US 3488475 A
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.Fam 6, 1970 w. GRoNwoLDT y3,488,475
BAsEBoAnD ELECTRIC HEATING APPARATUS v k Filed oct. 25, 1966 5 sheets-Sheet 1 wf Av Av AWAY/Av2 mvznrof WALTER GRNwoLDT ATTCRNE YS Jan. 6,1970 w. GRNWQLDT 3,488,475
BASEB'OARD ELECTRIC HEATING APPARATUS Filed oct. 25, 196s Y I 5 snets-sneet a www Av NV Av Av Avv/Av AW mvENToR' WA LTER GRNWOLDT y zum "f ATTORNEYS Kam 69 E97@ w. GRNwoLnT 3,488,475
*A BASEBOARD ELECTRIC HEATING APPARATUS Filed Oct. 25, 1966 5 Sheets-Sheet 5 INVENTOR' WALTER GRNWOLDT ef @da ATTORNEYS 3m 6 M70 w. GRNwoLDT 3,488,475
' BASEBOARD ELECTRIC HEATING APPARATUSA Filed oct. 25, 196e 5 sheets-'sheet 4 |NvENToR w A LTER j :eRNwOLnT BY y Mwvwua Jan. 6, 1970 w. GRONwoLDT BASEBOARD ELECTRIC HEATING APPARATUS 5 Sheets-Sheet 5 Filed Oct. 25. 1966 INVENTOR WALTER GRNwoLoT 7 l M e l www@ ATTORNEYS United States Patent O ABSTRACT OF THE DISCLOSURE An easily mountable and demountahle baseboard heater comprising a one-piece stepped part for attaching to the base of a wall having a groove at the top and a projecting ridge at the bottom, a U-shaped bracket for connecting the ridge at one side and the bottom of a one-piece cover jacket, wherein the cover jacket has a bent-down upper edge for extending into the groove.
The present invention relates generally to electric baseboard heaters, and particularly to improved constructions of the housing and heating elements.
A particular embodiment of the present invention cornprises a baseboard heater housing with air slots and convector mounting, and is characterized by a housing having the following features wherein:
(a) The part which is to be fastened to the wall consists of one piece, wherein the lower wall-attached portion consists of two bent-away portions offset in parallelism with the lower wall-attached portion having a forwardly projecting ridge where the upper wall-attached portion carries a roof portion bent therefrom at a right angle, and where the upper edge of the latter has a groove recessed in its, both the upper and the lower Wallattached portions having recesses for attaching them to a wall;
(b) The carrier or bracket is approximately U-shaped whereby one vertical prong extends from about the upper edge of the mounting piece to the first bent portion, and the other vertical prong is shortened to such an extent that between the prongs the convector is adequately supported, and below the shorter prong there is a supporting piece;
(c) The convector is rectangular in form and is so disposed that it can be inserted or removed from the U-shaped carrier piece;
(d) The cover jacket comprises a horizontal holding portion which is disposed so that it covers over the roof of the wall-attached part with its depending edge fitting into the groove of the bent roof-forming portion of the wall-attached part, while the lower part of the cover jacket is formed as a vertical wall which has at the foot of it recesses for securing members, and its lower edge is bent around in such a manner that it extends underneath the carrying member, the horizontal and the vertical portions of the cover jacket being connected by an inclined portion with airholes therein.
-By means of the two bent portions, the baseboard heater is attached directly to walls which are already provided with baseboards that extend over the oor covermg.
The preferred embodiment of the convector of the present invention is distinguished by the following features:
(e) The convector consists of interchangeable plates which are mounted on a tubular body;
(f) In the tubular body there is at least one electrically heated tubular element;
(g) The space between the tubular body and the electrically heated tubular element is filled with a pulverulent oxide; and
(h) The electrically heated tubular element has at least one end of its provided with a solid filling of oxidic insulating material which has rendered solid by the introduction of water glass.
Background of the invention Baseboard heaters of the present invention usually have a housing with an adjustable air-exit slot through which a heat-exchanging sheet-metal tube is introduced to serve as the heating element. The latter can be heated by circulating warm water or oil, or by electric heating means. The regulation of the adjustable air-exit slots can easily experience a malfunctioning.
The' convectors of the prior are baseboard heaters are not easily mounted or dismounted for maintenance and repair.
Description of the invention It is, therefore, an object of the present invention to provide an improved electric baseboard heater which facilitates mounting and dismounting the convector.
Another object of the present invention is a baseboard heater without adjustable vents.
Still another object of the present invention is a baseboard heater having a convector with the heating elements embedded in a pulverulent material.
A further object of the invention is an improved seal for the pulverulent material contained in the convector.
Other objects and advantages of the present invention will become apparent upon further study of the specitication, claims and the accompanying drawings wherein:
FIGURE 1 is a transverse cross-section of a baseboard heater with the improved convector of the present invention mounted therein;
FIGURE 2 is a transverse cross-section of the new and easily mountable and demountable baseboard heater housing of the present invention;
FIGURE 3 is the transverse cross-section of FIGURE 2 with the improved convector of the present invention mounted therein;
FIGURE 4 shows in perspective a modification of the bracket or convector carrier member shown in FIGURES 2 and 3;
FIGURE 5 shows in fragmentary perspective a portion of the improved baseboard heater housing of the present invention with a convector having two parallel tubular heating elements inserted therein; and
FIGURE 6 shows in fragmentary perspective the improved convector.
In the present invention the difliculties of prior constructions are avoided by positioning the primary heating member in a three-part housing with non-adjustable air inlet and outlet passageways. In one specific combination the tubular electric heating element is embedded in a heat-indifferent pulverulent or granular electrically insulating heat conductive intermediate layer in the convection tube.
In the embodiment of the present invention having a pulverulent material, the core of the outer visible heating elements has positioned in its a copper convector tube. The hollow space inside this tube serves to support the tubular heating element which has a heating coil therein. The vacant space which remains in the copper convector tube after the tubular heating element has been inserted is filled with an electrically insulating oxide, electromagnesia MgO, preferably that of 0.07 to 0.37 mm. granule size. Because of the great fluidity and the high filling density, the vacant space is packed so closely that it has the highest possible heat conductivity. In this manner every possible heat loss is prevented and thereby the greatest possible efficiency is achieved.
For sealing off purposes, the side that is used for electric current connection is closed with a two-aperture cap, e.g. a Benninger cap, which is soft-soldered to the copper tube of the heating member. The other end of the heating member, after being completely filled with the granular electromagnesia, is hermetically sealed by pouring in ordinary water glass. Loss of the granulate from the heater tube with such a closure is rendered impossible. By being sealed off at both ends in this manner the MgO which is slightly hygroscopic will not absorb moisture and will remain in good condition for a maximum period of time.
A particularly unique feature of the present invention is the built-in positioning of the special heating tubes. The heating system is sealed off and, therefore, does not require any tubular conduits.
The baseboard heater is characterized by an unusually short heating-up and waiting time.
The invention is further clarified by FIGURE 1 of the drawings wherein the rear wall 1 in combination with the slider and holder bracket 2, the damper strip 4 and the cover jacket 5 form the outer portions of the electric baseboard heater. The heat convector 3 includes copper convector tube 6 in which are contained two high yield tubular heating elements 7 with diameters of e.g. 8.4 mm., with soft steel jackets. The heating coil is rated to deliver a maximum surface temperature of 400 C. at the convector tube 6. The heating elements 7 are deeply ernbedded in electromagnesia 8, and by reason of the high heat conductivity deliver their heat without loss to the copper convector tube 6 of the heat convector 3.
The electromagnesia has the following chemical composition:
sists of one piece in which the lower wall-attached portion is offset by two bends 9 and 10 into two parallel wallattached sections, the lower section having a projecting ridge 11 and the upper wall-attached section having a rectangularly bent roof 12 with a groove 13 along its upper edge, both the upper and the lower sections having recesses 14 for receiving fastening means;
(b) The slidable carrier or bracket is generally U- shaped with one prong 24 extending from about the upper edge of ridge 11 to the lower bend 10 of the wall-attached part 1, while the other prong 24 is shortened suicieritly to permit easy removal of the heat convector 3 and is provided with a lower holding portion 16;
(c) The convector 3 is rectangular and is adapted to be inserted into or removed from the carrier or bracket 2;
(d) The cover jacket 5 comprises a horizontall holding portion 17 adapted to cover the roof 12 of the wallattached part 1 and extend into the groove 13 with its bentdown edge 12, while the lower portion of the jacket 5 forms a vertical cover wall whose lower portion has recesses 19 to receive fastening members and is formed with an inturned lower edge 20 extending around the holding portion 16 of the carrier 2, and Where the horizontal and vertical portions of the jacket 5 are connected by an inclined wall portion 21 with air-exit slots 24.
The convector 3 of FIGURE 2 comprises a tubular convector body 6 upon which the lamellae convector plates or fins 26 of the convector 3 are fastened. The tubular convector body 6 is heated by an inserted electric heater element.
The baseboard heater housing shown in FIGURE 3 is very similar to the one shown in FIGURE 2, but with the difference that the tubular convector body 6 contains two electrically heated elements 7 and the space between the Mgo Sto Fezoa Cao Nato A1203 B203 Tio EMN 1, EMN 1g, percent 97.60 1.1 0.04 1.2 0.01 0.04 0. 01 t) EMN 2, EMN 2g. percent 96.31 2.0 0.10 1.5 0. 01 0. 07 0.o1 o
The specific gravity is 3.56 g./cm.3. heating elements 7 and the tube 6 is filled with a pulveru- The melting point of electromagnesia is about 2800 C. The air which passes across the damper strip 4 should not reach a temperature higher than 60 C.
In another particular embodiment of the present invention, the tubular body is sealed off, at least at the end that has the electric connection, by means of a closure cap having openings therein for electric conductors, while the other end is sealed by solid electric insulation consisting, for example, of a reaction product of magnesium oxide and water glass solution.
Another and particularly preferred embodiment of the invention comprises two parallel tubular electric heating elements embedded in the pulverulent oxide of the tubular convector body.
As pulverulent electrically insulating oxides or oxide mixtures, those which have very good heat conductivity with good electric insulation properties are suitable, for example aluminum oxide, beryllium oxide, zirconium oxide and magnesium oxide. Of these, the preferred material is magnesium oxide in the form of electromagnesia of granular sizes 0.07 to 0.35 mm.
It is preferred to limit the heat production of the electric tubular heater so that the maximum surface temperature of the tubular electric heating element is about 400 C.
FIGURE 2 shows the new and easily mountable and demountable baseboard heater housing with its air slots and convector mounting comprising the following elements:
(a) The part 1 that is to be fastened to the wall conlent oxide 8.
The construction of the convector of FIGURE 3 consists of a composite unitary structure. Through the pulverulent oxide there is good heat conduction between the tubular body and the electrically heated tubular element, even though the oxide is also a good electrical insulator. Moreover, the intermediate space is effectively sealed off over at least one end of the electrically heated tubular member. For making necessary repairs, it is still possible, without damaging the metallic parts, to replace the electrically heated tubular element.
FIGURE 4 shows in perspective a modification of the carrier member or bracket 2 on which the convector 3 is supported.
FIGURE 5 shows in fragmentary perspective a portion of the new baseboard heater housing with an inserted convector that is heated by two parallel tubular heating elements.
FIGURE 6 shows in fragmentary perspective the tubular convector body 6 with two electrically heated tubular elements 7 therein, and with the intermediate space between the heated elements 7 and the tubular convector body 6 filled with pulverulent oxide 8 which at one end of the electrically heated element 7 is converted into a solid mass of insulation by the introduction of water glass solution into the oxide zone 8 to be solidified. At the right hand end, the electric tubular heating elements 7 are held in position by a two-hole closure cap 27 which fits over the tube 6.
The individual parts which constitute the new baseboard heater housing can be formed of various materials, as for example sheet metal. Since the heated air from the convector 3 which ows out through the air-vent slots 24 does not generally surpass a temperature of 75 C., the baseboard heater housing can also be formed of a sufficiently heat-stable plastic. Its parts can be adapted in such a way that the installation and servicing is greatly simplified. Since the convector is held in the housing by only a few narrow U-shaped brackets, the cold air which enters at the bottom will be quickly warmed by heat exchange and will pass outwardly through the slo-ts into the room to be warmed. In the preferred combination that is shown FIG- URES 2 to 5, the electric heating elements can be easily replaced.
In an especially convenient embodiment of this invention the tubular electric heating elemnts are provided with electric connection terminals at each end so that they can be energized by electric current from either end.
It will be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions and, accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.
What is claimed is:
1. In a baseboard type electric heater adapted for use along the base of a wall, the combination of a rear vertical wall, a bracket member abutting said vertical wall and extending therefrom, a convector mounted on said bracket member and a cover jacket having air outlets therein connecting said vertical wall and adapted to cover said convector, the improvement comprising:
(a) said rear vertical wall comprising a lower section and an upper section defining two parallel vertical sections offset by a first bend and a second bend, said lower section defining a forwardly projecting ridge and said upper section having a roof portion extending horizontally from said Wall, a groove in the upper edge of said roof portion and recesses for receiving fasteners in said upper and lower sections;
(b) said bracket member having a U-shape wherein a iirst prong has a length extending from about the upper edge of said projecting ridge to said first bend, a second prong is foreshortened whereby said convector is removably held, and said bracket member having a projecting holding portion below said second prong;
(c) said convector is rectangular in cross-section and is adapted to be mounted and demounted on said U-shaped bracket member; and
(d) said cover jacket comprises a horizontal holding section having a bent-down edge adapted to cover said roof portion and extend into said groove, and a lower cover jacket section defined by a vertical wall having a lower-turned-in edge adapted to engage said holding portion and an inclined air exit section connecting said horizontal holding section and having air ports therein defining said air outlets.
2. The heater of claim 1 wherein:
(e) said convector comprises interchangeable plates mounted on a tubular member;
(f) said tubular member has a tubular electric heating element therein;
(g) the intermediate space defined by the inside of said tubular member and said tubular electric heating element is filled with purverulent oxide; and
(h) one end of said tubular electric heating element has a closure defined by the reaction product of water glass and said oxide.
3. The heater of claim 2, wherein said tubular member has means for electrically connecting at one end comprising a closure cap adapted for the passage of electric conductors.
4. The heater of claim 2, wherein said insulating oxide is selected from the group consisting of aluminum oxide, beryllium oxide, zirconium oxide and magnesium oxide.
5. The heater of claim 4, wherein said insulating oxide is electromagnesia of magnesium oxide.
6. The heater of claim 5, wherein said electromagnesia has a granule size between about 0.07 and 0.37 mm.
7. The heater of claim 2, wherein said heating element has high output bodies deiined by soft steel jackets having a diameter of about 8.4 mm.
8. The heater of claim 2; 'wherein said heating elements have a surface temperature less than 400 C.
9. The heater of claim 1, wherein said lower cover jacket section defined by a vertical Wall has recesses for fasteners.
References Cited UNITED STATES PATENTS 1,432,064 10/ 1922 Hadaway 338--241 X 2,063,642 12/1936 Vandenberg 338-238 X 2,815,431 12/1957 Paley 219-366 3,266,563 8/1966 Sinclair 165-55 X 3,340,382 9/1967 Lennox 219-544 3,371,192 2/1968 Rosenel 219-523 FOREIGN PATENTS 1,328,725 4/ 1963 France.
OTHER REFERENCES Plate; German utility model 1,911,693; Mar. 11, 1965.
ANTHONY BARTIS, Primary Examiner U.S. Cl. X.R.