US1371243A - Method and means for regulating or controlling mechanism - Google Patents

Description

.I. M. HOPWOOD.

METHOD AND MEANS FOR REGULATING 0R CONTROLLING MECHANISM.

APPLICATION FILED APR. 21, I919.

Patented Mar. 15, 1921. 3 SHEETS-SHEET 1.

F I I3- 1- INVENTOR m wfir J. M. HOPWOOD.

METHOD AND MEANS FOR REGULATING 0R CONTROLLING MECHANISM.

APPLICATION F.lLED APR. 21,1919.

1,37 1 ,243, Patented Mar. 15, 1921..

3 SHEETS-SHEET 2- INVENTOR WMDM "1 W WITNESSES J. M. HOPWOOD.

METHOD AND'MEANS FOR REGULATING 0R CONTROLLING MECHANISM.

APPLICATION FILED APR. 21, 1919.

Patented Mar. 15, 1921.,

3 SHEETS-SHEET 3. FIEI-h. Fl {3.4. 1%,

- IIIIIII INVENTOR WITNESSES UNITED sures PATENT OFFICE.

JOHN M. HOPWOOD, OF DORMONT, PENNSYLVANIA.

Specification of Letters Patent.

Patented Mar. 15, 1921.

Application filed April 21, 19i9. Serial No. 291,779.

To all (0/2 0222- if may concern Be it known that I, JoHN M. Horwoon,

residing at Dormont, in the county of Allegheny and State of Pennsylvania, a citizen of the United States, have invented or discovered certain new and useful Improvements in Methods and Means for Regulating or Controlling Mechanism, of which Improvements the following is a specification.

In an application filed December 10th, 1917. Serial Number 206,479, I have described and claimed a method of and apparatus for retarding the movement of a regulating or controlling mechanism consisting of a rigid movable member and a flexible member in contact with the rigid member, the exposed surfaces of said mechanism being subjected to oppositely acting pressures. and movable on a change of one of said pressures, said method consisting of changing by the movement of the mechanism the area of contact of the flexible member with the movable rigid member an amount proportional to such change of pressure. It has been found in practice that when the pressures acting on opposite sides of the mechanism are small, as for example five pounds more or less, that with a change of even one half ounce in one of those pressures, there will be suiiicient movement of the mechanism to operate a transmitting mechanism. But when the oppositely acting pressures are large, as for example, two hundred pounds per square inch, a change of several pounds in one of the oppositely acting pressures will not cause a commercially usable movement of the mechanism.

The object of the invention described herein is to provide for the application of a small pressure to one of the members of such mechanism and of a small percentage of a high pressure to the other member by counterbalancing the large percentage of such high pressure. The invention is here= inafter more fully described and claimed.

In the accompanying drawings forming a part of this specification. Figure 1 is a view showing a construction of mechanism adapted to the practice of the invention; Fig. 2 is a sectional elevation of the portion of the mechanism shown to the right of Fig. 1; Fig. 3 is a view similar to Fig. 2 showing a form of mechanism operative by changes in the rate of flow of a fluid; Figs. 4 and '5 are sectional views illustrating certain modifications.

In the practice of the invention provision is made for subjecting one side of a flexible I diaphragm 1 preferably formed of metal, to a predetermined constant but low pressure, as for example five or six pounds per square 111011, more or less, while the opposite side of the diaphragm is in contact with a movable rigid or nonflexible member as a disk 2. A pressure generated by heat (as In a steam generator) or other means and which in practice will vary more or less, is so applied to the disk 2 as to act in opposition to pressure on the diaphragm. The pressure applied to the disk and diaphragm are so proportioned that under normal cond tions the diaphragm will be somewhat dished so that the area of contact of the diaphragm with the adjacent faces of the disk will be substantially less than that of the entire face of the disk. In case of an increase in the pressure applied to the disk, the latter will be shifted and thereby increase the area of contact of the diaphragm with the disk until the lower but constant pressure acting on the diaphragm will by reason of the increased area of contact between the two members, check the movement of the disk. In case the pressure acting on the disk drops, the pressure on the dia-' phragm will cause a further dishing of the diaphragm and consequent reduction of area of contact of the diaphragm and disk until the lowerpressure on the disk will counterbalance the higher constant pressure acting on a reduced area.

It will be readily understood by those skilled in the art that when the pressures acting on the disk and diaphragm respectively are small, 6. 9., five or six pounds. a small change in the pressure acting on the disk will produce a substantial movement of the latter 2'. e., one suliicient to operate a transmitting mechanism.

In order to utilize the sensitiveness of the mechanismwhen subjected to low pressures as above stated, when using the mechanism in connection with hi h pressures. provision is made for neutralizing or counterbalancing, in so far as action on the mechanism is concerned. all except a small percentage of the high pressure. A convenient construction to this end consists in connecting the source of high generated pressure v ber '10, one side of} which is :will beconsta-nt and equal to a predeter- 4 sure will .be equal tothe d-ifi'erencebetween minedsmall pressure, and the other pres such predetermined small pressure and the high pressure in chamber, at its predetermined IIOIIIliLlPOlIlt. In case of an 1n- 1 crease of the high generated pressure the disk 2 ,will 'bezshifted until by reason of ftheincr'ease in the area of contact of the diaphragm with the disk, thecon'stant 'pressure on-thedi'aphragm acting-through-this ance the'lincrease in the high generated pres-- increased area on the disk will, counterbals'ure; In case of a decrease inthe generated pressure, the constant pressure onthe diaphragm .will shift'the disk 2'in a direction to reduce the area of contact between the diskand diaphragm until the constant pressure acting on a reduced area 'willequa-l regardsgeifectiveness, the reduction of the I t v, I mentof the disk, leve r. and d aphragmfl;

In .case of a "decrease of pressurein {the generator, the action above described high generate dpressure.

A convenlent-means for? the invention consists in connecting a vapor gem normal pressure fin the generator or-other erator or other source of fluidpressure'to-a chamber 3, one wall of whichis'formed by a diaphragm 4 to which issecureda plate 5 provided with'a-knife-edge 6 preferably. formed on a'removabl-e plugv 6, as shown in Fig. 2 and adapted to bear ona'lever 7.

This lever which is fulcrumedratw8, carries 1 a weight or \VQI-ghtSfSufllC1I1t"tQ,,CO1111teI baIanceaIl but a small fraction of the high source. 'As-forexample, if the nornial pres sure in: the generator'or' other source and operating on the diaphragm 4is 250 pounds per squareincli, the lever 7 will be weighted o to counterbalance 245 pounds of such generated-fpressure and the ,additionaLfi'vepounds required to; completely coimterba'l:

ance the normal generated, pressure can -.be applied to thediaphragm 4 through astrut 9, and lever 7. I As shownin Fig- 2, one end ofthest'rut bearsv the lever and'on its opposite 'e'nd restadisk2 arran ed'in cham-' r ed b a dia hragm preferably formed of metal; am peripherally clam ed between .the an-" nular wall of the ch'am er and; the flange 11 on the lowerendof the shell .12. Within *this shell, is'maintai-ned a pressure suflicient with a predetermined area of contact between the diaphragm and disk to balance the difference between the normal ressure in 60 I'sure counterbalanced by the lever; -.Such

the generator and that portion 0 such pres:

pressure would under the conditions mentioned above, be approximately five. pounds. In the construction shown, aninverted cup 13 is arranged inthe. shell'which is filledacer or the} the counterbalancin'g pressures, z .of' the weightedleveraiid theconstant pres; r i sure operating'througha reduced area'willundsbut'the reducedtp'res i sure in the generator. I

high pressure opening through the. conduit the disk; and the conduit fluid from. a generator or other source of high fluid pressure, the pressure in the chamber 3 and acting on the diaphragm 4 will vary with changes of static pressure in with asuitable liquid, -and: air is forced through the valve 14 into the: cup thereby forming an air cushion normally exerting the required pressure of approximately five pounds per'square inch which is transmitted through the liquid to one side of the diaphragm forcing the opposite surface of'the' diaphragm into contact-with one face of the disk 2. In case of an increase of pressure in the generator, the lever 7 will'beraised thereby through the strut causing an upward movement of the disk 2 and an increase of {the area of contact of the disk with the generator. It will be understood that as jthearea'ofcontact between the diaphragm and 'disk increases progressively,- the con- 'stant pressure" in theshell will act vprogres sively to retard and" finally stop the movetion of area ofqcon't'act between the disk and equal not. 250 p The mechanism shown 11', Figs. "1 and: 2 will lie-operative by and in "0., those 'diaphra gm as the disk moves down, until.:,-Q "i I accordance with changes: in'a static-fluid pressure or byand; 1n accordance with changes in stat1c1presin. l*?ig. 1 through alpipe" 15 to a conduit- 16 in which -is .-a perforated disk 15?, the pipe conductingthe the conduit and also with changes in the posterior to sure and changes in therrate ofi-flow-of the fluid through a pipe or Iconduit, .d'ependent upon the connection of the "chamber 3 tea"generatororapipe-oreonduitthrough which the fluidiflows from. the

vgenerator; As for example, if theichjamber' .3 be connected to a conduit througha Pitot 115- rate, of flow of fluid through the conduit.

If --howeve r. the perforated disk 15 be omitted, the pressure'in the'chamberB will vary only with-changes in the static preslief-1fordisk 21. One of these chambers as 17 is so connected by a pipe 22 to a conduit 24 connected to a source of high fluid pressure that the pressure in said chamber will be substantially equal to the static pressure of v the fluid flowing through the conduit 24,

while the other chamber as 18 is so connected to the conduit as by a Pitot tube 22 that the pressure in said chamber will be substantially equal to the total pressure in the conduit, 2'. e., the static pressure plus or minus- (dependent upon the arrangement of the Pitot tube) the pressure due to the rate of flow of the fluid through the conduit. The disk or block 21 is so connected to the disk 2 of the movable device that the constant pressure acting on the diaphragm 1 will oppose the total pressure in the conduit, or in the construction shown will oppose the pressure in the chamber 18. In the arrangement shown, a bar 27 passing through the block 21 is connected by links including the turn buckles 26 toa bar 25 passing through the disk 2. v

The pressure in the chamber 17 and that portion of the pressure in the chamber 18 due to the static pressure in theconduit 24 will, of course, balance each other regardless of any change in the static pressure in the conduit; and, in initially adjusting the mechanism for operation, such a constant pressure is established in chamber 12 as will be suflicient, when acting on disk 2 through the diaphragm 1, to maintain, under normal rate of flow in the. conduit, the disk and the other parts moving therewith in the position in which all these movable parts are shown in Fig. 3; and there will obviously be no movement of these parts from this position so long as the rate of flow through the conduit remains normal. If however such rate offlow should change, as for example 7 drop, the constant pressure in the chamber 12 and acting on the diaphragm will cause it and the disk 2 to-move down thereby progressively reducing the area of contact between the disk and diaphragm, until by reason of the reduction of area, equilibrium is established between the constant pressure on the diaphragm acting on the reduced area and the lower dynamic pressure in' the chamber 18. If there should be an increase in the rate of flow, the disk 2 will be forced up causing an increase in the area of contact between the disk and diaphragmv 1, until by reason of such increase, the constant pressure in chamber 12 acting on the disk through the diaphragm will counterbalance the increased dynamic pressure in the chamber 18. As the movement of the disk 2' is effected only by and in accordance with changes in the rate of flow and is proportional to each increment of change in such rate, the construction shown in Fig. 3 is especially applicable for use in measuring the rate of flow of steam or other fluids under high pressure and can be so employed by connecting a suitable indicating or registering mechanism 28 to some member moving with the disk 2 as for example the bar.25. This registering mechanism which is secured to a suitable support 28 can be of any suitable construction whereby the movement of the bar 25 is transmitted to the movable index finger of the mechanism.

Inlieu of a diaphragm peripherally held as against movement and subjected to a constant fluid pressure as shown in Fig. 2, a construction similar to that shown in Figs.

4 or 5 may be employed. These constructions include a movable disk 2 and a member havv ing a curved surface adapted to bear upon the upper face of the disk and capable-of being flattened to increase the area of contact of the member with the disk. The em-' bodiment shown in Fig. 5 consists of a ball 29 formed of rubber or other suitable resilient material arranged in a shell 30 to bear upon the disk 2. In order to regulate the pressure to be exerted on the disk by the ,ball,--a follower plate 31 is arranged to bear on the ball and is adjusted by a screw or other suitable means to vary the pressure and consequently the area of contact of the ball on the disk.

In lieu of a ball, a tube 34 having at its lower end a spherical portion 33 formed of flexible material and secured to the shell 34 as shown in Fig. 4 may be employed. This tube is provided with an inlet valved pipe 35 for the admission of fluid under pressure dependent on the counterbalancing pressure required.

In order to utilize the movement follow ing a change in the generated pressure, in the construction shown in Figs. 1 and 2 for any purpose such as regulating the supply of fuel and the feed of air to the furnace or the discharge of products of combustion from the furnace, the lever 7, the movements of which will be the same as those of the disk 2, is connected by a rod 36 to a lever 37 on which is mounted a bell crank lever 43 having one arm connected tothe stem 38 of the movable member of the valve mechanism indicated at 39. This valve mechanism controls the flow of fluid under pressure to and from the opposite ends of the cylinder 40, which has its piston connected by rod 41 to a frame 42. The bell crank lever 43 has its other arm connected by a link 44 to a pivotally mounted post 45 adapted to be shifted by the frame 42, and

thereby reverse the movement of the valve. TlllS transmittingmechanism. which is preferred to be employed is fully shown and described in my application Serial No. 254.975, filed September 30, 1918.

In the adjustment of the mechanism described herein for operation, it is first determined how much or what proportion of the pressure on the underside of t e diaphragm 4 is to be neutralized, such pressure being' -on the disk or movable member 2. Fluid under pressure is then admitted into the cup 13 to act through the dia hragm 1 on the block 2 to counterbalance t e upward thrust of the strut 9.

The pressure above the diaphragm should .be such that the contact area of the diaphragm with the movable member may vary with a change of the upward thrust of the strut whether the change results from an increase or a decrease of the high pressure in the generator. e

Neither in the construction of the apparatus nor in the admission of fluid pressure to the cup is any account taken of the area of contact of the diaphragm on the disk or block 2. It is only desired to counterbalance the u award thrust oi the strut and this may be efl ected by so constructing the apparatus that counterbalancing is efl'ected by a low pressure acting on a diaphragm having a large area of contact with the block or a higher pressure and a smaller area of contact between the diaphra and block. 7

It will be readily un' erstood from the foregoing that the term pressure which when used in connection with fluids generally signifies pounds per unit of area, 1s not correctly descriptive when referring to the counterbalancing operation and 'hence the term force has been employed todesi ate the counterbalancing of the thrust o the strut on the block or movable member.

I claim herein as my invention:

1. The method of operating-a regulatin or controlling mechanismv consisting of a movable member and a flexible member in contact with the movable member, which consists in so applying a constant pressure to the flexible member that the two members shall have a substantial area of contact, the one with the other, utilizing this constant pressure and a second pressure to counterbalance a high ressure and by the movement of the mec anism due to a change in the high pressure, changing the area of contact between the members of the mechanismthereby restoring equilibrium between the pressures acting oppositely on the mechamsm.

2. The method of operating regulating or controlling mechanism which consists in "counterbalancing a predetermined percentage of a predetermined high pressure, ap-

plying the unbalanced portion of such high pressure to one side of the movable member of a mechanism consisting of such member and a flexible member in contact with the movable member, applying to the flexible member a constant pressure adapted with a properly "proportioned; area of contact between the members of the mechanism to counterbalance the percentage of'the high pressure applied to the movable member,

and by the movement of said mechanism due to a change in the high pressure changing the area of contact of the members of the mechanism and thereby impeding the movement of the mechanism caused by such change of pressure.

3. A mechanism which consists in a chamber having a movable portion adapted to be subjected on one sideto a high fluid pres-' sure, means for counterbalancing a portion of the high pressure, and means for counterbalancing theremainder of such high pres.- sure, consisting of ai inovable disk and a flexi? ble member arranged in contact one with the other so that a movement-of one of them will change the area of contact, and means for applying .a pressure to the flexible member adapted when the high pressure is normal to supplement the first counterbalancing means.

4. A mechanism having in combination a movable element adapted to be subjected on one side to a relatively high pressure, a

yielding means operating on the opposite side of the movablemember and adapted to exert thereon a ressure less than the high pressure, a'mem er movable with the said. element a flexible member in contact-with the movable member, the movable and flexible members being so arranged thatbn'a 'movement of either, the normal area of con-- tact between them will be varied and means 11 for applying a yielding pressure to the flexi-I ble member in a direction tooppose the relatively high pressure on the movable element.

5. A mechanism having in combinationv a movable element adapted to be subjected on one side to a relatively high pressure, a lever bearing on the opposite side of the movable element and subjected to a pressure suflicient to counterbalance a portion of the relatively high pressure, a movable member, means fortransmitting movement in-' terposed betweenthe movable member and the movable element, a flexible sheet peripherally supported in such manner that adjacent surfaces of the sheet and movable member will be in contact for a portion of the areas of such surfaces and means for applying a constant yielding pressure to the side of the sheet opposite that in contact with the movable member. a

6. The method of operating the movable member of a motor mechanism which consists in neutralizing the action of a portion of a normally predetermined but variable pressure, applying a force equal to the unneutralized portion of such variable pressure to one side of the movable member of the motor mechanism, applying to the opposite side of the movable member a force equal to that of the unneutralized portion of the variable pressure and by a movement of the movable member due to a change in the variable pressure restoring the equilibrium between the forces acting oppositely on the movable member.

7 The method of operating the movable member of a motor mechanism which consists in neutralizing the action of a large fraction of a normally predetermined but variable high pressure, applying a force equal to the unneutralized portion of such variable pressure to one side of the movable member of a motor mechanism, applying to the opposite side of said member a force equal to the normal difference between such high pressure and the neutralized portion thereof and by a. movement of the movable member due to a change. in the high pressure restoring equilibrium between the forces acting oppositely on the movable member.

8. The method of operating a registering or controlling mechanism embodying a movable member which consists in applying to one side of said member variable high pressure, applying to said member two pressures operating to normally counterbalance the high ressure and by a movement of the member no to a change in the high pressure restoring equilibrium between the high pressure and the counterbalancing pressures.

9. The method of operating a re istering or controlling mechanism embodying a movable member which consists in neutralizing all but a predetermined portion of a constantly acting but variable high pressure, applying the unneutralized portion of such pressure to the movable member applying an oppositely acting pressure being approximately equal to the unneutralized portion of the high pressure, and by a movement of said member, due to a change in the variable high pressure, restoring equilibrium between the pressures acting oppositely on said member.

In testimony whereof I have hereunto set my hand.

JOHN M. HOPWOOD.

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