US2262254A - Stove construction - Google Patents

Description

Nov. 11, 1941. R. c. SABINS STOVE CONSTRUCTION Filed April 6, 1940 4 Sheets-Sheet l 7 JNVENTOIR. 1202mm 6 fiabuw.

Nov. 11, 1941. R. c. SABI NS 2,262,254

I STOVE CONSTRUCTION Filed April 6, 1940 4 Sheets-Sheet 2 INVENTOR.

labile/4d C. alxrze M11, 1941 R. c. SABINS 2,262,254

STOVE CONSTRUCTION Filed April 6, 1 940 4 Sheets-Sheet 3 fiollarzd C 5abuz5,

n- A i INVENTOR.

4 Sheets-Sheet 4 i l 1 a BY 1 l R C SABINS STOVE CONSTRUCTION Filed April 6, 1946 Nov. 11. 1941.

Patented Nov. 11, 1941 UNITED STATES PATENT OFFICE STOVE CONSTRUCTION Rolland C. Sabins, Wisconsin Rapids, Wis.

Application April 6, 1940, Serial No. 328,300

4- Claims.

This invention relates to a new and improved stove construction and more particularly to a new and improved draft regulator and control for stoves.

While the improved regulator and controlis adapted for general use in connection with stoves of different types, it is especially adapted for use in connection with space heating stoves employing pot type burners.

Space heating requires a stove which may be adjusted to low or moderate heats as well as to high heats and which will operate efliciently over a considerable range of heat adjustment. With pot type burners the heat adjustment is made solely by controlling the flow of fuel to the burner. It is found in practice, however, that agiven burner requires much less draft for efilcient operation at a low fuel setting than it does for a high fuel setting. While dampers adapted to cut the effective draft on the burner by admitting room air to the stack or flue, may operate efficiently with regard to combusition they reduce the overall heating efficiency of the stove or heater. This is for the reason that the air admitted to the flue through the damper is heated room air which must be replaced by cooler air drawn into the room by the draft. The use of such dampers for continuous draft control is therefore undesirable. Dampers of this type are suitable for intermittent operation to take care of temporary variations in draft conditions.

Dampers which operate to partially obstruct the flue opening serve to reduce the effective draft at the burner without admitting room air to the flue. This type of damper requires initial adjustment to take care of normal stack draft and requires adjustment with variations in the draft. For example, tests show that with a given stack or ofitake flue arrangement the effective draft may be substantially doubled with a drop of twenty degrees in outside temperature. Provision should be made therefore to permit draft adjustment to maintain substantially the same effective draft at the heater regardless of changes in barometric and temperature conditions.

In addition, the draft must be varied with the input of fuel to the pot type burner, if the burner is to operate efliciently at different settings. The draft required varies with the heat output of the burner and consequently the draft adjustment for different fuel settings can be thermostatically controlled.

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

It is a further object to provide a draft control which may be adjustable to compensate for variations in external draft conditions and is automatically adjustable to take care of variations in draft requirements within the stove or heater.

- trol housing 2!.

It is an additional object to provide a damper control which is thermally adjustable and which is adapted for coaction with a control responsive to relative pressures in the dues and areas adjacent thereto.

It is a further object to provide controls of this character which serve to vary the effective area of the flue leading from the stove or heater.

It is also an object to provide a draft control which is simple in design, composed of but few parts and adapted for commercial production and use.

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 side elevation with parts broken away, showing a stove with the invention incorporated therein; v

Figure 2 is a fragmentary view on an enlarged scale showing the damper construction of Figure 1;

Figure 3 is a view 'of Figure 2 as seen from the Figure 4 is a view similar to Figure 2 but showing a modified form of damper construction;

Figure 5 is a rear face view of the damper construction of Figure 4 Figure 6 is a cross-section of a modified form of damper construction;

I Figure 7 is a section taken on line of Figure 6; .and 1 Figure 8 is a section taken on line 8-8 of Figure 6.

Referring first to the form of construction shown in Figures 1, 2 and 3, in Figure 1 is shown a space heating stove comprising a housing ll enclosing a heating drum l2. The pot type burner I3 is supported from partition il in the drum l2, air for combustionentering through the opening IS in the base .l6 of the drum. Fuel is contained in tankv l1 and is supplied to the burner l3 through the constant level valve I8 and pipe IS. The drum I2 is provided with the open ing 20 for the discharge of products of combustion, this opening discharging into the draft con- The housing 2| is provided with the smoke pipe connection 22 for connection to a flue or chimney for discharge of the products of combustion.

As best shown in Figure 2, the upper portion of the rear wall of the draft control housing 2! carries the .draft control vane 23, supported on a transverse pivot at 24. This pivoted vane type of control is disclosed in my copending application Serial No. 256,448, filed February 15, 1939. The vane 23 has a bi-metallic strip 25 secured thereto, the strip adjustably supporting the weight 26, which may be moved toward or away turned end 53.

cured to the end 53 of the control rod 50 and from the vane by rotation of the knob 21. The fixed deflecting plate 28 serves to keep the direct flow of products of combustion away from the vane 23 and also causes the vane to be less responsive to slight momentary draft fluctuations.

The manual control rod 38 is provided with knob 3| and slides in aligned openings in the wall of the housing II and of the drum l2. This rod 30 carries the downtumed lug 32 to which is secured the bi-metallic strip 33 having the damper support 34 fastened to its lower end. The vane support 34 carries the disc damper 35 which, as shown in Figure 3, is centered in the opening 20in the drum l2. The size of the damper 35 is preferably so related to the size of the opening 28 that the damper covers appro matelv eighty percent of the flue opening when the damper is in its fully closedposition.

The form of construction shown in Figures 4 and 5 differs from that of Figures 1 to 3 in the construction and support of the adjustable vane for the flue opening. The manual control rod is provided with knob 5| and with the downturned inner portion 52 having the out- The damper frame 54 .is secarries the supports 55 for the thermostatic strips 56. The opposite ends of the strips 56 have the connecting members 51 fastened thereto, these connecting members having pins 58 fitting in openings in the damper supports 59 which carry the damper 50. The combined areas of the openings between damper frame 54 and the drum l2 and between the damper 60 and the damper frame, with the parts in the closed position, are preferably approximately twenty percent of the full area of the outlet flue openin The form of construction shown in Figures 6 to 8, inclusive, differs from those of Figures 1 to 5 in that the damper and control construction is located in connection with the flue or smoke pipe rather than directly associated with the heating drum and draft control housing. The

pipe section has the lateral opening 66 formed damper frame I8 also carries the stops 85 adapted to engage the face of the damper 84 and limit its movement in one direction.

The form of construction shown in Figures 1 to 3 includes both a swinging barometric control damper-and a damper located in such position as to vary the effective area of the oflftake flue leading from the combustion chamber or heating drum. The manual control rod 3fl serves to move the damper 35 away fromand toward the discharge opening. This damper as is of such area that the damper and its support when in the position to afford the maximum obstruction to products of combustion still leaves available twenty percent of the cross-sectional area of a standard flue pipe. percent flue area is required by the underwriters laboratories in their limitations as to the use of a damper device of a character tending to obstruct the flue pipe.

. The manual adjustment of the rod 30 will depend upon the effective draft afforded by the flue and stack. For example, if with the rod 38 at its innermost position, leaving the flue opening entirely unobstructed, a draft gauge placed in an opening in the combustion chamber wall or door indicates a draft reading of .15 inch and a firebox draft of .08'inch is desired, the operator would move the control rod 30 outwardly to restrict the outlet for the products of combustion to such an extent that the firebox draft as indicated on the draft gauge reached the desired reading of .08 inch. During this procedure of adjustment the barometric draft control 23 is held in the closed position.

After th proper adjustment for the damper 35 has been found, the barometric draft control is released and the weight 26 is adjusted so that the vane 23 teeters in a closed position. With.

this barometric draft control vane 23 so adjusted, it will react to momentary draft increases and yet will not continuously draw heated room air out through the stack. At the same time, by

the vane housing 68 below and behind the barometric vane 59. The housing 68 contains the limiting stops 18 and 1| for limiting movement of the vane 69 in opposite directions. The vane 59 is positively connected to the rotatable cross shaft 12 which shaft, as shown in Figure 6, carries the counterweight 13 adapted to counterdamper body being supported'by the short shaft- 19. The outer end of the shaft section 19 carries the grooved arcuate member 88 to which is secured one end of the chain 8|. This chain lies in the groove in member 80 and has the adjustable draft control weight 82 fastened to its free end. The-member 80 and the chain support for 'the weight 82 afford that weightia constant lever arm regardless of the rotary position of the shaft 19 and the damper frame I8.

The damper frame 18 has one end of the bi-metallic strip 83 secured .to it, the other end of the strip supporting the damper 84. The

momentary operation as required by draft fluctuations, the firebox draft will be held substantially constant. The adjustment procedure outlined above will be carried out with the metering valve of the heater adjusted at its maximum open position, with the burner therefor burning at its high fire setting. The high temperature of the products of combustion will raise the temperature of the bi-metallic strip to 33 so as to swing'the damper 35 to the left, as seen in Figure 1, thus swinging it awayfrom the outlet opening and increasing the effective area of that opening.

When it is desired to burn the heater at a lower flre setting, the fuel valve is adjusted as desired. With a lower flame the heat of the products of combustion is reduced and' when they reach th bi-metallic strip 33 they have less effect upon that strip. This causes the strip to reduce its curvature, which serves to swing the damper 35 toward th flue opening. The damper being closer to the opening automatically reduces the firebox draft. At the same time 'the reduced temperature also affects the bi-metallic strip 25 on the barometric draft control vane 23 and moves the weight adjustment in the outward direction in proportion to the temperature reduction. V

It will not be necessary to change the manual control rod '30 unless there is a substantial change in efiectivestack draft. 'I'Lis may be caused by a substantial drop in temperature This minimum twenty caused by variation in wind conditions.

outside the house or may b caused by wide variations in barometric pressure; or it may be In any event this change is comparatively seldom required and when made is effective for all burner settings. It will be understood that the ordinary user of the stove may not be provided with a draft indicator, but it is possible to reach an approximately correct setting of the manual damper by observation of the flame and by check of the character and temperature of the products of combustion.

Referring next to the form of construction shown in Figures 4 and 5, the operation is substantially the same as that which has been described above in connection with Figures 1 to ,3. In this construction three separate bi-metallic strips are provided so that the damper is not swung but is moved along a line substantially normal to its surface. The thermostatic elements operate in the same manner, however, to move the damper away from the draft outlet under high temperature conditions and to retract it toward the outlet under low temperature conditions.

The form of construction shown in Figures 6 to 8 inclusive, operates in the same general manner in that it serves to reduce the effective flue area. It is not located immediately adjacent the combustion chamber, however, or in that chamber, as are the constructions of Figures 1 to inclusive. This form of construction is preferably placed in the flue pipe or stack several feet away from the stove or heater. The construction shown provides a simple control by which a single damper is automatically adjusted both thermostatically and by variations of relative barometric pressures. The damper 84 and its supporting bi-metallic strip 83 are so located that the damper is swung away from the damper body 18 under high temperature conditions to dampers in th constructions of Figures 1 to 5.

The damper body 18, however, is also directly 1 moved by the barometric control vane 69 which is positively connected to the shaft supporting the damper body 18. It will be understood that this barometric vane 69 is designed to substantially fill the cross-sectional area of its housing 68. Therefore this vane does not in any position allow the entrance of any substantial amount of air into the flue. The communicating chamber 61 merely transmits the pressure or draft in the flue below the damper body 18 to the rear of the barometric vane 69. The opposite face of the vane is subjected to atmospheric pressure'of the room in which the pipe is located. Therefore the movement of the vane 69, in the absence of other factors,'is dependent on the relationship between the draft in the flue and the barometric pressure in the room.

The vane is counterbalanced so that its own weight is not effective in any position to vary response to the difference in pressure upon its opposite faces. The size of the opening behind the room intake air adjuster 15 may be varied to prevent too sudden movement of the vane upon fluctuations in pressure. The adjustable draft control weight 02 serves to place a load upon the barometric vane- 8, which load is variable as desired, but which is constant weight to have a constant effective lever arm regardless of the position of the vane. This'form of construction, therefore, permits an initial adjustment which is dependent upon the effective draft in the stack and which reacts to the difference in barometric pressure between the gases or air in the flue and the air in the room. In addition the damper 84 supported by the rotating damper frame J8 serves to automatically adjust the effective flue opening upon variations in the heat of the products of combustion reaching its bi-metallic strip.

While I have shown certain preferred embodiments of my invention by way of example, it is to be understood that it is capable of further modification and change to meet differing conditions and requirements, and I contemplate such modifications as come within the spirit and scope of the appended claims.

' What is claimed is:

1. In a stove construction, a combustion chamber, a passage for products of combustion leading from said chamber, a damper element within the combustion chamber extending across the entrance to said passage, a heat responsive mounting within the combustion chamber for said element adapted to vary the position of said element upon changes of temperature, a linearly adjustable support for the heat responsive mounting extending into the combustion chamber, and manually operable means for moving said support.

2. In a stove construction, a combustion chamber, said chamber having a port for products of combustion, a damper element within the combustion chamber extending across said port, and a heat responsive mounting for said damper comprising a bi-metallic strip extending parallel to the face of the damper within the combustion chamber whereby the damper is swung toward and away from said port upon variations in temperature.

3. In a. stove construction, a combustion chamber, said chamber having a port for products of combustion, a damper element within the combustion chamber extending across said port, a heat responsive mounting for said damper comprising a bi-metallic strip whereby the damper is swung within the combustion chamber toward and away from said port upon variations in temperature, an adjustable support for the heat responsive mounting, and means for adjusting the position of the adjustable support.

4. In a stove construction, a combustion chamber, said chamber having a port for products of combustion, a damper element extending across said port, a heat responsive mounting for said damper whereby the damper is moved toward and away from said port upon variations in tem-- perature, an adjustable support for the heat responsive mounting, means for adjusting the position. of the adjustable support, a sliding rod carrying the heat responsive mounting. and a handle located exteriorly of the stove for moving said sliding rod.

RQLLAND C. SABINS.

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