CN201057675Y

CN201057675Y - Compound core MI heating cable

Info

Publication number: CN201057675Y
Application number: CNU2007200041416U
Authority: CN
Inventors: 赵放
Original assignee: 赵放
Current assignee: Wuxi Hengye Electric Heating Electrical Appliance Co., Ltd.
Priority date: 2007-01-29
Filing date: 2007-01-29
Publication date: 2008-05-07
Anticipated expiration: 2017-01-29

Abstract

A composite core MI heating cable is provided, which is composed of a metal protecting sleeve, a crystal magnesia powder, an outer layer of composite core and an inner core of composite core. In no need of investing regulating power, the utility model can be widely used for the MI heating cables of different lengths and power according to various needs, which not only makes heat load and current density designed rationally to ensure service life, but also saves materials to reduce waste.

Description

Composite core MI heating cable

The utility model relates to a kind of MI heating cable with " composite core ", especially can be widely used in various length differences, the different MI heating cable of power.

Technical field:

At present, known MI heating cable is the inorganic heating cable of high temperature that develops into by at mineral insulated cable or MI fireproof cable structural improvement.It makes 1～6 heat generating core cross section by electrothermal alloys such as copper, nickel chromium triangle, constantan, siderochrome aluminium is that circle is distributed on and determines to fill in the circle metallic sheath in the middle of the magnesium oxide cross section.Its certain-length one or both ends are imposed voltage produce Joule heat by the heat generating core electric current.Patent documentation CN1110862A " PTC flexible metal heating cable " is though possess all characteristics of narration, and it can't be widely used in the purposes in the different various places of various length differences, power.Mainly contain two serious defectives: 1. the supply voltage for the MI heating cable of all lengths, various power has nothing in common with each other, and is restricted with the 380V/220V power-frequency voltage, as can cause big cost investment waste with voltage controller power source.2. can not determine rationally because of heat load and current density, can cause burning out or waste of material that kind that therefore have to limited selection electrothermal alloy is as nickel chromium triangle, siderochrome Lv, Opinions-Pictures copper, copper etc.

Background technology:

The purpose of this utility model provides a kind of composite core MI heating heating cable, and it can not only possess above-mentioned PTC flexible metal heating cable characteristics, and is fit to various length differences, the different heating cable of power.

Summary of the invention:

Order of the present utility model be achieved in that with the basis of known MI heating cable manufacturing process on, at first make " composite core ".Above-mentioned various electrothermal alloys and all kinds of electric resistance alloy are enlarged the selection electrical resistivity range from copper 0.0179 Ω mm ²/ m～iron nickel aluminium OCr27Ni17A1M02 1.53 Ω mm ²/ m, get a kind of definite resistivity and the oval bar of electrothermal alloy of diameter, its endoporus of pipe electrothermal alloy of another kind of resistivity of determining and equal length is identical with the former, be enclosed within above it, form real core stock, is that drawing-down is elongated with drawbench by die orifice, the drawing-down again of will annealing is elongated, repeated multiple times is passed through die orifice, tentatively reach the outer and composite core inner core of composite core of the composite core of diameter and expectation resistance value, composite core is through in the middle of the metallic sheath, and evenly fully fill the crystal magnesium oxide powder in the space between both, also can open-cell sintered cylinder magnesium oxide joint string on composite core, connect and go here and there again in the metallic sheath centre together, make real core body and form real core body each other.And then elongate by die orifice drawing-down together with drawbench, the drawing-down again of annealing is elongated, and repeated multiple times reaches the product diameter and needs resistance value by die orifice, has formed composite core (the outer and composite core inner core of composite core) simultaneously.The resistance value that has had required composite core to need has just found the rated voltage such as the 380V/220V that are fit to easily, need not invest voltage controller power source, has just obtained performance number or rice performance number.And heat generating core diameter that can reasonable basis determines surface thermal load and current density, promptly do not use to burn out and do not produce waste material, guaranteed useful life, can extensively select various electrothermal alloy kinds.

Adopt such scheme, just can be widely used in various length differences, the different heating cable of power.Below in conjunction with drawings and Examples the utility model is further specified.

Description of drawings:

Fig. 1, Fig. 3, Fig. 5 are respectively the outline drawings of a core, two cores, three core composite core MJ heating cable.

Fig. 2, Fig. 4, Fig. 6 are respectively the side views of a core, two cores, three core composite core MI heating cable.

Among the figure: 1. outer 4. composite core inner cores of metallic sheath 2. magnesia powders 3. composite core.

Concrete enforcement:

One single core composite core MI heating cable is arranged in Fig. 1,2, at first get the long Φ 5mm of a 2m round bar constantan, resistivity 0.48 Ω mm ²/ m and the long Φ 8 * 1.5mm of a 2m siderochrome aluminium OCr27Ni17A1M02 pipe are enclosed within above the round bar equally long, form by " real core stock ", elongate by the die orifice drawing-down with drawbench, the drawing-down again of annealing is elongated, repeated multiple times is passed through die orifice, tentatively reach Φ 7.5mm and about 0.05 Ω, seal in a long 1Cr19Ni9Ti of 2m then; In the centre of Φ 28 * 3mm stainless steel pipe, each other with stainless steel tube in distance evenly equate, and in the space between both evenly fully filling expire an integral body of crystal magnesium oxide powder.Above-mentioned completed " integral body " is elongated after the annealing drawing-down again with drawbench by die orifice drawing-down together elongates, it is long to carry out repeatedly crossing about 50m repeatedly, external diameter Φ 4.6mm, composite core Φ 1.5mm, resistance value 28 Ω can directly adopt industrial 380V need not invest voltage controller power source, every meter heating power 103W/m, can be used to be no more than 300 ℃ of long-term continuous operations, its surface thermal load 0.7W/cm ², current density 13.6A/mm ², the material of employing and useful life are all more reasonable, have adopted composite core to obtain effect preferably.Below roughly the same, can make Fig. 3, Fig. 4 two cores and Fig. 5 and Fig. 6 three core composite core MI heating cable respectively.

Claims

1. composite core MI heating cable, form by metallic sheath, crystal magnesium oxide powder, composite core skin and composite core inner core, composite core is made up of round bar electrothermal alloy and pipe electrothermal alloy, the round bar diameter is identical with the pipe endoporus, both resistivity differences, pipe is enclosed within above the round bar, preliminary elongation drawing-down, in the middle of going here and there then together in metallic sheath, evenly fill the crystalline oxides insulation, form " integral body ", use drawing process, elongate through drawing-down repeatedly and to reach external diameter and need resistance value, it is characterized in that: composite core is made of composite core inner core and composite core skin.

2. composite core heating cable according to claim 1 is characterized in that: the composite core inner core of composite core and composite core skin are to make with the different resistivity electrothermal alloy.

3. composite core heating cable according to claim 1 is characterized in that: composite core inner core and composite core skin through integral body repeatedly drawing reach the composite core of resistance value.