GB2319950A - Electroplating a stainless steel electric heating plate to prevent corrosion - Google Patents
Electroplating a stainless steel electric heating plate to prevent corrosion Download PDFInfo
- Publication number
- GB2319950A GB2319950A GB9625414A GB9625414A GB2319950A GB 2319950 A GB2319950 A GB 2319950A GB 9625414 A GB9625414 A GB 9625414A GB 9625414 A GB9625414 A GB 9625414A GB 2319950 A GB2319950 A GB 2319950A
- Authority
- GB
- United Kingdom
- Prior art keywords
- base part
- track
- plating
- plate
- stainless steel
- 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.)
- Withdrawn
Links
- 229910001220 stainless steel Inorganic materials 0.000 title claims abstract description 19
- 239000010935 stainless steel Substances 0.000 title claims abstract description 16
- 238000005260 corrosion Methods 0.000 title claims abstract description 10
- 230000007797 corrosion Effects 0.000 title claims abstract description 10
- 238000009713 electroplating Methods 0.000 title claims abstract description 7
- 238000005485 electric heating Methods 0.000 title 1
- 238000010438 heat treatment Methods 0.000 claims abstract description 34
- 239000007788 liquid Substances 0.000 claims abstract description 16
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims abstract description 14
- 239000000758 substrate Substances 0.000 claims abstract description 12
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 7
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims abstract description 6
- 229910052737 gold Inorganic materials 0.000 claims abstract description 6
- 239000010931 gold Substances 0.000 claims abstract description 6
- 229910052709 silver Inorganic materials 0.000 claims abstract description 6
- 239000004332 silver Substances 0.000 claims abstract description 6
- 239000002537 cosmetic Substances 0.000 claims abstract description 5
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims abstract description 3
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims abstract description 3
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 3
- 239000011651 chromium Substances 0.000 claims abstract description 3
- 238000007747 plating Methods 0.000 claims description 18
- 239000000463 material Substances 0.000 claims description 16
- 238000000034 method Methods 0.000 claims description 16
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 239000004020 conductor Substances 0.000 abstract description 2
- DEXFNLNNUZKHNO-UHFFFAOYSA-N 6-[3-[4-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]piperidin-1-yl]-3-oxopropyl]-3H-1,3-benzoxazol-2-one Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)C1CCN(CC1)C(CCC1=CC2=C(NC(O2)=O)C=C1)=O DEXFNLNNUZKHNO-UHFFFAOYSA-N 0.000 abstract 1
- 229910052751 metal Inorganic materials 0.000 abstract 1
- 239000002184 metal Substances 0.000 abstract 1
- 229910000831 Steel Inorganic materials 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 102000002322 Egg Proteins Human genes 0.000 description 1
- 108010000912 Egg Proteins Proteins 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 210000003278 egg shell Anatomy 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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
- H05B3/78—Heating arrangements specially adapted for immersion heating
- H05B3/82—Fixedly-mounted immersion heaters
Landscapes
- Cookers (AREA)
- Surface Heating Bodies (AREA)
- Resistance Heating (AREA)
Abstract
An electric heater (forming for example the base of a kettle) comprises a plate made from 400 Series stainless steel with a resistive heating track on an electrically insulating substrate provided on one side. The other, liquid contacting, side of the plate is at least partially electroplated (with for example 2-5 ~m of nickel) to prevent corrosion. To give a good cosmetic finish and to reduce limescale adhesion, the plate surface may have been pretreated and/or the electroplating may be further plated with gold, silver or chromium (being, for example, less than 0.2 ~m thick). Also disclosed is an electric heater made from a metal plate with an insulating substrate and heating track, where an electric contact point on the heating track is plated with a conductor, this may be done through electroplating which could be done simultaneously with any electroplating of the plate.
Description
Electric Liquid Heating Vessels
The present invention relates to electric liquid heating vessels and in particular to such vessels having a base part made from stainless steel, and having a heating element provided on the underside of the base part.
Such vessels have been known for some time, and are normally provided with a traditional sheathed heating element bonded to the underside of the base. More recently, however it has been proposed to provide an element of the type comprising a resistive heating track provided on an electrically insulating substrate which is itself applied to the base part. Such "thick film" heaters and their methods of manufacture are well known in the art and need not, therefore, be described in greater detail here. They are, however, exemplified in Wo 96/18331, and WO 96/17497.
For reasons connected with their mechanical, thermal expansion and thermal conductivity properties, so-called 400 Series stainless steels have been used in such applications. Whilst it might be assumed that such steels would exhibit satisfactory corrosion resistance, it has been found that they are, in fact, susceptible to both pitting and stress corrosion when immersed in water. These effects are exacerbated by the repeated heating and cooling of the stainless steel.
The present invention seeks to overcome the above problems, and form a first aspect of the present invention there is provided a method of preventing corrosion of a liquid contacting surface of a base part of an electric liquid heating vessel, said base part being of a 400 Series stainless steel material and having on its underside a heating element of the type comprising a resistive heating track provided on an electrically insulating substrate which is itself applied to the base part, said method comprising electroplating the said surface.
From a second aspect, the invention also provides an electric liquid heating vessel having a base part of a 400 Series stainless steel material and having on its underside a heating element of the type comprising a resistive heating track provided on an electrically insulating substrate which is itself applied to the base part, a liquid contacting surface of the base part being electroplated.
The invention has the advantage not only of providing corrosion resistance, but also possibility of providing an attractive cosmetic finish to the inner bottom surface of the vessel.
The whole, or only a selected part of the surface may be plated, as required.
The base part may be a discrete manufactured component or may form part of a vessel manufactured from stainless steel. Indeed, in the latter case, the whole vessel may be electroplated, but this will, of course, add to the expense of manufacture. In the case of a discrete component the base part may form the entire base, or only a part of the base, of a vessel of stainless steel or some other material such as plastics.
Preferably the base part is in the form of a plate which forms the base of, or a part of the base of, the vessel. The plate may be completely planar, or have some other appropriate form, such as disclosed, for example in WO 96/18331. The base plate then effectively forms a heater which can be mounted in the base of the steel.
Such a heater is in itself novel, and from a further aspect, the invention provides an electric heater comprising a plate made from a 400 Series stainless steel, an electrically insulating substrate applied to one side of the plate, and an electrically resistive heating track applied to the insulating layer, wherein at least a portion of the other side of the plate is electroplated.
In a plating process, the surface to be plated forms a cathode in the plating circuit. In plating heaters as above, an appropriate electrical connection may be made to the liquid heating surface (for example through a knife contact or through a hole in the plate or base), and the surface then immersed in an appropriate plating solution. However, the insulating substrate provided on the plate ensures that there is no electrical connection between the resistive heating track and the stainless steel base part, so that the stainless steel may be electroplated without plating the track or indeed the insulating substrate. This considerably facilitates manufacture.
The plating material may be nickel, for example bright nickel, plated to a thickness of 2 to 3 Hm or possibly as thick as 5 ym. The nickel plating provides the stainless steel with good corrosion resistance.
A further layer of, for example, silver, chromium or gold may be applied to a thickness of, for example, less than 0.2 ym to give a required cosmetic finish.
The plated surface may be polished to give a high gloss and consequent low adhesion of limescale.
Prior to plating, the surface to be plated may be pretreated, for example polished to prepare for a particular, e.g. matt, eggshell or mirror, surface finish. However, if no such surface finish is required the electroplating process may be carried out on the unprepared stainless steel surface which will generally be covered to some extent by an oxide layer formed at the high temperature in the furnace during production of the element.
Whilst the invention above has been described in relation to plating the liquid contacting surface of the base, it may also be applied to selectively plating the other side of the base. For example, it may be desirable to provide a corrosion resistant, low electrical resistant contact point, any where on either side of the base to receive an earth contact.
In the preferred embodiment above, this may be achieved by leaving an opening in the electrically insulating substrate on the dry side of the base so that a material may be deposited there.
Furthermore, the invention may be applied to providing electrical contact portions on a thick film heater as discussed above.
In thick film heaters, the heating track may be provided with a protective overglaze to prevent oxidation and corrosion of the track material.
Typically, however, contact forming portions of the track are left uncovered to provide access thereto.
Although under the circumstances described above, these surfaces will not be plated as there is no electrical connection to the track, if these regions are made the cathode in a plating system, and the heater immersed in a suitable electrolyte contacts can be deposited electrolytically directly onto the track.
This is in itself a novel proposal which need not be applied solely to Series 400 stainless steels, and from a yet further aspect, the invention provides a method of manufacturing an electric heater of the type comprising an electrically resistive heating track applied to an electrically insulating layer provided on a metallic surface, wherein an electrical contact is electroplated onto a contact portion of the track.
The invention also provides an electric heater of the type comprising an electrically resistive heating track applied to an electrically insulating layer provided on a metallic surface, wherein a contact portion of the track is electroplated.
This method allows a wide variety of contact materials to be deposited. For example silver, gold or some other low resistance material, may be used.
The contact material could conveniently be deposited at the same time as the cosmetic finish as discussed above, or in a completely separate operation.
Further to the above, if, for any reason, it is desired to provide a low resistance section of track, this may also be achieved by overplating the track with a highly conductive material such as silver or gold.
From a yet further aspect, therefore, in very broad terms the invention provides an electric heater of the type comprising an electrically resistive heating track applied to an electrically insulating layer provided on a metallic surface, wherein a portion of the track is overplated with a low resistance material.
The invention is applicable to all 400 Series stainless steels, but may find particular application in 430S17, a material already used in the manufacture of heaters as discussed above.
It will be appreciated that the invention also extends to a base part for a liquid heating vessel produced in accordance with the invention, and to such a liquid heating vessel itself.
Claims (14)
1. A method of preventing corrosion of a liquid contacting surface of a base part of an electric liquid heating vessel, said base part being of a 400 Series stainless steel material and having on its underside a heating element of the type comprising a resistive heating track provided on an electrically insulating substrate which is itself applied to the base part, said method comprising electroplating the said surface.
2. An electric liquid heating vessel having a base part of a 400 Series stainless steel material and having on its underside a heating element of the type comprising a resistive heating track provided on an electrically insulating substrate which is itself applied to the base part, a liquid contacting part of the base part being electroplated.
3. A method or apparatus as claimed in claim 1 or 2 wherein the base part is a discrete component mountable in the base of the vessel.
4. An electric heater comprising a plate made from a 400 Series stainless steel, an electrically insulating substrate applied to one side of the plate, and an electrically resistive heating track applied to the insulating layer, wherein at least a portion of the other side of the plate is electroplated.
5. A method or apparatus as claimed in any preceding claim, wherein the plating material comprises nickel.
6. A method or apparatus as claimed in claim 5 wherein the thickness of the nickel plating is from 3 Hm to 5 Hm.
7. A method or apparatus as claimed in claim 5 or 6, wherein the base part or plate is subsequently plated with gold, silver or chromium on top of the nickel plating.
8. A method or apparatus as claimed in claim 7 wherein the thickness of the subsequent plating is less than 0.2 im.
9. A method or apparatus as claimed in any preceding claim wherein an electrical contact portion of the nonliquid contacting surface of the base part is plated.
10. A method or apparatus as claimed in claim 9 wherein said contact plating is deposited at the same time as a cosmetic plating is applied on the liquid contacting side of the base member.
11. A method of manufacturing an electric heater of the type comprising an electrically resistive heating track applied to an electrically insulating layer provided on a metallic surface, wherein an electrical contact is electroplated onto a contact portion of the track.
12. An electric heater of the type comprising an electrically resistive heating track applied to an electrically insulating layer provided on a metallic surface, wherein a contact portion of the track is electroplated.
13. A method or apparatus as claimed in any of claims 9 to 12, wherein the contact plating material is gold or silver.
14. An electric heater of the type comprising an electrically resistive heating track applied to an electrically insulating layer provided on a metallic surface, wherein a portion of the track is overplated with a low resistance material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9625414A GB2319950A (en) | 1996-12-06 | 1996-12-06 | Electroplating a stainless steel electric heating plate to prevent corrosion |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9625414A GB2319950A (en) | 1996-12-06 | 1996-12-06 | Electroplating a stainless steel electric heating plate to prevent corrosion |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9625414D0 GB9625414D0 (en) | 1997-01-22 |
| GB2319950A true GB2319950A (en) | 1998-06-10 |
Family
ID=10804071
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9625414A Withdrawn GB2319950A (en) | 1996-12-06 | 1996-12-06 | Electroplating a stainless steel electric heating plate to prevent corrosion |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2319950A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0967837A1 (en) * | 1998-06-25 | 1999-12-29 | Thermocompact | Heating element for food applications and manufacturing method |
| EP1018855A2 (en) * | 1998-12-30 | 2000-07-12 | Holding Company Aos | Gold-plated water heater element and method of making same |
| GB2352603A (en) * | 1999-07-23 | 2001-01-31 | Strix Ltd | Electric liquid heating vessels |
| EP1251192A2 (en) * | 2001-04-20 | 2002-10-23 | E.G.O. Elektro-Gerätebau GmbH | Manufacture process for heating element |
| WO2007068821A1 (en) * | 2005-12-16 | 2007-06-21 | Areva Np | Pressurizer heater for the primary cooling system of a pressurized-water nuclear reactor |
| EP2772563A1 (en) * | 2013-02-28 | 2014-09-03 | E.G.O. Elektro-Gerätebau GmbH | Method of manufacturing a heating device and heating device |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1191732A (en) * | 1966-05-18 | 1970-05-13 | Elpag Ag Chur | Treating Stainless Chrome-Nickel Steel Surfaces of Tubular Electrical Heaters |
| WO1996018331A1 (en) * | 1994-12-13 | 1996-06-20 | Strix Limited | Liquid heating vessels |
-
1996
- 1996-12-06 GB GB9625414A patent/GB2319950A/en not_active Withdrawn
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1191732A (en) * | 1966-05-18 | 1970-05-13 | Elpag Ag Chur | Treating Stainless Chrome-Nickel Steel Surfaces of Tubular Electrical Heaters |
| WO1996018331A1 (en) * | 1994-12-13 | 1996-06-20 | Strix Limited | Liquid heating vessels |
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0967837A1 (en) * | 1998-06-25 | 1999-12-29 | Thermocompact | Heating element for food applications and manufacturing method |
| FR2780263A1 (en) * | 1998-06-25 | 1999-12-31 | Thermocompact Sa | HEATING ELEMENT FOR FOOD APPLICATIONS, AND METHOD FOR MANUFACTURING IT |
| EP1018855A2 (en) * | 1998-12-30 | 2000-07-12 | Holding Company Aos | Gold-plated water heater element and method of making same |
| EP1018855A3 (en) * | 1998-12-30 | 2002-04-10 | Aos Holding Company | Gold-plated water heater element and method of making same |
| GB2352603A (en) * | 1999-07-23 | 2001-01-31 | Strix Ltd | Electric liquid heating vessels |
| EP1251192A3 (en) * | 2001-04-20 | 2004-04-07 | E.G.O. Elektro-Gerätebau GmbH | Manufacture process for heating element |
| EP1251192A2 (en) * | 2001-04-20 | 2002-10-23 | E.G.O. Elektro-Gerätebau GmbH | Manufacture process for heating element |
| WO2007068821A1 (en) * | 2005-12-16 | 2007-06-21 | Areva Np | Pressurizer heater for the primary cooling system of a pressurized-water nuclear reactor |
| FR2895206A1 (en) * | 2005-12-16 | 2007-06-22 | Framatome Anp Sas | HEATED ROD FOR PRIMARY CIRCUIT PRESSURIZER OF A PRESSURE WATER NUCLEAR REACTOR. |
| JP2009519453A (en) * | 2005-12-16 | 2009-05-14 | アレヴァ エヌペ | Heating rod for pressurizer in primary cooling system of pressurized water reactor |
| CN101336566B (en) * | 2005-12-16 | 2012-01-18 | 阿海珐核能公司 | Pressurizer heater for the primary cooling system of a pressurized-water nuclear reactor |
| US9730277B2 (en) | 2005-12-16 | 2017-08-08 | Areva Np | Pressurizer heater for the primary cooling system of a pressurized-water nuclear reactor |
| EP2772563A1 (en) * | 2013-02-28 | 2014-09-03 | E.G.O. Elektro-Gerätebau GmbH | Method of manufacturing a heating device and heating device |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9625414D0 (en) | 1997-01-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |