US2233069A - Means for impregnating and coating articles - Google Patents

Description

Feb. 25, 1941. E. c. ATWELL MEANS FOR IMPREGNATING AND COATING ARTICLES Filed Nov. 20, 1937 7 Sheets-Sheet l Zahara 2212px! Feb. 25, 1941. E. c. ATWELL ,233.069

MEANS FOR IMPREGNATING AN D COATING ARTICLES Filed Nov. 20, 1937 7 Sheets-Sheet 2 Zvfionibr. Ji @1 07? WMYZ Feb. 25, 1941. E. c. ATWELL MEANS FOR IMPREGNATING AND COATING ARTICLES 7 Sheets-Sheet 5 Filed NOV. 20, 1957 Feb. 25, 1941. E. c. ATWELL MEANS FOR IMPREGNATING AND COATING ARTICLES 7 Sh6etSSheet 4 Filed Nov. 20, 1937 Feb. 25, 1941. E. c. ATWELL MEANS FOR IMPREGNATING AND COATING ARTICLES Filed Nov. 20, 1957 '7 Sheets-Sheet 5 1172 11731.- 11?)??? WZWZZ u m m n u m o m m "W O O O O O 0 CW0! W Mum WIN a uh wooooooom Feb. 25, 1941. E C ATwELL 2,233,069

MEANS FOR IMPREGNATING AND COATING ARTICLES Filed Nov. 20, 1937 7 Sheets-Sheet 6 gian /7014' jZiZ J PYZZZZZ ZZ Feb. 25, 1941. E. c. ATWELL MEANS FOR IMPREGNATING AND COATING ARTICLES 7 Sheets-Sheet 7 Filed Nov. 20, 1937 Patented Feb. 25, 1941 UNITED STATES PATENT OFFICE MEANS FOR IDIPBEGNATING AND COATING ARTICLES Rhode Island Application November 20, 1937, Serial No. 175,687

32 Claims.

This invention relates to an apparatus for impregnating and coating fibrous articles, particularly perforated paper tubes used as supports for textile filaments, yarn and the like during varil ous wet and dry processes.

In the following specification and claims the word tube" is used in a generic sense to indicate any form of yam-receiver or -carrier constructed from fibrous material or the like and 10 the term coating solution" is used broadly to designate any composition suitable for impregnating or coating the tubes to substantially fill and seal all voids and render them smooth of surface and impervious to fluids.

One object of the invention is to provide an apparatus for impregnating and coating the tubes with a resinous or equivalent compound, removing the volatile solvents from the coating and finally baking the residual resin solids to a desired degree of hardness, insolubility and infusibility.

Another object of the invention is to provide means for continuously impregnating fibrous tubes consisting in preheating the tubes to expel air and moisture from the interstices or voids therein and replacing the air with the compound, while at the same time lightly coating the external faces of the tubes with a minimum amount of resin to secure a smooth continuous surface thereon.

Another object of the invention is to provide means for removing the solvent contained in the solution on the impregnated and coated tubes in a manner which avoids the formation of pin- 35 holes and blisters and which consists in circulating air at gradually rising temperature around the tubes, and thereafter causing the remaining resin solids of the applied solution to be converted into an insoluble and infusible state by the circulation of air at high temperature.

Another object of the invention is to provide an apparatus for continuously carrying out the above in which all of the several operations are 45 effected automatically.

Another object of the invention is to provide an apparatus of the type indicated adapted to operate efficlently on a large number of tubes treated simultaneously and one which is simple so and compact in structure, requiring a minimum floor area.

Further objects of the invention are set forth in the following specification which describes, by way of example, the steps of a preferred method 55 and an apparatus adapted therefor as illustrated by the accompanying drawings. In the drawings:

Fig. 1 is a side elevatlonal view of the improved tube-impregnating and -coating apparatus;

Fig. 2 is a transverse sectional view of the apo paratus taken on line 2-2 of Fig. 1;

Fig. 3 is a transverse sectional view of the apparatus taken on line 33 of Fig. 1:

Fig. 4 is a transverse sectional view of the apparatus taken on line l4 of Fig. 1:

Fig. 5 is a longitudinal sectional view of the chambered housing of the apparatus showing, more or less diagrammatically, the manner in which the tubes are conveyed through the different compartments thereof during the various steps in their treatment;

Fig. 6 is an enlarged longitudinal sectional view illustrating a portion of the interior of the apparatus and showing the loading, preheating, and impregnating-and-coating compartments:

Fig. 7 is an enlarged transverse sectional view of the impregnating-and-coating compartment taken on line 1-1 of Fig. 6;

Fig. 8 is a side elevation of a portion of a tubecarrying or supporting frame;

Fig. 9 is an end view of the same part-sectional on line 9-9 of Fig. 8:

Fig. 10 is a detailed plan view of one of the holders of the carrying frame taken on line Ill-l 0 of Fi 8;

Fig. 11 is an edge view of one of the baflle-plates carried by and movable with the tube-conveying means:

Fig. 12 is a fragmentary plan view of a portion of the tube-conveyor; 35

Fig. 13 is a side view of one of the driving sprockets for the conveyor;

Fig. 14 is a diagrammatic view showing the main operating parts of the apparatus and illustrating the controlling means therefor:

Fig. 15 is a diagrammatic view showing the electrical circuit for the controlling unit in detail; and

Fig. 16 is. a diagrammatic view showing an alternative electrical circuit for controlling the ac- 5 tion of the main operating parts of the apparatus.

In dyeing and otherwise treating yarn masses with fiuids the yarn is sometimes wound onto perforated paper or fiber tubes and processed in package form. For the sake of economy it is 50 desirable to reuse these tubes. It is therefore important that the tubes be impervious to fluids and free from projecting fibers or other protuberances liable to catch and injure the yarn as it shifts on the tube in wetting out, or as it is un- 55 wound therefrom after treatment and drying. To adapt the tubes for reuse. it is necessary that the voids or interstices therein be substantially filled and sealed and that the filling or sealing material be strong, yet sufiiciently flexible to withstand deformation without cracking. In this manner the formation of cracks which would permit penetration of dye-liquid or other fluids into the fibers of the tubes is prevented. Tubes provided with a continuous coating but without impregnation invariably crack when deformed slightly, thereby permitting the fluids to enter the voids and render them unfit for continued reuse.

In practically all previously used methods of coating and impregnating articles a large floor space is required for the several units including a loading position, a preheating chamber, a dip tank, 'a drain board, a solvent-removing chamber and a baking oven. In addition to the high cost or iioor space is the added expense of separate large units and the large number of operators required to handle the apparatus.

It is the aim of the present invention to provide an efficient apparatus constituted as a single machine for continuously and automatically carrying out the separate steps of the improved process herein described. The first step in the improved method is that of preheating the tubes to expel the normal regain of moisture and part of the air pocketed in the interstices between the fibers of the material 01 the tubes to create a partial vacuum therein. The relatively hot tubes are thereafter immersed in a resinous solut on at a temperature lower than that oi the tubes to cause the solution to be rapidly drawn into the interstices or voids between the fibers to completely impregnate the material of the tubes and coat the surface thereof. The surplus solution is then permitted to drain from the tubes under control by gradually removing the supply of solution from contact with the tubes. The impregnated and coated tubes are finally subjected to a series of drying operations by circulation of heated air to evaporate the solvent at a slow rate to prevent blistering and to cause the deposited resin to adhere firmly to the surfaces of the tubes. The temperature of the circulating air is gradually raised during the solvent removal process until it finally reaches a degree capable of baking the resin solids. The tubes are baked for a period to render the deposited resin insoluble and infusible. This cycle of operations may be repeated automatically to apply the necessary number of impregnations and coatings to the tubes, after which they are ready for immediate use. Through the use of the improved method and apparatus, to be next described in detail, the tubes are impregnated and. coated thoroughly and evenly and their coating prevented from cracking,

Referring to Figs. 1 to 4 of the drawings, the apparatus proper is supported by a framework 2 comprising pairs of opposite stanchions or column; 8 which rest upon the floor and are connected by upper and lower cross-struts I and 5. The pairs of uprights 3 are joined together by a track 20, to be later described. and a plate 5 which is fastened to the top of the cross-struts I and extends downwardly along the outer pairs of uprights 3 to which it is secured. The plate 6 is also fastened to the bottom of the crossstruts 5 to provide a rigid rectangular structure. Extending in spaced, parallel relation to the plate 6 is a second, outer plate 8 joined to the plate 5 by side plates 5 to form a housing ill of rectangular cross-section, see Fig. 2. Through the described construction a continuous rectangular duct is provided through which the paper tubes are progressively advanced in a closed circuit, see Figs. 5 and 6, in the manner and for the purpose as later explained.

Spaced a short distance from the inner and outer plates 6 and ii of the housing or duct iii, in parallel relation thereto, are perforated plates l4 and I5 suitably attached to the side plates 9. The cross-struts l and 5 carry I-beam sections ii to which are secured a pair of spaced angle-irons ill, see Figs. 5, 6 and 7. the outer laterally-extending flanges 20 of which cooperate to form a closed rectangular track extending throughout the full length of the duct or housing. The vertical and horizontal extensions of the rectangle are Joined by arcuate sections indicated at I9. The track 20 aids in adding strength and rigidity to the frame 2. Suitably fastened to the various plates forming the housing or duct in are fixed partition baiiie-plates 2|, 22 and 23 which are spaced along the interior of the duct in the order illustrated in Fig. 5 to adapt them to cooperate with bames on the conveyor 25 to form a series or compartments into which groups of the tubes are progressively conveyed to receive various treatments.

The tubes are advanced into and through the various compartments by means of an endless conveyor 25 adapted to travel along the track 25. As shown in Figs. 7, 8, 12 and 13, the conveyor 25 is in the form of an endless chain comprising a series of channel-iron bars or battens 26 extending laterally within the housing or duct Ill and hingedly connected by links 28 pivotally joined by pins 28. see Fig. 12. As shown in Figs. 8 and 9, the channel-iron bars 26 carry bifurcated brackets 50 in the opposite forked arms 3i of which are bearing pins 32. Journaled on the pins 32 are rollers 33 straddling the track 20 to adapt them to roll therealong as the conveyor 25 travels in the housing or duct ill. The rollers 22 are constructed from bronze or other staticeliminating material to prevent frictional sparks and thereby avoid a fire hazard. The conveyor 25 may be driven by pairs of sprockets 35, one of which is shown in Fig. 13, the sprockets being keyed to a transverse shaft 36 and adapted to receive the channels 28 in the spaces between their teeth. The shaft 38 is journaled in bearings 31 secured to a platform H projecting laterally from the upper cross-struts l of the framework 2, see Fig. 1. The shaft 26 carries a spur-gear 3B which is driven from a train of speed-reduction gears indicated at 39 in Fig. 1, the gear-train being driven in any suitable manner from an electric motor 40 or other source of power. Although the conveyor 25 is herein shown as arranged to be driven at one location in its path of travel it may be driven at a plurality of points. The travel of the conveyor 25 within the duct I0 is intermittent to successively present the batches of tubes to the spaced stations or compartments where they halt for a predetermined interval, and for this purpose the motor 40 is periodically energized by means oi" a time-control unit to be later described.

The conveyor 25 carries bailie-plates 42 which register with the baiiles 2i, 22 and 23 of the duct II) when the conveyor is at rest to completely enclose the spaces between the perforated plates l4 and i5 of each pair to form four-walled closed compartments. As shown in Fig. 11 the plates l2 are riveted to angle-irons 53 carried by the bars 25 of the conveyor 25 and braced by angular strips 4|.

The tubes to be coated are carried by the conveyor 25 arranged in multiple rows between the baffle-plates 42, being supported on frames 5|! suspended from the conveyor-bars 25. The frames 50, shown in detail in Figs. 8 and 9 comprise upper and lower horizontal channel-irons or bars 5| and 52 mounting a series of tube-holders 53. The tube-holders 53 may take various forms and, as herein shown, each holder comprises three equally spaced V-shaped wire arms 54, having their ends suitably connected together and fastened to the channels 5| and 52, see Fig. 10. The tapered sides of the wires 5| are adapted to enter the interior of the tubes t to contact the inner rim at their ends at three points only. In this manner the outer yarn-engaging surfaces are fully exposed to the coating material and left free from irregularities of marks made by contact with the holder. The points of contact of the holder on the inner rims at the ends of the tubes are small in area so that the holders are readily freed from the tubes after dipping and baking.

To load the tubes 1! onto a frame 50 the channel-bar 52 is placed on a support with its holders 53 projecting upwardly as indicated in Figs. 8 and 9. Tubes t are then applied to the holders 53 and the bar 5| placed thereover with its holders 53 engaging the upper rims of the tubes. At the ends of the bar 52 are rods 56 having their upper ends threaded and adapted to project through slots at the ends of the upper bar 5|. Wing-nuts 51 are screwed onto the threaded ends of the rods 56 to tie the bars 5| and 52 of the frame 50 together and retain the tubes t securely in place on their holders. Each complete frame 50 carrying a series of tubes t is attached to one of the conveyor-bars 26, at a station to be later designated, by means of studs 58 on the bar 25 passing through slots 59 in the upper bar 5| with wing-nuts 6|! screwed onto the studs, see Figs. 7 and 8.

It has been explained that the rectangular conduit or duct I is divided into a plurality of compartments by the baffle-plates before described. In the present embodiment of the invention seven compartments are provided as indicated in the drawings by the reference characters a, b. c. d, e, J and g. The compartment a constitutes the loading and unloading station at which point the loaded frames 50 are attached to and removed from the conveyor 25. For this purpose the front wall 8 and the perforated plate l are omitted from this compartment to permit entrance of the tube-carrying frames 50. The opening in compartment a may be closed when desired by means of a sliding door indicated generally at B2 in Fig. 1. At compartment a the perforations in the upright plate II are omitted, see Fig. 6, to seal the interior from the atmosphere when the door 62 is closed as illustrated in Fig. 1.

Compartment 1) constitutes the preheating chamber in which the tubes t are first heated to a relatively high temperature to drive off the normal moisture content or regain and a portion of the air which is pocketed in the interstices between the fibers of the material of the tubes. Heated air is introduced into the top of the compartment b through a pipe or duct 69 forming a continuation of a larger pipe or header which is connected to an air-heater and fan to be later described. Upon entering the chamber b the hot air is drawn downwardly through the perforations in the plate I4, circulated around the tubes 1. suspended therein. and thence drawn downwardly through the perforations in the plate l5, from which point it exhausts through a return pipe 1|. After preheating, the tubes t are transported to compartment 0 where they are impregnated and coated in the manner as later explained. During the impregnating and coating operation, air at room temperature is circulated through the chamber 0 to carry away the explosive admixture of solvent vapor and air. The air enters manifolds formed by the extended sides of the compartment c through pipes 13 connected to a fresh air duct or header I4 and thence passes through perforations in the side walls 9 provided at this station, see Fig. 7. The air circulates around the tubes t, passes upwardly through the perforations in the plate I4 and exhausts through a pipe or duct which is connected to an exhaust header 15. Fresh air is supplied to the intake header ll by means of a motor-driven fan 'll, see Figs. 1 and 2, which draws from the room atmosphere through a filter 18. The saturated air upon entering the exhaust-header I5 is drawn into a housing I9 by a motor-driven fan llll and forced into an exhaust pipe 8| leading to a stack communicating with atmosphere above the building, in which the apparatus is located, see Fig. 3.

After being impregnated and coated the tubes t are conveyed to compartment d where air at room temperature is circulated around the tubes to evaporate part of the solvent thereon and cause the resin to congeal. The compartment d is twice the size of each compartment a, b and c and adapted to enclose two lots or batches of tubes. Fresh air is forced into the compartment d by way of a pipe 83 connected to the air-supply duct or intake-header l4 and passing upwardly through the perforated plate i5, circulates around the tubes t and is thence drawn upwardly through the plate M and into a pipe 54 connected to the exhaust-header 15.

The tubes t are next conveyed to compartment e which is similar to compartment d in that it is adapted to contain two lots of tubes. Air heated to a temperature of approximately 150 F. is circulated around the tubes while they remain in compartment (1 to cause more solvent to pass off from the tubes and leave a deposit of resin thereon, the applied heat tending to further aid in hardening the coating. Fresh air in the header 14 passes through a heater 85 comprising steamcoils and is forced into a pipe 86 leading to compartment e. The heated air is then drawn upwardly through the perforated plates l5 and I4, circulating around the tubes t and passing through a pipe 81 connected to a larger pipe or duct 88 leading to the housing 19, fan 80 and exhaust-pipe 8|.

After being treated in compartment e the tubes 1! are conveyed to a double compartment 1. Air heated to a temperature of approximately 300 F. by steam-coils in a heater 9!! is forced into the header 10, previously mentioned, and through a pipe ill connected thereto and communicating with the compartment 1. The hot air upon entering the compartment 1 is forced through the perforated plate It, circulated around the tubes t and then drawn outwardly through the plate l5 into the exhaust-pipe or duct 88. Fresh air is drawn through a filter 93 and into the heater 90 by means of a motor-driven fan 94, see Figs. 1 and 4. An exhaust-pipe 95 connected to the lower end oi! the heater is provided with a damper 98 which by changing its position regulates the amount of fresh air introduced into the system in accordance with requirements. The remaining solvent 0! the deposited resinous solution is completely evaporated in compartment I and the solvent-free resinous coating remains as a sticky and viscous mass.

A relatively long compartment 0 extends from compartment 1 upwardly. thence horizontally and then downwardly to connect with the loading compartment a, this compartment being capable of containing for example, ten lots or groups of tubes t. In compartment 0 the deposited resin is baked onto the tubes t to the required degree of hardness, insolubility and iniusibility. Since all the solvent is removed from the tubes before they enter compartment 0. the hot air introduced into this compartment may be partially recirculated without danger of its becoming saturated with combustible solvent to present a fire hazard. The air heated to a temperature of approximately 300 F. in the heater 90 is forced upwardly into the header 10 by means of the blower or fan 04 and enters the compartment g at spaced intervals therealong by way of branches or intake-pipes I00. lIlI, I02, I03 and I04 communicating with the header and compartment. The hot air passes through the compartment 9 inthe same manner as previously explained and exhausts into return pipes or branches I05, I00, I01, I00 and I00 connecting the compartment with the exhaust header II which returns it to the heater 90 to be recirculated.

The heated air which is recirculated through the compartment 9 contains vapors oi resin-reaction products but no solvent, and to efl'ect maximum efllciency this air, instead of being exhausted directly into the atmosphere, is passed through the compartment 1 to evaporate solvent from the tubes stationed therein and through the compartment b to preheat the tubes.

The inlet pipes 60, I3, 83, 8B and SI leading to the compartments 2), c, d, e and I, respectively, are provided with manually-operable dampers IIO. see Fig. 1, by means of which the flow of air through the various compartments may be regulated to obtain the desired distribution of air volumes. The compartments may also be provided with automatic temperature-control units, not herein shown, for maintaining the proper degree of heat by regulating the amount of steam introduced into the air-heaters 05 and 90. As a safety measure, steam pipes III, indicated in Fig. 1, having thermostatic valves may be connected to the interior of each compartment to introduce steam thereinto should the temperature rise sufliciently to cause fire from combustion of the solvent. The temperature control units may be connected to operate a bell, light or other signal to indicate to the attendant which of the compartments is overheated. In the impregnating and coating compartment 0 is a pipe II2, see Fig. l, which may be connected to a supply of carbon dioxide or other fire-extinguishing gas and provided with a i'usible link adapted to rupture and release C0: gas when the temperature rises to a predetermined degree. These latter connections are not herein shown in detail, however. as they form no part of the present invention.

It has been stated that the invention contemplates an improved method and means for impregnating and coating the tubes. Figs. 6 and upon the upper the conveyor-driving 7 illustrate the improved tube-immersing means as comprising a rectangular tank I20 for con- The tank closing tank |2l with I20 seats in a larger enits flanged rim I22 resting edges of the latter. Through this arrangement a space I20 is provided between the two tanks I20 and I2I for containing cold water which is employed for cooling the coating solution. The tanks I20 and I2I are supported by a table or platen I24 at the upper end of a piston I20 operated by a hydraulic lift of usual construction indicated at I20 in Fig. 14 as built into the floor on which the apparatus is erected. The raising and lowering o! the piston I2! is controlled by a suitable time-controlled switch to be later described. The coating compound, indicated at C, is forced into the tank I20 through perforations in branches I28 oi a pipe I20 connected to a motor-driven pump I21 supported on an extension of the platen I24, see Figs. 1 and 6. The coating compound 0 is recirculated the pump I21 by way of a vertical standpipe I30 and as the liquid is depleted during the operation of the apparatus it is replenished from a suitable storage tank connected to the pipe I30 by means of a flexible pipe I2I, see Fig. 1. The liquid compound C flowing to the pump I21 is preferably strained through a suitable filter I32. By constantly recirculating the compound C the viscosity and temperature of the supply in the tank I20 is maintained substantially uniform from top to bottom. The cold water used for cooling the coating compound C in the tank I20 is circulated through the tank |2i under pressure and is connected to inlet and outlet pipes I 30 and I30 communicating with the interior of the tank.

Fig. 14 illustrates diagrammatically the means for operating the tank I20 and intermittently driving the conveyor 20. The means for operating the tank I20 consists of a pump I40 driven from an electric motor I. The pump I40 draws liquid from a tank or reservoir I42 and forces it through a pipe I40 into the cylinder I44 of the hydraulic lift I20 to raise the piston I20 and elevate the tank I20 into position to cause immersion of the tubes t in the solution 0 contained in the tank. Intermittent operation or the pump-motor I is effected by a controlling unit indicated at I40. The controlling unit. which will be later described more in detail comprises, in general, a series of coils which are intermittently energized during the operation of the apparatus to close and open the circuits for motor 40, tank-elevating motor I" and other lnstrumentalities.

Incorporated in the controlling unit I45 is a timing device which, through means to be later described, operates a valve I40 in the pipe I41 connected between the cylinder I44 and the reservoir I42. When the valve I40 is opened the liquid flows from the cylinder I44 through the pipe I41 at a reduced rate as controlled by a restricted opening I40 in the pipe whereby to cause the tank I20 to descend slowly and the surplus solution on the tubes t to drain directly into the supply C in the tank. During the lowering of the tank I 20 a check-valve I40 in the inlet-pipe I43 closes. The raising of the tank I20 is also controlled from the timing device which acts, when the conveyor 20 is at rest to energize the pump-motor I to elevate the tank. Operation of the timing device is intermittently effected by two electrical switches or circuit-breakers I13 and I61 positioned In the path of movement of the tank I20 and adapted to be opened and closed thereby as the tank ascends and descends. Through the provision of the switches I10 and I61 operation of the conveyor-driving motor 40 can be eflec-ted only when the tank I20 is in lowermost position.

In operation, the conveyor 25 is caused to travel within the conduit I by energizing the motor 40 and after the conveyor has positioned the tubes t within the various compartments its movement is automatically interrupted by a switch I66 operated by movement of the conveyor, the switch acting to open the circuit to the motor. The tank is then elevated by the motor-driven pump I40 and the tubes immersed in the solution C contained in the tank, the extent of upward movement being controlled by the limit-switch I10. The timing device acts to maintain the tank I20 elevated for a predetermined period after which the solenoidoperated valve I46 is opened to permit the tank to descend. When the tank I20 reaches its lowermost position the switch I61 acts to close the circuit to the conveyor-driving motor 40 and the timing switch restarts the cycle of operations above explained at any predetermined time period after the opening of the solenoid-valve I46.

In the electrical diagram illustrated in Fig. 15 are magnetic coils I65, I66, I69, Ill, I12, I15 and I 11 whose function is to operate suitable circuit-breakers for opening and closing contacts I65 I65 I68 -I66", I69 I69 I1I -l1l', I12I12 ll2'=-I12 I15 -I15 --II6=-I15 I15 and the valve I46 respectively. Timing relay coils I14 and I16 are also provided for opening and closing contacts "4 -414" and I16I15" respectively.

Assuming that the apparatus is at rest. the various coils above described will be deenergized and the circuit-breakers which are operated by the respective coils will assume the positions shown in Fig. 15 to open and close the various contacts and the circuits in which the contacts are positioned. The tank I20 will be in lowermost position to open the switch I61, the conveyor will be at rest, the conveyor-switch I66 open and both electric motors 40 and I will be idle.

To start the cycle of operation of the apparatus the switches I6I, I62 and I10 are closed. Electric current will then flow from the power-line I60 through IN and I62 and coil I65 to energize the latter and cause bridging of the contacts I65 and I65". Closing of contact I65 maintains the coil I65 energized even though the switch I6I is again opened. When contact I65 is closed electric current passes therethrough to the various circuits. It will be noted by reference to the diagram that contacts I69 and I12 are closed, so that current will pass to and energize the coil I15 thereby closing contacts I15, I15 and I15 to energize and cause the conveyor-driving motor 40 to travel the conveyor 25 within the conduit III to position the groups of tubes t within the several compartments for treatment. As the conveyor 25 starts its travel the limit-switch I66 is closed to energize coll I60 and thereby close contact I68 whereby to permit flow of current to the coil I15 even though switch I10 is opened.

As soon as the tubes t are properly positioned within the compartments limit-switch I66 is opened by the conveyor 25 to deenergize coil I66 and open contact I66 thereby deenergizing coil I15 to permit contacts I15, I15 and I15" to open and arrest the operation of the motor 40 and the travel of the conveyor 25. During the operation 01' the motor 40 and the travel oi the conveyor 25 electric current passes through contact I16 and I15 to energize the coil "I and close contacts I1I and Ill". when the coil I15 is deenergized current may still flow to the coil "I by way of closed contacts I66 and Ill. The circuit through contacts I16", I14, Ill", I16" and closed switch I to the coil I12 is closed to energize coil I12. As coil I12 is energized it acts to close contacts I12", I12 and "2* to connect the tank-elevating motor I with the power-line I60. In this manner the motor I drives the pump I40 to force liquid into the cylinder I44 and raise the tank into operative position. The tubes t are thus immersed in the solution C and the switch I13 is opened by engagement with the tank I20 to disrupt the flow of current to the coil I12. Contacts I12 I12 and I12 will then open to stop the motor I. As before explained the conveyor driving motor 40 has already stopped so that for the moment the complete apparatus is at rest and the tubes t remain immersed in the solution C. At the start of the upward movement of the tank I20 the limit-switch I61 is closed and current flows to and energizes coil I69 to open contact I69 and close contact I60".

When the operation of the apparatus was initially started by pressing the start button I6I current flowed through contact I16 to energize the timing-relay coil I14. However, until the proper time the adjustable relay I14 does not operate on the contacts I14 and "4 and the tank I20 remains in uppermost position to coat the tubes. After the tank I20 has remained elevated for a predetermined period of time the timing-relay I14 acts to open contact I14 and close I14 to complete the circuit to the solenoid coil I11 by way oi closed contact I69". As before explained coil I11 when energized, opens valve I46 to permit the tank I20 to descend slowly. When the tank I20 reaches its lowermost position the limit-switch I61 is again opened to deenergize coil I60 and cause contact I66 to close and I69 to open. When I69 opens the tank-lowering control-coii I11 is deenergized.

When contact I14 was closed by the action of the timing-relay I14, the circuit for the second timing-relay I16 was closed. The relay I16 is so adjusted that after the tank I20 has remained in its lowermost position for a predetermined period the relay closes contact I16 and opens I16. Closing of contact I16 completes the circuit to the coil I15 by way of contacts I69 and I12. As coil I15 is reenergized contacts I15, I15 and I15 are closed thereby and the mottor 40 again acts to drive the conveyor 25 to advance the groups of tubes within the conduit III. As the conveyor 25 starts its movement limit-switch I66 is again closed to energize coil I68, thereby closing contact I68 to complete the circuit to coil I15 to maintain the motor 40 operative.

Due to the fact that contacts I16 and I68 are opened by the relay-coil I16 and coil I68, respectively, coil I" is deenergized to open contact I1 I. It is then impossible for current to pass to the energizing coil I12 for the tank-motor I4I. Contact "I" in opening prevents flow of current to the timing-relay I14 by way of contact I15. Flow of current to the relay-coil I14 is further disrupted by the opening of contact I16 as effected by the timing-relay I16. Due to the fact that the circuit for the relay I16 is opened the latter is rendered inoperative.

As the conveyor 25 travels within the conduit in the electrically-operated controlling means acts periodically to arrest its motion, whereafter it functions to elevate the tank I28, time the period the tank remains elevated, lower the tank, time the period the tank remains in lowermost position, and finally restart the conveyor in the manner and for the purpose as before explained.

Fig. 16 shows an alternative means for controlling the operation of the apparatus. With this latter form of controlling means intermittent operation of the pump-motor "I is effected by a cam I8I fast on a shaft I82 which is slowly and continuously rotated during operation of the apparatus by a synchronous clock or timing-device I88 in circuit with an electrical power-line I88. The cam I8I is adapted to contact with a rockable lever I84 carrying a mercury-type switch I to cause the latter to tilt and close the circuit from the power-line I88 through a normally closed switch I88 whereby to energize the motor I. As the tank I28 is raised to immerse the tubes in the solution it operates the switch I to open the circuit to the motor I. After a predetermined period the piston I28 is slowly lowered by gravity through the relief means described in connection with the embodiment illustrated in Figs. 14 and 15. I

The tank I28 is held in raised position for a definite interval to cause the solution to thoroughly penetrate into the material of the tubes t. A second cam I81 on the rotating shaft I82 is adapted to tilt a lever I88 carrying a mercurytype switch I89 to close a branch circuit from the power-line I83 to the solenoid Ill. The solenoid I'I'I operates to open the relief valve I48 in the return-pipe I" to permit the liquid in the cylinder to return to the reservoir I42 through the restricted passage I48. The valve I48, which is normally closed, serves to prevent the return of liquid from the cylinder I44 to the reservoir I42 during the operation of the pump I48.

The shaft I82 is rotated once during a predetermined period of time, for example, fifteen minutes, and the cam III is so designed that it holds the switch-lever I84 depressed for approximately one minute during each fifteen-minute period to raise the tank I28 into operative position. During the one-minute interval and for ten minutes thereafter the switch I89 remains open and flow of current to the solenoid I'll is conse quently disrupted. The flow of liquid through the pipe I4! is prevented during this time by the solenoid-valve I48 which is held closed by suitable mechanism within its housing.

After the tank I28 has remained elevated for the required ten minutes, or any other predetermined interval, the cam I81 contacts the arm I88 of the switch I89 and rocks the latter to the position indicated by the dotted lines in Fig. 16 to close the circuit to and energize the solenoid I'I'I whereby to open the valve I48. The solenoid Ill is energized for approximately three and onehalf minutes, this period of time being suilicient to cause lowering of the tank I28 to inoperative position. As before explained, the slow downward movement of the tank I28, as controlled by the restricted passage I49, causes the surplus solution on the tubes t to drain back into the supply 0 in the tank.

As indicated at the left in Fig. 16, the motor 48 for driving the conveyor 25 derives its energy from the power-line I88, one branch oi the circuit leading directly to the motor. Two switches or circuit-breakers I98 and 288 are connected in series in the other branch leading to the motor 48. The switch I98, which may be of any suitable construction, is herein shown, by way of example, as of the plunger type having a piston I8I slidable in a casing and adapted to contact with opposite terminals I92. The piston I9I is normally held raised from contact with the terminals I92 by a coil-spring I98 pocketed in the switch-casing. The switch I92 is located directly beneath the tank I28 and as the latter is lowered to inoperative position it engages and depresses the piston I9I to cause the latter to contact with the opposite terminals I92 and thereby complete the circuit to the switch or circuit-breaker 288.

The switch 288 is herein shown as of the plunger-type having a piston 28I slidable in a bore in the switch-housing and adapted, when in uppermost position, to bridge the gap between opposite terminals 282 to complete the circuit to the conveyor-driving motor 48. The piston 28I is held raised by a coil-spring 283 pocketed in the housing beneath the plunger. The switch 288 is preferably constructed in the form of a dash-pot, the housing containing a supply of dielectric fluid adapted to pass quickly through an opening 284 in the piston when the latter is depressed and to flow slowly through a restricted opening 288 therein when the piston is raised by the spring 288 whereby to retard its upward movement. A suitable check-valve 288 may be provided for closing the larger opening 284 in the piston during the upward movement thereof.

The piston 28I of the switch 288 is connected to one arm 288 of a bell-crank lever 289 pivoted at 2I8. The other arm 2 of the lever 288 is adapted to be engaged by pins 2I2 spaced along and projecting from the conveyor 25 as the latter travels within the housing or conduit.

Assuming that the piston 28I of switch 288 is in uppermost position and the piston I8I of switch I98 is in lowermost position, the circuit to the motor 48 is closed and the motor drives the veyor 25 will engage the arm 2 of the bellcrank lever 289 to rock the latter to force the piston 28I of the switch 288 downwardly whereby to break the circuit to the motor 48. Due to momentum of the conveyor the pin H2 is carried past the point of contact with the leverarm 2 and the piston 28I starts to move upwardly toward the terminals 282. This return motion is delayed by the action of the dash-pot. however, and before the piston 28I is alined with the terminals 282 the time-control unit I88 acts through the cam I8I and switch I 98 to energize the motor I and pump I48 to cause elevation of the tank I28 into operative position. As the tank I28 is elevated the piston I9I of the switch I98 rises and breaks the contact between the terminals I92 to open the circuit to the conveyordriving motor 48 so that when the switch 288 is eventually closed the switch I98 is open and the motor 48 remains idle. The complete apparatus having been described in detail its method of operation will next be explained.

To prepare the apparatus for operation the operator first closes a suitable manually-operated switch in the electrical control-circuit of the type shown in Figs. 14 and 15 or Fig. 16, and takes a position in front of the loading compartment a to attach the frames 58 carrying the tubes 1! to the conveyor 28 in the manner before explained and illustrated at :r in Fig. 6; it being understood that the tubes have previously been mounted on the frames. A fifteen-minute period may be provided for loading a complete group of tubes, comprising, for example, fifteen frames each holding twenty-four tubes, onto the conveyor 25 and at the end of this period the tank I20 has been lowered to close the circuit to the conveyor-driving motor which transports the first group of tubes t into compartment b. Through the instrumentalities before described in connection with either form of electrical controlling means the circuit to the motor 00 is then opened to arrest the travel of the conveyor. when the conveyor comes to rest the baiiie-plates 42 carried thereby will register with the baflle-plates 2|, 22 and 20 to close the ends of the compartments. The heated air circulated through the compartment 1) preheats the tubes 1: and drives oi! the normal content of moisture and part of the air contained in the interstices between the fibers of the material thereof. During this preheating period another group of frames with tubes mounted thereon are attached to the conveyor 20.

At the end oi a predetermined period of time, for example, eleven minutes, the controlling means acts to energize the solenoid I11 to open valve I40 and permit the tank I20 to descend. After the tank I20 has remained in its lowermost position for a predetermined period the timing means operates to close the circuit to the conveyor-driving motor 00 and the heated tubes is moved into compartment 0. The tubes are transported into the compartment in approximately one-half minute and at the end of this time the controlling means again acts to energize the motor III to elevate the tank I20, it being understood and lowering of the tank is automatically regulated during the entire operation of the apparatus by the time-control units.

As the hot tuba t depending from the conveyor 25 are immersed in the cool impregnating compound 0 contained in the tank I20 the vacuum occurring in the interstices of the material of the tubes causes the solution to be drawn into the voids to impregnate the inner fibers of the material. The outer surfaces of the tubes also .receive an initial coating which tends to cover the outer fibers and bind them in place against the tubes. After the required ten minute coating and impregnating period the tank I20 is automatically lowered at a slow rate to permit the liquid to drain therefrom. Through this provision the surplus solution is permitted to drain slowly and evenly down the surfaces of the tubes and directly into the supply in the tank I20 without excessive dripping. During the lowering of the tank I20 the exposed parts of the tubes are contacted by the air circulating through the compartment. The air serves to evaporate part of the volatile solvent therefrom and thereby congeal the solution to a slight degree so that streaks or runs" and "bottom rings" usually appearing on tubes which are coated or impregnated by usual methods are avoided. The fresh air replacing the saturated air and combustible gases in the compartment prevents any fire hazard.

With the tank I20 in lowermost position the controlling means acts through the instrumentalities previously described to energize the motor 40 to again travel the conveyor 25 to transport the group of tubes t into the double compartment d where fresh air at room temperature is circulated around the tubes to evaporate the solvent and exhaust it into the pipe 0i. At the first group of.

that the intermittent raising" next indexing movement of the conveyor 25 the first group of tubes moves into the second hall of the compartment d to receive a continuation of the treatment Just described, it being understood that during each treatment of the first group of tubes t a fresh group is placed on the conveyor and the succeeding groups follow in order to receive the successive steps in the treatment.

The first group of tubes t is transferred from compartment d into the double compartment e where it is subjected to treatment with iresh air preheated to 150 F. during a double-length period. The warm air passing around the tubes t further aids in evaporating the solvent without causing blistering of the residual solids. When the tubes have remained in compartment e for a double-length period most of the solvent is evaporated and it remains only necessary to remove the small remaining portion thereof and bake the resin solidly by applying a relatively high degree of heat thereto. The passing of hot air of 300 F. through the next double compartment 1 and multi-station compartment g causes evaporation of the remainder of the solvent and the residual solids are meanwhile baked and solidified to the desired degree.

After completing the cycle of operations as above explained as the first batch of tubes is about to reenter the loading compartment 11. the sliding door 52 is closed to seal this compartment from the atmosphere to maintain the tubes hot. The cycle of operations may then be repeated with little or no attention on the part of the operator to automatically apply a second coat of resinous material to the tubes whereby to fill in or seal any voids left by the evaporation of solvent in the previous operation.

Two coating operations are preferably performed using a. solution of maximum viscosity and a solid content commensurate with complete and rapid impregnation to build up a nearly continuous exterior coating. This coating, however, may be insuilicient to present a perfectly smooth and impervious surface; in which case a third coating is applied to fill up and seal the voids caused by the last solvent evaporation and to build up an exterior film of sufficient depth to cover any remaining fibers or other projections liable to catch and injure the delicate fibers of the yarn wound on the tubes. As the final coating is completed the tubes are removed from the conveyor as they reach the loading station, being replaced with new tubes to render the operation of the apparatus continuous. It will be readily understood that the number of impregnating and coating operations depends upon the porosity of the tubes and the solids content of the impregnating and coating solution. Likewise. the temperatures of the heated air circulated through the various compartments and the period which the tubes remain in the compartments may be varied in accordance with the type of impregnating and coating solution employed.

It will be observed from the foregoing that the present invention constitutes an important improvement in the manufacture of coated paper or fibrous tubes used as carriers for yarn and the like during various wet and dry processes. Through the method and means herein disclosed the tubes are automatically and expeditiously caused to be impregnated and coated more thoroughly and evenly without handling. The systematic method explained insures that all of the tubes will be coated completely and uniformly and that the coating material will be treated in such a manner as to render it hard, impervious, insoluble and infusibie.

By use of the improved apparatus a thorough impregnation of the inner fibers of the material of the tubes is effected and finished tubes produced in a continuous operation with economy in time and labor. The improved method of immersing the tubes and slowly draining the solution therefrom provides for an even distribution of the coating material without "runs" or "streaks" appearing on the surface of the tubes or the formation of "rings" at the ends thereof. Moreover, the solvent is removed slowly from the tubes whereby to prevent blistering or otherwise roughing up the applied coat which would cause injury to the delicate filaments of the yarn wound on the tubes.

Furthermore, the apparatus is of simple. compact construction, requiring a minimum of floor area, and is automatic in operation, it being only necessary to load the tubes onto and remove them from the conveyor.

While a preferred form of apparatus is herein shown and described and a preferred method of carrying out the process explained, it is to be understood that modifications may be made in the construction of the apparatus and changes made in the steps of the method without departing from the spirit or scope of the invention.

Therefore, without limiting myself in this respect, I claim:

1. An apparatus for coating articles comprising an endless conduit divided into separate compartments, means travelable in the conduit for conveying groups of articles successively to the several compartments, means for coating the articles, means for circulating air around the articles to evaporate the solvent from the coating solution, and means for eifecting a. gradual rise in the temperature of the circulating air in successive compartments to slowly bake the residual solids of the solution onto the articles.

2. An apparatus for impregnating and coating articles comprising an endless conduit divided into separate compartments, means travelable in the conduit for conveying groups of articles successively to the several compartments, means for preheating the articles, means for impregnating and coating the preheated articles, means for circulating air around the coated articles to evaporate the solvent from the coating solution, and means for effecting a gradual rise in the temperature of the circulating air in successive compartments to slowly bake the residual solids of the solution onto the articles.

3. An apparatus for impregnating and coating articles comprising an endless conduit divided into a plurality of compartments, an endless conveyor within the conduit, means for mounting groups of articles on the conveyor, means for automatically and intermittently operating the conveyor to successively position the groups of articles within the several compartments, and automatically-operated means for successively preheating the articles, immersing them in an impregnating and coating solution, draining the surplus solution from the articles, circulating air around the coated. articles to evaporate the solvent from the solution, and baking the residual solids of the solution onto the articles during the complete travel of the articles through the several compartments of the conduit.

4. An apparatus for impregnating and coating articles of a fibrous nature comprising an endless conduit divided into a number of separate compartments, an endless conveyor within the conduit for conveying groups of articles therethrough, means for intermittently driving the conveyor to successively position the groups of articles within the several compartments, means for circulating heated air through one compartment to heat the articles to extract the normal moisture content and a portion of the air presan impregnating and coating solution to cause the latter to fill the voids and cover the surfaces of the articles, said lastnamed means operating to slowly drain the surplus solution from the articles, means for circulating air within the coating compartment and the remainder of the compartments the solvent from the articles,

varying the temperature of the circulating air in successive compartments, one with respect to another.

5. An apparatus of the type indicated comprising an endless conduit, fixed bane-plates spaced at intervals within the conduit, an endless conveyor travelable within the conduit and adapted to support a plurality of articles, spaced baille-plates on the conveyor, driving means for intermittently advancing the conveyor to aline its baiiie-plates with those in the conduit to divide the latter into a plurality of compartments, means for circulating heated air through one compartment to heat the articles, means in an adjacent compartment for immersing the articles in an impregnating and coating solution and thereafter draining the surplus solution therefrom, means for circulating air through the last-named compartment and the remainder of the compartments of the conduit to evaporate the solvent from the solution on the articles, and means for progressively increasing the temperature of the circulated air in the successive compartments to cause the residual solids to be baked onto the articles.

6. An apparatus of the type indicated com prising an endless conduit, an endless conveyor travelable within the conduit, means for supporting groups of articles on the conveyor, means carried by the conveyor for closing the conduit at points between the groups of articles to form compartments for enclosing the articles, and means for supplying a drying medium at progressively increasing temperatures in successive compartments in the conduit.

7. An apparatus of the type indicated comprising an endless conduit divided into a plurality of open end compartments, an endless conveyor travelable within the conduit, means for supporting groups of articles on the conveyor, means for intermittently traveling the conveyor within the conduit to position the groups of articles within the compartments for treatment, means on the conveyor for closing the ends of the compartments, and means for supplying a drying medium at varying temperatures in succefilve compartments.

8. An apparatus of the type indicated comprising an endless conduit having baiiie-plates, a track extending longitudinally within the condult, an endless conveyor of articulated structure travelable on the track within the conduit, baii'ieplates carried by the conveyor, means on the conveyor for supporting groups of articles between its spaced baflie-plates, and means for intermittently traveling the conveyor along the track to aline its name-plates with those of the conduit to form compartments for containing the difl'erent groups or articles.

9. An apparatus of the type indicated comprising an endless conduit provided with spaced plates dividing its interior into a plurality of compartments, an endless track within the conduit, an endless conveyor within the conduit comprised oi lateral bars hingedly joined together, rollers engageable between the conveyor and track to adapt the conveyor to move therealong, spaced baflie-plates carried by the conveyor, means for intermittently traveling the conveyor along the track to aline its baifle-plates with the baiiie-plates in the conduit to close the compartments, and means for supporting groups of articles on the bars of the conveyor between the baflie-plates.

10. An apparatus of the type indicated comprising an endless conduit, spaced plates within the conduit dividing the latter into compartments, an endless track within the conduit, an endless conveyor travelable on the track, spaced baflle-plates carried by the conveyor, automatically-operated means for intermittently traveling the conveyor along the track to aline its baflie-plates with the plates of the conduit to close the compartments, and frames pendent on the conveyor for supporting groups of tubes between the baiile-plates to adapt them to enter the compartments for progressive treatment therein.

11. An apparatus of the type indicated comprising an endless conduit, fixed plates extending transversely within the conduit to divide the latter into a plurality of compartments, an endless track extending longitudinally within the conduit, an endless conveyor of articulated structure travelable along the track, bathe-plates carried by the conveyor, means for supporting groups of tubes on the conveyor between the baffle-plates, means for intermittently moving the conveyor along the track to aline its baille-plates with the plates in the conduit to provide closed compartments with the groups of tubes positioned in the compartments for treatment, an opening at the side of one compartment through which the groups of tubes may be placed onto the conveyor, and means for closing said opening.

12. An apparatus of the type indicated comprising an endless conduit divided into a plurality of separate compartments, an endless con veyor travelable within the conduit, means for supporting groups of articles on the conveyor, means for driving the conveyor to position the groups of articles within the compartments, means for circulating air through certain of the compartments, and means for effecting uniform distribution of the air during its circulation through the compartments.

13. An apparatus of the type indicated comprising an endless conduit divided into a plurality of separate compartments, an endless conveyor travelable within the conduit, means for supporting groups of articles on the conveyor, means for intermittently driving the conveyor to position the groups of articles within the compartments for treatment, means for supplying air to and exhausting it from certain of the compartments, and means for uniformly distributing the air during its passage through the compartments comprising spaced plates within the compartments between which the articles are positioned, said plates provided with periorations through which the air passes.

14. An apparatus of the type indicated comprising an endless conduit divided into a plurality or separate compartments, an endless conveyor travelable within the conduit, means for supporting groups of articles on the conveyor, means for intermittently traveling the conveyor to position the articles within the diiierent compartments, and means in one of said compartments for immersing the articles to impregnate and coat the same comprising a receptacle for containing a supply of impregnating and coating solution, and means for raising and lowering the receptacle to cause the solution to submerge and drain the articles.

15. An apparatus of the type indicated comprising an endless conduit divided into a plurality of separate compartments, an endless conveyor travelable within the conduit, means for supporting groups of articles on the conveyor, means for intermittently traveling the conveyor to position the groups of articles within the d11- ferent compartments, and means within one compartment for impregnating and coating the articles comprising a tank for containing a supply of coating solution, a second tank surrounding the first tank, means for circulating a cooling medium in the space between the two tanks, and elevating means for raising the tanks to submerge the articles in the coating solution.

16. An apparatus of the type indicated comprising an endless conduit divided into a plurality of separate compartments, means travelable within the conduit for supporting groups of articles to position them in the difierent compartments for treatment, means for circulating heated air around the articles within one compartment, and means for immersing the heated articles in an impregnating and coating solution while positioned in an adjacent compartment comprising a tank for containing a supply of the coating solution, means for maintaining the solution cool, means for circulating the solution through the tank to maintain all parts thereof of uniform viscosity, and means for elevating the tank to submerge the articles in the solution.

17. An apparatus of the type indicated comprising a conduit divided into a plurality of compartments, means travelable within the conduit for supporting groups of articles of fibrous material to position them within the various compartments, means for preheating the articles in one compartment, and means for impregnating and coating the articles with a solution and draining the surplus solution therefrom within an adjacent compartment comprising a tank for containing the solution, means for maintaining the solution cool, means for quickly raising the tank to submerge the heated articles in the cool solution, and means for gradually lowering the tank to permit the surplus solution to drain from the articles directly into the supply of solution in the tank.

18. An apparatus of the type indicated comprising a conduit divided into a plurality of compartments, article-supporting means travelable within the conduit to position the articles for treatment within the various compartments, means for circulating heated air through one compartment to preheat the articles, and means for impregnating and coating the articles and draining the surplus solution therefrom in an adjacent compartment comprising a water-jacketed tank for containing a supply of the solution, means for circulating water through the jacket to maintain the solution cool. means for circulating thesolution in the tank to maintain the temperature and viscosity thereof uniform, means for elevating the tank to submerge the articles in the solution, means for slowly lowering the tank to permit the surplus solution on the articles to drain directly into the so lution in the tank, and means for circulating air through the impregnating-and-coating compartment and around the articles during the draining operation.

19. An apparatus of the type indicated comprising an endless conduit divided into a plurality of separate compartments, means movable within the conduit for supporting and conveying groups of articles to the various compartments, means for circulating heated air through one compartment to preheat the articles, means for impregnating and coating the articles with a resinous solution and draining the surplus solution therefrom in an adjacent compartment, means for circulating air around the articles in the next compartment to evaporate the solvent from the applied solution, means for circulating air at a higher temperature in the next compartment to further evaporate the solvent and cause the solution to congeal on the articles, and means for circulating air at still higher temperature in one or more compartments to bake the residual solids firmly in place on the articles.

20. An apparatus of the type indicated comprising an endless conduit of rectangular configuration divided into a plurality oi compartments, said conduit having two of its sides extending horizontally and the other two sides vertically, guiding means within the conduit, an endless conveyor movable along the guiding means, means for suspending the articles on the conveyor, a receptacle for containing a supply of coating solution arranged beneath one or the compartments, and means for moving the receptacle into the compartment to submerge the articles in the solution.

21. An apparatus of the type indicated comprising a conduit divided into a plurality of compartments, means within the conduit for supporting and conveying groups of articles into the several compartments for treatment by drying and baking, means for actuating the articleconveying means, means for supplying a drying medium at progressively increasing temperatures in successive compartments in the conduit, and a time-control unit for intermittently energizing the conveyor-actuating means.

22. An apparatus of the type indicated comprising an endless conduit divided into a pinrality of separate compartments, an endless conveyor for supporting groups of articles and movable to transport them into the compartments for treatment, movable means for immersing the articles in an impregnating and coating solution while in one compartment, means for intermittently actuating the conveyor. means for intermittently operating the article-immersing means, and means for synchronizing the movement of the conveyor and article-immersing means.

23. An apparatus of the type indicated comprising an endless conduit divided into a plurality of separate compartments, an endless conveyor for supporting groups of articles and transporting them into the compartments for treatment, an electric motor for driving the conveyor,

a movable tank for containing a supply of coating solution, means for moving the tank into position to immerse the articles in the solution, a time-control unit for regulating the periods of operation 0! the tank-moving means, and means operated by the movement or the tank for energizing and deenergizing the conveyor-driving motor to cause the latter to intermittently move the conveyor within the conduit to successively present diii'erent groups of the articles to the immersing tank.

24. An apparatus 0! the type indicated comprising an endless conduit, an endless conveyor travelable within the conduit, and means for supporting articles on the conveyor comprising carriers, means for mounting the articles on the carriers, and means for removably attaching the carriers to the conveyor.

25. An apparatus 01' the type indicated comprising an endless conduit, an endless conveyor travelable within the conduit, and means for supporting articles on the conveyor comprising carriers, means for removably attaching the carriers to the conveyor. and holders on the carriers for engaging the opposite ends of the articles.

26. An apparatus of the type indicated comprising an endless conduit, tube-conveying mean travelable within the conduit, frame-members consisting of opposite parallel bars, tube-holders carried by the bars, said holders having means engageable with the ends of the tubes, and means for removably attaching the flame-members to the tube-conveying means.

27. An apparatus of the type indicated comprising an endless conduit, tube-conveying means travelable within the conduit, frame-members consisting of opposite parallel bars, means connecting the ends of the bars, means for supporting tubes in the frame-members comprising holders on the bars, means on the holders for engaging the inner rims at the ends 0! the tubes at spaced points, means for drawing the bars of the name-members together to cause the holding means to eng e the tubes, and means for removably attaching the frame-members to the tube-conveying means.

28. An apparatus of the type indicated comprising an endless conduit, conveying means travelable within the conduit, frame-members, means for removably attaching the frame-mombers to the conveying means, and means for supporting tubes on the frame-members comprising holders arranged on opposite sides of the frames, said holders provided with relatively narrow arms for engaging the inner rims at the ends of the tubes at spaced points therearound.

29. An apparatus of the type indicated comprising an endless conduit, a conveyor travelabl within the conduit, carriers detachably mounted on the conveyor, and means for mounting tubes on the carriers comprising opposite holders, said holders constructed from wire and formed with narrow inclined arms engageable with the inner rims at the ends of the tubes at spaced points therearound, and means for attaching the tube-holders to the carriers.

30. An apparatus of the type indicated comprising an endless conduit, an endless conveyor travelabie within the conduit, means for supporting tubes on the conveyor comprising tubeholders having inclined arms engageable with the inner rims at the ends 01' the tubes at spaced points therearound, means for drawing the tubeholders toward each other to support the tubes therebetween, and means for removably attaching the tube-holders to the conveyor.

31. An apparatus for coating articles comprising an endless conduit, an endless conveyor for supporting groups of articles in the conduit, means in the conduit for preheating the articles, a tank containing a supply of coating solution, means for relatively moving the tank and conveyor for immersing the preheated articles in the solution, means for intermittently actuating the conveyor to advance the articles through the conduit, means for circulating air around the coated articles in the conduit, and means tor effecting a gradual rise in the temperature of the circulating air at different points along the conduit to bake the solution on the articles.

32. An apparatus for coating articles comprising an endless conduit, an endless conveyor travelable within the conduit, means for supporting articles on the conveyor comprising carriers, means for removably attaching the carriers to the conveyor, means in the conduit for preheating the articles, means for impregnating and coating the preheated articles, means for circulating air around the coated articles to evaporate solvent from the coating solution, and means for efiecting a gradual rise in the temperature of the circulating air at predetermined points along the conduit to slowly bake the residual solids of the solution on the articles.

EVERETT C. ATWELL.

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