US1594074A - Internal-combustion-radiator-unit heating system and method of operating same - Google Patents

Description

F. W. SHUELL ET AL INTERNAL COMBUSTION RADIATOR UNIT HEATING SYSTEM AND METHOD OF OPERATING SAME Filed Sept. 14, 1925 s Sheets-Shut 1 In m \N l J J[ m i 7* 7* I H 1 l lance/T4 60? m, 9km A441! 10m July 27,1926.

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UNITED STATES 1,594,074 PATENT OFFICE- ERAN K W. SHUELL AND ELMER E. LEDBETTER, OF DETROIT, MICHIGAN, ASSIGNORS TO EVERHOT HEATER COMPANY, OF DETROIT, MICHIGALL. A CORPORATION OF MICHIGAN.

INTERNAL-COMBUSTIONRADIATOR-UNIT HEATING SYSTEM AND METHOD OF OPERATING SAME.

Application filed September 14, 1925. Serial No. 56,330.

The invention relates to heating systems of that type employing a plurality of combined convection and radiation units individually operated by internal combustion.

Heretofore systems have been tried in which the individual units have been heated by gaseous fuel, the products of combustion being drawn away through an exhaust conduit. Such systems have, however, proven unsatisfactory and of short life due to various causes among which are, first, lack of efiiciency in extracting the heat from the combustion gases, and second, excessive cor-' rosion caused by the products of combustion; third, the existence of hot spots in the outer surface and consequent danger of fire.

The burning of any fuel having a hydrogen -content results in the generation of water vapor which, when condensed and commingled with other products of combustion such as sulphur dioxide, will produce a highly corrosive agent. This, collecting on the walls of the radiator or the conduit through which the combustion gases are exhausted, will soon destroy the same. On the other hand, if condensation is avoided by the exhaustion of the gaseous products while still hot, this greatly reduces the efiiciency and increases the cost of operation beyond practical limits.

With our improved construction and method of operation, we have overcome the difliculties above referred to, extracting most of the heat from the products of combustion, while avoiding any condensation of water vapor which would cause corrosion.

The broader features of our invention are applicable to systems using various kinds of fuel but we shall specifically describe a system using gaseous fuel.

In the drawings;

Figure 1 is a diagram illustrating the system of our improved construction.

Figure 2 is a vertical longitudinal sec tion taken on the line,22 of Figure 3.

Figure 3 is a cross section on the line 33 of Figure 2.

Figures 4, 5, and 6 are horizontal sections respectively on lines 44, 5-5 and 6-6 of Figure 2.

Figure 7 isa section on the line 77 of.

As has been stated. one of the chief sources of trouble with such a system is condensation of the products of combustion and consequent corrosion of the apparatus. The effort is usually made to secure high efliciency by cooling down the products of combustion so as to extract most of the heat therefrom. Therefore the temperature is dropped below the dew point where condensation occurs and if this is not done, the apparatus is inefficient. 'We have discovered that by limiting the quantity of air originally supplied to the combustion chamber to only that practically necessary for supporting combustion plus a certain proportion of air for preventing condensation in the unit itself and by diluting the products of combustion with more air after most of with an exhaust conduit C from which the products of combustion are discharged by suitable means such as the exhaust fan D. Each unit A comprises an outer casing E within which is arranged a combustion chamber F. This combustion chamber merges into a progressively contracting flue- G preferably leading upward and then downward within the housing E and connecting with the exhaust conduit C. The

combustion chamber as well as the flues G are surrounded by air convection passages" which are open at their lower ends and con-1 nected at their upper ends with a top chamber H discharging preferably laterally through a grid I. The upper wall of the located in one or more of the walls of the chamber. As specifically shown, a series of calibrated ports F are arranged in the front wall F of the combustion chamber. while the bottom wall F and rear walls F are imperforate. The combined'area' of all the inlet ports is predetermined so as to restrict the amount of air entering the combustion chamber to the desired quantity for preventing condensation. The contracting flue G has at its upper end a header 0 which is connected at its opposite ends by transversely extending conduits Pand P with a similar header Q connecting with a downwardly extending and contracting flue G. At the lower end of. this flue G is an enlarged conduit R which communicates with a bottom chamber S to which the exhaust conduit C is connected. There is also arranged in this bottom chamber adjacent to the exhaust conduit-an auxiliary air inlet preferably a series of ports T, T etc., and

' the effective area of these ports can be varied by means of an adjustable valve or damper U. V is a partition or shield which is arranged in front of the combustion chamber F and upwardly extending flue G to intercept the radiant heat of these parts. It also divides the air flue between the combustion chamber and the outer wall of the casing and by reason of the cooler air which will circulate through the outer passage, an abnormal rise in temperature of the outer wall is prevented. In operation, the burners in the various units A are all lighted. but by reason of the thermostatic control of the; valve N the quantity of gas consumed is dependent upon the temperature of the room to be heated. The heat generated by the consumption of the gas and communicated to the gaseous products of combustion is dissipated first through the walls of the flue G to the air in the surrounding chamber. As this surrounding chamber is open at both bottom and topan ascending current of heated air will be formed which will be discharged through the grid I at the upper end of the unit. The tapering form of the flue G provides for con raction in volume due to loss of heat with ut diminishing the velocity of movement through the flue. After reaching the top of the flue G the products are conducted through the header 0 and lateral conduits P and P to the header Q which merges into the downwardly extendscribed and the dilution of the gaseous prod- 1 ucts of combustion are such that when reaching the bottom chamber S the products of combustion are still at a temperature slightly above the dew point so that the water vapor content remains uncondensed. If, however, the products in this condition were drawn outward through a cold exhaust conduit, condensation of the vapor would inevitably result. The condensed water commingling with corrosive products such as sulphur dioxide would soon rust out the conduits and render the apparatus short lived and inoperative. Such result we avoid by commingling with the products of combustion entering the bottom chamber S a sufficient quantity of air to lower the dew point below any drop in temperature which may occur before the products are finally expelled from the exhaust conduit. The amount of air required depends upon conditions of humidity and temperature and we have therefore provided the adjustable damper U for proper regulation. This damper performs the further function of regulating the pressure drop in the chamber S which in turn controls the amount of primary air which is drawn into the combustion chamber. The highest efficiency is produced where this quantity of primary air is only sufficient to support combustion and to avoid condensation within the unit itself. This limits the volume and increases the temperature of the gases while in the unit with the consequent increased heat dissipation from the unit.

A further important feature of our construction is the means for guarding against overheating of any portion of the external surface. The unit is not intended as a stove but as a substitute for a steam or hot water radiator and this is frequently located adjacent to draperies and other imflammable material, therefore the temperature should not at any time exceed 250 degrees F. On the other hand the efliciency is increased by keeping this temperature as near the upper limit as-possible so that it becomes very important to avoid hot spots and to maintain asubstantially uniform temperature in the external casing of the unit. It is also important to avoid loss .ofradiant heat to the exhaust gases and this is accomplished lift) by the arrangement of shields or partitions V and V, the former being arranged between the hottest portion 01'' the combustion chamber and theouter wall of the cas-- mg, and the latter between the combustion chamber and the rear flue for exhaust gases. As a result, the radiant heat intercepted by the shields is dissipated by convection of the air passing through the unit with the double advantage of avoiding hotspots in the external casing or loss of heat in the exhaust products.

To maintain a uniform temperature it is desirable to provide thermostatic control which increases or diminishes the quantity of gas supplied to the unit. As illustrated.

W is a thermostatic unit of any suitable construction which controls a valve- VV' n the gas supply conduit adjacent to the vunit.

' X on the inner side thereof. Thus, the

, unit, such that the amount of air admitted to said unit is limited substantially to that necessary for complete combustion plus the amount necessary for preventing condensation within said unit.

2. The method of operating an internal combustion radiator unit having fuel and air inlets and an exhaust conduit, said method consisting in creating a suction within said exhaust conduit and admitting a variable quantity of auxiliary air into said exhaust conduit to control the suctionefi'ective on said unit whereby an amount of air is drawn through said air inlet sufficient for supporting combustion and preventing condensation within the unit.

3. The method of operating an internal combustion radiator unit having fuel and air inlets and an exhaust conduit for carrying away the products of combustion from said unit which consists in creating a suction within said exhaust conduit for withdrawing the ro'ducts of combustion from said unit an admitting a predetermined amount of air to commingle with the roducts of combustion entering said ex aust conduit whereby the rate of flow of said products'through the unit is such as to dissipate the heat therefrom to lowen. the temperature to near the dewpoint-and the dew point of said mixture is lowered to less than she temperature within the exhaust conuit.

4. The method of operating an internal combustion radiator unit having fuel and air inlets and an exhaust conduit for carrying away the products of combustion which consists in admitting a predetermined amount of air to both said unit and said exhaust conduit, the air admitted to the unit being only sufficient to support combustion and preventcondensation Withiirthe unit and the air admitted to the exhaust conduit being such as to lowervthe dew point of the diluted mixture to less than the temperature thereof in the exhaust conduit.

5. A heating apparatus comprising an internal combustion radiator unit, means for supplying fuel thereto, means for supplying primary air thereto, a casing surrounding said unit and open for the passage of air therethrough to extract the heat from said unit to lower the temperature of' the same to approximately the dew point, a suction conduit for withdrawing the products of combustion from said unit and means for introducing a variable quantity of air into said suction conduit for varying the effective suction-on said unit and thereby regulating the amount of primary air admitted to that necessary for supporting combustion plus an amount sufficient to prevent condensation within said unit. 7 p

6. A heating apparatus comprising an internal combustion radiator unit having calibrated air inlets and a fuel inlet, a casing surrounding said unit and open for the passage of air therethrough to extract the heatfrom said unit, a conduit through which the products of combustion in said unit are withdrawn, means for placinga predetermined suction on said unit so proportioned to said air inlets as to permit the abstraction of the heat from the products of combustion to lower the temperature of the same to approximately the dew point, and means for commingling additional air with said products before exhausting the same to lower the dew point thereof.

7. A heating apparatus comprising an internal-combustion radiator unit, means for supplying fuel to said unit, means for admitting a limited supply of air to support combustion and prevent condensation within the said unit, means for extracting the heat from the products of combustion to lower the temperature of the same to near the dew point, a conduit through which the products of combustion are withdrawn from said unit and means for'commingling additional air with the products of combustion withdrawn through said conduit to lower the dew point thereof below the lowest tem-' perature in said exhaust conduit.

8. A heating apparatus comprising an internal combustion radiator unit, a casing surrounding said unit and open for the passage of air therethrough, a suction conduit through which products of combustion in I said unit are withdrawn, means for prede termi'ning the velocity of travel of sald products through said unit to abstract the heat therefrom to lower the temperature thereof to approximately the dew point, and means for commingling additional air with said products before exhausting the same to lower the dew point thereof.

9. A heating apparatus comprising an in-' ternal combustion radiator unit, an exhaust conduit connected with said unit, means for creating a suction in said exhaust conduit, means for regulating the flow of the gaseous products of combustion through said radiator unit to limit the quantity of air admitted to substantially the amount necessary for supporting combustion and preventing condensation within the unit, means to extract heat from said products to lower the temper-" ature thereof to approximately the dew point thereof, and means for commingling air with said products before exhausting the same to lower the dew point of the mixture.

10. A heating apparatus comprising an internal combustion radiator unit, an exhaust conduit for the products of combustion connected to said unit, means for producing a suction within said exhaust conduit and regulable means for admitting air to commingle with the products of combustion before'exhausting the. same to said conduit whereby the quantity of air for supporting combustion is limited, the speed of flow through the unit is retarded to lower the temperature to approximately the dew point and the dew point of the commingled air and products is lowered to a point below the temperature within said exnaust conduit.

11. An internal combustion radiator unit comprising a combustion chamber, means for supplying fuel to said combustion chamber, means for supplying air thereto, a casing surrounding said unit and open for the passage of air therethrough to extract the heat from said unit, a flue within said casingthrough which the products of combustion in said combustion chamber are withdrawn, a suction conduit connected with said flue and means for admitting a variable amount of air to commingle with the products of combustion in advance of entrance to said suction conduit.

12. An internal combustion radiator unit comprising a casing having air inlet and outlet openings respectively in the lower and upper portions thereof, a combustion chamber within said casing and spaced from the walls thereof, air and gas inlets for said combustion chamber, a progressively contracting vertical flue within said casing spaced from the wallsthereof, an exhaust oonduit connected with said flue and means for admitting auxiliary air to commingle with the products of combustion passing from said flue into said exhaust conduit.

13. An internal combustion radiator unit comprising a casing open for the passage of air therethrough, a combustion chamber therein, means for supplying fuel to said combustion chamber, a flue also within said casing through which the products of combustion are withdrawn from" said combustion chamber, and a shield within the air passage of said casing for intercepting the radiant heat from a high temperature portion of said combustion chamber.

14. An internal'combustion radiator unit comprising a casing open for the passage of air therethrough, a combustion chamber therein, means for supplying fuel to said combustion chamber, means for supplying air to said combustion chamber, a flue also within said casing through which. the prod nets of combustion are withdrawn from said combustion chamber and means for intercepting the radiant heat from said combustion chamber and flue to prevent overheating of said outer casing.

15. An internal combustion radiator unit comprising a casing open for the passage of air therethrough, a combustion chamber therein, means for supplying fuel to said combustion chamber. a flue also within said casing through which the products of combustion are withdrawn from said combustion chamber, and a shield within said air passage between the high temperature portion of said combustion chamber'and said outer casing for intercepting the radiant heat from the combustion chamber whereby excessive heating of any portion of the outer casing is avoided.

16. An internal combustion radiator unit comprising a casing open for the passage of air therethrough, a combustion chamber therein, means for supplying fuel to said combustion chamber, a progressively contracting flue also within said casing and extending downward therein parallel .to said combustion chamber and shields within the air passage for intercepting the radiant heat from the hotter portions of said combustion admitting a variable amount of air to commingle with the products of combustionin advance of entrance to said suction conduit, and means for shielding the outer casing from radiant heat of said combustion chamber to avoid overheating of the casing.

18. A heating apparatus comprising an internal combustion radiator unit, an exhaust conduit connected thereto, means for placing a predetermined suction on said exhaust conduit, 2, burner within said unit having a fuel supply connected thereto, and means for introducing into said unit independently of said burner a predetermined amount of air more than sufficient to support complete combustion and limited to substantially that necessary for preventing condensation within the unit.

19. A heating apparatus comprising an internal combustion radiator unit, a burner within said unit having a fuel supply con nected thereto, means for placing a predetermined suction on said unit to exhaust the products of combustion therefrom, said unit being provided with radiation surface for abstracting the heat from the products of combustion thereby lowering the temperature thereof, and means for introducing into said unit independently of said burner a predetermined amount of air more than suflicient to support complete combustion and limited to substantially that necessary for. preventing condensation within the unit.

20. A heating apparatus comprising an internal combustion radiator unit, a burner within said unit having a fuel supply connected thereto, means for placing a predetermined suction on said unit to exhaust the products of combustion therefrom and inlet means for introducing air into said unit independently of said burner, said unit being provided with radiation surface for abstracting the heat from the products of combustion thereby lowering the temperature thereof, said air inlet means and said suction means being so proportioned that the amount of air drawn through said unit is more than sufficient to support complete combustion and is limited to substantially that amount'necessary for preventing condensation within said unit.

In testimony whereof we afiix our signatures.

FRANK W. SHUELL. ELMER E. LEDBETTER.

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