US1024234A - Electric heating unit. - Google Patents

Description

T. VAN ALLER.

ELECTRIC HEATING UNIT.

APPLICATION FILED MAYll, 1908.

1,024,234. Patented Apr. 23, 1912.

'1|mil mm"!lllllllllll uiu llllIIIIll"Ilillllllllllll l l Witnesses: W Inventor:

Tycho Van filler, @Z M 9 @W UNITED STATES PATENT OFFICE.

TYCHO VAN ALLER, OF SCHENECTADY, NEW YORK, ASSIGNOR T0 GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELECTRIC HEATING UNIT.

Specification of Letters Patent.

Patented Apr. 23, 1912.

Application filed May 11, 1908. Serial No. 432,023.

is uniformly and evenly distributed in a simple and eflicient manner.

One of'the objects of my invention is to provide a unit which may be readily adapted for heating various shaped surfaces, which may be easily modified so as to adapt it for distributing the heat over an irregular area, and which atthe same time can be applied to the part to be heated with a maximum of efliciency and simplicity.

In carrying out my invention I first wind the resistance conductor into the form of a helix. I prefer to have this helix closed on itself so as to obtain a maximum heating surface. In order-that the turns of the helix shall not come in electrical contact with each other, it is necessary that the resistance c0nductor be insulated. For this purpose I prefer to use a wire having an insulating oxid so that when the wire is heated up to a definite point a layer or coating of oxid is formed thereon which has insulating properties. The helixis then bent back and forth on itself so as to cover the desired area. When the unit has acquired the desired form it is flattened on itself byvbeing rolled or pressed until the opposite sides of the helix are in contact. In this way the effect of aflat strip is obtained without meeting the difliculties which are found in bending a flat.

strip edgewise upon itself.

In the accompanying drawing I- have shown my invention embodied in concrete form, Figure 1 showing the unit adapted for use on a flatiron, while Figs. 2" and 3 show a fragment of the coil before and after the flattening process respectively.

Referring to the drawing, the resistance wire 10 is first wound into a closed helix as shown, although the turns of the helix may be spaced apart if desired. The particular wire used in this helix forms no part of my invention although I prefer to use a wire which when heated will become coated with an insulating oxid. Such a wire is disclosed in the patent to John T. H. Dempster, No. 901,428, and contains nickel, chromium, manganese and iron. The wire may be heated to form the oxid by passing a current through it, it being desirable to first separate the turns by drawing out the helix so that the current will pass from end to end of the wire. It is obvious that the wire may be coated with the insulating oxid either before or after it is formed into a helix. Vhen the helix is finally made it is laid upon the sursired shape is obtained, it is flattened by passing it through rollers, or by putting it in a press or in any desired manner. means, substantially the same result is obtained as if the resistance conductor were in the form of a strip bent back and forth, that is, an excellent heat-conducting joint is produced. With the strip, however, it would be extremely difficult to make the necessary bends, whereas with the helix the bending is accomplished in a simple manner.

While I have described my invention in connection with specific steps of a process of manufacture and arranged in a definite way, it should be understood that I do not wish to limit my invention thereto except in .so far as it is limited by the scope of the claimsannexed hereto.

What I claim as new and desire to secure by Letters Patent of the United :States, is,

1. A resistance unit comprising an insulated helical resistance conductor flattened on itself and bent back and forth to cover a desired area. a

2. A'I'GSlStfiIlC unit comprising a flattened helical resistance conductor bent back and forth in parallel lines to cover a desired area.

By this forth in parallel lines of unequal length to own metal, the opposite sides of each turn of cover a desired area. the coil being in contact with each other. 10 4. A resistance unit comprising an insu- In witness whereof, I have hereunto set latcd resistance conductor formed into a my hand this 9th day of May, 1908. 5 closed flattened helix and bent back and TYCHO VAN ALLER.

forth to cover a desired area. Witnesses;

5. A resistance unit comprising a coil hav- BENJAMIN B. HULL,

ing a surface insulation of the oxid of its HELEN ORFORD.

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