Description:
This invention relates to apparatus for removing treating liquids from treated metal strip and, more particularly, to such apparatus wherein air or gas under pressure is utilized to remove the treating liquid.
In the copending patent application of Singleton et al, U.S. Ser. No. 858,284, filed Sept. 16, 1969, now U.S. Pat. No. 3,620,561 and entitled STRESS RELIEVING APPARATUS AND METHOD, there is disclosed an apparatus for stress relieving a metal wire product after it has been immersed in a molten metal bath. One aspect of the present invention constitutes an improved wiper apparatus for a metal strip product as it emerges from the treating bath.
The apparatus of the present invention may be used not only in treating aluminum containing material, but also other metal products such as brass and steel wire, both round and flat.
The invention is also applicable to the use of other constituents or compositions for the treating bath. Thus oil and water may be used as the treating liquid in addition to the molten metal bath compositions which are disclosed in the aforesaid patent application of Singleton et al Ser. No. 858,284.
While the invention was originally devised to be used on flat products, such as flat wire, foil and sheet products; it has been found that the invention works equally well on round products such as round wire.
In accordance with the teaching of the present invention, a metal strip product is immersed in a liquid treating bath and inserted into the wiper apparatus of the present invention as it emerges from the liquid treating bath. The wiper assembly of the instant invention may be positioned either vertically or horizontally. The metal to be wiped is inserted sequentially through an entrance port, an inlet orifice, an air or gas treating chamber, and an outlet orifice.
While both the outlet and inlet orifices conform substantially to the cross section of the metal strip product, the outlet orifice is made slightly smaller than the inlet orifice so as to establish an air or gas flow counter to the direction of feed of the metal strip product, i.e., toward the inlet orifice. The treating gas may be air or in some instances an inert gas, such as Argon.
In accordance with actual tests, molten lead and molten lead-bismuth (50/50 on a volumetric basis) has been wiped from flat aluminum wire. Also water and water-oil emulsions have been wiped from aluminum, brass and steel wire, both round and flat. With the exception of the water-oil emulsions, the metal was wiped thoroughly. On the water-oil emulsions, a thin film of oil remained, and this is deemed to be desirable characteristic in providing lubrication since the water-oil emulsions are generally used in conjunction with drawing or rolling operations.
The volume of air or gas consumed is very small by virtue of the close tolerances between the sides of the orifices and the surfaces of the metal being wiped. Argon gas was used to wipe molten metal from aluminum in order to prevent further oxidation, at a maximum flow of 15 cfh (cubic feet per hour) at a line pressure of 25 psig (pounds per square inch gauge), with flat wire speeds of up to 600 feet per minute. Respooling difficulties prevented faster rates of feed.
In wiping water and water-oil emulsions from flat wire at 600 feet per minute, air was used in conjunction with a line pressure of 25 psig. Water and water-oil emulsions were also used to wipe round wire, 24 B & S gauge, using a line pressure of 25 psig with wire speeds up to 1,350 feet per minute.
The inherent advantages and improvements of the present invention will become more readily apparent upon considering the following detailed description of the invention and by reference to the drawings in which:
FIG. 1 is an elevational view, fragmentary in nature, illustrating the use of the wiper apparatus of the present invention;
FIG. 2 is an elevational view of the wiper apparatus of FIG. 1, drawn to an enlarged scale, and taken in vertical cross section;
FIG. 3 is an exploded perspective view of the wiper apparatus of FIG. 2, drawn to a further enlarged scale; and,
FIG. 4 is a perspective view of a modified orifice plate for use with the wiper apparatus of the present invention.
Referring now to FIG. 1 of the drawings, there is illustrated a wiper apparatus indicated generally at 10 for use in wiping a metal strip product 12 which may be wire, foil or strip sheet material. The wiper apparatus 10 is used in conjunction with apparatus of the type described in the copending patent application of Singleton et al Ser. No. 858,284, and includes a feeding apparatus indicated generally at 14. The metal strip product 12 is shown to have a portion thereof immersed in a treating liquid 16 which may be a molten metal bath such as used in connection with the Singleton et al apparatus or instead may be a water or water-oil emulsion.
The metal strip product 12 is illustrated to be entrained over a large guide roller 18 and passed through a holder 20 for an input stripper means such as is disclosed in the aforementioned patent application. The metal strip product 12 passes between guide rollers 22 mounted on a pair of plate members 24 and 26 and is then withdrawn from the treating bath through the wiper apparatus 10 in a manner more clearly shown in FIG. 2.
Upon emergence from the wiper apparatus 10, the metal strip product 12 passes over a series of guide rollers 30 and drive roller means 32 which may be mounted on mounting plate 28. Thermocouple means are indicated generally at 34 whose thermocouple wires 36 are placed in a desired proximity to the metal strip product as it is immersed in the treating liquid 16 so as to measure the temperature thereof when the treating liquid is a molten metal. A bottom cross plate member 38 is provided with a suitable locking member and locking handle 40 in order to adjust the relative position of the vertical holder members 41.
Reference to FIG. 2, illustrates the wiper apparatus in greater detail. Thus a bottom cover plate is illustrated at 42 having a central aperture 44 therein. The bottom cover plate 42 is directly beneath an entrance port body 46 which also has a central aperture 48 axially aligned with the central aperture 44 in the bottom plate. Bolts 50 extend through the bottom cover plate and entrance port body 46 into an air or gas distributor body 52.
Reference to FIG. 3 illustrates the provision of a recess 54 which may be a milled slot in the entrance port body 46 so as to receive therein an entrance orifice plate 56 having an entrance orifice 58 located substantially centrally thereof. The air or gas distributor body 52 is provided with a large central bore 60 which is in vertical alignment with the central apertures 48 and 44 in the entrance port body and bottom plate cover, respectively. The air or gas distributor body 52 is provided with threaded air or gas inlets 62 and 64 into which are received conduits such as conduits 66 in FIGS. 1 and 2 secured by means of a nut 68. In this manner, air or gas from a suitable source, not shown, are admitted under positive pressure into the chamber provided by the central bore 60 in the air or gas distributor body 52.
Referring again to FIG. 3, there is illustrated a recess 70 which may be a milled slot comparable to the recess 54 in the entrance port body 46. In this instance, the recess 70 receives an exit orifice plate 72 having an exit orifice 74 therein. In order to establish a counter flow of air or gas with respect to the direction of feed of the metal product, the exit orifice 74 is made slightly smaller than the inlet orifice 58 whereby an effective flow of air or gas is created toward the inlet orifice 58. The assemblage is completed by means of a top cover plate 76 having a central aperture 78 therein in alignment with the central bore 60 of the air or gas distributor body 52 and maintained in intimate contact with the upper surface of the air or gas distributor body 52 with the aid of bolts 80 (FIG. 2).
FIG. 4 illustrates the use of an alternate entrance orifice plate 56a having a rectangular orifice 58a therein such as will suffice for feeding flat wire or foil or sheet products therethrough. A comparable substitution is made for the exit orifice plate 72 and an exit orifice 74 which will also conform substantially to the cross-sectional area of the metal strip product being fed therethrough. In this manner, an economical utilization of air or gas is achieved in that there is very little leakage through the wiper apparatus.
The apertures 44 and 48 in bottom cover plate 42 and entrance port body 46 provide a suitable drainage means for the treating liquid removed from metal strip 12 whereby the treating liquid may drain back into bath 16. It is also possible to vary the distance of the wiper apparatus 10 from the surface of the treating bath 16 and thereby control the temperature of the treating liquid within the wiper apparatus. In some instances, the entrance port is in contact with the surface of the treating bath 16. In these instances, it is especially important to have the inlet orifice 58 larger than exit orifice 74. This construction allows more air or gas to pass through inlet orifice 58 and thereby prevents oxides or the accumulation or surface sludge from clogging the inlet orifice. When the entrance port is affixed at a distance of 2 or more inches away from the surface of the treating bath, the entrance and exit orifices may be the same size provided that the surface sludge or surface oxide from the bath is not being carried into the entrance port. In either case, the orifices should be rounded to prevent scoring of the metal strip passing through them.
When the apparatus 10 is used to wipe molten lead or lead-bismuth, mild steel entrance and exit orifice plates 56 and 72 have been employed. When wiping water or water-oil emulsions, polyvinyl chloride (PVC) entrance and exit inserts have been used. When wiping lead-bismuth at a temperature of less than 610° F. polytetrafluoroethylene (Teflon) entrance and exit inserts have been used. In all tests, the main body of the assembly enclosing the inserts, has been constructed of mild steel.
When wiping flat wire with a nominal dimension of 0.375 inches long and 0.025 inches wide, lead and lead-bismuth were wiped with entrance orifice dimensions of not greater than 0.380 inches long and 0.0342 inches wide. No visible signs of molten metal were left on the metal wiped thereby.
When wiping flat wire with the same nominal dimensions as before that is .375 inches long and .025 inches wide, water and water-oil emulsions were wiped with entrance orifice dimensions of 0.380 inches long and 0.0625 inches wide.
When wiping round wire of water and water-oil emulsions, the same entrance and exit inserts were used as with flat wire. A piece of masking tape was used to cover the exit orifice and the wire was used to punch a hole through it.
The exit orifices when wiping lead, lead-bismuth and water and water-oil emulsions from the flat wire were the same dimensions on each exit insert, respectively, 0.380 inches long and 0.0312 inches wide.
In all these test, the volume of air or gas consumed is very small because of the close tolerances between the sides of the orifices and the surfaces of the metal being wiped. Argon gas was used to wipe metal from aluminum to prevent further oxidation thereof at a maximum flow of 15 cubic feet per hour at a line pressure of 25 psig with flat wire speeds of up to 600 feet per minute. Had it not been for responding difficulties, it is believed that higher speeds could be used with flat wire. In wiping water and water-oil emulsions from flat wire at 600 feet per minute, air at a line pressure of 25 psig was employed. The same pressure was used at wire speeds of up to 1,350 feet per minute for water and water-oil emulsions.
Since the wiper apparatus is relatively simple in its construction, it may be employed continuously without maintenance except for erosion caused by the gas or air employed. The apparatus can be used to wipe substances from round wire and rod in high speed molten metal annealing operations. The diameter employed in the air or gas distributor 52 is not critical as long as enough flow of air of gas passes through it and distributes itself evenly about the surface of the metal being wiped. The length of the distributor is determined by the same criteria.
While the recess 54 is illustrated and described to be contained within the top entrance port body 46, it could be placed alternatively in the bottom of gas distributor body 52. Also while recess 70 is illustrated and described to be contained within the top of gas distributor body 52, it could be placed alternatively in the bottom of top cover plate 76.
While presently preferred embodiments of the invention have been illustrated and described, it will be recognized that the invention may be otherwise variously embodied and practiced within the scope of the claims which follow.