US3157776A

US3157776A - Wall mounted heater

Info

Publication number: US3157776A
Application number: US146970A
Authority: US
Inventors: John P Sohn; Matthew C Kuepfer
Original assignee: Arvin Industries Inc
Current assignee: Meritor Inc
Priority date: 1961-10-23
Filing date: 1961-10-23
Publication date: 1964-11-17
Anticipated expiration: 1981-11-17

Description

Nov. 17, 1964 J. P. soHN ETAI.

WALL MOUNTED HEATER 5 Sheets-Sheet 1 Filed Oct. 23, 1961 v INVENToRs JOHN/.7 Soy/v AND By/VATTHEW l {HSW-5e @ma ,ww-M

Nav. 17, 1964 J. P. soHN ETAL 3,157,775

WALL MOUNTED HEATER Filed 001'.. 25 1961 5 Sheets-Sheet 2 I Li l I I/VVi/YTOES.

/v E oH/v AND BY /VATrf/EWCI Ku-PPE@ (A0. ad

A-r-romvsys.

Nov. 17, 1964 J. P. soHN ETAL WALL MOUNTED HEATER 5 Sheets-Sheet 3 Filed OOL. 25, 1961 Pa wie SUPPL Y INVENTOR. dof/NP Son/v A/vo BY Mfr/#EWG //EPFE@ Nov. 17, 1964 J. P. soHN ETAL 3,157,776

WALL MOUNTED HEATER Filed oct. 23, 1961 5 sheets-sheet 5 INVUVTORS. Jeff/v Scl/ml Ama BY MTN/EW C. Mfr/:Eg

A Tra/QNEf/s.

United States Patent C) 3,157,776 WALL MOUNTED HEATER John P. Sohn, Columbus, Ind., and Matthew C. Kuepfer, Battle Creek, Mich., assignors to Arvin Industries, Inc., Columbus, Ind., a corporation of Indiana Filed Oct. 23, 1961, Ser. No. 146,970 12 Claims. (Cl. 219-369) This invention relates to a wall mounted heater, and more particularly to a forced air wall mounted heater.

It is an object of the inventi-on to provide a wall mounted heater of compact size which can be mounted in a recessed position within a wall, which can be easily mounted in such recessed position in a pre-built wall, which will direct heated air away from said wall, and which can be removably mounted within a wall for ease of repair. It is a further object of the invention to provide such a wall heater which may employ a common inlet and outlet grille, and which may be employed in combination with distribution means for the direct distribution of heat to remote points.

According to one form of our invention, there is provided a housing mounted Iin a recessed position within a wall and having a forwardly presented opening disposed in an opening formed within said wall. A duct is mounted in said housing and is provided with a rst generally cylindrical portion in open communication with the interior of said housing and an open-ended second portion having one of its ends in open communication with said rst portion and its opposite end disposed in said housing opening. A grille extends across the wall opening and is provided with a compartmenting Wall connected to the end of the duct disposed in the housing opening to define an air outlet. The portion of the grille outside the extent of said compartmenting wall extends across the housing opening to form an air inlet for the heater. Conveniently, a plurality of resistance-type heating elements are mounted in the second portion of the duct, and a blower wheel is mounted in the first portion of said duct whereby said blower wheel pulls air into the housing through the air inlet, and moves the air through the first duct portion into the second duct portion where the air moving over the resistance elements will become heated and discharged through the air outlet.

Other features of the invention will become apparent from the more detailed description which follows and from `the accompanying drawings, in which:

FIG. 1 is a fragmentary view of a wall having a heater embodying our invention mounted therein, said heater and the structural wall components being shownv in dotted lines;

FIG. 2 is an enlarged front elevation of the heater shown in FIG. l, but with portions thereof being broken away;

FIG. 3 is a vertical section taken on the Vline 3-3 of FIG. 2';

FIG. 4 is a vertical section taken on the line'4--4 of F1o. 2; y

FIG. 5 is a wiring diagram for the heating elements shown in FIG. 2;V

FIG. 6 is a rear isometric view of the heater grille shown in FIG. 1; I

FIG. 7 is a fragmentary view similar to FIG. l, but showing a modied form of the heater grille;

FIG. 8 is an enlarged horizontal section taken on the line 8 8 of FIG. 7;

FIG. 9 is a vertical section taken on the line 9-9 of FIG. 8;

FIG. 10 is a fragmentary view of a wall having a modif fied form of our heater housing mounted therein, portions of said housing and the structural components of said wall being shown in dotted lines;

3,157,776 Patented Nov. 17, 1964 FIG. l1 is a vertical section taken on the line 11-11 of FIG. 10; and

FIG. l2 is an exploded isometric view of the housing shown in FIG. 10.

Our invention is characterized by the provision of a forced air electric heater which may be mounted in a recessed position in a wall between a pair of adjacent wall studs. Our invention is illustrated in the drawings as being mounted within a conventional wall structure which normally comprises a runner 15 upon which longitudinally spaced studs 16 are mounted. A material such as wallboard, plaster, or the like, forming a pair of

adjacent walls

17 and 19 is mounted on the opposed faces of the studs and extends from the ceiling to the oor. Adjacent the floor, a baseboard 18 is mounted on the wall 17 to provide an attractive trim for the lower edge of said wall.

Our heater construction is adapted to be mounted in a recessed position within such a conventional wall structure, and in the embodiment illustrated in FIGS. 1-4 comprises a housing 20, conveniently formed of sheetmetal and bent to form a continuous top wall 22, back wall Z4, bottom wall 26, and opposed side walls 28. As shown in FIG. 3, the housing 2t) has a fore and aft extent corresponding to that of the runner 15 and the studs 16, and as shown in FIG. 2, a lateral extent equal to the normal spacing between the studs 16. The side walls 2S on the housing 2t) are provided without turned flanges 29 secured to the forwardly presented faces of the studs 16 as by screws 30. As shown in FIGS. 2 and 3, a face plate 32, which may be retained in position by the screws 30, extends downwardly from the top wall 22 of the housing to partially cover yand enclose the front of said housing. The lower edge of the plate 32 terminates above the bottom wall 26 of the housing in an out turned flange 34 extending across the upper edge of an opening 36 formed in the wall 17.

Carried within the housing 20 is a sheet-metal duct comprising an upper generally cylindrically shaped por tion 38 extending transversely of the housing 20 above the plane of the wall opening 35, and a lower portion 40 extending from the cylindrical portion 38 into the wall opening 36. As shown in FIG. 3, the duct includes a rear wall 42 extending from the cylindrical portion 38 down to the opening 36, a front wall 44, and a pair of side walls 45 connected to the front and

rear walls

44 and 42. The front duct wall 44 extends from the Vlower edge of the cylindrical portion 38, to the opening 36 formed in the wall 17. Thus, the cylindrical duct portion 38 has an arcuate segment along its front and top in open communication with the interior of the housing 20, and the duct portion 49 is closed to the interior of said housing but in open communication with an arcuate segment of the cylindrical portion 3 along the rear and bottom thereof and the interior of the room to he heated.

For ease of maintenance, the duct 33 and 4t) is removably mounted in the housing 20. To this end, a pair of laterally spaced channels 46 are mounted on the lower housing wall 26 and are adapted to receive downwardly oifset tongues 47 mounted on the lower face of the rear duct wall 42. The tongues d'7 are releasably retained in the channels 46 as by springs 43 mounted on the upper housing wall 22 and bearing against a pair of plates 50 mounted on the front face of the duct adjacent the duct side walls 45. Conveniently, to space said duct from the rear housing wall 24, a pair of forwardly projecting bosses S2 are formed on the rear housing wall 24 to engage the rear duct wall 42 and thus define an insulating air space between the duct and housing. As shown in the drawings, the top and sides of the duct are also spaced from the adjacent walls of the housing 20 and the tongues 47 hold the bottom wall spaced from the housing so that said duct is surrounded by a layer-.of insulating air.

Mounted in the duct portion 33 is a cylindrically shaped blower wheel d having axially extending blades S5 connected at their ends to a pair of end plates 56. The blower wheel 5d is carried on an axle 57 rotatably mounted inthe duct end walls l5 and projecting out-I wardly from one of said end walls for connection to a driving motor 5S mounted within the housing Zit. As shown in FlGS. 2 and 3, a plurality of electrical resistance heating elemnts 64 are disposed wholly within the extent of said duct portion dit. Conveniently, said resistance elements 6d are mounted in a plurality or" insulators et) mounted in the duct end walls i5 and a plurality of insulators 62 rigidly connected lto the front and rear duct walls Lid and d2, supporting said resistance elments and crossbracing the duct portion dit. ln this manner, the blower wheel Se will pull air from the housing into the cylindrical duct portion 38, and then force said air downwardly through the duct portion dil past the heating clements ed for discharge of the heated air through the end of the duct portion lll opposite the duct portion 5S.

To provide the desired air movement through the housing and duct, a grille 65 extends across the wall opening 36. As shown in FlG. 6, the grille 65 has a peripheral wall do abutting lthe wall i7 adjacent the opening 36 and integral with la pair of vertically extending braces 67 through which mounting screws 6l extend for reception in apertured ears d3 formed on the duct portion 4th. An inwardly projecting wall dS is mounted on the grille d5 in spaced relation to the top and lateral stretches of the grille wall 66 and is press-fit into the open end of the duct portion di). Thus, the wall 68 compartments the grille 65 so as to form an air outlet for the heater within the extent of said wall 63 and an air inlet for said heater outside the extent of said wall d3. Conveniently, the

peripheral grille wall dd has an inwardly extending flange 69 which cooperates with the wall d@ to support an open mesh filter 'tl extending over the air inlet section of the grille 65. With the air inlet being disposed at the top and sides of the air outlet, there will be -a reduced tendency of the heater to streak the wall i7 immediately adjacent the wall opening 36 in which the heater is mounted. This separation of the air inlet and outlet also separates the movement of the unheated air moving into the heating housing 2b from the heated air-being discharged from the duct portion d@ to thus permit the housing 2li to cnvelop the `duct with a layer of unheated air creating an insulating barrier between said duct and the structural components of the wall.

Not all rooms will requirethe same amount of heat,V

but it is a relatively expensive matter to constructV different size heaters to vary their output. Therefore, the resistance elements ed are wired inthe manner illustrated in FIG. 5 in lwhich a pair of lead-ins 7d from a power supply are connected to the terminals D and E of a junction box, and the remaining terminals A, B, C, and F of said junction box are connected to the dierent resistance elements 64. Thus, by bridging across the different terminals of the junction box, ditierent resistances ed can be energized to cause the heater to produce diiferent heat outputs. Y

In certain instances, it may be desirable to discharge the heat created by the elements dll at points remote from the heater, as under a window located at arpoint remote from the heater. To this end, we provide the discharge grilletrunk assembly illustrated in FlGS. 7-9. ln such assembly, the grille comprises an outer peripheral wall 78 set in the opening formed in the wall i7 and connected to the housing 2li as by brackets dil. The kforwardly presented edge of the grille `wall'fri is turned inwardly, as

. at 82, and supports an openV mesh filter Sd forming the air inlet for the heater. Carried within the extent of the wall 73 and spaced from the top and lateral structures thereof is a generally i.-shaped open-ended conduit dii having one of its ends press-fit in the open end of the duct portion du and its opposite end 9 projecting outwardly through an opening S8 formed in a lateral stretch side wall 7S. An elongated trunk 90 of any desired length is connected to the outer end 89 of the conduit tid and forms an extension thereof. As shown, the trunk 9d extends along the baseboard 18 and is provided along its length with openings 92 for distributing the heated air discharged from the heater at points disposed along the wall i7. ln this embodiment of our grille, as with the other embodiment of our grille previously described, the air inlet -by which air is moved through the screen 8d into the housing 2@ is wholly separated from the air outlet formed by the duct portion itl and conduit 86, so that the duct containing the heating elements 64 is spaced from the housing wall Ztl by an enveloping layer of insulating inlet air.

As will be apparent, the wall heater illustrated in FIG. 2 requires a relatively deep vertical opening to be formed in the wall 17 in order that the heater may be mounted in its recessed position between a pair of adjacent studs i6. When such heaters are installed during the course of building the wall, this poses no problem. However, if such a heater isv to be installed in a pre-built wall, the configuration of the housing 2l) would require that a large portion of the wall 17 to be broken out, the heater installed, and then a portion of the Wall which was broken out be reconstructed over the recessed heater. To overcome this ditliculty,.we provide the housing structure illustrated in FIGS. l0-12 which requires only a relatively small opening to be formed in such a wall surface. Again in this modification, our heater is mounted between a pair of adjacent studs 16 mounted on a runner l5', with

walls

17 and 19 being secured to said studs. The housing shown in FIGS. 10-12, however, comprises a pair of opposed sheet-

metal shells

95 and 96. The upper shell includes an arcuate panel 97 forming the top and rear upper shell walls and connected at'its lateral edges to a pair of side walls 98 whose lower edges comprise obliquel ly downwardly angled rear stretches 99 and horizontally disposed forward stretches 19t). The forward edges of the ywalls 97 and 98 are connected to a front wall 101 whose'lower edge terminates in a forwardly projecting flange luz adapted to abut against the lower edge of an opening 36 formed in the wall 17 The bottom shell 96 comprises a panel i035 forming the bottom and rear walls of the lower shell 95 and connected at its lateral edges'to a pair of side walls 104. As shown in FIG. 12, the upper edges of the side walls 104 have forwardly disposed horizontal stretches 105 corresponding to the stretches lili! of they shell 95 and rearwardly disposed upwardly angled stretches 106 corresponding to the stretches 99 on the shell 95. Mounted on the inner faces of the side walls 104 andthe back wall of the panel liti?) is an upwardly projecting rim lil?, and a shorter pair of rims lith are mounted on the side walls 164 in alignment with the edge stretches 1% of said side walls.

As shown in FIGS. l0 and 1l, the

shells

95 and 96 have arfore and aft extent corresponding to the depth of the studs i6 and a lateral extent corresponding to the spacing between an adjacent pair of said studs. To mount the housing formed by the

shells

95 and 96 in a recessed position within ya wall, it is merely necessary to cut the opening 36 in the wall 17 such that said opening. has a lateral extent equal to the distance between a pair of `adjacent studs -16 and a vertical depthgonly slightly greater than the distance between the front panel lill and the rear wall of the shell 95. The housing may be inserted through this relatively small'opening 36 by first inserting the shell 95 into said opening. During such insertion, the shell is placed on the runner l5 with its face plate itilV presented upwardly, and thenris inserted rearwardly and upwardly in behind the wall i7', the

curved configuration of the panel 97 guiding said shell Yirito an upright position until the flange 192 abuts the upper edge of the openingV 362 While holding the shell 95 inits recessed position behindV the wall l, the Vshell.

96' is inserted into the opening 36. Said shell is inserted at a rearwardly angled orientation until the rear wall formed by the panel 103 is in alignment with the rear wall formed by the panel 97 and the forward edge of said panel is in alignment with the front edge of the runner The two shells are thus in vertical alignment, and the upper shell 95 may be released so that its

lateral edges

99 and 100 are received over the rim 106 in abutting relation with the

lateral edges

106 and 105, respectively, of the lower shell, the

rims

107 and 108 insuring that the two shells are retained in their intertting engagement. As they are inserted into the opening 36' both of the

shells

95 and 96 must be swung into an upright position. The angled edges 99-100 and 10S-166 on said shells, however, permits such swinging movements to be accomplished with the use of an opening 36 having a relatively small height.

The duct assembly containing the blower wheel and its motor and the heating elements may be assembled as a subassembly and then inserted into the opening 36 after the housing formed by the

shells

95 and 96 is inserted in said opening. Conveniently, in order that said duct assembly may be releasably retained in the housing in cocked position, the upper shell 95 is provided with a pair of bosses 52 corresponding to the bosses 52 and the lower shell 96 is provided with a pair of channels 46 corresponding to the channels 46. It is also contemplated that the grille shown in FIG. 7 or the grille shown in FIG. 6 may be employed in combination with the housing shown in FIGS. lO-l2 depending upon the type of heat distribution desired.

We claim:

l. A wall mounted heater, comprising a housing having front, rear, side, top, and bottom walls mountable in a recessed position in a wall structure and having an opening formed in its front wall adjacent one end of the housing and disposed in an opening formed in said wall structure, a duct mounted in said housing and having a first generally cylindrical portion in open communication with the interior of said housing along substantially the entire length of s-aid first lportion and continuous with an :open-ended second portion closed to the interior of said housing and having one of its ends in open communication with said first portion and its opposite end disposed in said front wall opening, said duct having a vertical extent substantiaily larger than the vertical extents of the openings in said front wall and wall structure and a transverse cross-sectional extent less than the transverse cross-sectional extents of said front wall and wall structure openings, a cylindrical blower wheel mounted in said first duct portion, means for rotating said blower wheel, a plurality of heating elements mounted in said second duct portion, and a grille extending across the opening in said wall structure and operatively associated with said housing and duct to define an air inlet at said front wall opening and air outlet separated from said air inlet and connected to said opposite end of said second duct portion whereby said blower wheel will pull air into said first duct portion through said air inlet and housing and force said air over said heating elements for discharge through said air outlet.

2. A wall heater as set forth in claim 1 in which said housing comprises mating upper and lower shells, said lower shell having rear and bottom walls interconnecting a pair of opposed side walls, said upper shell having rear and top-walls interconnecting a pair of opposed side walls matingly engageable with the side Walls on said lower shell, and said front wall on said upper shell having an outwardly projecting lip abutting the upper edge of said wall structure opening, the distance between said lip and bottom housing wall approximating the height of said wall structure opening.

3. A wail heater as set forth in claim 2 in which the mating edges of side walls on said upper and lower shells have downwardly angled stretches adjacent the rear walls 6 of said shells and generally horizontal stretches adjacent the front `of said shells.

4. A wall heater as set forth in claim 3 with the addition that the edges of said side and rear walls of the upper shell are supported on the edges of the side and rear walls of the lower shell, and at least one of said pair of shells being provided with a rim along its side and rear walls disposed in overlapping abutting relationship with the side and rear Walls of the other of said pair of shells.

5. A wall mounted heater, comprising a housing having front, rear, side, top, and bottom walls mountable in a recessed position in a wall structure and having an opening formed in its front wall adjacent one end of the housing and disposed in an opening formed in said wall structure, a duct mounted in said housing and having a first generally cylindrical portion in open communication with the interior of said housing and an open-ended second portion closed to the interior of said housing and having one of its ends in open communication with said first portion and its opposite end disposed in said front wall opening, said duct having a vertical extent substantially larger than the vertical extents of the openings in said front wall and wall structure and a transverse crosssectional extent less than the transverse crossasectional extents of said front wall and wall structure openings, means on said duct and housing adjacent said opposite end of said duct and front wall and wall structure openings lockingly engageable with each other for releasably locking said duct in said housing, biasing means acting between said housing and said first duct portion for releasably retaining said means in locked position, a cylindrical blower wheel mounted in said first duct portion, means for rotating said blower wheel, a plurality of heating elements mounted in said second duct portion, and a grille extending across the opening in said wall structure and operatively associated with said housing and duct to define an air inlet at said front wall opening and an air outlet separated from said air inlet and connected to said opposite end of said second duct portion whereby said blower wheel will pull air into said first duct portion through said air inlet and housing and force said air over said heating elements for discharge through said air outlet.

6. A wall heater as set forth in claim 5 with the addition that said housing has a back wall provided with at least one boss and said duct is disposed thereagainst by said biasing means.

7. A wall mounted heater, comprising a housing having front, rear, side, top, and bottom walls mountable in a recessed position in a wall structure and having an opening formed in its front wall adjacent one end of the housing in an opening formed in said wall structure, a duct mounted in said housing and having a irst generally cylindrical portion in open communication with the interior of said housing and an open-ended second portion closed to the interior of said housing and having one of its ends in open communication with said first portion and its opposite end disposed in said front wall opening, said duct having a vertical extent substantially larger than the vertical extents of the openings in said front wall and wall structure and a transv rse cross-sectional extent less than the transverse cross-sectional extents of said front wall and wall structure openings, a cylindrical blower wheel mounted in said first duct portion, means for rotating said blower wheel, a plurality of heating eiements mounted in said second duct portion, and a grille extending across the opening in said wall structure and having first and second wall portions disposed in spaced relationship, said first Wall portion being connected to said duct to form an air outlet therefor and said second wall portion abutting said wall structure adjacent the opening formed therein, the space between said first and second wall portions being open to the passage of air to define an air inlet for movement of air by said blower wheel into said housing for successive passage through said irst and second duct portions and discharge through said air outlet. A

8. A wall heater as set forth inclaim 7 with the addition that said second wail portion of said grille is provided with an inwardly projecting flange extending around and in spaced relation to said first wall portion, and a ilter is interposed between said flange and said first wall portion having a rst set of edges supported against said first wall portion and a second set of edges engaging said ange.

9. A wall heater as set forth in claim 7 with'the addition that said first Wall portion of said grille comprises a conduit having one of its ends connected to said duct and its opposite end connected to an elongated trunk extending outwardly from said grille and having openings formed therein for discharging the air from said duct at points remote therefrom.

10. A wall heater as set forth in claim 7 in which said rst wall portion is spaced from said second wall porftion to dispose said air inlet above and at the sides of said air outlet. v y

11. A wall mounted heater, comprising a housing hav- `ing front, rear, side, top, and bottom walls mountable in a recessed position in a wall structure and having an opening formed in its front wall adjacent the lower end of the housing and disposed in an opening in said wall structure, a duct carried in said housing in spaced relation thereto, said duct including a first generally cylindrical portion extending transversely of said housing above the plane of the opening formed therein and having a transversely extending arcuate segment along its front and top disposed in open communication with its interior of said housing, and a second open-ended portion closed f to the interior of the hou-sing and having one of its ends in open communication with an arcuate segment of said rst portion along the rear and bottom thereof and its opposite end being disposed in said front wall opening,V

said duc-t having a vertical extent substantially larger than ythe vertical extents of the openings in said front wall and wall structure and a transverse cross-sectional extent less than the transverse cross-sectional extents of said front wall and wall structure openings, means for removably mounting said duct in said housing, a cylindrical blower wheel mounted in said iirst duct portion, means for rotate ing said blower wheel, a plurality of heating elements mounted in said second duet portion, and a grille extending across the opening in said wall structure and op eratively associated with said housing and duct to deiine an air inlet for said tirst duct portion and an air outlet separated from said air inlet and connected to said second duct portion whereby said blower wheel will pull air into said irst duct portion through said air inlet and housing and force said air over said heating elements for discharge through said air outlet.

12. A wall mounted heater as set forth in claim 11 in which said duct comprises opposed front and rear and side walls, and said heating elements areV mounted on a -rst set of laterally spaced elongated insulators rigidly Steingruber Oct.V 13, 1953 2,808,237 Fosnes Oct. 1, 1957 2,870,319 Ford Jan. 20, 1959 2,988,626 Buttner June 13, 1961

Claims

1. A WALL MOUNTED HEATER, COMPRISING A HOUSING HAVING FRONT, REAR, SIDE, TOP, AND BOTTOM WALLS MOUNTABLE IN A RECESSED POSITION IN A WALL STRUCTURE AND HAVING AN OPENING FORMED IN ITS FRONT WALL ADJACENT ONE END OF THE HOUSING AND DISPOSED IN AN OPENING FORMED IN SAID WALL STRUCTURE, A DUCT MOUNTED IN SAID HOUSING AND HAVING A FIRST GENERALLY CYLINDRICAL PORTION IN OPEN COMMUNICATION WITH THE INTERIOR OF SAID HOUSING ALONG SUBSTANTIALLY THE ENTIRE LENGTH OF SAID FIRST PORTION AND CONTINUOUS WITH AN OPEN-ENDED SECOND PORTION CLOSED TO THE INTERIOR OF SAID HOUSING AND HAVING ONE OF ITS ENDS IN OPEN COMMUNICATION WITH SAID FIRST PORTION AND ITS OPPOSITE END DISPOSED IN SAID FRONT WALL OPENING, SAID DUCT HAVING A VERTICAL EXTENT SUBSTANTIALLY LARGER THAN THE VERTICAL EXTENTS OF THE OPENINGS IN SAID FRONT WALL AND WALL STRUCTURE AND A TRANSVERSE CROSS-SECTIONAL EXTENT LESS THAN THE TRANSVERSE CROSS-SECTIONAL EXTENTS OF SAID FRONT WALL AND WALL STRUCTURE OPENINGS, A CYLINDRICAL BLOWER WHEEL MOUNTED IN SAID FIRST DUCT PORTION, MEANS FOR ROTATING SAID BLOWER WHEEL, A PLURALITY OF HEATING ELEMENTS MOUNTED IN SAID SECOND DUCT PORTION, AND A GRILLE EXTENDING ACROSS THE OPENING IN SAID WALL STRUCTURE AND OPERATIVELY ASSOCIATED WITH SAID HOUSING AND DUCT TO DEFINE AN AIR INLET AT SAID FRONT WALL OPENING AND AIR OUTLET SEPARATED FROM SAID AIR INLET AND CONNECTED TO SAID OPPOSITE END OF SAID SECOND DUCT PORTION WHEREBY SAID BLOWER WHEEL WILL PULL AIR INTO SAID FIRST DUCT PORTION THROUGH SAID AIR INLET AND HOUSING AND FORCE SAID AIR OVER SAID HEATING ELEMENTS FOR DISCHARGE THROUGH SAID AIR OUTLET.