US2305429A - Thermostatically controlled liquid fuel feeding device - Google Patents

Description

Dec. 15, 1942. R. w. JOHNSON ,4

1 THERMOSTATIGALLY CONTROLLED LIQUID FUEL FEEDING DEVICE Filed Dec. 23, 1939 3' Sheets-Sheet l f a l .55

mvENToR Fay W JU/V/I/JOA/ ATTORNEY Dec. 15, 1942. R. w. JOHNSON Y ,4

' THERMOSTATICALLY CONTROLLED LIQUID FUEL FEEDING DEVICE Filed Dec. 23, 1939 3 Sheets-Sheet 2 D66. 15, 1942. JOHNSON 2,305,429

' THERMOSTAIICALLY CONTROLLED LIQUID FUEL FEEDING DEVICE Filed Dec. 25, 1959 v a Sheets-Sheet .s

I INVENTOR 1P0? M/ Jam 50M BY mum ATTO R N EY Patented Dec. 1942" rnmmosra'rrcstmz comaounn mourn m1. resume nnvrcn Roy W. Johnson, Milwaukee, Wis.

Application December 23, 1939, Serial No. 310,777

2 Claims. (Cl. 236-48) This invention relates generally to a thermostatically controlled liquid fuel feeding device, and more particularly to a device of this character which is especially designed and adapted for controlling the operation of oil-burning water heaters.

One of the objects of the invention is to provide a control mechanism of this character, which insures a dependable oil flow, and the maintenance of a definite clean low fire and a full high fire, the possibility of an indefinite intermediate fire being precluded. Another object of the invention is to provide a control mechanism of this character having these advantages, and which may be readily adjusted manuallyto maintain any desired water temperature over a wide range, for-example over a temperature range of from 110 F. to 160 F.

A further object of the invention is to provide a control mechanism of the character referred to, and having the advantages and capacities mentioned, and which is so constituted as to make it practical to eliminate the costly pressuretight thermo bulb well and replace it with a simplified bulb mounting and shield.

A further object of the invention is to provide a control mechanism operated by a vapor pressure responsive, expansible, collapsible diaphragm or bellows-type power element which will move the controlled device to its oil or low fire position upon a failure inuthe power element.

A still further object of the invention is to provide in a control mechanism operated by a vapor pressure responsive, expansible, collapsible diaphragm or bellows-type power element a spring for compensating for the gradual increasing vapor pressure required to continue the expansion of the diaphragm or bellows after its initial distortion. Furthermore, the spring is arranged to compensate for this required increase in pressure without any substantial variation in the load imposed upon the spring.

In carrying out the present invention the control mechanisrn'is preferably combined with a constant level control device, and the control mechanism itself is so constituted and organized as to effect opening and closing movements of its metering valve with a snap action to insure either a definite clean low fire or a full high fire. Any particular water temperature within the range of the control may be selected merely by manually adjusting or turning a temperature regulating knob which is conveniently mounted on the top of the control, and is, of course, accessible from the exterior thereof.

Other objects and advantages reside in certain novel features of the construction, arrangement, and combination of parts, which will be hereinafter more fully described and particularly pointed out in the appended claims, reference being had to the accompanying drawings forming a part of this specification. and in which:,

Figure 1 is a view in longitudinal central vertical cross section showing a thermostatically controlled-liquid fuel feeding device embodying the present invention, parts being shown in elevation for the sake of illustration.

Figure 2 is a view in horizontal cross section taken on line 2-2 of Figure 1 and looking in the direction of the arrows.

Figure 3 is a plan view taken from line 9-3 of Figure 1 and looking in the direction of the arrows showing the device with cover removed.

Figure 4 is a fragmentary -view in vertical cross section taken on line 4-4 of Figure 1.

Figure 5 is a similar view taken on line 5-4 of Figure 1.

Figure 6 is a view in elevation showing the control proper detached fromthe constant level. de-

vice but equipped with its capillary tube and thermo bulb.

Figure '7 is a view partly in elevation and partly adjusting lever; and

Figure 11 is a fragmentary view in transverse section taken on line llil of Figure 2.

Referring to the drawings. and more particularly to Figure 1, it will be seen that the liquid fuel feeding device embodying the present invention, comprising a casing designated comprehensively at C and including a main casing l2 and a cover or control casing I3, is applied to the top of the main casing i2 and suitably or releasably, interconnected therewith, as for example by a number of screws H. A so-called constant level valve is provided in the main casing l2. and includes a float control inlet valve i5 and a safety cut-oil mechanism designated generally at it. These parts will not be described in detail as perse they form no partof the-present invention and are fully described and claimed in United States Letters Patent 2,068,138, granted to Roy W. Johnson, January 19, 1937, for Device for controlling now of fiuid to oil burners and the like.

The casing is provided with the usual outlet which is connected up to the burner in the usual way and flow through the outlet is regulated by metering valve |1 biased to open posiheld in position thereon by a nut 46. The coltion by a spring and controlled as to position by the control device constituting the present invention.

The details of the valve construction also per se form no part of the present invention but are fully described and claimed in my application for "Interchangeable metering valve control," filed June 23, 1938, Serial No. 216,336.

The control device, in which the present invention is embodied, comprises a valve-operating lever 26, which may be stamped from sheet metal (see Figures 1- and 8). At' one end the lever 26 is provided along its side edges with apertured mounting ears 2|. A pivot pin 22, supported by lugs 22, cast integral with the control casing l2,

' extends through the alined opening of the ears 22 to fulcrum or pivotally support the lever 26 at one end. At the end opposite its fulcrum the lever 26 hasan offset valve engaging arm or portion 24, which is designed to bear against the upper end of the metering valve |1 so that when the lever 26 is swung in such manner that its arm 24 moves downwardly toward the valve l1, it moves the valve H to low or pilot fire position, whereas when the lever 26 is so moved that the arm 24 is swung away from the valve, the spring with which the metering valve is equipped moves the valve to high fire position. This valve-operating lever 26 is also provided with an offset and pointed projection 26 for a purpose which will hereinafter more clearly appear.

A thermostatically controlled actuating lever 26 is combined with the control and is shown in detail in Figure 9. This lever is positioned in the control to underlie the valve-actuatin lever 26. The lever 26 may also be stamped from sheet metal, and adjacent one end is provided with side flanges 21 having transversely alined pivot openings 26 through which the pivot pin 22 also extends, this pivot pin providing a fulcrum for the lever 26 as well as for the lever 26. The flanges 21 of the lever 26 overlap thepivot ears 2| of the lever 26. Washers 29, mounted on the pivot pin 22, are interposed between the flanges 21 and the pivot pin supporting lugs 23.

The body of the lever 26 to one side of its fulcrum is provided with an upwardly displaced portion 36 centrally apertured as at 3| and having bearing seats 32 on its underside on the opposite sides of the aperture or opening 3|. The

opening 3| of the portion 36 of the lever 26 is axially alined with a power element or bellows, designated generally at 36. This power element is releasably, secured against an inwardly directed annular flange 36 integral with the top of the cover and provided at the lower end of a chamber 61 formed in the top of the cover to accommodate the power element. Screws 38 releasably fasten the power element in position. The power element includes a casing 39 and an expansible diaphragm 46 suitably combined and hermetically sea-led to the casing. A short vertical shaft 4| has its upper end suitably attached to the center of the diaphragm 46, and its lower end extends down through the opening 6| in the lever 26. Below the lever 26 a plate-like between and confined by the cups.

lar is oblong in form, and at its ends has upwardly directed pointed projections 44 which engage the bearing seats 62 in the displaced portion 66 of the lever 26. This construction provides a driving connection or motion transmission train between the power element 26 and the actuating lever 26 of such a character that when the volatile fluid. with which the power element is partially charged, cools and the vapor pressure decreases, atmospheric pressure acting upon the diaphragm 46 will cause the shaft 4| to move upwardly, whereby the lever 26 will be swung in a clockwise direction as viewed in Figure 1. When its charge is heated up the vapor pressure increases and overcomes the force of atmosphere acting upon the diaphragm 46 causing the shaft 4| to move downwardly whereby the lever 26 will be rotated in a counterclockwise fashion, as viewed in Figure 1 by the compression in the coil spring 66 hereinafter described.

Intermediate its ends the lever 26 is provided with a longitudinal slot 46, which underlies the projection 26 of the valve-operating lever 26, and also extends to one side thereof. At one end of the slot 9. pointed and offset projection 46 is provided, and is longitudinally alined with the projection 26 of the valve-operating lever. Spring cups 41 and 46 are engaged with the projections 26 and 46, respectively, and have their body portions suitably socketed or seated for this purpose. embrace a compression coil spring 46 interposed One end of the lever 26 is formed with a. second pointed projection 66 which is disposed in cooperative relation to a 'cooperable pointed projection 6|, which is fixedly or adjustably mounted on the control casing. For this purpose the projection 6| may have the portion of its shank threaded, as at 62, and interengaged with the threaded hole in the wall of the-casing that may be secured in adjusted position by means of a nut 62. Spring cups 64 and 66 are engaged with the pro jections 66 and 6|, respectively, and receive and confine the ends of the compression coil compensating spring 66.

The projection 6| is so positioned relative to the pivot pin 22 and the arc of travel of pointed projection 66, that the-line passing between the points 66 and 6| never passes above the axisof pivot pin 22. Thus, spring 66 continually urges lever 26 in a clockwise direction. As the pointed projection 66 moves upwardly upon the counterclockwise motion of the lever 26, the moment of force exerted by the coiled compression spring 56, tending to cause the lever 26 to move in a clockwise rotation, rapidly decreases. This is due to the rapid decrease in the length of its effective lever arm with respect to pivot pin 22. The arc of the travel of pointed projection 66 is very short and as it is about the center of pivot pin 22 positioned a substantial distance therefrom the point of projection 66 moves through substantially a straight line. Hence, there is little compressing or stretching of spring 66, its compensation being accomplished through the change of the moment of force exerted by it as its axis of action rotates about the fixed projection 6|. As the distance betweenprojections 66 and 5| is decreased by the manual adjustment of projection 6|, the greater will be the swing of collar 42 is assembled with the shaft 4| and is 76 the axis of spring 66 for the same angular move- The flanges of the cups 41 and 46 I. is fashioned to provide a spring seat 61 in which one end of a coil spring ll is engaged, and the opposite end of the coil spring Ills interengaged with the spring seat 59 provided on an adjusting lever I. The adlusting lever II has the end thereof opposite its seat II fulcrumed on a pivot pin Ii suitably supported by the control casing. The lever 80 may be moved to vary the compression of coil spring II by virtue of the pro'vision oi an adjusting regulating knob 82 which is'fixed to the upper end of the adjusting screw 3. The adjusting screw 03 has the m installing the control embodying the present invention on a water heater, as for example on an oil-burning water heater of the type shown in Figure 5. a portion of the insulating jacket "'8 is cut away asat. 0 1, and the thermobulb ll is placed against the metal wall I of the heater,

and is held in by means of a cover plate I! releasably fastened to the jacket and covering the opening or. recess 81.

As viewed in Figure 1, the parts are shown in high fire position with the lever urged against its stop I2 by the spring 49. The temperature at which the control will move to low fire position is predetermined by the adjustment of resulating knob 82. The greater the compression of spring II the lower that temperature pointwill be. Asthe temperature of the water in the I tank 2 increases, vapor pressure increases to threaded portion 64 of a shank interengaged with the threaded bearing 0! provided in the top of the control casing. The lower end of the screw Q3 bears down against the lever 80. As

the knob 82 is turned in one direction the screw '3 is fed-downwardly and depresses the lever ill to increase the compression of the coil spring Ii. Reverse turning of the screw '3 decreases compression of the spring 58. The compression in spring 58 acts against the force of atmosphere against the diaphragm l0 and continually urges it to expand. The spring 58 thus continually tends to move the lever arm 26 in a counterclockwise direction, which efiects the movement of the control valve to its low fire position, as hereinbefore explained. Hence, if there is a failure or leakage in the bellows 35, so that atmospheric pressure exists on both sides of the diaphragm ll, the spring Bl, having sufilcient force, will move the control device to the low fire position and hence safe feature. 7

High and low fire stops are provided and coact with the arm 2! of the valve-operating lever 20 to determine the high' and .low' fire position of the metering valve. The low fire stop, which constitute a failis designated at It, may be in the form of an invertedscrew having its shank l1 interthreaded with an adjusting sleeve 68 threadedly interconnected with the top of the control casing. The head 69 of the screw of the low fire stop is at its lower end, and is in the path of the swing of the arm 24 of the valve-operating lever. A nut 10 and spring 1| releasably secure the lowfire stop in any selected adjustment.

-Two high fire stops, designated at 12 and II, are provided. One of these high fire stops,

namely the stop 13, is factory adjusted, and may be secured in place by a drop of solder, or the like, so as to provide a fool-proof maximum adcause a downward movement of the shaft ll. The consequent stretching of the diaphragm I is aided by the force compressed into spring it by the regulating o! knob 2. The downward movement of shaft ll permits lever 20 to move counterclockwise and decreases the moment of force with which spring 58 resists such counterclockwise movement. With each increment of increase in vapor pressure, there will be increasingly large increments of stretch resistance in the diaphragm 0. At the same time the effective aid of coil spring It is slightly decreased,

due to its expansion and consequent loss of someof its potential energy. However, the increasing iorce, required to efiect fu'ither increments of movement of the lever 2G in a counterclockwise direction, is directly compensated for and balanced by the decreasing moment of force of compensating spring 58.

When the predetermined temperature of the water in the tank has been reached the lever 26 will have carried its pointed projection 46 above the line between the point 25 on valve-operating lever 2. (now in its high'fire or upper position) and the pivot 22 andtlie valve-operating lever 20 will be moved clockwise with a snap action to its low fire position. As the bellows 3! expands in the movement to low fire position, and as the bellows 35 is operated under an internal pressure normally lower than atmosphere, it a leak occurs in the bellows, atmospheric pressure is permitted to enter and equalize the pressure on both sides of the diaphragm 40. The force of the spring II will then move the controlfto justment. The fire stop 12 may be adjusted in An adjustable stop has its inner end positioned to engage withthe upper surface of the outer end 0! lever arm 26 to limit the counterclockwise motion thereof.

pressure ,in the bellows 35 decreases. lows starts to gradually collapse due to the effectof atmospheric pressure operating on the outside of diaphragm 40. Such gradual collapse of the bellows unstresses diaphragm ll and it inherently exerts less force in aiding the collapse. The collapse of the bellows 3' also compresses spring 58. The force required to compress spring 58 increases with each increment of collapse of the bellows and compression of that spring. However, the collapse of bellows 36 directly causes a clockwise movement of the lever arm 26. This clockwise movement is aided by the moment of force in compensating spring I. This moment of force increases with each increment of clockwise movement of lever II and hence compensates for the loss of stressed tension in diaphragm 40 and the increased compressive force in spring 58. Hencejboth the force changes, due to the collapsing and expanding of the bellows, and the compression and expansion of spring 58. are variably balanced by the compensating spring 56, and the ultimate movement of the metering valve is controlled accurately and entirely by the change in vapor pressure due to change in degree of temperature. The effect is to make the device operate within a closer range of high and low temperatures.

The net results of this structural organization is that a more sensitive control element is provided, one which operates on a smaller temperature differential,- and one which insures a definite, clean, low fire and a full high fire.

While I have shown and described one construction in which the invention may be advantagecusly embodied, it is to be understood that the construction shown has been selected merely for the purpose of illustration or example, and that various changes in the size, shape, and arrangement of the parts may be made without departing from the spirit ofthe invention or the scope of the subjoined claims.

I claim:

1. In a control device for mechanisms having a high position and a low position, a pivoted actuating lever having limited movement in one direction to cause said mechanism to assume its high position and limited-movement in the opposite direction to causesaid mechanism to assume its low position, a spring acting upon said lever to constantly urge it in the low direction, a vapor pressure responsive, expansible, collapsible power element operatively associated with said lever to positively move said lever in the high direction as said power element collapses, said lever being moved in the low direction by said spring gas said power element expands, said lever having a fulcrum thereon movable through an arc of limited length as said lever moves from low position to high position, a relatively fixed rection, and a compensating compression spring pivotally mounted on said opposed fulcra to continually urge ,said lever in said high direction whereby the relative movement of said fulcra eflects substantial changes in the turning moment exerted upon said lever by said compensating spring.

2. In a control device,, a pivoted actuating lever for limited pivotal movement, an adJustable compression spring acting upon said lever to urge it to move in one direction, a vapor pressure responsive, expansible, collapsible power element acting when collapsed to urge said lever to move in the opposite direction, a compensating spring continually urging said lever in said opposite direction, said spring being pivotally supported by and between a fulcrum point on said lever and a fulcrum point relatively fixed with respect to the pivot point of said lever, the distance between said fulcrum points being short with respect to the distance between said relatively fixed fulcrum point and the pivot of said lever, said fixed fulcrum point being disposed so that a line between it and the pivot of said lever falls outside of the range of movement of said lever but close to the limit of movement thereof in the direction in which it is moved by said compression spring, said relatively fixed fulcrum point being manually adjustable toward and from the fulcrum point on the.lever to vary the distance between said points whereby the variation in turning moment exerted on said lever by said compensating spring may be increased or decreased while maintaining a substantially uniform load on the spring for any position of adjustment of said fixed fulcrum point.

' ROY W. JOHNSON.

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