US2187837A - Multiple action surface treatment - Google Patents

Description

Jan. 23, 1940. J. A. PAASCHE MULTIPLLE ACTION SURFACE TREATMENT 2 Sheets-Sheet 1 Filed Nov. 19, 1936 fizz/622L 02 i (/2725 A .Paas aha i? Filed NOV. 19, 1956 2 Sheets-Sheet 2 v llllllllllllllllllv Patented Jan. 23, 1940 MULTIPLE ACTION SURFACE TREATMENT Jens A. Paasche, Wilmette, Ill. Application November 19, 1936, Serial No. 111,632

.9 Claims.

This invention relates to improvements in the art of surface treatment and is particularly adapted for applying coating material to.moving surfaces which may travel at variable rates of speed.

3 An object of the invention is to provide improvements in the method and means for eifecting treatment of uniform character per unit area of surface under circumstances where the matter undergoing treatment may be caused to travel through the treating zone at selective variable speeds.

Another object of the invention is to provide improved surface treating means of this character in which the area of the treating zone is selectively variable proportionately to variations in the rate at which a surface to receive treatment may be caused to travel therethrough so that constant uniformity of material application may be obtained.

Another object is to provide improved apparatus including a plurality of air misting devices which are successively and cumulatively operative in proportion to selective increases in the rate of travel of a surface in relative movement through the treating zone thereof to distribute finely divided particles of material in substantially constant quantity per unit area of the surface at any relative speed thereof. Another object of the invention resides in improvements in the method and means for treating a surface wherein solidifiable material is distributed on the surface out of a liquid including a volatile carrying medium and in which volatilization of the carrying medium is accelerated by heating the spray stream.

Another object is to provide improved apparatus of the foregoing general character which embodies air misting mechanism arranged to create a treating zone for applying to the surface of an object in movement through the zone a substance carried in a volatile liquid and in which the misting mechanism and the heating means associated therewith are correlated in operation with the means for moving the object whereby to assure substantially identical treatment per unit area of surface under variable conditions of operation.

Other objects of the invention reside in the provision of improved means for mounting the treating devices upon the air circulating apparatus; in the provision of novel air heating and heat control means; and in general in the provision of the improvements in construction and the novel relationships of parts by which the fore- (CL ill-45) going and other objectsand advantages of the invention may be carried into practice efiiciently and economically.

In the drawings:

Figure 1 is a perspective view of apparatus em. 3 bodying the principles of the invention.

Fig. 2 is a diagrammatic view of a continuous web printing press installation showing the relationship therewith of the improved apparatus of the present invention.

Fig. 3 is an enlarged elevational view of one of the air heating devices partly in longitudinal section.

Fig. 4 is a wiring diagram showing the correlated electrical control circuits for the apparatus. 15

While the invention is susceptible of various modifications and alternative constructions, I have shown in the drawings and will herein describe in detail, the preferred embodiment, but it is to be understood that I do not thereby intend to limit the invention to the specific form disclosed, but intend to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

As will be readily apparent, the invention will possibly be useful in a variety of environments; and it is therefore not intended to limit the scope of the protection aiforded hereby to any specific practical application. Merely as a matso ter of expediency in description, the invention will, however, be referred to in the environment of a printing press installation wherein it is useful in the treatment of a newly printed surface of a sheet of paper for preventing offset of the wet ink to a superimposed surface. In this instance the invention will be described in connection with the high speed, continuous web, rewind printing press organization schematically illustrated in Fig. 2, in which a paper web l0 unwinds from a 40 reel ll and passes between printing rollers l2, after which the printed web travels over a conveyor l3 and is rewound upon a reel l4.

Such presses usually embody a suitable variable speed driving means to cause the web It] to travel at the most eflicient rate of speed for any particular printing operation. For example, the press may be equipped for three predetermined 'web speed ranges in which case the prime mover for the press may be, for example, a motor l5 (Fig. 4) energizable by an operating circuit including a power lead IT, a master switch l8, a lead 9 from the switch, a lead 20 connected with one terminal of the motor, a lead 2| connected with the opposite terminal of the motor, a speed con- 56 trolling resistance device 22 having an operator 23, and a lead 24 which connects through the switch IS with a second power lead 25. By appropriate setting of the resistance 22 the web I0 may be caused to travel selectively at different rates of speed which may be identified generally, for the purpose of description, a first speed of about 200 to 300 feet per minute, a second speed of approximately 400 to 500 feet per minute, and a third speed of around 700 to 800 feet per minute.

To prevent offset of ink from the newly printed surface of the web III to the reverse side thereof as it is rewound upon the reel l4, the printed surface is treated with a discontinuous layer of uniformly distributed, substantially microscopic particles. The latter serve as spacers to maintain the freshly inked surface from the superposed surface of the sheet. The offset preventing particles are produced by creating and directing toward the newly inked surface a mistlike spray of a suitable composition embodying a solidiflable substance such as a resin or lacquer carried in a volatile liquid such as alcohol and carbon tetrachloride. To act efficiently, the offset preventing particles must strike the printed surface properly conditioned (that is, substantially dry) to adhere thereto individually and in spaced relation without producing patches or continuous areas. The individual particles must be present in sufficient number per unit area of surface, however, to maintain a superposed surface uniformly separated therefom. Air treating devices that may be used to create the particles require fairly critical adjustment, both as to the character of spray emitted and the distance of the spray emission point from the sheet surface in order that the particles will strike the surface correctly dimensioned and conditioned. The capacity and pattern of these devices is, of course, bound by certain practical operating limits and the treating zone created by a single device at peak efficiency will properly treat a surface only while the latter is in movement through the treating zone within a determinable optimum speed range.

To meet the variable requirements at diiferent rates of travel of the newly printed web the capacity of the treating zone through which the web must pass is increased proportionately as the speed of the web is increased so as to assure substantially imiform treatment of the printed surface at any selective speed. To this end there is provided a plurality of pneumatically op erated treating devices 21 (commonly denominated air guns) which may be arranged in alined pairs to provide a plurality of gangs identified generally at A, B and C, spaced longitudinally of the path of travel of the web. Three such gangs are herein shown arranged to produce a treating zone indicated generally at 28 (Fig. 1). Each gang is arranged to produce an elongated narrow spray stream which intersects the path of travel of the web l0 and is effective to cover a predetermined aea of the surface to be treated, the arrangement being such that the combined streams of two or more gangs are cumulative to increase proportionately the area of the treating zone. Preferably, the air guns are of the type in which the material to be sprayed and the pressure fluid are comingled at the point of emission of the spray. Reference is here made to my copending application Serial No. 97,185 filed August 21, 1936, which contains a more complete disclosure of an air gun suitable for the present purp l The air guns 21 are preferably supported cantilever fashion over the path of the web III by carrying mechanism generally indicated at 23 which may be of the type described more specifically in my copending application Serial No. 84,- 139, filed June 8, 1936, now Patent No. 2,110,- 052. The carrying mechanism for each gun includes a separate tubular arm 30 (Fig. 1) arranged to pass slidably at one end through a supporting tube 3|. Each pair of tubes in a gang is supported in spaced parallel relation by a rotatable head 32 mounted upon the upper end of a vertically adjustable standard 33. Through this arrangement, vertical, transverse and angular adjustment of the air guns may be effected relative to the surface undergoing treatment. Separate manually operable control shafts 34 for regulating suitable valve means which govern the operation and the character of spray from each gun extend from the guns to one side of the treating zone and are connected by brackets 35 in spaced parallel relation to the carrying arms 30. Where a narrow web is to be treated, one gun of each gang may be shut off.

Operatively arranged to produce a circulation of air through the treating zone 28 and to remove volatilized carrying medium and unapplied treating material therefrom is an exhausting unit 31 which includes a pair of vanes or side walls 38 forming air deflecting members on opposite sides of the treating zone. An exhaust duct 39 between the walls 38 has an inlet opening 40 transversely of the path of the web l0, through which air may be drawn by reduced pressure created in a stack 4| by an exhaust fan (not shown). According to the present invention the air gun carrying mechanism may be associated with the exhausting unit, tubular vertical sockets 42 being secured in any suitable manner to one of the side walls 38 to receive the gun carrying standards 33 adjustably.

The liquid composition to be sprayed may be contained under pressure in a suitable reservoir or tank 43 having thereon a distributor 44 to which are connected conduits 45 for conveying the liquid to the respective air guns 21. The delivery end of each conduit is connected through a nipple 41 to the respective tubular carrying arm 30 through which the material passes to the air gun. Pressure fluid such as compressed air derived from any suitable source (not shown) is delivered through a duct 48 to oil and water separators 49 and thence passes through a duct 50 to a plurality of pressure regulators 5i. One regulator may be provided for each bank of air guns and air conduits 52 provide communication between the respective regulators and air guns. Pressure is maintained within the tank 43 by connecting the same with one of the regulators by means of a conduit 53.

Operation of the air guns is effected by the flow of air therethrough and to control the operation of the guns, therefore, it is only necessary to control the passage of air through each of the respective air conduits 52. For this purpose, a selectively operable control valve 54 (Figs. 1 and 4) is mounted between each conduit 52 and its respective air regulator 5 l By correlating the opening movement of the valves 54 with the operation of the press, the air guns will be caused to respond accordingly to increase or decrease the effective treating area within the treating zone 28. Control means is therefore provided which is operative in the first speed range of the web to actuate one gang of air guns, and which is operative as the speed of the web enters the second and third speed ranges to cause successive and cumulative operation of the remaining gangs of air guns and thereby proportionate variation in the volume of the finely divided treating material projected toward the surface of the web for assuring uniform coverage thereof. To this end the air control valves 54 are biased for movement normally into closed position and have associated therewith operating means such as solenoids 55, 56 and 51 which may be energized through electrical circuits correlated in operation with the speed controlling means of the press to open the valves and eifect operation of the gangs of air guns A, B and C respectively.

Suitable means is provided for energizing the solenoids progressively in accordance with increases in speed of the web. For example, a segment type switch 58 may be associated with the resistance assembly 22 and may have a pivoted contact arm 59 which is operatively associated with the operator 23 and is electrically connected to the press circuit lead 24. The free end of the arm 59 may be in constant circuit making contact with a segment 60 which communicates thorugh electrical leads 6| and 62 with one end of the coil of the solenoid 55. The opposite end of the solenoid coil may be connected through a lead 63, a switch 64 and a lead 65 with the lead I 9 of the press motor circuit to complete the circuit. Accordingly, when the solenoid circuit switch 64 is closed and the press motor I5 is operated at first speed, the solenoid 55 will be energized to open its associated valve 54 and cause operation of the air guns in the gang A. Thus, uniform coverage of the web surface with offset preventing material will take place during the first speed ofthe press.

As the resistance operator 23 is moved to increase the speed of the press motor, the switch contact arm 59 remains in constant electrical contact with the segment 60 and progressively engages successively shorter, stepped segments 61 and 68 which are connected, respectively, through leads 69, 10 and leads H, 12 with the coils of solenoids 56 and 51. The latter solenoids are connected through leads l3 and 14, respectively, with the common lead 63, thus completing the electrical operating circuits for these solenoids which become progressively and collectively energized as the speed of the press is increased to open their respective valves 54 and place the air guns in gangs B and C in operation supplemental one to the other and to the gang of guns A. This assures the desired predetermined coverage of the web surface with ofiset preventing material at the accelerated speeds. On the other hand, successive decreases in press speed automatically bring about substantially proportionate decreases in the number of air guns in operation. If desired, the leads l9, 6!, 69 and 'H may be enclosed at least in part within acable T! (Fig. 1) which carries a detachable plug '18 that may be received in a control box 19, conveniently located near the solenoids, to complete the connection with the respective solenoid leads as already described.

To secure the most efiicient results under certain conditions, the rate of separation of the volatile constituent of the spray is preferably artificially accelerated. For example, the air guns may have to be placed so close to the surface of the moving web as to leave an insuiflcient interval for volatilization between emission and impact of the spray. the web may e trave n at a rate which requires the spray to be projected at such velocity as to preclude proper volatilization, or the selected carrying fluid of the treating composition may be of fairly high surface tension and therefore relatively slow to valatilize. A preferred method of attaining increased volatilization resides in heating the spray stream emitted from the air guns. In one manner of attaining this result the air supply may be heated as by passing the same through electrical air heaters 80. In one form, each heater may comprise an elongated air chamber 8| (Fig. 3) surrounded by a conventional resistance heating coil 62 which is encased in an insulating sheath 83 and an exterior casing 84. One end of the air chamber'communicates with one of the air supply conduits 52 and the opposite end is connected to branch conduits 85 which may have valves 86 in control thereof and which communicate with the tubular carrying arms 30 of the individual air guns in the respective gang being supplied.

, Operation of the heaters 80 is preferably correlated with operation of the air guns and the temperature of the treating composition is maintained uniform While the volume thereof is varied with changes in the speed of the web. To the accomplishment of these objectives, each air heater may be provided with an electrical socket 81 connected to the resistance coil 82 and arranged to receive a detachable plug 88 which is connected to one end of a cable 89 (Fig. 1). The cable houses leads 90 and SH (Fig. 4), and at its opposite end carries a detachable plug 92 which may be received in a suitable socket 93 mounted upon a control box 94. The latter may be disposed in any convenient location, such, for example, as upon the upper end of the air separators 49 (Figs. 1 and 2). In order to avoid operation of the heaters except when the apparatus is in use the heater operating circuit is preferably arranged to be automatically energized only when any of the air guns is in operation. For this purpose the sockets 93 may be connected in parallel in a circuit which may be energized contemporaneously with the energizing circuit for the solenoid 55 and which includes a lead 95 (Fig. 4) which is connected at one end to the solenoid common lead 63 and at its other end to a control switch 96 whence a parallel connection is eflected through a lead 97 with one terminal of each socket. A lead 98 is in parallel connection with the remaining terminal of each socket and is in electrical communication through a resistance device 99 and a lead I 00 with the solenoid lead 62 to complete the heater circuit. The leads 95 and I00 may be enclosed within a cable IM which extends between the control boxes 19 and 94 (Fig. 1).

The resistance 99 is arranged to control the degree to which the heaters will affect the temperature of the air that passes therethrough, and a control knob )2 may be mounted on the box 94 for manually adjusting the resistance.

Thus, the temperature of the heaters may be regulated as required from low through medium to high by an appropriate adjustment of the resistance. As a safety measure, each of the heaters'may be equipped with a cut-out thermostat |63 (Figs. 3 and 4) which will serve to disconnect the heating coil 82 of the heater should the temperature thereof for any reason rise above a predetermined maximum.

From the foregoing it will be apparent that 'ment of the object whereby the present invention provides valuable and important improvements in the art of treating surfaces in movement at widely variable selective rates of travel to effect upon the surfaces treatment of uniform character at any such rate of travel. Rapid, efficient operation and proper conditioning of the treating material are assured by the improved method and means for tempering the material and for regulating the application thereof in accordance with variable operating conditions.

I claim as my invention:

1. Surface treating apparatus of the class described comprising, in combination, means for continuously moving an object having a surface to be treated along a given path, means including a plurality of pneumatically actuated spray creating devices arranged along said path and trained toward said surface, and means for selectively operating said devices in numerical ratio directly proportionate to the speed of movethe amount of spray material deposited per unit area upon said surface will be substantially constant although said object may be moved at variable speeds.

2. Apparatus for surface treating a continuous web traveling at variable speeds comprising, in combination, means located in the path of movement of the web having pressure fluid operated spraying means including a plurality of spraying devices each having a predetermined spraying capacity at a given fluid pressure, speed controlling means for governing the rate of travel of said web past said spraying devices, and means correlated in operation with said speed controlling means to actuate or discontinue operation of successive spraying devices to increase or decrease respectively the effective area covered by said spraying devices proportionately to the speed of travel of the web, whereby to maintain substantially uniform treating efliciency of said spraying means at each speed of the web.

3. In apparatus for spray treating a continuous web, a plurality of successively operable spraying devices each having a predetermined maximum treating capacity and being mounted to act cumulatively upon a web surface, means for moving the web at predetermined variable speeds in a fixed path past said spraying devices, and means for controlling said spraying devices to operate in synchronized numerical ratio proportioned to the speed of movement of the web so that the spray coverage of the web will be substantially constant at said variable speeds.

4. In combination in apparatus of the character described, means for spraying material over a variable area, means for moving a sheet through the effective range of the spraying means, an electric circuit for controlling said sheet moving means to operate at variable speeds, and an electric circuit correlated in operation with said first mentioned electric circuit to control said spraying means in synehronism with said sheet moving means whereby to vary said spray area substantially in proportion to variations in speed of the sheet.

5. In combination in apparatus for treating a rapidly moving printed sheet in the prevention of ink offset, means for spraying toward a surface of the sheet finely divided offset-preventing material and a volatile carrying medium, the spray from said means being such that it would normally contain excessive quantities of carrying medium upon striking said sheet surface, means for heating the pressure fluid constituent of said spray before it leaves said spraying means to accelerate volatllization of the carrying medium during movement of the spray toward said sheet surface, and means for circulating air across said sheet surface through the heated spray for additionally increasing the rate of volatilization of the carrying medium, whereby to form substantially dry particles of the material to provide spacers for maintaining said surface separated from a superposed surface.

6. In spraying apparatus of the character described for association with a machine for moving a sheet in a given path, in combination, pressure fluid operated spraying means mounted to treat said sheet, means correlated with said machine for controlling said spraying means, electrical heating means for increasing the temperature of the pressure fluid delivered to said spraying means, and an electric circuit for controlling operation of said heating means in synchronism with said machine.

7. The method of treating the surface of a variable high speed continuous paper web to prevent ink oflset in printing, which comprises the steps of spraying finely divided particles of offset-preventing material and a volatile carrying medium toward said surface from a position so close thereto that at ordinary temperatures the particles of material would be wet upon impinging the sheet, heating the spray to cause volatilization of substantially all of the carrying medium in the interval between formation and impingement of the particles, and varying the volume of spray in proportion to variations in the speed of the web while maintaining the heat of the spray substantially constant.

8. The method of surface treating an object movable at variable speed continuously in a given path, which comprises the steps of directing a stream of uniformly atomized treating material toward the surface of an object as it passes a point in said path at one speed, and contemporaneously with an increase in the speed of movement of the object directing toward said surface one or more additional streams of the uniformly atomized material cumulatively to the flrst mentioned stream for maintaining the coverage of said surface substantially uniform with the coverage at said first speed.

9. Apparatus of the character described com prising, in combination, means for producing a treating spray within a spray zone, selectively operable means for effecting movement of an object to be sprayed through said zone, and means for heating the spray operable only when said movement effecting means is in operation.

JENS A. PAASCHE.

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