US2075986A - Gaseous fuel consuming heating apparatus - Google Patents

Description

April 6, 1937. F HENNEBHLE 2,075,986

GASEOUS FUEL CONSUMING HEATING APPARATUS Filed Aug. 30, 1934 l 7d I i Imfenifor 27H21# @50% s A Patented Apr. 6, 1937 UNITED STATES PATENT orificev GASEOUS FUEL CONSUMING HEATING APPARATUS 1 Claim.

w preliminary review of conditions pertaining to this type of heating apparatus.

It is well known that hot water heating plants of the gaseous fuel consuming type operating normally at a radiator temperature of approximately l5 140 degrees Fahrenheit and which are thermostatically controlled to shut off the fuel supply when the room temperature has reached '72 degrees, for example, will continue to maintain the room warm for a very appreciable period after shutting olf the fuel supply and frequently the room temperature will continue to rise during a short period. During that period of shutoff of fuel supply, the water of the plant cools rapidly to a very much lower temperature than of, is true proportionately, of the room temperature. "o This is due to the fact that the water in the radiators has continued to give off heat after the fuel supply has been shut off and, as said water cools in the radiators and while flowing through the return pipe to the boiler, the temperature may have been lowered 2l) degrees in the boiler at the moment of reopening of the fuel supply valve.

During the fuel shut-off period, by reason of free circulation of air in the heating chamber of 5 the apparatus, a very considerable proportion of heat is lost through the chimney flue which also contributes materially to the loss of water temperature.

In the interval between the closing of the fuel supply valve and the attainment of higher temperature of the water after the reopening of the fuel supply valve, the water temperature drops appreciably and the room temperature continues to drop below the fixed minimum at which the valve 45 is reopened and during the interval of restoration of water temperature, I have found in practice that waste of fuel is occasioned by permitting the water temperature to drop appreciably during intervals between water heating periods 50 by complete shut-off of fuel supply.

I have found also that the most perfect combustion of gaseous fuel is attained with maintenance of full fuel supply at the maximum pressure at which the same is fed and that, therefore,

55 the best results are obtained by shutting off the fuel supply to the burners completely instead of partially, as is common practice with gas stoves and to this end, I provide a plurality of groups of burners whereof only a portion is shut off at any time while the remainder continue to function.

One object of the present invention, therefore, is to maintain a part or given proportionl of the burners in full operation while the main source of supply of heat is shut ofi so that the water temperature will drop more slowly and to a lesser degree than in instances where all of the heat is shut off responsively to the attainment of a given room temperature.

A further object of the invention is to control automatically the circulation of air through the heating apparatus or boiler and chimney flue to correspond substantially with the requirements of the fuel supply that is used during the periods of closure or shut-off of the main fuel supply.

Other objects of the invention will be understood from or will be pointed out in the following specication.

In the accompanying drawing illustrating a suitable embodiment of the invention,

Fig. 1 is a fragmentary View partly in elevation and partly in vertical section, of a heating apparatus constructed in accordance with the invention.

Fig. 2 is an inverted sectional View of the fuel consuming burner on the line 2 2 of Fig. l.

Fig. 3 is a fragmentary inverted plan View of the connections between the burner and the source of supply of gaseous fuel.

The heating apparatus may be of any of the conventional types comprising what I term a boiler (I), having what ordinarily is the ash pit (2), and the combination chamber (3), the said pit (2) being referred to hereinafter as the air pit and the chamber (3) as the heating chamber. In coal burning apparatus of this type, a grate (4) is interposed between the pit (2) and the chamber (3) and said grate is employed in part for supporting the gaseous fuel burner (5) of my invention, which is interposed between the pit (2) and the heating chamber (3).

The burner (5) comprises a hollow base portion (6) which is divided into a plurality of compartments or gaseous fuel receiving chambers such, for example, as a main chamber (l) and one or more smaller chambers (8).

A group of Bunsen type burners receives its gas supply from the chamber (1) the burners of said group being indicated in Fig. 2 by the reference source of heat for the apparatus.

The burners (I), of Fig. 2, constitute a secondary group, each of which, preferably, is con- 5 nected with a separate small chamber (8) of the base member (6).

Rigid, and preferably integral, with the base member (6) is a skeleton suspension frame (Il) which also is integral with a substantially cylin- 10 drical flange (I2) and the latter, in the instance illustrated, is integral with the iiat hexagonal flange (I3) which is supported upon the portion of the grate (4) which is retained for that purpose. A sheet metal plate (I4) is disposed upon the grate (4) to completely cover the same in order to prevent passage of any air from the pit (2) to the chamber (3) through said grate. Interposed between said plate A( I4) and flange (I3), is a sheet (I5) of insulating material such as asbestos.

The flange (I2) presents an annular shoulder (I6) upon which a metal plate (I'I) is supported, the latter being provided with openings through which the Bunsen type tubes project to substantially the level of the flange (I3). The receptacle formed by the flange (I2) and the plate (I'I) is filled, preferably, with asbestos cement or other suitable material, to the levelof the discharge ends of the said Bunsen type burner tubes and constitutes a further air seal between the pit (2) and the chamber (3), so that no air may pass from the pit to said chamber (3) except through the air intake openings of the said Bunsen type burner tubes. Said cement ller also serves to preserve the discharge ends of said tubes against burning away.

The admission of air `to the pit (2) is effected through the opening (IB) which is controlled by the damper or valve (I9). The discharge'of gases from the heating chamber (3) to the chimney flue (2|)) is controlled by a damper (2I).

The main chamber ('I) of the burner is connected, by means of a pipe 2 I -a) with a suitable supply of gaseous fuel, such as gas, and said supply is controlled in part by the pressure regulator (22). Interposed between the pressure regulator (22) and the discharge end of the pipe (2 I-a) is a thermostatically controlled valve (23).

An opening (24) in the gas receiving side of the casing of said valve (23), or which may be otherwise arranged between the pressure regulator valve and the said valve '(23), affords a by-pass leading to a gas supply pipe (25) controlled by the manually operable valve (26) and which is connected also with the gas supply pipes (21), (28) and (29) respectively, and thus with the :several smaller chambers (8) of the base member (6) of the burner for supplying gas to the latter.

Each of the pipes (28) and (29) is controlled by a manually operable valve (3B) and (3I), re-

spectively, so that any selected one or more of the burners (I0) may be supplied from the said pipe (25) or the supply to all, thereof, may be shut off by closing the valve (26).

The valve (23) is controlled by the thermostat (32) of the electrically controlled type, in the instance illustrated, which is arranged to cause said valve (23) to be either completely shut off or open wide so that when open, the gaseous fuel will be supplied to the burners at the normal working pressure requisite to the most perfect combustion of fuel in the Bunsen type burners.

The operating lever (33) for the valve (23) is connected also, by means of a link (34), with the valve or damper (I9) controlling the `air supply Cil " numeral (9), said group constituting the main to the pit (2) so that said Valve or damper (I9) will open to admit sufficient air to supply all of the Bunsen type burners when said valve (23) is open and Will cut down the air supply to accord substantially with the needs of the burners (I8) when said valve (23) is closed.

The chimney lue (2U) communicates also with a vertical flue (35) which extends adjacent to the casing of the heater or boiler (I) to a point near the floor of the room in which said heater is located and which provides a secondary air supply for the chimney flue and affords another means of effecting circulation of air in the chamber in which the heating apparatus is located. Said flue (35) is controlled by a damper (33) which may be operated by the thermostat (32) if desired.

The thermostat (32) is also suitably connected with the damper (2|) to operate the same substantially in unison with the valve or damper I8) so that the circulation of gases in the heating chamber will be proportionate to the amount of fuel being consumed in any given period of time.

'Ihe operation of the heating apparatus is as follows:

In the initial starting of the heating plant, an ordinary pilot flame is employed to ignite the burners, the same being introduced, for example through the door of the heating chamber of the apparatus after having opened the valve (26). Thus, the burner or burners (IQ) fed from the pipe (2l) will be ignited and upon opening valves (3|), the remaining burners (9) will also ignite and thus selectively, one, two or three of said burners may be used vas constant heating elements, it being understood, of course, that the arrangement may be varied to increase or decrease the number of burners (IIJ) proportionately to the number of burners (9) included in the burner structure. Obviously, the thermostatically controlled `valve (23) will be opened when the room temperature has dropped to the point fixed by the thermostat (32) and thus the fuel fed to the burners (9) will be ignited to produce the maximum heat intended 'for the apparatus.

As the room attains a temperature in excess of that indicated by the dial of the thermostat (32), the valve (23) will close while the burners (I 0), selected for constant operation, will continue to supply heat and thus prevent the temperature of the water of said heating system dropping rapidly.

Simultaneously with the closing of the valve (23), the valve or damper (I8) and the damper (2l) will also be changed in position to decrease the volume of air fed to the pit (2) and discharged from the heating chamber (3) respectively. By reason of the suction effect of the gaseous fuel discharge nozzle of the selected burners (I0), the main passage of air from the pit (2) into the chamber (3) will occur through the Bunsen type tubes of the burners (I0) and thus the entry of cold air into said chamber (3) will be limited to a very immaterial volume.

The customary ceramic or refractory tile or brick structure into which the burners (9) and (I0) discharge will be employed and will be supported upon the flange (I3) of the burner structure, but said structure is not illustrated herein.

Obviously, the partition walls between the middle burners (l0) and those at either side thereof, shown in Fig. 2, may be omitted and all three of said burners thus fed from the pipe (2l).

The reduction of discharge of gases from the heating chamber (3) by means of the damper (2|) is of importance in that it will prevent the downward passage of cold air from the chimney iiue into said heating chamber, and will also prevent or reduce the loss of heat'l resulting from the discharge of greater volume of gases from the said heating chamber than is supplied to the same from the pit (2).

In the event that the invention is applied to a steam generating plant, (the boiler (i) being illustrative of either a water heating or steam generating element), a steam pressure responsive means for controlling the valve (23) and the several dampers is provided in place of the thermostat and to this end I have illustrated an alternative device comprising the bellows-member (3l) disposed in the boiler (I) which actuates the plunge (38). The latter bears at its upper end against the lever (39) pivotally mounted between its ends on the support (40). The said plunger actuates the said lever against the action of the weight (4l).

In the event that steam pressure control is substituted for the thermostat control, the lever (39) will be connected at its ends with the chains or cables now shown to be actuated by the thermostatic means.

Inasmuch as steam attains a given pressure at a certain temperature, the pressure responsive means are the equivalent of the thermostatc means illustrated and described since both are temperature responsive.

It will be noted also that when all burners (9) and (IU) are in operation, there is no source of supply of air to the heating chamber except as to such surplus thereof as may pass through the openings in the lower ends of the burner tubes for admixture with the gaseous fuel. Consequently, the said heating chamber will be filled 40 quickly with gaseous products of combustion of high temperature and in consequence of the very limited supply of gases to said heating chamber, the ow of gases through the chimney flues will be limited to the same extent so that there will be no waste of fuel to heat surplus air discharged through said chimney flues. This arrangement is very effective to save fuel and constitutes a very important feature of the invention.

I claim as my invention:

A heating apparatus comprising an air pit, a combustion chamber, an air intake port 'for the air pit, a damper controlling the same, an exhaust flue from the combustion chamber, a damper controlling the same, a gaseous fuel burner disposed between the air pit and the combustion chamber and comprising tWo sets of burners each including a gaseous fuel supply nozzle and a burner tube for each nozzle projecting above the same, air ducts leading from the air pit into the said tubes and constituting the sole connections between the air pit and the combustion chamber and adapted to provide only sufficient air for admixture with the gaseous fuel to produce substantially perfect combustion, connection between each of the said respective sets of nozzles and a source of gaseous fuel, temperature responsive means including a Valve for shutting oif the supply of gaseous fuel to one of said sets of nozzles when the temperature controlling the operation of said temperature responsive means has attained a predetermined high point, connection between said temperature responsive means and said dampers and controlling `said respective dampers for disposing the `latter, simultaneously with shut oi of said gaseous fuel supply to one'set of burners to restrict air supply to the air pit and exhaust of gases from the combustion chamber respectively, to accord substantially with 'the volume of air required to supply the other set of said burners.

FRANK HENNEBHLE.

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