US2273103A - Measuring and control apparatus - Google Patents

Description

Feb. 17, 1942.

T. R. HARRISQN MEASURING AND CON'IiROL APPARATUS Original Filed Sept.

a R \M w 1? w 2. F w V I h l .P .2 kl m m w 1 r I N x wi lfl lhv I N... H. m 1 m K & m. N H S. fw s I". m 7. A E v m E .H I w W m 1] I z mv L m0 m6 Q w F, I- n E .u 7.0 .m q 8 L ow a a mo 1 N m 0 w 0 mm mm m0 h I 0 ll 4w .3 0 mfl 0 46 0 THOMAS R. HARRISON AT'roNEY Patented Feb. 17, 1942 MEASURING AND CONTROL APPARATUS Thomas R... Harrison, Wyncote, Pa., assignor to The Brown Instrument Company, Philadelphia,

Pa., a corporation of Pennsylvania Original application September 11, 1935, serial-no.

40,103. Divided and this application January 21, 1939, Serial No. 253,135

(o1. zoo-14) 3 Claims.

The general object of the present invention is to provide an improved control mechanism including novel means for effecting control actions which are a joint function of two quantities varying independently of one another. specific object of the invention is to provide an improved control system for a liquid heating furnace, comprising novel and effective meansv A more a part of this specification. For a better understanding of the invention, however, its advantages, and specific objects attained with its use, reference should be had-to the accompanying drawing and descriptive matter in which I have illustrated and described a preferred embodiment of the invention.

The one figure of the drawing is a diagrammatic representation of an oil still and associated fuel control means.

In the drawing, I have illustrated the use of the present invention in regulating the supply of fuel to an oil still or heater S, in which the fluid heated moves in the direction indicated by the arrow through a tube T which includes convolutions within and absorbing heat from the still furnace. As shown, the fuel supply is regulated by adjusting a valve J in the furnace fuel supply pipe J". The valve J is of the fluid pressure motor type, and is given opening and closing adjustments by increasing and decreasing the control pressure transmitted to the pressure chamber of the valve J by a pipe'J The pressure in the pipe J is varied by the adjustment of a so-called flapper valve J toward and away from the bleed orifice nozzle J of an air controller unit device JA, continuously receiving air through a restricted orifice J in a compressed air supp y p pe J The air controller unit or device JA may be of any one of various known types, and as shown is of the type illustrated in Patent Nos. 2,124,946 and 2,125,109, each granted July 26, 1938, on a joint application of F. W. Side and myself.

tion of the control device JA is unnecessary,

since in respect to that device, the present invention is only with the means through which its flapper valve J is adjusted in response to variations in the temperatures to which two temperature responsive elements es and et are respectively exposed. a

As shown, each of those elements is the bulb of an expansive fluid thermometer. The bulb es is subjected to the temperature in a selected portion of the furnace, and the fluid pressure de-" pendent on that temperature is transmitted by a capillary tube or pipe e from the bulb es to the stationary end of a Bourdon tube EA. The latter has its movable end connected, and giving angular movement, to an axial shaft-E which carries an arm E The bulb et is shown as subjected to the temperature at which the oil heated passes away from the furnace, and the corresponding fluid pressure is transmitted from that bulb through the corresponding capillary tube or pipe connection e, to the stationary end of a Bourdon tube EB which has its movable end connected to a corresponding axial shaft E' carrying an arm E The two Bourdon tubes EA and EB may be, and as shown are, identical in construction. Furthermore, angular'adjustments Further reference to the construction and operaof each arm E effect angular adjustments of the control valve J of the air controller unit JA, but the'two arms iii eflect adjustments of the said valve J through different operating instrumentalities.

The oscillating arm E of the device EAis connected by a link E to a depending arm of a bell crank lever GA forming a part of the unit JA, and turning about the stationary axis of a fulcrum pivot GG. A second and horizontally disposed arm of the lever GA, is connected by a suspension link G to one end of a floating lever FA. The other end of the floating lever FA is connected by a suspension link G tothe horizontally disposed arm of a second bell crank lever GB, also mounted to turn about the axis of the fulcrum pivot GG, and having its angular position adjusted as hereinafter described, by means including a link 1). As shown, the arms of the levers GA and GB to which the links G and G are connected, extend in generally opposed horizontal directions away from the axis of the fulcrumpivot GG, when said levers are within their. normal range of adjustment.

Movements of the lever FA efiect adjustments of the valve J of the device, A, through a lever K which is pivoted to' turn about a relatively stationary pivot included in the unit JA. Said lever K has one arm connected to the lever FA, between the ends of the latter, by a pivot pin FK, and has a second arm carrying a pin K; The valve J of the unit JA is biased for movement into engagement with the nozzle J of the device JA, to thereby prevent air flow outwardly from the unit through the bleeder orifice, in said nozzle. As movements of the lever FA give rising and falling movements to the pivot pin 1 "K, the pin K of the lever K moves the valve J away from, and permits it to move back toward thenozzle J 4 Q I The movements of the valve J toward and away from the nozzle J increase and diminish the controlling air pressure within the device JA, and hence, in the pressure chamber of the motor pressure valve J which is thereby actuated t variably throttle the flow through a pipe J in accordance with the movements of the pivot pin The link D which has one end connected to the uprising vertically disposed arm of the lever GB of the device JA, has its other end connected to a lever, or equalizing b'ar, QA at a point intermediate the ends of the latter. The lever QA is pivotally connected at its upper end to the free end of an arm DA carried by a normally stationary rock shaft D" which may be angularly adjusted manually, as by means of a screw driver insertedin a kerf in the end of said shaft. The latter is adapted to be held by a friction washer, or otherwise, in any position into which it is adjusted. The manually eflfected angular adjustments of the arm DA, giving angular adjustments to the lever GB-of the device JA. thereby modify the temperature which the control system tends to maintain in the portion of the fur- .nace in which the bulb es is located.

The lever QA and thereby the lever GB and \valve J, of the device JA, are each angularly adjusted to effect a corresponding variation efinterior of the element U is connected by a pipe J to the control pressure chamber of an air controller device JB. The latter may be, and as shown is, identical in construction and form with the device JA. .The device JB has its pressure chamber connected to the compressed air supply piping J by a restricted orifice J. The lever GA of the device JB is connected by a link Eato the arm E? ofsthe Bourdon tubedevice EB. The lever GB of the device JB is connected by a link D directly to the arm DB of a manual adjusting device which'includes an adjustable shaft D and which is shown as exactly like the previously described manual adjusting device including the arm DA.

In the normal operation of the apparatus illustrated, the controller JA is actuated by the control element EA to increase and decrease the fuel supply through the pipeJ", as required to maintain the furnace temperature of the portion of the furnace in which the bulb es is located at a particular value. That value is determined by, and varies with, the adjustment of the lever GB of thecontroller JA. When the temperature to which the'bulb es is responsive. rises above the proper value, the resultant counter-c ockwise movement of the lever GB of the device JA increases the throttling eil'ect of the valve J on the bleeder orifice of the controller 'JA, and thereby increases the pressure transmitted through the pipe J to the valve J, which is thereby adjusted to diminish the flow of fuel to the furnace S through the pipe J Conversely, when the last mentioned temperature falls below the value fixed by the existing adjustment of the lever GB of the device JA, the valve J is adjusted to increase the supply of fuel to the furnace S.

The lever GB of the controller JA is adjusted by the controller JB to increase or decrease the furnace temperature which the controller JA tends to maintain, by a decrease or increase, respectively,- in the exit fluid temperature, to which the bulb et is responsive, above or below the predetermined value thereof. When that temperature rises above its predetermined value, the arm E of the element EB turns counterclockwise and, through the resultant increased throttling effect given to the valve J of the controller JB, the pressure transmitted from the latter through the pipe J- to the bellows element U is increased. The resultant expansion of the latter gives a clockwise adjustment to the lever GB of the controller JA. The last mentioned adjustment increases the throttling effect of the valve J' of the controller JA, and thereby directly causes a reduction in the fuel supply to the furnace through the pipe J In consequence of that adjustment, also, theelement EA will thereafter act to maintain a value of the temperature to which the bulb es responds, which is lower than that previously maintained.

When the temperature to which the bulb et is responsive fallsbelow its predetermined value, the lever E of the element EB turns clockwise and causes a lower pressure to be transmitted to the element U, thereby producing a counterclockwise adjustment of the lever GB of the controller JA. That adjustment diminishes the control pressure maintained by the element JA and thereby directly increases the fuel ,supply to the furnace through the pipe J", and thereafter the element EA operates to maintain the furnace temperature to which the bulb es is responsive, at a higher value than was maintained prior to thatadjustment.

The ultimate result of the control apparatus illustrated, is to maintain the exit fluid temperature to which the bulb et responds, approximately constant and equal to predetermined value which is fixed by the adjustment of the manually adjustable device DA of the control unit JB. Owing to the heat inertia or furnace lag of the furnace S, the regulation provided for in-the apparatus illustrated,-will ordinarily be more satisfactory, and less apt to involve objectionable hunting, than if the apparatus shown were simplified by the elimination of one of thee nerically claim certain generic features of inven- I tion disclosed herein.

While in accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my'mvention now known to me, it will be apparent to those skilled in the art that changes may be made in the forms of the apparatus disclosed without departing from the spirit of my invention as set forth in the appended claims, and that, in some cases, certain features of my invention may be used to advantage without a corresponding use of other features. i

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1. The combination with a work heating furnace, of two air actuated controllers each in-\ cluding adjustable valve means and operating means therefor comprising a horizontally disposed floating lever, suspension means for said lever comprising two elements, one of said elements being a rock lever connected to one end 'of said floating lever and mounted. for oscillatory adjustment about a horizontal axis to thereby raise and lower-said one end of the floating lever and the other element being a vertically disposed ling pivotally connected at its lower end to the second end of said floating lever and adapted for longitudinal adjustment to thereby raise and lower said second end of the floating lever, means for adjusting one of the said elements of one controller in accordance with variations in temend of the floating lever and the other element being a vertically disposed link pivotally connected at its lower end to the second end of said floating lever and adapted for longitudinal adjustment to thereby raise and lower said second end of the floating lever, means for adjusting one of the said elements of one controller in accordance with variations in a temperature condition of the heater, means through which the second element of the last mentioned controller is adjusted by the other controller, means for adjusting one of the elements of said other com troller in accordance with variations in the temperature of the fluid heated in said heater, and

means through which the first mentioned con-' troller regulates the supply of heat to said heater.

3.. Control mechanism comprising in combination, two airactuated controllers each includperature condition of the furnace, means 2. The combination with a fluidheater, of two air actuated controllers each including adjustable valve means and operating mean-s therefor comprising a horizontally disposed floating lever,

suspension means for said lever comprising twoelements, one of said elements being a rock lever connected to one end of said floating lever and mounted for oscillatory adjustment about a horizontal axis to thereby raise and lower said one ing adjustable valve means and operating means therefor comprising a horizontally disposed floating lever, suspension means for said lever comprising two elements, one of said elements being a rock lever connected to one end of said floating lever and mounted for oscillatory adjustment about a horizontal axis to thereby raise and lower saidone end of the floating. lever and the other element being a vertically disposed link pivotally connected at its lower end to the second end of said floating lever and adapted for longitudinal adjustment to thereby raise and lower said second end of the floating lever, means for adjusting one of the said elements of one controller in accordance with the departure of a control quantity from a normal value thereof, means through which the second element of the last mentioned controller is adjusted by the other controller, means for adjusting one of the elements of said other controller in accordance with the departure from the normal value \of a control quantity varying independently of the first mentioned control quantity, means for adjusting the second of thetwo elements of the last men.- tioned controller to vary the normal value of the last mentioned control quantity, and a fluid pressure regulator actuated by the first mentioned controller and regulating the first mentioned control quantity.

" THOMAS R. HARRISON.

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