US1698299A

US1698299A - Governing mechanism for prime movers

Info

Publication number: US1698299A
Application number: US692615A
Authority: US
Inventors: Edgar D Dickinson
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1924-02-13
Filing date: 1924-02-13
Publication date: 1929-01-08
Anticipated expiration: 1946-01-08

Description

r w ffm Jan. 8, 1929.

In\/en tor-: Edgar' D. Dickinson, by l;

ng. z.

His Attorney.

Patented Jan. 8, 1929.

UNITED STATES VPATENT OFFICE.

:EDGAR D. DICKINSON, OF BEVERLY, MASSACHUSETTS, ASSIGN OR TO GENERAL ELEC- TRIO COMPANY, A CORPORATION OF NEW YORK.

GOVERNING MECHANISM FOR PRIME MOVERS.

Application filed February 13, 1924. Serial No'. 692,615.

The present invention relatesto governing mechanisms for prime movers such as elastic fluid turbines. The object of my invention is to provide an improved governing mechanism and for a consideration of what I believe to be novel and my invention, attention is directed to the accompanying description and the claims appended thereto.

In the drawing, Fig. 1 is a diagrammatic view of a governing mechanism embodying my invention; Fig. 2 is a sectional 'View takenon line 22, Fig. 1, the view being on an enlarged scale; Fig..3 is a sectional view taken on line 3-3, Fig. 2; Fig. 4 is an enlarged detail view of the governor and the pilot valve which it operates, and Fig. 5 is an enlarged detail'viewof the governor I connection.

Referring to the drawing, 5 indicates the admission end of an .elastic fluid turbine to which elastic fluid is admitted by suitable' valve means 6 which is opened and closed by turning movements of a cam shaft 7.

The turbine shaft is indicated at 8 and the oil tank at 9.

might be used, ordinarily it would not be,

but instead a single tank would be provided. In reality in Fig. 1, the tank structure 1s two sections of the same tank placed side by side. f` On the vend of .cani shaft 7 is a, pinion 11 which meshes with a rack l2 formed on a" tubular member 13. Member 13 is mounted on the upper end of a rod 14 being located between a shoulder 15 on rod 14 (see Fig. 2) and a nut 16 screwed onto theupper end of a rod 14. The lower end of od 14 is connected to a piston 17 located in a cylinder 18 and biased towards the bottom of the cylinder by a spring 19 located between the top surface of the pistonand a spring plug 20 fastened to the upper end of cylinder 18.

The arrangement is such that when piston 17 moves upward it opens valve means 6 and when it moves downwardv 1t effects closing of such valve means. The detail structure of the valve means is not illustrated as it forms no part of the present invention. Any suitable valve means arrangement adapted to be opened and closed by movements of rod 14 may be used. The particular valve means indicated in the drawing is that which forms the subject matter of the application of Dickinson and Standerwick Sr. No. 692,601 filed of even date herewith.

On turbine 'shaft 8 is a worm 21 which meshes with a Worm wheel 22 mounted on a vertical shaft 23. Shaft 23 is mounted in suitable bearings one of which is Aindicated at 24 and at its lower end is connected to drive an oil pump 25 located in tank 9. Pump 25 takes oil from tank 9 through a suitable intake strainer 26 and delivers oil through a conduit 27 to a pipe 28. Connected to pipe 28 isa pressure relief valve 29 which discharges back to tank 9 and 'which is set to maintain in pipe 28 a certain desiredpressure. Pipe 28 delivers 'oil through an orifice 3() in a plate 31 to a pressure pipe 32 and a by-pass pipe 33 which Htl branches therefrom. Since there is a constant pressure in pipe 28, oil will be delivered through orifice 30

tov pipes

32 and 33 always at a definite rate depending upon the pressure existing in such pipes.` Pipe 32 is connected to cylinder 18 beneath piston 17 and conveys pressure to the underside of the piston for. e'ecting operation of the valve means 6. Bypass pipe 33 is connected to an annular chamber 34 in the inner wall of a pilot valve casing 35. In casing 35 is a bushing or sleeve 36 provided with ports 37 located in alignment with chamber.` 34, Bushing y36 extends throughout thelength of casing 35 and is connected at its upper .end to a lever 38 which is fulcrumed on the upper end of an arm 39 which in turn is pivotally supported on a flange at the base of pilot valve casing 35. Inside'bushing or sleeve 36 is a pilot valve 40 which is .in the form of a tube or sleeve and is connected at its lower end directly to the weight arms of a centrifugal speed governor so as to turn therewith. To this end sleeve valve 40 is fastened to an upper spring plug 41 which is connected toa lower spring plug 42 by a spring 43. The lower spring plug is provided with a. stirrup 44 in which the ends of governor Weight arms'45 lie, the end of the arms overlapping each other. The under arm end is pivotally connected to the stirrup by a pin 46. The upper arm end is provided with a pivot bearing 47 between which and a pivot bearing 48 on spring plug 41 is located a pivot rod 49. The engaging surfaces ot the overlapping ends of arms 45 are curved so as to rock on each other and are kept in engagement with each other by pivot rod l49 which is held in its pivot bearings by spring 43. The governor weights 50 are pivoted on the arms of a yoke 51 by pin bearings 52 and are connected to each other by a governor spring 53. The arrangement is such that the center of mass o the governor weights is on the line of pull on spring 53. This permits of the use of pin bearings because of the fact that with this arrangement there is very littleside thrust on the bearings and hence but little friction.

Yoke 51 is fastened directly 'to the upper end of shaft 23. Spring 43 forms a driving connection between pilot'valve 40 and the governor so that the pilot valve turns with the governor, and in conjunction with pivot rod 49 forms a connection between the pilot valve 40 and the overnor for transmitting axial movements rom the governor to the pilot valve.

Lever 38 is connected by a link 55 to a lever 56 which at one end is fulcrumed on a fixed arm 57. The other endof lever 56 is connected to rod 14 in such manner that the connection can be adjusted vertically along the rod to vary the setting of the governor. This connection is shown more particularly in Figs, 2 and 3. It comprises a bracket structure havin a tubular portion 58, a plate 59 and a rame 60. Tubular portion 58 is mounted on rod 14 being heldbetween a shoulder 61 on the rod and the lower end ,of rack member 13. At the lower end of tubular portion 58. is an adjusting bushing 62 and at its upper end are slots 63 which receive tongues or pro'ections 64 on the llower end of rack mem er 13. These pro- 'ections 64 on the rack member 13 hold the racket structure from turning, the rack member being held from turning by reason of the' enga ement of the rack teeth with pinion 11. rame has spaced bearings 65 in which is mounted a threaded rod 66. On the upper end of rod 66 is fixed a worm lwheel 67 which meshes with a worm 68 having a'shaft 69 mounted in bearings 70. The under side of worm wheel 67 rests on top of the upper bearing 65 and is held in engagement therewith by av stud 71. This forms a sort of step bearing for rod 66. Mounted on rod 66 is a traveling nut 72 provided with wings 73 which engage side walls of the frame to prevent the nut from turning thus limiting its movements to vertical movements along the rod. Projecting from nut 72 are two spaced parallel ears 74 Lacasse 69 by a suitable coupling 79. Motor 78 is the motor for adjusting the setting of the governor (usually termed a synchronizing motor), and it will be clear that when operated in one direction it will turn rod 66 in a direction vto cause nut 72 to run downward on rod 66 thus lowering the connection between lever 56 and rod 14 while when operated in the opposite direction it willturn rod 66 in a direction to causenut 72'to runupwar'd on rod 66 thus raising such connection. is an oil cup for worm gearing 67, 68.v

At 81 -is a hand oil pump comprising a cylinder 82, a piston 83 and a hand wheel side of pump'81 is connected by a pipe 85. to' the oil supply in tank 9 and the discharge side is connected by a pipe 86 to pressure pipe 32. The purpose of this pump is to bulld up a pressure in pipe 32 to raise piston 17 'and open valve means 6 when vstartfing up. At 87 is a non-return or back pressure valve which closes when pump 81 is operated to prevent oil escaping back through pipe 28. When valve means 6 is closed and the speed governor is standing still pilot valve 40 is of course in a position to close ports 37.

When the turbine is running, oil pump 25 maintains a definite pressure 1n pipe 28 and the oil flowing through orifice 30 maintains a definite pressure in pressure pipe 32vand bypass pipe 33 depending upon the extent to which ports 37 are uncovered by pilot valve 40, it being understood that when ports 37 are uncovered oil can escape from pipe 33 through ports 37 and the inside of pilot valve sleeve 40 to tank 9. Thepressure in pressure pipe32 acts on the underside of piston17 and holds it against the action of sprin 19 in a. position wherein valve means 6 1s opened to the extent required to maintain the desired speed If now the lspeed increases the speed governor Weights 50 will move out thus lowering pilot valve sleeve 40 and uncovering further ports 37.. This permits the ymore rapid esca e of oil from pipe 33'through ports 37 tliereby eil'ectinir a decrease in the pressure in pipe 32 and under piston 17 whereupon spring 19 forces piston 17 downward tol close somewhat valve means 6 so as to decrease the supply of elastic fiuid to the turbine. When piston 17 moves downward it carries with it the end of lever 56 becauseof its connection to rod 14 and this lowers the left4 hand end of lever 38 and hence moves bushing or sleeve 36 downward.

sa Y 84 for operating the piston. The sucto v f valve so as to close the ports somewhat and prevent overtravel or hunting of the valve mechanism. With decrease in the .supply of elastic fluid the turbine returns valve sleeve 40 takes the place of the usual follow up connection for the pilot valve and operates to produce the same result.

lVith the above construction it will be noted that the pilot valve 40 is connected directly to the governor and revolves therewith.` This keeps the pilot valve continu? ously in motion so'that there is no danger of its becomingstuck. The pilot valve 40 may be made very light in weight so that it places very little .load on the governor Vweights and but little force is .required to move it axially. As a result the governor is required to do but very little work so that it may be made small and extremely simple and sensitive. s

The pump 25, the governor, the worm gearing and the pilot valve mechanism are assembled as a unit beingr all carried by a frame 88 which is mounted on the top of the oil tank and projects through an opening therein. The walls forming conduit 27 and providing the bearing supports for bearings 24 form a part of this frame. By this arrangement the pump, the governor' and pilot' valve structure can be assembled and tested as aiunit before being connected up with the turbine. This isof particular advantage because it greatly simplifies andre duees the cost of testing the pump and gov ernor and insures that when it is assembled on the machine it will bein proper working order.

Referring now to the adjustment of the p governing melchanismfor different speeds,

this is accomplished by changing the setting of bushing or sleeve 36, relatively to the speed governor and pilot valve 40. Assume for example that the turbine is operating at a certain normal speed and that it is desired to set it for a higher speed. This is done by lowering bushing 36 relatively to pilot valve 40 so as to close somewhat ports, 37 which results in building up of the pressure in pipe 32 and a further opening of valve means 6. The turbine will then increase in speedand governor weights 50 will therei upon assume a new position drawing down pilot valve 40 untill equilibrium is established' at a new and higher speed. To set the governor for a lower speed bushing 36 is raised relatively to pilot valve 40 thereby opening further ports 37 which effects a decrease in the pressure under piston V 17 whereupon it is lowered and valve means 6 closed somewhat. The speed of the turbine then decreases andthe speed governor assumes a new setting, at the same time .raising pilot valve 40 until equilibrium is again restored. In the present instance the adjustment of bushing 36 to set the governor mechanism is accomplished through the same lever .system as that which is utilized to provide a follow up meehanismvfor stabilizing the actionl of the governor, this beingy accomplished by connecting the end of lever 56 to rod 14 by means of the adjustable connection already described. As is well understood the motor 478 is provided with the usual circuit connections whereby it may beoperated in either direction for raising or`lowering the end of l'ever 56 and thereby raising or lowering bushing 36 to change the setting of the governor. It will be clear that in vadjusting the governing mechanism for different speeds the essential thing is that the position of bushing 3G be changed. This may be accomplished of course by adjusting the lever system at a point other than at itspoint of connection with rod 14.-.

In accordance with the provisionsof the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I 'now consider to represent the best embodiment thereof,

Vbut I desire to have it understood that the 1. In combination, a prime mover, a valve mechanismeontrolling the flow of elastic fluid to the prime mover, a speed overnor, a

fluid-actuated motor for the Va ve mecha-A nism, a pilot valve for the motor comprising a cylinder of relatively light weight having-a direct connection with the speed governor so that 'it rotates therewith, said Lconnection being circumferentially yieldable, 'and meansv in said connection for moving the pilot valve axially r`in response to movements of the speed governor.

2. In a governing mechanism for prime movers, the combination with a pilot valve' mechanism having a valve element, of a speed governor, and means connecting the valve element to the speed governor so that it'rotates therewith andmay be moved axially thereby, said means comprising a circumferentially-yieldable connection for effecting the rotating movement, and a rigid connection for effecting the axial movement.

3. In a. governing mechanism for prime movers, the combination of a frame, a shaft journaled in the frame, a speed governor mounted on the shaft, a pilot valve structure mounted on the'frame, in axial alignment with the shaft, said structure comprising a movable element, and means connecting the v movable element directly to the speed governor so that it rotates therewith and may be moved axially thereby, said means comprising a circumferentially yielding connection for effecting the rotating movement, and a rigid connection for effecting the axial movement.

4. In a governing mechanism for a prime mover, a unitary structure comprising a' frame, a` shaft journaled in the frame,` a speed governor mounted on the shaft, a pump'fcarried by the frame and connected to the shaft, a pilot valve mounted on the trame and connected directly to tlie speed governor, a preure conduit and a by-pass conduit connected with the pump, said by-pass conduit being connected with the pilot vaive, a non-return valve and an orifice interposed between said conduits and the pump, a pressure cylinder connected with the pressure and the Apilot-valve, said ,pilot valve being movable axially by the speed governor to cover and uncover said perforations, and

means providing a connection between the.

traveling nut and the perforated sleeve for vmoving the'same with respect to the pilot valve when the traveling nut is moved.'

5. In a governing mechanism for a prime mover, a unitary structure comprising a frame, a shaft journaled in the frame, a speed governor mounted on .the shaft, a pump carried by the frame and connected to the shaft, a pilot valve mounted on the frame and connected directly to the speed governor, a tank on which said unitary structure is `mounted with the pump depending therein, an admission valve mechanism for the prime mover, means for operating said mechanism,

a rod providing a connection between the operating means and the admission valve mechanism, a plate carried by said rod, a

motor mounted on said plate, bearings cai' ried by said plate, a threaded rod mounted in said bearings, a traveling nut on said rod, means yproviding a driving connection be tween the motornnd the rod, a sleeve surrounding the pilot valve, and means providing a connection between the traveling' nut and the sleeve for movingv the same with respect to the pilot valve when the traveling nut is moved. l

In witness whereof, I have hereunto set my hand this eleventh day of February, 1924.

- EDGAR D. nicKiNsoN.