US3345597A - Electric heating resistors - Google Patents
Electric heating resistors Download PDFInfo
- Publication number
- US3345597A US3345597A US391555A US39155564A US3345597A US 3345597 A US3345597 A US 3345597A US 391555 A US391555 A US 391555A US 39155564 A US39155564 A US 39155564A US 3345597 A US3345597 A US 3345597A
- Authority
- US
- United States
- Prior art keywords
- resistor element
- rod
- support
- resistor
- helical
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000005485 electric heating Methods 0.000 title description 4
- 238000010438 heat treatment Methods 0.000 claims description 5
- YXTPWUNVHCYOSP-UHFFFAOYSA-N bis($l^{2}-silanylidene)molybdenum Chemical compound [Si]=[Mo]=[Si] YXTPWUNVHCYOSP-UHFFFAOYSA-N 0.000 claims description 4
- 229910021343 molybdenum disilicide Inorganic materials 0.000 claims description 3
- 239000000463 material Substances 0.000 description 9
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 4
- 229910010271 silicon carbide Inorganic materials 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 2
- 229910052863 mullite Inorganic materials 0.000 description 2
- 229910021332 silicide Inorganic materials 0.000 description 2
- 240000005369 Alstonia scholaris Species 0.000 description 1
- 229910016006 MoSi Inorganic materials 0.000 description 1
- -1 MoSi and Chemical compound 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 229910021344 molybdenum silicide Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- FVBUAEGBCNSCDD-UHFFFAOYSA-N silicide(4-) Chemical compound [Si-4] FVBUAEGBCNSCDD-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- 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
- H05B3/10—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
- H05B3/12—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
- H05B3/14—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material the material being non-metallic
- H05B3/148—Silicon, e.g. silicon carbide, magnesium silicide, heating transistors or diodes
-
- 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
- H05B3/10—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
- H05B3/12—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
- H05B3/14—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material the material being non-metallic
-
- 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
- H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
- H05B2203/018—Heaters using heating elements comprising mosi2
Definitions
- the present invention relates to electric heating resistors manufactured in a powder-metallurgical way and composed of a conductive tubular resistor element and a support therefor.
- Said element consists substantially of molybdenum silicide, particularly MoSi and, if desired, also of one or more other heat resisting silicides and/ or oxides, such as SiO and is slotted along a helix to ob tain a helical resistor portion and thus increase the electrical resistivity thereof so as to make said portion to constitute an incandescent zone.
- Said support is constituted by a heat resisting through-going elongated body or rod inserted into said element. Those portions of the resistor element which are not cut up have a lower resistivity and serve as relatively cold terminals.
- Suitable materials for the conductive resistor element are disclosed in the United States Patents Nos. 2,992,959, 2,993,111, 3,027,330, 3,027,331, 3,027,332 and 3,036,017.
- Suitable materials for the support are described, for instance, in the French Patent No. 1,320,277. Such materials should have a sufficiently high content of silicon carbide to guarantee an adequate stiffness of the support at the operating temperature.
- the resistor element there may also be included a certain content of SiC which should be so low or at most 20% by volume in order to make sure that the electric conductivity at room temperature is not reduced too much.
- a certain content of SiC which should be so low or at most 20% by volume in order to make sure that the electric conductivity at room temperature is not reduced too much.
- Such a material becomes soft at high temperature, such as up to 1600 C., and a resistor element made of this material can thus not be mounted in a horisontal position. It has been proposed to support such a tubular resistance element upon a through-going interior silicon carbide rod which has a silicon carbide content exceeding about 40% by volume.
- the carbide particles are recrystallized and constitute a skeleton the cavities of which are impregnated with a silicide. Such a rod will retain its stiffness also at very high temperatures.
- the present invention has, inter alia, for its purpose to avoid this inconvenience. This is obtained by interposing an intermediate layer between the resistor element and the support, said layer being electrically insulating and forming a non-adhesive intermediary between the surfaces.
- the quartz glass film does not adhere to said intermediate layer it this is made of mullite.
- the resistor element and the support obtain a certain degree of freedom of movement in relation to one another, and are thus relieved Claims from thermal tensions.
- This freedom of movement is of particular importance in this case in which the central zone is weakened by the helical slot.
- FIG. 1 being a lateral view
- FIG. 2 an end view.
- the incandescent zone of the resistor element 1 is constituted by the central portion thereof and is provided with a helical slot 2 so that the electrical resistivity in this zone is several times higher than in the terminal zones.
- the support extends in the shape of a rod 3 and between this rod and the element there is an intermediate layer 4 interposed.
- This intermediate layer may consist of material which is flame sprayed directly on the support rod. It may also be constituted by one or more tube sections thrust on the support rod 3.
- a rod-shaped electrical heating resistor composed of a generally cylindrical resistor element consisting essentially of molybdenum disilicide, said cylindrical resistor element containing a helical slot in the central portion thereof to form a helical resistor element and thereby increase said elements electrical resistance in said central portion, said helical resistor element being selfsupporting at normal room temperature and being deformable by the influence of its own weight when unsupported during operation at high temperatures between 1400 C. and 1800" C.; a rod-shaped heat-resisting support inserted into said cylindrical resistor element to prevent said elements high temperature deformation, and an intermediate layer of insulating material positioned between the supporting rod and the resistor element, the outside surface of said intermediate layer being in contact with the inner surface of said cylindrical resistor element.
- Resistor according to claim 1 in which the intermediate layer consists of a film flame sprayed directly on to the support.
- a rod-shaped electrical heating resistor composed of a generally cylindrical resistor element consisting essentially of molybdenum disilicide, said cylindrical resistor element containing a helical slot in the central portion thereof to form a helical resistor element and thereby increase said elements electrical resistance in said central portion, said helical resistor element being selfsupporting at normal room temperature and being deformable by the influence of its own weight when unsupported during operation at high temperatures between 1400 C. and 1800 C.; a rod-shaped heat-resisting support inserted into said cylindrical resistor element, said rod-shaped support being composed of insulative material.
Landscapes
- Resistance Heating (AREA)
Description
1967 N76. SCHREWELIUS ET AL 3,345,597
ELECTRIC HEATING RESISTORS Filed Aug. 24, 1964 Fig.1
i: {1 1: I 1 I II 1 H H r :1 N Hi H {I ll ,1
| I I J11 I: s:
ll H
Fig.2
INVENTOR ATTORNEY United States' Patent 3,345,597 ELECTRIC HEATING RESISTORS Nils Gustav Schrewelius and Clas Bengt 0. Magnusson, Hallstahammar, Sweden, assignors to Aktiebolaget ganhal, Hallstahammar, Sweden, a corporation of we en Filed Aug. 24, 1964, Ser. No. 391,555 priority, application Sweden, Aug. 27, 1963,
9,321/63 7 Claims. (Cl. 338-302) The present invention relates to electric heating resistors manufactured in a powder-metallurgical way and composed of a conductive tubular resistor element and a support therefor. Said element consists substantially of molybdenum silicide, particularly MoSi and, if desired, also of one or more other heat resisting silicides and/ or oxides, such as SiO and is slotted along a helix to ob tain a helical resistor portion and thus increase the electrical resistivity thereof so as to make said portion to constitute an incandescent zone. Said support is constituted by a heat resisting through-going elongated body or rod inserted into said element. Those portions of the resistor element which are not cut up have a lower resistivity and serve as relatively cold terminals.
Suitable materials for the conductive resistor element are disclosed in the United States Patents Nos. 2,992,959, 2,993,111, 3,027,330, 3,027,331, 3,027,332 and 3,036,017.
Suitable materials for the support are described, for instance, in the French Patent No. 1,320,277. Such materials should have a sufficiently high content of silicon carbide to guarantee an adequate stiffness of the support at the operating temperature.
In the resistor element there may also be included a certain content of SiC which should be so low or at most 20% by volume in order to make sure that the electric conductivity at room temperature is not reduced too much. Such a material becomes soft at high temperature, such as up to 1600 C., and a resistor element made of this material can thus not be mounted in a horisontal position. It has been proposed to support such a tubular resistance element upon a through-going interior silicon carbide rod which has a silicon carbide content exceeding about 40% by volume. The carbide particles are recrystallized and constitute a skeleton the cavities of which are impregnated with a silicide. Such a rod will retain its stiffness also at very high temperatures. On the inside of the resistor element and on the outside of the support there will then be formed a quartz glass film which at high temperature cements together the resistor element and the support. As the coeflicient of thermal expansion is quite different in the resistor element and in the support this will produce mechanical tensions between the resistor element and the support body resulting in ruptures in the material when the temperature changes. 7
The present invention has, inter alia, for its purpose to avoid this inconvenience. This is obtained by interposing an intermediate layer between the resistor element and the support, said layer being electrically insulating and forming a non-adhesive intermediary between the surfaces.
Surprisingly, it has been found that the quartz glass film does not adhere to said intermediate layer it this is made of mullite. In this case the resistor element and the support obtain a certain degree of freedom of movement in relation to one another, and are thus relieved Claims from thermal tensions. This freedom of movement is of particular importance in this case in which the central zone is weakened by the helical slot.
On the accompanying drawing there is shown an embodiment of the invention, FIG. 1 being a lateral view and FIG. 2 an end view.
The incandescent zone of the resistor element 1 is constituted by the central portion thereof and is provided with a helical slot 2 so that the electrical resistivity in this zone is several times higher than in the terminal zones. Along the central axis of the element the support extends in the shape of a rod 3 and between this rod and the element there is an intermediate layer 4 interposed. This intermediate layer may consist of material which is flame sprayed directly on the support rod. It may also be constituted by one or more tube sections thrust on the support rod 3.
What we claim is:
1. A rod-shaped electrical heating resistor composed of a generally cylindrical resistor element consisting essentially of molybdenum disilicide, said cylindrical resistor element containing a helical slot in the central portion thereof to form a helical resistor element and thereby increase said elements electrical resistance in said central portion, said helical resistor element being selfsupporting at normal room temperature and being deformable by the influence of its own weight when unsupported during operation at high temperatures between 1400 C. and 1800" C.; a rod-shaped heat-resisting support inserted into said cylindrical resistor element to prevent said elements high temperature deformation, and an intermediate layer of insulating material positioned between the supporting rod and the resistor element, the outside surface of said intermediate layer being in contact with the inner surface of said cylindrical resistor element.
2. An electrical heating resistor as described in claim 1, wherein the outer surface of said intermediate material is in non-adhesive cont act with the inner surface of the cylindrical resistor element.
3. The resistor of claim 1 in which said intermediate layer is made of mullite.
4. A resistor as claimed in claim 1 in which the intermediate layer is made in the form of one or more tubes thrust on to the support body.
5. Resistor according to claim 1 in which the intermediate layer consists of a film flame sprayed directly on to the support.
6. A rod-shaped electrical heating resistor composed of a generally cylindrical resistor element consisting essentially of molybdenum disilicide, said cylindrical resistor element containing a helical slot in the central portion thereof to form a helical resistor element and thereby increase said elements electrical resistance in said central portion, said helical resistor element being selfsupporting at normal room temperature and being deformable by the influence of its own weight when unsupported during operation at high temperatures between 1400 C. and 1800 C.; a rod-shaped heat-resisting support inserted into said cylindrical resistor element, said rod-shaped support being composed of insulative material.
7. An electrical heating resistor as described in claim 6, wherein the outer surface of the support rod is in nonadhesive contact wit h the ir lner surface of the cylindrical 7 2,622,304 12/1952 Coffer 252--518 resistor element.-- 1 1 i 3,063,100 11/1962 K-Ohring 338226 X References Cited 3,254,320 5/ 1966 Hill et a1. 338-331 UNITED STATES PATENTS 5 RICHARD M. WOOD, Primary Examiner. 1,551,766 9/1925 North-Ind 1325 X 2,298,791 '7/1942 Loftis et a1. 338-314 X SMITH Assistant Examiner-
Claims (1)
1. A ROD-SHAPED ELECTRICAL HEATING RESISTOR COMPOSED OF A GENERALLY CYLINDRICAL RESISTOR ELEMENT CONSISTING ESSENTIALLY OF MOLYBDENUM DISILICIDE, SAID CYLINDRICAL RESISTOR ELEMENT CONTAINING A HELICAL SLOT IN THE CENTRAL PORTION THEREOF TO FORM A HELICAL RESISTOR ELEMENT AND THEREBY INCREASE SAID ELEMENT''S ELECTRICAL RESISTANCE IN SAID CENTRAL PORTION, SAID HELICAL RESISTOR ELEMENT BEING SELFSUPPORTING AT NORMAL ROOM TEMPERATURE AND BEING DEFORMABLE BY THE INFLUENCE OF ITS OWN WEIGHT WHEN UNSUPPORTED DURING OPERATION AT HIGH TEMPERATURES BETWEEN 1400*C. AND 1800*C.; A ROD-SHAPED HEAT-RESIST-
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE932163 | 1963-08-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3345597A true US3345597A (en) | 1967-10-03 |
Family
ID=20276393
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US391555A Expired - Lifetime US3345597A (en) | 1963-08-27 | 1964-08-24 | Electric heating resistors |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US3345597A (en) |
| GB (1) | GB1075073A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3518351A (en) * | 1968-12-16 | 1970-06-30 | Carborundum Co | Heating element |
| US3800057A (en) * | 1972-07-24 | 1974-03-26 | Preussag Ag | Electrically heated furnace utilizing ceramic heating elements |
| US3912908A (en) * | 1974-11-12 | 1975-10-14 | Us Energy | Electric cartridge-type heater for producing a given non-uniform axial power distribution |
| US4272639A (en) * | 1979-08-01 | 1981-06-09 | Btu Engineering Corporation | Helically wound heater |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2279855A (en) * | 1993-07-02 | 1995-01-11 | Zortech Int | Resistance tubular heating wire |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1551766A (en) * | 1922-09-30 | 1925-09-01 | Ajax Electrothermic Corp | Resistor and high-frequency furnace |
| US2298791A (en) * | 1938-05-14 | 1942-10-13 | Standard Oil Dev Co | Solvent treating of mineral oils |
| US2622304A (en) * | 1950-10-02 | 1952-12-23 | Climax Molybdenum Co | Refractory |
| US3063100A (en) * | 1959-09-21 | 1962-11-13 | Wilbur M Kohring | Process for making resistors |
| US3254320A (en) * | 1963-08-15 | 1966-05-31 | Babcock & Wilcox Co | Electric heaters |
-
1964
- 1964-08-24 US US391555A patent/US3345597A/en not_active Expired - Lifetime
- 1964-08-27 GB GB35218/64A patent/GB1075073A/en not_active Expired
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1551766A (en) * | 1922-09-30 | 1925-09-01 | Ajax Electrothermic Corp | Resistor and high-frequency furnace |
| US2298791A (en) * | 1938-05-14 | 1942-10-13 | Standard Oil Dev Co | Solvent treating of mineral oils |
| US2622304A (en) * | 1950-10-02 | 1952-12-23 | Climax Molybdenum Co | Refractory |
| US3063100A (en) * | 1959-09-21 | 1962-11-13 | Wilbur M Kohring | Process for making resistors |
| US3254320A (en) * | 1963-08-15 | 1966-05-31 | Babcock & Wilcox Co | Electric heaters |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3518351A (en) * | 1968-12-16 | 1970-06-30 | Carborundum Co | Heating element |
| US3800057A (en) * | 1972-07-24 | 1974-03-26 | Preussag Ag | Electrically heated furnace utilizing ceramic heating elements |
| US3912908A (en) * | 1974-11-12 | 1975-10-14 | Us Energy | Electric cartridge-type heater for producing a given non-uniform axial power distribution |
| US4272639A (en) * | 1979-08-01 | 1981-06-09 | Btu Engineering Corporation | Helically wound heater |
Also Published As
| Publication number | Publication date |
|---|---|
| GB1075073A (en) | 1967-07-12 |
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