US2282899A - Apparatus for cooling freshly coated articles - Google Patents

Description

My -12,-1-942. I. JSNADER E'm- 2, 99

'APPAnA'rus. FOR COOLING masuu comm ARTIcLEs Original Filed Oct. 30, 1937 4 ShetS-Shet 1 May-12,. 1942. l. J. SNADER ET AL APPARATUS FOR c'ooLme-r'nnsnw comm An'nxjcms driginal Filed Oct. 30, 19%? 4 Sheets-Sheet 2 y 1942 l. J. SNADER EIAL 2,282,899

APPARATUS FOR QOOLING' FRESHLY COATED ARTICLES Origipal Filed Oct. so, 1937 4 Sheets- Sheet a 1..1. SNADER ETAL 2,282,899 APPARATUS FOR COOLING Famsnw comm: narrows original Filedoot. so, 1937 4 Sheets-Sheet 4 or water-repellent mixable substances.

Patented May 12, 1942.

UNITED STATES APPARATUS FOR COOLING FRESHLY COATED ARTICLES Ira J. Snader and James F. Earp, Jr., Detroit, Mich., assignors to The American Paper Bottle Company, Toledo, Ohio, a corporation of Ohio Claims.

The present invention relates to apparatus for cooling freshly coated articles and particularly to apparatus for cooling and solidifying coatings applied in molten ccndltion to articles such as paper containers.

Paper containers of numerous types have been heretofore widely made use of in the packaging and distribution of numerous commodities, principally solid products, being attractive in appearance, light in weight, and comparatively inexpensive. But little dlfilculty is met with in designing a suitable container of paper for the storage and transportation of almost any solid commodity, but substantially greater diiilculty is realized in designing a paper container suitable for the storage, transportation and dispensing of liquids, largely by reason of the fact that the fibrous paper readily absorbs liquids and loses a large proportion of its strength after becoming wet. Hence it is necessary and customary to coat the surfaces, at least the inner surfaces, of a paper container which is primarily intended to receive liquids, with a layer of. a substance .which is impervious to the penetration of liquids,

it being the function of such substance to prevent contact of the liquid contents of thecontainer and the fibers of the paper wall. A material commonly chosen for the coating of, pa-

per containers comprises parafiin and this this used either by itself or admixed with other waxes Such coatings are customarily applied while in molten condition'and as soon as the surfaces of the container or other object to be coated are completely covered over by the molten coating substance,

coating apparatus and permitted to cool; As it cools the coating substance cools likewisev and soon is transformed from a liquid to a solid substance closely adherent to the walls of the coated article and, as a matter of fact, imparting increased stifiness theretoJ/ It is of particular advantage to employ a coating substance of this character where paper containers are to be coated since the coating substance substantially reinforces and stiflensthe paper walls and renders them more definitey selfsupporting when subjected to the internal pressure of the contained liquid. Advantageously the freshly coated article is subjected to the action of cooling media for the purpose of effecting the more rapid setting or hardening of the coating material. It is particularly helpfulto' subject freshly coated containers to the action of cooling media where the result "is to effect the increase in production or containers upon a complete container fabricating machine. Thus, ma-. chines for receiving folded paper blanks and opening, glueing, coating, charging, sealingand stapling of the original blanks are now in wide- PATENT OFFICE! 5 ation of that one of its units which operates most slowly. Where freshly coated containers are merely allowed tostand in the air until the coating substance has hardened and set, the rate of production of a machine of this character would be materially lessened. It is proposed by the present invention to provide an apparatus particularly suitable for use in conjunction with a complete automatic machine for the fabricating, coating, charging and sealing of paper conl5 tainers, whereby the rate of cooling of the con- 7 tainer is greatly expedited, but the invention is likewise of value when employed in chilling and solidifying coatings of articles other than paper -containers andeven" when forming no part of a complete automaticmachine of the type described. s

The cooling means contemplated by the, invention includes at least 'two cooling media and that portion of the container which tends to retain its heat longest, which portion is generally the bottom, is subjected to the action of a cooling medium of relatively high heat conductivity where,-

as that portion, or those 'portions, of the contain.. er which is or are of lighter section is subjected to the action of a cooling medium of lower heat conductivity. For instance in the case of a tubular container having a multi-ply bottom, the heavier bottom portion of the freshly coated container is immersed in a liquid bath cooled to a low temperature whereas the thinner portions of thearticle is removed from the vicinity of the the container wall are sufliciently cooled and the coating material thereon hardened, by the simple application thereto of a current of cooled air-or other gas. The cooling of the bottom of 40 the freshly coated container, and of the side walls, is effected simultaneously by the two media so that the cooling of the entire container and.

the hardening of its coating layer is effected in a minimum of time, a consideration of much .15 importance in many instances, particularly when the cocling'apparatus is used in conjunction with an automatic machine 'of the type above briefly referred to,

By way of example, one embodiment of the cooling apparatus is illustrated in the accompanying drawings, but it will be appreciated by those skilled in the art that the design and arrangement of numerous elements of the invention may be substantially modified without departure therefrom, particularly in adapting the invention to the cooling of containers and other articles of different shapes and sizes. r

In the drawings:

.. Figure 1 is a side elevationoi the cooling unit 0 in the form in which it appears as one element of a complete automatic machine for squaring out, glueing, coating, charging, cooling and sealing paper containers. In conjunction with such machine the present cooling apparatus is particularly useful;

Figure 2 is a top plan view of the apparatus shown in Figure 1;

Figure 3 is a longitudinal vertical central section through the cooling apparatus;

Figure 4 is a section on line 44 of Figure 3;'

Figure 5 is a section on line 55 of Figure 3;

Figure 6 is a rather diagrammatic view showing the refrigerant cooling circuit of the cooling means;

Figure 7 is a side view of certain portions of the cooling means;

Figure 8 is an end view of these same portions, partly broken away; and

Figure 9 is a perspective view, partly broken away, of a paper container of a shape and type which the cooling unit shown is well adapted to receive and act upon.

As has been previously explained, cooling units for chilling and solidifying the freshly applied coatings of various kinds and shapes of articles are contemplated by the present invention. The cooling unit actually illustrated, however, has been designed particularly to receive and act upon .paper containers of the type shown in Figure 9. That container is fabricated of relatively thin stiff paper of good quality and comprises a body portion having four rectangular panels a, a foldable top portion b and a closure or bottom 0 at its lower end, the container being coated with the selected material while in the stage of completion in which it is shown in Figure 9, the bottom 0 having been fully formed but the upper end closure being open or unfolded. The body and foldable top of the container are formed of a single thickness of paper but the bottom is built up of several plies or thicknesses, preferably three, and is therefore of much heavier section than either the side wall or top of the container. The apparatus contemplated by the invention is so designed that the different capacities of the bottom and sides of the container to store heat are fully taken into account. and compensated for.

The method of and means for applying a molten coating substance to the container comprises noportion of the present invention and will not be described in detail. It may be stated, however, that a container of the type shown, and which is intended for use in the packaging of liquids such as milk, shall be actually immersed or dipped in a bath of molten coating material so that it is fully coated both inside and out just prior to its introduction into -the cooling unit. A suitable apparatus for coating-containers of the type illustrated in the manner just described is fully disclosed in our copending application, Serial No. 172,025, filed 'October 30, 1937, of which the present application is a division. After the container is immersed in the molten coating material and all of its surface areas fully exposed to contact with such material, it is withdrawn, drained, and then erected or positioned as shown in Figure 9. Certain of the molten material upon the walls will tend to flow downwardly and a portion of the coating material upon the inner surfaces of tlce container will flow downwardly and be collected upon the upper surface of the bottom c. With certain types of containers small additional amounts of coating substance may be introduced o as to form a layer pointed out, for a relatively short distance.

of coating material of the desired thickness over the surface of the bottom 0, a rather thick coating being highly desirable here in order to eliminate the possibility of leakage. Naturally, however, the coated bottom, comprising as it does several plies of paper and a substantial layer of molten material superposed thereon, contains a considerably larger number of heat units than does any corresponding area of a side wall and tends to cool off much more slowly.

The cooling unit comprises the insulated box or housing generally indicated at I0, the top portion ll of which is attached by hingesl2 tothe main orlower portion l3, apertures H and IS in the ends of the housing, and formed partially in the top and partially in the main or lower portion l3, being provided for the introduction and discharge of containers. The several instrumentalities for the cooling or chilling of the coated containers are enclosed within this casing or housing. Projecting through the opening I4 is a trackway l6 over which the containers to be subjected to cooling are'slid from a point without the housing to a point within the housing, this trackway being preferably heated for reasons fully set forth in our copending application previously referred to.

A conveyor is made use of in association with the trackway l6 and the cooling instrumentalities, for moving containers over the trackway l6 into the housing In and horizontally along a predetermined path from the inlet opening I4 to and out of the outlet opening IS, the successive positions of a container so moving through the housing being indicated at P, P' P P and on up to P. The details .of the conveyor may be varied widely to suit conditions. That which is employed in association with the cooling mechanism shown includes endless chains l1 and 18 disposed in a horizontal plane and extending longitudinally of the housing 10, the two chains having parallel reaches on opposite sides of the path of movement of the containers and each chain being provided with a large number of equidistantly spaced pusher arms, these arms being generally indicated at IT and I8, respectively. In the operation of the device a pair of pusher arms engages the rear wall of each of the containers shown and the chains are advanced simultaneously to cause each container to be moved through the housing at uniform speed.

In Figure 3 of the drawings no attempt is made to illustrate the conveyor chains but the pusher arms II are illustrated to show how each container is engaged by one of such arms.

The trackway Ii extends through the entrance aperture ll of housing", as has previously been neath this portion of the trackway is a drip pan IQ for collecting any paraflln or other coating substance which may drop from the containers while they are passing along the heated trackway, this drip pan sloping downwardly and discharging into the drip pan 20 by means of which it is collected in readiness to be returned to the coating unit by a conduit or channel which is not illustrated. In Figure 3 of the drawings the containers indicated at P, P and P"' are shown to be resting fairly upon the trackway l6 and the container P still engaging the trackway at its end but about to be shoved over the terminal end of the trackway. The remaining containers have passed from the trackway and have their lower ends immersed in a body of cooling liquid indi- 22 is has upwardly and inwardly turned flanges 22'.

means of a shaft 34 with a cated at. 2f which liquid, preferably water, is containedin a longitudinally extending pan 22. Pan relatively long and narrow, is shallow, and

The liquid contained in this pan is cooledto a low temperature artificially .and is of'relatively high heat conductivity so that the temperature of each container bottom, which is of multi-ply construction and also heavily coated with coating material, is rapidly reduced. The liquid body 2| is of such length that by the time that V a container has reached the position P both the multi-ply paper bottom and the paraflin or other coatings above and below the same have been thoroughly chilled and the coating material rendered quite hard. The container? has, as a matter of fact, been lifted out of the liquid body,

having been moved up inclined guides 23' so as to pass over a header 23 which forms one end of the liquid pan. A similar header 24 comprises the other end of this pan-and these headers likewise constitute the pan supports, being themselves supported upon brackets or rests 25- and'28 rigidly supported within the housing It. Further advance of a container from position P will cause it to move through aperture l5 and hence be discharged from the apparatus.

It will be observed that header 23 has formed therein a longitudinally extending aperture 28 and that header 24 has likewise formed therein a longitudinally extending aperture 29. These respective bores or apertures are in communication, respectively, with the ends of a plurality of pipes or tubes 30 which extend longitudinally of pan 22 and are positioned approximately at the bottom of the pan. Cooling fluid is passed through the relatively small tubes 30 from one header to the other, by means to be hereinafter more particularly described, and the body of liquid in the pan thereby maintained at a low temperature. When the liquid is water, its temperature is maintained slightly above its freezing temperature so that heat stored in the container bottoms and the coating material upon the container bottoms is rapidly transferred to the much cooler liquid.

During the time that eachcontainer is moving through the housing that portion thereof which lies above the level of the liquid in pan 221s subjected to the action of a cooling gas, preferably air cooled to a low temperature, all of the exterior wall surfaces beingactedupon by the cool gaseous streams, the eifect of which'is tochill and harden the coating material upon the upper portions of the container so that, when a container reaches the position indicated at P, the

. coating material covering its entireupper part,

-3 is directed upwardly between baille 39 and the adjacent vertical side wall of the housing Ii, passes over a plurality of horizontally extending ducts 40 equipped with heat collecting flns 4|, and thence upwardly toward thetop of the housing as further indicated by the arrows of both Fi ures 4 and 5.

r A cooling fluid, which maybe either a liquid or a gas, is circulated through tubes 40 by means to be hereinafter described and the air passing past these tubes is cooled, by contact therewith and with the heat cooling fins 4|. Toward the top of the housing the stream 'of upgoing air meets a plurality of inclined baifling plates 42,

43 and 44, rigidly supported in the positions shown inFigure 5, which serve to,direct the air inwardly and upwardly toward the series of con..

tainers so that the adjacent longitudinally extending .side surfaces of these containers are directly subje ted to the action of impinging air streams and the, transversely extending forward and rear side walls of the container are likewise subjected to the action of streams of air passing between the containers.

A certain amount of the upfiowing air stream will pass the lower or, leading edge of the baflie plate 44 and pass along the lower surface of the top of the housing to containers where it will meet and be downwardly deflected by the curved baflie 45 into the interiors of the several containers, thus causing rapid circulation of air within these interiors and direct cooling of the inner coating of the coating material. Air issuing from the containers as well as air passing over the top of and between the containers will strike the downwardly inclined surface of the top of.the housby theseries of baflies 46,

41 and 48, thereby being directed against those not previously directly contacted by rapidly flowtinct and of course the streams will be constantly changing. because of the advancing movement gas may be employed. Finally,

likewise containing a circulating .elther gas or liquid, the air passing as well as 'the coating 'r'naterialupon its bottom,

has been thoroughly chilled and hardened.

A blower or fan is indicated at '33, this fan being mounted upon the bottom of the housing and the rotor of the fan'being connected by power source such as the electric motor 35 which is positioned without the housingand supported upon a bracket 34. The blower 33 is of the type which receives or draws in air axially of the rotor and at both ends of the rotor, arrows 31 indicating the direction of air inflow into the arrows 8, Figure 5,

end of the blower.

The air thus drawn in is discharged transversely of the blower axis and the 'indicate the direction of flow of theair dia- 'just described, therefore, a body ing air streams. The demarcation between the various streams of air flowing over into and around the containers will not be' sharp or disof the containers. Nevertheless all areas of the container above the level of the liquid in pan 22 will be subjected 'to flowing streams of cool turbulent air. In lieu of air, any other cooled downwardly through a-sec'ond series of tubes 50, having heat collecting flns 5|, the tubes lying to the left of the baife 39 (Figure 5),- these tubes cooling fluid, flnally to the By the means of cooling gas may be continuously circulated within the housing and caused by battling devices to flow past all exposed, surfaces of the series of containers thereins e While the'housing is not gas-tight, having the fan or blower for recirculation.

0 be ut little cooled air escaping in the ordinary operation .of the unit and naturally any air es.--'

caping will be automatically replaced by inflow from the outside. The numeral .53 (Figure 5) indicatesasmall tube the discharge end of which overlies the liquid pan :2. ;-.1'-t through this" tube that a regulated flowv of lfquid is passed into the liquid pan to replace that which is carried out of the containers passing to the outletopenins II. The

a point above the line of sides of the containers the air is drawn apertures l4 and 45 at its ends, there will pan upon the bottoms of the nected to the valves flow of liquid into th pan may be regulated by a needle valve and any excess liquid supplied will pass over the header 23 and fall onto a drip pan 54, by which it is conducted to a point of disposal.

The means for circulating a cooled fluid through the'conduits previously mentioned is diagrammatically illustrated in Figure 6. In this figure a main supply line is indicated at 60, this main leading from any suitable source of cooling fluid. While the cooling fluid may be either in gaseous or liquid form, the apparatus which is illustrated is one which had been primarily designed to be "used with brine as a cooling medium, brine being introduced into the system from a suitable source through the supply main 60 at a temperature which may vary between zero and 20 F. From main 60 a branch line 6! leads to the system or battery of air cooling tubes 40 and, from this series of tubes, into tubular casing 63, thence into conduits B4, and finally to discharge main 65 by which it is conducted to a brine cooling, and recirculating mechanism which is not illustrated. Asecond branch line leading from main 60 is indicated at 66, this branch leading to header 24 which header, as has been previously explained, communicates with a second header 23 f by means of a plurality'of 'tubes 30, only one of which is shown in Figure 6. From header 23 the brine is conducted through conduit 68 to a cylindrical housing 69 and is thence conducted through conduit 10 to the brine return main 65. The housings 63 and 69 previously referred to contain thermostatic elements H and 12, respectively, indicated in dotted lines, which elements are preferably of the fluid expansion type and .either mechanically or by fluid pressure means are operatively connected to two control valves 14 and 15, respectively, valve 14 controlling the flow of cooling liquid through branch 6| to the air cooling tubes 40 and valve 15 controlling the flow of brine through conduit 66 to the liquid cooling tubes 30.

It will be observed that the thermostatic elements 1| and "are both disposed in the liquid circulating system so that each is encircled by a body of brine which has already performed its cooling functions. Hence it is clear that valves 14 and 15 are controlled in accordance with variations in temperature of-the two outflowing brine streams. The system is entirely automatic in operation and valves 14 and 15 are of course independently regulated so that the body of water in pan 22 may be subjected to the action of additional or reduced amounts of cooling brine, likewise the air cooling coils 40, or vice versa. It will be understood that no novelty is claimed for the are subjected to the action of cooling media havof the containers are more difficult to cool than other portions, all parts thereof are brought to completely cooled condition practically simultaneously. It is apparent that the cooling apparatus may be varied in detail to a substantial extent without modification of function or result, particularly in adapting the principle of the invention to the chilling of coatings of articles which vary in size and shape from the containers shown. Any suitable gas may be circulated in the housing, rather than air, and likewise the cooling fluid may be a liquid or a gas, although preferably a liquid where a fluid circulation system of the type specifically disclosed is utilized.

' Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. Apparatus for cooling freshly coated paper containers including a chamber having spaced apertures through which containers may be in-' for a"-' chilled liquid underlying the conveyor to receive the lower ends of containers being advanced by said conveyor, and means disposed in said pan and extending longitudinally thereof beneath the normal liquid level, said means being adapted to slidably support the bottoms of containers which sink through the liquid.

2. The combination set forth in claim 1 in which the said means submerged in the liquid retained within said pan comprises a plurality of parallel tubes adapted to transmit a refrigerant and to serve to support containers the bottoms of which descend in the liquid belowa predetermined level.

3. Apparatus for cooling freshly coated paper containers comprising a chamber having spaced details of construction of the thermostat means.

for controlling the operation of the valves I4 and I5 and that any suitable thermostatic devices available may be employed. Preferably, how-' ever,'the thermostats are of the gas expansion type and the variations in gas pressure within thermostatic elements H and 12 cause the operation of bellows devices within the housings diagrammatically illustrated at 11 and 18, respecwhich bellows devices are directly contively,

through valve stems 19 and 8..

apertures through which containers may be introduced and discharged, respectively, a conveyor for moving containers along a predetermined path from thecontainer introduction aperture to the container discharge aperture, said conveyor including a plurality of spaced pushers for advancing containers without restraining them against vertical movement, and a pan adapted to contain a liquid cooling medium located in said chamber, said pan underlying the conveyor so that containers being advanced by said pushers will have their lower ends immersed in the liquid retained in said pan.

4. The combination set forth in claim 3 in which mechanism is provided for directing 9. current of chilled air over the surfaces of the containers the. lower ends of which are immersed in the liquid in the pan.

5. The combination set forth in claim 3 in which an air current-directing vane is positioned on each side of the conveyor and extends parallel thereto, and means is provided for circulating a current of chilled air within -the chamber so as to pass the said vanes and be guided thereby, and- IRA J. SNADER.

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