safe overspeed of the links at that position holding the ends of said operative connections, said links being propor tioned to snap under the action of centrifugal means retaining said vanes out of the Water device retaining each of said links (together with 10 turbine is exceeded. the said springs) and latch-releasing means re sponsive to an excessive rotor speed below that speed at which the links are proportioned to break. PAUL WERNER SEEWER.