FEED-THROUGH ELEMENT FOR APPLICATION IN A VACUUM APPARATUS; APPARATUS PROVIDED WITH SUCH FEED-THROUGH ELEMENTS AS WELL AS WIRE MATERIAL FORMED IN SUCH AN APPARATUS

Abstract: The invention relates to a feed-through element for application in a vacuum apparatus for the continous feeding through of wire-shaped material to be treated at least made up of a casing and a sealing element set up therein that is in contact with the surface or the wire-shaped material during feeding through, whereby the sealing element is formed by a drawing die (20) and whereby the casing is formed by a holder (21 ; 22) for the drawing die (20), at least a part of the holder (21 ; 22) being connected in a gastight way to a partition wall of the vacuum apparatus (1) and whereby the drawing die (20) and the holder (21 ; 22) act together in sealing relation (see figure 2).

Description: This invention relates to a vacuum apparatus for wire-shaped material having at least one vacuum chamber defined by end walls, adapted to receive wire-shaped material passing through said chamber so that the material may be treated under vacuum conditions. Such a vacuum apparatus is known from the French patent 2.315.645. A disadvantage of this French patent is that there is a certain clearance between the wire-shaped material to be fed through and the feed-through elements of this vacuum apparatus. This leads to unacceptable vacuum problems due to unsufficient sealing conditions of the feed-through elements. It is an object of the invention to provide a vacuum apparatus for wire-shaped material with improved feed-through elements. The vacuum apparatus according to the invention is characterized in that a feed-through element is disposed in an end wall, said feed-through element comprising a drawing die means for reducing the cross sectional area of said wire-shaped material as the material is passed therethrough, holding means for retaining said drawing die, means for providing a gas-tight seal between said holding means and said drawing die, and means for providing a gas-tight seal between said holding means and said end wall, at least one of said aforementioned means for providing a gas-tight seal being detachable, whereby said drawing die may be replaced to accomodate wire-shaped material of different size. By a drawing die means as mentioned hereinabove is understood a means, known in the wire-products manufacturing industry, having the shape of a bored element generally made of hardened special steel or ceramic material. Such a die is used to reduce the diameter of metal wire under elongation by drawing. It has been found that a drawing die which is common in the wire manufacturing industry makes an excellent sealing element in a vacuum apparatus of the feed-through type. As is well-known, the drawing die has a feed-through aperture with a diameter that is smaller than the outside diameter of the wire to be fed through so that excellent sealing is obtained. If such a drawing die is inserted in a holder at least a part of which is inserted in a gastight way in a partition wall, the drawing die itself and the holder furthermore acting together in sealing relation, an extremely well functioning feed-through element will be obtained. In particular, the feed-through element according to the invention is provided with a drawing die which causes a reduction not exceeding 2 % By reduction is in this case understood the quotient As regards the desired sealing action of the drawing die applied, it has been found that a reduction not exceeding 2 % generally suffices ; in practice, a reduction of approximately 1 % is also highly satisfactory. It has been found that if a feed-through element in the form of a drawing die is inserted at the end wall of the vacuum apparatus, there where the wire material leaves the apparatus, this drawing die will give evidence of a densifying action on the freshly deposited aluminium metal. The pores present are shut as it were by the drawing die, which will cause the final wire material to present a higher resistance to corrosion during use. In particular, sealing material is inserted between the drawing die and the holder of the feed-through element. A suitable form of sealing material is an O-ring, for instance. Advantageously, the holder of the drawing die of the feed-through element can be inserted in a partition wall of a vacuum apparatus so that it can be detached. This way, it can be arranged that when changing from one wire type to another wire type, the change being small, it is possible to simply place another drawing die inside the holder. The detachability of the holder also allows a complete holder exchange in the case of great changes requiring a drawing die of another size. In general, the vacuum apparatus according to the invention will be provided with a feed-through element at the entry of the apparatus and at the exit of the apparatus, whereby said feed-through element will comprise a drawing die means. In a vacuum apparatus according to the invention comprising a plurality of chambers connected to each other, the feed-through elements in the partition walls between any chambers of the apparatus according to the invention will comprise drawing die means. The invention will hereinafter be illustrated with reference to the drawing, wherein : Figure 1 shows a schematic section through an apparatus for carrying out a vacuum treatment and wherein one or more feed-through elements according to the invention have been inserted. Figure 2 shows a longitudinal section through a feed-through element according to the invention. In figure 1, a vacuum-treatment apparatus for wire-shaped material is indicated with general reference number 1. In this case, the apparatus consists of several chambers 2, 3, 4, 5 and 6. Feed-through elements 7 and 12 have been inserted at the beginning and end of the apparatus whilst there are also feed-through elements 8 up to and including 11 between different chambers. Each one of the chambers is connected to a vacuum source via an exit 13, 14, 15, 16 and 17. Generally, a so-called rough vacuum will be provided for instance in chambers 2 and 6 via connections 13 and 17, which is obtained by a pump with a very high pumping capacity creating a relatively low vacuum. The chambers 3 up to and including 5 are connected via their respective exits 14 up to and including 16 to vacuum sources that can create a high vacuum. In the apparatus herein described, at least the feed-through elements 7 and 12 will be formed by a feed-through element according to the invention ; the feed-through elements indicated with 8, 9, 10 and 11 may be formed by other feed-through elements although the feed-through elements according to the invention can be utilized. Figure 2 shows a drawing on an enlarged scale of a feed-through element according to the invention. The core of the feed-through element is the drawing die 20 that is inserted in a holder composed of 2 parts 21 and 22. The drawing die is retained between the holder parts 21 and 22 and is connected in a sealing way to the holder by means of O-ring 23. Either part 21 or part 22 of the holder can be connected in a gastight way to a partition wall of the apparatus. As indicated hereinbefore, this gastight connection is advantageously detachable so that it is possible not only to replace or to exchange the drawing die in the same holder but also to replace the complete holder by a holder which allows to fit a drawing die of another size.

Claims: A vacuum apparatus for wire-shaped material having at least one vacuum chamber defined by end walls, adapted to receive wire-shaped material passing through said chamber so that the material may be treated under vacuum conditions, characterized in that a feed-through element is disposed in an end wall, said feed-through element comprising a drawing die means (20) for reducing the cross sectional area of said wire-shaped material as the material is passed therethrough, holding means (21, 22) for retaining said drawing die (20), means (23) for providing a gas-tight seal between said holding means (21, 22) and said drawing die (20), and means for providing a gas-tight seal between said holding means (21, 22) and said end wall, at least one of said aforementioned means for providing a gas-tight seal being detachable, whereby said drawing die may be replaced to accommodate wire-shaped material of different size. A vacuum apparatus according to claim 1, characterized in that a feed-through element as set forth is disposed in each of an entry and an exit end wall. A vacuum apparatus according to claim 1 or claim 2, comprising a plurality of said chambers connected to each other, characterized in that a feed-through element is disposed in at least an entry end wall of a first chamber and in an exit end wall of a last chamber. A vacuum apparatus according to one or more of the claims 1 - 3, characterized in that a feed-through element is disposed between connecting chambers. A vacuum apparatus according to one or more of the claims 1 - 4, characterized in that said drawing die is shaped to reduce the cross-sectional area of the wire-shaped material by an amount not exceeding 2 %.

Inventors: COPPENS, WILFRIED, LIEVENS, HUGO
Applicants: N.V. BEKAERT S.A.
Application year: 1987
Main classification: C21D9
IPC codes: F16J15, C23C14, B21C3, B21C37, C21D9