Coating apparatus – With vacuum or fluid pressure chamber
Reexamination Certificate
1999-04-20
2001-07-17
Edwards, Laura (Department: 1734)
Coating apparatus
With vacuum or fluid pressure chamber
C118S308000
Reexamination Certificate
active
06261366
ABSTRACT:
FIELD AND BACKGROUND
The present invention concerns a suction device for a double-point coating system.
In double-point coating, first a paste is applied to a fabric web in dots at even intervals and a powder is then sprinkled over it, by means of which the paste points or bumps and the areas in between them are at least partially covered with the powder.
However, the goal of double-point coating is to produce fabric webs that have, at least on one top side, individual nops or dots made of a paste and a powder sprinkled on them connected to the paste, so that the fabric web stays uncoated in the areas between the individual nops or dots. Therefore, suction devices are used that suck loose powder off the fabric web.
A proven suction device is known in which a fabric web is run under a powder-suction element which sucks off the loose powder. Two suction nozzles are arranged in the direction in which the fabric web moves, before and after the powder-suction element, that suck down the fabric web from underneath and thus provide tension on the fabric web. A beater roller is arranged in the direction of movement in front of the powder-suction element, said beater roller making a beating motion on the bottom of the fabric web, thus throwing the powder up before it is caught by the powder-suction element and sucked off for further use or disposal.
Although this double-point suction device yields satisfactory results, the arrangement of the paste/powder points has nonetheless often been shown to be uneven and, in serious cases, the powder even clogs the fabric. This is especially true in the case of elastic materials. The reason for this is that the fabric webs in the double-point suction device are subjected to tension, which stretches the fabric.
The problem of the present invention is to create a double-point suction device in which the fabric web is subjected to no tension or subjected only to slight tension.
BRIEF SUMMARY
This problem is solved by a double-point suction device with the features exemplified herein below.
By using rotating, actively driven suction rollers instead of fixed suction nozzles, the fabric web may be moved through the double-point suction device without tension.
In one preferred embodiment, a suction roller is arranged under a powder-suction element having a suction channel. Preferably, this suction roller has at least one blow nozzle in order to stir up the powder or keep it suspended.
Advantageously, at least one other suction roller is arranged in front of the powder-suction element, in relation to the direction of movement of the fabric web. To prevent the suction roller from sticking, there is a squeegee or at least one blow nozzle to remove powder deposits on the suction roller. The advantage of the blow nozzle is that it may be arranged inside the suction rollers in order that the suction holes in the roller may be cleaned by being blown out.
REFERENCES:
patent: 1635317 (1927-07-01), Feeney
patent: 3013938 (1961-12-01), Justus et al.
patent: 4571351 (1986-02-01), Schaetti
patent: 5094886 (1992-03-01), Bogardy
patent: 5225140 (1993-07-01), Hayashikoshi et al.
patent: 5360481 (1994-11-01), Ludwig
patent: 6007632 (1999-12-01), Reis et al.
Dubs Max
Holdener Hubert
Edwards Laura
Schaetti AG
Weingarten, Schurgin Gagnebin & Hayes LLP
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