US2256963A

US2256963A - Hydraulic governing apparatus

Info

Publication number: US2256963A
Application number: US365236A
Authority: US
Inventors: Henry F Schmidt
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1940-11-12
Filing date: 1940-11-12
Publication date: 1941-09-23
Anticipated expiration: 1958-09-23

Description

Sept. 23, 1941. H. F. SCHMIDT 2,256,963

BYDRAULIC GOVERNING APPARATUS Filed Nov. 12, 1940 .M amp dwen nw l u m INVENTOR ENRY F ScHMm BY @fiM m I1 H J I 3 n 7 Win. i m I, I 5 IL 2: \I 1 mm 7 a 1, a a E 0W .EHH

ATTORNE Patented Sept. 23, 1941 wire ST TEE m OFFICE HYDRAULIC GOVERNING APPARATUS Henry F. Schmidt, Lansdowne, Pa., assignor to Westinghouse Electric & Manufacturing Com-, pany, East Pittsburgh, Pa., a corporation of Pennsylvania Application November 12, 1940, 'SerialNo. 365,236

7 19 Claims.

The invention relates to hydraulic governing apparatus and the like and it has for an object to provide therefor improved means, for

In the patent of Bryant, No. 2,035,689, granted March 31, 1936, there is disclosed and claimed 'a reverse flow impeller, or centrifugal device resisting escape of liquid, operating to secure modification-of liquid pressurein a space so'that the pressure varies as a function of the speed of the impeller. The:'space-is supplied with liquid from a suitable source by means of an orifice,

and escape from the space, except for leakage,=v

can occur only through the impeller, with 'the result that the latter determines the pressure in the space so that such pressure may be used for governing purposes. This arrangement is sometimes subject to the objection of pressure fluctuations or variations due to variations in 'If there is a this effect of leakage variation, the now should be made large in relation to any anticipated leakage; however, with the single passage shown' in the patent, increased flow can be had only with variation in the effectiv radial length of the column centrifugally resisting escape, and

this introduces a variation in the pressure and speed relation. To overcome this objection, I provide an impeller wherein the flow may be so large in comparison to th leakage that any ,variation in the latter will not affect the pressure, and large variations in flow may occur with only negligible change in effective radial length of the column resisting escape, More particularly, I provide an impeller body having an axial 'bore and a plurality of passages connecting the space thereabout with the bore. Also, each passag preferably has its discharge end bounded by a ridge so that, as liquid flows over the latter, centrifugal force immediately,

effects outward movement of such escaping liquid toward the wall of the bore, the body having adequate escape openings to prevent liquid accumulating in the bore and affecting in any way the character of discharge from the tubular portions; and, as the aggregate ridge peripheral extent is relatively large, very substantial variations in flow :can occur without any appreciable change "in the thickness of theoverflowing crest layer, with th result that'the-flow can change over a wide range without changing the :radial column length of liquid setting up centrifugal resistance to escape and, therefore, without change in pressure-on account-of column length variation.

A further object of the invention-is to provide a centrifugal fluid relief device for-a hydraulic governor comprising a rotary 'member having a discharge bore and a plurality of relief passages discharging thereinto and distributed circumferentially of the'member.

Another object of the invention is to provide a centrifugal 'relief device for liquid and ineluding one ormore passages formedin a rotary member so that the discharge end of each passage is nearer :to the axis of the member than its outlet end and is located between the latter and th axis together with aridge bounding the discharge end of each passage to provide for liquid issuing from the discharge end assuming a crest formation to minimize the thickness of the discharging -or overflowing liquid layer.

These and :other. objects are effected, by the invention as will be apparent from the following description and claims taken in connection with the accompanying drawing, forming a :part of this application, in which: a

Fig. l is a longitudinal sectional view of a turbine equipped with a hydraulic governing system. which is provided with the improved impeller 7 Fig. 2 is a detail axial sectional view of. the

impeller; j q Fig. .3 is a sectional view taken along the line IIIIII of-Fig. 2; and, f

at It; operating to provide, in the enclosed space M, liquid under pressure varying substantially as the square of the speed of the turbine rotor l5 to which the impeller is attached.

The space, 14 includes the primary pressure chamber it formed in the structure I? ofithe it being connected tothe structure U by means of a bellows or sylphon element 20, and a spring 2| exerts its force on the abutment IS in a direction opposite to that of the fluid pressure force, one end of the spring being connected to suitable speed changer mechanism 22. The abutment i9 is associated with any suitable means eifective to amplify changes in impeller pressure.

By way of example, the amplifying or transforming means associated with the pressure abutment I9 may comprise a cup valve 24 arranged in covering relation with respect to the ecape port 25 of the pressure space 26 supplied with liquid under pressure by means of the orifice 21 from any suitable source of pressure. The pressure space 26 also includes the pressure chamber or space 28 of a pressure-responsive device, at 29, of the servo-motor, changes in pressure in the space 26 resulting in operation of the pressureresponsive device, at 29, to bring about operation of the pilot valve 30 of the servo-motor to control the admission and exhaust of motive fluid to the operating cylinder 3| to'secure movement of the operating piston 32 to adjust the admission valve, movement of the operating piston being transmitted through the follow-up mechanism, at 33, to change the force on the spring 34 incident to such movement of the operating piston so that movement of the latter may be terminated when equilibrium is again restored on the pressureresponsive device, at 29, with the pilot valve in neutral cut-off position.

The impeller, at I3, is comprised, for example, by a cylindrical body 31 attached to the rotor I 5. A housing structure 38 has spaced annular seals 39 fitting the periphery of the body 31 so as toprovide an annular portion l4a of said space l4. Any suitable means may be used to supply liquid to the space M so that the liquid pressure therein may depend upon the resistance of the centrifugal escape means hereinafter described. For example, there is provided, adjacent to the body 31, a centrifugal pump, at 40, driven by the rotor l and providing a suitable source of oil under pressure for any desired purpose, this source being connected by means of an orifice 4| to the space M.

Resistanceto escape from the space W1 is provided by a pluralit of passages 42 formed in the body 31 and affording communication between the encompassing space |4a and the interior bore 43 having a wall 43a. The inner end of each passage 42 is bounded by a ridge 44 extending from the bore wall to provide for discharge of liquid from each passage in crest formation. Preferably the passages 42 and the ridges 44 are provided by tubular members 45.

The inner ends 46 of the ridge portions 44 are formed so that the discharge edges are included in a cylindrical surface which is coaxial with the cylindrical periphery of the body 31. Liquid is discharged from the bore by means of suitably located passages 41. Also, maintenance of atmospheric pressure in the bore is assured by means of the vent passages 48,

The ridge portion 44 of each passage 42 provides for liquid issuing from the latter taking a crest formation, with the result that a minimum thickness of the discharging layer will be maintained. If, as diagrammatically shown at the left in Fig. 4, the passage did not have its discharge end bounded by a ridge, then fluid after discharge would tend to accumulate and introduce considerable variation in thickness of the liquid layer at the discharge end of the passage. This objection is avoided by means of the ridge 44 bounding the discharge end of the passage, as will be seen from the passage at the right of Fig. 4. Just as soon as liquid passes over the crest of the ridge, centrifugal force is then effective to move such liquid outwardly radially, with the result that any tendency of liquid to accumulate on the wall 43a would not cause variations in thickness of the crest layer. Thus, by providing a ridge to give a crest formation to the liquid issuing from the centrifugal relief passage, the discharging liquid layer is kept very thin and minimum variations in thickness thereof occur with variations in flow with the result that the radial length of the column of liquid giving centrifugal resistance to escape is kept substantially constant and pressure pulsations due to column length variations are avoided.

Due to the provision of a plurality of passages distributed circumferentially about the body 31, it is assured that any variations in pressure in the space encompassing the body will be averaged, thereby making operationof the device more uniform. Furthermore, by the use of a suitable number of distributed passages, it becomes possible to provide for such relatively large flow that variations in leakage are relatively small in comparison thereto, the wide variations in flow taking place without any appreciable variation in radial length of the column of liquid in the passages resisting centrifugally the escape of fluid. Fluid escaping from the inner or ridge ends of the tubular portions 45 overflows the discharge edges 46 in a very thin crest layer for the reason that the aggregate or peripheral extent of all of the edges 46 is relatively large in comparison to flow, so that very large changes in flow may occur without any appreciable variation in thickness of the crest layer and consequently variation in effective length of the hydraulic column resisting escape centrifugally.

As shown, the escape passages 41 are distributed about the body 31 and communicate with the bore adjacent to the peripheral bore wall, and these passages in the aggregate have a flow area substantially larger than that of the passages 42 so that liquid may escape from the bore as rapidly as it enters, thereby preventing any accumulation or tendency thereof to disturb the pressure conditions created by the passages 42.

While the passages 42 may be formed in any suitable'manner, I prefer to have the body 31 provided with a circumferential series of radial openings 50 for the reception of the tubular elements 45 which provide the passages 42 as well as theinner tubular extensions or ridges 44.

While the invention has been shown in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and it is desired, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What is claimed is:

1. In a hydraulic governor for controlling the speed of a rotary member, means for maintaining a pulsation-free,pressure dependent upon speed of the rotary member and including a centrifugal fluid relief passage formed in the latter, said passage having its discharge end disposed nearer to the axis of the rotary mem.

her than its inlet end and located between the latter and the axis, and a ridge carried by the rotary member and bounding the discharge end of the passage.

2. The combination as claimed in claim 1, wherein the crest of the ridge is located in a cylindrical surface coaxial with the rotary member.

3. In a hydraulic governor for controlling the speed of a rotary member, means for maintaining a pulsation-free pressure dependent upon speed of the rotary member and including a plurality of centrifugal fluid relief passages formed in the latter, said passages being distributed circumferentially about the rotary member and each passage having its discharge end disposed nearer to the axis of the rotary member than its inlet end and located between the latter and the axis, and ridges carried by the rotary member and bounding the respective discharge ends of the passages.

4. The combination as claimed in claim 3, wherein the crests of the ridges are located in a cylindrical surface coaxial with the rotary member.

5. The combination with a rotary member having a cylindrical portion, of apparatus providing liquid under pressure dependent upon speed of the member and comprising means, including the cylindrical portion of the rotary member, defining a space for the liquid under pressure; said space having an annular portion whose inner boundary wall is provided by said cylindrical portion of the rotary member; means providing for escape of liquid from said space and including a bore formed in the cylindrical portion and a plurality of passages formed in the latter with their outer ends communicating with the annular portion of said space and with their inner ends communicating with said bore; ridges carried by the rotary member within the bore and bounding the discharge ends of the passages; and means for supplying liquid to said space so that the pressure therein depends upon the escape resistance provided by said escape means.

6. The combination as claimed in claim 5,

wherein the passages are distributed circum entially thereof and wherein the crests of the ridges are in a cylindrical surface which is coaxial with the rotary member.

10. The combination with a rotary member having a cylindrical portion, of apparatus for developing liquid under pressure dependent upon speed of the member and comprising means including the cylindrical portion of the rotary member providing a space for the liquid under pressure; said space having an annular portion whose inner boundary wall is provided by said cylindrical portion of the rotary member; means for including an orifice for supplying liquid from a pressure source to said space; means providing for escape of liquid from said space including a bore formed in the cylindrical portion, a plurality of passages formed in the latter with their outer ends communicating with the annular portion of said space and with their inner ends communicating with said bore, and escape openings formed in the cylindrical portion and communicating with the bore adjacent to the peripheral bore wall; said lastnamed means including ridges carried by the cylindrical portion and bounding the discharge ends of said passages and allot the crest por-- tions of the ridges being in a cylindrical surface which is coaxial with the cylindrical portion; and a passage formed in the rotary member and affording communication between the bore and the atmosphere.

HENRY F. SCHMIDT.