US1994802A - Wire enameling - Google Patents

Description

Ma-gh Yi9, 1935. A, H; ADAMS '1,994,802

WIRE ENAMELING Filed June 3, 1931 5 Sheetsl-Sheet 1 .Tnc- BY WVQQ AT'TORNEY March 19, 1935. A, H" ADAMS l l 1,994,802

WIRE ENAMELING Filed June 5, 1951 s sheds-sheet 3 i Ffn ARINUR H. IADAMS INVENTOR BY@ -Lx @lv-AMJ, ATTORNEY Patented Mar. 19, 1935 This invention relates to new and useful improvements4 in wire coating, and more particularly to a novel process and apparatus for enameling, or coating with some other substance, wire 5 or any other object.

ll f.)

It is the object of the present invention to overcome the difiiculties experienced by uneven enameling or pick-up of the wire by delivering a positive measured volume of compound to each unit length of wire which it is desired to cover. The compound is delivered from an easily checked central supply and has no chance to evaporate or be contaminated, avoiding thus the difficulties encountered in maintaining the compound at a close specific gravity, viscosity and temperature.

In order more clearly to explain the invention and the manner in which it applies to the art of enameling, I shall iirst set forth in some detail vthe nature of the difficulties encountered in prior enameling processes and then point out the manner in which they may be obviated by the present invention.

It is becoming evident that in the wire enameling art the oven or baking means and process will shortly outstrip, or has already outstripped, the means o'i method of applying the coating of vwet varnish or compound to the wire. By this is meant that, were it not for the troubles introduced in evenly coating the wire with varnish or compound there are available means and methods of baking at a much higher wire velocity than is now practiced.

The practice has almost universally been to pass the wire through a. pot or receptacle of compound, or in some cases to pass it through devices where the compound is flowed onto the wire. In both types the Wire picks up by adhesion a quantity of compound per foot that depends upon its velocity, the condition of its surface and `the viscosity and surface energy of the compound. The higher the velocity of a given size of wire the more heavy the pick-up. The higher the viscosity of the compound the heavier the pickup. If the wire surface is not clean and dry and/or free from greasy or soapy film (often present as a result of the lubricants used in the* drawing of the wire) it may pick up less or no compound. The lower the surface energy the heavier the pick-up.

The viscosity of the compound, which vitally affects the pick-up,- varies not only due to slight differences in its manufacture and in the amount of solvent or thinner put in (relatively minor but real variations)4 bt also-due to the continuous loss of thinner by evaporation and, most uncon-V rents) vthe surface tension ultimately constricts trollable of all, due to daily and hourly temperature changes inthe enameling room; also variations in the temperature of the wire itself cause variations in the temperature of the compound it touches (stored in a warm room, freshly delivered from a cooler place, etc.).

Wire enameling plants have been equipped with accurate specific gravity control of the main compound supply by which thinner is added automatically as the specific gravity, constantly being measured is found to rise. One such device of the prior art eliminates the effect of ternperature on specic gravity by comparing the gravity of the compound with that of a definite mass of standard compound in thermal contact with it.- By this means, combined with a constant circulation of the compound, the variations in viscosity due to variable original percentage of thinner and/or evaporation, in the machine pots, of the thinner are'well controlled, and those due to temperature are somewhat minimized.

Enameling rooms have also been sealed and artificially ventilated and maintained at uniform temperaturesometimes as high as 110 F., with some discomfort to operators-with the object of reducing these viscosity variations.

All these methods have been improvements, but are expensive and troublesome, especially the maintenance of uniformly warm and draft-free room atmosphere, and have not practically quite eliminated allvariations in pick-up.

But if we assume that the pick-up can by the latest methods be made uniform there remain two serious restrictions on the speed of baking that are due to the dip method of coating. By speed is meant actual running velocity of the Wire. These are:

i, First, the relationship of surface tension to viscosity of compound in the early stages of baking; and 40 Second, the large amounts of thinner that have to be evaporated in the baking and which increase the time of the bake. This second re- 4striction, as will be explained, is a result of the first. 45

To explain the effect of the surface-tension viscosity relations of the compound on speed it is necessary to visualize the wire coated with compound as constituting a sort of thin stream or jet. The action of surface tension on a smooth small stream of Water or other liquid falling from a height'i's ,well known. Depending uponthe size, surface tension and viscosity of the stream (eliminating all effects of air resistance or cur- 5 ing necks. And further down the stream the surface tension constricts these necks to the vanishing point, breaking the stream into drops.

This, of course is due to the fact that the tension remains constant, and, therefore, the hydrostatic pressure inside the surface Where the stream is narrowed is greater than where it is enlarged, thus forcing the liquid entirely out of the necks and into the swollen places. Another example of this action is the greater thickness of varnish or paint on. a fiat or large radius surface than on a corner of small radius.

In the stream, consisting of a wire coated with compound, the same action tends to occur. It is opposed by the fact that the core of the stream is solid wire, and that the rst few layers of molecules are held by forces of adhesion acting perpendicularly to the surface of the wire, and the next layers, dueV to that yproperty we call viscosity or internal friction, require work done upon them toI shift them-along the wire. It is obvious that in a wire coated with wet compound, a struggle is enacted between surface tension on the one hand tending to form successive necks and bulges by displacing some of the layer of l compound lengthwise of the wire, and the forces of adhesion and the internal friction or viscosity tending to resist this displacement on the other hand.

These forces of adhesion, perpendicular to the Wire surface, plus the viscosity or internal friction of the compound, again opposed by surface tension and to a limited extent by gravity, again determine how thick will be the picked up coat on a given wire emerging vertically from a bath of compound at a given speed. The surface tension as it were squeezes out or extrudes the compound from between itself and the wire as cleanly as it can in the time it has. 'Ihis action occurs at the meniscus, or just abovethe horizontal surface of the compound. The moving of the molecules against the forces of adhesion and against their internal friction obviously constitutes work in the physical sense. The energy that does this comes in part from gravity but mainly from the constantly renewed surface tension as the surface perimeter of the meniscus shrinks.v

In other words, it is the surface energy of the compound, i. e., the rate at which it can do work, that mainly strips off against internal friction the excess compound fed to it by the energy of the rising wire acting through the forces of adhesion and internal friction. Thus we have a very sensitive balance between the surface energy and the energy delivered by the wire through the above forces.v

There is a point beyond which the surface tension is unable to go in extruding the compound under the meniscus.v It seems likely that the viscosity or force resisting slip of molecule on molecule is not an important factor if the motion of the wire is slow enough, and that surface tension will at slow speeds extrude practically al1 the molecules that are not bound to some extent by the force of adhesion. Such a coating could not, of course, be further distorted or necked by surface tension.

From the above discussion, it is obvious, as is in fact practically experienced in the art, that delivery of too much energy' (via adhesion plus viscosity) by the wire-i. e., too high speed-g-can easily overcome the surface energy of the compound and put on the wire a coating so thick that the further action of surface tension will be able to neck it. This results in what is called lumpy or beady wire.

There are other` interesting considerations, on which not enough work has been done, involving the relative changes in viscosity and surface tension as the Wire enters the baking zone. Some measurements made seem to indicate that while heat reduces surface tension and viscosity no great relative changes are to be found (in the compound tried) and that the probabilities are that conditions for forming necks or beads do not get much worse as the wire and coating are heated. 'Ihis may not be true of other compounds.

Now it will be observed that the thinner or less viscous the compound the more of it out beyond the adhering layer will be extruded at the meniscus at a given speed. On the other hand, insofar as any is picked up, beyond the.adhering layer, the more easily and quickly it will be necked or beaded by surface tension. On the whole, however, it would be expected, and is found in practice, that in a thin compound wire can be run yfaster without beading than in a thick one.

'I'here are decided limits to this. In the first place a thinner compound means a much thinner baked coating-the wet coating being itself less thick and the proportion of vaporizable solvent therein being at the same time greater. 'I'his requires more coating operations or passes to obtain thedesired final coating on the wire. In the next place, the greater proportion of solvent to be evaporated takes more heat energy to complete the baking (which is not Within reason so important though not at all negligible), and also takes more time to complete the baking. Thus as we speed up the wire by using a less viscous compound we'need to lengthen our oven or baking chamber much more than' in proportion to the increase of speed-or, what is the same thing, to increase the temperature of the baking. Temperatures may not be too high without ignition occurring. And finally, since wire enameling compounds are necessarily viscous, the thinnest practicable mixture will be picked up in beading coats at speeds barely above those in commercial use today.

To solve this problem, it has been imagined" and tried in a limited way to use thick or viscous mixtures and pass-the vwire through a wiper to remove the excess that causes beading, thus at one stroke reducing the amount of and time of baking heat required and getting higher wire speeds. Another probable gain in using coatings of compound without thinner lies in the fact that less'gas must be evolved and forced out through the coating. Microscopic examination shows that any wire enamel coat is full of minute craters where the gases have forced their way out through the compound as it begins to lose its fluidity.

The use of thick compound will, of course, give thicker coatings per pass, and for much wire in use today a single pass or two passes would be sufficient. In wire of present practice coated by many passes the inner coats have been through the oven a number of times, and are probably thereby somewhat more severely baked than 4is desirable forfiexibility.

Some success has been attained in the use of thick compound, dip applied and wiped olf but there remain the trouble of variable (thoughA not beady) coatings due to temperature and other changes in the compound and the wire, to the variations in wiping die diameter or wiper setting and to the variations in wire diameter, and as so far known the extremely serious objection that no method has been devised to prevent the wire where it enters the viscous compound from entraining air bubbles or churning. The compound supply around the wire becomes full.. in time, of an aerated, frothy, or emulsified compound and the Wire coating made therefrom -is useless for the purpose intended. It should be carefully noted that the more viscous the compound, and the more of it is subject at one time to this churning action of the entering wire the finer the air bubbles become, the more of them there are per cubic centimeter of compound and the less chance there is Vthat they may come to the surface of the wet coating on the wire and break t before they'Y are baked in. This last point is doubly so due to their smaller size and the greater resistance of the viscous compound. Air bubbles have always been a difficulty, even with viscosities ordinarily used.

The -present invention overcomes all the troubles of uneven pick-up and the need for close specific gravity, viscosity and temperature controls by a positive measured delivery per foot of wire of a predetermined volume of compound, which may come from an easily checked central supply and has no chance to evaporate or to be contaminated. This method by its nature obviously overcomes all the variations of coating just outlined as inherent still in the prior attempts to put on an excess of viscous compound and to wipe off that excess. It avoids the tendency to Ychurn or aerate the compound by reducing to almost nothing the volume of compound subject to this churning, and it greatly mitigates the tendency to include air bubbles in the coating by a number of methods: prewetting or priming of the wire, reduction of viscosity of the compound without solvent by heat applied to the small portion just about to flow onto the wire, in one alternative structure by an air seal formed of the prewetting or priming liquid, and by apply- Y no ing a fine hair or wire brush immediately above the pick-up point to release any air bubbles formed. This brush, of course, neither removes nor adds any compound once it is wet.

This invention avoids certain very serious increased labor costs inherent in some of the prior methods of applying thick compound and then removing the excess; notably much greater time needed to string them up and more frequent Stringing up because 'of their inability to pass without breakage kinks and knots in the'wire. Knots are often used to avoid restringing by joining the end of a new supply of wire'to the last of the old one.

Since many modern enameling ovens operate with controlled draft and require the lower or entrance end of the oven or baking tube or chamber to be sealed, in this invention advantage is taken of the desirability of prewetting the wire with thinner or very thin compound to use the supply of this material as a seal in any of the ways in which the coating compound is so used in present practice. Also one form of nozzle disclosed can itself form the seal.

Since ,it is the main purpose of this predeter' mined delivery rate of compound to run the wire faster with a thick mixture and without a beading pick-up, than can be done by a natural or ordinary dip pick-up, it follows that the wire in this invention at au times tends to take the compound, even though thinned by heating, at' `a faster rate than it comes.

If under these conditions the wire were passed adjacent to a plain free delivery orifice there would be a tendency for the Wire to pick up all the available compound, partially emptying for an instant the mouth of the orice, and then to run bare or merely smudged a brief distance, and to repeat this action. In other words, there is an inherent tendency for the pick-up from a measured compound delivery that is less than natural for the wire, speed and compound, to be irregular.

For this reason, one type of nozzle of this invention has a small delivery orifice or orifices adjacent the wire, reducing the amount of coinpound available to the wire at any instant to so small an amount that the above irregular pickupcannotl occur, or is so rapid as to be substantially uniform,

The important feature of this type of nozzle is that the natural depth of 4pick-up is allowed to'occur on a side of the wire. The wire being somewhat free to move closer to or farther from the orifice, will-when the compound is more viscous-pick up a thicker stripe and a narrower one. When the compound is more fluid a thinner and somewhat wider one will be taken.

The prewet surface of the wire tends both to make this pick-up more rapid and tocause the stripe to spread at once around the wire.

A slow spiral contact of the nozzle ute on an arc of the wires periphery above the delivery point insures the stripe however sluggish, being spread clear about the Wire. This form of nozzle also utilizes the lateral spring of the wire'itself to let the thickness of the coat adjust itself at all points. It is also very practical for quick threading of the wire.

Depending on the speed of wire and viscosity of compound, the final fine brush spreader shown above the nozzle-intended to further equalize the distribution around and along the wire and to break and remove air bubblesmay be used or omitted.

Another suitable form ofnozzle is a bushing or sleeve completely surrounding `the wire, fitting quite close at the bottom, with a relatively large central clearance chamber all around, and a top orifice preferably not as close as the bottom one but of such dimensions that the amount of compound that would be naturally drawn through it by the moving wire is a trifle less than the amount desired as a coating. Naturally, above, means assuming an ample but pressureless supply. The measured feed of the compound is into this nozzle through a hole in the side, and it fills the central clearance chamber. As the top orifice does not let the wire naturally draw through quite as much compound as is supplied by themeasured feed the level of compound rises in the supply tube until the'head or pressure just balances the resistance of the top or outlet orice. 'Ihe lower orifice cannot leak (and reduce the pressure in the` bushing and waste the compound) because of the drag of the upwardly moving wire.

This nozzle is theoretically and in manypractical ways the one preferred. It is not the most practical for all cases merelyon account of not passing kinks and knots, and also because it takes more time to thread the wires through these bushings when Stringing up.

One of the ways in which this bushing type is superior is in suppressing the formation of air bubbles when the' wire is prewet. As is shown there are wiping means just below the nozzle to l terially and thus it would take more time and/or heat to bake the coating. If, as shown, a suitable wiper washer of thin rubber or felt or thin tough leather or cork is attached to the entrance end of the bushing nozzle, with a hole in it fitting the wire closely, the thinner (or, better for this purpose, the thin compound will pile up against this washer and form a seal through which no air can be drawn at the highest attainable speeds.

In plants where the last end of the old supply and the beginning end of a new supply can be` butt welded or brazed together without leaving too large a' ash or swelling., the above bushing type nozzle is certainly best.

A split form of this bushing will somewhat overcome the knot trouble. A split design is also shown and would take very slightly more time in originally Stringing up the machine than the long spiral type or than present common machines. A desirable modication of this bushing type nozzle is to make the top orifice star shaped with the inward points on a circle almost touching the wire. These have the effect of disturbing the coating and letting air bubbles break out more readily if the limit of wire velocity and thickness of compound is practiced so that bubbles occasionally occur. v

The bushing type nozzle may, like the spiral type, be used with or without the spreader brush to break up air bubbles.

'I'he principles of the spiral type nozzle may be embodied in a number of quite different forms. These principles are: Y

1. Reduction of amount of immediately available compound at point of rst delivery to the Wire to a quantity so small that the irregularity of take-up above described cannot be noticeably large.

2. Application of compount at first not all around the wire but in stripes.

3. Freedom of the wire and the applying nozzle surface to move or adjust themselves relatively to allow the stripe or stripes picked up to approach their natural thickness.

4. Spreading surfaces above the point of iirst pick-up to assist the stripesto spread clear around the wire.

5. Freedom of the wire and of the applying and spreading surfaces to move apart sumciently to pass knots and kinks without breaking the wire.

Another good form of nozzle consists of a tuft of ne hairs orextremely ne wires, like a small round and pointed artistsrbrush, but having ahcllow core. The holder or attachment base of the hairs to be of a horseshoev or nearly closed ring shape, and the compound to be positively fed at the predetermined rate into the hairs near their roots. It .will be seen that all of the above ve principles are embodied inthis form,v al

though the stripes of principle 2 would be so many and so small and overlap each other so much that the compound would be substantially applied all around the wire.

Many other forms of nozzle such as one using two leaf springs formed to nearly enclose the wire and with angular or spiralembossings to spread the compound around the wire and with a fixed small orince nozzle leading between them or just below them to deliver a stripe or stripes onto the wire, can be devised to embody the principles of the spiral nozzle illustrated.

A common cut-off means to stop the now from all nozzles when the machine is stopped must be provided. This is shown as one long spigot type multiple valve. The stream from the secondary distributor nozzle must at the same time be stopped by either stopping the pump if directly connected, or by lay-passing to sump the stream from the proper pocket of the primary distributor if such is used.

An individual cut oif means to stop the now through those nozzles coating one wire (in its several passes) is necessary when one head or wire is shut down 'for any reason. 'I'he means shown is a valve in each feed or stand pipe to by-pass the flow from each pocket of the secondary distributor to sump and to shut off the standpipe below it. The compound will not run out of the small nozzle orifices to any extent when so shut oil, as air cannot enter to replace it.

The means and method for obtaining a measured rate of delivery of compound (by volume) to a machine or unit and thence to an individual wire coating point is novel. A definite stream is obtained by running a positive displacementy pump, preferably one of the rotary type, at an exact; speed. A synchronous motor with speed reducer, preferably of the iniinitely variable type, is shown. If this is used the speed of the wire driving parts of the enameling machines served must be kept quite constant, as by synchronous motors. Or the positive displacement pump drive may be mechanically instead of electrically related, as by gearing, to the drives of the enameling machine or machines it supplies. The denite stream from the pump is then time-divided by a revolving nozzle that causes it to ilow for a denite fraction of one of its revolutions into a receptacle or funnel or pocket occupying a certain arc of the circle swung by the stream.

In the drawings, Fig. 1 is a vertical cross-section of an enameling machine embodying various features of the invention;

Figs. 2 and 2a are a side elevation and horizontal cross-section, respectively, of one type of spiral nozzle;

. Fig. 3 is a side elevation and Fig. 3a a horizontal cross-section of another type of spiral nozzle;

Fig. -3b'isa horizontal cross section of the spiral nozzle, showing the arrangement oi the compound discharge orince;

Fig. 4 is a side elevation and Fig. 4"v a horizontal cross-sectionof a nozzle holder;

Fig. 5 is a vertical and Fig. 5 a horizontal crosssection of the brush spreader;

Fig. 6 is a vertical cross-section of a brush type nozzle;

Figs. 7 and 8 are vertical cross sections of two bushing type nozzles;

Fig. 8e is a horizontal cross-section of. Fig. 8.

Figs. 9 and 9n are horizontal and vertical crosssections of holders for nozzles like the ones shown in Figs. 'I and 8;

Fig. 10 is a top plan view of a holder for a modined nozzle like the one in Fig. 8;

Fig. 11 schematically illustrates the compound distributing system; y

Figs. 12 and 12 are a vertical cross section and top plan view, respectively, of the primary distributing-funnels; and

Fig. 13 is a perspective of the wiper.

It willbe obvious to those skilled in the 'art that the invention is not limited to the specific embodiment herein disclosed, nor is its application restricted to the enameling of Wire.

The manner in which my invention can be applied to a well-known type of baking oven is schematically illustrated in Fig. 1. As shown in this figure, the Wire 1 is drawn from a supply over a driving pulley 2 and an idler 3. A portion of the wire is surrounded by an oven or baking tube 4 consisting of electric heating units 5 supported within a cylinder 6 of insulating material. The air control in the oven is eected by means of a damper '7 provided within a port 8A of the insulating cylinder 6. It will be understood that the general arrangement and details of the machine, other than the measured feeding of the compound and the method and apparatus necessary for accomplishing this, form no part of this invention. The oven design, the type of heat, whether gas, electric, wholly or partly recuperative of the B. t. u. in the solvent and vapors, radiant or convective or mixed, the draft and temperature conrols, etc., are none of them part of this invention. Nor are the supply and tension, take-up or spooling, or driving arrangements of the wire.

The compound is applied to the Wire through a nozzle located at 8, after the latter has passed. through a bath of thinner or priming compound 9, contained in a trough 10 within which the idler pulley 3 is located. The section of the wire between the priming bath and the oven is enclosed in a chamber formed by an extension 1l of the insulating tube 6, to which access may be had from the outside through a sliding or swinging door 12.

In accordance with the present invention a seal 13 for oven drafts is used. This seal may be of another type such as the one shown in Patent No. 1,787,416 to F. Martindell in which the cheeks of the lower pulley 3 nt closely between the end walls of the pot or trough 10 and the ridge or rib 3 comes down in serrations, fitting very closely but not touching the grooved periphery of the pulley 3. In such structure the level of the priming compound 9 need only be as at 14, high enough to cover thevery bottom vof the pulley. 'I'his seal is maintained by the lm of compound coating all surfaces of the pulley.

At a point above the nozzle 8, where the wire enters the heating tube, the latteris ypreferably f narrowed, as indicated at 15. The desirability of this arrangement depends upon the heat used in the oven .or tube and in the danger of too much heat being conducted, convected, or radiated'down upon the nozzle and associated devices.

One embodiment of the nozzle is shown in Figs. 2 and 2a. It consists of a bushing 20 having a slow spiral flute 21 cut therein. The bushing 20 is long enough to take in 270 of the lead of the spiral flute if, as shown, the flute is about a 90 ilute (see Fig. 2a). .The amount of twist in the bushing 20 plus the angle of the wire covered by it at any point must be at least 360, e. g., a 90 flute and a 270 lead, If the flute were 60, it would cover at one level V120" of the wire periphery and the amount of twist needed in the bushing would be only 240. The compound is introduced through orifices 22 in the lower part of bushing 21. The stripe of compound deposited on the wire through the orices is spread clear about the wire as it moves through the flute 21. The lateral spring of the wire itself allows the thickness of the coat to adjust itself at all points within the flute. A further advanage of this type of flute is that it lends itself to quick threading of the wire when the machine is started.

A moaned form. of this nnte is shown in Figs. e

and 3a. In this modication the bushing 23, provided with compound discharge orices 24 (three lbeing shown in the drawings), is milled from a solid rod or may be made by twisting a flatwire in avery small spiral. The correct lcontact on the wire is at a point only (see Fig. 3a) therefore the spiral or amount of lead taken in by the bushing should be 360.

The mounting structure for the nozzles illustrated in Figs. 2 and 3 is shown in Figs. 4 and 4B. It consists of a bracket 25 with a socket 26 which may be a tight fit for the foot of the nozzles 22 or 23, so that it is merely pressed or tapped in or, as shown in Fig. 4a, a set screw 27 may be used to hold the nozzle in place. The duct 28 leading to the 'orices 24 leads through the bracket 25.

In order more completely to equalize the distribution of compound around `and along the wire and to break and removeair bubbles from the coating, a nal ne wire brush spreader 30 (Fig. may be mounted on the holder 25 by means of a bracket 31 to engage the wire above the bushing or nozzle 20 or 23. As shown in 52, the brush spreader 30 is in the form of a horseshoe, so that the wire 1 may be readily inserted. A similar horseshoe-shaped brush 32 is shown in Fig. 6 in which compound feed ports 33 are provided in the frame 34 all around at the roots or" the ne wires or bristles 32. Such brush may therefore be utilized as a combination feed nozzle and spreader. v

Still another form of suitable nozzle is illustrated in Fig. 7. It consists of a bushing or sleeve 40 completely surrounding the wire l. The clearance 41 between the bottom of bushing 40 and the wire 1 is just sufficient for free passage of a wire of maximum diameter. It should not be of any appreciable length. The central clearance 42 between sleeve 40 and the wire l is relatively large, and the top clearance 43 is calculatedby the laws of flow of viscous fluid films between moving surfaces from the wire diameter and the .desired thickness of wet coat, so that it is from to 30% smaller than it would be to pass the desired coating without any head in the space 42 and the port 44 through which the compound is introduced. Thus when the wire does not accept the measured quantity of compound, the head in the standpipe 17 will rise until it does. The clearance 43 may never 'be greater than will pass by natural flow with no head the desired quantity, because in that case, an irregular application (interrupted application) of enamel will occur at point 45 where the wire l emerges from the sleeve 40. If the clearance 43v could be exactly that through which the wire would draw the exact desired quantity at all times, then no head would be required in chamber 42. If this condition be fulfilled for, say, #40 wire, of minimum diameter (wire of one size varies as much as (i1/2% total in the iiner'sizes, e. g., #40 or finer), the clearance will be reduced by 00008" when the Wire happens to vary to the maximum. And this .00003" variation may mean as much as or even of clearance area at 43 if a thin coating is maintained. Incidentally, it is thus clear why the measured feed method 'is superior to the prior die-wiping method. It should be stated that the larger the wire the less the variation will be in relation to the diameter, but not in relation to the ordinary thickness of coating. The variation in clearance 43 and hence in coating, if no head is used, owing solely to the diameter variations of the larger wires, may run above 30%.

The constricted part 43 of the bushing 40 is made short to reduce the resistance of the compound when being forced at greater'than natural rate through the orifices.

The chamber 42 is carried down nearly to wiping washers 46 which are held within the lower part of the sleeve by means of a hexagonal nut 47A. The chamber 42 is constricted to the clearance 41 to support these washers right up to the wire. The washers 46 are of lofty or resilient line lambs wool felt or the like, and on top of each'washer 46 are washers 47 which are of the oil resistant type of cellophane or thin, soft rubber or other resilient; material impervious to and not attacked by the compound. The purpose of washers 47 is to reduce seepage of compound or thinner through the porous felt washer 46. The washers 46 and 47 will remove most of the thinner or priming material from the wire emerging from the trough 10, and this priming, together with the washer, will form an airtight seal for :the chamber 42 so as to prevent the formation of air bubbles and any other change in the characterlstics of the compound applied through duct 44.

Since the chamber 42 is brought down close to the washers 46 and 47, the head in the chamber helps resist the drag of the wire for the very much less viscous priming or prewetting material 9. By a proper choice of viscosity, a practical balance of hydrostatic pressure on both sides of the seal washers is possible of attainment.

The measured feed of the compound through orice 44 lls the central clearance Achamber 42. As the top orifice does not let the wire naturally (i. e., assuming an ample but pressureless supply) draw through quite as much compo-und asis supplied by the measured feed, the level of the compound rises in the supply tube' 17 until the head or pressure just balances the resistance of the outlet orifice 43. The lower orifice 41 cannot leak and reduce the pressure in chamber 42 and waste the compound because of the drag of the upward moving wire.

A modied form of the bushing type of nozzle is shown in Figs. 8 and 82. Here the wire is surrounded by a sleeve or bushing 50' having a large central clearance chamber 51 and entrance and exit clearance openings 52 and 53 corresponding to 4l and 43 in Fig. 7. The washers 46 and 47 function in the same manner as in the previous ligure. The difference between the two types of nozzles is that the compound introduced through the orifice 53 is applied to the wire 1 in stripes or ridges around the periphery, owing to the fact that it is led to a star-shaped orifice 55 encircling the wire. The area of the starpoint openings 55 plus the clearance 56' (Fig. 8H) between the wire 1 and the walls of sleeve 50' could be calculated from the laws of viscous ilow, but an experimental determination would be best. The object is to make this area such that with minimum diameter wire and compound supplied to the bushing underno head, the quantity drawn through the opening by the moving wire shall be as nearly as possible equal to but not more than the desired quantity. Then the automatic changes of head will take care of normal or maximum wire.

O1' course, the bushings shown in Figs. 7 and 8 may be used in combination with the brush type spreader shown in Fig. 5.

The holder for the solid bushing nozzles may be substantially like the holder shown in Figs. 4 and 4 for the spiral nozzles. It need not be openy in front and may consist of a battery of nozzlea As shown-in Figs. 9 and 9B, a holder body 60 is;

provided with openings within which the nozzles.'

vfor instance, fty, are held in place by means of screws 61. The ducts 28 to the bushing orifices lead through the holder 50. As shown in Fig. 9a, back of the holder 60 a heating element 62 is provided which may be of the usualv electric strip heater type, but a gas ame or hot oil circulation or conduction from the oven above may be used.

In Fig. 1 the pipe connection 28 leading from standpipe 17 and cutoif valve 16- to nozzle 8 is shown passing around and in contact with the lower part of metallc oven tube 6'L by which it is warmed. The bushing holder body 60 should be covered with thermal insulation 63 for economy. The heat developed within the holder is to enable a thicker, i. e., more viscous, compound to be fed on smoothly and with less drag on the wire. Heat for this purpose is still more necessary in the nozzle holder 25 (Figs. 4 and 4*) for the spiral type of nozzle, because the greater the reduction in viscosity, the less the tendency to drawing in air bubbles by the speed of the wire. While the holder 25 is shown as an individual holder, it could be formed of a strip of material like 60 with sockets open in front, however; i'ngeneral, like that shown in Figs. 9 and 9.

In order to minimize the diiliculties encountered with the solid bushing type of nozzle shown, for

example, in Fig. 8, these nozzles and their holdy ers may be modiied in the manner shown in Fig. 10. Here the nozzles are split into two halves 70 and 71. The halves 70A are carried in a block or mounting plate 72 and the halves 71 in a block 73, which is movable with respect to block 72 on guide pins 74 by means of a pivoted handle 75 which is mounted on the frame 76 of the machine by means of a pivoted toggle joint 77. In this manner any number of nozzles serving for the successive coatings of compound on one particular wire may be opened to permit a knot to pass through. Knots are often used to fasten the wire to a new supply that is being dragged through by the last end of an old supply. With such split nozzles the washers 46 and 47 are heldagainst the bottom of the bushing by means of screws 55 and clamp 56 (Fig. 8) instead oi.' the threaded gland nut 47 (Fig. 7), because the latter cannot be split so easily. Preferably, the split between the two halves of the nozzle is angular to insure good registration of the two parts of the bushing and also to insure the wire being centered. The bushings are rectangular on the outside and maybe let in flush with their holders. When fully closed they and their Aholders may thus form a bottom seal to the oven above.

A common cut-E means to stop the ow from all nozzles when the machine is stopped is provided in the form of one long spigot type valve' 16. The stream from the secondary distributor nozzle (to be presently described) must, at the same time, be stopped by either stopping the pump directly connected, or by by-passing to mm'p the stream from the proper pocket of the primary distributor if such is used. An 'individual cut-oil' valve to stop the flow through those nozzles coating one wire in its several passes is necessary when one head of wire is shut down for any reason. The means shown is a valve in each feed or standpipe to by-pass the ilow from each pocket of the secondary distributor to sump and to shut of! the standpipe below. I'he compound will not run out of the small nozzle orice to any extent when so shut off, as air cannot enter to replace it.

The method and means for obtaining a measured rate of delivery of compound (by volume) through a. variable speed transmission or Achangei gear box 106. vIf suchanarrangementis used,

then the speed of thewire driving parts of the enameling machines must be kept quite constant,

as by synchronous motors. However, it will beobvious to those skilledin the art, that any other positive displacement 111.111,11)Y drivev may be used which, for instance, maybe mechanically instead 'of electrically related, as by gearing, to the drives of the machine or machines it supplies. The deiinite stream of compound from the pump is deliv` ered through a conduit 7 to a nozzle 108 associated with the main or primary distributor. A motor 109 constantly rotates thel nozzle 108 turmigh a chain drive 11o to divide'the stream between machines or groups of machines, i. e., between secondary distributors. During each revolution of the nozzle 108 a denite fraction ofthe compound will ow into a receptacle or funnel 111 occupying a certain arc of the circle swung by the stream. As the nozzle 108 leaves the first receptacle 111, it discharges into the adjacent receptacle and so on. If there are sixty receptacles lll alike so that each occupies 6 of the circle, the amount of compound delivered by the stream in one revolution of the nozzle 108 will be exactly divided between the sixty receptacles 111. This remains true whatever the'velocity of the nozzle revolution, provided only that this velocity does not vary suddenly. Obviously, the arcs occupied by successive receptacles or funnels 111 need not be the same. One may occupy 6 and an adjacent one may occupy 12. In that case the second would .receive just twice as much compound per revolution as the former. An arrangement of eight receptacles 111 in a circle is villustrated in Fig. 1l. From each receptacle 111 the compound may be fed direct to an enameling machine noz-V zle or through a conduit 112 to a rotating 'nozzle '113 driven like nozzle 108 and feeding secondary distributing funnels 114. This divides the ow from one of the main distributing receptacles 111 to the coating nozzles of an enameling machine.

In a large department with many machines, enameling wire from say #40 gauge to #10 gauge,

extremely different amounts of enamel will be taken by diierent machines. This might all be calculated and added up and the speed setting of one rotary pump 104 made to` give just that amount. There` might be one secondary distributor per machine and in the main or primary distributor one receptacle per machine. This would require rather large diiierences in the angle intercepted by one receptacle and another. Tying the whole large department to one measuring' pump is objectionable, because any shutdowns or machines or starting up of other machines requires a by-pass to a sump or a return to the main supply from the primary distributor receptacle lllfeeding those machines shut down.V Such bypass or' return flow may be eiected under the control of a valve 115 through a conduit 116 'which leads back totank 100'and which may be du'itl12 may .be caused to discharge from its associated receptacle 1,11 'to sumpfthroughcon# duit 118 u nder the controlof valve 119".Y However,

:this involves considerable. useless circulationfof4 compound for all'the idlemachines' in". the department. To minimize this it is advisable to break the, department into groups .and have a measuring 'pump 1ike104, each for` several groups of large machines, or even oneper machineiin be omitted), one each foranumber ofgroups of medium machines', 'one each for a'number of.

groups of small, and' one each for extra ne machines. It may even be convenient to have a pump per machine and to shutI it down with the machine. However, the 4size of the ldepartment and the nature of the business will determine the best arrangement.

The secondary distributor vcan divide the corn-lV pound required for any one machine or if a .unit or number of machines can always be run on the same size of Wire, it may divide the requirementsof such a unit between the individual'passes or wire coating points. If the wires are coated only once, then all the divisions are alike. Ii, however, the wires receive two coats or more, then my invention permits the use of different amounts oi compound for the first and second successive coats.

In 'the older practice of enameling, a wire hav'- ing received' one coat was larger and its second coat, by that fact, not only took more enamel, but wasalso slightly thicker. This is for the same reason that varnish lies thicker on a large radius than on a small one. In my system, by using two or more secondary distributors, each pass or coating ,can have a predetermined thickness. Thus enameled wire forsome purposesmay be best with one or two thin, and therefore harder baked and more adherent, inner coats, ,and with a thicker and somewhat more exible outer coat.

which case the main or primary distributor may For other purposes, e. g., tinned wire to be used in cable and requiring Ato be easily skinned, the exact reverse probably is true. This invention opens the way, therefore, for development and improvements in the enameled wire itself along the lines oi varying the depth and hardness of successive coatings. By means of my method partially polymerized compound may be applied to the wire, or two or more different compounds may be applied successively in two or more passes to one wire. y

Another way to attain this result without using two or more" secondary distributors (supposing, for instance, a machine or unit served by one secondary distributor handles 25 wires with three coats each, and if the ratio of coatings is once determined), is to subdivide the Z5 `pockets of this distributor unevenly.V For instance, the 25 pockets feeding the rst coating points or nozzles mayoccupy, s'ay `180 of the distributor; the 25 for the second coats may occupy 110, and the 25 for the third coats may occupy the remaining In the main distributor, dividing the main stream between a relatively few machines or units, each of whichv takes a roughly predetermined range of compound iiow, it is possible to use (as shown in Figs. lland 12) angularly adjustable interceptors 120 covering the flxed partitions 121 between pockets 111, and thus to vary las may be needed the quantity of compound de- 8 mageos are many, to vary a large consecutive group (forvpossible to provide interchangeable crowns of pockets or funnel's divided as desired (for instance, pockets in 180, 25 in 110 and 25 in '70 o1' the above example), with short pipe outlets so arranged as to be evenly distributed about the circle and to interpose these crowns between the rotating nozzle and a circle of evenly spaced pockets leading to the feedpipes. This is possible on the secondary distributors and not 'on the primary, because on the former the amount delivered per rotation per unit is small and the level or head will not be so suddenly varied thereby in a small diameter pipe as on the primaries. In the secondaries the level must not come up into the pockets which serve merely'as funnels 'but must remain at low levels in the pipes. In the primaries it must stand in the pockets. Moreover,l there are reasons why, on the secondary, the head must vary reasonably sensitively and rapidly. These reasonsv relate to the restriction at the feeding nozzle. In both general types of nozzle disclosed (the bushing or pressure type and the spiral or stripe and'spreader type), with their various possible forms; the

.compound does not iiow onto the wire at the measured rate unless an adequate and self-regulating pressure is supplied to compensate for variations in viscosity of compound, orifice diameter variations, etc. Instead of a standpipe or hydraulic accumulator, a pneumatic or other type might be used.

In starting an empty machine or after changing nozzles, it is desirable that this head for just balancing the nozzle Iresistance be attained as quickly as possible. Otherwise a certain amount of wire will ,be undercoated or overcoated. This waste of wire will naturally be minimized by knowledge of the approximate head that is needed for any'par7 ticular wire size or nozzle size. To facilitate this, the feedlines such as 122, are made of glass for a considerable portion of their height and graduated as indicated at 123. Feed line 122 forms a part-of standpipe 17 (Fig. 1).. 'I'his enables the operator to start a new size of wire on a machine with approximately the head needed for that wire size and coating thickness. He does this by rotating the distributor nozzle 113 a briefV time before he opens the nozzles at 16 and starts the machine, thus prefilling each line 122 to an experimentally determined mark' for that size of wire and thickness of coat. He can do this by a suitable switch controlling the measuring pump 104 and the motor of the secondary distributor. If the system uses both primary and secondary distributors, the primary distributor will be running and its. pocket 111 leading to his machine will be feeding to sump or back to the main tank 100. He will, in this case, first start the motor actual viscosity of the compound at two nozzlesv will be different, owing to slight temperature differences, the head needed to balance the nozzle resistance and feed the exact' predetermined the less constricted pockets and this explains why the removable crown of pockets may be used on the secondaries and not at the primaries.

The only danger of irregularity of final distribution of compound lies in the possible variation .in rate of iiovv through the secondary rotary nozzle. If the primary or main rotary nozzle 108 revolves slowly, it may on each revolution lincrease the head for an instant in the receptacle 111 leading to the secondary nozzle 113. Therefore, the main nozzle 108 should revolve quite rapidly to keep this variation in head negligible by adding a little compound often instead of more compound less frequently.` Throttles such as 119 in the pipes from the main receptacle 111 to the secondary nozzle 113, should be adjusted to keep `the level in the main receptacle 1,11 from either falling below level A or rising above level B. Since the height A to B may be as great as desired, this is quite easy. The reason is that each separate quantity added by the main rotary nozzle 108 to a main receptacle 111 will briefly change the level or head in the latter, but only insensibly as long as `the level is somewhere in the larger part of the receptacle. But if the level sinks to the restricted portion below A, or into the pipe 112, then the4 front of the machine, e. g., by chain or rod or other remote control means, and of course the glass standpipes 122 should be readily seen xand easily associated -each with its nozzle. These standpipes are best mounted on the front -face oi' oven 6, as shown in Fig. v1. 'I'he operation of valve 119 must also be easy. By a siphon or dip in the pipe 112 it may be brought from above the secondary distributor to a convenient place, or it may be remotely operated mechanically, electrically or pneumatically. It the measuring pump 104 feeds the secondary distributor directly, then its switch must be in a convenient location to the operator. 'I'he front face, of the oven would be such location. v

' The sliding holders for the-split bushing type of nozzle shown in Fig. 10 would, if used, be just inside the nozzle door 12 and the working handle 75 of each toggle would be accessible without opening that door.

The standpipes vl'l. 122 may all lead through a common shut-oil' valve 16 at the end of the machine and thence by small pipes to the nozzle holder and nozzles. The holder and nozzles are shown attached to the back wall of the wire space. They may equally well be attached to the front wall and the nozzle holder bar may itself contain the common shut-olf valve.

A wiper to remove as much as possible of the prewetting or priming compound or thinner may be used just below the nozzle, if the stripe or spreader nozzle type'is used instead of the bushunie of enamel per unit wire length containing ing type. Such wiper-is shown at 18'and more in detail in Fig. 13. Any form `'of wiper heretofore used is good. The one illustrated consists of a very long spiral or pigtail of fine spring wire 19 covered with a piece of rcotton sleeving. It is so mounted that the drag of the Wire 1 tends to shorten and open it, thus it cannot grab and break the wire. The end of the wire 19 should carry a tiny knob 19a or be bent back so that it Will not perforate the sleeving, and the latter is knotted or tied at 182L so that it will not slide on over the knob.

What is claimed is:

1. The method of enameling wire with a compound which comprises moving the wire and depositing thereon a coating of compound which is metered out and then pressure applied to the wire and which is independent of the velocity of the wire and viscosity of the compound.

2. 'I'he method of enameling wire which comprises moving the wire at a constant rate of speed, prewetting the wire, removing from the wire surplus wetting solution, applying to the wetted wire compound ata` predetermined rate,

Vand finally in baking the coated wire.

3. The method of enameling wire which comprises moving the wire at a constant rate of speed, prewetting the wire, removing from the.

wire surplus wetting solution, applying to the wetted wire a stripe of compound of a predetermined quantity per yard of Wire, wiping the stripe around the wire, and finally in baking the coated wire. y

4. The method of enameling wire which comprises forming a plurality'of substantially parallel stripes o f compound on the moving wire having a predetermined volume per foot of wire, and wiping the stripes all around the wire.

5. The wire enameling process comprising the following operations: supplying a predetermined quantity of compound from a common source of supply to a plurality of distributing channels in succession, and delivering from each distributing channel a predetermined quantity of compound per unit of wire length to an enameling position.

6. The wire enameling process comprising the following operations: supplying a predetermined quantity of compound from a common source of supplyA to a plurality Ofprimary4 distributing channels in succession, delivering from each primary distributing channel a predetermined quantity of compound per unit of Wire length to a plurality of secondary distributing channels in succession, and supplying compound from each secondary distributing channel to an enameling position.

. receptacles corresponding one to one to the use i points.

8. The method of accelerating the baking of an enamel on wire comprising `moving the wire at a relatively uniform speed, applying to the wire a compound of relatively high'viscosity accurately metered in a smaller quantity per unit wire length than would naturally adhere were the wire passed therethrough at that speed, and distribut ing this quantity uniformly.

9. The method of reducing the heat energy needed to bake on a wire an enamel coating of predetermined nal thickness, comprising positively metering onto the wire an appropriate volrelatively little volatile matter, in evenly spreading this about the wire, and in baking it.

10. The method of preparing ya baked enamel coating of desired thickness ona Wire, comprising the preparation of an enameling fluid containing a relatively low percentage of volatiles and having a relatively high viscosity, comprising the positive metered application of an appropriate volume of this fluid per unit length of wire, and the relatively brief heating of the wire and its coating.

11. The process of enameling wire comprising first wetting a wire in a fluid of relatively low viscosity, and second, of wiping ofi?, the bulk of 'the wetting fluid. so that an enameling fluid of relatively higher viscosity ,will more rapidly spread on the wire surface, third, of applying per unit length of wire a metered quantity of the enameling fluid before the remaining film of wetting uid is dry, and fourth, of heating the wire to harden the enameling fluid. l

, 12. .'I'he method of building an enameled coating on a wire comprising positively metering onto lthe wire a first coat of enamel of predetermined composition and. of controllable volume per wire length and then baking, and then positively metering onto the wire another coat of predetermined composition and of independently controllable volume per wire length and finally baking again.

13s The method ofbuilding on a wire an easily removable enamel coating of hard exterior comprising positively and independently and successivelyvmetering onto the wire a predetermined first coating of compound of relatively slow'baking characteristic, then baking it relatively soft,

' then positively and independently metering onto the Wire at least one other predetermined coating of compound of a quicker baking characteristic, and baking it relatively hard.

14. -The method of applying an air-free coating of viscous enamel to a moving Wire comprising, first surrounding the wire with a relatively thin uid miscible with the enamel, second, stripping off as cleanly as possible all of said fluid, and third, passing the still wet wire directly into the viscous enamel.

15. The method of applying an air-free coating of viscous compound to a moving wire that comprises passing the wire through a plurality of contiguous and misciblecompound masses of increasing viscosity, without exposure to air, and of stripping off all but a film of an earlier and less viscous compound at the point where a compound mass of higher viscosity is entered.

16. In a fluid distributing system, a source of fluid supply, a power driven mechanism at a plurality of points at which an exactly metered fluid `supply is required, a power driven stream control having its speed related to the speed of the power ldriven mechanism and delivering a steady metered stream, -.an interceptor for each of said points,- a cyclic distributor tune-dividing. the stream from said stream control between said interceptors, and an integrating andv compensating storage chamber between each of said interceptors and the corresponding one' of said points.

17. In a wire enamelingsystem, a compound reservoir, a plurality of enameling machines, means for delivering a predetermined quantity of compound fromsaid reservoir to each machine within a predetermined period, means for moving the wire'through said machines, 'and means for applying to the wire compound at said machines.

18. In a system o! the character described, a compound reservoir, a plurality of compartments, a spout adapted to discharge compound into said compartments, means for relatively moving said spout and compartments at a predetermined rate, a pump for delivering' a predetermined quantity of compound from said reservoir to said spout within a predetermined period, a plurality o! enameling machines, and a connection between each machine and a compartment.

19. In a system of the character described,- a compound reservoir, a plurality of compartments, a spout adapted to discharge compound into said compartments, automatic means for delivering a predetermined quantity of compound from said reservoir to said spout within a predetermined period, V`means operable at will for varying the quantity of compound delivery of, said spout to any compartment, a plurality of enameling machines, and a connection between each machine and a compartment.

20. In a system of the character described, a compound reservoir, a plurality of compartments arranged in a circlefa spout centrally mounted above said compartments, means for rotating said spout, a measuring pump for delivering a predetermined quantity of compound from said reservoir to said spout within a predetermined period, a plurality of enameling machines, a. connection between each machine and a compartment, said connections having transparent sections, and valves in said connections.

21. In a system of the character described, a compound reservoir, a primary and a plurality of secondary distributing systems each comprising a plurality of compartments, a compound delivery spout for the compartments of each system, and means for moving with respect to 'one another said spouts and the associated compartments, a pump for delivering a predetermined quantity of compound from said reservoir to the primary distributing spout within a predetermined period, a connection from each primary compartment to a secondary distributing spout, a plurality of enameling machines, and a connection between each machine and a secondarycompartment. i

22. In a system of the character described, a compound reservoir, a primary and a plurality of secondary distributing systems each comprising a plurality of compartments arranged in a circle, and a spout centrally mounted above said com- I partments, means for rotating said spouts, a

measuring pump for delivering a predetermined quantity of compound from said reservoir to the primary distributing spout within a predetermined period, a connection from each primary compartment to a secondary distributing spout, a plurality of enameling machines, a connection between each machine and a secondary compartment, said last mentioned connections having transparent sections, and valves in all lsaid connections.

23. In a wire enameling system, a supply of compound, means toapply to the wire a definite quantity of enamel for each unit length, being a less quantity than would adhere naturally to the wire, and means to distribute this quantity around the wire.Y

24. In a wire enameling system, a supply of compound, means positively to meter to the wire and means to thereafter apply'uniiormly onto the wire a quantity of compound less than would adhere naturally. p I

25. In a kwire enameling system, a supply of enameling compound, means to move the wire atY a certain speed, a wire enameling oven through which the wire passes, means comprising a pump of positive output to apply positively to the wire before it enters said` oven a denite quantity of compound for each unit length of wire this quantity being less than the natural pick-up.

26. In a wire enameling system, a supply of enamel, means for moving the wire, positive metering means to supply to the moving wire relatively thick enamel at a limited rate, means to relate the speed of the wire and the volumetric rate of the supply, and a baking chamber for the enameled wire.

27.#In a wire enameling system, a supply of enamel, a supply of wire, means for moving the wire through a plurality of passes, means to meter enamel to individual wire4 passes comprising: a common measuring pump, a revolving nozzle i'ed by said pump, a ring of interceptors receiving successively the flow from said nozzle, devices to apply enamel to individual wire passes below said interceptors, and storage tubes leading from said interceptors to said devices-to apply.

28. In a wire enameling system, a 'supply' of compound, means to move a plurality of wires, a compound flow control means related in speed to said means to move and delivering a predeterminable quantity of compound per unit length of each wire moved by said means to move, an application means to deliver the compound on the wire, and a compensator chamber to vary the pressure of compound at the application means t0 maintain an average flow through said application means equal to the delivery by said ilow con` trol means.

29. In a wire enameling system, a supply vof venameling fluid, means to move a'plurality of wires, a metering means related in speed to said means to move and delivering a steady stream oi' enameling iluid in proportion to its speed, a plurality of receptacles, a rotary cyclic distributor time-dividing the stream from said metering means between said receptacles in predeterminable proportions, application devices for applying enameling iluid to the wires and oieringvariable resistance to the uid ilow, and stand pipes between said receptacles and said vapplication devices in which the head or depth of fluid varies to compensate the variable resistance of said application devices.

30. In a wire enameling system, a source of enameling iiuid, a power driven enameling machine, a metering pump connected with the reservoir and related in speed to `said machine to deliver a metered stream of iluid, a cyclic distributor comprising a number of mouths each to receive the stream for its predetermined proportion of the cycle of the distributor, and means to vary the relative proportion of the cycle occupied by one of these mouths.

31. In a wire enameling system, a source of compound, a power driven enameling machine, a compoundy metering means related in speed to said machine and delivering a predeterminable stream of compound, a revolving nozzle carrying the stream, a number ot substantially contiguous mouths separated by partitions, and movable stream divide members located over said partitions 32. In a wire enameling system, means for moving the wire, a supply of enameling iluid, a power driven wire enameling machine comprising an oven and having means to pass a wire two or more times'through said oven, a metering means related in speed to said machine lfor supplying enameling iiuid in predetermined volume per unit length of a wire before its first passage" through said oven and for supplying enameling fluid in a different predetermined volume per unit compound, two means tocoat a wire, means toJ length before another passage through said oven. 33. In a wire enameling system, a source of bake the wirev twice, and two independently 'adjustable metering means to supply compound to said two means to coat, and common driving means for said two metering means.

3 4. In a wire enameling system, a supply. of enamel, wire moving means, means to :meter` enamel at a rate related to the speed of the wirev 35. In a wire enameling system, va supply of enamel, means to move wires, meansto meter enamel to the moving wire related to the speed of said means-to move, a stripe applier, a helical spreader permitting the wire to be forced against its own tension away from the stripe applier and from the spreader itself by the forces of viscous flow and adhesion. l

' 36. In a wire enameling system, a supplyI of enamel, means to move wires, means positively to meter enamel to a moving 4wire at a rate in a definite predeterminedly Icontrollable relation to the speed of the wire, and means to force the metered fiow of enamel to cover the Vwires periphery.

37. In a wire enameling system, a supply of enamel, means to move wires, means to meter enamel to a moving wire at a rate in a controllable relation to the speed of the wire, said last mentioned means comprising a chamber into which the enamel is fed surrounding the moving wire and having an entrance orice for the wire and an exit orifice for the wire, the former orifice being suiiiciently close tting to prevent the enamel from emerging at all against the inward motion of the wire and the latter orice being suiciently close fitting vto prevent the enamel from emerging with the outward motion of the wire at the full metered ratewithout pressure on the enamel in said chamber, and a compensation chamber to increase the head on the enamel sumciently to Vforce it to emerge with the wireV from said exit orifice at the full metered rate.

38. In a wire enameling machine, a supply of viscous enameling compound, means for moving the wire; a wire coating nozzle comprising a closed chamber surrounding the moving wire and supplied with a compound at a metered rate, an entrance orifice for the wire into said chamber, an exit orifice for the wire from said chamber, a wetting means to apply a less viscous wetting compound to the wire prior to reaching said entrance orifice, a wiper at said entrance orifice forming substantially an element of it to remove at this point substantially all of the adhering wetting compound whereby-a seal is formed and the air that -tends to be carried into said chamber on the moving wire is both excluded by the seal and Vconstantly removed with .the wiped oi! wetting compound.

39. In a -wire enameling machine. means to move the wire, a supply of viscous enameling compound, a supply of low viscosity prewetting iiuid,

`altwire coating device comprising a means to prewet the moving J wire withsaidiiiuid of 10W ViS- cosity, a wiper means to l.wiperoifi,stilista.;rtially all of the adhering'prewettingiiluidandntoform an air seal with.;the. wiped olf fluid, a chamberaboutA thewire contiguous-to` said wiper means and of '1' whichsaid wiper meansforms the inlet,a control meansto supply enameling compound ata metered rate to Y' said chamber, an exit .oriiice` of restricted .A dimension through which .the wire lleaving said chamber tends to carry out adher-v -ing enameling compound at less than theV metered supply rate, and a standpipe automatically to adjust the pressure in said chamber untilthepwire carries out compound at the metered supply rate. 40.y In a wire enameling machine, means for moving the wire, a supply of viscous enamel, a supply of uid prewetting compound, means to apply an air free coating of viscous enamel to the moving wire; comprising a means to, prewet the wire with said compound to minimize air bubble retention, an elastic' stripper, and means to pass the wire directly out of its coating of fluid compound into a mass of 'viscous enamel through an orice of said elastic stripper, whereby the fluid' compound is replaced on the wire by the viscous enamel without air contacting on the wire.

41. In a wire enameling machine, a supply of enameling compound, an oven, a draft seal for the foot of said oven comprising wire sheaves rimning in a pot of prewetting fluid, and an enameling compound application nozzle above said draft seal. y

42'. A coating nozzle for applying to the surface of an object a viscous fluid, in a thickness less than a natural flow coat, comprising at least one application orifice delivering the viscous fluid in i a natural flow coat upon a longitudinal element of the surface less in width than the total width to be coated, forming a stripe, and a spreader element adapted to widen and make thinner the stripe.

43. A coating nozzle for a wire comprising means to flow on the wire, a stripe of viscous fluid of predeterminable volume per foot and of natural or flow coat thickness, and means to assist the stripe of viscous uid to spread laterally to surround the wire.

44., Ina wire enameling machine, a source of compound, a nozzle comprising a bushing entirely surrounding the wire .and forming' a chamber `around it, a compound conduit leading into said chamber, a passageway at one end o f said chamber of asize to-clear wire of maximum diameter, a second passageway at the other end of said chamber having a size to impede passage of wire. of -maximum diameter with a. compound coating, a washer bearing against the wire below said first mentioned passageway, a prewetting pot below said washer, and a baking tube beyond said second mentioned passageway.

45.In a-wire enameling machine, a source of compound, means for moving the wire at a definite rate of speed vertically, a prewetting pot at Vthe lower end of said wire, a wiper above said pot for removing excess wetting substance from the wire. a nozzle having an orifice above said wiper, a chamber enclosing said nozzle and having alower and an upper opening through which -the'wire passes, said wiper, wire and the removed excess substance constituting a seal for the lower opening of said chamber, means for applying to the wire through said-nozzle a com-` plete-coating of compound within said chamber at la rate bearing a deiinite ratio to its rate of movement, and a baking tube above and-in close proximity to the upper opening of said chamber. 46. In a wire enameling machine, a source of compound, a nozzle comprising a bushing entirely surrounding the wire and forming a chamber around it, a compound conduit leading into said chamber, means for supplying compound to said conduit under pressure, a passageway at one end of said chamber of a width to permit clearance of wire of maximum diameter, a second passageway at the other end of said chamber having a size to impede passage o! wire of maximum diameter with a compound coating, a washer bearing against the wire below said iirst mentioned passageway, a prewetting pot below said washer, and a baking tube beyond second mentioned passageway. A

47. In a wire enameling machine, a source of compound, means for moving the wire at a definite rate of speed vertically, a prewetting pot at the lower end of said wire, a wiper above said pot for removing excess wetting substance from g the wire, a nozzle above said wiper, means for nozzle through which said wire passes.

48. In a Wire enameling machine, means for moving the wire, a nozzle comprising a bushing having a spiral groove through which the wire passes., and a compound duct orifice in said groove.

49. In a wire enameling machine, means for moving the wire, a nozzle comprising a bushing having a groove spirally around oi the wire, and acompound duct orice in said groove.

50. In a wire enameling machine, means for moving the wire, a nozzle comprising a' bushing having a groove spirally around 270 of the wire, and a compound duct orifice in said groove.

5l. In a wire enameling machine, means for moving the wire, a nozzle comprising a bushing vhaving a spiral groove through which the wire passes, a duct opening into said groove, and means for supplying compound under pressure to said duct.

52. In a wire enameling system, a supply of viscous compound, means to movethe wire, means to meter the compound to themoving wire, an application nozzle surrounding the moving wire having an exit orifice smaller than will pass withoutpressure the wire and the viscous compound at the metered rate.

53. In a wire enameling system, a supply of viscous compound, means to move the wire,

means to meter ,the compound to the moving` wire, an application nozzle surrounding the moving wire having an exit orifice smaller than will pass without pressure the wire and the viscous v compound at the metered rate, and a compensating pressure device to build up suillcient pressure to force the viscous compound through said exit orice at the metered rate,

54. The method of enameling wire which comprises moving the wire at a denite rate of speed, applying to the wire compound under pressure at a given point, and heating the compound prior to but near said point.

55. In a wire enameling system, a supply ot viscous compound, means for moving the wire, positive metering means to supply to the moving wire viscous compound at a certain rate, and thermal means'for reducing the viscosity of a small quantity of said compound near its point of application to the wire.

56. The method of coating an object which comprises; moving said object lengthwise, applying thereto a plurality of relatively narrow strips of compound at one point, the volume of compound per length of object being independent. and the width and thickness of the stripes being dependent on the speed at which the object is moved and the characteristics of the compound, and then wiping said stripes around said object.

57. A method of coating wire with a viscous liquid like varnish, without including air in the coating, which comprises: first, washing the aldsorbed air off the wire by a ilow of washing liquid; second, coating the wire by passing it immediately through a flow of coating liquid before it can contact with the air, the washing and the coating liquids being readily miscible and strongly wetting the wire; third, evenly distributing the coating liquid on the wire; fourth, drying the coated wire; fifth, collecting the washing liquid for re-use.

58. In a wire enameling machine, means to move the wire including two guide pulleys, means to remove adsorbed air from the wire in a flow of a washing liquid, an applicator through which the air-free and still damp wire passes to be covered with a. coating liquid, means to force through said applicator and onto the wire a controlled flow of coating liquid, the coating and the washing' liquids being miscible and both very wetting for the wire, an oven to harden the coating on the wire, a take-.up for the wire, and a vessel for collecting and settling the washing liquid so that it lmay be re-used.

` ARTHUR H. ADAMS.

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