EP0916492B1

EP0916492B1 - Device for supplying liquid cleaner

Info

Publication number: EP0916492B1
Application number: EP97119983A
Authority: EP
Inventors: Marco Corti; Riccardo Fumagalli
Original assignee: Elettra Srl
Current assignee: FINELETTRA INTERNATIONAL S.A.
Priority date: 1997-11-14
Filing date: 1997-11-14
Publication date: 2001-09-19
Anticipated expiration: 2017-11-14
Also published as: DE69706868D1; ATE205783T1; EP0916492A1; ES2161407T3; DE69706868T2; DK0916492T3

Abstract

The branches of the channels for feeding the cleaning fluids, formed in the dispensing bar (1), continue to fork (B1, B2, B3, B4, B5, B6, B7, B8, B9, B10, B11, B12, B13, B14, B15), optionally finally splitting into three-way branches (T1, T2, T3, T4, T5, T6, T7, T8), until each dispensing hole (10) is fed by its own channel, so that the flow of fluids is distributed essentially in equal amounts and at the same pressure between the various dispensing holes (10) in the bar. The cleaning liquids are fed by respective reciprocating positive displacement pumps (63, 163) which are activated by pneumatic actuators (65, 165) having a piston which is suitably larger than the piston (64, 164) of the said pumps and being activated by the stream of air produced by the same source and at the same pressure as that conveyed to the dispensing bar, mixed together with the liquids dispensed by the pumps, in order to convey and atomize the said liquids. This ensures that the delivery pressure of the cleaning liquids is always correlated to and greater than the pressure of the stream of air, even when the latter is subject to variations in pressure. <IMAGE> <IMAGE>

Description

The present invention relates to apparatuses for automatically cleaning the inking rollers and the natural-rubber covered cylinders of printing machines, hereinafter referred to as "rubber-covered cylinders", as described in Italian patents Nos. 1 257 766 and 1 257 769, application No. BO95A000432 (now patent No. 1 279 630, published on 14 March 1997) and European patent application EP 0 636 476.
Document EP 0 636 476 A discloses an apparatus for dispensing fluids for cleaning the surface of rubber-covered cylinders and inking rollers of printing machines, of the type that comprises at least one row of means for dispensing the said fluids, said row being parallel to the surface to be cleaned and said dispensing means being located on a dispensing bar having transverse dispensing holes which convey the fluid to the said dispensing means and are in turn connected to channels obtained along one face of the said bar and closed by sealing means so as to form ducts.
Document US 4 540 445 A discloses an apparatus for cleaning gripper assemblies on printing presses in which a single duct for the cleaning fluid is subdivided with "Y" shaped branches and in which each branch deriving from the said subdivision feeds a plurality of dispensing nozzles arranged in series.
Document GB 569 446 A discloses an apparatus for applying ink to the design cylinder of a rotary printing press of the type that comprises at least one row of openings for dispensing the ink, said row being parallel to the surface of the cylinder and said openings being located on a dispensing bar and connected to ducts connected in turn to other feed ducts which are arranged in parallel to each other, come together at forks and gradually decrease in number until they join up with a single fluid feed duct.
Document DE 196 19 143 A discloses an apparatus for cleaning the surface of cylinders of printing machines which employs a felt pad is impregnated with the cleaning fluid and which can be brought in contact with the cleaning cloth.
According to the present invention there is provided an apparatus for dispensing fluids for cleaning the surface of rubber-covered cylinders and inking rollers of printing machines in which said cleaning fluids consist of a mixture of liquid and air. The apparatus comprises at least one row of means for dispensing the said fluids, said row being parallel to the surface to be cleaned and said dispensing means being located on a dispensing bar having transverse dispensing holes which convey the fluid to the said dispensing means and are in turn connected to channels obtained along one face of the said bar and closed by sealing means so as to form ducts, these channels being connected to other feed channels which are arranged in parallel to each other, come together at forks and gradually decrease in number until they join up with a single fluid feed duct. The apparatus according to the invention is characterized by the fact that (a) each fork in the said channels is essentially "Y"-shaped, i.e. with one leg and two diverging branches and is realized, as regards its leg part before the branching-off point, along a rectilinear path, and (b) the total number of forks is such that each dispensing hole is fed by a single final branch. There is also the option of connecting porous inserts to the dispensing holes instead of the usual nozzles, these inserts coming into direct contact with the cloth for cleaning the rubber-covered cylinders.
The features of the invention, together with the advantages that derive therefrom, will be apparent from the following description of some preferred embodiments illustrated by way of example in the figures of the accompanying drawings, in which:

Fig. 1 is a cross-section on I-I in Figure 2 showing the improved bar according to the invention, in the version equipped with nozzles for dispensing the cleaning fluids;
Figs. 2 and 2a are a plan view from above, split into two portions with the cutting line running along the midpoint, of the bar in Figure 1 showing the channels which ensure that the cleaning fluids are distributed uniformly to the various nozzles;
Figs. 3 and 3a are a plan view from above, split into two portions at the midpoint, of a variant embodiment of the bar showing the channels which ensure that the cleaning fluids are distributed uniformly to the various nozzles;
Fig. 4 illustrates an enlargement of the final branch of the channels that feed the nozzles in the bar shown in Figures 3 and 3a;
Fig. 5 illustrates additional details of the bar of Figure 3, in cross-section on V-V;
Figs. 6 and 7 illustrate, in cross-section and in two different stages of operation, a cleaning fluid dispensing bar which incorporates porous inserts instead of the usual nozzles;
Fig. 8 is a view of the front of the bar shown in Figures 6 and 7.

In order to gain a better understanding of the objects that the invention intends to achieve, it would be helpful briefly to recall that some of the apparatuses to which reference is made - i.e. those designed to clean the rubber-covered rollers of printing machines - comprise a fixed bar 1 made of a lightweight alloy, which is positioned parallel to and a short distance from each rubber-covered cylinder 2 and which, on its side facing the said cylinder, carries a longitudinal straight recess 3 in which a presser element 4 with a yielding elastic membrane 5 is guided. The same bar 1 also houses the pneumatic actuators 6 which, on command, push the presser element 4, 5 against the cylinder 2 so as to bring the latter into contact with the intermediate cloth 7 onto which cleaning fluids are sprayed by nozzles 9 mounted in one or more seats 8 formed in that side of the bar that faces the cloth. These nozzles connect up, via holes 10, with channels 1000 milled along a flat face of the said bar on which a gasket 12 is then placed and a covering means 13 fixed by means of screws 14, thereby turning the said channels into proper ducts. These channels are symmetrically connected to other feed conduits which are arranged in circuits flowing parallel to each other, come together at forks and gradually decrease in number until they join up with a single fluid feed duct 15 located at one end of the bar 1. In the Italian patent No. 1 279 630 mentioned in the introduction to the present description, the fact was claimed that each fork in the said channels is essentially "Y"-shaped and occurs in a straight section of duct, and that the channels produced by the fork are structured such that they offer essentially the same degree of resistance to the passage of the fluids, so that the latter split into flows of essentially equal volume at each fork in the duct. The number of forks is such that each terminal channel is of limited length and feeds a limited number of nozzles 9. In the embodiment illustrated in the Italian patent No. 1 279 630 cited above, the terminal channels fed three nozzles in series. In the embodiment according to the present invention, the channels continue to fork until each terminal channel produced by a fork feeds a single nozzle, in order to ensure an even more uniform distribution of the cleaning fluids to the various nozzles of the apparatus.
In Figures 2 and 2a, the reference numeral 15 denotes the duct located at one end of the bar and connected to the cleaning fluid delivery system. As already mentioned, the cleaning fluid consists of a mixture of a suitable cleaning liquid and air. The duct 15 communicates, via the perpendicular hole 16, with a first channel 100 formed longitudinally in the bar 1 and which, before it reaches the middle 18 of the bar, forks at B1 into two opposite straight ducts 101, 201 which, before they reach the middle of each respective half-bar, fork at B2 and B3 respectively, forming corresponding pairs of identical, mutually aligned ducts 102, 202 and 103, 203 which in turn fork at B4, B5 and B6, B7 respectively forming pairs of ducts 104, 204, 105, 205 and 106, 206, 107, 207 which then fork again, for the last time, at B8, B9, B10, B11 and B12, B13, B14, B15 respectively, which, via their respective conduits 108, 208, 109, 209, 110, 210, 111, 211, 112, 212, 113, 213, 114, 214 and 115, 215, feed the holes 10 of associated nozzles 9. Following each main channel are two initially straight channels located a short distance from each other and parallel to and equidistant from the channel upstream. The common wall via which the channels formed by each fork join up with the channel upstream has a "V" shape when viewed from above and has a sharp point. Of the two arms that follow each fork, one has a "Z" or "S" shape, and the other a "U" or "C" shape, as may be seen in the appended drawings.
The reference numeral 26 denotes straight milled portions formed in the base of the conduit 11 which carries the channels for conveying the cleaning liquids. These milled portions contain the threaded blind holes 114 in which the screws 14 engage in order to screw down the components 12, 13 which define the said channels according to the known art (Fig. 1).
In order to spread losses in pressure equally, the channels formed by each fork are of appropriate depth and width, as may be seen in Figure 1. For example, in the bar produced by the applicant and illustrated in Figures 2 and 2a, and which has fifteen forks and sixteen dispensing nozzles, the initial conduit 100 is approximately 10mm deep and approximately 5 mm wide, while the arms of the final forks are approximately 3 mm wide and approximately 2.5 mm deep.
The bar illustrated in Figures 3 and 3a actually has twenty-four nozzles supplied by channels containing fifteen forks, essentially as in the previous bar except that the final forks subsequently split into three-way branches T1, T2, T3, T4, T5, T6, T7, T8, immediately after their straight sections, as illustrated in the detail shown in Figure 4. These branches are symmetrically and centrally positioned relative to the fork, with one arm having an "S" or "Z" shape, one having a "U" or "C" shape and the intermediate arm having a rounded "L" shape, each of the three arms feeding the hole 10 of one nozzle 9.
Figure 5 illustrates how, in the variant embodiment of Figures 3 and 3a, the channels for conveying the cleaning fluids also have differing widths and depths in order to compensate for losses in pressure. In the bar produced by the applicant, the initial ducts are, for example, 4 mm wide and 8 mm deep. After the first fork their width goes down to 3 mm and their depth to 6 mm. After the next fork their width remains the same but their depth is reduced to 3 mm. At the next fork their depth remains the same but their width is reduced to 2 mm. The arms of the final fork are 2.5 mm deep and this depth, and the width of 2 mm, remain unchanged to the end. The detail in Figure 4 shows that the outer arms of each final three-way branch are oriented tangentially to the holes 10 feeding the associated nozzles, while the inner arm is centred with respect to its hole 10 which, like all the other holes, has a diameter of 3 mm.
With reference to Figures 6, 7 and 8, according to a variant embodiment of the invention, the nozzles 9 can be replaced by a straight pad 70, made of any suitable porous material, housed in a straight recess 71 formed in the active face of the bar 1, parallel to the recess 3. At the base of the recess 71 there is a small continuous chamber 72 which acts as a reservoir and into which the holes 10 for dispensing the cleaning fluid open. The pad 70 may advantageously be formed by a plurality of inserts 70' which have the same dimensions and are identical to each other, except for the end inserts 70" which have one rounded end so that they can fit in a leaktight manner into the corresponding ends of the recess 71 (Fig. 8). The inserts 70', 70" are held in the recess 71 by suitable means so that, if need be, they can be easily removed, for example so that they can be cleaned or replaced periodically. To this end the inserts 70', 70" are dimensioned such that they can be inserted very accurately into the recess 71 and present a longitudinal bore 73 through which a retaining rod 74 passes, which also passes through bores formed in the ends of bar 1, the threaded ends of the said retaining rod being fixed to the ends of the bar by means of nuts 75.
Figure 6 shows that the pad 70 is preferably positioned so that its face is in view and lies in the same plane as the wall of the bar 1 which comes into contact with the cloth 7 when the presser element 4, 5 is in the retracted rest position. At this point, the liquid to be sprayed is fed via the holes 10 into the small reservoir 72 from which it is fed to the pad 70 which uniformly wets the cloth 7. During this stage the cloth 7 is preferably stationary. Once the liquid has been dispensed, the cloth 7 is moved until its wetted part is in front of the presser element 4, 5 which is then activated, as shown in Figure 7, so as to clean the rubber-covered roller 2.

Claims

Apparatus for dispensing fluids for cleaning the surface of rubber-covered cylinders (2) and inking rollers of printing machines said cleaning fluids consisting of a mixture of a liquid and air, of the type that comprises at least one row of means (9) for dispensing the said fluids, said row being parallel to the surface to be cleaned and said dispensing means (9) being located on a dispensing bar (1) having transverse dispensing holes (10) which convey the fluid to the said dispensing means and are in turn connected to channels obtained along one face of the said bar and closed by sealing means (12, 13) so as to form ducts, these channels being connected to other feed channels which are arranged in parallel to each other, come together at forks and gradually decrease in number until they join up with a single fluid feed duct (15),
characterized by the fact that
- each fork in the said channels is essentially "Y"-shaped, i.e. with one leg and two diverging branches and is realized in its leg part before the branching-off point, along a rectilinear path, and

- the total number of forks is such that each dispensing hole (10) is fed by a single final branch.
Apparatus according to Claim 1), characterized in that each one of the two diverging branches (B8, B9, B10, B11, B12, B13, B14, B15) of the final forks branches off into a group composed of three branches (T1, T2, T3, T4, T5, T6, T7, T8) each of which feeds a dispensing hole (10).
Apparatus according to Claim 2), in which a dividing wall is provided in the rectilinear portion of the duct before the branching-off point in alignment with the midpoint of the central branch of the group of three branches (T1, T2, T3, T4, T5, T6, T7, T8) and these three branches are of the same width as each portion of the duct divided by the dividing wall.
Apparatus according to Claim 2), in which the dispensing holes (10) have a diameter which is greater than the width of each branch of the group of three branches.
Apparatus according to Claim 4), in which the dispensing hole (10) of the central branch of the group of three branches (T1, T2, T3, T4, T5, T6, T7, T8) is co-axial with the said central branch, while the dispensing holes of the outer branches are positioned so that their circumference lies tangentially relative to the said outer branches.
Apparatus according to the preceding claims, characterized in that, in order to compensate for losses in pressure resulting from the various branches and from the increased overall width of the channels for conveying the cleaning fluids, the depth of these channels decreases progressively in the direction of the terminal dispensing holes (10).
Apparatus according to Claim 1), in which the depth of the final forks is approximately 2.5 mm and their width is approximately 3 mm, the same as that of the holes (10) for feeding the nozzles.
Apparatus according to Claim 2), in which the depth of the final three-way branches is approximately 2.5 mm and their width is approximately 2 mm, while the dispensing holes (10) which connect up with these branches are approximately 3 mm wide.
Apparatus according to the preceding claims, in which the holes (10) which finally dispense the cleaning fluids connect up with a straight chamber (72) which acts as a reservoir and opens at the base of a straight recess (71) in the dispensing bar, formed parallel to the recess (3) housing the presser element (4, 5) and engaging with a pad (70) made of any suitable porous material which is permeable to the said cleaning fluids, one face of which is in transverse contact with the cleaning cloth (7) when the said presser element is in the retracted rest position, so that the fluid dispensed by the said holes (10) passes through the said pad and wets the cloth uniformly.
Apparatus according to Claim 9), in which the face of the porous pad is in view and lies essentially in the same plane as that surface of the dispensing bar (1) with which the cleaning cloth (7) comes into contact and over which it slides when the presser element (4, 5) is in the retracted rest position.
Apparatus according to Claim 9, in which the porous pad is formed by a plurality of inserts (70') placed next to each other and having the same dimensions, except for the end inserts (70") which engage in corresponding rounded ends of the housing recess (71).
Apparatus according to Claim 11), in which the inserts that form the porous pad are provided with at least one through bore (73) and have a small retaining rod (74) passing through them and also passing through end bores formed in the dispensing bar (1), the threaded ends of the said retaining rod being fixed to the bar with nuts (75).