Wire Coating Process And Apparatus

Abstract

The present apparatus is for coating one or more strands with fusible particles, which strands are fed in a continuous manner into the open top of a chamber having a fluidized bed of coating particles therein and which strands are heated in their travel to said fluidized bed whereby said particles are fused on said strands building up a coating on the strands which are fed from the open top of said chamber each through an air bearing guide to a heater, cooler and then to a take-up roll therefor.

Description

The present invention is related to apparatus for coating strand material with fusible coating material and is an improvement thereon.

The principal object of the present invention is to provide an apparatus for coating one or more strands continuously, economically and at relatively high speed through an open top chamber without sealing devices for the passage of the strands into and from said chamber.

A further important object of the invention is to provide an apparatus for coating multiple strands of material simultaneously which strands can be of the same or different materials and cross-sections or of uniform or non-uniform cross-section.

Another important object of the invention is to heat the strands within a fluidized bed in an open top coating chamber using heat from cooling means for already coated strands to prevent heat losses and which strands upon being coated are guided through a non-contacting stabilizer which removes non-fused coating particles from the strands.

Further objects of the invention will be in part obvious and in part pointed out in the following detailed description of the accompanying drawings, in which,

FIG. 1 is a top plan view of an apparatus according to the present invention.

And FIG. 2 is a longitudinal sectional view taken on line 2--2 of FIG. 1.

Referring now more particularly to the accompanying drawings in which like and corresponding parts are designated by the same reference characters, numeral 1 indicates an axle on which are rotatably mounted a plurality of rolls 2 of strand material 3 to be coated. As indicated in FIG. 1 there are a plurality of rolls 2 with elements for coating and conveying each strand 3 as one or more such arrangements can be used and as they are all the same only one is described herein.

That is, each strand 3 passes through superposed rollers 4, 5, 6 and 7 for straightening the strand to remove undesirable curves therein.

Each straightened strand 3 passes over a guide roller 8 and then downwardly alongside an end wall 9 of the coating chamber. Said chamber also has a pair of side walls 10, and upwardly slanting end wall 11 with end walls 9 and 11 connecting said side walls 10. End wall 11 has a vertical bottom portion 12. A bottom 13 extends across and is attached to said end and side walls which are unconnected at their tops providing an open top 14 for said chamber. A porous plate 15 extends from end wall 9 to the lower portion 12 of end wall 11 and to said side walls 10.

A guide roller 16 is rotatably mounted above porous plate 15 adjacent end wall 9 with strand 3 passing underneath roller 16 and then on an upward slant through a heater 17 preferably of a focused infrared type. As the strand passes through the heater 17, said strand is heated to a temperature above the fusion temperature of the coating particles 18 in said chamber. The strand 3 leaving said heater pass through the particles 18 which touch the strand and are fused thereto whereby a continuous uniform coating is built up on the heated strand 3.

As the coated strand 3 leaves the coating particles 18 it passes through, but does not touch a funnel shaped bearing device 19 into the bore of which high pressure air is passed from tube 20 connected to a source (not shown) of air under pressure. Said device 19 is necessary when strand 3 is either fine or has low tensil strength as said bearing device serves to stabilize the strands radial motion. Stronger strands can be stabilized by applying tension thereto as by keeping the strand taut, such as by adjusting the position of rollers 16 and 23 relative to one another.

After the coated strand leaves the bearing device 19, it passes through a post cure heater 21, which can be a tubular heater similar to heater 17 and said heater 21 serves to complete the curing of the coating material and/or to smooth its surface. The use of a post cure heater 21 depends on the coating materials properties.

The coated strand then passes through a cooling plenum 22 where high velocity air is passed along the strand to remove the heat of fusion therefrom.

After the cooling plenum 22, the strand 3 is then passed over an adjustably mounted guide roller 23 and then to a take-up coil 24 of said strand. Coil 24 is attached to an axle 25 driven in a counter clockwise direction by means (not shown) for drawing the strand 3 from roll 2 to roll 24. Roll 24 can be removed from axle 25 when desired for its end uses.

A blower 26 has its air admission opening connected by tube 27 to plenum 22 for drawing air through said plenum, which air is heated by the heated coated strand 3 and goes from blower 26 through the leg 28 of an inverted T-tube to its cross-head 29 which has air control valves 30 and 32 on its ends. A tube 31 connected to a further source of air under pressure (not shown) is attached to valve 30 while valve 32 is connected to tube 34 opening in the space between bottom 13 and porous plate 15 of said chamber. Tube 31 can be an air exhaust outlet.

An electric heater 33 is positioned in tube 34 for heating air passing therethrough.

The heated air from tube 34 passes upwardly through porous plate 15 and heats the coating particles 18 above said plate to a temperature just below their tacky point. Heating the coating particles 18 enables a lower power consumption by the strand heater 17 and also permits the strands to move at a higher velocity.

The term "strand" as used herein is to be considered a generic term for metallic wire, plastics, textiles and other elongated materials. Material of irregular cross-section can be coated in the present apparatus by using properly designed guide rollers 16 and 23. For example, barbed wire, rope, ribbon, perforated strip, cable or other strand elements can be coated in the present apparatus or various combinations of strands can be coated at the same time. Thus for example, the strands 3 can be various size wires and the maximum number of strands is dependent only on the practical size of the strand supply and take-up equipment. When multiple wire are being coated, a different coating thickness may be obtained for each wire 3 depending on the speed of travel of the wire, for example about 500 to 600 feet per minute, and the temperature setting for heaters 17 and 21.

The coating particles 18 are moved by the air from porous plate 15 and their height is controlled by valve 32. Such particles may be any of the thermoplastic and thermosetting coating materials. Descriptions of examples of such materials and their use are well known and U. S. Pat. No. 3,019,126 is referred to therefore only as an example thereof.

Claims

We claim:

1. An apparatus for coating strand material comprising an open top chamber, a porous plate extending across the interior of said chamber providing a bottom section and an open top section for containing coating material, means for supplying air under pressure into said bottom section whereby said air passes through said porous plate to said coating material, a guide roller in said top section, a heater in said top section whereby a strand of material can be fed into said chamber open top to said roller, through said heater to said coating material to be coated thereby and through the open top of said chamber.

2. An apparatus for coating strand material comprising an open top chamber for containing coating material, means for supplying air under pressure to said chamber below and into the coating material, a guide roller in said chamber, a heater in said chamber whereby a strand of material can be fed into said chamber open top to said roller, through said heater, to and through said coating material to be coated thereby and through the open top of said chamber, a second roller positioned exteriorily of said chamber and above the open top of said chamber for receiving and guiding the coated strand material, a funnel shaped guide positioned between said heater and said second roller and means for supplying air under pressure within said guide providing an air bearing guide for the coated strand material passing therethrough from said heater.

3. An apparatus for coating strand material comprising an open top chamber for containing coating material, means for supplying air under pressure to said chamber below the coating material, a guide roller in said chamber, a heater in said chamber whereby a strand of material can be fed into said chamber open top to said roller and through said heater and coating material to be coated thereby and through the open top of said chamber, a second roller positioned exteriorily of said chamber and above one end of the open top of said chamber for receiving and guiding the coated strand material, a third guide roller positioned exteriorily of said chamber above the open top thereof on an opposite end of said chamber to said second roller, means for supporting a roll of strand material to be fed to said third roller, and means positioned between said supporting means and said third roller capable of straightening the strand material fed from said roll supporting means.

4. An apparatus for coating strand material comprising an open top chamber for containing coating material, means for supplying air under pressure to said chamber below the coating material, a guide roller in said chamber, a heater in said chamber whereby a strand of material can be fed into said chamber open top to said roller and through said heater and coating material to be coated thereby and through the open top of said chamber, a second roller positioned exteriorily of said chamber and above one end of the open top of said chamber for receiving and guiding the coated strand material, a third guide roller positioned exteriorily of said chamber above the open top thereof on an opposite end of said chamber to said second roller, means for supporting a roll of strand material to be fed to said third roller, a plurality of said roll supporting means, rollers and said heater being positioned in series thereof laterally of and in said chamber whereby a plurality of strands can each be fed between a pair of said rolls over one of said third, first and second roller and through one of said heaters.

5. An apparatus for coating strand material as claimed in claim 2 including a tubular member positioned between said guide and said second roller and means for passing air through said tubular member for cooling coated strand material from said guide passing through said tubular member.

6. An apparatus for coating strand material as claimed in claim 5 including a tube opening into the bottom of said chamber and said air passing means consisting of a blower connected to said tubular member and said tube.

7. An apparatus for coating strand material as claimed in claim 6 including a heater in said tube.

8. An apparatus for coating strand material as claimed in claim 6 including an air valve interconnected in said tube.

9. An apparatus for coating strand material as claimed in claim 6 including a porous plate extending across the interior of said chamber above said tube.

10. An apparatus for coating strand material as claimed in claim 2 including a heater between said funnel shaped guide and said second roller for receiving the coated strand therethrough.