US 2641244 A
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Description (OCR text may contain errors)
June 9, 1953 N M. J. MAIER 2,641,244
COMBINATION RANGE Filed Dec.v 6, 1948 2 Sheet-Sheet 1 June 9, 1953 Filed Dec.
2 Sheets-Sheet 2 9 l i, 0, 4 @u j d l z A WJ/, Mi m l Patented June 9, 1953 UNITED STATES PATENT OFFICE VC)lVlI`l`TiYI`ION RAG Michael J. MaiemBeaver Dam, Wis., assigner to Malleable Iron Bange Company, Beaver Dam, Wis., a lcorporation of Wisconsin Application December 6, 1948, Serial No. 67337181 Y 3 Glaims. l
This invention relates to a combination range, such as a gas and coal-wood combination, or an electric and coal-wood combination.
Gas and electric ranges are generally recognized as being superior to the usual coal-wood range for cooking, but the substitution of one for the other is not always practical, especially in rural areas, where the Vcoal-wood range also provides means for heating water.
It is an object of this invention to provide a combination range including a water reservoir whereby the coal-wood portion can be used for water heating, and for some cooking operations, and whereby the electric or gas portion can be used for all cooking operations, including baking and broiling.
It is a further object of this invention to provide a combination range wherein the water reservoir is located between the coal-Wood portion and the electric or gas portion, and thus serves to maintain the latter portion at a reduced temperature. Considerable diiculty has been experienced in the operation of the gas burners of a combination range due to the heat developed by the coal-wood portion and its eiiect on the air thatris drawn into the gas burners. This irregularity in operation is overcome in the present construction, due to the fact that the water reservoir absorbs heat from the fire box, and serves to maintain a more uniform temperature.
Although the same difficulty is not experienced ii electric heating elements are substituted for gas burners, it is equally important to maintain all parts of the electric portion at as loW a temperature as possible, due to failure of insulation and of soldered electrical joints which will occur if the parts are permitted to lget too hot. As a matter-of fact, it is oftentimes diflicult to design a combination coal-wood electric range which will meet thefrequirements oi the Underwriters Laboratories, Vdue to the excess temperatures developed by the coal-wood portion. With the present construction, however, it has been found that it is possible to maintain the electric portion within the maximum temperature requirements Without resorting to more costly expedients. Y
It is a still further object of this invention to provide a combination range in which the reservoir and coalwood heating means therefor are so arranged as to heat the Water in the reservoir f' quickly and efficiently while at the same time avoiding the possibility of having the water boil away. In this connection it can be pointed out that the usual reservoir is located at some distance from the firebox. In some instances, the
reservoir is provided with water heating coils which extend down into the fire box, which construction isgobjectionable for the reason that the water will be heated to the boiling point in a short period of time, and will subsequently boil away unless carefully watched. Where a less efcient heating means is desired, in order to obviate this difficulty,l theproducts oi combustion are caused to .pass by the reservoir, but in this arrangement it takes too long to bring the water up to the desired temperature.
In the present invention, the reservoir is disposed alongside the re box, and is comparatively deep, the lire rbox in its entirety being disposed well above the bottom oi the reservoir.
Thus, the heat is applied to the reservoir at an intermediate portion, and when the water level drops below the area of heat application, there will not be suilicient heat transfer to cause the water to boils On the other hand., this small amount of water vwill be -maintained at a sufiiciently high temperature as to be useful, it being assumed that the water was initially heated when the reservoir contained more water.
IIn other words, with the arrangement provided herein, the heating of the water, that is, the amount of heat transferred to the water, is controlled in part by the amount of water in the reservoir. Thus, the operation is automatic insofar as attention is required to prevent the boiling away of water. At the same time, the fact that a small amount of water will not be eiciently heated does not detract from the utility of providing a large capacity reservoir for the reason that once the reservoir is lled and the water brought up to temperature, the full amount of water in the reservoir is available.
The reservoir, being laterally displaced from there boxrece`ives its heat from the cast iron wall of the re box primarily by radiation, which is' of advantage since the reservoir chamber is thus not directly exposed to the iiames, or hot gases, or to any such source of heat as is likely to cause warping or oxidation of the metal ci which the reservoir is formed. in this connection I pre* fer to provide a partition or barrier between the reservoir and the wall of the 're box, the main purpose of which 'is to Vseal off the area in which the reservoir is located 'from smoke, soot and ash, but which also prevents damage to the reservoir in the event that all of the water should evaporate due 'to failure to reiill the reservoir over a period of several days.
A still further object is to provide a reservoir which is removably mounted in a stove so that it may be removed and cleaned. The presence of the aforementioned partition further facilitates the removal for the reason that otherwise, the exterior of the reservoir would become soot covered. The difficulty in handling a comparatively large soot covered reservoir would discourage one from removing the reservoir for the purpose of cleaning the interior thereof.
Still another object is to provide a combination range of the type indicated in which the reservoir serves to modify the temperature of a portion of the stove top, to the end that a definite area of the stove top is provided on which dishes can be placed for Warming or for maintaining food warmed preparatory to serving or in between servings.
Other objects, features and advantages will become apparent as the description proceeds.A
With reference now to the drawings in which like numerals represent like parts; Y Y
Fig. 1 is an elevation of a preferred embodiment of my invention, the figure being partially in section;
Fig. 2 is a section taken substantially along line 2-2 of Fig. 1;
Fig. 3 is an enlarged sectional view showing the means for suspending the upper edge of the right wall of the reservoir, and
Fig. 4 is an enlarged section showing the means for suspending the upper edge of the left wall of the reservoir.
As shown in the drawings, the combination range includes a base I on which the range is supported, the main portion of the range comprising end walls II and I2 and a back wall I3. Other structural members I4 may also be provided. The range is divided generally into a gas portion and a coal-wood portion 2|, the gas portion comprising the right-hand half of the range and the coal-wood portion comprising the left-hand half. The front of the gas portion comprises a control panel I5, an oven door I6 and a broiler drawer panel I1. The front of the coal-wood portion comprises similai-ly disposed elements of which only fragments of the door I8 and the drawer panel I9 are shown in Fig. 1, the top panel which is similar to the panel I5 not being shown.
Within the range are disposed various partitions and plates including a partition 22 which divides the gas portion from the coal-wood portion. Plates 23 and 24 are vertically disposed in the coal-wood portion and a fire box 25 having conventional grates 26 is mounted from the plates 23 and 24 by means of suitable brackets 21. The brackets maintain the exterior side walls of the re box in spaced relationship with respect to plates 23 and 24. Thus a space 28 'is provided at the right of the nre box, and a similar space at the left. A draft opening 29 is provided in plate 23, and a fiue opening 30 is provided in the back wall I3. An ash receiver 3I is removably mounted below the grates 26, and access to the ash receiver is provided by means of the door I8. A sub-bottom 32 cooperates with the plates 23 and 24 to provide a closed compartment 33 in which the fire box and its cooperating elements are located. A removable malleable iron top 36 is provided for the-compartment 33. Thus the products of combustion, which escape through the ue opening, are confined to that portion of the range'referred to as compartment 33.
The reservoir is provided with a top plates 31 which is secured to the upper edge of the reservoir by bolts 39. The top plate ksupports a removable cover 38. The right hand edge of the top plate 31, as viewed in Fig. 1 rests on an angle iron 43 which is secured to the partition 22. The left side rests on the top of the plate 24, these details being shown in Figs. 3 and 4.
The right hand edge of the stove top 36 rests on a depressed portion formed in the left hand edge of the top plate 31 and the remaining edges of the stove top 36 may be supported by suitable angle irons 40.
As shown in Fig. 4, a sheet 5I of asbestos overlies the upper portion of the plate 24. This sheet of asbestos extends downwardly to about the bottom of the re box 25, and serves to protect the plate 22 from undue heat. A second plate 52 overlies the upper portion of the asbestos sheet 5I at the point above the fire box where it is exposed to smoke and flame. A swing down faucet may be provided in the bottom of the reservoir if it is preferred to remove the water this way rather than by dipping.
In operation, the reservoir is lled through the removable cover 38, and the water therein is heated by the re in the fire box 25. The hot water may be dipped out of the reservoir through the removable cover 3B or drawn from the aforementioned faucet. The heat is transferred to the reservoir primarily by radiation across the space 28, one wall of which space constitutes the fire box and the other wall of which constitutes the elements 24 and 5I. The wall of the reservoir is positioned more or less in contact with the plate 24 with the result that the heat received by the plate 24 is transmitted to the wall of the reservoir and thence to the water when the reservoir is full. The reference numerals A, B and C designate points or levels on the wall of the reservoir. That portion of the reservoir wall which lies between points A and B is designated by the reference numeral 4I and constitutes a heating plate for heating the water which is in contact therewith. However, when the water level in the reservoir drops below point B, a much smaller amount of heat will be transmitted to the water, and when the water level drops down to about point C, the amount of heat transmitted to the water will be practically negligible. Thus an automatic regulation of the heat transfer is provided which depends primarily on the water level. A comparatively high rate of evaporation which takes place only when the water level is high, will automatically lower the water" level to such a point that the rate of evaporation is considerably cut down. Thus, the likelihood of warping or other damage to the reservoir by having the water evaporate completelyis considerably reduced. The presence of the plate 24 and the asbestos sheet 5I further serves to protect the reservoir in the event that the water should completely evaporate over a period of several days, due to failure to refill the same. However, the likelihood of having this occur is almost negligible due to the fact that the fire box is provided primarily for the purpose of heating the water, and one would not ordinarily built a fire in the fire box without seeing to it thatthe reservoir is also full.
The principal diiculty to be guarded against in combination ranges is that of having the water boil away before the iire goes out. This often occurs in the usual range where the arrangement is such that the water in a partially filled reservoir is subjected to heat transfer at substantially the same rate as it is When the reservoir is'full. In the present range, even when the reservoir is full, it has been found that-the'water was heated not to the boiling .point throughout :a `.tenhou test iiring period. l
Two Itests were run on the above described range, the vreservoir being `about one-third ifull in the Vrst test and completely lfull in the second test. 'in the iirst test, the 'water in the parta-lily filled reservoir was brought upto a substantially constant temperature -of 1150 after six hours and the average temperature on vthe (exterior 'surface of the -re lbox was T36YD -F. during this six-hour period. In the second test, the water in the completely filled reservoir was brought up to a substantially constant temperature of 174 after seven hours and the average nre box temperature during this seven hour period was '740 F.
To maintain the water in the partially iilled reservoir at 150 required an average fire box temperature of 750 F., while to maintain the water in the completely nlled reservoir at a substantially constant temperature of 175 required an average temperature of 690 F.
The foregoing tests show that in the present construction, not only is the efficiency of heat transfer cut down by a drop in the water level, but it also shows that with the drop in the water level, the heat loss more than ofsets the amount of heat received by transfer, with the result that a substantially lower temperature equilibrium is reached when the water level drops below the heating plate lll. Thus, evaporation is reduced to an even greater extent since vapor pressure is not proportional to temperature. In other words the rate of heat loss although it may vary with the quantity and temperature of the water in the reservoir, is believed to be determined more or less by the structure of the range, that is, the manner in which the reservoir is mounted, with the result that the comparatively large variation in rate of heat transfer, as determined by the water level, causes the variation in equilibrium temperature above referred to.
The fact that the lower part of plate and thus the lower part of the reservoir is exposed to the cold air entering into the lower part of compartment 33 through the draft 29 is believed to be an important factor in providing the requisite degree of heat loss. In this connection it will be observed that the side walls of the ash receiver 3l are .spaced from the Walls of the compartment 33 which permits a circulation of air between the lower part of partition 24 and the ash receiver. A funnel shape member 5t', disposed beneath the iirebox 25, serves to direct ashes dropping from the flrebox into the ash receiver 3 l. At the same time, that portion of the member 50 which is disposed nearest the draft opening 25, serves as a baffle for causing at least a portion of the air stream iiowing through the draft intake to flow in a generally7 horizontal direction around the ash receiver to cool the lower portion of partition 24, and thus the lower part of the reservoir.
It has been found that by adjusting the width oi space 28, the equilibrium temperature of the water, when the reservoir is full, can be Varied. I have found it desirable to nx this spacing so that the equilibrium temperature will not reach the boiling point. For instance, in a range constructed in proportions shown in the drawings, I have found that the spacing between the rebox and the partition 24 may be about three-fourths inch. With this spacing, the equilibrium temperature of the water, when thevwall of the iirebox is maintained at about 800 F., will not reach the boiling point, but will be in excess of 170 F., when the reservoir is full.
1A further :objectin providing above scribed arrangement is `to reduce the ambient temperature the gas` portion 2i! oithe range. as shawn .im Fia l, thensual control knobs 1M ,areprovided` on the control panel 15 to regulate .the .eas valve. .The eas turner .arf-ansement includes ,a mixing jet ddisposed in the space 46 between the cooking top 4l Iof the gas portion nand the oyen 4,8. Air is caused to be drawn into the 4mixing "jet 45 in the usual manner, and hence the temperature of the air in the space 46 has an important bearing on the oxygen content of the combustible mixture. By disposing the reservoir 35 between the iire box and the gas portion of the range, a heat barrier is provided which maintains a lower temperature in the space 46, that is, a temperature which is less subject to the variations of the rebox temperature. In this connection it will be observed that the oven 48 of the gas portion is insulated as indicated by the reference numeral 49, thus cooperating with the reservoir 35 to maintain a substantially constant temperature in the space lili.
Of course, it will be understood that the heat tempering effect of the reservoir is equally valuable in a coal-wood and electric combination range, because in this instance it is equally important to avoid over-heating of the electrical conponents of the range, as previously pointed ou Although only a preferred embodiment of my invention has been shown and described herein, it is obvious that various modifications and changes may be made therein without departing from the spirit of my invention.
l. In a range, a casing, a water reservoir disposed in said casing and having ya wall disposed in a substantially vertical plane, a iirebox disposed in said casing alongside of the upper portion of said reservoir wall, and having a portion spaced therefrom in heat transmitting relationship with respect thereto whereby said upper wall portion constitutes a heating plate for heating water in said reservoir, a vertically disposed partition extending between said fire 'box and said reservoir and means for maintaining the lower part of said wall at a lower temperature than the temperature of said heating plate whereby the equilibrium temperature of the water in said reservoir will decrease as the water level decreases, said casing serving to confine the major portion of the heat loss from the reservoir to the heat loss taking place at the lower part of said vertical reservoir wall.
2. In a combination range, partition means providing two end compartments and a middle compartment, said compartments being arranged side by side, a water reservoir disposed in Said mlddle compartment and extending downwardly from the top surface of said range, means for burning a solid fuel in one of said end compartments, said solid fuel burning means comprising a rebox disposed in the upper part of said firstmentioned end compartment and having a wall spaced from the partition means separating said first end compartment and said middle compartment, a portion of said last-mentioned partition means being disposed in heat receiving relationship with said frebox wall, and said reservoir having a wall portion disposed adjacent the heated portion of said partition means whereby sald reservoir wall portion may be heated, said .reservoir extending below the bottom portion of said rebox to a substantial extent whereby the MICHAEL J. MAIER.
8 References Cited in the file of this paient UNITED STATES PATENTS Number Name Date Garrison Feb. 4, 1902 Lucerino Dec. 1, 1914 Teller Dec. 15, 1931 Chadwick Mar. 24, 1936 Burrow Feb. 14, 1939 Stein Dec. 17, 1940