Coating apparatus – Immersion or work-confined pool type – Work extending through pool-confining wall area
Patent
1996-11-12
1998-06-30
Czaja, Donald E.
Coating apparatus
Immersion or work-confined pool type
Work extending through pool-confining wall area
118423, 118429, 427 96, 427 98, 4274301, B05C 302
Patent
active
057727651
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention generally relates to an apparatus for the immersion processing of moving workpieces through a bath. More particularly, the present invention relates to a seal arrangement at the ends of an immersion processing chamber through which a relatively flat workpiece, such as a printed circuit board, can enter and exit the immersion chamber with a minimal leakage of the bath fluid.
EP-A-0 421 127 discloses a device for processing printed circuit boards, in the case of which the individual printed circuit boards are conveyed continuously in a vertically hanging position on a horizontal transport path through successively arranged processing baths. The transport of the printed circuit boards through the processing baths which are accommodated in processing cells, is facilitated by brackets arranged on endlessly revolving drives. Those brackets, in the case of electrochemical processing, at the same time also make the cathodic contact with the printed circuit boards. Vertical slots for the passage of the printed circuit boards are located in the end walls of the processing cells, seals which are designed as a brush seals or strip brush seals being provided in the passage region. The individual processing cells are arranged in catchment troughs, from which the bath liquid which is caught is continuously fed back into the assigned processing cells with the aid of appropriate pumps. A continuous feedback of the bath liquid also makes it possible to maintain a constant level in the individual processing cells here.
U.S. Pat. No. 4,401,522 discloses a device for the electrolytic processing of printed circuit boards, in which vertically arranged roller pairs act as seals to the vertical slots in the end walls of the processing cells. The rollers, which are composed of an elastic material, are provided as roller pairs which are pressed against one another in a sprung manner and are driven at a speed matched to the transport speed of the printed circuit boards passing through. An object of the invention in the case of a device for the processing of flat workpieces, is to improved an improved device which enables effective sealing of the vertical slots in the end walls of the processing cells for the passage of the workpieces, using simple means, and of minimizing the escape of bath liquid in the region of the slots.
SUMMARY OF THE INVENTION
The present invention achieves the aforementioned object by providing an improved device for immersion processing of flat workpieces, such as printed circuit boards. The device is for use with a manufacturing arrangement in which the workpieces are held in a vertical position and conveyed along a horizontal transport path. To this end, the device includes an immersion processing cell for containing a processing bath fluid. The processing cell is formed by a trough. The processing cell has a pair of opposed vertical end walls, and each of these end walls has a vertical slot disposed therein to accommodate a respective entry and exit through which the workpieces may be conveyed, immersing the workpieces in the bath as they are conveyed through the processing cell. Each of the slots has a pair of seals which permit the workpiece to pass into or out of the slot between the respective pair of seals, while minimizing loss of the bath fluid through the slot. Each of the seals is cylindrical in shape, and at least one cylindrical element. The seals are free and movable relative to the processing cell and disposed generally vertically, but the seals are retained. Fluid pressure from the bath acts against the seals so that the seals are pressed toward one another and against the respective end wall.
In an embodiment, an end chamber is formed in the each of the end walls to retain the respective pair of seals in a generally vertical position proximal to said slot, but in a freely moveable manner relative to the end wall. Each end chamber is wider than the respective slot, which bisects the chamber.
The advantages which are achieved by the inventi
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Colaianni Michael P.
Czaja Donald E.
Siemens S.A.
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