US2981819A

US2981819A - Heater construction for kiln or other apparatus

Info

Publication number: US2981819A
Authority: US
Publication date: 1961-04-25
Anticipated expiration: 1978-04-25

Description

, 19 1 J. J. GREGORY April 25 HEATER CONSTRUCTION FOR KILN OR OTHER APPARATUS Filed OCT,- 25, 1957 5 Sheets-Sheet 1 4 INVENTOR.

JAMES J. GREGORY BY Qa, W 4, Z A M A ril 25, 1961 J. J. GREGORY 2,981,819

HEATER CONSTRUCTION FOR KILN OR OTHER APPARATUS Filed Oct. 23, 1957 5 Sheets-Sheet 2 INVENTOR. i n a JAMES :J. GE'GOflf ATTORNEYS April 25, 1961 J. J. GREGORY 2,981,819

HEATER CONSTRUCTION FOR KILN OR OTHER APPARATUS Filed Oct. 25, 1957 5 Sheets-Sheet 4 INVENTOR. JAMES J. GREGORY A Tl'OE/VEYS United States Patent HEATER CONSTRUCTION FOR KILN OR OTHER APPARATUS James J. Gregory, 21570 Edgeclitf Blvd, Euclid 23, Ohio Filed Oct. 23, 1957, Ser. No. 691,991 16 Claims. (Cl. 219-35) This invention relates to a heater construction and more particularly to a portable kiln usable for heating enamels, ceramics, metals, and other objects or articles.

An object of the present invention is to provide a kiln or other type heating construction especially adapted for heating ceramic, enamel, clay, porcelain, frits and glazes; adapted to be used in the ceramic field, of light weight; having a short heat-up period; requiring no gloves for loading or unloading, having a low heat reservoir; having components protected against burn-out; having no harmful ultra-violet rays; inexpensive to operate; safe to operate under all working conditions; adapted to be used for its intended purpose with a construction having a minimum of insulation and a minimum of basic framework; and adapted to be used for enameling, glazing, porcelainizing, or brazing localized areas on large objects.

A further object of the present invention is to provide a heater construction or kiln characterized by its structural simplicity, economy of manufacture, ease of assembly of its component parts, strong and sturdy nature, and operating eificiency.

Other features of this invention reside in the arrangement and design of the parts for carrying out their appropriate functions.

Other objects and advantages of this invention will be apparent from the accompanying drawings and description and the essential features will be set forth in the appended claims.

In the drawings,

Fig. 1 is a front elevational view of a kiln portraying the present invention;

Fig. 2 is a side elevational View, partially in section, looking toward the right at the left-hand side of the kiln in Fig. 1;

Fig. 3 is a vertical sectional view taken along the line 3-3 of Fig. 2 through the kiln;

Fig. 4 is a vertical sectional view taken along the line 44 of Fig. 1;

Fig. 5 is a top plan view, partially in section and taken generally along the line 55 of Fig. 4, of the kiln with the coolinghood removed;

Fig. 6 is an electrical diagram of the radiant heating lamps and air blower fan; while Fig. 7 is an enlarged sectional view of a portion of the reflector in Fig. 3."

Before the construction here illustrated is specifically described, it is to be understood that the invention here involved is not limited to the structural details or arrangement'of parts here shown since constructions embodying the present invention may take various forms. It also is to be understood that the phraseology or terminology herein employed is for purposes of description and not of limitation since the scope of the present invention is denotedv by the appended claims.

While the present invention might be adapted to various types of uses, I have chosen to show the same as ap-.

plied to a kiln for heating objects and/ or fusingceramic,

'ice

enamel, clay, porcelain, frits and glazes. It should also be apparent that all or portions of the heater construc tion disclosed hereinafter may be used for cooking foods, for fast thawing frozen ore cars prior to dumping, for heating conveyed materials, for heating containers of materials, etc.

The kiln or furnace herein may be constructed of any conventional materials but is disclosed specifically herein as constructed of suitable refractory materials supported by a metal superstructure described hereinafter as a base housing 10.

Base housing 10 has four

parallel corner members

11, 12, 13 and 14, each L-shaped in cross section, located at respective corners of a rectangle, as shown in Fig. 5. These corner members have respective

corresponding flanges

11a, 11b, 12a,

12b

13a, 13b, 14a and 14b. Adjacent flanges are mutually coplanar, for example,

flanges

11a and 12b are coplanar in Fig. 5, to form a channel 16 rectangular in cross section, as shown in Fig. 5. This channel 16, rectangular in cross section, has an upper open end 16a and an at least partially closed lower end 16b, as shown in Figs. 3 and 4.

Base housing 10 has four connecting

members

21, 22, 23, and 24, each L-shaped in cross section, secured at opposite ends respectively to adjacent corner members.

For example, connecting member 21 is shown being secured at opposite ends to

flanges

11a and 12b of corner members 11 and 12. This securement can be by any suitable type connecting means but is shown herein as a welded connection between the component members. Each connecting member is L-shaped in section with a bottom flange designated by the reference numeral a and with the side flange designated by the reference numeral b, such as connecting member 24 in Fig. 3 having bottom flange 24a and side flange 24b.

Side flanges

21b, 22b, 23b and 24b form the sides of the rectangular channel 16;

bottom flanges 21a

22a, 23a, and 24a are coplanar and form the border closed bottom end 1611 of the channel 16. Here the upper ends of the

corner members

11, 12, 13 and 14, remote from closed end 16b, form the open end 16a of the channel. Each

corner member

11, 12, 13 and 14 has a portion thereof extending down below the plane, formed by flanges 21a24a, to form supporting legs 11 12 13 and 141 for the kiln.

Base housing 14) has a front side 18a in Fig. l, bordered by

members

11, 12 and 21, forming one side of the rectangular channel 16 and forming the front side of the kiln.

On front side 10a, lower and

upper channel members

27 and 28, each U-shape in cross section in Figs. 2 and 4, are connected in parallel relationship with their channel openings facing each other by being welded or otherwise secured at opposite ends to the corner members 11 and 12 forming the opposite edges of the front side 10a. Two

doors

29, 29 are slidably connected in the U-shaped channels of

members

27 and 23 and are adapted to be moved by handles 30 secured thereto between the kiln closed position in Fig. 1 with these doors 29 in abutting relationship and a kiln open position with the doors in spaced apart relationship to permit loading of the kiln with objects to be heated.

This base housing 10 may also include extra plates for support such as bottom plate 32 in Figs. 3 and 4 closing channel end 16b resting upon the coplanar flanges 21a24a and a back plate 34 resingagainst the generally

coplanar flanges

13a, 14b and 23b.

An assembled unit 36 is adapted to be mounted within the base housing 10. This assembled unit 36 has interconnected walls including a back wall 38, a bottom wall 39, a top wall 40, a front wall 41 and

opposite side walls

45 and 4 6 forming heating zone or enclosed heating chamber 47 therebetween. Front'wall 41 includes top connecting means or top beam 42 and doors 29. Top connecting means 42 forms with bottom wall 39 and

opposite walls

45 and 46 an open front for chamber 47 for kiln loading with this open front adapted to be closed by doors 29. The

opposite side walls

45 and 46 include respectively

base portions

45a and 46a having recesses formed in their top and outer surfaces, connecting bars 45b and 461) secured at opposite ends to the

bases

45a and 46a, and

channels

450 and 46c between the respective connecting bars and bases. A suitable heat source 49 is located within the heating chamber 47 to provide the heat desired therein. Bottom wall 39, back wall 38, front wall top beam 42, opposite

side wall bases

45a and 46a, and opposite side wall bars 45b and 4612 are shown herein as formed of refractory material, such as fire bricks, but may be formed of any other suitable heat resistant material of low heat conductivity, such as any suitable ceramics. These last-mentioned walls, bases, bars and connecting beam are suitably cemented together in the assembled form to form assembled unit 36 and the enclosing heating chamber 47.

Top wall 40, extending across the rectangular channel 16 and located closest the channel open end 16a, is a suitably curved reflector. This reflector may be of any suitable type and shape and is adapted to coact with a heat source 49 comprising one or more infra-red lamps 50. The reflector 40' may include a single downwardly concave curve with a single heat lamp 59 located within the curve or a plurality of lamps 59, shown as four in number in Fig. 4. The reflector 40 may have a plurality of downwardly facing concave curves laterally spaced apart, either separate or interconnected, instead of the single concave curve shown in Fig. 4. Each concave curve of this multiple curve reflector may have a single or a plurality of heat lamps 54 within the curve. The concave curve of the single type or each concave curve of the multiple type may be parabolic, eliptical, hyperbolic, dish-shaped or any combination thereof. However, the choice of reflector curve; the number of concave curves in the reflector; and the relative location between the focus of the curves, the lamps and the top of bottom wall 39 must be chosen to give the desired heat concentration on the object to be placed on wall 39 and in the preferred location on wall 39.

The reflector 49 may be formed of any suitable material, but is preferably formed of heat conductive material for reasons to be more apparent hereinafter. it may be formed of metallic or non-metallic composition provided it has proper emissivity or reflective characteristics. The reflector of proper curvature can be formed over patterns cast or machined. Its reflecting surface may be coated with a high reflective, low oxidation potential ma terial, such as gold, platinum, etc., using the vapor deposition, electrolytic or any other method suitable for the application of the coating. One suitable reflector, and the form preferred in the present construction, is a metallic Alzak reflector of the conventional type wherein a sheet of aluminum has its reflecting sides 4hr in Figs. 3, 4 and 7 processed as follows. First, an electrolytic brightening treatment is applied to uniformly remove a very thin layer of metal from the surface and any foreign material which may have become imbedded in the surface during fabrication of the reflector. maximum reflection. Second, this clean aluminum surface is then protected by an electrolyticanodic oxide coating to provide a glass-like, transparent, weather resistant and cleanable surface showing the bright, underlying metal as a reflector. The resulting construction is shown in Fig. 7 wherein the reflector 40 has an aluminum base 49a with an oxide coating 40b on the reflecting side 40r thereof so that the reflector has high reflectivity with this oxide coating 4012 having a higher meltingpoint than the aluminum base fla.

The radiant energy, infra-red, heat source 49 may be of any suitable type for creating the desired high opera ing temperature in the enclosed heating chamber 47 but is preferably one or more electric, infra-red, radiant energy lamps 54), four being shown in the present disclosure. Each is mounted in the

opposite side walls

45 and 46 in the heating chamber 57 in spaced relationsihp to the reflector 40 on the reflecting side 40; thereof for emitting radiant energy against tthis reflecting side 40r over the reflecting surface area bounded by back wall 38, front top beam 42, and

opposite side walls

45 and 46 so as to obtain a heat concentration on a plane or irregular surface slightly above the bottom wall 39 upon which the object to be heated will rest for fusing porcelain, enamels, and glazes thereto or fusing fire clays or ceramics. Lamps 50 may be of any suitable type, but each is preferably of the type disclosed in the United States Patent entitled Electric Radiant Energy Device patented by A. G. Foote on February 15, 1954 as Patent No. 2,342,044. This type lamp has a quartz, or other suitable vitreous material, envelope 5nd having opposite ends, being tubular in form and having a longitudinal central axis Sflf. This lamp has a suitable means 5nd, as disclosed in said patent, for transforming electrical energy into radiant energy, which means extends through envelope Sfla along axis 50f and is operatively connected to the two electrically conductive terminals 501) and 500 operatively secured to the opposite ends of envelope Sfla along the source axis 50f. Each lamp 5%) may have either a clear or opaque vitreous envelope 56m and may be usable on any suitable voltage or phase circuit. If desired, a rheostat, either manually or thermostatically controlled or a combination thereof, can be applied in the energizing circuit of these lamps 50 in Fig. 6 so that the deisred temperature will be maintained in the enclosed heating chambers 47.

The terminals 50]; and 59c are supplied by electric power through suitable leads 51 and 52 in Figs. 3, 5 and 6 from a common electrical power source. The leads to these respective terminals Stib and 590 include respectively bus bars 51:: and 52a, secured in appropriate grooves formed in the top of the

opposite side walls

45 and 46 and connected to the electric source by power lines and 56, and include branch wires 51b and 521) secured at one end by connecting

screws

51c and 52c to the bus bars 51a and 52a and at the other end by

connections

53 and 54 to the associated lamp terminals 56b and 500.

The aforesaid patented infra-red, radiant energy heat lamps 59 are especially well adapted for the purpose described and illustrated because they come up to full temerature ahnost instantly, when energized to a heat emitting relationship, for creating the high operating temperature desired Within the heating chamber 47 but still lose about 80% of their radiant energy within a few seconds after turn-off. Also, the quartz envelopes 50a resist high temperatures so that the enclosed heating chamber 47 may become very hot without damaginglamps 56. For example, quartz softens at 3000 degrees Fahreinheit in contrast with the ordinary light bulb glass softening at 840 degrees Fahreniheit.

Suitable structure is provided for mounting reflector 4t) and lamps Sit in the

opposite side walls

45 and 46 for con- This develops venient assembly and to provide a multiplicity of advantages. These opposite side walls 45 and 46- have extending through their faces coaxially aligned

bores

45m and 46m respectively for mounting each lamp 50 in spaced relationship to the reflecting side 40r of reflector 4t) and within the enclosed heating chamber 47 but with each lamp 5t protruding through the

opposite side walls

45 and 46 in the manner shown in Figs. 3 and Sso that both terminals 50b and 500 thereof, leads 51 and 52, and connections 53 and54 are located outside the opposite side walls 45 and 4-6 from the heating chamber 47.

Suitable sleeves

57 and 58 surround each lamp tubular envelope 50a in the aligned bores 45m and 46m for mounting the lamp 50 therein and preventing escape of the heat from within the heating chamber47f These sleeves may be formed of suitable asbestos, fire brick, or ceramic type cement material forced within the bores around the tubular lamps to mount the longitudinal central axis 50 of each lamp 50 coaxial with the aligned bores 45m and 46m.

Reflector 40 has its opposite ends mounted in straight groves 38n in back wall 38 and groove 42m in the front top connecting beam 42, and has its sides mounted in the arcuate grooves 45n and 4611 of the

side walls

45 and 46. It should be noted that the reflector 40 is shaped in a curve with the elements of the curve, shown as straight horizontal lines in Fig. 3, extending parallel to an axis or axes coinciding with or extending parallel to the longitudinal axes 50 of the lamps 50 so as to be symmetrical therewith. These aligned grooves 45:1 and 4611, formed on the inner surfaces of the

side walls

45 and 46, also have their elements coinciding with the elements of reflector 40 and extending parallel to the axes of the aforesaid aligned bores 45m and 46m and to the longitudinal axes 519]. The grooves are curved in a plane transverse to the axis of the bores and along the same curve as the reflector 49. Hence, assembly of the unit 36 is easily achieved by moving the

opposite side walls

45 and 46 toward each other by approach movement along the axes of

bores

45m and 46m, while reflector 40 and lamps 50 are properly located in their respective groves and bores, and are disassembledby separation movement of these side walls. This is possible because the axes of the bores, lamps, reflector curve, and mounting grooves are oriented in the same direction.

In addition to providing convenience of assembly and disassembly, this mounting construction permits the reflector 40 to operate at a higher temperature and to be properly shielded for proper cooling as will bebrought out in more detail hereinafter. The reflector. will operate at a higher temperattue because the oxide coating 40b in Fig. 7, having a higher melting point than the aluminum base 49a, has not been pierced by mounting fasteners for the reflector; because no joined dissimilar metals exist to melt at their junction at a lower temperature than either alone by the so-called eutectic eifect because the reflector 40 has only one metal, aluminum; and because the aluminum oxide coating, having a higher melting point than aluminum, is not pierced by and is free of any material having a greater heat conductivity. Also, the

side walls

45 and 46, back wall 38 and front wall portion 42 serve as a shield for the reflector 40 to expose only the desired reflecting surface area 401' to the lamps 50 while the remainder thereof is shielded by ceramic or fire brick material having high heat resistance and low heat conductivity characteristics.

The assembly of the unit 36 into the base housing should be readily apparent. After the

side walls

45 and 46 have been moved toward each other to properly mount reflector 40 and lamps 50, then fire

brick walls

38, 39, 40, 42, 45 and 46 will be cemented or otherwise secured together to form the assembled unit 36. Then, after

plates

32 and 34 are placed in channel 16 in their final positions, the assembled unit 36 may be telescoped into the rectangular channel 16 through its open end 16a until its bottom wall 39 engages bottom plate 32 supported by bottom flanges Zia-24a.

Alternate constructions readily suggest themselves. Lamps 50 and reflector 40 may be placed in any suitable position around the enclosed heating chamber 47 with the reflector 4t and lamps 50 being substituted as a wall for the bottom wall 39, back wall 38, or either

side wall

45 or 46 depending on the need, size and shape of the object being heated within chamber 47. For example, in bottom heating wherein reflector 40 serves as a bottom wall, it is preferred that a clear quartz, vycor or any high melting borsilicate glass plate of inch to /2 inch thickness be used to act as a shield for the heat source and to support the object being heated. This glass plate is preferably of the proper optical properties (ground and polished), which may as the occasion arises difluse' or concentrate the light heat energy over the plane or surface formed by the object being heated. Also, lamps and reflectors may be used simultaneously in a plurality of the walls forming the heating chamber 47, such as opposite side and top walls. Also, for kilns or furnaces of the simplest design, lamps 50 and reflector 40 may be supported by a skeleton construction on vertical supports, such as in any suitable manner by corner members 1114, without any substantially enclosing fire brick or insulating construction such as back wall 38, bottom wall 39, etc. This type construction will facilitate making a kiln or furnace for any size or geometric shape desired for immediate use with minimum of economic expenditure. However, it should be realized that when the lamps 50 are deenergized, the object previously heated in this skeleton construction will cool rapidly since it is not enclosed in a heating chamber 47 and hence crazing may occur.

In operation of the kiln or furnace at the high temperatures desired, it is necessary to cool some of the component parts in a suitable manner and especially to cool the reflector 40, terminals 50b and 500, leads 51 and 52, and

connections

53 and 54 to protect them against overheating. Herc, means is provided for cooling the reflector and these other component parts by the circulation of coolant fluid in the manner shown by the arrows in Fig. 3. Although this coolant fluid may be any type gas or liquid, it is shown herein as air. This means includes a hood 60 operatively connected by telescopic association of its flanges 66a and 66b over the rectangular cross sectioned periphery, formed by walls 38, 42, 45 and 46 of unit 36, into abutting relationship with the top of corner members 1114 of base housing 10 for closing the upper open channel end 16a of base housing 10 and includes an electrically driven coolant pump or blower 62, comprising an electric drive motor 62a and a housing 621) for an impeller driven by said motor, mounted on hood 60 for sucking in air and for driving it into the hood 60 to ,circulate along a path through the hood, over and in thermal contact with a surface on the upper or other side of the heat conductive reflector 40 from heat lamps 56 approximately coextensive with and approximately aligned with reflecting surface 401-, as bounded by walls 38, 42, 45 and 46, so that the cooled surface is approximately coextensive with the surface receiving the radiant energy; over at least a portion of the leads 51 and 52; over connections 53 and 54; over terminals 5% and 50c; through channels 450 and 460 in the side walls 45 and 46 formed between side wall bases 45a and 46a and side wall bars 451) and 46b; over at least a portion of the outer surface of the opposite side Walls 45 and 46; and through opposite apertures in the base housing ll) formed between adjacent corner members 11, 14 and 12, 13 for reducing the operating temperature of the reactor, connections, leads and terminals while the side walls 45 and 46 shield the vitreous envelopes 59a of lamps 50 from coolant contact and while reflector 40 and side walls 45 and 46 prevent entry of the coolant into the enclosed heating chamber 47. Hood lips 600, depending from and integral with hood flanges 6%, close the upper ends of the discharge passageways of channels 450 and 460 so as to direct the cooling air against terminals 5% and 50c and against leads 51 and 5'2 located in the corners of channels 450 and 460 to assure adequate cooling thereof. This cooling action permits the kiln to operate at a high temperature while protecting the components thereof from overheating. For example, reflectors 40 may be heated to 1600 degrees Fahrenheit, well over the melting point of aluminum, with the aforementioned type lamps 50 if blower or pump 62 is not energized. However, when the blower 62 is circulating the coolant fluid along the flow path shown by the arrows in Fig. 3, the temperature of the reflector 45 may drop to 300 degrees Fahrenheit.

Alternate methods of cooling the reflector readily suggest themselves, In Fig. 3, pump or blower 62 forces the air as a coolant fluid along the path shown by the arrows to cool the components and to displace the hot air within the hood. Instead, pump 62 may be used as an exhaust pump to suck the cool air in through the openings in the

side walls

45 and 46 so that the flow will be along the same path but in the opposite direction to the arrows. Also, the circulated coolant fluid might take the form of water or other suitable refrigerant circulating through pipes in thermal contact with the upper surface of reflector 40 and in the general environment of the terminals 56b, 56c and leads 51 and 52. Also, cooling by circulation of coolant fluid may be obtained by placing thin sections of a metallic or non-metallic, high thermalconductivity material on the reflector and the other components desired to be cooled so that heat may be drawn away from the component to the surface thereof most remote from heating chamber 47 by the normal course of thermal transmission in the material. This cooling may be accelerated by the use of a mechanically driven fan or blower, either sucking or blowing cool air over the thin sections.

The electric circuit controlling lamps 50 and blower, fan or pump 62 is shown in Fig. 6. Power to both is supplied through power lines L1 and L2 through a double pole double throw switch 64 having three positions: (1) lamps t and blower 6t deenergized, (2) blower 62 energized and lamps 5t deenergized, and (3) lamps 5! and blower 62 energized. The switch 64 is shown in Fig. 6 in its first position. The second position is achieved by swinging the switch 64 counterclockwise into engagement with its left-hand contacts to complete its circuit from power line L2 through the lower switch arm, line 65, blower 62, and line 66 to power line L1. The third circuit is completed by swinging the switch clockwise in Fig. 6 into engagement with its right-hand contacts to complete a circuit from power line L2 through switch jumper 64a, the upper switch blade of switch 64 and through two parallel paths back to power line L1 with one of the parallel paths extending through switch jumper 64b, the lower blade of switch 64, line 65, blower 62 and line 66 to energize blower 62 and with the second parallel path extending through line 55, bus bar 51a, branch wires 51b, connections 53, lamps 50 connected in parallel, connections 54, branch wires 52b, bus bar 52a, and line 56 to energize lamps 56. Hence, it should be readily apparent that the reflector and other components of the kiln are protected against overheating at all times since this circuit prevents energizing the radiant energy lamps 50 without energizing the coolant fluid pump or blower 62 so that the fan or blower will always operate While the enclosed chamber 47 is being heated by the energized lamps 50. It should be readily apparent that a thermalcouple wire junction may be used to check the temperatures of reflector 4t), terminals 50b and 560, leads 51 and 52, and the enclosed heating chamber 47 to open or close one or both of the parallel circuits in Fig. 6 from switch 64 through lamps 5i) and blower 62 to protect the component parts of the kiln from overheating and to control the temperature within the enclosed heating chamber 47.

The use of the kiln should be readily apparent. Switch 64 is thrown to the right-hand position in Fig. 6 to energize both the blower 62 and lamps 59. Since the lamps 50 heat up instantaneously, the object to be heated may be placed directly under the infra-red lamps 56 by placing it on top of the bottom wall 39 within the heating chamber 47 when doors 29 are in their open position. The surface of the object and the top of bottom wall 39 are so located as to obtain a heat concentration on 'a plane or on the irregular surface of an object at a distance from the reflector 4% and lamps 50 determined by the distance from the focus of the reflector curve. enamels will fuse upon the heated object within one to four minutes. If many colors are to be used,'it is best to apply light colors first, fire the object, and then apply Most the dark colors later, such as in cloisine work. This is true because the various colors have different absorption properties. However, in most cases, all colors can be applied together. ron, silver, copper, gold and other metals can be used for enameling with this kiln.

The illustrated kiln construction has many advantages. First, the time required to bring the kiln to temperature is a matter of seconds as opposed to hours required to bring the conventional kiln to the operating temperature prior to the time one may insert materials for enameling, glazing, fritting, ceramic firing, porcelainizing, etc.

Second, the object to be heated may be loaded by the user without gloves into the heating chamber 47 at operating temperature. Unlike electrically wired kilns or muflie furnaces, the interior is not hot because the heating action takes place only when infra-red energy comes in contact with the object. This minimizes danger of burns, fires, etc.

Third, sineea long heat-up period is not required, the wall temperatures are kept to a minimum and minimum insulation is required. However, since fire brick has een provided in the walls in the illustrated construction, the object may be cooled slowly in the enclosed heating chamber 47, if desired, without any danger of crazing. However, it should be readily apparent that the major portion of the fire brick walls may be completely eliminated from the construction so that the heating chamber 47 becomes a heating zone bounded by the structural members of base housing 10 if crazing is no problem and a more inexpensive kiln is desired. However, the low ,heat reservoir of the illustrated kiln, with its short heatup time, permits completion of the enameling or finishing of the ceramic within a very short time after the lamps 50 are energized. The object can be economically heated quickly in the heating chamber 47 to the desired high operating temperature and have the coating baked thereon in a minimum time.

Fourth, reflector 4t) and the other components are protected against damage by overheating. The reflector 40 is shielded by

walls

38, 42, 45 and 46 to expose only the reflecting surface area thereof which is located directly opposite the upper surface having the circulated coolant impinged thereon. Hence, cooling takes place where the heat is the greatest and cooling takes place over the entire heated area. Also, reflector 40 is mounted in grooves in the ceramic or fire brick walls so that there will be no tendency to burn out at the mounting zones.

Fifth, this heat source 49 provides no harmful ultraviolet rays emerging from the heating chamber 47. Hence, colored glasses are not necessary but are helpful.

Sixth, the cost of construction is considerably cheaper than the cost of construction of an electrical resistance type or gas fired type conventional kiln.

Seventh, the cost of operationof this kiln would be a small fraction of that required for the operation of the conventional gas or electric type kiln because a low heat reservoir is required and the absolute minimum of energy to heat the object is used. Hours of initial heating are eliminated. I

Eighth, this kiln is safer to use than the conventional electrical resistance or gas fired kiln. There is no hazard of sagging electrical coils, which can be shorted, and there is no hazard of a gas explosion.

Ninth, localized areas on large objects may be enameliZed, glazed or porcelainized with this kiln or other heater constructions following the illustrated construction principles but having an open bottom adapted to be pressed against the localized area of the large object to be located at a proper distance from the focus Q of aluminum; making reflector 40 and hood 60 of aluminum; and making

walls

38, 39, 40, 42 45 and 46 of fire brick.

Various changes in details and arrangement of parts can be made by one skilled in the art without departing from either the spirit of this invention or the scope of the appended claims.

What I claim is:

1. In combination, a reflector, an electric radiant energy heat source located in spaced relationship to said reflector on one side of said reflector for emitting radiant energy against said reflector for heating an object to a high temperature in a heating zone, said radiant energy heat source comprising a vitreous envelope having opposite ends, having two electrically conductive terminals operatively secured to said opposite ends of said envelope, and having means for transforming electrical energy into radiant energy extending through said envelope and operatively connected to said terminals, leads from a common electrical source to each of said terminals, an electrical connection between each lead and its assooiated terminal, means for circulating coolant fluid in thermal contact with the other side of said reflector, at least a portion of said leads, said connections, andsaid terminals for reducing their operating temperatures, and means for preventing coolant fluid circulation through said heating zone to reduce the temperature thereof.

2. In combination, opposite walls forming a heating zone therebetween for temperatures of at least 1000 C., a reflector formed of heat conductive material, an electric radiant energy heat source in said heating zone locatedin spaced relationship to said reflector on one side of said reflector for emitting radiant energy against a reflecting surface area on said one side, said electric radiant energy heat source comprising a quartz envelope having opposite ends, having two electrically conductive terminals operatively secured to said opposite ends of said envelope, and having a tungsten filament extending through said envelope and operatively connected to said terminals for transforming electrical energy into radiant energy and located in inert gas sealed in said envelope, leads from a common electrical source to each of said terminals, an electrical connection between each lead and its associated terminal, means operatively connecting said source and said reflector to said walls so that said walls serve as a reflector shield to expose only saidreflector surface area on said one side to said source, said opposite walls being formed of heat resistant ceramic material of low heat conductivity, said source being sufficiently high in temperature to melt said re flector and leads and connections and terminals if they are not cooled, means for circulating coolant fluid along a path over and in thermal contact with a surface on the other side of the reflector from said source approximately coextensive with and approximately aligned with said surface area, over at least a portion of said leads, over said connections, and over said terminals for reducing their operating temperatures belowrtheir 'melting point without cooling said envelope and heating zone, means for preventing circulation of said coolant fluid in said heating zone, and means for preventing energizing said radiant energy heat source without energizing said coolant fluid circulating means.

3. In a structure adapted to heat an object to a high temperature, interconnected opposite and connecting walls forming atleast a portion of a heating zone, at least one of said connecting walls comprising a reflector formed of heat conductive material, an electric radiant energy heat source mounted in said opposite side walls in said heating zone located in spaced relationship to said reflector on one side of said reflector for emitting radiant energy against a reflecting surface on said one side, said electric radiant energy heat source having terminals, leads from a common electrical source to each of said terminals, an electrical-connection between each lead and its associated terminal, said source protruding through both of said opposite walls with both said terminals and leads being located outside said opposite walls and said heating zone, means for circulating coolant fluid along a path over a surface on the other side of the reflector, over at least a portion of said leads, over said connections, and over said terminals for reducing their operating temperatures, and means for preventing coolant fluid circulation through said heating zone to reduce the temperature thereof.

4. In a structure adapted to heat an object to a high temperature, interconnected opposite and connecting walls forming at least a portion of a heating zone, at least one of said connecting walls comprising a reflector formed of heat conductive material, an electric radiant energy heat source in said heating zone located in spaced relationship to said reflector on one side of said reflector for emitting radiant energy against a reflecting surface on said one side, said electric radiant energy heat source having terminals, leads from a common electrical source to each of said terminals, an electrical connection between each lead and its associated terminal, said source protruding through both of said opposite walls with both said terminals and leads being located outside said opposite walls and said heating zone, means operatively connecting said source and said reflector to said walls so that said walls serve as a reflector shield to expose only said reflector surface area on said one side to said source, power driven forced circulation means energized independently of the heat from said source for circulating coolant fluid along a path over a surface on the other side of the reflector from said source approximately coextensive with and approximately aligned with said surface area, over at least a portion of said leads, over said connections, and over said terminals for reducing their operating temperatures, and means for preventing coolant fluid circulation through said heating zone to reduce the temperature thereof.

5. In combination, opposite walls, a curved reflector with the elements of the curve extending parallel to an axis, and an energy source for emitting energy against said reflector and being tubular in form with a longitudinal. axis, said opposite walls having through their inner faces coaxially aligned bores wherein said tubular energy source is mounted, said opposite side walls having in their inner surfaces aligned grooves extending along their elements parallel to the axis of said bores and curved in a plane transverse to the axis of said bores along the same curve as said reflector wherein opposite ends of said reflector are mounted, whereby said opposite walls, reflector and energy heat source are assembled by approach movement of said walls along said bore axis with the axes of said bore, source and reflector curve oriented in the same direction and are disassembled by separation r movement of said opposite walls.

6. In a kiln, a base housing comprising four parallel corner members each L-shaped in section and located at respective corners of a rectangle with adjacent flanges mutually coplanar to form a channel rectangular in cross section, and four connecting members secured at opposite ends respectively to adjacent corner members and each being L-shaped in section to form with one flange of each L-shape sides of the rectangle and with the other 7. In a kiln, a base housing having a channel with an i open end; a unit having interconnected walls forming at least a portion of a heating zone With said unit adapted to be telescoped into said channel open end into assembled relationship into said base housing, one of said walls extending across said channel and being located closest said open end being a reflector, and a radiant energy heat source in said heating zone located in spaced relationship to said reflector for emitting radiant energy against said reflector; a hood operatively connected by telescopic association to said unit and base housing for closing said open end of said base housing; and a coolant fluid pump for circulating coolant fluid through said hood and along a path over a surface on the other side of the reflector from said source for reducing the operating temperature of said reflector.

8. In a kiln, a base housing comprising four parallel corner members each L-shaped in section and located at respective corners of a rectangle with adjacent flanges mutually coplanar 'to form a channel rectangular in cross section, and four connecting members secured at opposite ends respectively to adjacent corner members and each being L-shaped in section to form with one flange of each L-shape sides of the rectangle and having the other respective flanges coplanar to form a border closed bottom end of the rectangular channel with an open upper end, said corner members extending down beyond said plane to form supporting legs for said kiln; a unit having interconnected walls forming at least a portion of a heating zone with said unit adapted to be tclescoped into said channel openend into assembled relationship into said base housing and supported at the bottom by said second recited flanges of said connecting members and laterally by said corner members and first recited flanges of said connecting members, one of said walls extending across said rectangular channel and being located closest said open end being a reflector, and a radiant energy heat source in said heating zone located in spaced relationship to said reflector for emitting radiant energy against said reflector; a hood operatively connected by telescopic association to said unit and base housing for closing said upper open end of said base housing; and a coolant fluid pump mounted on said hood for circulating coolant fluid along a paththrough said hood over a surface on the other side of the reflector from said source for reducing the operating temperature of said reflector. r

9. In a kiln, a base housing comprising four parallel corner members each L-shaped in section and located at respective corners of a rectangle with adjacent flanges mutually coplanar to form a channel rectangular in cross section, four connecting members secured at opposite ends respectively to adjacent corner members and each being L-shaped in section to form with one flange of each L-shape sides of the rectangle and having the other respective flanges coplanar to form a border closed bottom end of the rectangular channel with an open upper end, said corner members extending down beyond said plane to form supporting legs for said kiln, said base housing having one side of the rectangular channel forming the front side of the kiln with upper and lower U- shape channel members operatively connected at opposite ends to the corner members forming the opposite edges of said front side, and two doors slidably connected in said U-shape channels between a kiln open position in spaced apart relationship and a kiln closed position with said doors in abutting relationship; a unit having interconnected bottom, opposite side, back, top and front walls forming an enclosed heating chamber with said ront wall including said doors, said unit adapted to be telescoped into said channel open end into assembled relationship into said base housing with said bottom wall supported at the bottom by said second recited flanges of said connecting members and said opposite side walls of said unit supported laterally by' said corner members and first recited flanges of said connecting members, said top wall extending across said rectangular channel and being located closest said open end and being a metallic curved reflector with the elements of the curve extending parallel to an axis, and a radiant energy heat source being tubular in form with a longitudinal axis in said heating chamber located in spaced relationship to said reflector for emitting radiant energy against said reflector, said opposite walls having through their inner faces coaxially aligned bores wherein said tubular radiant energy heat source is mounted, said opposite side walls having in their inner surfaces thereof aligned grooves extending along their elements parallel to the axis of said bores and curved in a plane transverse to the axis ,of said bores along the same curve as said reflector, whereby said opposite side walls, reflector and radiant energy heat source are assembled by approach movement of said side walls along said bore axis with the axes of said bores, source, and reflector curve oriented in the same direction and are disassembled by separation movement of said side walls, said bottom and opposite side walls being formed of fire brick; a hood operatively connected by telescopic association to said unit and base housing for closing said upper open end of said base housing; and a coolant fluid pump mounted on said hood for circulating coolant fluid along a path through said hood over a surface on the other side of the reflector from said source for reducing the operating temperature of said reflector.

10. In a structure adapted to heat an object, a metallic reflector including on the reflecting side thereof an aluminum base of high reflectivity with an oxide coating having a higher melting point than the aluminum base, a radiant energy heat source arranged in spaced relationship to said reflector for emitting radiant energy against said reflecting side, and a non-metallic reflector mounting element having in a surface thereof an arcuately shaped groove mounting said reflector out of contact with other metallic elements, said element being formed of heat resistant ceramic material of low heat conductivity.

ii. In combination, a reflector, an electric radiant energy heat source located in spaced relationship to said reflector on one side of said reflector for emitting radiant energy against said reflector to heat objects to a temperature of at least 1000 C. in a heating zone, said radiant energy heat source comprising a quartz envelope having opposite ends, having two electrically conductive terminals operatively secured to said opposite ends of said envelope, and having a tungsten filament extending through said envelope and operatively connected to said terminals and located in inert gas sealed in said envelope for transforming electrical energy into radiant energy, leads from a common electrical source to each of said terminals, an electrical connection between each lead and its associated terminal, said reflector being sufliciently close to said source to be melted thereby if not cooled, said leads and terminals being sufficiently close to said source to have the electrical circuit therethrough broken by heat if not cooled, means for forced circulating coolant fluid in thermal contact with said reflector, at least a portion of said leads, said connections, and said terminals for reducing their operating temperatures below either their melting points or the temperature breaking the electrical circuit, and means for preventing coolant fluid circulation through said heating zone to reduce the temperature thereof.-

12. A structure, as set forth in claim 5, with a heating zone on-the inward side of said curved reflector, and means for forced circulating coolant fluid over the outward side of said curved reflector, said reflector being telescoped into said grooves snugly enough to prevent cooling of said heating zone by leakage therein of coolant fluid, said side walls being of non-metallic material.

13; In combination, opposite walls forming a heating zone therebetween for temperatures of at least 1000 C.,

a reflector formed of heat conductive material, an electric radiant energy heat source in said heating zone located in spaced relationship to said reflector on one side of said reflector for emitting radiant energy against a reflecting surface area on said one side, said electric radiant energy heat source comprising a quartz envelope having opposite ends, having two electrically conductive terminals operatively secured to said opposite ends of said envelope, and having a tungsten filament extending through said envelope and operatively connected to said terminals for transforming electrical energy into radiant energy and located in inert gas sealed in said envelope, leads from a common electrical source to each of said terminals, an electrical connection between each lead and its associated terminal, means operatively connecting said source and said reflector to said walls so that said walls serve as a reflector shield to expose only said reflector surface area on said one side to said source, said opposite walls being formed of heat resistant ceramic material of low heat conductivity, said source being sufliciently high in temperature to melt said reflector and to break by the heat from this source the electrical circuit throughout leads and connections and terminals if they are not cooled, means for circulating coolant fluid along a path over and in thermal contact with a surface on the other side of the reflector from said source approximately coextensive with and approximately aligned with said surface area, over at least a portion of said leads, over said connections, and over said terminals for reducing their operating temperatures below their melting point without cooling said envelope and heating zone, means for preventing circulation of said coolant fluid in said heating zone, and means for preventing energizing said radiant energy heat source without energizing said coolant fluid circulating means.

14, In a kiln, a base housing comprising four parallel corner members each L-shaped in section and located at respective corners of a rectangle with adjacent flanges mutually coplanar to form a channel rectangular in cross section, and four connecting portions secured to adjacent corner members and each being L-shaped in section to form with one flange of each L-shape sides of the rec-' tangle and with the other respective flanges coplanar to form a border closed bottom end of the rectangular channel with an open upper end, said corner members extending down beyond said plane to form supporting legs; and a unit having interconnected walls forming at least a portion of a heating zone with said unit adapted to be telescoped into said channel open end into assembled relationship into said base housing and supported at the bottom by said second recited flanges of said connecting portions and laterally by said corner members and first recited flanges of said connecting portions.

15. In a kiln, a base housing comprising four parallel corner members each L-shaped in section and located at respective corners of a rectangle with adjacent flanges mutually coplanar to form a channel rectangular in cross section, and four connecting portions secured to adjacent corner members and each being L-shaped in section to form with one flange of each L-shape sides of the rectangle and having the other respective flanges coplanar to form a border closed bottom end of the rectangular channel with an open upper end, said corner members extending down beyond said plane to form supporting legs for said kiln; a unit having interconnected Walls forming at least a portion of a heating zone with said unit adapted to be telescoped into said channel open end into assembled relationship into said base housing and supported at the bottom by said second recited flanges of said connecting portions and laterally by said corner members and first recited flanges of said connecting portions, one of said walls extending across said rectangular channel and being located closest said open end being a reflector, and a radiant energy heat source in said heating zone located in spaced relationship to said reflector for emitting radiant energy against said reflector; a hood operatively connected by telescopic association to said unit and base housing for closing said upper open end of said base housing; and a coolant fluid pump mounted on said hood for circulating coolant fluid along a path through said hood over a surface on the other side of the reflector from said source for reducing the operating temperature of said reflector.

16. In combination, a reflector, a radiant energy heat source located in spaced relationship to said reflector on one side of said reflector for emitting radiant energy against said reflector, pump means for forced circulating coolant fluid in thermal contact with said reflector for reducing the operating temperature of said reflector, means for energizing said heat source to a heat emitting relationship, means for energizing said pump, and control means for preventing energizing said radiant energy heat source by its energizing means without energizing said coolant fluid circulating pump means by its energizing means so that said pump means must always be energized when said heat source is energized so that the operating temperature will always be reduced, said control means including means for energizing said pump means by its energizing means without energizing said heat source means by its energizing means.

References Cited in the file of this patent UNITED STATES PATENTS 714,373 Hewett Nov. 25, 1902 764,994 Dutertre July 12, 1904 1,231,196 Rankin et al. June 26, 1917 1,802,001 Brooke Apr, 21, 1931 1,905,811 Culver Apr. 25, 1933 2,131,484 Ringwald Sept. 27, 1938 2,358,718 Kautfman et al. Sept. 19, 1944 2,400,056 Wheat May 7, 1946 2,439,005 Jensen Apr. 6, 1948 2,497,676 Lashells Feb. 14, 1950 2,504,516 Goodell Apr. 18, 1950 2,599,029 Turner et a1. June 3, 1952 2,627,014 Kolb Jan. 27, 1953 2,707,745 Farr et al. May 3, 1955 2,764,664 Stewart Sept, 25, 1956 2,822,458 Hatch Feb. 4, 1958 2,844,699 Miskella July 22, 1958 FOREIGN PATENTS 338,816 Great Britain Nov. 27, 1930 484,199 Great Britain Apr. 28, 1938 256,197 Switzerland Feb. 16, 1949 892,950 Germany Oct. 12, 1953 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,981,819 April ac, lhl

' James Jo Gregory It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 64, for "resing" read resting column 4, line 5, for "57" read 47 same line 5, for "relationsihp" read relationship line 7, Tor "tchis" read this line 55, for "Fahreinheit" read Fahrenheit line 57, for "'Fahrehiheit" read Fahrenheit column 6, line 54,

for "reactor" read reflector column 13, line 23, for

"throughout" read through the'--.

Signed and sealed this 17th day of October 1961.

(SEAL) Attest:

ERNEST SWIDER H DAVID L. LADD Commissioner of Patents Attesting Officer USCOM M- DC UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, $981,819 April 25-, 15 61 James Jo Gregory It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below,

Column 2, line 64, for "resing" read resting -l; column 4, line 5, for "57" read 47 same line 5, for "relatiousihp" read relationship line 7, for "tthis" read this line 55, for "Fahreinheit". read Fahrenheit line 57,

for "Fahrehiheit" read Fahrenheit column 6, line 54, for "reactor" read reflector r; column 13, line 23 for "throughout" read through the'-.

Signed and sealed lTth day of October 1961.,

(SEAL) Attest:

ERNEST W. SWIDER i -v DAVID L. LADD Attesting Officer Commissioner of Patents USCOMM-DC