US1441300A - High-speed governing apparatus - Google Patents

Description

Jan. 9, 1923.

, H. F. SCHMIDTl HIGH SPEED GVERNING APPARATUS.

2 SHEETS SHEET l.

FILED APR.1B, 1918.

Jan. 9, 1928. 1,441,300. H. F. scHlvunT.

HIGH SPEED GOVERNING APPARATUS.

FILED APR.18, |918. y 2 SHEETS-SHEET 2.

lgwENToR a Patented Jan. 9, 1923.

UITED STATES PATENT OFFICE.

HENRY F, SCHMIDT, OF WILKINSBURG, PENNSYLVANIA, ASSIGrNOR TOFWESTING- HOUSE ELECTRIC & MANUFACTURING CO., A CORPORATION OE PENNSYLVANIA. l

` HIGH-SPEED GOVERNING APPARATUS.

4Application led April 18,1918. Serial No. 229,335.

To all whom it may concern Be it known that I, HENRY F. SCHMIDT, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny 5 and State of Pennsylvania, have made a new and useful Invention in High-Speed Governing Apparatus, of which the following is a specification.

This invention relates to governing mechanisms for such apparatus as turbines and has for an objectto produce a simple and effective governor which is capable. of being operated at high speeds and which may be adjusted while in operation.

A further object is to produce a governing mechanism in which the governing or moving parts do not rotate with the actuating shaft of the governor, nor impart axial thrust to the 'rotating member. Y

A further object is to produce afgoverning apparatus in which there are no revolving weights or knife edge supports between rotating and reciprocating parts.

A further object is to produce an oil pressure *governor in which means are employed for governing the apparatus to be governed in response to variations in speed and for stopping the apparatus in case of a failure in the supply of lubricating` oil.

These/and other objects, which Will be made apparent throughout the further des'cription of the invention, are attained by means of apparatus'embodying the features herein described and illustrated in the drawirgs accompanying and forming a part here- In thedrawings: Fig. l is a vertical sectional view of a geareddturbine apparatus equipped with a governing' mechanism embodying my invention.

Fig. 2 is a detail of the governing mechapiston 20 is imparted to the valve 9 through nism illustrated.

Fig. 3 is a fragmental illustration of an impeller forming. a detail of my invention.

Fig. 4 is a s1de elevation of the geared turbine apparatus, with a portion broken away to show details of the auto-stop valve. Flg. 5 is a sectional detail view showing a portion of the trip-mechanism. Y Y Y In the drawings I have'illustrated a reentry type of turbine' including a rotor element 3,'rotor blades 5, nozzles 4, .and reversing chambers 6, all of -which are enclosed within a stationary casing 7. Motive Huid,

hereinafter termed steam, is delivered to the nozzles 4 through a passage 8, which is controlled by a governor actuated valve 9. vAs shown, th rotor element 3 is mounted on a shaft 10, which is journalled in suitable bearings supported by a gear casing 11. A pinion 12 is shown mounted on ashaft 10 and in mesh with a driven gear 13, which is mounted on or operatively coupled to a shaft 14. The casing '11 encloses the gears 12 and 13 and forms a receptacle in which lubricant for thev gears'is contained.

The governing mechanism herein illustrated as an embodiment of my invention is operatively coupled toa sha-ft -10 at a pointv adjacent to the outboard bearing of the shaft. As shown, the governing mechanism includes a rotatable impeller 15 mounted directly on the projecting end of the shaft 10 and enclosed within a chamber 16, which is formed within a cylinder/217 and is separated from the major portion of the cylinder by means of a partition 18. During the operation of the turbine and consequently of the gears 12 and 13, lubricant is delivered through suitable passages, hereinafter described, to a port 19 formed in the end of the cylinder 17 around the shaft 1,0. The lubricant so delivered is acted upon by the impeller 15 and is forced voutwardly by centrifugal force, thereby creating liquid pressure within the chamber 16 which is proportional to the square of the speed of the impeller. This pressure is communicated to a' movable piston 20 through ports 21 formed within the partition 18. The piston 20 is located within the cylinder 17 and is adapted to move longitudinally of the cylinder in response to variations in lateral pressure to Which it is subjected. Inthe illustrated embodiment of the invention the longitudinal motion of the a ball thrust 22, a lever 23 and a link 24, which is shown as forming axpart of the valve stem 25 of the valve 9. A spring 26 surrounds the link 24 and operates between an adjustable abutment) "27 and a spring block 28 rigidly mounted on'the link 24. As shown the abutment 27 is screwed into a suitably tapped aperture formed in an extension of the casing 11 and is capable of beingk adjusted longitudinally of the link by being screwed into or out of the tapped aper-. ture. This arrangement forpadjusting the tension of the spring 26 permits the speed of the governor to be adjusted while the turbine and the governor are in opera-tion.

In Fig. 2, I have shown an end view of the impeller 15. As illustrated, the impeller consists of a hub 29 and integrally formed radially extending vanes 30. These vanes are shown stiffened by reinforcing ribs 31, which extend between the adjacent vanes and are preferably integrally formed with the vanes'. The ribs 31 are shown spaced from the hub 29 so as to provide liquid delivery passages' between them and the hub. rIhis arrangement is employed to prevent unbalancing of the impeller, and where the stifl'e'ning ribs are employed at points intermediate the lateral faces of the vanes, the apertures between the hub and the ribs provide adequate delivery spaces for the liquid, so that the vanes are equally effective on each side of the ribs. y

In the arrangement of gearing illustrated the casing 11 is adapted to be partially filled with oil to a level somewhat below the axis of the large gear 13. In order to deliver oil from this casing to the impeller 15 and .also to the bearings of the pinion 12 and gear 13, I have provided a splash passage 11a which is adapted to receive lubricant thrown outwardly by the rotation of the gear 13 and to deliver the lubricant so received to the bearings of the gears 12 and 13 and also tothe port 19 of the impeller casing 16. As shown, a passage 32 forms a means of communication between the splash chamber 111i and the port 19.

With the arrangement of apparatus illustrated, the turbine is started in the usual manner b slowly opening the hand 'throttle. As t e turbine comes up to speed the splash passage 11a receives oil which is delivered to the impeller 15. As the oil pressure occasioned by the action ofthe vimpeller increases, the piston 20 is moved outwardly and in opposition to the pressure of the spring 26. This moves the valve 9 toward its seat. The spring 26 may be adjusted so as to maintain the desired speed and consequently variations in the speed of the turbine, above or below the speed for which the governor is adjusted, will occasion corresponding variations in the pressure pumped by the impeller and will consequently occasion variations in the position of the valve 9, or in the amount of steam delivered to the turbine.

In the drawings I have shown an automatic stop valve 32 which may be of any of the well known types and which may be operated by means of a trip lever 33 through the agency of a lever 33a and link 34, etc.; the lever 33 being in lsuch a position as to be engaged and tripped by a centrifugal weight 33b which moves into an operative position whengthe gear 13 has exceeded a safe or determined speed. rIhe details of construction of the automatic stop valve 32, its operating mechanism, the trip lever 33 and the centrifugal weight for actuating the trip lever will be readily understood from Fig. 1 taken in connection with Figs. 4 and 5.

The valve 32 is arranged to shut off the delivery of steam to the valve 9 and therefore to the turbine when its actuating mechanism is tripped. It will be apparent that the automatic stop valve will operate to shut off steam to the turbine if the governing apparatus fails to perform its function. It will also be apparent that the governing apparatus cannot successfully perform its func-tion unless sufficient oil is delivered to the impeller 15 to maintain the requisite pressure .within the impeller chamber 16. For this reason a failure of the oil supply will operate to shut down the turbine since the pressure pumped by the impeller will, under such conditions, not be capable of counterbalancing the pressure of the spring 26 and consequently the valve 9 will be fully opened, thereby causing the turbine to exceed the safe or determined speed at which the automatic stop valvef is called into operation. i

A. slowing down of the turbine also causes a decrease 1n the pressure pumped by the impeller and thereby destroys the equilibriumof the forces acting on the piston 20. 'As a result, the spring 26extends and moves the piston toward the impeller chamber, thereby increasing the opening of the valve 9 and at the same time forcing lubricant out of the impeller chamber through the port `19 and in opposition to the pressure pumped by the impeller. As soon 'as the spring 26 is sufliciently extended to just counterbalance the reduced hydraulic pressure on the piston 20, the piston again comes to rest and holds the valve 9 in a corresponding position` until equilibrium of forces acting on the piston is again destroyed by a variation in the speed of the turbine, or by a failure in the supply of oil to the chamber 16.

It will be apparent that the impeller chamber 16 may receive oil from any source and that it may be included in a forced feed lubricating system in case such a system is employed in connection with the apparatus to be governed. I

In the drawings I have shown one end of the cylinder 17 open to the atmosphere by means of the slot through which the lever 23 projects. Iy have also shown this porti n of the cylinder provided with a drain-o passage 34 for delivering liquid leaking past the piston 20 back into the casing 11. It will be apparent that the piston 20 may be formed in a separate casing and may, if desired, be mounted directly on the link 24.'

With such an arrangementlubricant would lbe piped from the impeller chamber 16 vto the cylinder enclosing the piston 20.

In Fig. 3 of the drawings I have shown a fragmental sectional view of` an impeller which maybe employed where conditions are such that it is necessary to compensate for variations in the temperature of the liquid delivered to the impeller. It will be apparent that variations in temperature will occasion a variation inthe effective centrifugal force and consequently in the pressure pumped by the impeller. Asv a matter of fact these temperature variations are not excessive. under ordinary operating conditions, and it is found that the liquid delivered to the impellerwill in a short periodx of time reach its maximum limit of tem-- perature and maintain that temperature during the operation of the apparatus. Where conditions do not favor a relatively constant temperature of the liquid delivered to the impeller. I employ an impeller which will compensate for the variations in temperature by automatically increasing the tip speed of the`iu1pel1erv blades. One means for accomplishing this result is illustrated in Fig. 3. As shown, each blade of the impeller is built up of laminations having different coefficients of expansion. For example, the first lamination 36,which is rigidly secured to the hub 29 of the impeller. may be composed of copper or hard rubber or any other material having a high coefficient of expansion. Secured to the outer end of the lamination 36, I have shown a second lamination 37, which may be of any material having a relatively low coefficient of expansion, such for example as steel. The inner edge of the lamination 37 is rigidly secured to a third lamination 38, which like the lamination 36 is composed of material having a highcoefficient of expansion. It will, of course, be understood that the built up impeller blade will be so constructed as to prevent distortion when subjected to centrifugal force, or other external forces ordinarily encountered during its operation. With the arrangement illustrated, the expansion of the materials of high coefficient. of expansion is. in effect, multiplied, since the expansion of the lamination 36 is, in effect, added to the expansion of the lamination 38 in increasing the length of the impeller blade.

In F'g. 1` I have shown an additional feature` of my invention which may be'employed Where the governed apparatus (that is, the turbine) drives a pump or blower. As illustrated, the pressure pumped by the driven machine exerts a governing influence on the turbine. 'This is accomplished in the illustrated embodiment of the invention by providing a cylinder 40 on the spring supporting bracket 27a of the casing 11. The

cylinder encloses a piston 41, which may be subjected on one side to atmospheric pressure, but which is subjected on the other side to the pressure pumped by the driven machine. As shown, the cylinder 40 is so located withy relation to the spring 26 and the lever 23 that the hydraulic pressure transmitted to the piston 41 operates in opposition tothe pressure of the spring 26. This is accomplished by so locating the cylinder that its axis is substantially parallel `to the link 24 and the piston rod 42 is secured to an extension of the lever 23 by means of a link 43. The pressure pumped by the driven machine is delivered to the cylinder through a port 44.

With this arrangement of apparatus, a variation in the pressure pumped by the driven machine will vary the pressure opposed to the spring 26`and consequently will occasion a readjustment of the valve 9 and vary 'the speed of the turbine accordingly. If, for example, the pressure pumped by the driven machine exceeds the normal or determined pressure, the piston 41 moving to the left in the dra-wing will operate in opposition to the pressure transmitted by the spring 26 tol close the valve 9 more or less and thereby decrease the supply of motive fluid to the turbine. An opening of the valve 9 will be occasioned in a similar manner by a reduction of the fiuid pressure within the cylinder 40 below the normal or determined pressure.

In accordance with the provisions of the patent statutes, I have described 'and illustrated what I now consider to be the-preferred embodiment of my invention, but I desirev it to be understood that various changes, modifications, additions and omissions may be made in the apparatus illustrated without departing from the spirit and scope of the invention as set forth by the appended claims.

Vhat I claim is:

1. In combination with a turbine including a valve and a shaft. a pinion mounted on the turbine shaft, a reduction gear meshing with said pinion, an impeller driven by said turbine shaft, a receptacle for holding lubricant in which the gear normally dips, whereby the bearings for the pinion and gear are lubricated by oil splashed by said gear when the gear is rotated. means for collecting a portion of said splashed oil and delivering it to said impeller, a pressureresponsive device cooperating with said impeller and connected to said valve, and a yieldable resistance for opposing motion of the pressure-responsive device in response to pressure increases, the oil pressure developed by said impeller and the yieldable resistance cooperating to move the valve to control the admission of motive fluid to the turbine and thereby to govern the speed of the latter.

2. The combination with a mtor having a speed controlling governor actuated by fluid pressure in a lubricating system which is proportional to the speed of the motor and dependent upon the circulationl of lubricant so that the failure of the lubricating system reduces the pressure in the governor, and having a motive fluid valve actuated by the said governor and adapted to be opened only by a reduction in pressure in the governor, of an over-speed governor responsive to overspeeds of a motor-operated element for closing the motive fluid inlet when al failure of the lubricant supply effects a reduction of pressure in the speed controlling governor and a consequent increase in the speed of the motor.- c

3. In combination in an apparatus to' be governed, a motor, a driven gear, means for supporting a liquid in contact with the gear, a shaft driven by the motor, a pinion carried by the shaft and meshing with said gear, a pump driven by the shaft, a receptacle adapt ed to collect liquid elevated by said gear and to conduct the same tosaid pump, a valve for' controlling the admission of motive fluid to said motor, and means responsive to pressure produced by the pump for actuating sai-d valve. y

4. In combination with a turbine having an admission valve, a pinion driven by the turbine, a reduction gear meshing withn said pinion, an impeller mounted on the shaft of said pinion, a lubricating system including the saidgear for delivering liquid lubricant to said impeller, pressure-responsive means including an element movable in response to pressure of Huid developed by said impeller, mechanism arranged between said element and said admission valve, whereby, when the element moves in response to. increase of fluid pressure, a closing movement is imparted to said admission valve, and yieldable means acting on said mechanism for opposing movement thereof in response to increase ofpressure and adapted to move said mechanism to impart opening movement to said admissionl valve upon a decrease of Huid pressure.

' 5. In combination with an apparatus to be governed, an impeller mounted on a rotating shaft driven by said apparatus, means for deliveringliquid to said impeller, and pressure responsive means subjected to the pressure pumped by said impeller for controlling the delivery of actuating fluid to said apparatus, said impeller including com pensating means res onsive to changes in temperature of the'liquid, whereby liquid pressure is caused to vary uniformly with the speed of the apparatus regardless of operative thermal conditions of the liquid.

6. ln combination with an apparatus to be governed, an impeller mounted on a rotatable shaft of wsaid apparatus, means for delivering liquid to said impeller, pressure responsive means subjected to pressurepumped by the'impeller, and means actuated thereby for `controlling th operation of said apparatus, said impeller including vanes whose lengthI varies with the temperature of the liquid, wherebyliquid pressure is caused to -vary uniformly with the speed of the appa` ratus regardless f operative thermal conditions of the liquid.

7 The combination with a fluid-actuated engine and a lubricating system, of 'an impeller supplied with oil from said system and driven by said engine for developing pres-d sure of oil for governing the engine, said impeller including compensating means for maintaining pressures of oil in accordance with the speed of the engine under varying operative oil temperatures.

8. The combination with a power unit controlled by fluid pressure generated by a pump driven by the said unit,A of an impeller for the pump adapted to vary its capacity in response to thermal varia-tions of the iiuid,

so as to maintain uniform pressure when rotated at a constant speed regardless of the temperature of the fluid. v

Y In testimony whereof, I have hereunto subscribed my name this 15th day of April,

1918. HENRY F. SCHMIDT.

Witness:

C. W. McGrmm.

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