US579459A - George ii - Google Patents

Description

M R m NA IE H TC I Hm Wm L HE (No Model.)

No. 579,469. Patented Mar. 23, 1897.

INVE'NTUR I i, AA ZWMM ATT DRNEY- UNITED STATES Farsnr lrEORGE ll. lVlll'lTlNGllAM, OF BALTlMORE, MARYLAND.

SPECIFICATION forming part of Letters Patent 579,459, dated March 28, 1897.

Application filed January 30, 1896. Serial lie. 577,859. (No model.)

To all whom, it may concern.-

Be it known that I, GEORGE H. 'WHITrrNG HAM, a citizen of the United States, residing at Baltimore, in the State of lliaryland, have invented certain new and useful improve ments in Electric Heaters, of which the following is a specification.

My invention relates to an improvement in electric heaters, and has for its object to pro vide a tubular heater in which the resistancewire shall have its entrance and exit the same end of the tube and have efficient means for relieving the resistance-wire of the heat generated by the passage of the electric current.

For a full understanding of the invention reference is made to the accompanying drawings, in which- Figure 1 is a longitudinal central section showing the resistance-coils and two parallel glass tubes in the casing and the insulating heat-conducting filler. Fig. 2 shows a crosssection. Fig. 3 is a longitudinal section showing a modification in the construction of the two glass tubes. Fig. 4 shows a cross-section of the modified form seen in Fig. 4. Fig. 5 shows the heater in the form of a coil.

Referring to Figs. 1 and 2 of the drawings, the letterA indicates the resistance-wire, and D a'tubular casing, of iron or other material suitable for rapidly radiating heat, and which incloses the resistance-wire and is closed at its ends by screw-caps cl d. The resistance A enters the tube and also comes out at the same end. I

In the simplest form of my device there is within the tubular casing D and surrounding the resistance-wire a plurality of glass tubes shorter than the interior of the casin and a filling of clear loose sand it, which is employed as a heat-conducting medium between the wire and the outer casing and at the same time electrically insulates the wire therefrom. By this construe tion the heat of the wire is rapidly conducted to the outer casing, and the latter has its exterior surface exposed for radiation of the heat. It will be seen that the radiating-surface of the tubular easin g D is greatly larger than the surface of the wire it incloses.

The cap d at one end of the tubular ea. ing has two insulating bushings or plugs c, and the wire passes through one of these in en tering and through the other in coming out. Where the wire passes through the insulation 8, it is larger, to increase the conducting capaeity.

I employ two tubes 9 g, extending longitudinally of the exterior tube D. These serve to separate and electricallyinsulate the two stretches of resistance-wire inelosed in the radiating-tube D. In Figs. 1 and 2 the two glass tubes are side by side, parallel, and the entrance stretch 1, of wire, passes through the tube g and at the end crosses over, as at 9;, to the other tube g, and the exit stretch 53 passes through this second tube. Thus the wire which enters the radiating-tube at one end continues to the other end and then returns to the same end, where it enters. Thereby there is a double-resistance wire inclosed in the tube D, and the device is adapted and is more convenient for use in certain situations. The sand 72. is filled in both glass tubes, and also between the glass tubes and the inclosing tube D, so as to form continuous heat-conducting medium from the resistancewire to the said outer casing-tube.

The modification shown in Figs. 3 and employs two glass tubes g parallel with each other, but here the tubes are of different size, in order that the smaller tube may extend through the larger tube 9 In this form the entrance stretch 1, of wire, is coiled around the small tube, and therefore is in the larger tube or between the small and the large tube At the end the wire crosses, as at 0;, from the outside to the inner side of the tube, and the exit stretch 2 in this case extends straight through the inner tube back to the entrance end.

The ends of the tube D may be closed in any suitable manner.

A tube D,'filled with sand packed in and havin g glass tubes through which the resistancewire passes, sand being filled within as well as around the glass tubes, may be bent or coiled, as desired. This is illustrated in Fig. 5. During this operation of bending the metal tube the glass tubes will be broken into small particles, but these particles will still retain the tubular form and have the same relative position with respect to the sandfiller.

It will be seen that the resistance-wire is sustained in the tubular radiating-casing and prevented from sagging independent of both the filler and of said ease.

Having thus described in y invention what I claim as new, and desire to secure by Letters Patent, is

In an electric heater, the combination of a tubular easing; means for closing both ends thereof; a plurality of glass tubes shorter than the interior of the easing and situated. therein; a resistance-wire entering one end of the casing, extending through one of the glass tubes and returning through another of the tubes and passing out of the casing at the same end at which it enters; and a suit- 15 able granulated filler placed in the spaces in and around the glass tubes.

In testimony whereof I al'tix. my signature in the presence of two Witnesses.

GEORGE 1i. \Vll'l'l" INGHAM.

Witnesses:

CHARLES 1 MANN, J11, C. CALVERT ll'l'NEs.

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