US3011771A - Temperature controlled heater and enclosure therefor - Google Patents

Description

M. B. wLcox 3,011,771

TEMPERATURE CONTROLLED HEATER AND ENCLOSURE THEREFOR Dec. 5, 1961 2 Sheets-Sheet 1 Filed Feb. 23, 1960 INVENTOR MERR/44 B. h//Lcox lrrmvsys M. B. WILCOX Dec. 5, 1961 TEMPERATURE CONTROLLED HEATER AND ENCLOSURE THEREFOR Filed Feb. 23, 1960 2 Sheets-Sheet 2 INVENTR.

x o c m 3 I u R M United States Patent O 3,011,771 TEMPERATURE CONTROLLED HEATER AND ENCLO'SURE THEREFOR Mer-fill B. Wilcox, Minneapolis, Minn., assignor to Aladdin Manufacturing Company, Minneapolis, Minn., a

cerporation of Minnesota Filed Feb. 23, 1960, Ser. No. 10,402 8 Claims. (CI. 263-2) The invention herein presents a ther-mostatically controlled heating device and an insulated box used one inside of the other to comprise a portable heated enclosure.

In commercial practice it has become desirable to use certain liquid materials which when combined with proper catalytic agents solidify to form a relatively hard material capable of maintaining a molded shape and which are readily adaptable to usage in certain phases of public utility Operations. To function properly such liquid materials should be maintained at temperatures between 75 and 80 F., which is, for a major part of the year well above the ambient outdoor temperature in the northern parts of the nation where outdoor temperatures well below the zero degree mark are not uncommon. Further, said liquid materials are often canied in trucks or other commercial 'vehicles to the job site for use. Temperatures within such vehicles vary greatly.

Said liquid materials are often sealed in flexible, easily rupturable, heat destructable plastic containers which cannot be subjected to high, direct heat without container failure and consequent liquid loss.

The heated box is used, for example, by telephone company servicemen for keeping liquid plastic materials at a predetermined temperature so that on the job the material may be molded to form line connector blocks or similar small nonconductive parts used in the maintenance of telephone lines. The box and heater operate to keep the liquid at an even temperature so that it is instantly used whenever a part must be moldedv to complete an installation.

In a device made according to the present invention, the heat output supplied to the inside of an insulated box from a fuel burning heater located therein is regulated by thermostatically controlling the rate of air flow past the burner of said heater.

Said heater output is transmitted from said heater (l) by conduction along fins integral with and extendiug outwardly from said heater, and from said fins into and throughout an air permeable partition in contact with said fins 'and dening a heater confining area; (2) by convection due to air currents throughout the box; and (3) by radiation from said heater, fins and partition.

For use in the present invention, a catalytic type warmer i of the general type described in U.S. Letters Patent No.

2,670,728 but with an added thermostatic control has been found to be entirely satsfactory.

An object of the invention is to provide a heated, insulated box that can be readily transported by hand and placed in a truck or other commercial vehi'cle so the contents are available at the proper temperature for use on the job site during the normal work day.

In the drawings,

FIG. 1 is a top plan view of a heating device of the presentnvention showing a relative position of a thermostatic control;

FIG. 2 is a side elevational view of said heating device showing radiatng vanes and their relative spacing;

FIG. 3 is a detailed sectional view taken on the line 3-3 in FIG. 1 with parts in section and parts broken away;

FIG; 4 is a detaled sectional view taken on the line 4 t4 in FIG. 3;

FIG. 5 is a perspective view of an insul-ated, heated box of the invention showing the relative position of said heating device and of material to be kept at an even temperature;

FIG. 6 is a sectional view of said box and heating device taken on the, line. 6-6vin FIG. 5.. with the box cover in place;

FIG. 7 is a perspective View of one type of container that can be kept at a constant temperature within the insulated box; and

FIG. 8 is an enlarged fragmentary' sectional view oi a portion of the device as seen in FIG. 3. V

Refern'ng to the drawings and the numerals of reference thereon, a suitable heating device 10 comprises a fuel tank 11 filled with absorbent material 12 which is impregnated with liquid fuel, and a bu-rner unit '13 mounted on a top wall 14 of the tank 11. The burner 13 is above an opening 19 in said top wall and is spaced from and adjacent the impregnated absorbent material 12 through said opening. Said burner unit will be operative by reason of heat of combuston to cause vaporzed fuel continuously to emanate from said. absorbent material and the burner unit will utilize the fuel. which it vaporizes to. sustain combustion.

An elongated, circular wick 15 is embedded into the impregnated absorbent material and extends upwardly through the top wall 14 of the lower tank 11 to be adjacent to said burner unit. This wick. will be impregnated with liqud fuel from the absorbent material by' means of capillary -attractiom A ame applied to the wick will cause combustion to be initiated in the burner.

A cover cap 16 is removably fitted upon the upper end of fuel tank 11 and comprises a top wall 17 and spaced, side walls 20, 20 equipped with vent holes 21. Said cover cap and said lower tank each have a plurality of arallel, outwardly extending fins or vanes 18 to dissipate and radiate heat from the heater. Top wall 17 of cover cap 16 has a center hole 22, and a flue hole 23 shaped like v a segment of an annular ring concentric with and spaced from said centerhole.

A thermostatic unit 24 comprises =a bi-metallic element 25 wound as a spital which is fixedly attached at its center point to a control stud 26 and which is connected at its outermost end, to an ear 27 which ear is integral with and perpendicular to the outer periphery of a sub stantially circular damper plate 30; Said damper plate 30 hasa hole 31 at its center, and has hole 32 similar in shape and size to flue hole 23 and located in the same relation to hole 33 of said damper plate as said flue hole 23 is located in relation to center hole 22 in, top wall 17. Control stud 26 extends freely rotatably outward through said hole 31 of damper plate 30 and through center' hole 22 in said top wall 17. Damper. plate 30 is spaced slightly downward from top wall 17 and upward from the spital bi-metallic element 25, by shoulders 33 and 34 respectively on control stud 26. Said damper plate being constrained to rotate above said control stud in response to move ments of the outward end of said spital bi-metallic ele ment.

At one end of hole 32 in said damper plate is a stop ear 35 which protrudes upwardly from said' damper plate through sadflue hole 23 in the top wall 17 to limit the travel of the damper plate to, that segment of a circle described by said flue hole 23. At one limit of travel, flue hole 23 and damperhole 32 will be substantially in overlying, alined relationship,w providing a passageway for air; at the other end of travel said flue hole will be substantiaily covered by a solid portion of said damper plate. The area of fine. hole 32 which, may be uncovered between the two above described. limits. is infinitely variable.

A fiction type Washer 36 is located in surrounding relationship to said control stud 26 between the top wall 3 17 and the control knob 37 which is fixedly attached to that portion of said control stud which protrudes above said top wall, thus to insure that the control stud will be maintained in fixed angular relationshipwith respect to said cover cap as determined 'by manipulation of said manual control knob 37.

An insulated, compartmental box 41 comprises spaced, parallel side walls 42, 42 spaced, parallel end walls 43, 43, spaced, parallel bottomwall 44 and top cover 45. Said walls and the cover are made of a rigid material of relatively low heat conductivity. By way of example expanded polystyrene walls covered on the outside with a fibrous, rigid, airtight plastic skin and lined on the inside with tin foil have been found to be excellent. As shown, the top cover 45 and one end wall 43 are each provided with a pair of breather holes 46, 46. Since these breather holes 46, 46 are on faces of the box at 90 to each other, it follows that one pair will always be above the other as long as the box is positioned on a horizontal surface. The -tendency for hot air to rise inside of the box will cause an outfiow through the higher flow of breathers and a consequent inow of air through the lower thus to provide sufficient fresh air to support combustion. The size of the opening, however, is sufiiciently restricted `to have no appreciable eifect on the internal temperature of the box.

The top cover 45 is remo'vably tted at the upper edge of the 'w'alls 42, 42 and 43, 43, and is positioned between them by a shoulder 47 so that when the cover is in place, the joint between the walls and cover will be substantially airtight. The heating device previously described is positioned in one end of the box 41. A divider screen or partition 50 having relatively high heat conductivity is constructed to allow substantially unrestricted air movement therethrough, is located adjacent and contiguous to the fins 18 of said heating device li? and prevents a heat destructble plastic container 51 which encompasses the material 53 to be heated from coming in to direct contact with the fuel tank or the cover cap of the heating device. This partition 50 also serves as a means for further dissipating heat from the burner to the atmosphere within the box. A thermometer 52. is located in the top cover 41 to indicate the arnbient temperature within the box. v

FIG. 7 llustrates one type of container for storing liquid material for which this box and hcater unit was designed. The disclosure comprises the sealed, flexible, heat destructible plastic contaner 51, substantially filled with liquid 53 which must be at a temperature of between 75 and 80' F. at the time t is used. When this liquid is poured into a mold or other form and suitable Catalyst added, it solidifies into the shape defined by said mold and is then suitable to' perform its ultimate intended use.

The heating device 10 can be removed from the box so that a volatile liquid fuel can be poured into the lower tank 11 and the wick will then be ignited by placing a ame to it with the cover cap removed. As explained above, the liquid fuel will be drawn upwardly through the wick so that the wick will continue to flame. After the burner has been sufliciently heated by the wick to support and sustain combustion, the cover cap will be replaced, thus extinguishing the wick. The control knob 37 will then be adjusted so the pointer 38 is set to the desired heat level as shown by indicia 40 on said cover cap top wall 17. The flue hole 23 through the top wall of the cover cap and hole 32 through the damper plate will be substantially coincident and alined when the unit is cold and is first ignited.

Heat emanating from the burner will set up a convection current by taking in cool air through the side holes 21, which are below the burner and discharging heated air, which tends to rise, through the passageway provided by hole 32 and fiue hole 23 in the damper plate and top wall of the cover cap respectively.

The cover cap and lower tank will conduct heat away from the burner to the parallel vanes 18. Sad vanes are of relatively greater area and will rapidly radiate the heat to the surrounding atmosphere and to passing convecton air Currents.

As combustion continues the ambient temperature within the cover cap will rise, causing the spiral bimetallic strip to expand. This will cause its constrained outward end, which is fastened to ear 27 to move in a substantially circular motion and in turn cause the damper plate 36 to rotate about the control stud 26. As the damper plate rotates, flue hole 23 and damper hole 32 no longer coincide and ilue hole 23 becomes partially covered by a solid portion of the damper plate. This restricts the convection flow of air across the burner, slows the rate of combustion, and reduces the amount of heat produced or generated by the burner.

'Ihe transfer of heat through the integral vanes to the surrounding air continues and the ambient temperature at the thermostatic unit is reduced. This causes the spral bi-metallic strip to contract, uncovering a greater portion of the flue hole 23 and again increasing the rate of' combustion. This action occurs during minute differentials of temperature so that substantially a uniform amount of heat is produced or generated by the burner at any particular setting of the control knob.

It should be noted that vent holes 21 are of such size and arrangement so .they allow sufiicient exchange of air to support burner combustion at a reduced rate and so that at no time will the burner become extinguished due to lack of oxygen, even if the fiue hole 23 is fully covered by damper plate 24.

With the heating device 10 in the insulated box 41 so that the screen divider or partition is in contact with the fins and is separating the heater, and with the cover 45 in place, heat from the vanes 18 will be radiated to the surrounding air and will be conducted to the partition 50 and throughout that partition. The air inside of the box will circulate from normal convcction currents, illustrated generally by the arrows 54 in FIG. 6, thereby maintaining a substantially uniforrn temperature throughout the interier of the box 41.

What is claimed is:

1. A temperature controlled heater including a fuel tank having an opening in a top end thereof, liquid fuel impregnatable absorbent materials substantially filling said tank, a burner to burn fuel vapors from said tank opening Situated in spaced, overlyingvrelation to said tank opening, a cover mountcd on said tank and encompassing said burner, said cover being provided with air entrance and combustion product egress openings, a damper plate pivotally mounted with respect to said cover and having a damper opening therethrough, an ear fixedly attached to said damper plate and projecting through said egress opening, said damper plate being moveable between a first position in which said damper opening and said egress opening are in alined relationship to each other and a second position in' which said damper plate substantially blocks said egress opening, and means operative to move said damper plate between said first and said second position responsive to the temperature of said heater.

2. The combinaton as specified in claim 1, a portable insulated box enclosing said heater, and means within said box constituted as an air permeable partition providing within said box a heater conning area and a temperature controlled storage area;

3. The combination as specified in claim l wherein said means for controlling said damper includes a stud manually rotatable with respect to said cover, and a bi-metallic element mounted at a first end thereof to said stud, said damper being rotatably m'ounted With respect to said stud and fastened to a second end of said bi-metallic ele ment. a

4. A temperature controlled heater including a fuel tank having an opening in a top end thereof, liquid fuel impregnatable absorbent materials substantially filling said tank, a burner to burn fuel vapors from said tank opening Situated in spaced, overlying relationship to said tank opening, a cover having side Walls mounted on said tank and a top wall, said cover encompassing saidburner, at least one of said side walls having an air accew opening therethrough and said top wall having an egress opening therethrough; a damper plate mounted with respect to said cover and having a damper opening therethrough, said damper plate being movable between first position in which said damper opening and said egress opening are in alined relationship with each other to permit unobstructed passage of the products of combustion from said burner to outside of said heater and a second position in which said damper plate prevents substantial flow of said combustion products through said egress opening, temperature controlled means operative to move said damper plate between said first and second positions, a plurality of beat conduction fins integral with and extending outwardly from said heater, a portable insulated box enclosing said heater, and means within said box constituted as an air permeable partition of relatively high heat conductivity providing within said box a heater confining area and a temperature controlled storage area, said partition being in Contacting, heat conducting relationship to at least some of said fins.

5. The combination as specified in claim 4, wherein said box is provided with at least two breather holes open from outside said box to inside thereof, said holes being Situated to normally lie in spaced, vertical relationship with respect to each other.

6. A temperature controlled heater including a fuel tank having an opening in a top end thereof, liquid fuel impregnatable absorbent material substantially filling said tank, -a burner to burn fuel vapors from said tank opening situated in spaced, overlying relationship to said tank opening, a cover having side walls mounted on said tank and a top wall, said cover encompassing said burner, at least one of said side walls having an air access opening therethrough and said top wall having an egress opening therethrough, a damper plate mounted with respect to said cover and having a damper opening therethrough, said damper plate being movable between a first position in which said damper opening and said egress opening are in aligned relationship with each other to permit unobstructed passage of the products of combustion from said burner to outside of said heater and a second position in which said damper plate prevents substantial flow of said combustion products through said egress opening, a control stud frictionally rotatably mounted through said top wall of said cover, a spiral Wound bi-rnetallic ele ment fixedly mounted at an inner end thereof to said stud, and a manual control knob integral with said control stud outside of said cover, said damper plate being freely rotatably mounted on said stud and fastened to an outer end of said bi-metallic element.

7. The combination as specified in claim 6, and a plurality of heat conducting ns integral with and extending outwardly from said heater.

8. The combination as specified in claim 6, a potable nsulated box enclosing said heater, means within said box constituted as an air permeable partiton of relatively high heat conductivity providing within said box a heater confining area and a temperature controlled storage area, said partition being in Contacting, heat conducting relationship to said heater, and wherein said box is provided with at least two breather holes open from outside said box to inside thereof, said holes being Situated to normally lie in spaced vertical relationship with respect to each other.

References Cited in the file of this patent UNITED STATES PATENTS 273,757 Morel Mar. 13, 1833 945302 Brown Jan. 4, 1910 1,659,875 Jacobs Feb. 21, 1928 2,458,837 Dougherty Jan. 11, 1949 2,670,728 Smith Mar. 2, 1954 2,780,28O Allen Feb. 5, 1957

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