US2349876A - Air intake governor for heating devices - Google Patents

Description

Search Room May 30, 1944. R. MARTIN 2,349,876

AIR INTAKE GOVERNOR FOR HEATING DEVICES Filed Aug. 16, 1941 s Sheets-Sheet 1 INVENTO ATTbRNEY May 30, 1944.

R. MARTIN AIR INTAKE GOVERNOR FOR HEATING DEVICES Filed Aug. 16, 1941 3 Sheets-Sheet 2 INVENTOR fiusse/l Mar/in.

ATTONEY I Search Roo y 1944- R. MARTIN 2,349,876

AIR INTAKE GOVERNOR FOR HEATING DEVICES Filed Aug. 16, 1941 3 Sheets-Sheet 3 IENTOR Fusswel/ Nerf/h A! ZRNEY [I stttstous Built-5.;

7 Patentetl May 30, 1944 Search Room AIR INTAKE GOVERNOR FOR HEATING DEVICES Russell Martin, Wichita, Kans., assignor to The Coleman Lamp and Stove Company, Wichita, Kana, a corporation of Kansas Application August 16, 1941, Serial No. 407,156

15 Claims.

This invention relates to fuel burning appliances and particularly to an air intake governor therefor.

In the use of appliances having fuel combusting burners many attempts have been made to control the draft, supplying combustion supporting air to the burner. The usual practice has been to employ the pressure differential be tween the interior of the device and exterior atmospheric air to actuate some sort of damper attempting to reduce a variable excess draft to an operating draft which will ratio interior pressure to atmospheric pressure so that substantially the amount of air needed for efficient combustion will be supplied.

Frequently a damper is introduced within the hot and sooty vents needful for exhausting the products of combustion. Movable parts of this damper device often become fouled with carbon deposit and corrosion so that it fails to respond quickly, and at times may completely fail causing dangerous living conditions within the house where the appliance is used. As a matter of practice for safety purposes such dampers are usually limited to eighty per cent closure and are, therefore, limited in range of control and inaccurate under some conditions.

It is also common practice to use a damper device to admit atmospheric air directly into the flue vent thus reducing the flow of air through the burner. This has in a measure compensated for the wide variation in chimney drafts, but due to gusty winds and variable weather conditions these "air regulators which operate through a very limited range, are often not sufficiently accurate to effect high efficiency in the burner operation. In certain types of heating equipment they also exhaust from the space being heated a portion of the warmed air which must be replaced by cold air infiltrated from the outside thus further reducing effective efficiency.

Air intake controls have also been used, but these have not been automatically coordinated with the variations of natural chimney draft, so that a substantially constant and uniform supply of combustion supporting air for the burner has not been obtained.

Mechanical devices, such as electrically operated blowers, have also been employed in an attempt to secure uniform flow of air to the burner. Since these of necessity must be operated in connection with the variable natural draft produced by the chimney vents the combined result has been a variable air supply for the burner.

It is my belief that my invention is a very obvious improvement upon all devices hitherto used for this purpose because it does not attempt to control an interior pressure (as others have done) to effect the desired pressure ratio with exterior atmospheric air to create a uniform draft, but it does maintain a substantially uniform pressure differential between two chambers having restricted passage between them through which combustion supporting air flows.

Thus it effects a substantially constant differential of pressure between certain areas within the appliance which pressure differential determines the amount of combustion supporting air passing through the appliance.

The principal object of this invention, therefore, is to provide a device which will deliver to the burner of a fuel burning appliance a substantially constant and uniform supply of combustion supporting air regardless of chimney draft variables and also regardless of any variable affecting the flow of atmospheric air to the appliance.

Other objects of the invention are to provide an air intake governor which can be readily built into small household appliance thus producing a desirable unitary structure; to provide an air intake governor which is adapted to factory adjustment for the burner employed, which adjustment is not affected by the variable excess chimney drafts encountered when the appliance is installed for use; to provide an air intake governor which does not have to be readjusted when a mechanical forced draft device is used in combination with natural chimney draft; to provide an air intake governor adapted to coordinated control with the fuel feeding device of the appliance to secure maximum efficiency at all burning rates; and to provide an air intake governor that is simple and inexpensive to manufacture.

It is also an object of the invention to provide an air intake governor adapted to coordinated control with the fuel feeding device of the heating appliance.

In accomplishing these and other objects of the invention, as hereinafter described, I have provided improved structure, the preferred form of which is illustrated in the accompanying drawings, wherein:

Fig. 1 is a plan view of a floor furnace embodying the features of the present invention, a

part of the combustion chamber being broken away to better illustrate the construction.

Fig. 2 is a vertical section through the lower gortilon of the floor furnace on the line 2-2 of Fig. 3 is a vertical cross-section through the furnace on the line 33 of Fig. 1, the air intake governor being shown in elevation.

Fig. 4 is a fragmentary cross-section through the furnace on the line 4-4 of Fig. 1.

Fig. 5 is a cross-section through the air intake governor on the line 5--5 of Fig. 6.

Fig. 6 is a central longitudinal section through the air intake governor.

Fig. '7 is a cross-section on the line 1-4 of Fi 6.

Fig. 8 is a perspective view of the parts of the air intake governor shown in disassembled spaced relation.

Referring more in detail to the drawings:

I designates a heating appliance embodying the present invention and which may be an oil burning floor furnace, however, it is to be understood that the invention is applicable to any type of heating appliance employing a combustion or burner chamber requiring a controlled supply of combustion supporting air for maintaining maximum efficiency.

The floor furnace illustrated includes an outer casing 2, adapted to be suspended in a floor opening 3 and which has opposite side walls 45 and 6--'| and a bottom 8, the top being covered by a floor grill 9. Supported within the outer casing 2 is an inner casing l0, having vertical walls spaced from corresponding walls of the outer casing to provide downdraft air passages ll' wherethrough air to be heated is circulated from the room and moved upwardly through the inner casing in heating contact with a heater unit l2 and returned to the room through the grill 9.

The heater unit l2 includes a combustion chamber l3 separate from a burner or air supply chamber l4 by a transverse partition I5. The partition i5 has a depressed bottom portion 16 at a side thereof which registers with the lower portion of a flue outlet ll extending through the inner and outer casings and adapted to be connected with a vent or chimney by means of a smoke pipe (not shown). Supported in an opening at substantially the center of the partition is a chamber or burner pot l8 which, in the illustrated instance, has a cylindrical wall IS, a closed bottom 20, a low fire ring 2| spaced from the bottom, and a high flre ring 22 seated on a peripheral flange 23 secured to the partition l5. Fuel is supplied to the burner pot by way of a pipe 24 having connection with a constant level and fuel control valve 25 which in turn is connected by a pipe 26 with the burner pot. The fuel control valve 25 is regulated by a rod 21 which extends upwardly within one of the downdraft passages II and terminates in a handle 28 adjacent the grill so that when the grill is removed the rod may be rotated thereby to adjust the amount of fuel admitted to the burner pot.

Combustion supporting air is admitted under restriction to the chamber or burner pot l8 from the air supply chamber l4 through restricting openings 29 which are provided in the cylindrical wall l9, as best shown in Fig. 4, the supply chamber being provided with an air inlet opening 30 in the wall thereof so that a portion of the air circulated through the downdraft passages is admitted to the supply chamber responsive to draft.

Heating appliances of the character described operate most efficiently at a predetermined draft or pressure differential but when installed there is no assurance that the device will be operated at the desired draft for the reason that it may be connected with a chimney having a draft greatly in excess of that required, or the chimney may have barely sufficient draft to support combustion. It is true that a draft control is usually connected in the smoke pipe so as to admit a sufficient amount of exterior air to the chimney in such a manner that the effective draft approximates the predetermined draft but, as above pointed out, such regulators do not operate satisfactorily and are not sufiiciently sensitive to maintain the predetermined draft for which the appliance is designed.

While the present invention may contemplate use of a draft regulator in the smoke pipe in order to maintain roughly an approximate draft in the heating appliance, I provide the heating appliance with an air intake governor which is designed to operate automatically responsive to pressure differential between the combustion chamber and the air supply chamber and which is adapted to control automatically the inlet of air necessary to maintain efflcient combustion at the pressure differential or draft for which the heater was designed and to maintain this predetermined draft, regardless of varying chimney draft.

In carrying out the invention, the opening 30 is located opposite to the flue connection H, as shown in Figs. 1 and 3, and inserted therein is an air intake governor 3| which forms a unitary part of the heating appliance.

The air intake governor is best illustrated in Figs. 5 to 8 inclusive, and includes a shell 32 having a cylindrical wall 33 of suitable diameter to be received snugly within the opening 30. The inner end of the cylindrical wall is closed by a head 34 having an opening 35 therein registering with the depressed bottom portion l5 of the partition IS. The opening 35 is encircled by a flange 36 which extends into an opening 31 formed in the offset portion 38 of the partition as shown in Fig. 3. The op osite end of the shell is closed by an inset head 9 having a flange portion 40 engaging the inner face of the annular wall 33 and which is provided with a laterally extending rim 4i abutting against a corresponding rim 42 on the shell, as shown in Fig. 6. Air is admitted to the interior of the shell through a substantially sector-shaped opening 43 that is formed in the head 39 and which is of sufficient capacity to pass adequate combustion supporting air to the air supply chamber by way of openings 44 formed in the cylindrical wall 33. Fixed to the inner face of the cylindrical wall 33 and extending inwardly toward the axis of the shell is a partition 45. The partition 45 is located so that it extends from one radial edge of the air inlet opening to the head 34 and cooperates with a vane 43 in dividing the shell into low and high pressure chambers 41 and 48, the low pressure chamber 41 being connected with the combustion chamber through the opening 35 and the high pressure chamber being connected with the air inlet opening 43 and outlet openings 44.

The vane 46 closely conforms to the walls of the shell and is mounted on a shaft 49 located in the axis of the shell and journalled in suitable bearing openings 50 and 5| formed in the heads 34 and 39. The vane 46 is, therefore, adapted to swing within the shell responsive to pressure differential in the respective chambers. For example, should the pressure in the combustion chamber become less, the vane will swing in the direction of the opening 35 and should the pressure increase in the combustion chamber the vane will swing in the opposite direction responsive to a weight 52 attached to an endless chain 53 operating within the groove 54 of a pulley 55 attached to the outer end of the shaft 49.

In order to control the air intake responsive to a predetermined pressure differential in the supply and combustion chambers, the shaft 49 carries a shutter 56 comprising a substantially semicircular disk having a radial edge 51 thereof connected with the adjacent edge of the vane 46. The shutter 56 moves in close relation with the inner surface of the head 39 and in valving relation with the air inlet opening 43. Thus the effective area of the inlet opening is dependent upon a predetermined pressure differential between the high and low pressure sides of the vane as set by the weight 52. In order to limit maximum movement of the vane the shell is provided with stops 58 and 59 respectively engaged by the vane and the shutter.

It is essential that the vane and shutter be initially counterbalanced prior to application of the weight 52 so that positioning of the shutter is the result of balancing the differential forces acting on the vane with the weight 52. Therefore, I provide the shaft with an arm 60 having a weight 6|. The weight has a relatively large axial opening 62 for adjustable mounting thereof on a stud 63 projecting from the arm 60, the weight being retained in adjusted position by a nut 64 threaded on the stud and arranged to draw a washer 65 into clamping engagement with the weight and the weight into clamping contact with the arm 60, the relative diameters of the opening in the weight and stud being such as to provide adjustment necessary in effecting the proper counterbalance. It is obvious that by providing a weight 52 of proper size, the vane may be maintained in such a position that the desired amount of air is admitted to the inlet opening of the supply chamber for maintaining a predetermined draft or pressure differential.

Owing to the fact that the air intake governor is located in the path of the combustion supporting air supply, it is maintained in relatively cool condition so that close tolerances may be effected between the shell and the moving parts of the governor. Also there will be no accumulations of soot or the like to clog the operation thereof. Further the parts may be of small size and capacity because the air is relatively cool and of small volume.

The heater will operate at maximum efficiency at a given burning rate, but if the burning rate is changed it is desirable to change the differential pressure. This is accomplished by varyin the effective force or leverage of the weight 52 on the pulley 54 responsive to change of the fuel valve setting.

The head 39 carries a collar 66 in encircling relation with the shaft to form a pivotal support for an arm 61 whereby the arm is free to pivot about the axis of the shaft without interfering with freedom of the governor vane. Carried by the free end of the arm 61 is a stud 68 journalling an idler pulley 59 and having a peripheral groove therein to accommodate the chain 53. Fixed to the stud 68 is a yoke H having connection with a cam 12 on the valve rod 21 through a flexible connection 13. The flexible connection 13 operates over a guide pulley 14 fixed to a bracket 15 whereby the end of the flexible connection, which is attached to the cam, is supported in a horizontal plane and the other end is supported on a plane extending through the axis of the idler pulley 59. With this arrangement, manipulation of the valve rod causes movement of the idle pulley in an are about the axis of the governor shaft so as to vary the leverage of the weight 52. For example, when the weight 52 is depending tangentially of the pulley 54, the weight 52 exerts maximum leverage on the pulley so that a greater differential force is required to move the shutter toward closed position and a greater differential effects increased flow of air into the supply chamber to maintain the proper air and fuel ratio for maximum efficiency. When the valve rod is rotated in a counter-clockwise direction to throttle the feed of fuel to the burner pot, the idler pulley is moved to the right, Fig. 1, so that the effective leverage for the weight 52 on the pulley is lengthened with the result that the governor will be actuated by a higher pressure differential and more air will be admitted to the burner pot to maintain the proper ratio with the increase of the fuel feed.

From the foregoing it is obvious that I have provided a heating appliance such as a floor furnace with an air intake governor forming a unitary part thereof and which is capable of maintaining a constantly uniform draft or pressure differential regardless of excess variation in the chimney draft. It is also obvious that the pressure differential maintained by the air intake governor is readily coordinated with the fuel adjustment so that the draft or differential is regulated in conformity with the burning rate of the fuel to maintain maximum efllciency under all operating conditions.

What I claim and desire to secure by Letters Patent is:

1. In a fuel burning appliance, the combination of a combustion chamber having a variable internal pressure, an air supply chamber having an inlet for exterior air, means for supplying fuel to the appliance, means responsive to pressure differential between said chambers for governing admission of air through said inlet for maintaining a predetermined rate of air flow through said appliance, and means for changing the rate of air flow responsive to change in rate of fuel supply.

2. In a fuel burning appliance, the combination of a combustion chamber having a connection adapted to be connected with a flue for effecting variable pressure in the combustion chamber, an air supply chamber having an inlet for exterior air, means for supplying fuel to the heating appliance, means responsive to pressure differential between said chambers for governing admission of air through said inlet for supporting combustion of the fuel, means for controlling the fuel supply, and means connected with the fuel control means for changing the pressure differential.

3. In a fuel burning appliance, the combination of a combustion chamber having a connection adapted to be connected with a flue for effecting variable pressures in said chamber, a

burner having connection with said chamber, a

supply chamber for admitting combustion sup porting air to the burner and having an air inlet, a movable vane responsive to pressure differential in the respective chambers, a throttle for the air inlet actuated by the vane, means for applying a force to the vane to balance the force of the required differential, means for supplying fuel to the burner, means for controllin the fuel supply, and means responsive to movement of the fuel control means for varying the effect of the force applying means.

4. In a fuel burning appliance, a combustion chamber having a flue connection through which variable pressures are effected in said chamber, a burner associated with the chamber, a supply chamber surrounding the burner for admitting combustion supporting air and having an air inlet, a movable vane responsive to the variation of the differential pressure in th respective chambers, and means connected with the vane for valving the air inlet to said air supply chamber responsive to movement of the vane.

5. In a fuel burning appliance, a combustion chamber having a flue connection adapted to be connected with a flue for effecting variable pressures in said chamber, a burner having connection with said chamber, a supply chamber surrounding the burner for admitting combustion supporting air and having an air inlet, a vane responsive to variation of the differential pressure in the respective chambers, a throttle for the air inlet actuated by the vane, means for applying a predetermined counteracting force to oppose the higher of said pressures to effect the desired pressure differential, and means for varying the counteracting force to vary th pressure differential.

6. In a fuel burning appliance, a combustion chamber containing variable pressures when appliance is in operation, a burner having connection with said chamber, a variable supply chamber for admitting combustion supporting air to the burner and having an air inlet, said burner forming a restricted air flow connection between said chambers, a vane responsive to differential of pressures in the respective chambers, a throttie for the air inlet actuated by the vane, and a force applied to the vane for yieldingly retaining the vane in position to effect a wide open air inlet when the pressure differential is less than the predetermined requirement and to permit a partial closing of said air inlet when the predetermined pressure differential is exceeded.

7. An air inlet governor including, a cylindrical housing having an air inlet opening at one end and a due connecting opening in the other end, an intermediate air outlet opening in the cylindrical wall thereof and adapted to be connected with the air supply chamber of a heating appliance, a shaft journalled coaxially of the housing, a vane fixed to the shaft and having the respective sides responsive to pressure acting through the air outlet and through the flue connecting opening. a partition cooperating with the vane, a weight attached to the shaft for effecting rota tion of the shaft in one direction, and a shutter on said shaft controlling the effective area of the air inlet opening.

8. An air governor including. a housing having an air inlet opening. an opening adapted to be connected with a variable pressure zone and an air outlet opening adapted to be connected with the air supply chamber of a fuel burning appl ance, a shaft journalled in the housing, a vane fixed to the shaft and having the respec tive sides subjected to pressure of said air supply chamber acting through the air outlet and through the opening connected with the variable pressure zone, and means actuated by said shaft controlling effective area of the air inlet opening.

9. An air governor including, a housing having an air inlet opening, an opening adapted to be connected with a variable pressure zone and an air outlet opening adapted to be connected with an air supply chamber of a fuel burning appliance, a shaft journalled in the housing, a vane fixed to the shaft and having the respective sides subjected to pressures of said air supply chamber acting through the air outlet and through the opening connected with the variable pressure zone, means actuated by said shaft to throttle the air inlet opening, a pulley on the shaft, a flexible member connected with the pulley, and a weight attached to the flexible member for effecting rotation of the shaft in one direction.

10. In an apparatus of the character described, an air chamber subject to variable pressure, a supply chamber for admitting combustion supporting air, a fuel burning means in said chamber, the supply chamber having a restricted connection through the fuel burning means with the chamber subject to variable pressure and having an inlet, means controlling said inlet, and means having connection with pressures in the respective chambers and operably connected with the control means for controlling said inlet responsive to pressure differential in the respective chambers.

11. In a fuel burning appliance the combination of a combustion chamber having a flue connection adapted to be connected with a flue for effecting variable pressures in said chamber, a burner having connection with said chamber, a supply chamber for admitting combustion supporting air to the burner and having an air inlet and providing an unrestricted air flow from said inlet to the burner whereby the pressure at the burner is substantially that of the supply chamber, a movable vane having a side subject to pressure in the air supply chamber and having a side subject to pressure in the combustion chamber whereby the vane moves responsive to pressure differential in the respective chambers, a throttle for the air inlet actuated by the vane, and means for applying a force to the vane to balance the force of a desired operating differential. a

12. In a fuel burning appliance, the combination of a combustion chamber having a variable internal pressure during operation, a supply chamber for admitting combustion supporting air and having an inlet for exterior air, means including a burner separating said chambers and providing a restricted air flow connection between said chambers, and means responsive to pressure differential between said chambers for governing the flow of air through said inlet.

13. A governor of the character described including a housing having an air inlet in an end thereof and an air outlet in a side thereof adapted to be connected with the air supply chamber of a fuel burning appliance, said housing having an opening adapted to be connected with a combustion chamber, means separating said air inlet and outlet from said opening including a fixed partition, 9. vane pivoted at one edge of the partition and adapted to swing between the outlet and said opening responsive to pressure differential effected through said air outlet and said opening, and a shutter having rigid connection with the vane and movable over the inlet opening.

14. An air governor including a housing having an air inlet, and an air outlet opening adapted to be connected with the air supply chamber of a fuel burning appliance, said housing also having a fiue connecting opening, a shaft journalled in the housing, a vane aiiixed to the shaft and having the sides thereof subjected to pressure acting through the air outlet and through the flue connecting opening respectively, means actuated by said shaft for controlling the effec tive area of the air inlet opening, balance means for said vane, and separate balance means for providing the force of the required differential.

15. An air outlet governor including a cylindrical housing having an air inlet opening at one Search Room end and a flue connection opening at the other, said housing having an intermediate air outlet opening in the cylindrical wall thereof and adapted to be connected with the air supply chamber of a fuel burning appliance, a shaft Journalled coaxially of the housing, a vane fixed to the shaft and having sides responsive to pressures acting through the air outlet and through the flue connecting opening respectively, a shutter on said shaft controlling the effective area of the air inlet opening, a weight for balancing the vane and shutter, a member on the shaft having an arcuate portion, a flexible connection operating over the arcuate portion, and a weight on the flexible connection for balancing a predetermined resultant force of said pressures.

RUSSELL MARTIN.

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