US2645237A - Governor head vibration dampener - Google Patents

Description

y 1953 B. E. WHEELER GOVERNOR HEAD VIBRATION DAMPENER Filed July 11 1951 INVENTOR.

Patented July 14, 1953 icovER oa HEAD VIBRATlQN. n MPENEa Byron E. Wheeler, San Francisco, Calif., assignor to The Pelton Water Wheel Company, a corporation l i Application July 11, 1951', Serial No. 23 ,229

" '6 Claims. (Cl..137'-5'6) My invention relates primarily to speedreg sponsive governors utilized, among other things; in connection with the regulation of the operation of hydraulic turbines such as water wheels connected to electrical generators. Governors utilized in this environment are responsive to rotational speed by the provision of weights or fiyballs which occupy different positions in ac cordance with different speeds, and are efiective through a hydraulic mechanism to provide a speed responsive control. The actual movement of the flyballs or centrifugally responsive weights is extremely small, being of the order of several thousandths of an inch, and is resisted usually by a strap spring of very carefully'calibrated characteristics; A governor of this general construction is disclosed in the patent to ManiousGottlieb No. 2,237,780 issued April 8, 1941.

In the practical installation of such a governor, it has been found that under someconditions of regulation the unbalanced valve which releases the operating fluid from the hydraulic circuit, tends to bounce on its seat, to surge and tovibrate in such a fashion as not only to disrupt theiinely regulated governing of which the structure is otherwise capable, but alsoseemingly to induce even further surges and changes. 7 Consequently the speed regulation of the system "varies over an extremely wide and even destructive range.

For example, the ordinary governing range is only a fraction of one per cent of the desired speed, for example one hundredth of one per cent of the desired speed, and some small variation in that amount of regulation is tolerated. When the vibrational surges occur, and they seem to occur somewhat at random orat least in response to a variety of conditions which have not yet been finally established, the speed range isnot kept within the desired onehundredth of one per cent and does not vary a mere fraction of one per cent or so, but can vary fifteen or twenty per cent from the desired normal. Such a variation is so great and occurs withsuch random freunison.

' I 2 head "without unduly reorganizing the general setup. oi thegovernor head.

' A stillfurther object of the invention is to provide'a means forpreventing the erratic'behavior of governors; v l

Astill further object of the invention is to pro vide a vibration dampener which operates in several difierent ways to preclude the existe deleterious vibration in a governor head.

Other objects, together with the foregoing; are attained in the embodimentoi the invention described in the accompanying description and il-v lustrated in the accompanying drawing in which:

Figure 1 is a cross section on a' diametrical plane of a governor head of the general type shown in theflabove mentioned patent, but also incorporating the vibration dampen'er' of my inventi'on, parts of the structure being shown in elevation.

Figure 2'is a crosssection similar to Figure 1 but showing the various parts to an enlarged scale, portions brine figure being broken away toreduce itssize, I r

The; governor head is usually installedin connection with a regulating mechanism not com.- pletely shown but incorporated at least in part in a housing 6, carrying a drivinggear 1 connecting to the primemover mechanism to be governed; for example, to a hydraulic turbine. The gear I revolves at a speed proportional to the speed of theturbine. The gear 1 is in mesh with a driven pinion 8 within the casing. 6 and mounted on a drive tube 5). The drive tube is mounted in the housing 6 betweenappropriate anti-friction bearings H and. i2, and, receives hydraulic fluid through the lower end of a central passage 13 from a suitable regulating structure which is not part of the present. invention and is therefore not .disclosed in detail. Suffice me .say that the flow of hydraulic fluid through the tube!) is to be regulatedpursuant to the speed of rotation of theftubef 9 which itself is proportional to the speed of rotation of the prime mover. Adjacent its 'upper end the, drive tube 9 'isiexpanjded to provide a rotating yoke l6 comprised of several different parts all revolving in A governorstrap I] spans the yoke diametrically'a'nd is held in position by suitable fastenings l8 passing through the yoke and through an appropriate clamping ring I9. Fixed on the strap 'l-l are'flybalhweights '21 and 22", arranged so nce. of

3 or deform the strap ll against its inherent resiliency. The ofiset center 23 of the strap is therefore buckled upwardly a fraction of an inch as speed increases.

The upward movement of the strap is resisted by a spring 26 coaxial with the tube 9 and interposed between a washer 21 and a plate 28. The washer 21 is held in position by a nut 3| engaging a central bolt 32 passing through the strap whereas the plate 28 is mounted to rock on the lower end of a pointed adjusting screw 33 passing through a dome 34 included in the revolving yoke IS. The effect of this assembly is to urge the strap ll downwardly against the upward urgency imposed upon it by the outward movement of the weights 2| and 22 as speed increases.

The motion of the strap I1 is utilized to affect the governing flow of fluid through the central passage I 3 in the drive tube 9. The lower end of the bolt 32 terminates in a cup 4| conveniently located within the strap offset 23 and having a depression 42 in which the needle nose 43 of a central spindle 44 is socketed. The spindle 44 at its opposite end is enlarged to provide a partly conical head 46 against which a valve disc 41 can rest. The valve disc is also large enough to overlie and upon occasion to seat upon the upper knife edge 48 of a valve seat 49. This seat is a separate hollow body pressed into the upper end of the drive tube 9 and in effect forms a continuation thereof. The valve disc 41 when in seated position on the valve seat 49 prevents fluid flow therebetween. But when the valve disc 41 is lifted from the valve seat 49 flow can take place through the interior passage l3 of the drive tube 9. The arrangement is such that the valve disc 41 is freely movable with the spindle 44 until it abuts the seat 48. To assist in locating the valve disc 41 properly with respect to the seat, the spindle 44 pierces a centering or positioning diaphragm which is a flexible metal disc extending from the spindle and laterally confined between the circular cylindrical walls 52 of a bore in the yoke l6. Within limits the centering diaphragm is axially held by a retaining collar 53 secured by fastening bolts 54.

The centering or positioning diaphragm isdisposed next to the valve disc 41 and next to the centering diaphragm 5| is a spacer washer 56. In accordance with my invention, I locate in a position surrounding the spindle 44 and next to the spacing washer 56 a rubber dampening ring 51. The rubber cushion 51 is in the shape of an annulus and is preferably formed or cut from material having considerable internal friction or hysteresis, so that it has the property of converting small amounts of energy. The cushion 51 is placed in a reasonably tight sliding frictional engagement with the spindle 44 so that in addition to deformation of the cushion 57 within the material thereof, any displacement of the cushion axially along the spindle 44 results in a frictional drag which serves also to convert motion energy into heat. The precise material of the cushion 51 is not critical, although it is preferably fabricated of natural or synthetic rubber or like deformable and non-resonant substance.

Resting 0n the cushion 51 is a ring 6| preferably of metal freely slidable on the spindle 44 and in complete abutment with the cushion 51. The ring is disposed at one end of a helical spring 62 and serves as a guide therefor. The other end of the spring 62 is guided by a keeper 63 surrounding a reduced portion of the spindle 44 and held in position against axial displacement (at 4 least in one direction) by a locking washer 64 seated in a recess in the keeper and also in a groove in the spindle 44.

In the normal assembly of this structure, the dimensions of the parts are such that it is necessary to compress the spring 62 and to place the cushion 51 under a compressive load before the washer 64 can be snapped into location. Under usualconditions therefor the spring 62 serves to force the cushion 51, the washer 56, the centering diaphragm 5 I, and the valve disc 41 against the enlarged head 46 of the spindle. The amount of force exerted is substantial so that under customary conditions of operation the assembly acts virtually as though it were a solid structure. In other words, when the strap center 23 moves upwardly, for example, against the urgency of the spring 26, the valve disc 41 and the entire assembly likewise lifts simultaneously therewith, being moved by the hydraulic pressure fluid to provide an enlarged annular opening between the valve seat 49 and the valve disc. However, in the event aforce tending to set up a, vibration occurs, the extra hydraulic pressure within the interior of the valve seat 49 is suflicient to lift the valve disc 41 slightly against the yielding resistance of the cushion 51, even though the spindle 44 does not move and does not in any way move the strap 23. In this way, under a temporary excessive force the valve disc 4'! lifts and then drops slightly to relieve the force by slightly deforming the cushion 51 without in any wise disturbing the rest of the governor system and without, therefore, setting up or maintaining a vibrational characteristic. The cushion 51 not only permits the disc 41 to move upwardly, but likewise due to its deformation and due to any frictional sliding there may be on the spindle 44 absorbs (converts to heat) the energy involved and in effect, therefore, damps out the disturbance so that the system cannot 'be set into vibration. In practice it has been found that with this arrangement, minor disturbances which otherwise induce very severe disruptions in the governing system are damped out virtually at their source and are not permitted to set up and continue as vibratory phenomena. "The governor head consequently retains its ability to govern within extremely close limits.

What is claimed is:

1. A governor head vibration dampener comprising a drive tube rotatable about an axis and terminating in a valve seat concentric with said axis, a yoke on said drive tube symmetrical about said axis, a governor strap symmetrical about said axis, fasteners connecting the ends of said strap to said yoke, weights on said strap, a first spring interposed between and engaging said yoke and said strap, a spindle, one end of said spindle engaging said strap adjacent said first spring, a head on the other end of said spindle, a valve disc slidable on said spindle and adapted to seat on said valve seat, a helical second spring surrounding said spindle, a washer abutting one end of said second spring and fixed with respect to said spindle. a ring slidable on said spindle and abutting the other end of said second spring, and a rubber cushion frictionally engaging said spindle and interposed between said ring and said valve disc.

2. A governor head vibration dampener comprising a drive tube terminating-in a valve seat, a yoke on said drive tube, a governor strap spanning said yoke, weights on said strap, a first spring interposed between said yoke and said strap, a spindle adjacent one end of said first spring and engaging said strap, a head on the other end of said spindle, a valve disc slidable on said spindle and adapted to seat on said valve seat, a positioning diaphragm secured to said yoke and pierced by said spindle, a rubber cushion frictionally engaging said spindle, and a, helical second spring for urging said rubber cushion and said diaphragm and said valve disc against said head.

3. A governor head vibration dampener comprising a drive tube terminating in a valve seat, a speed responsive mechanism driven by said drive tube, a spindle movable toward and away from said valve seat by said speed responsive mechanism, a valve disc movable on said spindle toward and away from said valve seat, a spring for urging said valve disc to move in one direction along said spindle, and an energy absorbing cushion interposed between said valve disc and said spring.

4. A governor head vibration dampener comprising a valve seat, a speed responsive mechanism, a spindle movable toward and away from said valve seat by said speed responsive mechanism, a valve disc movable on said spindle toward and away from said valve seat, a spring for urging said valve disc to move along said spindle toward said valve seat, and an energy absorbing cushion interposed between said valve disc and said spring.

5. A governor head vibration dampener comprising a valve seat, a speed responsive mechanism, a spindle movable toward and away from said valve seat by said speed responsive mechanism, a head on said spindle, a valve disc movable on said spindle toward and away from said valve seat, a spring for urging said valve disc to move along said spindle into abutment with said head, and an energy absorbing cushion interposed between said valve disc and said spring and frictionally slidable on said spindle.

6. A governor head vibration dampener comprising a valve seat, a speed responsive mechanism, a spindle movable toward and away from said valve seat by said speed responsive mechanism, a head on said spindle, a valve disc movable on said spindle toward and away from said valve seat, a spring for pressing said valve disc against said head with a predetermined force, and a rubber cushion interposed between said valve disc and said spring and subject to said force.

BYRON E. WHEELER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 164,661 Eberhardt July 12, 1904 1,764,991 Siebs June 17, 1930 1,935,318 Hawxhurst Nov. 14, 1933 2,298,720 OFarrell Oct. 13, 1942 2,311,110 Johnson Feb. 16, 1943 2,332,910 Gottlieb Oct. 26, 1943 2,431,687 Drake Dec. 2', 1947

Images