US2025046A - Apparatus for dampening the plate cylinders of lithographic and analogous presses - Google Patents

Description

Dec. $4, 1935. J G K 2,025,046

, APPARATUS FOR DAMPENING THE PLATE CYLINDERS OF LITHOGRAPHIC AND ANALOGOUS PRESSES Filed April 16, 1931 ATTORNEY Patented Dec. 24, 1935 APPARATUS FOR DAMPENING THE PLATE CYLINDERS OF LITHOGRAPHIC AND ANALOGOUS PBESSES John G. Goedike, San Antonio, Tex. Application April 16, 1931, Serial No. 536,584 8 Claims. (!.101-147) (Granted under the act of .Marcha, rose, as amended April so, 192s; 370 o. a.- 75's) This invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to means for dampening the plates employed on lithographic presses for use in off-set lithographic and analogous printing operations and. has for its primary object-the provisions. of a method and apparatus 0 whereby a lithographic plate containing the design to be'printed is dampened by a process of condensation of moisture which is induced by the chilling of the lithographic plate cylinder on which the lithographic plate is mounted, the plate cylinder being chilled by means of a cooling element which forms the low' pressure or cooling side of a refrigerating system, and the amount of moisture condensed on the plates beingcontrolled by the temperatures to which the plate cylinders are lowered.

Another object of my invention-is to provide a cooling element or coil which forms the low pressure or cooling side of a refrigerating system that 'is adapted tobe positioned within the plate cylinders of lithographic presses to chill the same in order to induce condensation of moisture on the external surface of a lithographic .plate mounted thereon for damping the plate.

Another object of my invention is to provide 30 a leak-proof plate cylinder for lithographic and analogous printing presses which is adapted to contain a refrigerating medium.

A further object of myinvention is to provide coupling or uncoupling of a refrigerating apparatus including a cooling element or vaporizer to one end of a plate cylinder or cylinders of lithographic presses for chilling the plate cylinders so as to cause the dampening of a lithographic plate thereon by condensation of moisture from the air without interfering with the working parts on the other side ofthe press.

Hitherto the plates containing the design to he 4 printed which are mounted on the plate cylinders 55 ening has been variablejand unsatisfactory thereby presenting the greatest problem to the lithQ-- a stufing box "and cap which permits the ready ciple.

graphic art. It was believed that a cold plate would not take ink and if a cold plate was employed that the design on the plate would pull the ink and string it out or further if theplate was warm the design on the plate would cause 5 the ink to scum and tint. The employment of the prior methods and apparatus for dampening lithographic plates entails a greater delay after the making'of each print and requires more labor and are not as efiicient as my method and apo paratus fordampening the plates.

It is therefore the purpose of this invention to provide an apparatus which will avoid the disadvantages of the prior methods of dampening the plates used on lithographic and analogous '15 printing operations by the automatic condensation of moisture which result is obtained-by the use of a cooling element or vaporizer which forms the low pressure or cooling side of a refrigerating unit that is adapted to chill or lower the temperature of the plate cylinder used on lithographic or analogous printing operations close to the freezing point oi? water 32 F. for

causing a condensationof moisture to beformed on the plate for dampening. the same, thereby eliminating the use of the present moisting devices such as dampening rollers fed from awater I fountain, increasing the number of prints which may be produced in a given time, permitting the producing of finer prints, making the operation of. producing the prints more efficient and economical, reducing the amount of labor .required and the cost of'making the prints and preventing the ink from being strung out, scum or tint.

My invention is based on the following prin- When air saturated with water in the form of elastic vapor is brought in contact with a colder substance, a part of the water so contained will be deposited on the surface of the 40 colder body in the liquid form, as dew. This takes place because any lowering of the temperature of air which is saturated lessens its capacity for watery vapor and results in the precipitation of the difference between the quantities it can take up at the two temperatures. When the air is not saturated, moisture will still be deposited if the temperature of the colder body be at or below the deW-point--that is, cold enough to reduce the stratum of air in contact with it to a temperature just below that at which the amoimt of water present is sufiicient for saturation. The first case is well illustrated by the film of condensed moisture produced when we breathe upon a plate of glass orof polished metal, which is enin' there when in o eration. 70 g p colder than the saturated air issuing from the lungs; the second by the condensation of water as dew upon the glass and other objects out of doors when the same have been cooled to the dew-point by radiation. The well-known appearance of moisture upon the outside of a vessel of ice water when placed in a warm room is also a case of deposition from partly saturated air.

In order that my invention may be readily understood reference is had to the accompanying drawing in which corresponding parts are indicated by similar reference characters and in which:

Fig. l is a vertical sectional view of my improved dampening apparatus applied to the plate cylinder of a lithographic press;

Fig. 2 is an end view thereof with parts broken away, and.

Fig. 3 is a cross sectional view taken on line 3-'-3 of Fig. 1 looking in the direction of the arrows.

In carrying out my invention the hollow plate cylinder I of a lithographic or analogous press is closed at each end by heads 2. The heads 2 of the plate cylinder I are provided with circum- The plate cylinder I is affixed to rigidly mounted on shaft 4 to rotate therewith. Attached to the outside surface of plate cylinder I by any suitable means is a lithographic plate 5 containing the desigff to be printed. The ends 6 and I of the shaft 4 provide journals which are mountedin bearings 8 and 3' formed in the frame I I of any suitable lithographic press. The end 6 of the. shaft 4 is provided with a reduced end portion II forming a shoulder I2 and contains independent conduits or channels I 3 and I 4 which form portions of an intake and exhaust passageway respectively. The intake channel I3 extends longitudinally from the outer end of the reduced end portion II through the central axis thereof to a point I 5 on shaft 4 within theplate cylinder I where it extends radially to I 6 of the outer surface I! of shaft 4. The exhaust channel I4 extends longitudinally from the shoulder I2 formed by the reduced end portion II to a point I8 within the plate cylinder I where it also extends radially to I9 of the outside surface of the shaft 4.

Within the plate cylinder I and rotatable therewith is a distributing system comprising a tubular element mounted closely adjacent the inner surface 2I of the plate cylinder Iv and provided with a clamping attachment 22 which is circum-.

ferentially arranged around the tubulanelement 23 for holding it in place. The ends 23 and 24 of the tubular element 20 are connected tothe inner ends I 6 and I3 of the intake and exhaust pose of chilling the plate cylinder I to cause a condensation of moisture to form on the exteriorsurface of the lithographic plate I for damp- The high pressure side of the refrigerating system compri s a compressor 35; condenser 36,

t a liquid receiver I and expansion valve 33 which are connected to the device 20 of my invention by means of conduits 21 and 28.. This connection is specifically made as follows. Adjacent the end below the dew point of the atmosphere surround- 6 of the shaft 4 is a housing 23 which is at-' tached to the outside frame II! of the press by any suitable means such as bolts and is joined to the external stationary conduit 21 which passes through the frame thereof for making a con- 5 ducting passage between the conduit 21 and the internally rotary conduit I4, a similar connection being made between the external stationary intake conduit 23 and the internal rotary conduit I3 by means of a fluid tight joint formed in any '10 suitable manner as by means of another housing in the form of a cap 3i which is secured in place by any suitable means such as bolts 32. Any suitable leak preventing means such as a resilient washer 33 may be inserted between the 15- frame IO'and housing 29. as shown.- A hole 34 may be provided for permitting the reduced end portion II of the shaft 4 to be lubricated.

In chilling the plate cylinder I for causing the dampening of the lithographicplate 5' attached 20 thereto by the condensation of moisture thereon the compressor 35 forces the refrigerant under high pressure in a gaseous form into the condenser 36 which changes the gas into a liquid by giving up its heat to' the medium about the 25 condenser, the refrigerant flowing from-the condenser 33 into the liquid receiver 31 from where Y it is conducted by the stationary intake conduit .23 through the expansion valve 33 then through the rotatable intake channel I3 provided; in the end 6 of the shaft 4 from where it enters the end 23 of the rotatable tubular element 20.

The tubular element 20 constitutes the cooling element or vaporizer and forms the low pressure side of the refrigerating system. The refrigerant in the cooling element or vaporizer 23 is changed back into a gaseous form by the vaporizer absorbing the heat from the plate cylinder I which reduces the temperature'thereof 40 ing the plate cyllnder'to cause a condensation of moisture to form on the exterior surface of the lithographic plate 5 mounted thereon. The sole source of the condensed moisture on the plate is the atmosphere surrounding the plate. I

The plate cylinder I when rotated by the gears 3 rotates the shaft.4 and the tubular element 20 attached thereto thereby keeping the metal plate cylinder I chilled at all points as near as practical below the dew point of the atmosphere to cause a condensation of moisture to form on the ex-. terior surface of the lithographic plate '3 ate tached thereto thereby providing a dampened surface thereon. The refrigerant finally works its way through the end 24 of the rotatable tubular, element 20 where itenters the inner end I3 of the rotatable exhaustchannel I4 and leaves I at the other endthereof emptying into the housing 29 to be discharged into the stationary exhaust conduit 21 which draws the refrigerant from the housing 23 creating a vacuum therein thereby causing the refrigerant-toflow from the rotatable exhaust channel I4 into the housing 29 and be conducted back through the suction port 39 into the compressor 35 of the refrigeratizng system by means of the stationary conduit It will thus be seen that I have provided ,a highly novel, simple and eflicient apparatus for. dampening the platecylinders of lithographic and analogous printing presses that is well adapted for all the purposes designated by any refrigerating system employing compression, vacuum, absorption or any other type and which will permit the use of any refrigerant such as air, ammonia, methyl chloride, sulphur dioxide and various other refrigerants. Even though I have herein shown and described myapparatus for carrying out the invention as comprising certain structural elements it is nevertheless to be .understood that changes may be made therein without departing from the spirit or scope of my invention.

Having described my invention what I claim 3 as new and wish to secure by Letters Patent is:

1. A mechanism for lithographing comprising a movable lithographic surface mounted on a fixed frame, a closed refrigerating system comprising a refrigerating mechanism connected to said frame and means for reducing the temperature of said lithographic surface substantially to the dew point of the surrounding atmosphere for condensing a film of atmospheric moisture there on, the sole source of the condensed moisture comprising the atmosphere surrounding the surface, said means being mounted to move with said surface and forming the low pressure side of said v prising a refrigerating mechanism refrigerating system.

2. A mechanism for lithographing comprising a movable lithographing surface mounted on a fixed frame, a'closed refrigerating system ,com-

connected to said frame and cooling coils for substantially reducing the temperature of said surface to the dew point of the atmosphere surrounding the surface to produce a condensation of moisture therea on, the sole source of said condensed moisture comprising the atmosphere surrounding the surface, said coils being integrally movable with said lithographingsurfacef and mounted closely adjacent thereto.

3. A mechanism for lithographing comprising a hollow plate cylinder having a lithographic pl'ate mounted thereon, a closed refrigerating system comprising a refrigerating mechanism removably connected to said plate cylinder and cooling coils hollow lithographic plate cylinder having a lithographic plate thereon and mounted on and rotatable with a shaft,. a fixed frame for movably supporting said shaft, a closed refrigerating system comprising a refrigerating mechanism detachably connected to said frame, and a tubular refrigerating element forming the cooling side of said refr gerating system for substantially reducing the temperature of said plate cylinder? to the dew point of the atmosphere surrounding the plate to produce a-film'of moisture on the external surface of said lithographic plate, the sole source of said film of moisture comprising the'at mosphere surrounding the plate and the said refrigerating element mounted closely adjacent the a said cylinder, and means operatively connecting inner surface of said plate cylinder and integrally movable with said plate cylinder and shaft.

5. A mechanism for lithographing comprising a hollow cylindrical lithographic surface mounted on and rotatable with a shaft provided with inlet 5 and outlet channels, a fixed frame for supporting saldshaft, a closedrefrigerating system comprising a refrigerating mechanism detachably connected to said frame and means for substang tially reducing the temperatureof' said surface a to the dew point of the atmosphere surrounding it, to produce a film of moisture on said lithographic surface, said means consisting'of a tubularcooling element having the ends thereof connected to ends of said inlet and outlet chan 15- nels on said shaft, said tubular cooling element forming the low pressure side of the said refrigerating system.

6. A mechanism for lithographing comprising a hollow cylindrical lithographic surface mounted 20 on and rotatable with a shaft having independent inlet and, outlet channels therein, a fixed frame for rotatably supporting said shaft, a closed re-' frigerating system including a stuffing box and cap detachably connected to said frame, means for substantially reducing 'the temperature of said surface to the dew point of the atmosphere surrounding it, to produce a film of moisture on the external surface thereof, said means comprising a cooling coil circumferentially mounted so within said lithographic surface to rotate therewith and having the ends thereof connected to the inner ends of the said inlet and outlet cha.n-,

nels in said shaft the said cooling coil forming the low pressure side of said refrigerating system, and clamping means for supporting said cooling coil.

7. In a planographie printing-press including a revoluble cylinder adapted to have the printingplate mounted thereon, the combination with 40 said cylinder of conduit'means in and rotatable with said cylinder and forming the low-pressure gas-expansion portion of a cooling system, the complementary relatively-stationary high-pressure compression" portion of said system external to said cylinder, and means operatively connecting said two portions .together, said cooling system being adapted to reduce the temperature of the plate sufficiently to cause a deposit of dew on the plate from moisture-laden adjacent air.

8. In a planographic printing press including a revoluble cylinder adapted to have the printingplate mounted thereon, the combination with said cylinder of conduit means in and rotatable with said cylinderand forming the low-pressure gasexpansion portion of a cooling'system, the complementary relatively-stationary high-pressure compression portion of said system external to said two portions together extending through one end only of saidcylinder, said cooling system being adapted to cool saidplate suillciently to cause adeposit of dew on the plate from moisture-laden adjacent air.

JOHN G. GOEDIKE.

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