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
  • H05B3/20—Heating elements having extended surface area substantially in a two-dimensional [2D] plane, e.g. plate-heater
  • H05B3/22—Heating elements having extended surface area substantially in a two-dimensional [2D] plane, e.g. plate-heater non-flexible
  • H05B3/28—Heating elements having extended surface area substantially in a two-dimensional [2D] plane, e.g. plate-heater non-flexible heating conductor embedded in insulating material
  • H05B3/30—Heating elements having extended surface area substantially in a two-dimensional [2D] plane, e.g. plate-heater non-flexible heating conductor embedded in insulating material on or between metallic plates
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B3/00—Ohmic-resistance heating
  • H05B3/10—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
  • H05B3/18—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor the conductor being embedded in an insulating material

Definitions

• the present invention relates to heating elements consisting of a composite system made of a metal substrate, an electrically insulating base glass layer applied thereon, metallic conductors and a chemically resistant cover glass layer.
• the heating conductor tracks are covered by suitable measures, e.g. protected from contact by foaming plastics or by metal grids. Nevertheless, such surface heating elements do not meet the safety requirements in some countries.
• the heating capacity is also limited to around 100 ° C due to the necessary design-related limitation of the surface temperature.
• the present invention now relates to a surface heating element consisting of a metal substrate coated with an insulating glass and metallic resistance tracks applied thereon, which is characterized in that the insulating glass is a calcium-aluminum-boron-silicate glass and that there is a further layer over the metallic resistance tracks Mixture of a zirconium phosphate glass and a boron-titanium enamel.
• the insulating glass layer consists of an alkali-free calcium alumo-borosilicate glass (29-34% by weight CaO, 7-10% by weight X Al 2 O 3 , 43-48% by weight XB 2 O 3 , 8- 15% by weight SiO 2 , 1-2% by weight MgO).
• the insulating glass After baking on steel substrates, it can withstand thermal loads of up to 400 ° C without any significant loss in electrical volume resistance.
• the insulating glass In contrast to classic enamelling with an irregular bubble structure that can hardly be influenced, the insulating glass is characterized by an even, fine, statistically distributed bubble structure when it is baked.
• the insulating glass layer according to the invention can be applied to cold-rolled steel sheet coated with conventional basic enamels or also directly to decarburized steel sheet.
• a clay-free slip of the insulating glass is applied to the steel panels treated in this way by dipping or spraying, the metallic heating conductor is placed on the still wet layer, avoiding air pockets, dried together and baked in the usual manner at 820 to 840 ° C.
• the thermal shock resistance of the composite insulating glass, heating conductor, top layer can be significantly improved by using a combination of a glass rich in zirconium phosphate, which contains Ba 2 Zr 2 Si 3 0 12 crystals, with titanium white enamels with Ti0 2 excretion.
• Suitable zirconium phosphate glasses have the following composition:
• a zirconium phosphate glass component with the following oxidic composition has proven particularly suitable:
• the proportion of the zirconium phosphate glass in a mixture with the commercially available titanium white enamel is about 35 to 55% by weight, preferably over 45% by weight.
• the titanium white enamels are known and customary types of enamel (see e.g. A.I. Andrews, Porcelain Enamels, p. 277).
• Decarburized steel according to DIN 1623, part 3, quality ED 3 is degreased in the usual way and pickled with 8% sulfuric acid at 70 ° C until the weight loss is 40 g / m 2 on both sides. It is then rinsed with water and nickel-plated by immersing it in nickel sulfate solution (1 g of nickel iqm 2 ) .
• the icing glass slip is applied on both sides with the aid of a spray gun so much that the later baked layer becomes 180 ⁇ m thick on one side and about 70 ⁇ m thick on the other side.
• the coating on both sides prevents warping.
• the metallic heating conductor is placed on the still wet layer on the thickly coated side, avoiding air bubbles, dried together and at 820 ° C for 6 min. branded.
• a mixture of 15.6 g quartz flour, 19.5 g sodium tripolyphosphate, 1.8 g potassium carbonate, 7.5 g titanium dioxide, 20.5 g zirconium silicate, 18.7 g monobarium phosphate, 10.9 g Monopotassium phosphate, 9.7 h of silica fluoropotassium was at 1400 ° C in a chamotte crucible for 25 min. melted, the temperature within a further 10 min. lowered to 1250 ° C and then quenched in water.
• the granules thus obtained and a commercially available titanium white enamel were ground to a slip in a ball mill after the following mill offset:

Landscapes

• Resistance Heating (AREA)
• Glass Compositions (AREA)
• Surface Heating Bodies (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

Family

ID=6283330

Family Applications (1)

Country Status (7)

Cited By (4)

Families Citing this family (27)

Citations (7)

Family Cites Families (7)

• 1985
  • 1985-10-11 DE DE19853536268 patent/DE3536268A1/de not_active Withdrawn
• 1986
  • 1986-09-25 MX MX003847A patent/MX168410B/es unknown
  • 1986-09-26 US US06/912,446 patent/US4713530A/en not_active Expired - Fee Related
  • 1986-10-06 JP JP61236366A patent/JPS6293884A/ja active Pending
  • 1986-10-08 AT AT86113934T patent/ATE48057T1/de not_active IP Right Cessation
  • 1986-10-08 DE DE8686113934T patent/DE3667004D1/de not_active Expired
  • 1986-10-08 ES ES86113934T patent/ES2012041B3/es not_active Expired - Lifetime
  • 1986-10-08 EP EP86113934A patent/EP0222162B1/fr not_active Expired

Patent Citations (7)

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