US3007256A - Heating and drying apparatus and method - Google Patents

Description

Nov. 7, 1961 A. L. M. A. ROUY 3,007,256

HEATING AND DRYING APPARATUS AND METHOD Filed Sept. 12, 1957 3 Sheets-Sheet l o o o o o o o b o o o o o o Z2 Z2 0 o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o 0 Q FIG. I

V INVENTOR. Z Z Auguste L.M.A.Rouy

' O Y I ATTORNEY MDWLOUQWO O Q 7070. EL.

A. M. A. ROUY 3,007,256

HEATING AND DRYING APPARATUS AND METHOD 3 Sheets-Sheet 2 Nov. 7, 1961 Filed Sept. 12, 1957 FIG. 2

22 f l I'" I! Z; i/ 35 z 45 T t g" 4 21 Z0 I if? o 4 5a Z5 Z4 ;-I Z5 40 if 37 Z94 27 2; 2a 59 FIG. 5

INVENTOR. Auguste L.M. A. Rouy ATTORNEY Nov. 7, 1961 A. L. M. A. ROUY HEATING AND DRYING APPARATUS AND METHOD Filed Sept. 12, 1957 3 Sheets-Sheet 3 FIG. 7

RINSE TEMPERATURE FIG.8

INVENTOR. Auguste L.M.A.Rouy BY/% 10mm I nited tates The present invention relates to an apparatus for heating and drying articles, and refers more particularly to a method of drying articles by electrically heated air, and to apparatus for carrying out the method.

An object of the present invention is the provision of methods and apparatus for heating and drying of articles, which is particularly safe in operation and thus suited to use in the household and by relatively unskilled operators generally.

A further object is the provision of apparatus for the method, which is compact, has relatively few parts, and is economically manufactured from standard components and by well known techniques.

More particularly, an object is to provide a low temperature stove and oven, suitable for pasteurizing foods, maintaining solutions or other materials at a fixed low heat temperature, and for warming household dishes, chinaware, etc. preparatory to placing food therein.

Another particular object is the provision of an efficient, rapid and safe dish drier for household kitchen use and the like.

In accomplishing the objects of the present invention, the articles to be heated or dried are placed in a relatively slowly ascending, homogeneous column of moderately hot air, of the order of 100 F. above room temperature, and are thus brought to a temperature of 170 F.l 80 F. Such temperature, plus the continuous passage of the hot air, soon affects the drying of the articles if the same were wet.

The principal instrumentality for the practice of the method is a low temperature, hot air stove, furnishing the homogeneous column of slowly ascending hot air. Said stove comprises a relatively shallow pan, a blower having an electric heater and supplying hot air to the interior of the pan, and a cover fitting the top of the pan and formed with a multiplicity of evenly distributed perforations through which the hot air escapes to form the slowly ascending, homogeneous column of hot air.

Theblower is detachably mounted on the pan for quick assembly in manufacture andto facilitate cleaning of the pan and storage of the blower therein when the device is not in use.

Enclosing means are advantageously provided, surrounding the hot air-column and resting on the cover of the pan, and preventing dilution of the'hot air column by the cooler air surrounding the apparatus. Vented cover means are also provided for the enclosure means, for those occasions when the device is to be used to maintain the heated articles at elevated temperature for a period of time.

When wet articles are to be dried, drainage means are further provided, comprising means providing an inclined position of the-cover ofthe pan, and raised flanges surrounding each perforation of the cover of the pan, whereby liquid draining from the articles to the cover of the pan is led away by gravity and excluded from entering the pan by way of the said perforations of the cover of the pan. Means are further provided causing the pan to adjustably assume a position in which the cover thereof is level, when the purpose is merely to heat the articles placed thereon.

Alternative means are provided for excluding the draining water from the perforations, constituted of forming 3,007,256 Patented Nov. 7, 1961 ice the perforations in a vertical, downhill facing plane and elevated from the plane of the cover.

The enclosing means for the ascending hot air column is further made collapsible, and when collapsed said means fits within its cover, which is hollow, for convenience in transportation and in storage.

Alternative stove means are further provided, comprising the hot air blower and distributing means for the hot air comprising an intermediate conduit and a plurality of pipes leading from the conduit and formed with perforations.

The invention accordingly consists in the features of construction, combinations of elements and arrangements of parts which Willbe exemplified in the constructions and methods hereinafter described. In the accompanying drawing, in which are shown three of the various possible illustrative embodiments of this invention:

FIGURE 1 is a top plan view of the novel low heat stove of the present invention.

FIGURE 2 is a section on the line 22 of FIGURE 1, further showing a rack of dishes placed on the stove for drying.

FIGURE 3 is a side elevation of the hot air blower and its flange for detachable mounting on the stove.

FIGURE 4 is an end elevation of the same.

FIGURE 5 is an enlarged fragment of FIGURE 2.

FIGURE 6 is an enlarged fragmentary end view of the pan cover.

FIGURE 7 is a chart showing drying time of household dishes in minutes for various temperatures of rinse water and various wattages of heating element in the hot air blower.

FIGURE 8 is a side elevation of the stove, showing the same applied to the drying of a wet textile article hung thereabove.

FIGURE 9 is a side elevation of the stove further showing, partially in fragment, a side wall member and cover therefor converting the stove to a low temperature oven.

FIGURE 10 is a perspective view of the side wall member, showing the same partially collapsed.

FIGURE 11 is a plan view of a modified form of the low heat stove.

FIGURE 12 is a fragmentary plan view of a modified form of top wall for a low heat stove.

FIGURE 13 is a section on the line 1313 of FIG- URE 12.

FIGURE 14 is a section on the line 14-14 of FIG- URE 12.

Referring now in detail to the drawing, a low heat stove 19 is constituted of the pan 20,.cover 21 and blower 32 to be described hereafter. The pan and cover together constitute a relatively shallow housing. The relatively shallow pan 20 is of generally rectangular plan outline, as seen from FIGURES 1 and 2 viewed together, FIGUREl showing the cover 21 of pan 20, and FIG- URE 2 showing that cover 21 has the flange portion 22 of substantially semi-circular cross section extending entirely around the periphery thereof and engaging the complementary flange portion 23 extending entirely around the periphery of pan 20. Pan 20 is somewhat longer than broad, and has a higher left end wall 24 as viewed in the figures, a lower right end wall 25, and downwardly and rightwardly diminishing side walls 26. By reason of such construction the peripheral flanges 2.2, 23 are normally supported in a plane inclined to horizontal and lower on the right end as viewed. As the flanges 22, 23 constitute interengaging means supporting cover 21, said cover is also normally, as in FIGURES 1, 2 and 8, supported in a plane inclined to horizontal and lower on the right end as viewed.

The pan 20 is an aluminum sheet metal stamping product. It has a small drainage hole 27 substantially in the center of its bottom wall 28, and three such holes 29 at the right end of bottom wall 28, one substantially central of the width and one approximately at each corner, and all substantially at the bottom of the low right end wall 25.

Feet 28A formed in the stamping operation raise the bottom wall 28 above a supporting surface on which the pan 20 may be placed. An insulating board 29A of asbestos or the like is advantageously placed over bottom wall 28, covering the same and resting thereon.

A mounting collar 30 is located centrally of the high end wall 24 surrounding a through hole in the latter, collar 30 being formed with three equally spaced L shaped slots 31. A hot air blower 32 is encased in the housing 33 having the pins 34 engaging the slots 31, the blower thereby being detachably mounted in the pan. Blower 32 is conventional and includes the axial flow fan 35 mounted on the shaft of electric motor 36. Also enclosed in housing 33 is the electric heating coil 37 supported on the ceramic core 38. A heavy wire grid 39 is placed in the intake port 40 of the blower.

Cover 21 is substantially flat and rectangular, measuring 14 by 16 inches approximately in one operative embodiment, and is formed with 154 evenly distributed perforations 41 extending in the form. of a square grid the perforations being round holes of three sixteenths of an inch diameter, one and one-eighth inches between centers in each direction, and approximately the same distance from the edge of the cover. The area of the perforations 41 therefore amounts to approximately two percent of the total plan area of the cover 21.

Surrounding each perforation 41 is the upwarding extending flange 42. The flanges 22, 23 are downwardly indented midway of low end wall 25, forming a drainage channel 43 in flange 22. Adjacent each corner, cover 21 further has the depressions 44.

A wire basket 45 having feet 46 resting in the depressions 44 may be used to support household dishes 47, glasses 48 and the like in substantially vertical position above cover 21 when the articles are to be dried after washing.

The method of operation of the invention is as follows, when applied to the drying of wet articles. The hot air blower 32 being energized, the fan 35 will draw air through port 40 and force the same through the motor 36 and over the heating coil 37 which, as is well known, is maintained at about 1200 F. in operation. The air is thus both sterilized and heated, and passes out the delivery orifice 49 of blower 32 and into the pan 20, all as indicated by the arrows in FIGURE 2. The air then passes with equal pressure out of each of the orifices 41, and then proceeds as a substantially homogeneous column to rise upwardly at reduced velocity, heating the basket 45, dishes 47, glasses 48 etc., and evaporating from the articles such water as has not already drained therefrom. The air velocity as determined initially by fan 35 has a relation to the heating coil 37 such as to produce a 120 F. rise in temperature of the air leaving orifice 49, and the loss of heat to pan 20' and cover 21, amounts to approximately 20 F. at equilibrium, so that the air column rising from cover 21 is no more than 100 F. above room temperature, and the apparatus and its contents will therefore not rise above 170 F. to 180 F. Such temperature will not produce skin burn and the apparatus and method is therefore well suited to household use and to operation by users without particular training.

Water dripping from the articles 47, 48 falls to cover 21 and is drained away by gravity, cover 21 sloping downwardly from left to right as viewed, and the water finally draining through the channel 43 into a sink or other preferred catch means. The upwardly extending flanges 42 surrounding the perforations 41 prevent the draining Water from entering the pan 20 by way of said perforations.

Heat loss through the bottom wall 28 is minimized by the feet 28A which by raising the pan 20 provide air insulation thereunder. The insulating board 29A is a further means preventing downward loss of heat.

The drying times for a basket full of dishes have been observed in connection with a pan 20 approximately 16 x 13 inches, the basket 35 holding enough dishes for a family of six persons. The observations were made of blowers delivering 20 c.f.m. of air over heating coils of 500, 750 and 1000 watt respective ratings, and the dishes having been rinsed in water varying from 70 F. to F. It will be seen from the solid line curves in FIG- URE 7 that with the 7 50 watt coil and 70 F. rinse water, the dishes were completely dry in 10 minutes, while with 125 F. rinse water the dishes were dry in less than 6 minutes.

Referring now to FIGURE 8, it will be seen that the stove 19 comprising the pan 20, cover 21 and blower 32, is useful in the hot air drying of various articles such as the towel 50 suspended from the peg rack 51. The stove 19 is in fact useful in all heating and drying operations in which the object is either rested directly on cover 21 of stove 19 or supported thereabove by air pervious means.

The velocity of air escaping each perforation 41 is 15 f.p.s. while the average velocity of the homogeneous column of air is 2 to 3 fps, the rising of the air of the column being mostly due to its lesser specific gravity due to its elevated temperature.

When the stove 19 is to be used for heating objects which it is desirable to support in an upright rather than an inclined position, such as a pot 52 of liquid, or a stack of household dishes to be warmed, the cover 21 may be supported in horizontal position by means of the two legs 53 mounted on pivot pins 54 adjacent the low right end wall 25 on each side wall 26, and underlying the low portion of the top peripheral flange 23. Said legs 53 have an inoperative, horizontal position illustrated in FIGURE 8 and in broken lines in FIGURES 2 and 9. Legs 53 may be swung to the operative position illustrated in full lines in FIGURE 9. The limit of swinging motion is determined by the stop pins 55. In the operative, substantially vertical position of legs 53, the position of pan 20 is changed relative to a supporting surface 56, raising the low lying portion of peripheral flange 23 so that the flange is now substantially horizontal, thus supporting cover 21 in horizontal position, and maintaining upright articles placed thereon, as illustrated in FIGURE 9.

FIGURE 9 further illustrates novel means combining with stove 19 to constitute an oven. The side wall member 57 rests on cover 21, extending around the periphery thereof and thereby enclosing on all four sides the ascending column of hot air. Member 57 comprises six separate sheets of metal each joined to the next by a pair of hinges 58 so that the member is collapsible. In FIG- URE 10 member 57 is shown partially collapsed. When fully collapsed the member is substantially flat and fits within the hollow cover 59 which is formed with several air vents 60 and a hinged, collapsing handle 61.

When used to warm dishes, the oven 62 thus constituted enjoys the advantage that the dishes do not become too hot to handle, due to the maximum operating temperature of F. to F. at ordinary room temperature. Said temperature is also quite useful in the pasteurizing of foods.

Referring once more to FIGURE 7, the broken line curve discloses that with the use of the side wall member 57 together with basket 45, a full load of dishes to be dried in the basket, using a 750 watt heating element 37 in blower 32, will dry in less than six minutes with 70 F. rinse water, and in less than three minutes with 125 F. rinse water. Such diminution of drying time is due to the fact that side wall member 57 prevents the induced mixture of cold outside air with the homogeneous hot air column rising from stove 19.

In FIGURE 11 is illustrated a low temperature hot air stove 70 compirpsing the hot air blower 71 supplying hot air to the intermediate conduit 72 which is preferably a sheet metal tube of square cross section. On the side of conduit 72 opposite blower 71 are the four pipe flanges 73 and in each flange 73 is threaded a pipe 74, the outer ends of pipes 74 being closed in any desired manner. The pipes 74 are formed with the evenly spaced perforations 75, and means is thus provided furnishing the slowly ascending homogeneous column of hot air, similar in operation to stove 19.

In FIGURE 12 is illustrated a fragment of a substantially flat top wall 80 of a housing of a hot air stove similar in all respects to stove 19 except as noted hereafter. As in stove 19, the top wall of the housing may be immovable relative to the housing or may be a separate removable cover similar to cover 21. The top wall 80 slants downwardly from left to right and is formed with the approximately hemispherical raised portions 81, each portion 81 having a higher half portion 82 and a lower half portion 83. The raised portions 8 1, as well as their half portions 82, 83 are thus all sedments of spheres. The perforations 84 are located between the half portions 82, 83, facing downhill or in the direction of the downward slant of the wall 80. When a stove comprising such a top wall 80 is used to dry wet articles placed thereabove, drops of water falling anywhere on the top wall 80 are effectively drained away, it being virtually impossible for the draining drops to enter the downhill facing perforations 84.

It will thus be seen that there is provided a device and method in which the several objects of this invention are achieved, and which is well adapted to meet the conditions of practical use. As various possible embodiments might be made of the above invention, and as various changes might be made in the embodiments above set forth, it is to be understood that all matter herein set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a dish dryer for drying wet dishes, or the like, comprising a relatively shallow pan having a substantially flat top wall inclined from horizontal, the said top wall being formed substantially throughout its area with a multiplicity of substantially evenly-spaced perforations, a blower supplying air to the interior of the pan and maintaining the pressure of air therewithin above normal atmospheric pressure, means heating the air supplied by the blower to the interior of the pan, the heated air in the pan escaping from the perforations in the top wall and merging into a substantially homogeneous slowly ascending air column, and drainage means asosciated with each perforation for preventing the entrance of liquid on the top wall into the said pan, said drainage means comprising integral, offset portions of the top wall extending upwardly therefrom.

'2. The invention as recited in claim 1, wherein the said drainage means includes a raised flange substantially surrounding each perforation.

References Cited in the file of this patent UNITED STATES PATENTS 45,471 Buell et al. Dec. 20, 1864 807,408 Wegner Dec. 12, 1905 1,658,489 Lindstrom Feb. 7, 1928 2,188,880 Lewis et al. Jan. 30, 1940 2,197,178 Gates Apr. 16, 1940 2,267,158 Locke Dec. 23, 1941 2,416,165 Evans Feb. 18, 1947 2,668,368 Jacobs Feb. 9, 1954 2,707,838 Braman May 10, 1955 2,758,387 Stann Aug. 14, 1956 2,884,708 Levitt May 5, 1959 FOREIGN PATENTS 929,183 France Dec. 18, 1947

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