US2285746A - Construction fok stoves - Google Patents

Description

June 9, 1942. R. c. SABINS 2,285,746

CONSTRUCTION FOR STOVES Original Filed Feb. 15, 1939 KSheets-Sheet l Z] 4/ 5a 53 I 22 J5 30 v i Z8 55 I 12 1/ v I 43 1 fir u I i i 5 F Ii ii I w 7 H I INVENTOR. JZoZZazzdCJabuza, BY

ywww ww w June 9, 1942. R, c, SABINS 2,285,746

CONSTRUCTION FOR STOVES Original Filed Feb. 15, 1939 2 Sheets-Sheet 2 Patented June 9, 1942 CONSTRUCTION FOR STOVES Rolland C. Sabins, Wisconsin Rapids, Wis.

Original application February 15, 1939, Serial No. 256,448. Divided and this application April 1,

1940, Serial No. 327,163

4 Claims.

This invention relates to a new and improved draft control construction for stoves and more particularly to the location and design of a con trol damper and of the walls and passage adjacent the damper. While my invention is especially adapted for use in connection with space heating stoves of the oil fired type, it may be used in connection with other types of stoves or furnaces.

My invention is directed to the type of draft control which includes a pivoted damper located in the wall of a passage or chamber connecting the stove and stack and carrying oil the products of combustion. In oil fired stoves the amount of fuel burned, and consequently the heat generated, is controlled by means of a valve which regulates the flow of fuel to the burner. Such burners have heretofore been equipped with a draft control damper located in the wall of the flue or stack and in some cases these dampers are provided with manually adjustable means for varying the draft. With heaters of this character a single adjustment of the damper is not effective since the draft requirements change with different positions of the fuel regulating valve. With greater fuel flow and greater generation of heat, a greater draft is required in order to maintain proper .combustion and to carry off the increased volume of the products of combustion than is required with smaller fuel flow and a low flame. The proper draft for a high flame is too great for efiicient combustion with the smaller flame.

This application is a division of my copending application Serial No. 256,448, filed February 15, 1939.

It is an object of the present invention to provide a new and improved draft control construction.

It is an additional object to provide apparatu of this character which is automatic in operation to provide the draft required by the combustion in the heater or stove.

It is a further object to provide apparatus of this character comprising a damper shielded from the direct flow of gases and capable of efiective draft control by relatively small movements.

It is an additional object to provide apparatus comprising a balanced damper with a manually adjustable weight provided with additional automatic thermostatic adjustment.

It is also an object to provide a draft control construction in which the outgoing products of combustion from the stove are deflected downwardly below the variable draft intake opening.

It is a further object to provide apparatus which may be located directly at the stove or heater and attached thereto.

Other and further objects will appear as the description proceeds.

I have shown certain preferred embodiments of my invention in the accompanying drawings, in which-- Figure 1 is a vertical elevation of a liquid fuel stove with my improved draft control applied thereto;

Figure 2 is a fragmentary vertical section through the draft control on an enlarged scale;

Figure 3 is a View of the construction of Figure 2 as seen from the right; and

Figure 4 is a fragmentary section taken on line i4 of Figure 2.

Referring first to Fig-ure 1, the stove construction comprises an outer housing II and a combustion chamber or drum I2 in which is located the firepot I3. The liquid fuel is contained in a tank I4 from which the liquid passes through pipe l5 to the adjustable control valve Iii. The pipe I! connects the valve I6 and the pot burner I3. Details of the stove construction itself form no part of the present invention and need not be further described herein.

The products of combustion rising from the pot burner I3 through the combustion chamber or drum I2 pass from the chamber I2 through the opening I8 formed in the rear wall of the combustion chamber. The rear wall of the combustion chamber is provided with the collar GI secured thereto by welding or by other suitable means. The draft housing I 9 fits over the collar M and may be secured against accidental displacement by the screws 42 threaded into the metal. The discharge passage 26 leads from the lower portion of the control chamber I9 from the side opposite to the opening I8. It will be noted, however, that the passage 29 is not in alignment with the opening I 8 but is offset in the downward direction a distance equal to approximately one-half the diameter of the opening. The damper supporting member H is fitted into the control housing above the discharge passage 20. The lower edge of the damper extends to a point closely adjacent the discharge opening 2i), being located above that opening.

The deflecting wall 22 is located in the control housing and extends in front of the damper 23. It will be noted that the deflecting wall 22 extends down opposite approximately the upper half of the discharge opening I8.

The damper construction is shown in detail in Figures 2, 3 and 4. The supporting member 2| is preferably circular in shape and provides a circular opening for the damper 23. The damper 23 is supported upon a transverse pivoted member 24, the ends of which are secured to the member 2|. This pivot is located preferably somewhat above the center of the damper, so that the normal tendency of the weight of the damper itself is to maintain the damper in vertical position closing the opening. The lower edges of the damper is provided with a stop lug 25 adapted to engage the member 2| to prevent the lower edge of the damper from swinging outwardly beyond the vertical.

The bi-metallic strip 26 is securedto the outer face of the damper by means of'rivet 21', and the upper end of the strip has a; threaded: opening.

receiving the threaded rod 30. This rod:39jcar;- ries the lock nut 28 provided with the enlarged portion 29 by means of which it may be manually rotated to lock the rod 30 in adjusted position in the strip 26. upon its inner end with the weight 3!. The outer end of the rod 30 carries the adjusting knob 32 by means of which the rod may be rotated to screw it inwardly. or outwardly, thus ad.- justing the effective lever arm of the weight3l. A fixed Weight 33 is secured to the damper. adjacent its upper edgeby means of the screw 3.4.

The adjustment of'the automatic control will.

depend somewhat upon local conditions, as. the natural draft will vary with the barometrictpres sure and. consequently with the altitude of." the point where the stove isused. Itwill also vary with the character andlength of the piping and chimney connected to the stove. It will. be understood that with the pot type of. fluid burner, such; as shown in the drawings, the valve IE. will have a number of predetermined. adjustments which control the amount of oil flowing into the burner and consequently the amount of oil burned in a given. time. The weight 3! is adjusted relative to the damper by. turning the knob; 32. until; with a given valve setting the damper, is adjusted to give the desired draft in the stove. will automatically take care of the draft when different adjustments. are made of the control valve l6.

Thisbi-metallic strip 25-is of such acharacter that. whenthestrip-becomes heated-it tends to curve to the left, as shown in Figure 2, andmove in toward the face of the'damper 23. This-movement carries the-weight 3|"to the left and increases its lever arm in acting upon the damper- 23. This increase in-leverage causes the damper to swing toward the closedposition. With the damper closed-or more-nearly closed; the amount of air coming in through the opening is decreased and consequently the effective draft upon the stove itself is increased. This effective draft is necessary to take care. of "the increased combustion in the stove.

The, device operates in the opposite directionwhen the valve lfi'is adjusted to cut down the flow of oil to the burner, and consequently to cut down the flame. As the strip 23 cools it swings to the right, movingthe weight 3| to the: right and tending to swing .the damper 23-inthedirection to open the damper. and permit a greater influx of air at this point. This cuts downthe effective draft upon the stove and the lower flame in the stove burns properly. Thus the bimetallic member serves toincrease or reduce-the draft This rod 30. is provided Thereafter the bi-metallic strip 28;

in proportion to the. heatappliedthereto, which heat is in proportion to the draft demands of the stove.

The secondary or counter-adjusting Weight 33 serves a dual purpose in combination with the automatically variable adjustable weight 3|. The primary purpose of this weight 33 is to balance the damper vane when the weight 3| is in a position toward the right, as seenin Figure 2. s the heat in the stove. increases and the bimetallic strip 26 moves to the left swinging the weight 3| to the left and increasing its leverage upon the damper 23, the fixed weight 33, since it is in.a.fixed;p.osition, tends to shorten the travel of the weight 3|.necessary to accomplish the desired adjustment: The weight 33 is applied on the inside of the. damper vane 23 and above the pivot; Itseffectin. swinging the vane increases as the vane leaves the vertical position. This flxedweight has the reverse effect when the automatically movable weight moves in the opposite, direction. and. again aidsincausingthe effective movement of. the: damper t0.take place Witha minimum.travelzofitheweight3 The bafile or deflecting walll22'isimportant in thatit preventsfl'ue; gases and smoke from risingup and-sweeping;acrossthe'face of. the draft vane-or. damper. 23; Such. .gases or smokewould tendto: deposit carbon andichang the draftadjustment. The wall 22 also serves to direct the flue gases downwardly toward the passage. 20 and causes themto. movepast the;1ower. edge of therdamper openingzratherthan across the face of theopening. The Wall 22:. also has arfurther practicakeffect of. preventing light from the combustion chamber being reflected through the damperopening upon the wall back of the stove, which'is usually considered undesirable.

Withth'e; movable damper. vane. located in the manner shown; a. considerable byi-pass ofroom atmosphere into-theflue 25 is accomplished by. a very. small movementof; the-damper, which affordsvery close draft regulation.. The air passes directly. under: and past:the. lower edge. of the damper into theflow of? gases'through the passage 20. With dampers located in theconventional mannerparalleljtothe passage, a considerablemovement-of the damper is requiredito afford'any substantial openingfor. the flow of air inwardlypast the damper... A further advantage of the present location of parts, including that of the damper and of the deflecting: Wal122, is that theheated products. of combustion coming out from the-stove must pass down. to alevel below the center-of the stoveoutlet opening l8. This downward flow of the gases at this point causes some resistance to-thegaspflow, and gives a iavorable-pressure difi'erentialto the flow of air through the damper controlled opening. This againaids in affording very close draft: regulation,= a-s any. sudden increase in draft is applied more directly't'o the .draft'vane than to the gases coming through the flue opening. ifthe damper opening and'draft. opening l8. wereinline with eachother. anyysuddemchange in draft would be applied more: directly. to the firebox than to the damper. Consequently the construction minimizes: sudden; fluctuations and affords a more stable-and efficient control of draft.

The use-of" the. improveddamper control has been discussed in connection withan oil burning stove for space. heating. With such astove the control of the-'amountofzflame is afforded by; the valve. which: limits the flow of fuel to the heater: burner. Consequently the draft-control-is awsecondary control and; it is desired to have it operate in accordance with the temperature in the heater to increase draft with increased temperature or with increased combustion so as to supply adequate draft for the combustion.

The damper and control construction may be applied to other types of stoves or heaters burning other fuel, such as coal or wood. In the case of such stoves there is no control of combustion by controlling the admission of fuel to the stove. Consequently in such cases the damper must act as the primary control. This means that the damper will ordinarily have the reverse adjustment from that just described in connection with the oil burning pot burner type of stove. In other words, it will be desirable with coal or wood stoves to reduce the draft as the heat grows great so as to prevent excessive heat and prevent the fuel from burning up too rapidly. On the other hand, when the fire gets low it may be desirable to have the draft automatically increase so as to keep up the proper combustion. Therefore, in some applications it may be desirable to reverse the damper control construction and have the bi-metallic strip 26 turned in the opposite direction so as to increase draft as it gets cold, rather than when it gets hot. It will be noted that the bi-metallic strip is located externally of the control chamber. This makes the strip in part responsive to surrounding atmosphere, but more particularly it has the efi'ect of making the strip less responsive to sudden fluctuations in temperature. It also prevents corrosion of the strip due to contact with flue gases.

While I have shown certain preferred embodiments of my invention, these are to be understood to be illustrative only as the apparatus may be varied to meet differing conditions and requirements and I contemplate such modifications as come within the spirit and scope of the appended claims.

I claim:

1. In a stove construction, a combustion chamber, a wall of the chamber having an opening therein for the discharge of products of combustion, a control chamber communicating with the combustion chamber through the opening, a discharge passage leading from the wall of the control chamber opposite to the opening and offset downwardly relative to the opening, and a damper-controlled opening in the control chamber wall opposite to the opening to the combustion chamber and offset vertically above said combustion chamber opening.

2. In a stove construction, a combustion chamber, a wall of the chamber having an opening therein for the discharge of products of combustion, a control chamber communicating with the combustion chamber through the opening, a discharge passage leading from the wall of the control chamber opposite to the opening and offset downwardly relative to the opening, a damper-controlled opening in the control chamber wall opposite to the opening to the combustion chamber and offset vertically above said combustion chamber opening, and a deflecting wall in the control chamber between the combustion chamber opening and the damper-controlled opening, said deflecting wall being spaced from both said openings.

3. In a stove construction, a combustion chamber, a wall of the chamber having an opening therein for the discharge of products of combustion, a control chamber communicating with the combustion chamber through the opening, a discharge passage leading from the wall of the control chamber opposite to the opening and offset relative to the opening, and a damper-controlled opening in the control chamber wall opposite to the opening to the combustion chamber and offset relatively thereto, the damper being a pivotally supported swinging damper, the discharge passage and damper opening being closely adjacent each other and each being opposite a substantial portion of the combustion chamber opening.

4. In a stove construction, a combustion chamber, a wall of the chamber having an opening therein for the discharge of products of combustion, a control chamber communicating with the combustion chamber through the opening, a discharge passage leading from the opposite side of the control chamber and offset relative to the opening, a damper-controlled opening in the control chamber wall opposite to the opening to the combustion chamber and offset relative thereto, the damper being a pivotally supported swinging damper, the discharge passage and damper opening being closely adjacent each other and each being opposite a substantial portion of the combustion chamber opening, and a deflecting Wall in the control chamber between the damper controlled opening and that part of the combustion chamber opening opposite the damper opening.

ROLLAND C. SABINS.

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