US1004165A - Electrical immersion-heater. - Google Patents

Description

W. W. HANSGOM & A. L. LANGERMAN. ELECTRICAL IMMBsIoN HEATER.

APPLICATION FILED MAR. 20, 1909.

Patented Sept 26, 1911.

@p'l/ Mita-rar UNITED STATES 4PM ENT OFFICE WILLIMWALIACE HANSCOM AND ALBERT LEOPOLD LANGERMAN, OF SAN FRANCISCO, CLIFORNIA.

ELECTRICAL IMMERSION-HEATER.

Specication of Letters Patent.

Patented Sept. 26, 191i.

T o all whom it may concern:

. Be it known that we, WILLIAM WALLACE. HANsooM and ALBERT L. IgANonuiuAm'citizens of the United. States, and residents ot' the city and county of San Francisco, State of California, have invented certain, new and useful Improvements in Electrical Immersion-Heaters, of which the following is a specificatii..

The object'of our improvement is to provide an immersion heater, having arrangements of parts and combinations adapted to obviatejcertain defectscommon to immersionv heaters in present use, among which are the comparatively long time theyr take to heat a given volume ofliquid to a given temperature, their' subjection to loverheating when withdrawn from the liquid they are used to heat, and. the ditiiculty they present to thorough cleaning(f y l.

We havediscovered that Amuch of the time, -required to bring a given,volume of liquid `tua 'given temperature Aby the agency of electrical immersion heaters in common use'is expended in heatingthe parts of the heater'itself, especially .where such parts comprise a large `proportion of electrically non-Conducting material. And in the 4present constructions, the arrangement lis such that the air, being a very poor conductor, retards the rapid' heating of the apparatus. By our peculiar method of combining' the various parts of our device and of Winding the'wiyre, `we provide a construction that miniinlz'es the amount of insulating and supporting material employed, and mate' rially reducesjthe retardation due to the non-conductivity of air.

The utility of providing some means of preventing electrical heaters from overheatlng arises not only from the danger of destruction to the apparatus itself, but to the dangerof setting lire to inflammable materials in juxtaposition thereto. The ordinary fusing devices are useless for this purpose, because they are operated by an increasel in the strength of the current flowing through thacn-A Our protecting device operates in a different manner and does not require an increase in the current strength to cause an exercise of its function; 4

The necessity for keeping clean a heater that is intended to be immersed in a liquid required for human consumption, is obvious. Water contains impurities whichhfxn themselves to the surfaceot an immersion heater. By our construction'"our, beater may he thrown bodily into a vessel of water, and thoroughly cleaned, without endangering the inner parts by allowing moisture to reach them.

No accomplish our object hy means illustrated in the accompanying drawing of '\vhi`(.`:l1- i. 1 l g Figure 1 1s a vertical sectional View of our heater, showing fuse plug in position; Fig. 2 a plan view of our heater with parts of casing broken away to show interior mechanism; Fig. 3 the copper strip conductor, which forms an element 1n our .scheme for winding the coil. Fig. 4 is a @detail view ofcertain connecting means. f The drawings -are made to an enlarged .'scale in order to show the parts more clearly. i Similar numerals of reference mark simi- {lar parts throughout the several views.

Describing first the outer casing of our device, We provide a tube of metal 1 having a top 2, soldered thereon with solder having a very high fusing point. Attached to said ,top is a tube 3. which in contact with and similarly soldered to said outer casing by highfusing solder at 4. Said top is provided with an externally threaded covering 5, for our fuse plug 6, a`nd has a screw cap 7. Said top's also provided with an internally threaded coupling device 8, which engages .with external thread on the metal tube 9, ,the other end of tube 9, heilig provided with 'a hermetically sealed connectin device 10, which seals the inner part o said -tube against the entrance of moisture.

By the described construction of the outer covering ol our heater, the 'inner parts thereof containing the electrical conductors and insulating materials are protected from moisture, andthe whole device from connector 10 to the bottom of the outer casing may be thrown into a vessel of water and thoroughly cleaned. 4 Notwithstanding the water tight character of our outer envelop, the water in which our heater may be immersed is free to flow along inher tube 3, the top .and-bottom thereof being open.

Turning now to the inner parts of our device. We provide a Vcoil bearing tube 11, of thin brass which slips over the tube 3, inside tube 1; and the outside thereof we cover with a thin layer of mica insulation 12. Two contact and supporting brackets 13, and 14, are provided, bracket 14 being shaped to tit about the mica surface 12, ol tube 11, substantially in the position shown. But outside' of mica strip 12, and underneath bracket 13, is a conducting strip 15, saidtrip being laid against mica covering .12 from the top to near the bottom of the tube 11, and arranged in electrical contact with bracket 13. A layer of mica 16, is placed over the conducting si rip 15, and carried over the exposed surface of bracket 1 3. The exposed surface of bracket 14, issimilarly protected from electrical contact by mens of a mica covering 1T. T ubc 1l is now placed on a former and tightl Wound from top to bottom with the desiredy number of convolutions of bare high resistance wir 18, in such manner that a very small air space is left between the convolutions. Part of these windings pass over brackets 13 and 14 as indicated 1n Fig. 1, and are held there firmly in position. Brackets 13 and 14 serve to support the connecting devices andy fuses,

and, arranged as shown, obviate the necessit for using a large mass of heat absorbing su'stance. The bottom end of coil 18, is soldered to conductin strip 15, by solder having a very high using point, and the top of said coil is similarly soldered to bracket 14. The surface of said coil and the inter-sticos between the convolutions are then treated with a cold insulating cement 18' composed of silica withl a solution of silicate of soda.

Brackets 13 and 14 are made as small as the requirements of space and rigidity will allow, and takenin combination with the tube 12, conducting strip A15, and the thin mica insulating covering described, form an element having a. minimum of substance to be heated. Wherefore the temperature thereof is ,more quickly raised to the desired degree than is the case where more bulky parts are combined after the usual manner.

Bracket 13 is rovided with a connecting screw 19, to which is attached one of the insulated wires 20, from connector 10. Bracket 14 is provided with a conducting plate 28 insulated therefrom whereon is attached a connecting screw 21, to which is attached a second insulated Wire 33, from connector 10. Coil 18 is connected through said bracket 13 and through bracket 14, and conducting plate 2S, with connector 10. But bracket 14, also carries our fusing apparatus in circuit with said coil, in the manner which we will now proceed to describe.

Our fuse plug consists of a brass shell 22,

rovided with a copper cap 23. A screw 24 lsfitted to the center of said shell by means of a plug of insulating cement 25, having substantially the shape indicated, with,.'a convex surface below and a concavesurface above, and an aperture through its center stopped by said screw. A fuse wire 26,--is attached to said screw and to saidcppper Ilracket 121 is provided with' an' insulating strip of mica i7, which supports a conducting plate 28 and is attached thereto; and plate 28 and bracket 14 are bound together )y screws 29, tksaid screws passing through screw holes made so wide in plate 28 as not to touch said screws, said screws being also insulated from plate 28 by insulating washers 31 and 32.

Our fuse lug is arranged with the rim of shell 22 in electrical contact with late 28, screw 24, being electricallyl insu ated from plate 2S, and electrically attached to bracket 14. Therefore the circuit from bracket 14, to connector 10, is throu screw 24, fuse. wire 26, cap .23, shell conducting plate 28, connecting screw 21, and wire 33.

As aforesaid, our fuse plug does not operate by an increase in the strength of the current. As the specific resistance of conducting wires. increases with their temperature, a raised temperature in coil 18 would tend 4to send a smaller instead of a greater cur rent through the circuit.

So we cause our fuse to operate directly from thev heat imparted thereto by the raised temperature of the whole device. Coil 18 heats all of the element and with it bracket 14 and screw 24, shell 22, and fuse wire 26. Said fuse Wire being made to melt at a temperature a little above that of the whole apparatus in liquid, a 'rise in temperature to the required degree will melt said fuse and open the circuit.

We claim:

1. In an electrical immersion heater, heat ing conductors and ',dielectrics inclosed therein, a fusing device, a prottive covering for said conductors and dielectrics comprising an outer tube, having a bended por! tion in the lower part thereof, an inner tube having a cap adapted to fit outside said outer tube and being soldered thereto by high fusing solder, and havin its lower portion fitted to engage said ben ed portion o said outer tube and being soldered thereto by high fusing solder, a screw capped aperture in said cap adapted to protect and'give ready access to said fusing device, an interiorly threaded portion on said cap, a tube threaded exterorly at one end to engage said interiorly threaded portion, and a water-tight Velectrical connecting device at the other end of said tube.

2. An electrical' immersion hebr oomprsing an hermetically sealed protective coveringl having an inner tube, a coil-supporting tube surrounding said inner tube, l.

eating coil wound on said coil-supporting tubey and insulated therefrom, supporting brackets held in position on the tube by the windings of said coil, connecting screws on said supporting brackets, a water-tight electrical connector, and electrical connection between said water-light connector, connecting screws, brackets and said heating coil.

3. An electrical immersionheater coniprising an ermctically sealed protective covering' having an inner tube, u coil-supporting tube surrounding said inner tube, a heating coil wound on said coil-supporting tube and insulated therefrom, supporting brackets held in position von the tube by thdgwindings of said coil, a fuse plug supported on one of said brackets, having a fuse wire in circuit with said coil, a watertight connector, and electrical connections between said water-tight connector and said heating coil through said fuse plug.

4. An electrical immersion heater comprising an hermetically sealed protective covering having an innel' tube, a coil-supporting tube surrounding said inner tube, a heat-ing coil wound on said coil-suporting tube and insulated therefrom, a iiracket held inposition on the tube by the windings of said coil, a conducting strip having an upper end in electrical contact with said bracket and a lower end of said heating coil, a second bracket held in position on the tube by the windings of said coil `and electrically connected with the upper end of said heating coil, and insulated from said first bracket, a water-tight connector, and electrical connections between sa id water-tight connector and said brackets.'

5. An electrical immersion, heater comprising an herinetically sealed covering device having an inner tube, a coil-supporting tube surrounding said inner tube, 'a heating coil wound ou said coil supporting tube and insulated therefrom, a protective fusing device including a fuse wire in circuit with said coil and arranged to be melted by excess of temperature in the adjacent arts, a water-tight electrical connector, an lectrical connections between said heating coil and said connector through said fusing device.

6. In an electrical having a heating coil, means for protection from overheating comprising a bracket made of material as' light as mechanically expedient, and having a threaded hole, a conducting plate resting thereon, but insulated therefrom, a fusing device comprising a shell, a cap on said shell, a illino of insulating cement, a screw embedde in said fillingr and extending beyond the lowest edge of said shell to engage said threaded hole in lsaid bracket, an electrical connection from said bracket to the one end of said heating coil, an electrical connection from said conimmersi on heater,

ducting plate to an external connecting deff vice, whereby, when said screw is threaded in said hole, said shell is seated in electrical Contact with said conducting plate.

7 In an immersion heater, a heating coil, aY protective covering therefor, means for electrically connecting the ends of said heating coil comprising a metal bracket held in position on the tube by the windings of said coil and electrically connected with thc lower end of said coil, a second metal bracket held in 4position on the tube by the windings of said coil and electrically connected with the upper end thereof.

8. In an' ilnmersion heater, a tube, a heating coil wound on .said tube, means for establishing electrical contactwith the lower end of said coil com rising a conducting strip insulated there om and from saidl tube and held in position on the tube by the windings of said coil, an electrical connection at the top of sald strip and electrical contact between the lowerend of vsaid strip` and the lower end of said coil.

In testimon whereof we have set our hands this 14t day of Januar A. D. 1909, in the lpresence of the two su scribed witnesses.

` WILLMM WALLACE Hanscom.

ALBERT LEOPOLD LANGERMAN.

Witnesses:

W. A. Renners, A. H. CAINE.

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