US1643673A

US1643673A - Electric-heating element

Info

Publication number: US1643673A
Application number: US113120A
Authority: US
Inventors: Warren C Merrill
Original assignee: Individual
Current assignee: Individual
Priority date: 1926-06-02
Filing date: 1926-06-02
Publication date: 1927-09-27
Anticipated expiration: 1944-09-27

Description

ep 19 7 w. c. MERRILL ELECTRIC HEATING ELEMENT Filed June 2. 1926 INVENTOR.

BY RREN c. MERRILL.

WMUQ /S A TORNEY.

Patented Sept. 27, 1927.-

UNITED STATES WARREN C. MERRILL, F ALAMEDA, CALIFORNIA,

ELECTRIC-HEATING ELEMENT.

Application filed June 2, 1926. Serial No. 113,120.

This invention relates to electric heating elements as used principally in water heaters and the objects of the invention are to provide a simple more'lasting construction of such elements as well as one having greater eificiency for the heating of fluids than prior devices of this kind.

My element is preferably of the plug type adapted for insertion into the casing and Water space of an electric water heater and is illustrated in the following drawings in which:

Figure 1 is an outside view of the complete device ready for screwing into the heater.

Flgure 2 is a View similar to the view of Figure l but shown partly in section.

Fi ure 3 is an enlargedcross section of the evice taken along the line 3-3 of Figare 2, while Figure 4 is a similarly enlarged longitudinal section taken at any point through the windings of the device.

In further detail the device comprises a screw plug or head 1, adapted for securing in an opening of a heater casing by means of a pipe thread 2 or otherwise, while extending from the plug is an elongated resistance assemblage enclosed in a tube 3.

This tube 3 isg'preferably of metal and tapered ofi at an angle at both ends as indicated, with one of the tapered ends extending into a mating recess formed in the" head 1, and there firmly secured in place by 1 any desired means, tho shown to be welded or soldered as at 4.

With the tube angularly cut and mounted as described it will be observed that a passage way indicated by the arrows is open at all times from one end to the other for free circulation of any fluid into which the element might be inserted.

Within the tube 3 is spaced a smaller tube.

5 preferably of polygonal cross section as indicated in Figure 3 with from three to an number of sides, and around which po ygonal tube a spiral of resistance wire 6 is wrapped.

This wire 6 is preferably of flat section as indicated clearly in Figure 4 and arranged in several layers insulated from the two

tubes

3 and 5 by means of several. layers of sheet insulation 7, preferably of the mica variety lying between the wires and the

respective tubes

3 and 5 as well as betweenany several layers of the resistance coils as denoted at 7'.

wire are wound over. these other layers of insulation, all follow the same angle and spacing but the coils have their windings staggered so as to bring the coils of one wrapping directly between the spacings of the next layer of wires.

By theabove arrangement of insulation in sheets and staggered wires the inner sheets of insulation 7 become slightly undulateddue to the pressure thereagainstof the v staggered outer coils which aids in preserving the coils from shifting laterally through the constant expansion and contraction, though even with a sin 1e layer of resistance wire the tendency of WlIGS to shift is o'vercome due tothe use of the polygonal J lnner .tube 5 around which the flat wlre is wrapped, for the wire firmly contacting the corners of the mica wrapped tube is quite free adjacent all flat faces of the tube and where the expansion takes place, without affecting the seating of, the wire on the high points of the tube.

The tube 5 after being completely wrapped as described is fitted snugly within the outer tube 3 and the open ends sealed by any desired means, a satisfactory method of effecting this being to first push some asbestos packing in the space between the tubes as indicated at 8 and then filling the remaining outer space with solder as at 9.

At the head end of thetube the terminal ends 10 and 10' of the wire are respectively attached to suitable binding posts or screws 11 and 11' mounted in an insulating block 12 secured to the head 1 ,by screws or the like as indicated.

In considering my electric heating element as above disclosed, it will be'seen that it may be screwed into openings in a water compartment and that owing to the peculiar construction it will not suffer disarrangement through long use, and that upon heating up it causes a constant circulation of water flowing from the plug end to the outer end the larger efiective opening at the outer en insuring a current, and the angular out thereof overcoming interference of the water current from other elements projecting into the heater below it.

I claim:

-1. An electric heating element comprising a head having a resistance element of tubular construction extending therefrom unsupported at its outer end arranged to carry a flow of liquid through its tubular body from the head end for discharge at the outer end and said outer end being cut ofi at a bevel to the axis of the tubular body.

l2. An electric heating element for a fluid heater comprising an attaching head and a resistance coil enclosed in a tube extending from and secured at one end only to said head, said tube being beveled at the end and seated in a pocket formed in the head.

3. In an electrical heating element of the character described, a pair of tubes spaced one Within the other, layers of resistance wire wrapped aroundthe inner tube and spaced therefrom and from the outer tube by insulation, said resistance wire forming a plurality of spirals with coils spaced and in staggered relation separated by flexible sheet insulation positioned between the coils indented by the wrapping of the coils thereon.

4. In an electrical heating element of the character described, a pair of tubes spaced one within theother, layers of resistance wire wrapped around the inner tube and spaced therefrom and from the outer tube by flexible sheet insulation said inner tube being of polygonal cross section.

5. In an electrical heating element of the character described, a pair of tubes spaced one within the other, layers of resistance wire wrapped around the inner tube and spaced therefrom and from the outer tube by flexible sheet insulation said inner tube being of polygonal cross section and said outer tube being of round cross section.

6. An electric tubular heating element adapted for insertion through the side of a Water container .in horizontal extension therein and provided with a downwardly directed water inlet at one end to receive water into said element, and a discharge opening for said water at a point remote from said inlet when so positioned and whereby a current of water is caused to flow through the length of said element upon heating the same.

7. An electric tubular heating element adapted for insertion through the side of a water container in horizontal extension therein and provided with a downwardly directed water inlet at the end adjacent the container and an upwardly directed water discharge outlet when so positioned and whereby a current of water is caused to flow through the length of said element upon heating the same.

WARREN C. MERRILL.