CN1187284A - Electrical heating elements - Google Patents

Electrical heating elements Download PDF

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Publication number
CN1187284A
CN1187284A CN 96194586 CN96194586A CN1187284A CN 1187284 A CN1187284 A CN 1187284A CN 96194586 CN96194586 CN 96194586 CN 96194586 A CN96194586 A CN 96194586A CN 1187284 A CN1187284 A CN 1187284A
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coating
oxide skin
conductive
resistive
contact zone
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CN 96194586
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杰夫里·波德曼
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BOARDMAN PRODUCT DEVELOPMENT Ltd
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BOARDMAN PRODUCT DEVELOPMENT Ltd
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Priority to CN 96194586 priority Critical patent/CN1187284A/en
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Abstract

An electrically resistive heating element for liquids and a method of fabricating same. The heating element comprises a substrate (10) formed of an electrically insulating material or formed of an electrically conductive material provided with an electrically insulating coating, whereby in both cases the substrate (10) presents an electrically non-conductive surface on at least one side. First (14a) and second (14b) laterally spaced contact areas are disposed over the electrically non-conductive surface and a thermally sprayed resistive oxide layer (16) is applied to the electrically non-conductive surface and disposed over or under parts of the contact areas (14a, 14b) to enable an electric current to be passed through the resistive oxide layer (16) via these first and second contact areas.

Description

Electrical heating elements
The present invention relates to electrical heating elements, especially relate to stratie, this element is mainly used in the home appliances that liquid is heated for preparation food, for example kettle, heating tank, coffee pot and similar appliances, this element belongs to the sort of type that does not take the volume of wanting heated liquid.
The conventional electrical heating elements that is used for liquid is divided into two big classes.
The first kind is armouring (sheathed) element, and these elements comprise a metal tube, is provided with the spiral yarn shaped element of routine along the longitudinal axis of this metal tube, and adopts oxide as the dielectric between metal tube and the helical element (electric insulation) parts.These armouring elements form the annular or the spirality of certain form usually, and are positioned to be used for the bottom of the container of heating liquid.They just enter in the volume of wanting heated liquid like this.
The element of a kind of form in back is generally used for only heating a kind of liquid, and water always almost because its convoluted shape makes the vestige that is difficult to clean and removes one type liquid fully, is used to heat the words of second kind of liquid if desired.
In addition, need an outer metal armouring with spiral yarn shaped element and fluid separation applications, and needing a kind of dielectric oxide packing material separates metal armouring with element, the result, this class component has bigger quality and less surface area, and these two kinds of characteristics reduce in conjunction with the operating efficiency that causes this class component heating liquid.
The second class known elements comprises the element that those are made up of flat board, and the dull and stereotyped end that constitutes heating container, heat reaches liquid by flat board from element.This class component does not enter in the volume of wanting heated liquid.
This second class component can be divided into two types, and specifically, first type is to adopt the conventional armouring element that is fixed to a dull and stereotyped back side simply, and this flat board plays the effect of heating panel, and second type can be referred to as the thick-film resistor heating element.
The conventional method that forms thick film element is to adopt a metallic substrates, applies dielectric coating on the surface of this substrate, normally glaze.Adopt screen printing technique, in the mode of the element configurations that comprises one or more printed circuit strip conductor, form sediment on the surface of a coating (sink) amasss printing ink of being made up of the mixture of solvent and metal and/or metal oxide.Folder is thereafter by flame heat, to remove solvent and to make metal and/or the resistance of oxide (property) particles fuse.Last dielectric coating of coating on the component structure of silk screen printing then, glaze normally, this coating plays the effect of protective layer.
Although armouring element that these are conventional and silk screen printing thick film element can satisfy the requirement of heating liquid fully, there is the shortcoming of multiple structure and work aspect in they, and wherein the part shortcoming is as described below.
Because need to adopt the oxide dielectric packing material in the armouring element, the ressitance spiral that is used to produce thermal effect need be operated in and make under the temperature of the required temperature of liquid boiling far away surpassing.As a result, if work under the situation that the liquid that does not have q.s centers on, this class component is very easy to overheated and burns out.In addition, its higher thermal mass is harmful to its operating efficiency, because the major part of the heat that produces when initial is directly used in the temperature that promotes dielectric metal oxide and metal armouring, rather than enters liquid.This has reduced the temperature rise speed of liquid.
In order in disk construction, to adopt the armouring element, it must be incorporated into another support metal plate or layer.This metallic plate or layer be aluminium normally, and play the effect of heating panel, so that provide bigger surface area for the armouring element heat energy that is produced that dissipates.The assembly of aluminium sheet or layer is mounted to the metallic plate at the bottom of the formation heating container then.Although increased the area of dissipation of armouring element, but this aluminium sheet has increased the thermal mass of system significantly, and the increase of thermal mass causes adverse effect to operating efficiency again, because when initial, before heat transferred liquid, need more energy to make system warm-up.
The combination of armouring element and aluminium lamination or plate also causes job failure easily, that is, the armouring element is not mounted to aluminium sheet fully.At the place, any point of insufficient installation, can not diffuse to the aluminium sheet of heating panel effect fully by the heat of armouring element generation.As a result, at this some place, the temperature of armouring element may rise to very high level.Expanding with these " focuses " corresponding localized heat to cause element fault, perhaps causes progressively separating of element and aluminium sheet, and this can aggravate problems of excessive heat and acceleration components fault again.
Know that still exist and relevant structure and the work problem of existing silk screen printing thick-film resistor heating element, these problems are summarized as follows.
The thickness of the conductivity/resistivity printing ink that (a) applies in the silk-screen printing technique or inhomogeneity variation will cause the inhomogeneous of the final resistance element track that forms.The inhomogeneous meeting of this part causes producing " focus " in the element track, thereby causes job failure.
(b) in the final protection glaze layer that forms, there are any defective or hole, for example, can make the selective oxidation of resistive track, form hot localised points, thereby cause the track fault owing to leave the defective that the solvent vestige forms.
(c) element of silk screen printing is an orbit-shaped, normally helical orbit.Track is discrete, and is divided into parallel path more usually, and configuration is in order as far as possible farthest to cover area of base like this.Although adopt this configuration, in the practical application, the seldom part of having only area of base is by the actual covering of element, and therefore, for realizing good heat transmission by substrate, the working temperature of element need be far above the boiling point of institute's heated liquid.
(d) bringing another factor of adverse effect for the heat transmission from the element to liquid is the combination of metallic substrates and insulation glaze layer.The metallic substrates that has been used generally is stainless, with (such as) copper or aluminium compares, stainless steel has low thermal transmission coefficient.
The objective of the invention is to overcome or reduce the problems referred to above relevant with manufacturing technology significantly with known structure.
According to a first aspect of the present invention, a kind of resistance (property) heating element that is used for liquid is provided, it comprises: a substrate, this substrate is formed by electrical insulating material or is formed by the electric conducting material that has electric insulation coating layer, and substrate all provides a non-conductive surface at least one side in both cases thus; First and second contact zones of lateral isolation, they are arranged on the described non-conductive surface; And the resistive oxide skin(coating) of a thermal spraying, this oxide skin(coating) is coated on the subregion at least on described non-conductive surface, and be arranged at described contact zone subregion at least top or below so that electric current can be by described first and second contact zones resistive oxide skin(coating) of flowing through.
Term used herein " thermal spraying " and " hot-spraying technique " are meant any such technology,, adopt the particle of the composition of thermal source deposit metal, pottery or a metal fusing or semi-molten and ceramic material that is.
In a preferred embodiment, substrate is discoid, and the resistive oxide skin(coating) is circle or annular basically, but comprises a horn shape truncation part, and this truncation part is used to hold a temperature limit device.
Useful is, in one embodiment of back, first and second contact zones are separately positioned on the center and periphery of discoid substrate, and comprise corresponding tongue-shaped member, tongue-shaped member stretches in the described truncation part in the resistive oxide skin(coating), so that be formed for admitting the terminal area of described temperature limit device.
In one embodiment, the contact zone, center is circular, and peripheral contact zone is annular, and the resistive oxide skin(coating) so is coated on the described non-conductive surface, and is promptly overlapping with described contact zone at least in part.
In another embodiment, the resistive oxide skin(coating) is annular, and directly be coated on the described non-conductive surface, the contact zone, center is circular, and it is overlapping with the inner rim of the resistive oxide skin(coating) of annular, and peripheral contact zone is annular, and overlapping with the neighboring of the resistive oxide skin(coating) of annular.
In another embodiment, the resistive oxide skin(coating) is circular, and directly be coated on the described non-conductive surface, the contact zone, center is circular, and be arranged on the resistive oxide skin(coating), and peripheral contact zone is annular, and overlapping with the neighboring of resistive oxide skin(coating) at least in part.
The invention still further relates to a kind of manufacturing and be used for the method for resistance (property) heating element of liquid, may further comprise the steps:
(a) form a substrate by electrical insulating material or by the electric conducting material that has non-conductive coating layer, thus in each case, substrate all provides a non-conductive surface at least one side; And adopt following arbitrary mode:
(b) deposit first and second contact zones on described non-conductive surface; With
(c) by resistive oxide skin(coating) of previously defined a kind of hot-spraying technique coating, this oxide skin(coating) is coated on the expose portion on described non-conductive surface, so that partly overlapping, and between described contact zone, define a conductive path by the resistive oxide skin(coating) with described first and second contact zones; Perhaps
(d) by previously defined a kind of hot-spraying technique, on described non-conductive surface resistive oxide skin(coating) of coating and
(e) deposit first and second contact zones on the resistive oxide skin(coating) are to define a conductive path by the resistive oxide skin(coating) between described contact zone.
Under any situation, the resistive layer of thermal spraying preferably forms according to the technology of describing among EP-A-302586 and the US-A-5039840.
Useful is, under the situation of metal or metallic substrate, described non-conductive coating layer applies such thickness in substrate, and promptly it can bear the voltage of the 4000V at least that applies between substrate and the non-conductive coating layer surface and not puncture.
The element contact zone preferably is deposited on the non-conductive surface with configuration like this, that is, be suitable for reaching the maximum covering of resistive oxide skin(coating) to substrate, and can admit required temperature limit device.
Non-conductive coating layer preferably is the form of enamel or multiple metal oxide or nitride, and these materials are known to have high dielectric property, for example aluminium oxide, titanium dioxide and magnesium oxide.
Non-conductive coating layer can be in one or more step, with the form coating of enamel or a kind of insulating metal oxide or multiple oxide-metal combinations.It can adopt the plasma spray technology deposit or adopt according to (for example) the chemical technology deposit based on the principle of " sol-gel " technology.
Can be by sneaking into the thermal conductivity of other ceramic material raising non-conductive coating layer, described other ceramic material has suitable or better dielectric property, but has better thermal conductivity.These ceramic materials are the nitride of (for example) boron or aluminium.
The contact zone preferably is coated on non-conductive surface or the resistive oxide surface by physics or chemical deposition technology, and these technology comprise vacuum evaporation, magnetron sputtering, electrolysis or electroless deposition or any type of thermal spraying.
The contact zone preferably includes the combination of a kind of metal or multiple metal or other nonmetallic materials, and these materials are known to have high conductive characteristic, for example silver, copper, aluminium, nickel and gold.
The thickness in Metal Contact district is preferably such, and promptly they can carry the required maximum operating currenbt of this element, and this electric current is 15A usually to the maximum.
The configuration of contact zone is preferably such, that is, they will provide the maximum of resistive oxide skin(coating) on dielectric layer to cover, and if necessary, can also hold a working temperature restraint device.
The working temperature restraint device can be the conventional bimetal release type, the fusible link type or other heat effect form.
Useful is, the resistive oxide is such, that is, its surface is enough electric insulations, does not need to increase other protective layer.Can be alternatively or another non-conductive protective layer of coating on the exposed surface of resistive oxide and contact zone additionally.
Adopt method of the present invention, can obtain the resistive thermal spraying oxide skin(coating) of structure like this, promptly, the current density at any point place only is the sub-fraction of the total current of being carried on the oxide surface, if the contact zone is formed on the oxide surface, only be that a little leakage current flows out when work, so this element is than conventional discrete linear or strip element safety.
Because the advantage of component size and vpg connection, method and structure provided by the invention makes the resulting heating element assembly manipulation of being more convenient for, and makes and the liquid heat utensil might be designed to utilize best the useful space and reduce and produce material to minimum level.
Only the invention will be further described with way of example with reference to the accompanying drawings, in the accompanying drawing:
Fig. 1 and 2 demonstrates reverse cutaway view and the floor map extremely summarized according to the structure of first embodiment of resistive liquid heating element of the present invention respectively;
Fig. 3 is the floor map of the useful form of embodiment shown in Figure 1;
Fig. 4 is the cutaway view embodiment illustrated in fig. 3 along the intercepting of the line 3-3 among Fig. 3;
Fig. 5 and 6 is respectively floor map and a cutaway view according to a second embodiment of the present invention;
Fig. 7 and 8 is cutaway views of the 3rd embodiment and other embodiment.
At first with reference to Fig. 1 and 2, wherein for ease of describing, the thickness of each layer amplifies, and do not draw in proportion, this first embodiment comprises a substrate 10, this substrate is made by metal or other material, and manufactured materials has good thermal conduction characteristic and through the end required shape of processing/machine-shaping for a heating vessel of formation, perhaps can be mounted to easily on the pedestal of this container.In Fig. 1 and 2, shown substrate is circular, but principle say that it can be the shape of any needs.
Copper is normally preferably made the material of substrate 10 because its conductive coefficient be 377W (watt)/M (rice)/° K (absolute temperature), far surpass stainless conductive coefficient, the latter only is 18W/M/ ° of K.Round smooth disc shape is made in substrate 10 usually, and its diameter is suitable for being mounted on the relevant heating vessel or in the container of packing into.The substrate disc can be fully smooth, perhaps with other shaping structures, for example, has the flange of the assembling of the other parts that are used for auxiliary and container.
The side (upside of the reverse schematic diagram of Fig. 1 in substrate 10, but in actual manufacture process, be downside) dielectric of coating (non-conductive/insulation) layer 12, this dielectric layer is enough thick, so that it is not can bear the substrate 10 assigned voltage V between the outer surface of dielectric layer 12 therewith, and breakdown.Under a kind of typical situation, predetermined voltage V is approximately 4000V (volt).
Dielectric layer 12 can be made of suitable enamel (vitreous enamel), and its typical thickness approximately is 100 microns, so that reach above-mentioned voltage breakdown ability.Dielectric layer 12 can apply in arbitrary step or in the series of steps, and perhaps it can comprise metal oxide such as aluminium oxide, titanium dioxide or the magnesian series or the combination of heat spray, and its gross thickness remains usually about 100 microns.
In some cases, can strengthen the thermal conductivity of dielectric layer 12 by sneaking into other ceramic material, described other ceramic material have be equal to or better dielectric property, but have better thermal conductivity.The example of described other ceramic material comprises the nitride of boron and aluminium.
Applicator element contact zone 14 on dielectric layer 12.In the example of Fig. 1 and 2, the contact zone comprises the round contact zone 14a that is positioned at the center and is positioned at the annular contact zone 14b of periphery.The setting of these contact zones 14a, 14b is for the resistive heating element that electric current can will be applied by the back, and this heating element be will be further described below.
Contact zone 14a, 14b can adopt any suitable chemistry or physical deposition technology to be applied on the dielectric layer 12, for example vacuum deposition, magnetron sputtering, electroless deposition, silk screen printing or any type of hot spray technique.The contact zone can be by constituting such as in silver, gold, copper, these metals of al and ni one or more, and these metals are known to have the favorable conductive characteristic.The thickness in Metal Contact district only needs to satisfy carrying below with the requirement of the operating current of the liquid heating element of description, and this operating current reaches the typical maximum of 15A (ampere) usually, but in fact can be higher.
The size of contact zone 14a, 14b and structure are to set like this,, a working temperature restraint device (not shown) are installed if desired that is, and these contact zones will further describe as the practical embodiments in conjunction with Fig. 3 and 4, Fig. 5 and 6.
Now, coating forms a resistance element 16 on the surface of the exposure of dielectric layer 12, and this element covers zone between two contact zone 14a, the 14b and overlapping with these contact zones at least in part.
Such as the NiCr powder constituent, it adopts hot spray method and preferably applies by description among European patent application EP-A-302586 and the U.S. Pat-A-5039840 and claimed flame-spraying technology the resistive material of formation resistance element 16 by one or more pulverous metal oxides.
The parameter setting of flame-spraying technology is: the resistivity of formed metal oxide illuvium is about 14 Ω mms usually, under this condition, to have by the resistive oxide deposition layer of the structure shown in Fig. 1 and 2 spraying and can be operated in necessary thickness under the situation like this, and promptly be operated in the exemplary currents level of density and be approximately 0.8-1.0A/mm 2Situation under.
Adopt above-cited in the technology described in this patent as a reference, resistance element 16 can form in a plurality of passages (passes), to realize that (for example) has the resistance element of multiple deposition thickness, therefore, at the voltage that applies is under the situation of 230/240V, the resistance that finally obtains make element power output 1.5-3.0KW (kilowatt) in the scope.Other embodiment can have (for example) such illuvium resistivity and thickness,, can make the element of same general structure that is, but is under the situation of 110/120V at the voltage that applies, and the power output that can produce is in the 0.75-1.5KW scope.
Referring now to Fig. 3 and 4, these two the schematically illustrated practical embodiments of figure, this embodiment is similar to the embodiment of Fig. 1 and 2.For the corresponding component that shows among Fig. 1 and 2, adopted same reference numbers among Fig. 3 and 4.Therefore, this embodiment has also adopted the metal disc substrate 10 of a circle, dielectric layer 12, the interior contact zone 14a of a circle, outer contacting district 14b and ringwise basically resistive oxide skin(coating) 16 of an annular.But, as shown in Figure 3, in this embodiment, in order to hold (routine) temperature limit device (not shown), this different resistive oxide skin(coating) of annular electro comprises a horn shape truncation part between lateral edges 18a, 18b, exposes at this truncation part place dielectric layer 12. Contact zone 14a, 14b have corresponding integral type tongue-shaped member 20a, 20b, they radially outwards and inwardly stretch out respectively on the exposed region of dielectric layer 12, the installation site is provided thus, and the respective terminal of temperature limit device can be mounted to these installation sites.For example, by soft soldering connect, hard brazing filler metal or similar approach install.Temperature limit device plays an on-off action, and it is generally used for from power supply to resistive heating element 16 supplying electric currents, if but the ambient temperature around this restraint device surpasses certain level, and it just automatically cuts off described electric current supply.It can be (for example) conventional bimetal type, the fusible link type or other heat effect form.
The size of contact zone 14a, 14b and structure are so to select, that is, they can hold the working temperature restraint device, and can also allow resistive layer 16 dielectric layer most possibly.
In actual applications, this device certainly and the position-reversed shown in Fig. 4 so that substrate can form or be mounted on the pedestal of a heating vessel.Therefore, temperature limit device be installed in usually heating element in one of the container bottom room below.
Except following difference, Fig. 5 and 6 embodiment are identical with the embodiment of Fig. 3 and 4, that is: (a) to constitute the resistive oxide skin(coating) of the heating part of this element be continuous below the contact zone 14a in whole, therefore compare with the annular of resistive layer among Fig. 3 and 4 in fact become circular; (b) contact zone 14a can have than diameter littler in Fig. 3 and 4.Have found that, in this structure,, thereby provide corresponding heat effect, cover although it is touched element 14a fully to the core of small part current flowing resistance oxide skin(coating).
Obviously, in the embodiment shown in Fig. 1-6, contact zone 14a, 14b are at first coated, then at least in part by the 16 overlapping coverings of resistive oxide skin(coating), and in other embodiments, this process can be reversed, and promptly can at first apply resistive oxide skin(coating) 16, thereafter apply contact zone 14a, 14b, the latter is overlapping with the former at least in part.Therefore, in the embodiment shown in fig. 7, at first the resistive oxide skin(coating) 16 of an annular of coating on dielectric layer 12 applies interior and outer contacting district 14a, 14b then.In Fig. 8, at first apply the resistive oxide areas 16 of a circle equally, apply the interior contact zone 14a of a circle and the outer contacting district 14b of annular then.When see apparent time from plane graph, these embodiment of back also need form a horn shape truncation part as shown in Fig. 3 and 5 in the resistive oxide skin(coating), so that hold temperature limit device.
Such thick-film resistor liquid heating element has the advantage of many reality, and these advantages can be summarized as follows.
(1) as what seen from Fig. 1,3 and 5, electric current radially flows or presses rightabout from the inside contact zone 14a of outer contacting ring 14b and flows.Therefore, different with the situation of the existing element that comprises the printed circuit strip conductor, electric current is not to be confined to flow along arbitrary specific track.A consequent benefit is that the local damage of element can not bring injurious effects to element work.Electric current can increase its current density simply around local damage place.From this respect, element can be regarded as " adaptivity ", that is, this structure allows electric current to adapt to various variations in the resistive layer.Trouble-proof ability is extremely important to this " self adaptation " characteristic with strengthening it to bear local damage for the life-span of improving element.Conventional discrete rail type element does not have this adaptive ability.
(2) consider from component structure shown in Fig. 5 and size, should be pointed out that resistive illuvium 16 has approximately covered 86% of total area of base.This is than the printed circuit strip conductor type heating element of routine or the much higher coverage of coverage that reaches with the armouring type element of metallic plate combination.Therefore, the heat energy that is produced has much bigger transmission area, and thermal energy transfer is to wanting heated liquid on this area, and the result compares with the element of above-mentioned two kinds of general types, and element will be operated under the lower temperature.The working temperature of this reduction allows that this novel element is easier unites use with the low melting point polymeric material that is used to make liquid heating element at present.
Element provided by the invention can be lighter, therefore can have lower thermal mass (therma lmass) than dull and stereotyped armouring type element or thick-film printed circuit type element.For example, the weight of the dull and stereotyped armouring type of the 2KW of routine element is approximately 225/230g (gram), and the printed circuit type element weight of an identical fan-out capability is approximately 110g, and the typical weight of the thick film spray element of the present invention of a 2.5KW is approximately 95g.The difference of this weight aspect can so influence operating efficiency, that is, for lighter element, it is less when initial element to be promoted to the energy that the working temperature of requirement needs.
(4) thermal spraying element of the present invention can be by full-automatic technology manufacturing, only needs two/three simple steps (needn't according to this order): coating non-conductive layer 12 (if adopting metallic substrates) on metallic substrates 10; Metal Contact district 14a, the 14b of deposit high conductivity; And thermal spraying deposit resistive region 16.Each step of this manufacturing process all can be controlled in the little tolerance.
(5) another advantage according to element of the present invention is, they have low electromagnetic signature (signature) than the rail type element of routine.Its reason may be the radial current path of weak point and big cross-sectional area, and this electronics that allows to set up when cutting off the electricity supply gathers more easily dissipation.

Claims (26)

1. resistance (property) heating element that is used for liquid, comprise: a substrate, this substrate is formed by electrical insulating material or is formed by the electric conducting material that has electric insulation coating layer, and substrate all provides a non-conductive surface at least one side in both cases thus; First and second contact zones of lateral isolation, they are arranged on the described non-conductive surface; And the resistive oxide skin(coating) of a thermal spraying, this oxide skin(coating) is coated on the subregion at least on described non-conductive surface, and be arranged at described contact zone subregion at least top or below so that electric current can be by described first and second contact zones resistive oxide skin(coating) of flowing through.
2. according to the heating element of claim 1, wherein, substrate is discoid, and the resistive oxide skin(coating) is circle or annular basically, but comprises a horn shape truncation part, and this truncation part is used to hold a temperature limit device.
3. according to the heating element of claim 2, wherein, described first and second contact zones are separately positioned on the center and periphery of discoid substrate, and comprise corresponding tongue-shaped member, tongue-shaped member stretches in the described truncation part in the resistive oxide skin(coating), so that be formed for admitting the terminal area of described temperature limit device.
4. according to the heating element of claim 2 or 3, wherein, the contact zone, center is circular, and peripheral contact zone is annular, and the resistive oxide skin(coating) so is coated on the described non-conductive surface, and is promptly overlapping with described contact zone at least in part.
5. according to the heating element of claim 1, wherein, the resistive oxide skin(coating) is annular, and directly be coated on the described non-conductive surface, the contact zone, center is circular, and it is overlapping with the inner rim of the resistive oxide skin(coating) of annular, and peripheral contact zone is annular, and overlapping with the neighboring of the resistive oxide skin(coating) of annular.
6. according to the heating element of claim 1, wherein, the resistive oxide skin(coating) is circular, and directly be coated on the described non-conductive surface, the contact zone, center is circular, and it is be arranged on the resistive oxide skin(coating), and peripheral contact zone is annular, and overlapping with the neighboring of resistive oxide skin(coating) at least in part.
7. according to the heating element of each claim among the claim 1-6, be provided with a temperature limit device.
8. a manufacturing is used for the method for resistance (property) heating element of liquid, may further comprise the steps:
(a) form a substrate by electrical insulating material or by the electric conducting material that has non-conductive coating layer, thus in each case, substrate all provides a non-conductive surface at least one side; And adopt following arbitrary mode:
(b) deposit first and second contact zones on described non-conductive surface; With
(c) by resistive oxide skin(coating) of previously defined a kind of hot-spraying technique coating, this oxide skin(coating) is coated on the expose portion on described non-conductive surface, so that partly overlapping, and between described contact zone, define a conductive path by the resistive oxide skin(coating) with described first and second contact zones; Perhaps
(d) by previously defined a kind of hot-spraying technique, on described non-conductive surface resistive oxide skin(coating) of coating and
(e) deposit first and second contact zones on the resistive oxide skin(coating) are to define a conductive path by the resistive oxide skin(coating) between described contact zone.
9. method according to Claim 8, wherein, under the situation of metal or metallic substrate, described non-conductive coating layer applies such thickness in substrate, and promptly it can bear the voltage of the 4000V at least that applies between substrate and the non-conductive coating layer surface and not puncture.
10. according to Claim 8 or 9 method, wherein, the element contact zone is deposited on the non-conductive surface with configuration like this, that is, reach the resistive oxide skin(coating) maximum of substrate is covered, and can admit required temperature limit device.
11. according to Claim 8,9 or 10 method, wherein, non-conductive coating layer is the form of enamel or multiple metal oxide or nitride, and these materials are known to have high dielectric property, for example aluminium oxide, titanium dioxide and magnesium oxide.
12. according to Claim 8,9 or 10 method, wherein, non-conductive coating layer is in one or more step, with the form coating of enamel or a kind of insulating metal oxide or multiple oxide-metal combinations.
13. according to the method for claim 12, wherein, non-conductive coating layer is to adopt the plasma spray technology deposit.
14. according to the method for claim 12, wherein, non-conductive coating layer is what to adopt based on the chemical technology deposit of " sol-gel " technology.
15. method according to Claim 8, wherein, by sneaking into the thermal conductivity of other ceramic material raising non-conductive coating layer, described other ceramic material has suitable or better dielectric property, but has better thermal conductivity.
16. according to the method for claim 15, wherein, described other ceramic material is the nitride of boron or aluminium.
17. the method for each claim according to Claim 8-16, wherein, the contact zone is coated on non-conductive surface or the resistive oxide surface by physics or chemical deposition technology, and these technology comprise vacuum evaporation, magnetron sputtering, electrolysis or electroless deposition or thermal spraying.
18. the method for each claim according to Claim 8-17, wherein, the contact zone comprises the combination of a kind of metal or multiple metal or other nonmetallic materials, and these materials are known to have high conductive characteristic.
19. according to the method for claim 18, wherein, described metal comprises any in silver, copper, aluminium, nickel and the gold.
20. according to the method for claim 18 or 19, wherein, the thickness in Metal Contact district is such, promptly they can carry the required maximum operating currenbt of this element.
21. the method for each claim according to Claim 8-20, wherein, the configuration of contact zone is such, that is, they will provide the maximum of resistive oxide skin(coating) on dielectric layer to cover, and can also hold a working temperature restraint device.
22. according to the method for claim 21, wherein, the working temperature restraint device is the bimetal release type, the fusible link type or other heat effect form of routine.
23. the method for each claim according to Claim 8-22, wherein, the resistive oxide is such, that is, its surface is enough electric insulations, and does not need to increase other protective layer.
24. the method for each claim according to Claim 8-22, wherein, can be alternatively or another non-conductive protective layer of coating on the exposed surface of resistive oxide and contact zone additionally.
25. a resistive heating element, in fact as describe with reference to the accompanying drawings previously and show by accompanying drawing.
26. a method of making the resistive heating element is in fact as describing with reference to the accompanying drawings previously.
CN 96194586 1995-06-08 1996-06-07 Electrical heating elements Pending CN1187284A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN 96194586 CN1187284A (en) 1995-06-08 1996-06-07 Electrical heating elements

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9511618.2 1995-06-08
CN 96194586 CN1187284A (en) 1995-06-08 1996-06-07 Electrical heating elements

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100493267C (en) * 2000-11-29 2009-05-27 萨莫希雷梅克斯公司 Resistive heaters and uses thereof
CN104882850A (en) * 2014-02-28 2015-09-02 斯玛特电子公司 Complex protection device of blocking the abnormal state of current and voltage

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100493267C (en) * 2000-11-29 2009-05-27 萨莫希雷梅克斯公司 Resistive heaters and uses thereof
CN104882850A (en) * 2014-02-28 2015-09-02 斯玛特电子公司 Complex protection device of blocking the abnormal state of current and voltage

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