US3390465A - Drier - Google Patents

Description

W. G. WISE July 2, 1968 DRIER 3 2 Sheets-Sheet 1 Filed June 13, 1966 EXHAUST III] II II IIIJI INVENT OR. WALTER G. WISE W. G. WISE July 2, 1968 DRIER 2 Sheets$heet 2 Filed June 15, 1966 INVENTOR. W41 TER 6. Wm:

l/farmsgs United States Patent 3,390,4a55 DRIER Walter G. Wise, P.0. Box 27066, Indianapolis, Ind. 46227 Filed June 13, 1966, Ser. No. 557,053 13 Claims. (Cl. 3423) ABSTRACT 0F THE DISQLOSURE The present invention relates to a method and apparatus for drying printing inks, lacquer, enamel, paint, varnish and other marking and coating material which has been printed or placed on paper, aluminum roofing, plastic ce lophane, etc.

It is present practice in the printing industry to dry the ink on a printed Web by burning the volatile portions of the ink. Thus the web is printed with the ink and is then subjected to heat sufiicient to evaporate and burn the volatile components of the ink. The drying of the ink must be complete prior to the winding of the web on the rewind roller or else the ink may be smudged. It has been found that such conventional printing and drying apparatus are capable of a web feeding speed of only approximately 400 feet per minute where multicolor heat setting inks are used. One limiting factor on the speed of the web is the fact that at higher speeds the combustion of the volatile components cannot be confined to the furnace and there is, therefore, a tire hazard.

Consequently, one object of the present invention is to provide a method and apparatus for drying printing inks and the like which permits a web speed much higher than 400 feet per minute with resulting savings in the cost of printing.

Another object of the invention is to provide a method and apparatus for drying printing inks and the like which is safer than presently existing methods and apparatus.

A further object of the invention is to provide a method and apparatus for drying printing inks and the like on a web which reduces damage to the web and thus reduces scrap.

Still another object of this invention is to provide a method and apparatus for drying printing inks and the like which reduces initial cost of a drier to from to 35% of the cost of conventional driers, this cost reduction being possible because of the smaller possible size of the drier and the relative simplicity thereof.

The drying of printing inks is only one example of a general problem. Thus the present invention relates not only to the drying of printing inks but also to drying of paints, lacquers, enamels, and water based coats which are applied by non-electrostatic or electrostatic spraying, or by roller coaters or the like. Thus, this general problem is the fact that many marking or coating procedures are only as good as the weakest link which is the drying process. Because the speed of this drying process is limited, the speed of the entire coating or marking process is limited. Thus a further object of the present invention is to provide a method and apparatus for drying coated or marked materials in a much more rapid fashion than existing methods and apparatus, thus making possible other improvements speeding up marking and coating procedures.

Still another object of the invention is to provide method and apparatus for drying coated or marked materials at drying temperatures varying through broad ranges, for example, 200" F. to 1800 F. without heating the web or sheets to a temperature that causes scrap. In accordance with one example of the present invention, the flame from a line gas burner may be combined with a small volume of extremely high velocity controlled directed air resulting in rapid drying of coating or marking. This combination makes possible removal of volatile oils, solvents or water without appreciably increasing the temperature of the material that has been coated or marked. It has been possible by the use of this invention to dry printing inks which have been placed on polyethylene without raising the temperature of the polyethylene web above F. This is particularly impressive because the inks include solvents (water, alcohol, glycol ethers and the like) with boiling points as high as to 250 F. and the polyethylene clouds or opacifies at 230 F.

A further application or advantage of the present invention is the drying of multicolored lithographic inks which have been placed on polyethylene coated carton paper board. Such lithographic inks contain no solvents but instead petroleum oils, varnish and traces of metallics which can only be dried at high temperatures between approximately 300 and 600 F. Such high temperatures would destroy the polyethylene coated board which, in fact, is destroyed at 240 In the past, therefore, it has been impossible to place the beautiful colored pictures such as appear in magazines on, for example, milk cartons because the ink could not be dried. The present invention makes possible such pictures on milk cartons because the temperature of the polyethylene can remain low and the ink can still be dried.

There are presently available perhaps three drying procedures for accomplishing drying of coating or marking. Those procedures are: (1) use of a flame to burn or incinerate solvents or oils from the coating and marking material, (2) use of a radiant heating element to burn or incinerate solvents or oils from the coating and marking material, (3) use of a convection type drying chamber. As they are presently known, the first two above methods produce high residual heat. In other words, when it is desired to shut down a press, frequently the web or material being coated will be scorched or burned because there is no good way to get rid of the stored heat or residual heat. Consequently, another object of this invention is to provide method and apparatus for drying without high residual heat. By accomplishing this object alone in one conventional printing press arrangement, this invention saves $60 to $75 per day in scrap prevention. The third above mentioned method as presently known cannot be accurately controlled because of the difficulty of moving large quantities of heated air. It is, therefore, another object of this invention to provide method and apparatus for drying which can be easily controlled.

Still a further object of the invention is to provide a method and apparatus for evaporating moisture or water from material prior to printing, marking or processing.

Another object of this invention is to provide a drier method and apparatus capable of thoroughly mixing air and products of combustion.

A further object of this invention is to provide a method and apparatus for drying printing inks whereby use of oxides to absorb solvents in inks is avoided. Such oxides frequently result in dulled, dusty and hazy images and in sealing together of parts of the printed surfaces. Also, such oxides are extremely abrasive and result in high maintenance costs for the printing presses.

Related objects and advantages will become apparent as the description proceeds.

One embodiment of the method of the present inven tion might include the drying of printing ink and the like after such ink has been applied to a material which comprises the steps of directing a flow of heated gaseous fluid at the material, causing relative movement between the material and the flow whereby the flow wipes across the material and removes volatile portions of the ink from the material, said gaseous fluid including a sufflcient amount of excess oxygen or air to prevent combustion of the volatile portions.

One embodiment of the apparatus of the present invention might include a housing with a gas burner mounted therein. Adjacent to the gas burned is mounted a fresh air nozzle which is arranged to direct a jet of fresh air across the path of the products of combustion from the gas burner. The fresh air nozzle is also aimed at the printed material to be dried so that the mixture of the products of combustion and the fresh air wipe the surface of the material and dry it.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims.

FIG. 1 is a top plan view of an apparatus for drying printing inks and the like embodying the present invention.

FIG. 2 is a vertical section taken along the line 2-2 of FIG. 1 in the direction of the arrows.

FIG. 3 is a vertical section taken along the line 33 of FIG. 1 in the direction of the arrows.

FIG. 4 is an enlarged view similar to FIG. 2 showing in detail one of the burners and associated fresh air nozzle forming a part of the structure.

FIG. 5 is a section similar to FIG. 2 of an alternative embodiment of this invention.

FIG. 6 is a section similar to FIG. 2 of a further al ternative embodiment of this invention.

FIG. 7 is a section similar but enlarged relative to FIG. 4 of still another alternative embodiment of this invention.

For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawing and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.

Referring now more particularly to the drawings, there is illustrated a housing 10 within which is mounted a pair of burners 11. It should be understood that the present device is operable with only a single one of the burners 11 although two or more such burners are also usable and are desirable in the situation where greater drying capability is desired. As shown by the representative burner in FIG. 4, the burner 11 comprises a conduit 16 having formed therein an elongated indentation 12 of U-shaped cross section. Orifices 15 lead from the inside of the conduit 16 into the indentation 12. The conduits 16 of each burner are fed with a suitable gas air mixture through the conduits 17 into which the venturi 2t) exhausts.

A suitable blower 21 is provided for supplying fresh air through the duct 22 to the venturi and also for supplying fresh air through the duct 25 into a longitudinally extending duct 26. The duct 26 communicates with the fresh air nozzles 27, both of which extend completely across the chamber 28 inside the housing 10.

The complete assembly also includes a suitable take-up reel 30 which draws the web of paper 31 through the housing 10 and across an idler roller 32. It will be noted that the housing 10 is formed with elongated slots or openings 35 at its opposite ends through which the web 31 is moved. The housing 10 is closed on all sides except for the exhaust opening 36. In some embodiments of the invention, the exhaust opening is provided with an exhaust fan for rapidly moving the products of combustion and the fresh air from the fresh air nozzles 27 away from the housing. In other embodiments of the invention, however no exhaust fan is necessary and the hot air mixture from the burners 11 and fresh air nozzles 27 is removed from the housing by gravity.

Referring to FIG. 3, suitable means 40 and 41 are provided for lighting the gas air mixture as it leaves the orifices or ports 15 and for sensing the presence of flame in the indentation 12. The means 40 and 41 may be, for example, a 4 EN fi-mechanism produced by Pyronics, Inc, of Cleveland, Ohio. This mechanism includes a spark plug and a flame rod. When the mechanism is properly conditioned, the spark plug sparks until such time as the flame rod senses the presence of a flame. The venturi 20 may be, for example, manufactured by Western Products, Inc, of New Castle, Ind, and may be a standard two inch iron pipe proportional mixer. The blower 21 may be a suitable blower capable of producing 700 c.f.m. at 1.5 pounds per square inch pressure gauge. The relatively small size of the present device is illustrated by the fact that an actual embodiment thereof constructed according to the drawing is only three feet by four feet by one foot.

Suitable means are provided for controlling the rate of flow of the fresh air into the fresh air nozzles 27 and for also controlling the rate of flow of gas into the venturi 20. The valve 50 in the conduit 25 controls the rate of flow of fresh air into the fresh air nozzles, while the valve 51 controls the rate of flow of gas into the venturi One of the most important features of the present invention is the fact that the volatile solvent within the ink are dried not by burning thereof but instead by evaporating. Referring to FIG. 4, it can be seen that the flame 69 is directed at the web 31 but does not burn as far downwardly as the web 31. In one embodiment of the invention the flame burns, for example, approximately an inch away from the lower surface of the burner 11 while the web of material 31 is positioned between one and four inches away from the burner 11. Also, the output of the fresh air nozzle 27 is aimed at the material 31 but is also directed across the path of the products of con1- bustion 60 from the burner 11. One means of adjusting the heat delivered to the web 31 is by adjusting the distance between the web 31 and the apparatus 11 and 27 since the fresh air 61 is hotter closer to the slot exit 62 and is cooler away from exit 62.

As illustrated in FIG. 4, the fresh air 61 exiting from the fresh air nozzle 17 diverges slightly in its movement from the slot exit 62 of the fresh air nozzle to the surface of the web 31. In one embodiment of the invention this divergence of the fresh air flow 61 is approximately seven degrees. In order to prevent combustion of the volatile components in the ink being dried, a sufficient amount of fresh air must be supplied through the fresh air nozzle 27 to produce a situation in which there is excess air for combustion at the surface of the material 31. It has been found that the present invention operates safely and prevents combustion if percent of excess air is provided through the fresh air nozzle 27. In other words, sufficient fresh air is provided through the nozzle 27 so that there is 100 percent more fresh air in the resulting mixture of fresh air and products of combustion which moves against the web 31 than in a mixture which would cause combustion of the volatile portions removed from the ink, said last mentioned mixture being the mixture with the greatest amount of air that would cause such combustion. The present invention provides a mixture of fresh air and products of combustion at the surface of the material 31, which mixture moves across the material 31 so rapidly that there is no possibility of igniting the volatile combustible components in the ink. There is in effect an impingement and wiping of the surface 31 with air.

The width 62 (FIG. 4) of the slab 61 of air is approximately one-half inch where the distance from the nozzle is measured in the direction of flow of the air and said distance is two inches. In such a situation movement of the material 31 at 800 feet per minute causes the slab 61 of air from a single burner nozzle combination to blow against the material 21 for of a second.

The controls 50 and 51 for the amount of fresh air provided and the amount of gas provided are adjusted depending upon the result desired. For example, if ink containing methyl solsosol solvent is to be dried, a temperature of 260 F. is required in order to get the solvent out of the ink. Thus the controls 50 and 51 would have to be set to provide a sufficient amount of products of combustion in the products-of-combustion-fresheair mixture to have the temperature at the surface of the material 31 at or above 260 F. Assuming further that the material or web carrying the ink is polyvinyl with a lustered surface, the temperature at the lustered surface of the material cannot rise above 200 F. or else the material will lose its luster or become translucent. It has been found that proper settings of the valves 50 and 51 according to the above requirements produce a web temperature of 180 R, an exhaust mixture temperature at the wiped surface of 1000 F. Even through the temperature of the moving mixture at the surface 31 is 1000 F., still the web does not increase in temperature beyond 180 F. Thus, even though the solvents are thoroughly volatilized, the web does not lose its luster. This is apparently due to the fact that the web moves so quickly past the burner and fresh air nozzle.

It will be evident from the above description that the present invention provides a method and apparatus for drying printing inks and the like which permits a web speed much higher than the presently existing Web speeds with resultant savings in the cost of printing. It will also be evident that the present invention is safer than presently existing methods and apparatus because the solvents within the ink are not burned but instead are merely evaporated and blown away. It has also been found that by the use of the present invention the cost of the drier apparatus has been reduced significantly relative to the cost of conventional driers, this cost reduction being possible because of the smaller size of the drier and the relative simplicity thereof.

The drier of the present invention, when used in connection with a printing press, performs its job so efiiciently that the web feeding speed of the press can be increased from 400 feet .per minute to speeds as high as from 800 to 3600 feet per minute. Although there are a number of factors involved in why the present invention is capable of so substantial an improvement, one important factor is the tremendous velocity of air produced by the nozzle 27. Another factor is the relatively small amount of air used in the slab 61 as compared, for example, to present convection processes. The speed of the air leaving the slot exit 62 has been measured in one embodiment of the invention at 25,000 feet per minute. Of course, depending on the results desired different air velocities can be used and can be produced by changing the capacity of the blower 21. To give an idea as to the relatively small amount of air used, the nozzle 27 may be passing a maximum of 150 to 200 cubic feet per minute per nozzle where the velocity is at the above 25,000 feet per minute value. Such values were obtained where the temperature at the nozzle tip was 1600 F. and the slot opening 62 had a width of between :and 40 thousandths of an inch and a length of 27 inches.

The great speed of air flow from the nozzles 27 changes the usual configuration of the flame to the shape illustrated in FIG. 4, aspirating the flame to the right and into the slab 61 and against the nozzle 27 as illustrated. Sixty to eighty percent of the oxygen required for combustion in the burner is supplied in the air-gas mixture. Because the remaining oxygen is supplied from the air nozzle and because gas expands substantially when heated, the above mentioned high velocity of the air and products-of-combustion is maintained even away from the nozzle. Of course, the oversupply of oxygen or air, as mentioned, prevents combustion of the volatile portions of the coating material.

The velocity of the slab 61 of air and products-ofcombustion is so great that in some situations it is necessary to install a device as shown in FIG. 5 to deliver a flow of air at the end of the drying chamber to break up the pattern of air flow and deflect the gases up the exhaust opening 101. If a device such as the device 100 is not provided the mixture or air and products-of-combustion will hug or move along the surface of the web 102 out the slot or opening 105. The device 100 may be a combination burner and nozzle identical to the burners 11 and nozzles 27 except for the angle of the nozzle 106 which is reversed as shown. Alternatively, the device 100 may be merely a nozzle at any appropriate angle. In all other respects the embodiment of FIG. 5 is identical to the embodiment of FIGS. 1-4.

FIG. 6 shows another solution to the same problem and shows another arrangement for providing additional nozzles and burners where they may be necessary for additional drying. The embodiment of FIG. 6 is identical to that of FIGS. l-4 except that nozzles 200 are provided to balance nozzles 201 whereby the resultant flow of air at the center 202 of the housing 205 is zero and the mixture of air and product-of-combustion can easily move up the exhaust opening 205 located in the center of the housing 206.

FIG. 7 shows a burner 300 which is an improvement over the burner 11. It has been found that over a period of operating time the cast burner 11 tends to deform or bow between A to /2" per foot. Such bowing tends to change the relative positions of the burner and nozzle which interferes with proper operation. Such bowing is avoided by the burner 300 of FIG. 7 which is constructed from off the shelf commercial standard mild steel square tubing. The tubing 303 is drilled to provide a plurali'ty of orifices 301 which are protected by shields 302 to from an elongated U-shaped area 305 for burning gases. The shields 302 are spaced from the tubing by washers 306 which provide air spaces therebetween and between each shield and the tubing. The members 309 are slabs of insulation. The nozzle 307 is identical to the nozzle 27 and the operation of the device of FIG. 7 is identical to the operation described above in connection with FIG. 4. It has been found, however, that the ope-rating temperature of the tubing 303 is much less than that of the conduit 16 and in one test was measured at 600 F. as compared with 1900 F. for the conduit 16.

Of course, various other alternative forms of the invention can be conceived. For example, the exit 62 of the nozzles 27 might be a plurality of holes instead of a slot, the only requirement being that uniform flow of high velocity air is provided. Also, instead of a webfed press or web fed operation, the present invention can be used with a sheet fed operation. The only variation would be the addition of equipment to convey the sheets into proper position during exposure to the drying process.

It will be evident from the above description that the present invention provides a method and apparatus for drying coated or marked materials in a much more rapid fashion than existing methods and apparatus, thus making possible other improvements speeding up marking and coating procedures. Thus the drier of this invention unlike the driers of the prior art is not the limiting factor in the speed of operation of, for example, a printing press. It will also be evident that the drier of the present invention makes unnecessary the use of oxides for drying with 7 their attendant disadvantages. Still further, the method and apparatus of this invention prevents scorching at shutdown, avoids blowing out of the gas flame and makes possible thorough mixing of the products-of-com'bustion and the air jet from nozzles 27 and 307.

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention and the scope of the claims are also desired to be protected.

As used in the claims the terms printing ink and the like and ink are intended to also refer to other coating and marking procedures wherein the coating or marking must be dried. Also, the material referred to in the claims can be many other substances besides paper, such as, for example, textiles, brass (to be dried prior to cleaning or annealing), coated or prefinished steel or aluminum (to mention only a few).

Also, the apparatus of this invention can be used as a heater as well as a drier.

The invention claimed is:

1. A method of drying printing ink and the like after such ink has been applied to a material which comprises directing a flow of heated gaseous fluid at the surface of the material, causing relative movement between the material and the flow whereby said flow wipes across the material and removes volatile portions of the ink, said gaseous fluid including a suificient amount of excess air to prevent combustion of said volatile portions, said relative movement between the material and the flow being at a sufltciently great speed that only said surface is subjected to the high temperature of the heated gaseous fluid and the portion of the material away from said one surface remains comparatively cooler and undamaged.

2. A method of drying printing ink after such ink has been applied to a material which comprises directing the flow of the hot products of combustion of a gas burner at said material, directing a flow of fresh air at said material so as to intercept and mix wit-h said products of combustion prior to said products reaching said material whereby a mixture of products of combustion and fresh air wipes said material, and simultaneously causing relative movement of said material across the path of said flows, said flow of fresh air being at a sufiiicently high velocity and volume to prevent combustion of volatile portions of the ink.

3. The method of claim 2 wherein said relative movement is caused by moving the material through a housing within which is mounted said gas burner.

4. A method of drying printing ink after such ink has been applied to a material which comprises directing the flow of the hot products of combustion of a gas burner at said material, directing a flow of fresh air at said material so as to intercept and mix with said products of combustion prior to said products reaching said material whereby a mixture of products of combustion and fresh air wipes said material, and simultaneously causing relative movement of said material across the path of said flows, said directing of the flow of fresh air being .of a suitable amount of fresh air to provide at least 100% more fresh air than the amount of fresh air at which combustion of any combustible substance in or from the ink or material can occur.

5. A method of drying printing ink after such ink has been applied to a material which comprises directing the flow of the hot products of combustion of a gas burner at said material, directing a flow of fresh air at said material so as to intercept and mix with said products of combustion prior to said products reaching said material whereby a mixture of products of combustion and fresh air wipes said material, and simultaneously causing relative movement of said material across the path of said flows, said fresh air flow being at a velocity of the order of magnitude of 25,000 feet per min., said products of combustion including only 60 to sufiicient oxygen to complete combustion whereby combustion is completed by oxygen in said fresh air flow.

6. Apparatus for drying printing ink and the like after such ink has been applied to a material comprising means for directing a flow of heated gaseous fluid at the material, means for causing relative movement between the material and the flow whereby said flow wipes across the material and removes volatile portions of the ink, said gaseous fluid including a sufiicient amount of excess air to prevent combustion of said volatile portions, said means for causing relative movement being arranged to operate at a sufficiently great speed that .only the surface of the material is subjected to the high temperature of the heated gaseous fluid and the portion of the material away from the material surface remains comparatively cooler and undamaged.

7. Apparatus for drying printing ink and the like after such ink has been applied to a material comprising means for directing a flow of heated gaseous fluid at the material, means for causing relative movement between the material and the flow whereby said flow wipes across the material and removes volatile portions of the ink, said gaseous fluid including a suflicient amount of excess air to prevent combustion of said volatile portions, said means for directing a flow comprising a gas burner, means for supplying a combustible mixture of gas and air to said gas burner, a fresh air nozzle positioned adjacent said gas burner, means for supplying fresh air to said nozzle, a housing within which said gas burner and nozzle are mounted, said means for causing relative movement comprising means for moving the material through the housing, said gas burner being arranged to direct its hot products of combustion at said material, said nozzle being arranged to flow a slab of fresh air directly at said material but also across the path of the products of combustion as they leave said gas burner so as to mix said fresh air and said products prior to their moving against said material.

8. The apparatus of claim 7 wherein said gas burner includes an indentation of U-shaped cross section facing toward said material and orifices opening into said indentation, some of said orifices being in the base of the U-shape of said indentation and some being in the legs thereof, said fresh air nozzle having an exit in the form of a slot which extends parallel to said indentation.

9. The apparatus of claim 8 additionally comprising means for controlling the rate of flow of said gas air mixture to said gas burner, and means for controlling the rate of flow of fresh air to said fresh air nozzle.

10. The apparatus of claim 7 wherein said gas burner includes an elongated tube which is provided with a plurality of orifices along its length, a pair of flame shields secured to said tube on opposite sides of said orifices and providing a shielded burning zone, said fresh air nozzle having an exit in the form .of a slot parallel to said tube and extending along the length thereof.

11. Apparatus for heating comprising a gas burner, a fresh air nozzle positioned adjacent said gas burner, means for moving material past said gas burner and nozzle, said gas burner being arranged to direct its hot products of combustion at said material, said nozzle being arranged to flow a slab of fresh air directly at said material but also across the path .of the products of combustion as they leave said gas burner so as to mix said fresh air and said products prior to their moving against said material.

12. The method of claim 2 wherein the directing of the flow of fresh air is accomplished with a thin slab of air moving at a substantial velocity so that the products of combustion and fresh air impinge against the material while said products and air are moving at substantial velocity, said relative movement of the material across the path of said flows being accomplished at a suffiicently great speed that only the surface of the material against which said products and air impinge is subjected to the high temperature of said products and air and the portion of the material away from said surface remains comparatively cooler and undamaged.

13. A method of drying printing ink and the like after such ink has been applied to a material which comprises directing a flow of heated gaseous fluid at the surface of the material, said fluid being heated to a temperature which would normally damage said material if held at that temperature for a period of time, causing relative movement between the material and the flow whereby said flow wipes across the material and removes volatile por- 10 tions of the ink, said relative movement between the flow and the material being at a sufficiently great speed and said flow hitting a sufficiently small area of the surface of the material that only said surface is subjected to the high temperature of the heated gaseous fluid and the portion of the material away from said surface remains comparatively cooler and undamaged.

References Cited UNITED STATES PATENTS 1,381,806 6/1921 Cunningham 10l-416 2,186,032 1/1940 Mann 10l4l6 2,205,391 6/1940 Brunkow 34-l55 KENNETH W. SPRAGUE, Primary Examiner.

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