US1614938A - Electrical heating element of the strip type - Google Patents

Electrical heating element of the strip type Download PDF

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US1614938A
US1614938A US697446A US69744624A US1614938A US 1614938 A US1614938 A US 1614938A US 697446 A US697446 A US 697446A US 69744624 A US69744624 A US 69744624A US 1614938 A US1614938 A US 1614938A
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resistor
sheath
electrical heating
heating element
strip type
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US697446A
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Edwin L Wiegand
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Priority claimed from US660294A external-priority patent/US1614330A/en
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/20—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater
    • H05B3/22—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible
    • H05B3/28—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible heating conductor embedded in insulating material
    • H05B3/30—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible heating conductor embedded in insulating material on or between metallic plates

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  • My earlier application relates generally to a noveltype of electrical heating device or element consistinggenerally of a resistor l enveloped in a body or compressed mass of refractory material encased in a sheet metal cover or sheath, the primary object of the invention being to provide an electrical heating device or element affording the maximum output of heat at a given temperature, while providing ample safeguard against a possible breaking down of the insulation between the resistor and the sheath or cover.
  • Such a construction permits very intimate 2 contact between the heat radiating surface of the heating device or element and the object to be heated and afiords unusual diffusion or spreading out of the enveloped resistor and nearness of the resistor-the 2 source of heat--to said object.
  • Such heaters are employed for various purposes. They may be applied to-a late for heating it; or they may be suspen ed from suitable supports for heating space; or they may be applied to the exterior or interior of a vessel for heating the contents thereof; or they may be disposed inside a hollow heating or drying roll.
  • this general type of heater employed the usual resistor wire disposed between sheets of mica, the mica, in turn, being enclosed by and between strips of sheet metal which, form a sort of easing that .is open at its ends. 7
  • the casing being open at.its ends, permitted ingress of moisture and other damagin elements.
  • an elongated, narrow and comparatively thin electrical heating device comprising a resistor element enveloped within a body of refractory, electrical insulating,'heat conducting material that is encased within a sheet metal cover or sheath; to provide, in such a construction, a casing that is completely closed against the ingress of deteriorating agents, as moisture and foreign substances; to provide, in a construction of the foregoing nature, a casing composed of two sheet metal members, one preferably in the form of a channel, and the other a cover between which coverand the web of the channel, the resistor, enveloped in the body of refractory material, is disposed, the edges of the channel being turned over the cover and com pressed to hold the parts firmly together; and also to close the ends of the casing by pressing the extremities of the cover and end extensions of the web of the channel the scope of its intended use, and is so designed and constructed as to expedite manufacture, and insure production at a
  • Fig. l is at plan view and Fig. 2 is a side elevation of my improved strip heater;
  • Fig. 3 is a longitudinal section through one end of the heater on a somewhat enlarged scale;
  • Figs. 4 and 5 are'transverse sections Qn'the same scale as Fig. 3, the heater being shown as flat in the former view and as being transversely curved in the latter view;
  • Figs. 6 and 7 show the strip heater bent to different forms; and
  • Fig. 8 is a fragmentary plan view of a perforated cover that is employed in some instances.
  • 1 denotes the resistor which preferably, but not necessarily consists of a suitable metallic ribbon or flat wire that is preferably bent into serpentine form.
  • This resistor is completely enveloped by a compact homogeneous mass of granular refractory electrical insulating material 2 which not only supports the ribbon at all points due to its intimate contact therewith but also prevents oxidation of the resistor.
  • Each end of the resistor is connected to a terminal 3 which may be of any suitable type but is preferably similar to that disclosed in my co-pending application Serial No. 555,870, filed April 21, 1922.
  • terminals are each provided with insulating washers 4 which prevent contact of the terminals with the sheet metal casing composed of a channel receptacle 5 and a cover plate6 which completely surround the refractory material.
  • the side edges 7 of the receptacle are deflected over the cover plate, as clearly shown in'Figs. 1, 4 and 5, and the ends of the casing beyond the terminals 3 are flattened, as indicated at 8, and are provided with apertures 9 so that the heater may be conveniently supported on a frame or fastened to an object to be heated, If desired the seams formed by the overlapping side edges 7 and the cover plate 6 may be welded, although for ordinary, conditions folding over the edges under high pressure will prove sufiicient.
  • refractory material will be forced into the perforations and thereby serve to bond the refractory material and easing together.
  • a strip heating element of this general character is very thin, light in wei ht, and affords maximum transfer of heat from the resistor to the obiect to be heated.
  • the resistor is complete y enveloped in a compact mass of: refractory material and hence is supported at all points and is completely protected against oxidation.
  • These strip heaters may be longitudinally or laterally bent to various shapes to meet the particular requirements.
  • Fig. 5 I have shown the strip heater bent to assume an arcuate,cross-section while in Figs. 6 and 7' I'have shown the element bent into circular form and U-shape form, respectively.
  • the circular form may be conveniently applied to any cylindrical object as for example a pipe or Water tank, while the U-shape form is suitable for a plication to molds and similar objects.
  • bent into circular form, as in Fig. 6, a bolt 12 may be engaged through apertures 9 for the purpose of retaining the element in position on the object.
  • the resistor element may be enveloped in therefra'ctory insulatin material in accordance with my Patent o. 1,136,076, issued April 20, 1915, entitled Process of producing electrical heating devices, or in accordance with my latent No. 1,398,410 issued November 20, 1921, and entitled Fmbeddin process.
  • an electrical heating element of the strip type as distinguished from electrical stoves, hot plates and tubular heaters, the same comprising a resistor, an elongated, narrow, relatively thin sheet metal sheath made up of a plurality of parts enveloping said resistor and spaced therefrom, and'a mass of granular refractory electrical insulating material of high heat conducting quality filling the space between. the resistor and sheath, the resistor being provided with terminals each accessible through an opening in the sheath.
  • an electrical heating element of the strip type comprising a resistor, an elongated, narrow hen electrical heating element of the strip type comprising a resistor arranged in flat forsheet metal sheath made up sheet metal sheath made up of a plurality of parts enveloping said resistor and spaced therefrom, and an artificially compacted mass of granular refractory electrical insulating material filling the space between the resistor and sheath, the resistor being provided with terminals each accessible through an opening in the sheath.
  • element of the strip type comprising a resistor, an elongated, narrow of a plurality of parts enveloping said resistor and spaced therefrom, and a mass of granular refractory electricalinsulating' material filling the space between the resistor and the sheath,
  • the resistor being provided with terminals each accessible through an opening in the sheath.
  • an'elongated,-narrow sheet metal sheath made up of a plurality of parts enveloping said. resistor and spaced therefrom, and an artificially compacted massof granular refractory electrical insulating material filling the space between the resis-' tor and sheath, the resistor bein provided with terminals each accessible t rough an opening in the sheath.
  • an electrical heating element of the strip type comprising a resistor,-' 'an elongated, narrow seamed sheet metal sheathenveloping said resistor and spaced therefrom, and an artificially compacted mass of granular refractory electrical insulating material, filling the space between the resistor and sheath, the resistor being provided, with terminalseach accessible through an openingin the sheath.
  • platgs and tubular heaters comprising a resistor arranged in flatformation, an elongated, narrow, relatively-thin sheet metal sheath enveloping said resistor and spaced therefrom and being oblong in croSssection, and a inass of granular rev fractory electrical insulating material of high heat conducting quality filling the space between the resistor and the s eath,
  • an electrical heating element of the strip type comprising a resistor, an elongated, narrow sheet metal sheath enveloping said resistor and spaced therefrom, and a mass of granular refractory electrical insulating material fillin the space between the resistor and the provided with'terminals sheat the sheath 'being cldsed at its ends by the pressed together opposed walls of the casing, and the resistor bein provided with terminals each accessible through an opening in the sheath.
  • electrical heating element of the strip type comprising a resistor, an elongated, narrow sheet metalsheath enveloping said resistor and spaced therefrom, and a mass of granular refractory electrical insulating material filling the space between the resistor and the sheath, the resistor being provided with) terminals each accessible through an opening in the sheath, the element having a relatively thin cross section to ermit bending of said elementto various s apes.
  • plates and tubular heaters comprising aresistor, an elongated, narrow, relatively thin sheet metal sheath enveloping said resistor and spaced therefrom, and a mass of. granular refractory electrical insula'ting material of high heat conducting quality filling the space between the resistor and the sheath, the resistor being provided with terminals each accessible through an opening in the sheath, the element having a relatively thin cross section and formed to a desired shape.
  • an electrical heating element of the strip type comprising a resistor, an elongated, narrow seamed sheet metalsheath enveloping said, resistor and spaced therefrom, and an art-ificially compacted mass of granular refracresistor and spaced therefrom, and an artifitory electrical insulating material filling the cially com acted mass of granular refracspace between the resistor and sheath, the tory electrical insulating material filling the resistor having terminals each accessible space betweeh the resistor and sheath,, the 5 through an opening in the wall of the resistor having terminals each accessible sheath intermediate itsends. through an opening in the wall of the 13.
  • an sheath. electrical heating element of thestrip type In testimony whereof, I hereunto aflix my comprising a resistor, an elongated, narrow; signature.

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Description

Jan. 18, 1927.
E. L. WIEGIAND' ELECTRICAL HEATING ELEMENT OF THE STRIP TYPE Original File d August 31v 1923 mut Jan. 18,1927.
UNITED STATES PATENT OFFICE.
EDWIN L. WIEGANILOF DOBMONT BOROUGH, PENNSYLVANIA.
nnnc'rarcnn'nna'rme ELEMENT or, run s'rnrr urn.
Original application fled August 81,
This is a division of my former application, Serial No. 660,294, filed August 31, 1923, and the subject matter of the present case is restricted to a so-called strip heater 6 which is one of the several forms of the invention disclosed in said application.
My earlier application relates generally to a noveltype of electrical heating device or element consistinggenerally of a resistor l enveloped in a body or compressed mass of refractory material encased in a sheet metal cover or sheath, the primary object of the invention being to provide an electrical heating device or element affording the maximum output of heat at a given temperature, while providing ample safeguard against a possible breaking down of the insulation between the resistor and the sheath or cover. Such a construction permits very intimate 2 contact between the heat radiating surface of the heating device or element and the object to be heated and afiords unusual diffusion or spreading out of the enveloped resistor and nearness of the resistor-the 2 source of heat--to said object. Numerous other advantages arising from such a construction are set forth in my former application and it is deemed unnecessary to repeat them here, and in the earlier case their im- 3 portance is emphasized by a comparison of my improved evice or element with rior forms of electrical heating devices 0 the same general class. 1 As above stated, the present case has to do particularly with strip heaters which have acquired a distinct place in the art.
Such heaters are employed for various purposes. They may be applied to-a late for heating it; or they may be suspen ed from suitable supports for heating space; or they may be applied to the exterior or interior of a vessel for heating the contents thereof; or they may be disposed inside a hollow heating or drying roll. In the past, the more common forms of this general type of heater employed the usual resistor wire disposed between sheets of mica, the mica, in turn, being enclosed by and between strips of sheet metal which, form a sort of easing that .is open at its ends. 7
An advantage which my improved strip heater possesses over these earlier forms is thatit maybe readily bent .to conform to object'sp fjid-ifi'erent shapes to which it may 1928, Serial No. 66 0394. Divided and this application filed larch 7, 1824. Serial No. 697,446.
and resistor which results in a breaking up and displacement of the mica sheets or lay-' ers and the resistor and an egrees of some of the disintegrated mica through the open ends of the casing. Furthermore, the casing, being open at.its ends, permitted ingress of moisture and other damagin elements.
Among the several objects 0 my present invention are to provide an elongated, narrow and comparatively thin electrical heating device comprising a resistor element enveloped within a body of refractory, electrical insulating,'heat conducting material that is encased within a sheet metal cover or sheath; to provide, in such a construction, a casing that is completely closed against the ingress of deteriorating agents, as moisture and foreign substances; to provide, in a construction of the foregoing nature, a casing composed of two sheet metal members, one preferably in the form of a channel, and the other a cover between which coverand the web of the channel, the resistor, enveloped in the body of refractory material, is disposed, the edges of the channel being turned over the cover and com pressed to hold the parts firmly together; and also to close the ends of the casing by pressing the extremities of the cover and end extensions of the web of the channel the scope of its intended use, and is so designed and constructed as to expedite manufacture, and insure production at a low cost.
The foregoing objects, with others hereinafter appearing, are attained in the embodiment of the invention illustrated in the accompanying drawing wherein Fig. l is at plan view and Fig. 2 is a side elevation of my improved strip heater; Fig. 3 is a longitudinal section through one end of the heater on a somewhat enlarged scale; Figs. 4 and 5 are'transverse sections Qn'the same scale as Fig. 3, the heater being shown as flat in the former view and as being transversely curved in the latter view; Figs. 6 and 7 show the strip heater bent to different forms; and Fig. 8 is a fragmentary plan view of a perforated cover that is employed in some instances.
Describing the construction by the use of reference numerals, 1 denotes the resistor which preferably, but not necessarily consists of a suitable metallic ribbon or flat wire that is preferably bent into serpentine form. This resistor is completely enveloped by a compact homogeneous mass of granular refractory electrical insulating material 2 which not only supports the ribbon at all points due to its intimate contact therewith but also prevents oxidation of the resistor. Each end of the resistor is connected to a terminal 3 which may be of any suitable type but is preferably similar to that disclosed in my co-pending application Serial No. 555,870, filed April 21, 1922. These terminals are each provided with insulating washers 4 which prevent contact of the terminals with the sheet metal casing composed of a channel receptacle 5 and a cover plate6 which completely surround the refractory material. The side edges 7 of the receptacle are deflected over the cover plate, as clearly shown in'Figs. 1, 4 and 5, and the ends of the casing beyond the terminals 3 are flattened, as indicated at 8, and are provided with apertures 9 so that the heater may be conveniently supported on a frame or fastened to an object to be heated, If desired the seams formed by the overlapping side edges 7 and the cover plate 6 may be welded, although for ordinary, conditions folding over the edges under high pressure will prove sufiicient.
In some instan ces where it is unnecessary to provide a tight seal for the insulating material, I perforate a portion of the metal casing as for example the cover plate 11, as
shown in Fig. 8. During the folding and pressing of the side edges of the casing, the
refractory material will be forced into the perforations and thereby serve to bond the refractory material and easing together.
A strip heating element of this general character is very thin, light in wei ht, and affords maximum transfer of heat from the resistor to the obiect to be heated. The resistor is complete y enveloped in a compact mass of: refractory material and hence is supported at all points and is completely protected against oxidation. These strip heaters may be longitudinally or laterally bent to various shapes to meet the particular requirements.
In Fig. 5 I have shown the strip heater bent to assume an arcuate,cross-section while in Figs. 6 and 7' I'have shown the element bent into circular form and U-shape form, respectively. The circular form may be conveniently applied to any cylindrical object as for example a pipe or Water tank, while the U-shape form is suitable for a plication to molds and similar objects. bent into circular form, as in Fig. 6, a bolt 12 may be engaged through apertures 9 for the purpose of retaining the element in position on the object.
While, so far as the present invention is concerned, I do not limit myself to any particular kind of refractory insulating material, one kind found especially suitable for the purpose is composed of magnesium or aluminum oxide or zirconium silicate, either individually where possible or a compound of them, together when desirable with a binding material such as clay, to give the necessary plasticity during fabrication and to effect homogeneity in the final product." Neither do I limit myself in the broad analysis of the invention to a sheath or cover constructed in the manner illustrated, as obviously the same might take various forms amlQr-onstructions without departing from the spirit of the invention.
The resistor element may be enveloped in therefra'ctory insulatin material in accordance with my Patent o. 1,136,076, issued April 20, 1915, entitled Process of producing electrical heating devices, or in accordance with my latent No. 1,398,410 issued November 20, 1921, and entitled Fmbeddin process.
IF aving thus described my invention, what I claim 1s:
1. As a new article of manufacture, an electrical heating element of the strip type, as distinguished from electrical stoves, hot plates and tubular heaters, the same comprising a resistor, an elongated, narrow, relatively thin sheet metal sheath made up of a plurality of parts enveloping said resistor and spaced therefrom, and'a mass of granular refractory electrical insulating material of high heat conducting quality filling the space between. the resistor and sheath, the resistor being provided with terminals each accessible through an opening in the sheath. v
2. As a new article of manufacture, an electrical heating element of the strip type comprising a resistor, an elongated, narrow hen electrical heating element of the strip type comprising a resistor arranged in flat forsheet metal sheath made up sheet metal sheath made up of a plurality of parts enveloping said resistor and spaced therefrom, and an artificially compacted mass of granular refractory electrical insulating material filling the space between the resistor and sheath, the resistor being provided with terminals each accessible through an opening in the sheath.
3. As a new article of manufacture, any
electrical heating, element of the strip type comprising a resistor, an elongated, narrow of a plurality of parts enveloping said resistor and spaced therefrom, and a mass of granular refractory electricalinsulating' material filling the space between the resistor and the sheath,
the ,entire as:en1bly being in a highly compacted state, the resistor being provided with terminals each accessible through an opening in the sheath. I
.4. As a new article of manufacture, an
mation, an'elongated,-narrow sheet metal sheath made up of a plurality of parts enveloping said. resistor and spaced therefrom, and an artificially compacted massof granular refractory electrical insulating material filling the space between the resis-' tor and sheath, the resistor bein provided with terminals each accessible t rough an opening in the sheath.
- 5. As a new article of manufacture, an
as distin electricagltileating element of the strip type,
ished from electrical stoves, hot
' plates and tubular heatersgthe same comprising a resistor, an elongated, narrow, relatively thin, seamed sheet metal sheath enveloping said resistor and spaced therefrom,
and a mass of granular refractory electrical insulating material of high heat conducting quality filling the space between the resistor and sheath, the resistor being provided with terminals each accessible through an opening in the sheath. 7
6. As a new article of manufacture, an electrical heating element of the strip type comprising a resistor,-' 'an elongated, narrow seamed sheet metal sheathenveloping said resistor and spaced therefrom, and an artificially compacted mass of granular refractory electrical insulating material, filling the space between the resistor and sheath, the resistor being provided, with terminalseach accessible through an openingin the sheath.
7. As a new article of manufacture, an electrical heating element of the strip type,
as distinguished from electrical stoves, hot
platgs and tubular heaters, the same comprising a resistor arranged in flatformation, an elongated, narrow, relatively-thin sheet metal sheath enveloping said resistor and spaced therefrom and being oblong in croSssection, and a inass of granular rev fractory electrical insulating material of high heat conducting quality filling the space between the resistor and the s eath,
sulating material of hi h heat conducting quality filling the space tween the resistor and the sheath, the sheath consisting of two main parts closely embracing and envfeloping said mass of insulating material, and the resistor bein provided with terminals each accessible t roughan opening in the sheath. 7
9. 'As a new article-of manufacture, an electrical heating element of the strip type comprising a resistor, an elongated, narrow sheet metal sheath enveloping said resistor and spaced therefrom, and a mass of granular refractory electrical insulating material fillin the space between the resistor and the provided with'terminals sheat the sheath 'being cldsed at its ends by the pressed together opposed walls of the casing, and the resistor bein provided with terminals each accessible through an opening in the sheath.
10.;Asa new article of manufacture, an
electrical heating element of the strip type comprising a resistor, an elongated, narrow sheet metalsheath enveloping said resistor and spaced therefrom, and a mass of granular refractory electrical insulating material filling the space between the resistor and the sheath, the resistor being provided with) terminals each accessible through an opening in the sheath, the element having a relatively thin cross section to ermit bending of said elementto various s apes.
11. As a new article of manufacture, an
electrical heating element of the striptype,
as distinguished .from electrical stoves, hot
plates and tubular heaters, the same comprising aresistor, an elongated, narrow, relatively thin sheet metal sheath enveloping said resistor and spaced therefrom, and a mass of. granular refractory electrical insula'ting material of high heat conducting quality filling the space between the resistor and the sheath, the resistor being provided with terminals each accessible through an opening in the sheath, the element having a relatively thin cross section and formed to a desired shape. r Y
12. As .a new article of manufacture, an electrical heating element of the strip type comprising a resistor, an elongated, narrow seamed sheet metalsheath enveloping said, resistor and spaced therefrom, and an art-ificially compacted mass of granular refracresistor and spaced therefrom, and an artifitory electrical insulating material filling the cially com acted mass of granular refracspace between the resistor and sheath, the tory electrical insulating material filling the resistor having terminals each accessible space betweeh the resistor and sheath,, the 5 through an opening in the wall of the resistor having terminals each accessible sheath intermediate itsends. through an opening in the wall of the 13. As a new article of manufacture, an sheath. electrical heating element of thestrip type In testimony whereof, I hereunto aflix my comprising a resistor, an elongated, narrow; signature.
formed sheet metal sheath enveloping 'sai EDWIN L. WIEGAND.
US697446A 1923-08-31 1924-03-07 Electrical heating element of the strip type Expired - Lifetime US1614938A (en)

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US660294A US1614330A (en) 1923-08-31 1923-08-31 Electrical heating element
US697446A US1614938A (en) 1923-08-31 1924-03-07 Electrical heating element of the strip type

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2875312A (en) * 1956-09-27 1959-02-24 Thermel Inc Heating assembly and method of production thereof
WO2003007313A3 (en) * 2001-07-03 2003-08-21 Cci Thermal Technologies Inc Corrugated metal ribbon heating element
US20080035704A1 (en) * 2006-04-26 2008-02-14 Panasonic Ev Energy Co., Ltd. Thermowelding apparatus and method for manufacturing battery module

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2875312A (en) * 1956-09-27 1959-02-24 Thermel Inc Heating assembly and method of production thereof
WO2003007313A3 (en) * 2001-07-03 2003-08-21 Cci Thermal Technologies Inc Corrugated metal ribbon heating element
US20080035704A1 (en) * 2006-04-26 2008-02-14 Panasonic Ev Energy Co., Ltd. Thermowelding apparatus and method for manufacturing battery module
US7712648B2 (en) * 2006-04-26 2010-05-11 Panasonic Ev Energy Co., Ltd. Thermowelding apparatus and method for manufacturing battery module

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