Coating processes – Direct application of electrical – magnetic – wave – or... – Induction or dielectric heating
Patent
1995-06-07
1997-09-09
Padgett, Marianne
Coating processes
Direct application of electrical, magnetic, wave, or...
Induction or dielectric heating
427431, 4274342, 4274345, 427598, 118623, 118405, 118429, 164493, 164471, H05B 602, B05D 118, B22D 1100, B05C 300
Patent
active
056654375
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a process and a device for carrying out the process for coating the surface of strip material, especially non-ferrous metal and steel strip, with a metal coating. In the process, the material is conducted without reversal of direction through a container holding the melted coating material that has, below the level of the melting bath, a passage duct, in which induction currents are induced in the coating material by an electromagnetic travelling field and produce, in interaction with the electromagnetic travelling field, an electromagnetic force for restraining the coating material.
DESCRIPTION OF THE PRIOR ART
Such a process and device for coating continuous strips is known from the SU Authorship Certificate 1 157/125. In order to prevent the molten coating material from flowing out through the passage duct located on the underside of the container, the principle of an induction pump is applied. In such pumps for delivering molten metal, the forces generated by induction are used to agitate the metal with the field and to supply the necessary pressure to the pump. By installing an induction pump of this type below the bath container and ensuring that the pressure produced in the duct by the induction pump equals the hydrostatic pressure of the molten coating material, it is possible to prevent the coating material from flowing out. To this end, the inductor is switched in such a way that the travelling field moves toward the container bottom, producing the restraining effect.
The interaction of the magnetic field with the currents induced in the molten coating material produces electromagnetic forces within the area of the inductors along the entire length of the duct. Because the electromagnetic forces produced in each cross-section along the duct add up, the pressure created by these forces increases along the duct in the direction of the container bottom. Theoretically, the outflow through the duct should be stopped at a length where the pressure created by the pumping action of the induction pumps is equal to the hydrostatic pressure in the container.
In practice, however, it has been shown that the electromagnetic effect in the passage duct follows a complicated pattern, because, as must be noted, the coating material is a liquid, the layers of which move relative to one another. Especially in flat, broad ducts, like those needed for the through passage of strip material, the electromagnetic forces in the duct cross-section are unevenly distributed and may drop to zero at the ends if the inductors are not designed so as to achieve the most even possible distribution of the forces.
In any case, this uneven distribution of the magnetic forces in the flow-out area in the passage duct of the container makes itself felt in eddies: in the center of the duct, the coating material moves in the direction of the travelling field, while in the side area, under the influence of the regular hydrostatic pressure from the coating material, it moves in the opposite direction. Because of the high current speed, the duct is subjected to increased wear.
SUMMARY OF THE INVENTION
The object of the present invention is, while eliminating the aforementioned shortcomings, to create a process and device of the generic type with which a quieting of the melt is achieved in the passage duct as well as in the container and with which a counterbalance is attained to a large extent between the hydrostatic and the electromagnetic forces.
To attain this object the inventive process includes superpositioning a constant direct or alternating current field onto the travelling field in the area near the contained. This-superposed field damps movement in the coating material. Directing a constant field opposite to the travelling field damps the electromagnetic forces, especially in the area of the container-side entrance to the passage duct, so that the unequal forces at this point are homogenized.
According to the invention, a device for carrying out the process which device h
REFERENCES:
patent: 2824021 (1958-02-01), Cook et al.
patent: 2834692 (1958-05-01), Tama
patent: 3483030 (1969-12-01), Clarke
patent: 3939799 (1976-02-01), Kanbara et al.
patent: 4904497 (1990-02-01), Lewis
patent: 5512321 (1996-04-01), Paramonou et al.
Patent Abstracts of Japan:JP2,298,247; Pub. Oct. 12, 1990; Kawamura et al. "Plating Method with Molten Metal".
Patent Abstracts of Japan:JP3,079,747; Pub. Apr. 4, 1991; Yasunaga et al. "Molten Metal Plating Apparatus".
Birger Boris L.
Foliforow Vladimir M.
Frommann Klaus
Haupt Werner
Moroz Anatolij I.
Mannesmann Aktiengesellschaft
Padgett Marianne
LandOfFree
Process and device for coating the surface of strip material does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process and device for coating the surface of strip material, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process and device for coating the surface of strip material will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-68053