US 2707745 A
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Description (OCR text may contain errors)
ay 39 1955 E. A. FAHR ET A1.
HEATER 2 snets-sheet 1 Filed Aug. 18, 1952 INVENTORS. "//Epwnnpfnaamzd /Jmn QTHEISEN, :v
May 3, 1955 E. A. FARR ErAL I 297079745 HEATER Filed Aug. 18, 1952 2 Shams-Sheet 2 INVENTOM @Magg/ /eedwd By .jH N F? REISEN, j; 6'
r 7'0 @NE Ys L United States Patent ice iiatented May 3, 1955 HEATER Edward A. Farr and .lohn P. 'iheisem Columbus, Ind., assignors to Arvin Industries, Inc., Columbus, ind., n corporation of Indiana Application August 1S, 1952, Serial No. 394,873
4 Claims. (Cl. 219-39) This invention relates to a portable room heater or" the type embodying one or more electrical resistance heating elements and a fan or blower for discharging into a room air heated by the heating elements.
lt is an object of the invention to produce a heater which will operate automatically to maintain a substantially constant temperature in the room within which the heater is located. A further object of the invention is to produce a heater which will disseminate both radiant heat and a heated air stream. Still another object of the invention is to produce an automatically controlled heater which can be simply and economically constructed, which will be conveniently portable, and which will prove durable and effective in use.
ln carrying out the invention in its preferred form, we provide a casing, conveniently of metal, having interiorly a vertical partition dividing it into inlet and outlet chambers provided respectively with air-inlet and air-outlet openings. Associated with the outlet chamber is a forwardly presented reflector within which one or more electrical resistance heating elements is located. AThe outlet openings in the discharve chamber include one or more in such reflector, the arrangement being such that at least some of the air forced from the inlet chamber to the outlet chamber by a fan or other appropriate air-mover may escape from the outlet chamber through the holes in the reflector, passing in Contact with the heating elements en route. Desirably, the outlet chamber is provided with auxiliary openings above and below the rellector and arranged to discharge obliquely across the open front of the reflector.
Within the inlet chamber, we provide a temperatureresponsive element adapted to be responsive to the temperature of air drawn into the inlet chamber when the fan is operated. This temperature-responsive element, which is preferably adjustable, automatically operates a switch controlling the supply of current to the heating elements and the motor.
The accompanying drawings illustrate the invention:
Fig. l is a front elevation of a preferred form of heater.;
Fig. 2 is vertical section on the line 2-2 of Fig. l;
Fig. 3 is a fragmental horizontal section on the line 3 3 of Fig. l;
Fig. 4 is a rear elevation of the heater with the rear wall or cover removed;
Fig. 5 is a fragmental View similar to Fig. 4 but on an enlarged scale, indicating a preferred construction for the temperature-responsive element and the switch which operates it; and
Fig. 6 is a wiring diagram.
rlhe heater shown in the drawing embodies a hollow casing 1l) conveniently formed of sheet metal provided at its front with a front wall ll and at its back with a rear wall 12, the latter being removable. A vertically extending partition located intermediately ot' the casing lt) between the front and rear walls divides the interior of the casing into an inlet chamber' 14 and an outlet chamber communicating with each other through a large opening adapted to receive a rotatable fan 16. The fan 16 is mounted on one end of the shaft of an electric motor 17 supported from the partition 13 through a suitable bracket 18. The rear wall 12, desirably in its lower portion, is provided with a series of air-admitting openings 19. Feet 2i) support the casing above the floor or other supporting surface.
Opposite the fan 16 the front wall 11 o the housing is provided with an opening adapted to receive a reflector 22, preferably formed as a stamping of bright-surfaced sheet-metal in an elongated trough-like shape and provided with end walls 23. Conveniently, the longitudinal edges ot the reilector 22 and the edges of the end Walls 23 are bent outwardly to form flanges lying against the front face oi the front wall 11. Such anges and the open front of the reflector are desirably covered by a toraminous grill 25, which may be secured to the front wall ll by screws 26 passing through the aforesaid anges.
Within the reflector and extending longitudinally thereof is an electrical resistance heater shown as comprising three elements 23 of the sheathed type. As will be seen from Fig. 3, the elements 28 may be held in place by 4iorcing theln through holes provided in the end walls 23. Beyond the end walls 23, the conductors of the heating elements are interconnected in parallel by metal-strip connectors 3b.
'lhe inner or rear wall of the reflector 22 is provided with a multiplicity of perforations 3i so located that air forced forwardly by the lan lo will pass through such perfor-ations, in contact with the heating elements 28, and out through the foransinous grill 25. Desirably, the front wall 01' the heater 1l is provided with auX"iary outlet openings 32 defined by louvers 33 disposed to direct the air emerging from the openings 32 obliquely across the grill 23.
For a reason which will hereinafter become apparent, the heater in the drawing is shown as provided with an auxiliary heating element 35 in the form of an open coil ot resistance wire supported in front of the partition 13 through insulators 36.
Within the inlet chamber ld, and conveniently near the bottom thereof adiacent the inlet openings 19, we provide automtaic temperatore-responsive mechanism for controlling the current to the heating elements anc. to the motor. A preferred form of such mechanism is Shown in Fig. 5. lt compr'es a base 40 secured to the rear i'ace of the partition i3 having, near its bottom, an outturned ear 4l to which are secured in insulated relationship an upper Contact arm 42, an intermediate contact arm 43, and a lower Contact arm 44. rl`he lower contact arm 4d and intermediate arm i3 have cooperating controis 45, while the intermediate and upper arms have cooperating contacts 46; the arrangement being such that current will flow between the upper and lower contact arms only when both the contacts and contacts i6 intercngage.
The lower contact arrn 44, which is desirably of spring metal, is biased downwardly, but is adapted to be forced upwardly to cause interengagernent of the contacts 45 by a plunger d'7 vertically slidable in the lower wall of the casing lil. A spring 43 urges the plunger 47 downwardly to permit the contacts 45 to separate; but the plunger is so a"anged that engagement of its lower end with the floor will force it upwardly in the casing to elevate the arm 44 and close the contacts 45.
The upper contact arm 42, like the lower contact 4d, is desirably or' spring metal and is biased upwardly. To force the arm d2 downwardly and cause interengagernent or" the contacts 46, We employ a temperature-responsive element shown as in the form of a bi-metal strip secured to a bracket 51 pivotally supported on a horizontal axis from the base 4t). The strip Sil, which llexes upwardly upon increases of temperature, is provided at its outer end with an adjustable screw 52 adapted to bear on the outer end of the contact member 42.
It will be obvious that the temperature at which thc bimetal strip Sil operates to cause an interengagement of the contacts 46 will depend upon the position of the bracket 51 about its axis of pivotal connection to the base 40. To control adjustment of the bracket, there is secured to it a rigid adjusting member S4 having its remote t end bent into a U-shape to embrace a substantially circular cam 55 eccentrically mounted on an adjusting shaft 56. The shaft 56 (Fig. 2) extends through the partition 13 and front wall 1l, being provided in advance of the front Wall with a graduated adjusting knob 57. By rotating the knob 57 the cam 55 may be rotated to rock the bracket 51 about its axis and thus control the temperature at which the bimetal strip 50 acts to cause engagement of the contacts 46.
We have found that the temperature-responsive switch mechanism above described may be used to exercise an effective automatic control over room temperature if adequate precautions are taken to reduce the transmission of heat within the easing 1t) from the elements Z8 and 3S to the temperature-responsive element Si). The partition 13 serves to reduce such direct heat transmission, since it serves as a reflector reflecting forwardly heat emanating from the heating elements. Locating the temperature-responsive switch mechanism in a separate chamber from that containing the heating elements, adjacent the bottom of that separate chamber, and near the opening through which air enters tends further to render the temperature-responsive element more accurately responsive'to the temperature of the air entering through the inlet openings 19. To reduce direct heat transmission from the partition i3 to the temperature-responsive element, the partition may be provided with rearwardly offset bosses 69 on which the base 4% is supported by bolts 61, the bosses serving to hold the base 4i) in spaced relation to the partition, thus permitting some of the air entering the inlet chamber i4 to ow upwardly between the partition and the base 4t).
In addition to the parts above described, the heater includes a switch 65 and a pilot lamp 66.
As will be clear from the wiring diagram constituting Fig. 6, the heating elements 23 are connected in parallel with each other and in series with the heating element 35 and the double switch 4S, 46 to the terminals of a connector plug 67 by which the heater may be connected to a current-source. The motor 17 and pilot lamp 66 are connected across the heating elements so as to be cont trolled jointly with the heating elements by the switch 45, 46. The switch 65 is connected across the auxiliary heating element 35 and serves, when closed, to render that heating element effectively inoperative.
With the heater resting in vertical position upon the floor or other supporting surface, the plunger e7 will be elevated, thus forcing the contact arm 44 upwardly and closing the switch 45. lf the plug 67 is connected to a suitable source of current, energization of the heating elements and the motor 17 will depend upon the condition or" the contacts 46. lf the room in which the heater is located is at a temperature below that for which the control knob 57 is adjusted, the bimetal strip 5l) will be depressed to force the contact arm 4Z downwardly and close the contacts 46, thus causing current to he supplied to the heating elements and the motor 17. Operation of the motor causes air 'to be drawn into the inlet chamber 14 through the openings i9 and to be forced by the fan 16 through the openings 31 and 3?.. Some of the heat emanating from the heating elements 28 will be given up to the air which passes through the openings 31 and over the surfaces of the heating elements. Desirably, the heating elements 28 operate at a temperature suliicientl to cause them to glow; and as a result, a considerable amount of radiant heat will be emanated. The reflector 22 serves 45,. to reliect forwardly the radiant heat not emitted through the grill 25. Air escaping through the openings 32 is warmed by heat which escapes by conduction from the heating elements through the reflector.
As the heater continues to operate, the room in which it is located will be warmed, and the temperature of the air entering through the openings i9 will increase. ln response to the increased temperature of the air entering the inlet chamber 14, the temperature-responsive element 5d will ex upwardly; and when the room becomes heated to the temperature for which the control knob 57 has been set, upward flexing of the temperature-responsive element 50 will permit the contacts 46 to open, thus interrupting the supply of current to the heating elements and motor.
The pilot lamp 66 is desirably mounted, as indicated in Fig. l, so as to be visible from in front of the heater. It serves to indicate whether or not the heating elements and motor are being supplied with current.
it will be noted from Fig. 2 that the front wall 11 of the heater is disposed at an inclination, sloping generally upwardly and rearwardly from its lower edge. This constitutes a safety feature, lessening the chance that the heater will be placed against a wall or an article of furniture in such a way that air-outlet openings would be occluded and prevent dissemination of heat from the heater. Another safety feature resides in the louvres 33 and their effect in directing air obliquely across the open front of the reflector, thus militating against overheating by radiant heat of any object too near the open front of the reflector. The switch-closing plunger 47 is likewise a safety feature; for, since the switch 4S will be closed only when the plunger is forced upwardly by contact with a support, the heater cannot be operated while lying face-down on the oor with the air-outlet openings occluded. This latter feature forms the subject-matter of our prior Patent No. 2,59G,600, granted March 25, 1952.
We claim as our invention:
l. A heater, comprising a casing having a front wall, said casing also having air-inlet and air-discharge openings, the latter being in said front wall, electrical resistance heating means disposed in the casing in alignment with the air-discharge opening, a reflector for reecting forwardly heat emitted from said heating means, said rellector having air-passing openings in rear of said heating means, means within said casing for drawing air inwardly through said inlet opening and forcing it forwardly through the reector-openings, said reflectoropenings and said heating means being located in line with the discharge from said air-forcing means whereby air entering the reflector will ilow directly over and in heatreceiving contact with said heating means, and out said discharge opening, the front wall of said casing having an auxiliary air-outlet opening at one side of said air-discharge opening, and means for directing air emerging from said auxiliary opening obliquely across said air-discharge opening.
2. A heater, comprising a casing, a vertically extending partition dividing said casing interiorly into inlet and outlet chambers, said inlet chamber having one or more air-admission openings near its lower end, said partition having at its upper portion and wholly above said air-admission openings an opening for the pasasge of air from the inlet to the outlet chamber whereby air entering said air-admission opening will ow generally upwardly to said rst named opening, means in said casing for drawing air inwardly through said air-admission openings and discharging it through said outlet chamber and air-discharge openings, electrical resistance heating means in said outlet chamber for heating the air passing therethrough, and temperature-responsive means for controlling said heating means, said temperature-responsive means being located in the lower portion of said inlet chamber adjacent the path of air entering through said air-admission openings.
3. A heater, comprising a casing, a vertically extending partition dividing said casing interiorly into inlet and outlet chambers, said inlet chamber having one or more air-admission openings near its lower end, said partition having at its upper portion and wholly above said airadmission openings an opening for the passage of air from the inlet to the outlet chamber whereby air entering said air-admission opening will ow generally upwardly to said rst named opening, means including a rotatable, axial-delivery fan located in said first named opening in said casing for drawing air inwardly through said airadmission openings and discharging it through said outlet chamber and air-discharge openings, electrical resistance heating means in said outlet chamber for heating the air passing therethrough, and temperature-responsive means for controlling said heating means, said temperatureresponsive means being located in the lower portion of said inlet chamber adjacent the path of air entering through said air-admission openings.
4. A heater as set forth in claim 1 with the addition that there are two auxiliary air-outlet openings in said front wall, one of said openings being located above and the other below said air-discharge opening, said air-directing means directing downwardly air emerging from the upper auxiliary opening and directing forwardly air emerging from the lower auxiliary opening.
References Cited in the tile of this patent UNTED STATES PATENTS 1,406,912 Theolos Feb. 14, 1922 1,908,559 Roser May 9, 1933 1,942,758 )'essup Ian. 9, 1934 2,445,250 Steingruber July 13, 1948 2,583,754 Theisen Ian. 29, 1952 2,590,600 Farr et al Mar. 25, 1952 2,619,578 Jepson et al Nov. 25, 1952