CN1135060C - Electric heaters - Google Patents

Abstract

The desired power rating of a thick film heater is obtained by making electrical connections to the heater track at positions which define the appropriate resistance therebetween.

Description

Electric heater

The present invention relates to electric heater, the heater in particular for the flat-panel component type of household electrical appliances such as hot-water stove, water heater and flatiron has other some application in addition.

A panel heater comprises one deck dielectric substrate, and a resistance heating trace is housed on the substrate.Usually, glass, pottery or a glass ceramics insulating barrier are installed on the metab such as metallic plate, are equipped with track on the insulating barrier.Foregoing can realize that for example, the thin resistance material of bonding one deck on substrate, or employing printed circuit technique more commonly used are layered on one deck resistive seal China ink on the substrate by several different methods, and metal spraying also is one of common method.Use any of these technology, its result is the heater of a plane form, and this heater can be made the base of heating container, or is made in above the base, or bonding with base, and is all very convenient.

Resistance heating trace also can be laid on nonplanar substrate, for example tubulose or other three-dimensional body.

EP-A-0574310 has announced the example of a hot-water stove, and this container is base based on plastics with printed circuit type panel heater.Electric terminal is made in the end of each helical orbit, is connected to power supply by the lead that is connected on the track.

Yet the printed circuit heater of production wants to have identical resistance value and obtains identical power output thus, is very difficult.Time and variation of temperature in the nominal resistance rate difference of the difference of printing track thickness, seal China ink and the technical process will cause the difference of last turn resistance, so also difference of the power of heater.In fact, manufacturer can power maintain nominal value ± 15% with interior just good.But, international electrical standard regulation power be maintained at nominal value+5% and-10% between.Clearly, iff being suppress out-of-size that part of, do as some manufacturer, percent defective will be very high so, may reach 25%, and this is to waste very much and costliness.

Various trials have been made for overcoming these problems.By using precious materials and indoor cleaning equipment can improve manufacturing tolerance.But do too expensive like this.In addition, can use laser " shearing " track to improve its impedance.But, for the track that requires to make the 2kW thermal effect, make in this way both difficulties and expensive.

The present invention attempts to address these problems.According to a first aspect of the invention, a heater assembly is provided, it comprises an electric heater, described electric heater comprises a resistance heating trace that is layered on one deck dielectric substrate, this electric heater has an electric terminal position at least, this location-appropriate ground separates with heater tracks with one section material, the resistance value of this section material is significantly less than the heating rail material, described heater assembly comprises that also described spring contact is made or is installed on the spring leaf by a spring leaf with a spring contact of described connecting point position contact.

According to a second aspect of the invention, a kind of heating vessel is provided, it comprises a heater assembly, described heater assembly comprises an electric heater, described electric heater comprises a resistance heating trace that is layered on one deck dielectric substrate, this electric heater has an electric terminal position at least, this location-appropriate ground separates with heater tracks with one section material, the resistance value of this section material is significantly less than the heating rail material, described heater assembly comprises that also described spring contact is made or is installed on the spring leaf by a spring leaf with the contacted spring contact of described connecting point position.

And, from first kind of angle, invention has provided a kind of method of making the electric heater device, this device comprises a heater, this heater comprises a resistance heating trace that is laid on one deck dielectric substrate again, and corresponding to the heater power that requires, this heater has predetermined resistance value, and the method that invention provides comprises:

A) be covered with a resistance heating trace on substrate, the resistance value of track is greater than its predetermined value;

B) determine the position in orbit, make resistance therebetween reach predetermined value so that draw contact herein; And

C) make electric terminal in this position of track.

Like this, according to the present invention, the resistance of resistance heating trace is had a mind to make and is higher than required value (high by 5% under the poorest tolerance conditions), and draws electric terminal in selected position, makes the track resistance between electric terminal reach required value.

Make in this way, waste product is eliminated basically, the track resistance that does not need expensive manufacturing equipment and material just can obtain requiring simultaneously.

For heater, its predetermined value does not need to provide the quota in " nominal ", but has a kind of selectivity, for example can be any point in the target call margin of tolerance.The heater energy that for example selected resistance again produced is preferably in-10% zone of the margin of tolerance, can reduce the power density of heater like this and prolong its life-span therefrom.

In the actual production process, track is done to such an extent that require length more longer than what it reached the predetermined nominal resistance value, and inwardly makes electric terminal from an end of track at least, with the track resistance value that obtains requiring.

Therefore, from second kind of wider angle, the invention provides a kind of electric heater device, this device comprises a heater, heater has a resistance heating trace that is layered on the insulating barrier, leaves an one terminal place in heater tracks and does an electric terminal that connects power supply source.

Can there be several different methods the position of determining electric terminal in orbit.First method can be measured the all-in resistance of track earlier, thus, and after knowing the resistivity of rail material, just may be calculated the amount that track should shorten when reaching requirement resistance.Also can from form or similar form, obtain a series of mensuration resistance value, and with this amount of coming the budget track to shorten.In addition, can directly measure the resistance value of point-to-point transmission selected on the track, till reaching requirement.

Every docking point, the position of one of them can be fixed, for example the end points of track.In addition, one of contact also can require the position just to be made on the track before determining at another.

The connecting point position that separates that has some on the track, for example one or more contact pads, electric terminal just can be made in these places.

In case the connecting point position that requires has been determined, just can make electric terminal in these positions.This situation may occur: heater itself is not done contact when producing, but when subsequently heating container being installed, the contact of heater need add.In this case, heater can have the location point that some play indicative function when installing, and will make electric terminal after these are local.For example, can make sign at the relevant position of track.

Therefore, from another wider angle, the present invention also provides a kind of method of producing electric heater, this electric heater comprises a resistance heating trace that is laid on the insulating barrier, and corresponding to the power that heater requires, heater has corresponding predetermined resistance, and this method comprises:

A) lay a resistance heating trace on substrate, the resistance value of this track is greater than predetermined value;

B) determine the position in orbit, so that, make resistance therebetween reach predetermined value at these local electric terminals of making; And

C) make sign to heater so which place of indication track should need to make electric terminal afterwards.

This heating track can be the sort of of requirement band protectiveness glaze layer.If like this, before or after establishing, the electric terminal position that requires adds glazing layer, all allow.First method can be established connecting point position earlier, adds the glaze layer, will make one or more windows so that below the connection track in the appropriate location of glaze layer.Second method can add the glaze layer that has one or more windows earlier, and the purpose of window is to connect the track below, at the connecting point position of selecting under the suitable enabled condition on the track, makes resistance therebetween reach required value then.

But track preferably adopts a kind of material of not needing protection property glaze layer.Reduced manufacturing expense by the step of removing the glaze layer like this, and it is also more simple to connect track.

The top of track can be done several contacts to become electric terminal.If like this, can make several pads that touch at the location-appropriate that track requires, for example can be made in the window of protectiveness glaze layer.But track has directly just preferably been done electric terminal.So just avoid installing in orbit independent contact, reduced corresponding expense simultaneously.

Therefore, track more preferably adopts and can print the seal China ink that can spray and make through spraying or printing, and does not need to contain the glaze layer of pure nickel or Langaloy.

Therefore, in preferred embodiments, track exposes basically, is not with the glaze layer, and like this, track need not installed independent contact just can make contact.

The track contact can be welded by scolding tin or brass, but preferably adopts a contact to abut against on the track connecting point position and form electric terminal.Therefore this contact preferably adopts spring contact.Such contact can be installed on the contact supporting easily, and this touches the control section that the sand support has formed heater, will do further main the discussion hereinafter to this.This contact is preferably blade-like, makes contact and interorbital have the excellent contact line.

Can select the shape of track for adapting to concrete purposes.But usually, very responsive by the heater that printing or spraying circuit are made to sharp bend, because the current density in knee strengthens, will cause potential heat spot to damage heater.Therefore generally should avoid sharp bend, helical track, for example circular spiral track are adopted in therefore common haughty choosing.Simple spiral has such advantage: the voltage between adjacent orbit descends slow, so just helical orbit closely can be arranged in and avoid interorbital the danger of electric arc to occur together.

In the practical application, as above-mentioned, in the place of making the heater tracks electric terminal by the contact of support, contact relative position to each other will be fixed, and doing like this is convenience on producing.Therefore, preferred track should satisfy: the diverse location with some is installed contact, and between the position is certain at interval.Because track space is parallel, so foregoing can be easy to realize that each electric terminal can be made on the track respectively.

Like this, in the above-described embodiment, track is inside and outside to have parallel segmental arc, preferably preferably adopts ring segment, has a part at least for around shape and preferably adopt its essential part for around shape.Regardless of interorbital structure, especially preferably adopt ring segment, this is because heater and contact can be walked always to place with the rotation of a requirement, to reach the resistance of requirement heater.Be appreciated that inner section is equivalent to the disk of track outer portion part on its axis or the form of round dot.

When heater was installed, when being contained in the bottom of hot-water stove, the rail joint of heater can be changeless with respect to the position of container.Therefore, the installation site of heater in container must be satisfied: when container installed, rail joint must be in the tram to reach the power that requires of heater.Be the convenient foregoing of realizing, must do not make the position indication of electric terminal on heater, but making indication on the heater with the corresponding base on the aligning container on schedule, heater serves as correct with respect to the position of contact when installing with assurance.

Therefore, from wider angle, the invention provides a kind of method of producing heating vessel, one of this container composition is a kind of electric heater, and this electric heater comprises a resistance heating trace that is laid on the dielectric substrate, corresponding to the power that requires of heater, heater has certain predetermined resistance, and the one group of electrical contact that is used for drawing contact, these contacts are arranged on the precalculated position relevant with container, and the method that invention provides comprises:

A) resistance heating trace on the substrate upper berth, this track resistance value is greater than predetermined value;

B) determine the position that heater should be installed with respect to container, like this, the container contact is installed is constantly just formed electric terminal, make interorbital reach predetermined resistance value with track;

C) on heater, make designated symbol with indicating positions, be used for aiming at the datum mark on the container, like this, on container, install in heater and the contact, just can make electric terminal in the position that requires of track;

D) heater is installed on container, heater has the designated symbol of alignment fiducials point; And

E) electrical contact of this position on the installation heater

The definite of calibrating position can be realized by several different methods.For example, the all-in resistance of track can be measured, the position that is used to refer to can from the table find, what show in the table is for the different mensuration resistance value of track, from rail end point to displacement certain angle or straight line that has between the indicating positions.Known the nominal resistance rate of rail material per unit length, these data just can calculated in advance draw, and perhaps better way is to draw from actual measurement.

As mentioned above, contact is preferably mounted in the control unit of container, and this control unit is installed on the base of container.For example, this control unit can be provided with one element played the function of superheat protecting function, and more for example, this control unit can comprise a reset switch, and in the time of the control unit installation in position, reset switch is arranged on the thermal contact of heater.But this control also can be a kind of automatically controlled mode, and this has just become another preferred feature of the present invention.

In the electrical control of the heating vessel that everybody is familiar with, electric component needs a driving voltage that is lower than principal voltage, and it is generally 50V when supply power voltage is 240V.Up to the present, this driving voltage all is to obtain through suitable approach from main power source.But the present invention has preferred characteristics, and promptly driving voltage can be obtained by the contact of heater tracks itself.Therefore, preferred heater tracks has a connecting point position at least between each power supply connecting point position, " to pick up " one section intermediate voltage from track.

For plate heater provides the notion of a driving voltage itself novel, therefore from another broad angle, electric heater provided by the present invention says to be exactly that it includes a resistance heating trace that is layered on the dielectric substrate altogether, and a cover electrical control gear.On selected position, done electric terminal between its middle orbit and the control unit, to provide control required driving voltage.

From another perspective, the present invention has carried a kind of electric heater, and it comprises a resistance heating trace that is layered on the dielectric substrate, and a connecting point position is arranged between the end of track, and in order to obtain one section voltage from track, this voltage is lower than the supply power voltage of track.

The position of this contact can be determined by experience.For example obtain 50V voltage from the power supply of 240V, contact approximately should account for 1/5 of heater tracks length.

In above-mentioned heater track duct device, have the company of some parallel orbital segments to power supply, if the position of intermediate contact is fixed on the track, so when the contact that connects power supply changes, the voltage that the different heating device is obtained from this point still can be different, because the track relative length of intermediate point both sides is all changing.Therefore, track can have a contact section to be parallel to power supply source contact section in addition.For example, a helical orbit can add an arc-shaped rail section between the original circular arc terminal position of track.Spatial relationship between power supply contact and intermediate voltage contact is regularly pre-, uses this parallel orbit device and especially has superiority, for example can be contained on the ordinary stent such as the control support.In this device, because for meeting the requirements of the track resistance value, its relative position changes between track and power supply contact, so the position of intermediate contact also changes, to a certain extent, this has offset the variation of track with the track length ratio of power supply contact both sides.

Obviously, the present invention also prolongs in broad terms and arrives and invent the heater that is suitable for.Therefore, from the angle of another one broadness, the invention provides a kind of heater, it comprises a resistance heating trace that is layered on the dielectric substrate, have electrical contact on the track, this contact separates with track one end at least, and this end points can be made a power supply contact.

The part of track self is preferably adopted in this contact, though, equally also can adorn one or connect an independent electrical contact in orbit.

Preferably track has first exposed length in order to first power supply contact of connection track, and second exposed length that is parallel to first section, in order to connect second power supply contact on the track.

First section and second section coaxial circular arc of preferably preferred employing.For example, inner section can be located at the place near the heater tracks center.But in another embodiment, track is not an independent spiral form, but can be by self be folded to form, and inner tracks just is arranged on the place of contiguous external orbital section like this, and becomes in the other direction with the external orbital section work.Such device has following advantage: because two contact sections are all occupied relatively large ratio, so the necessary words of device can realize interior resistance change on a large scale.But the possible shortcoming of this device is: exist bigger voltage because of potential between the adjacent bend of track, so must keep farther distance between bend.

Necessary, most parallel track segments can be contained in an end of track, to realize resistance change in larger scope, selectively one in the orbital segment or else make an electric terminal.

In addition, track can comprise the 3rd exposed length, and this section is parallel and between first and second section, it can make the another one electric terminal to obtain a voltage that is lower than supply power voltage from track.Therefore in the embodiment of optimum, track can comprise three coaxial arc sections.

The heater substrate preferably adopts a flat type, preferably preferably adopts the metallic plate of a tape insulation layer.

Resistance track and its different connecting point positions can be made by identical resistance material, and/or have identical resistivity.But, connecting point position or joining zone can be made by being different from other local material of track and/or resistivity and/or width, for example, realize by the multichannel typography, in this technology, the different resistance materials or the resistance material of different-thickness successfully are laid.Specifically, the material of connecting point position or joining zone can be a kind of material that is easy to make contact, for example a kind of material that is difficult for oxidation.

And though heater tracks of the present invention preferably is substantially disposed in same plane, it also can be arranged on a plurality of planes.For example, it can have first orbital segment that has covered glaze layer or similar thing, and second segmentation that is installed in the band connecting point position above the glaze layer, between two segmentations of track electric terminal is arranged.

Be appreciated that the notion that an intermediate contact position is set has purposes widely than only only limiting to electrical control on heater tracks.Therefore, the centre position can not only be used for picking up one section voltage from track.

For example, can come application controls that track is powered selectively by one or two heater tracks section.Therefore the different piece of track can have different resistance values or different thermal effects, for example, can be used for hollow jar or similar thing to it, and the effect that makes liquid boiling or slow fire is provided.

Therefore, on very broad meaning, the present invention also prolongs and to an electric heater, this electric heater comprises a resistance heating trace that is layered on the dielectric substrate, and this track has an electrical contact position, and this position is between track end.

The present invention also prolongs and to a hot-water stove, this hot-water stove has been introduced according to a heater of the present invention or heater assembly, and the main method that invention is also prolonged and is made this container, this method have been introduced the step of producing heater assembly in the method according to this invention.

Above mention, track can be made with other local different material of resistance heating trace by a kind of in the zone of nearby contact position.Can see from another aspect of the present invention, between an electric terminal position section and heating track, suitably form relatively good with the low electrical resistant material such as silver.The advantage of above-mentioned way is: this part of track can not produce a large amount of heat, and this will reduce the heat that passes to connecting point position, has just reduced the heat that passes on the contact of being made by this zone yet.Under overheated condition, this place contact repeat the malleableize that heating can cause spring leaf, cause contact pressure to reduce, caused the resistance heat production aggravation of contact position conversely, the benefit of above-mentioned way has embodied.

Therefore, from another perspective, the invention provides an electric heater, this electric heater comprises that is layered on a resistance heating trace on the dielectric substrate, this heater has an electric terminal position at least, and suitably separate with one section low electrical resistant material between this connecting point position and the heating track, preferably, the resistance value of this material is more much lower than the resistance value of heating rail material.

This low electrical resistant material preferably adopts the very high material of silver or silver content.This will be for the normal heating track provides good electric terminal, and the thermal effect that produces is very little.

Joint location is preferably made a contact pads, for example uses silver, and this makes a good electric terminal for heater and prepares.

This low electrical resistant material can cover heating track top layer or hot below the heating track partially or completely.But, it preferably with the heating track the end segment overlaid.This section low electrical resistant material will be determined in a box, by providing sufficient thermal insulation for contact at the bottom of the box.But the length of this low electrical resistant material is preferably minimum 8mm.

In preferred embodiments, use traditional track to apply technology and use this low electrical resistant material, for example serigraphy.Therefore, this material can use Yin Mo a kind of silver or that contain a large amount silver.

Also prolong this aspect of the present invention and to a heater assembly, it has a spring contact that contacts with connecting point position, preferably preferably adopts a spring leaf to make contact, or contact is contained on the spring leaf.As mentioned above, the problem that contingent contact pressure reduces, and the actual biography that takes place all can be eased by the present invention to the heat transmission of other parts in the utensil.

Embodiments more of the present invention here will only reach by way of example and narrate with reference to the accompanying drawings, wherein:

Accompanying drawing 1 is the perspective view of the heater according to the present invention;

Accompanying drawing 2 shows the heater tracks side of accompanying drawing 1;

The heater that accompanying drawing 3 shows Fig. 1 is positioned on the base of a heating vessel;

Accompanying drawing 4 shows a controlling organization that is used for heater, and it is positioned on the heater;

The controlling organization that accompanying drawing 5 shows accompanying drawing 4 is installed on the heater;

Accompanying drawing 6 is plane graphs that are applicable to another form of heater tracks of the present invention;

Accompanying drawing 7 is another embodiment of the invention; And

Accompanying drawing 8 has shown another embodiment of the present invention.

With reference to accompanying drawing 1 and accompanying drawing 2 a thickness film panel heater 2 has been described, heater 2 be used for being made in a hot-water stove the base the inside or above, perhaps make base.It comprises the corrosion resistant plate of diameter 81mm, a thick about 0.5mm; the ceramic layer 6 that an electric insulation is arranged on the surface of steel plate; the top of ceramic layer 6 printed a thick-film resistor heating track 8 in a kind of mode that everybody is familiar with; track 8 is pure nickel or Langaloy; for what expose, be not with protectiveness glaze layer on its length.

8 about 2.4mm are wide for track, and it comprises an annular end segment 10 in outside and an inner annular end segment 12, and end segment 10 has the constant mean radius R of an about 34.5mm ₁, it is the periphery of the flat board 4 of full extension basically, and end segment 12 has a constant mean radius R who is approximately 5.25mm ₂, it has launched about 300 ° around the axis of flat board, and end segment 12 is coaxial with external end section 10.Track 8 also has the coaxial annular section 14 of a centre, and ring segment 14 has a constant mean radius R who is approximately 16.75mm ₃

Ring segment 10,12,14 link to each other with the inside and external helicoid section respectively.Transition between each spiral section and ring segment is level and smooth curve, has avoided the heat spot that the electric current gathering occurs and cause thus at the overbending place like this.Spacing between the adjacent bend of helical orbit section is approximately 0.8mm～1.0mm.An erection column bolt is installed in dull and stereotyped 4 center.

Dull and stereotyped 4 will be installed in the top or the inside of the base 24 of heating vessel 26, perhaps make base 24, illustrate as accompanying drawing 3.And, the projection of the electric contact of installing by each elasticity 30,32,34 from the fuselage 36 of an electric control unit of heater, electric terminal has been made in three positions 9,11,13 of track 8, these three positions respectively occupy one on each ring segment 10,12,14 of track, (meaning as shown in accompanying drawing 3).As shown in accompanying drawing 4, control fuselage 36 be installed in column bolt 20 above.

Control fuselage 36 is installed on the container base, and it is predetermined with respect to the angular orientation of the datum mark 38 of accompanying drawing 3 signals.Contact 30 and 32 and is installed in the lead of control on the fuselage 36 and links to each other with power supply neutral line terminal, come to track 8 power supplies, and contact 34 connects the electric component to controlling organization, is used for from track 8 driving voltage of acquisition to drive these electric components.

Total resistance that track 8 has when making realizes the required resistance value of this heater requirement power from measuring between its end points to be greater than.Therefore, the power supply joint must be guided the appropriate location of inside and outside track section 12,10 into by the contact 32,30 of control fuselage 36, like this, makes its resistance reach predetermined value corresponding to the requiring power of heater with regard to the track length that defines therebetween.

Because the installation site of control fuselage 36 is fixing with respect to container base, so when assembling this container, heater 2 must be installed on the base of container with a special angular orientation, when guaranteeing on container base 24 installation and control fuselage 36, contact 30,32 should be connected in place with track 8.For convenience of foregoing, heater has been indicated a designated symbol 42, so that aim at the benchmark in the container 38.

A kind of method of setting up the designated symbol position is to measure the all-in resistance of track 8, comes calculating location then in view of the above, has passed through the resistivity of rail-engaging road length, rail material and with respect to the position of datum mark 42, electric terminal just can be made on the interior track of container.For example, in order to obtain the resistance value of track requirement, the amount that track should be shortened can be come out by given data computation, so the position of designated symbol is from scheduled volume of an end fitting displacement when heater is installed, this scheduled volume has been considered the relative position of connecting point position with respect to container.Form can be calculated and make to these data all in advance, when so in the end middle production and check, just can obtain suitable position as long as read form, perhaps calculates the appropriate location that is used for each element.

Another determines that the method for designated symbol position on the heater is the resistance of measuring between a pair of probe, and the relative position between probe is identical with 30,32 of contacts.Reach requirement around whole mobile two probes of the axis of track 8 until the resistance value of measuring.In case arrive this position, designated symbol 42 just can be made on the heater 2, and should locate identical with respect to the orientation of container datum mark 38 with contact 30,32 with respect to the orientation of the connecting point position of determining.For example, if contact 30 is configured to from the skew of 38 10 ° of datum marks, so, the sign 42 on the heater is configured to the skew of 10 ° of on the external orbital 10 corresponding connecting point positions.

So, the heater band the designated symbol of aiming at datum mark 38 42 and is installed on the container base 26, controlling organization 36 is installed on the container base subsequently, for obtaining the predetermined value of track resistance, should make electric terminal between contact 30,32 and track 8 interior correct positions.

Intermediate orbit section 16 has also been made electric terminal by contact 34.This contact makes the voltage of obtaining from track be lower than supply power voltage, with the electric component in the drive controlling mechanism.

Because middle and terminal rail section is concentric,, just can make gratifying contact on the intermediate orbit section 14 so needn't consider to control the relative angular position between fuselage 36 and the heater tracks 8 substantially.

The purpose of contact 34 is in the position of narration above in the middle of being provided with, and the voltage that order obtains is required value.

In the embodiment of signal, the voltage that takes out from intermediate contact will be approximately 1/5 of power supply voltage, and promptly the power supply voltage for 240V approximately is 50V.Therefore, the intermediate contact of making on the track approximately should account for 1/5 of track length.Because the variation of the relative orbit length between intermediate contact and the terminal contact is done slight variations by the precise voltage that contact 34 is obtained with the relative angular position between control fuselage 36 and the track 8.But this variation can be greatly to influencing control element conversely.

In the above-described embodiment, the resistance change that may reach approximates the resistance of outside circular orbit section 10 greatly.Actual middle orbit area (resistance also is like this) minimum and maximum value roughly may be limited between the contact of valley, approximately is respectively 2500mm ²And 2100m ², possible area change total amount reaches 400mm ², account for 19% of resistance minimum zone greatly.

Use the heater tracks structure of accompanying drawing 6 signals can reach bigger variation.In this embodiment, track 50 is double-helical structures, its ragged edge be one in this annular end segment 52, the inside closely is provided with the end segment 54 of the basic annular of another one.In embodiment in front, each end segment 52,54 has been made electric terminal respectively.Because the length of the track end section 54 of inner annular is big than in the embodiment of front basically, also because each end segment 52,54 each other with opposite direction work, this device just can have the advantage that realization is regulated in larger scope.Like this, have the possible resistance variations of this trade shape equal track section 52,54 length and.

If to track use as indicated above the sort of be gas control system, an other circular orbit section can be adorned in place.

In this embodiment, for example because track 52 and 54 can be under the potential sufficient line voltage each other, institute thinks and prevents that electrical breakdown from must make the spacing between the contiguous bend of track keep enough greatly.Therefore common spacing is 2mm.

Narrated another embodiment of the invention in the accompanying drawing 7.In this embodiment, a heating track 60 comprises an inner section 62 and an outer portion part 64, and inner section 62 has the lower resistance of about 14 Ω, and outer portion part has the higher resistance of about 190 Ω.Track laying exists, such as being to be printed on one deck dielectric substrate, be coated with on the substrate, such as being to be printed with an external contacts circle 66 and an inside contact circle 68, the outer portion part that contact circle 66 connects to track, the inner section that contact circle 68 connects to track, the contact pads 70 of some is arranged on the interlude 72 of track 60.These contact circles and pad are to be made on the track with a kind of material that can good conductive.They do not need to produce thermal effect.The glaze layer of a protectiveness is located on the heating track 60, has write down contact pads 70 but this glaze layer has window when installing, and does not inwardly prolong and inside contact circle 68 or outwards do not prolong and external contacts circle 66.Like this, no matter why, via the Internal and external cycle 66,68 and the contact pads 70 that expose, electrical contact has been made on the track.

This heater will be used for hollow jar or similar thing, in these local thermal effects that need be different, the liquid in the container need be boiled at first, and need slow fire to simmer.

Accompanying drawing 8 has shown the part of a heater assembly according to another embodiment of the invention.By a segment length is 4.0mm, and wide is the spring leaf contact 78 of the silver-plated beallon of 0.2mm, has had between controlling organization 74 of heater assembly and the electric heater 76 to be electrically connected.

In service at heater assembly, controlling organization is to heating track 80 power supplies of a palladium-silver of electric heater 76.82 places all terminate with a bullion " tail " each end of heating track 80 at the junction point.That silver tail 84 is to use silver or the Yin Mo that contains a large amount of silver, the film made from the pot impression method.During the manufacturing, before or after resistance heating trace 80 is added on the heated substrate, can be added in silver-colored tail 84 on the heated substrate.Under two kinds of situations, heating track 80 and silver-colored tail 84 all at the junction point 82 places overlapping, just can carry out good electrical conductivity between them like this.Covered one deck glass above the silver tail, glass ceramics, but a tail end points place at distance junction point 82 farthest, cover layer exposes the silver contact pad 86 of a diameter 8mm.Spring leaf 78 contacts with contact pads 86 with a contact pressure that is about 150gm (being not less than 100gm), thereby carries out electrical conductivity by silver-colored tail 84 and heating track 80.

It will be appreciated that, separate with silver-colored tail 84 between resistance heating trace 80 and the spring leaf contact 78 that this silver-colored tail 84 is 100mm from the length between edge to the junction point 82 of contact pads 86.There is not the direct heating of heater tracks 80 like this on the contact 78.The low resistance of silver tail prevented the resistance heating in contact pads zone, therefore reduced should the zone temperature, especially under overheated condition.

Use the device shown in the accompanying drawing 8, the dry type switch of a 2.2kW is in 7 second cycle, and the maximum temperature that spring leaf 78 arrives is 150 ℃.Resemble force to require in the test through this cycle of 50 hours, the contact pressure on the spring leaf 78 is owing to being heated the former of malleableize thereby descended about 15%.Therefore contact resistance between spring leaf 78 and the contact pads 86 rises, and the value that rises to is not more than 10m Ω, compares this rising with initial value 7m Ω and can accept.In this case, for a 2.2kW, the heater of 9A, the power loss at contact place will be less than 1W.

Above-mentioned embodiment can change within the scope of the invention.For example, rail material 80 can be below silver-colored tail or above extend to contact pads 86, but more effectively use contact pads 86 with its short circuit.

Though in above-mentioned embodiment, substrate is shown as one flat plate, its periphery can have groove in fact, purpose be it be installed in container base the inside or above.In this device, plastic containers sidewall or base can have the circuit that a part of supporting is used for bearing and installing heater downwards.Said apparatus has narration at our PCT application WO96/18331.

The present invention is not limited to plate heater, and being equally applicable to its substrate local is tubulose, the heater of polygonal or three-dimensional structure.

And, though specific embodiment narration generally is toroidal helical, also can use other trade shape, for example triangle or rectangle or other polygon spiral, they all have the alternate bend that a series of size reduces gradually.For example track is used a rectangular flat, and the track bend can be filled dull and stereotyped edge with rectangle mostly.

" spiral shell is executed " then the meaning of this word just can explain widely, rather than be confined to crooked spiral.

And, not only be confined to use crooked heating track from broad sense the present invention, but any trade shape, or even a straight rail.Importantly can require the position to make the track resistance of electric terminal to obtain to be scheduled to of track.So just can see, on very wide meaning, invention has provided a kind of method that obtains electric heater, this electric heater has the power output of requirement, comprise and assist resistance heating trace on dielectric substrate, be also included within the track certain position and make the electric terminal of power supply, make resistance therebetween be defined as suitable value.

At last, though the present invention of Gong Buing in preferred embodiments is used for a hot-water stove, it also can be used for for example other water heater, for example be used for dishwasher again or flooded heater, or such as flatiron other utensil.

Claims (5)

1. heater assembly, it comprises an electric heater, described electric heater comprises a resistance heating trace that is layered on one deck dielectric substrate, this electric heater has an electric terminal position at least, this position separates with heater tracks with one section material, the resistance value of this section material is significantly less than the heating rail material, and described heater assembly comprises that also described spring contact is made or is installed on the spring leaf by a spring leaf with a spring contact of described connecting point position contact.

2. according to the heater assembly of claim 1, wherein, described low electrical resistant material is for silver or contain a large amount of silver.

3. according to the heater assembly of claim 1 or 2, wherein, the length of described low electrical resistant material is at least 8mm.

4. according to claim 1,2 or 3 heater assembly, wherein, described contact is a power contact head.

5. heating vessel, it comprises a heater assembly, described heater assembly comprises an electric heater, described electric heater comprises a resistance heating trace that is layered on one deck dielectric substrate, this electric heater has an electric terminal position at least, this location-appropriate ground separates with heater tracks with one section material, the resistance value of this section material is significantly less than the heating rail material, described heater assembly comprises that also described spring contact is made or is installed on the spring leaf by a spring leaf with the contacted spring contact of described connecting point position.

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