US1068763A - Electric heating device. - Google Patents

Description

W. s. HADAWAY, JR. ELECTRIC HEATING DEVICE. APPLIUATION FAILED JULY 24, 1908.

ATTOlNEY I 111 STATES PATENT orrron.

WILLIAMS. HADAWAY, an, or EAST ORANGE, EW JERSEY, ASSIGNOB, BY MESNL ASSIGNMENTS, r0 wnsrmenonsn unaware & MANUFACTURING COMPANY, A

CORPORATION or PENNSYLVANIA.

nnncrar'c HEATING nnvxcn.

- Specification of Letters Patent.- Application ma my 24, 190;. serials). 445,200.

- shall be simple and durable in construction and adapted for eneral heating purposes.

The heating device of my present invention comprises a metal cylinder to which heat is imparted by resistance ribbon that is insulated from its outer surface and is suitably disposed on the insulation in a zigzag form and held in 'osition under heavy pressure by any suita le means, such as steel band wire which is closely wrapped around the 1 cylinder and resistance element.

By constructing my improved heating de-' vice as above indicated, I am able to utilize a maximum amount of the heat which is generated in the resistance element, the pressures established by the band wire being suf- Lcient to prevent any relative movement between the several parts of the device on ac count of unequal expansion and contraction which usually occur'in devices of this character.

Figure 1 of theaccompanying drawings -is a planview, and Fig.2 a side elevation, of an electric heating deviceconstructed in accordance with my invention, the wrappings of insulating material and the metal armor being broken awayin' Fig. 2 to .d-isclosethe,

resistance ribbon Fig. 3 is a sectional View on the line II IIII of Fig.2, and Fig. 4 is a detail view of the resistance ribbon which is partially disclosed in Fig. 2.

Referring to the drawings, the device here illustrated comprises a hollow cylinder '1,

preferably constructed of sheet iron or other eat-conducting material, having st- ifi'ening rings 2 and 3 around which its ends are bent, a wrappin 4 of insulating fabric, a resistance strlp orribbon 5 and a metal armor 6, which' is wrapped around the cylinder after the resistance is properly disposed on the insulating wrapping 4, as herema er set iforth. It may be desirable to use :1 cyl inder of tile or, other electrical non-conductor in lieu of the conducting cylinder.

The resistance strip or ribbon' 5 is preferably constructed of a steel band or ribbon- Patented July 29, 1913.

which is provided with a plurality of slots 7 and 8 that extend inwardly from opposite edges and are arranged alternately so that a zigzag current-conducting ath is provided.

As shown in the drawings, t isribbon is laid on the insulating wrapping 4 in a zigzag form, the center lines of the main portions of the zigzag strip being parallel to the axis of the cylinder, but, while this form is considered preferable, it is not essential to my invention. The slots '7 and 8 are omitted at the bends of the strip (see Fig. 4) so that a materially greater current-carrying capacity is produced andthe danger of overheating and rupturing the strip at these points is avoided. For the same reason, the

slits 7 and 8 are also omitted from the ends .This sheet metal plate constitutes a portion of the armor 6 which further comprises a plurality of turns of steel band wire. 15 that are closelywound around the outer surface of the cylinder after the parts 4, 5, 6 and 13 v are in position. The primaryobject' ofthe steel band wire 15 is tocreate a relatively heavy pressure'between the metal cylinder 1 and the resistance ribbon, which are only separated by a thin wrapping of insulation,

in order to insure a uniform. expansion of;

the two parts and a transfer of a maximum amount of the heat generated in the resistance ribbon to the metallic walls of the cylinder that are exposed to the air or to some other liquid or fluid which it is desired to heat. Metal bands or rings may be shrunk onto the cylinder, to produce the desired pressure, instead of the band wirin As illustrated in Figs. 2 and 3, one en of the cylinder is provided with an enlargement 16 to which the terminal members 11 and- 12 are secured, holes 17 being provided. in the shoulderformed at'the junction of the enlargement with the cylinder, through which the resistance leads 9 and w 10 extend. The ends of the band wlre are secured to binding screws 17 and 18. The thickness of the insulation on the outer surface of the assembled resistance unit may be greater or less, according to the use for which the heater is intended. When it is used to heat water or other liquids flowing through it, the radiation of heat from the outer surface is prevented as far as possible.

While I believe that the resistance ribbon illustrated is preferable for use with my is improved heating device, my invention is not restricted to its use, and any suitable form of resistance element may be employed. It is also conceivable that structural modifications may be effected in the heating de- 20 vice itself Within the spirit and scope of ,my invention.

I claim as my invention:

1. An electric heating device comprising a cylinder of heat-conducting material, a

5 resistance element disposed on the surface.

thereof and insulated therefrom, and acompression metal sheath for the assembled cylinder and its resistance element comprising turns of wire disposed in compact side-by- 0 side relation and under tension.

2. An electric heating device comprising a hollow metal cyliiider, a resistance strip or ribbon disposed on its outer surface and insulated therefrom, a plate of heat-conductmg material wrapped around the cylinder and the resistance and electrically separated from the latter, and a wrapping of band wire for pressing the resistance strip or ribbon against the outer surface of the cylinder.

3. An electric heating device comprising a metal tube or cylinder, a zigzag resistance strip or ribbon disposed on the outer surface of the cylinder and insulated therefrom, the center line of the ribbon being parallel to the axis of the cylinder, successive wrappings of. insulating and heat-conducting material wound over the resistance strip, and

a close Wrapping of band wire surrounding the assembled device and forcing its parts together to increase the heat-conductivity from the resistance ribbon to the walls of the cylinder.

l. An electric heating device comprising a sheet metal cylinder, an insulating wrapping on its outer surface which is uninjured at high temperatures, resistance strip or ribbon laid on the surface of the cylinder from end to end in a zigzag form, said ribbon being. provided with a plurality of slots which extend inwardly from opposite edges and are arranged alternately to increase the length of the current-conducting path therethrough, and successive wrappings of insulation and sheet metal and an outer wrapping of band wire for pressing the other parts together.

5. An electric heating device comprising a hollow cylinder, a resistance strip or ribbon disposed on its outer surface and insulated therefrom, a plate of heat-conducting material wrapped around the cylinder and the resistance and electrically separated from the latter, and a wrapping of band wirefor pressing the resistance strip or ribbon against the outer surface of the cylinder.

6. An electric heating device comprising a tube or cylinder, a zigzag strip or ribbon disposed on the outer surface of the cylinder and insulated therefrom, the center line of the ribbon being parallel to the aXis of the cylinder, successive wrappings of insulating and heat-conducting material wound over the resistance strip, and a close wrapping of band wire surrounding the assembled device and forcing its parts together to increase the heat-conductivity from the resistance ribbon to the walls of the cylinder.

In testimony whereof, I have hereunto subscribed my name this 21st day of July, 1908.

WILLIAM S. HADAWAY, JR. Witnesses:

RUSSELL BARBOUR, BIRNEY HINES.

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