US1345652A - Furnace construction - Google Patents

Description

1. F. TUTEIN, v FURNACE CONSTRUCTION. APPLICATION FILED NOV- 29 I919.

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HWIWIIEINI'II'WIN J, F. TUTEIN.

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APPLICATIONFILED NOV- 29,1919

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,naaacaa fipecification of Letters Patent.

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application filed November 539, ram. aerial No. tall/M7.

' for example, as are used to heat water and lid llli till a 5 application. fill generate steam in boilers; and consists in an automatic control of fuel supply. Though not in its broader aspects so limited, my invention finds application in a natural-draft furnace, and in the accom panying drawings it is illustrated in such lfigures l and H are viewsjin side elevation, and at right angles, one to the other, of a furnace structure having the automatic fuel control of my invention applied to it; Fig. llll is a view showing diagramma'tically an additional-detail, which may or may not be employed.

in furnace o oration, maximum efficiency is attaine' when comhu tion is free and when the hurnin gases in necessary volume pass over the heat-conducting sur faces (hoilerrtuhes or other surfaces) at a minimum rate of flow. But there are variable circumstances that have to be de alt with: quality of fuel for example, and condition of fuel, and atmospheric conditions.

lln a general way, such variations in circumstances may he reckoned with in advance. llt is common practice to provide mechanical fuel-feed devices, and to place dampers either in.the air-supply dues or in the chimney passages or in both, and,

while keeping the rate of fuel feed con stant, to vary the damper setting: as conditions grow. less favorable to combustion,

draft is increased; as the grow more favorahle, it is decreased. Tie end in view is, of course, a maximum degree of efficiency. The highest possible efficiency cannot, however, he attained under varying conditions of burning, unless the rate of'nfuel feed he correspondingly varied. I

ft is common, also, in operating steam boilers, to provide automatic means for con-.-

trolling the position of the dampers as steam pressure varies, to the end that, the rate of fuel feed beingconstant, draft conditions shall always be such as to. afford maximum heating effect. Such an arrangement, good and effective so far as it goes, possesses still this disadvantage the rate of fuel feed may cannot always hesuch as to attain maximum heatlng effects.

This disadvantage is recognized, and in recognition of it the expedient is resorted to,

of superadding to the mechanical fuel-feed apparatus a speed-changing device. This specd-changing device is under the manual control'of the operator; he, observing conditions of combustion, may vary the rate of fuel feed, to attain always (within the limits of his wisdom) .best conditions of comhustion.

My invention is predicated on perception of these facts: that pressure in the furnace chamber is the dominant factor in the prolonot loe--indeed, under varying conditions,

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lemj that, does and chimney passage continuing unchanged in size, maximum efficiency is realized when pressure in furnace chamber is of acertain value; and that, under varying conditions of chimney passage, the furnace ressure affordin maximum efiiciency varies accordingly-for each damper setting there is a corresponding furnace chamber pressure, afl'ording maximum efficiency. from these facts ll proceed to my invention, which consists, first, in

- subjecting the speed of fuel feed to the automatic control of furnace pressure to the end that, as furnace pressure tends to vary, the speed of fuel-feed will vary to adord correction; and, second, in bringing'damper setting into the equation just stated, to the end that while as before fuel speed is automatically dominated by furnace pressure (maintaining always the desired pressure ofmaximum efficiency), at the sametime, that furnacepressure of maximum efficiency shall automatically, under varying damper settings, assume a correspondin ly varying actual yalue. lln otherwords: ch remainlng constant, depth of fuel will remain constant, but speed of fuel feed will vary, under changing conditions of combustion, to afford always that pressure in the furnace chamber which affords maximum emciency; and again, damper setting vary setting is most eihcacious.

pressure which under the existing damper are I lldd imney size Ildli hen here and elsewhere, in specification stant pressure in furnace chamber, it will be understood that .I recognize, and do not exclude from m meaning, those minor and transient variations which are incident to essential indeed, to effect-the operation of my automatic feed control; again, when I' say the thickness of fuel is constant, I mean still to include such minor irregularities as are incident to practical conditions, as well as those incidentally encountered, as the automatic machinery makes its adjustments; and so throughout. 7

My invention may be applied either to a furnace of forced draft or to one of natural draft; it is to the latter that I have actually applied it, and I shall describe it in such application. .Its application to a forced-draft furnace will, from what I amabout to say, be sufliciently plain to engineers. I shall first describe the invention in so far as it applies to a furnace of fixed chimney size, and in the sequel describe the further features of invention which concern furnaces having chimneys ings, 1 is the wall of the furnace.

- slideway 9 nearer to and farther from the of variable effective openings-that is to say, damper-controlled chimneys.

Referring to Figs. I and II of the drawa The feed of fuel in this case is effected by chain grate 2, and it is the driving of this chain grate 2 in well known manner which constitutes the mechanical fuel feed of this furnace. The driving shaft 3 of the chain grate 2 is turned ,by the worm drive 4, and this worm drive is in turn driven from a power shaft (not shown). This'unseen power shaft, by means of an eccentric, imparts oscillation to a rod 5. The rod 5, connected to a pivoted arm 6, turns the worm drive 4, by means of the pawl-and-ratchet connection 7 and 8. All of this is familiar construction, and needs no further minute description. Examination of the drawings, in the light of what has just been said, will make the whole perfectly evident to anyone familiar with the subject. The connection between the rod 5'and the arm 6 is an adjustable one, movable in a center of turning of the arm 6. In this way the throw of the pawl and ratchet may bev increased and decreased, and so the speed of turning of the grate may be made to vary.

As has above been indicated, this connection between rod '5 and arm 6 has heretofore been manually adjustable, to the end that the operator, observing furnace conditions, may vary the speedof' the grate...

' My invention, as I-have indicated, consists in automatically controlling that adjustment, according to pressure conditions within the furnace chamber. An oil-sealed bell 10 is provided, of familiar form, the construction of whicl will be suflicientl understood by examining Fig. 2 of the rawings. I The bell chamber is brought into vthis pinion 16 is a disk 17.

that of the furnace chamber will (if it be a natural-draft'furnace) be less than atmospheric. The counterweight 12 tends to raise the bell, the excess of air pressure above, over the furnace-chamber pressure beneath, tends to depress it consequentl the bell stands in equilibrium, and respon s in movement to every change in pressure in the furnace chamber; 'Such movement of the bell is imparted conveniently through the in- Strum'entalities shown to a valve 13, which controls the admission of fluid pressure into a fluid pressure cylinder 14. To the stem of a piston within this fluid pressure cylinder is connected a rack 15, and this rack engages a pinion 16 conveniently mounted idly upon. the same shaft which carries the worm of the worm gear 4. Integral with (The disk shape is unimportant; it serves merely as a connecting lever.) To the disk is pivoted a rod 18, which rod 18 connects the disk 17 to the end of the rod 5. According as this disk 17-turns, the point of connection between rod 5 and arm 6 will vary, and it will be apparent that, according as pressure in the furnace chamber varies, so the position of the connection between rod 5 and arm 6 willvary, the effective length of arm 6 will vary, and so the speed of turning of the chain grate will vary.

' Such being the structure, it will be at once apparent that variations in furnace-chamber pressure expressthemselves in changes in rate of fuel feed, and these changes of fuel feed correct the pressure variations, bringing it back to normal.

I come now to the next feature of my invention; that, namely, which adapts the subject-matter already explained to a furnace which has a dampencontrolled chimney-or damper-controlled air supply. I show and shall describe a damper-controlled chimney; the wider application indicated will readily be understood.

Referring to Fig. III of the drawings, a damper 20 is diagrammatically shown in a chimney flue, which it will be understood is a flue leading from the furnace. Conveniently located with respect to such flue, and

also with respect to the furnace chamber,

for the ends already described, is a bell,

such as that shown at 10 in Figs. I and II.

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tea-aces 20 turns, rests to a greater or less extent within a cup 22 borne on the beam of the eounterweighted bell 10, and adds a greater or less portion of its weight, to augment the effect of Weight 12 upon bell 10. The chain 21 will be selected, to the end that, its weight per linear unit may suit conditions. This showing is diagrammatic merely, to indicate one particular means, whereby the force ex erted upon bell 10 in opposition to furnacechamber pressure to hold the bell in equilibrium, may vary as damper position varies. For every damper position there is an ideal furnace chamber pressure, automatically brought about by the actual weight of so 'much of chain 21 as rests in cup 22 and the proportioning of theparts; and, that ideal pressure being so brought about, speed of fuel feed automatically accommodates itself, to maintain that pressure. The position of the damper may be manually determined. or it may, by known instrumental ities, be caused to vary automatically to meet related conditions: for example, it may be controlled by pressure in a steam boiler heated by the furnace. But, however controlled, the damper will be effective in its movement to accomplish the operation'of the parts described. According as the demand upon the furnace is great or small-- that is to say, for great quantities of heat or lessthe damper opening will be increased or diminished. (This may be manual or automatic.) But, by the operation of my automatic apparatus now described, the rate of fuel feed will be automatically increased till lib

or diminished. Always the most efficient depth of fuel will be maintained, and that depth, whatever the condition is, for the given furnace, substantially constant.

Tt will be seen that, whether the furnace be one of fixed or of variable chimney opening, whether the damper of the variable chimney opening be manually or automatically controlled, my invention still is applicable, and consists in the automatic control of the rate of fuel supply, to suit the ideal pressure (whatever its actual value may be) maintained in the furnace chamber.

To summarise, in the operation of the fur nace to which my invention is applied,.

thickness of fuel is maintained substantially constant, and of predetermined value, under varying conditions of burningand that is as much-as to say, under varying rates of combustion; the ideal pressure in the fur-.

- nace chamber is maintained under varying when that ideal pressure itself varies to lid All:

conditions of burning, and this is true, even meet changed circumstances elsewhere; furnace-chamber pressure varies where effective flue area varies, and varies proportionately, so that always it may stand at-ideal maximum, and at the same time (as has been said) variations in conditions of burn" -particular form of the pressure op ing are elsewhere compensated for, and the ideal pressure is not widely nor perma. nently disturbed, butremains substantially defining the forces to'which the oil-sealed bell 10 is subject, characterized one of them as an independently determined force, and by thisphrase T mean to define a force whose ;value is not determined by fluctuation in gaseous pressure either in the fun nace chamber 'or anywhere in the line of draft of the furnace. Tn the case shown this independently determined force is the effective value of the chain weight 21, and this value is determined by the position of damper 20. The determinatidn then of the value of the force is quite independent of pressure in line of draft.

T claim as my invention: 7

1. Tu a furnace structure the combination, with a furnace chamber, a mechanical fuel feed, and a speed-changing device applied to said fuel feed, of an automatic control for said speed-changing} device including a movable element subject in opposite directions to furnace-chamber pressure and to atmospheric pressure, substantially as described.

2. Tn a furnace structure the combination, with a furnace chamber, a mechanical fuel feed, and a speed-changing device applied to said fuel feed, of an automatic control for said speed-changing device including a movable element maintained in equilibrium between atmospheric pressure and the sum of two forces: one, furnace-chamber pres sure, and the other, an independently deter mined force, substantially as described.

3. Tn a furnace structure the combination, with a furnace chamber having draft passageways, amechanical fuel feed, and a speed-changing device applied to said fuel feed, of an automatic control for said speedchanging device including a movable element maintained in equilibrium betweenatmospheric pressure and the sum of two forces: one, furnace-chamber pressure, and the other, a force constant while said draft passageways remain constant, substantially as described.

4: Tu a furnace structure the combination, with a' furnace chamber, a mechanical fuel, feed, and a speed-changing device ap plied to said fuel feed, of an automatic control for said speed-changing device includ- Till Tllb

Tfltl Add ing a movable element maintained in equilibrium between atmospherlc pressure and the sum of two forces: one, furnace-chamber pressure, and the other, gravity, substantially as described.

5. In a furnace structure the combination, with a furnace chamber, a mechanical fuel feed, and a speed-changing device applied to said fuel feed, of an automatic control for said speed-changing device including a 'movable element maintained in equilibrium between atmospheric pressure and the sum of two forces: one, furnace-chamber pressure, and the other, a force of a value under the control of the operator, substana "tially as described.

\ 6. In a furnace structure, the combination, with a furnace chamber having draft passageways and a damper, a mechanical fuel feed, and a speed-changing device applied to saidfuel feed, of an automatic control for said speed-changing device including a movable element maintained in equilibrium between atmospheric pressure and fuel feed, of a counter-weighted oil-sealed bell communicating with said furnace cham-- ber, a speed-changing device applied "to said fuel feed, and means operated b said bell for controlling said speed-changing device, substantially as described.

8. In a furnace structure the combination, with a furnace chamber and a mechanical fuel feed, of an oil-sealed bell, an adjustable counterweight for said bell, pneumatic connection from said furnace chamber to said bell, a speed-changing device applied to said fuel feed, and means operated b said bell for controlling said speed-changing device, substantially as described.

9. In a furnace structure the combination, with a furnace chamber, a mechanical fuel feed, and a damper controlling draft through said furnace chamber, of an oilsealed bell, a counterweight for said bell, pneumatic connection from said furnace chamber to said bell, a speed-changing device applied to said fuel feed, means operated by said bell controlling said speedchanging device, and means for automati cally effecting variation in the value of said counterweight, according to variation in the position 0 said damper, substantially as described.

In testimony whereof I have hereunto set my hand.

' JOSEPH F. TUTEIN.

V Witnesses:

' EL' ER' E. Born,

H. H. SHAKELY.

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