FR2644713A1 - DEVICE AND METHOD FOR CLEANING A CYLINDER - Google Patents

Abstract

Device for cylinder cleaning comprising a pocket 100 and a protective film 130. The pocket 100 is longitudinal substantially as long as the cylinder 50 to be cleaned and can be opened at will along a line to allow the expulsion of a pasty mixture. 10 pressure stripper. The device also comprises a flexible rectangular protective film 130 inert to the mixture, which film extends the pouch over its entire length and over a width greater than the circumference of the cylinder.

Description

_-1

  DEVICE AND METHOD FOR CLEANING A CYLINDER

  The present invention relates to a device for cleaning a cylinder associated with a counter-cylinder, and to the cleaning method using this device. The need to clean a cylinder is encountered in the industry on numerous occasions such as, in a non-exhaustive manner, in rolling mills, in rotary machines machining elements in plate and in rotary printing machines. The current cylinder cleaning technique has however been more developed in relation to the last type of machine mentioned in particular for the ink cylinders and distributors which must be washed of any residue.

  ink then dried at the end of each production cycle.

  The presentation DE 2 804 801 discloses a device comprising a cleaning tape unwound from a store drum. This strip passes against a cleaning product coating ramp, then between the cylinder to be cleaned and a cylindrical brush pressing it against the cylinder. Finally, this strip is wound at the

  cylinder outlet on a second receiving drum.

  Another known device comprises a bar for spraying cleaning liquid against the cylinder to be cleaned associated with a ramp of rotary brushes also applied against the cylinder. Another device comprises, applied against the cylinder to be cleaned, a second porous cylinder inside which a cleaning liquid is injected. This porous cylinder

  then acts simultaneously as a sponge and scraper.

  Mention should also be made of the description GB 2 081 181 disclosing a sheet, one of the faces of which can catch debris or residue in several places and which is intended to be passed between the cylinder to be cleaned and its counter-cylinder. The cleaning face of this sheet comprises a screen of thin thickness of flexible polymer constituting on this face of the cells inside which is deposited a sticky layer of thickness less than the screen. Thus, this sheet turns out to be non-sticky when it is contained without pressure within a stack of other sheets, but becomes sticky for debris when the cylinder and the counter-cylinder sufficiently crush the weft to bring the layer into contact. sticky cleanser. Satisfactory for cleaning a homogeneous ink layer on smooth cylinders, the previously mentioned devices prove completely unsuitable for cylinders having either a very fine screen or a surface porosity, the depth of the cells of which varies between a few microns and several tenth of a millimeter, which screens or cells are gradually plugged by solid ink residues. In such circumstances, it would be useful to be able to use much more aggressive liquid chemicals, which is hardly achievable with current devices known to be hazardous.

  of potential splashes and their consequences.

  -3- The object of the present invention is a device for performing a powerful and effective cleaning of a cylindrical surface whatever its chemical and mechanical characteristics in surface as well as those of debris or residues. Obviously, this device must not involve any risk for the adjacent equipment and for the operator using this device. In addition, the cleaning process using this device must be simple to be understandable.

and easily executable by all.

  These aims are achieved by means of a cylinder cleaning device which comprises a longitudinal pocket substantially as long as the cylinder to be cleaned, containing a pasty stripper mixture and which can be opened at will along a line to allow the mixture to be expelled under the pressure effect, as well as a flexible rectangular protective film inert to the mixture, which film extends the pocket over its entire length and over a width greater than the circumference of the cylinder. Preferably, the opening line of the pocket is initially closed by a longitudinal safety clip. For cylinders covered with ink, the pasty stripper mixture can advantageously comprise: - 76 to 98 parts by weight of sulfuric acid of concentration between 80 and 100 s, - 3 to 18 parts by weight of chromic acid of concentration between 80 and 100 b, - 1 to 15 parts by weight of micron powder inert with sulfuric and chromic acids. So the film

  flexible protection can be made of polyethylene.

  -4- The pocket can then comprise a first internal pocket made of polyfluoro-olefin and containing the stripping paste as well as a second external pocket made of

  polyvinyl chloride and containing the first pocket.

  According to a first embodiment of the device, the protective film can extend the pocket backwards relative to the direction of rotation of the cylinder, and the pocket can then open under the film along a line along its rear edge . Useful then, the pocket can be provided on its internal face oriented towards the cylinder with fixing means

  temporary pocket on the cylinder.

  According to a second embodiment, the protective film can extend the pocket forward relative to the direction of rotation of the cylinder, and the pocket can

  open along a line along its rear edge.

  The first embodiment of the device according to the invention is very particularly advantageous when the cleaning process consists in: fixing the pocket longitudinally on the cylinder, - making the cylinder perform three quarters of a turn thus partially winding the film on the cylinder, - lifting the pocket to fold the rear edge of the film against the cylinder, - if present, remove the safety clip from the pocket, fix the pocket on the external face of the film, - stick the two lateral edges of the protective film on the cylinder using adhesive strips, - bring the corresponding counter-cylinder into contact and rotate the cylinder and the counter-cylinder together, thus causing the pasty material to be expelled from the bag and then forming an active bead of

  pasty material between the two cylinders.

  The second embodiment of the device according to the invention is particularly advantageous when the cleaning process consists in: fixing the front edge of the protective film longitudinally on the cylinder, - making the cylinder perform three-quarter turns thus partially winding the film on the cylinder, - lift the front edge of the film to fold the pocket against the cylinder, - if present, remove the safety clip from the pocket, - fix the front edge of the film on the external face of the part of the same located in front of the pocket, - stick the two lateral edges of the protective film on the cylinder by means of adhesive strips, - put the corresponding counter-cylinder in contact and rotate the cylinder and the counter-cylinder thus causing the expulsion of the material pasty out of the pocket then the constitution of an active bead of

  pasty material between the two cylinders.

  It is useful to rotate the cylinder and the counter cylinder together for between 10 and 90 minutes depending on the nature of the residues &

  clean and the composition of the stripper mixture.

  According to another advantageous characteristic, the method using the device according to the invention may, after having made the cylinder and the counter-cylinder rotate together, consist of: or -6-- - 8ter the lateral adhesive strips, - rotate the cylinder half a turn back, cut the protective film on a line diametrically opposite the bead, - rotate the cylinder half a turn forward, - pinch the protective film around the bead of feces to create a recovery pocket, which is gradually pulled out of the cylinder by taking the adjacent sections of protective film which

wipe the cylinder.

  The invention is described below in more detail with the aid of non-limiting exemplary embodiments illustrated in the accompanying drawings, in which: - Figure 1 is a perspective view of a first embodiment of the device placed on a cylinder and the component parts of which are cut

  for a better understanding of the under-

  adjacent, - Figures 2a to 2e are five sectional views illustrating a first mode of installation of the device according to Figure 1, - Figures 3a to 3e are five sectional views illustrating a second mode of installation of the device according to Figure 1, - Figures 4m to 4q are five sectional views illustrating the process for removing the device from the cylinder, and - Figures 5s to 5w are five. sectional views illustrating a method of installing a second mode of

realization of the device.

  - 7 - In the remainder of this description, the terms "front" or "front" as well as "rear" should be understood with respect to the direction of rotation of the cylinder. For example, in FIG. 1 illustrating a part of cylinder 50 to be cleaned and turning anticlockwise, a front or front edge corresponds to a part of the part oriented to the left while an edge rear corresponds to a part oriented to the right, In this figure 1 is also illustrated a

  pocket part 100 which as a whole is rectilinear.

  The length of this pocket 100 is substantially identical to that of the cylinder 50 to be cleaned, preferably in fact shorter on the order of a centimeter on either side

  to provide a fixing zone on the cylinder 50.

  This pocket 100 is fixed longitudinally to the cylinder 50 temporarily by means of attachment 125 which can be, for example, an adhesive strip on both sides or a magnetic strip reacting to the steel of the cylinder 50. This pocket 100 may be formed of a plastic sheet folded from the front and the side edges of which are closed by welding or by an adhesive strip 128 thus leaving an opening line on its rear edge. Depending on the content intended to be enclosed in this pocket 100, the latter may in fact be composite, that is to say formed by a first internal pocket 110 containing a stripping product 10, this first pocket itself being contained inside a second external pocket 120 which is fixed to the

cylinder 50 by means 125.

  Once the product 10 is placed either in the simple pocket 100 or in the internal pocket 110, the rear opening of this simple pocket or of the external pocket 120 is closed in a sealed but not definitive manner. This closure can be achieved by a longitudinal clip 122

  with a flexible internal anti-slip bar

  back or by a series of glue or solder points or any other means that can be removed or broken

only at will.

  A flexible protective film 130 extends rearwardly the upper face of the pocket 100 over its entire length. This film 130 is fixed to this upper face of the pocket by means 132 which can be a thread of glue or a double-sided adhesive strip or a single-sided adhesive strip which simultaneously covers the edge.

  front of the film 130 and the upper face of the pocket.

  For increased security, it is also possible to envisage fixing the front edge of the film 130 under the front fold of the pocket 100, that is to say close to the first fixing means 125. This film 130 therefore has a substantially equal length. to the pocket 100, therefore of the cylinder 50. In fact, as for the pocket 100, this length is slightly less, on the order of a centimeter, than that of the cylinder, thus leaving sufficient space between these lateral edges and the cylinder to apply to it. an adhesive tape for fixing the film 130 to this cylinder 50. The width of this film 130 must be greater than the circumference of the largest cylinder 50 for which this device is provided, knowing that for lower cylinders this width can be reduced by cuts. For distributing cylinders within rotary printing machines, this film width

is of the order of a miter.

  The stripping mixture 10 is in the form of an isotropic paste which is sufficiently soft to be able to subsequently be inserted into the smallest cells of the cylinder 50 without, however, being able to escape under pressure through small leakage channels of the means of fixation. This paste essentially consists of an active agent depending on the chemical composition of the residues or ink to be cleaned and a thickening agent such as a micron powder giving the paste its quasi-thixotropic property. For example, for a cylinder 50 to be cleaned of ink residue, the active agent may be a mixture of about 90 to 95% sulfuric acid and 5 to 10% concentrated chromic acid. The binder can then be a micron silica powder such as that sold under the brand "AEROZIL

  "up to 1 to 10% of the total pasty mixture.

  We can also consider the use of carbon black as long as the particles making up this powder are rough, thus presenting a larger apparent surface against which the liquid is applied.

active by surface tension.

  The materials constituting the pocket 100 and the protective film 130 must obviously be inert with respect to the stripping mixture 10. In the example cited above used to clean a cylinder 50 of traces of ink, the internal pocket 110 is preferably made of polyfluoro-olefin, better known under the brand "TEFLON", product having good stability over time and this on a large scale of

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  temperature. The external pocket 120 can be made of polyvinyl chloride. Advantageously, the protective film 130 is made of polyethylene, a material which has a low coefficient of friction with the steel while remaining practically inert to the stripper.

cited above.

  As previously described, the device

  according to the invention is used in the following manner.

  Figures 2 relate to a cylinder 50

  turning counterclockwise.

  Referring to Figure 2a, the pocket 100 is first fixed longitudinally on the top of the cylinder 50 with the film 130 unwinding backwards where the operator stands. The latter then causes the cylinder 50 to perform three-quarters of a turn as illustrated in FIG. 2b to return the pocket 100 in front of it. It then cuts the rear edge of the film 130 along the circumference

of the cylinder to be cleaned.

  As illustrated in FIG. 2c, the operator must then peel the pocket 100 from the cylinder 50 in order to fold the rear edge of the film 130 against this same cylinder. On this occasion, he checks that the film has wound correctly around of the cylinder along a line

  orthogonal to the axis of rotation, not obliquely.

  It may adjust this position accordingly.

  Then, as illustrated in FIG. 2d, it brings the pocket 100 against the external face of the rear part of the film 130, pocket which it fixes at its front edge on this

  film by means 126 such as an adhesive strip.

  If a longitudinal safety clip 122 is present at

- He -

  the rear opening of the pocket, the operator must remove it, in particular by sliding it sideways while manually retaining the pocket. The operator then completes the installation of the device on the cylinder by closing each lateral edge of the film 130 against the cylinder 50

  using a single piece of adhesive tape if possible.

  With the device thus installed, the operator can lower the counter-cylinder 60 until it comes into contact with the cylinder 50. When the bag 100 passes in the first turn, between the cylinder and the counter-cylinder, the pasty stripper product 10 is then expelled out of the pocket but contained between the film 130 and the cylinder 50. This paste 10 is then distributed in a thin film on the cylindrical surface and in a bead

  150 located at the rear against the cylinder 50 and the counter

  cylinder 60 as illustrated in FIG. 2e.

  Figures 3 illustrate the installation mode of the device for a cylinder 50 rotating in a clockwise direction. The installation mode is symmetrical with respect to a horizontal plane to the mode described above. In FIG. 3a is presented the position of the pocket 100 with the film 130 possibly passing over an attached bar 175 for reasons of convenience. In FIG. 3b is illustrated the position of the pocket 100 when the width

  of the film 130 is adapted to the circumference of the cylinder.

  FIG. 3c shows the lifting movement of the pocket 100 allowing a final correction of the position of the film on the cylinder, then of folding the rear part of the film 130. The fixing of this pocket 100 over the film 130 by means 126 is illustrated

- 12 -

  in 3d figure. FIG. 3e represents the position of the bead relative to the counter-cylinder and to the cylinder when the latter rotates clockwise

of a watch.

  The cylinders are turned at slow speed for a duration varying between 10 minutes and an hour depending on the nature of the residues and the composition of the paste, during which time this pickling paste is continuously kneaded on the surface to be cleaned. This mixing favors the permanent renewal of the active agent in the interstices allowing an optimal action against the residues. Once the actual cleaning phase is complete, the device should be removed from the cylinder 50 without having to come into contact with the pickling product. For this, the operator begins by separating the cylinders and removing the side adhesive strips. Then, as shown in FIG. 4m, the operator turns the cylinder 50 by half a turn. Then, as illustrated in FIG. 4n, it is possible for it to cut the film 130 longitudinally along a line

  diametrically opposite to the bead 150. The counter

  cylinder 60 being raised, the operator turns the cylinder again half a turn forward or backward to

  bring the bead 150 in front of him.

  The operator can then pinch the protective film 130 around the bead 150 to create a longitudinal recovery pocket as shown in Figures 4o and 4p. The removal of this recovery pocket from the cylinder 50 takes the sides

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  adjacent protective film 130 which wipe in passing the cylindrical surface. Once released, this device is carefully rolled up and stored in a container specially designed for transport to a reconditioning station. It is then advisable to wash with large amounts of water, but under low pressure to avoid any splashing, the rest of the stripping product constituting

  a residual film on the cylindrical surface.

  Finally, after this washing, the cylinder can be dried thanks

to a jet of compressed air.

  Still in the spirit of the invention, it is also possible to envisage, with reference to the figures, that the film 230 extends the upper surface of the pocket 200 towards the front relative to the direction of rotation of the cylinder, the opening of the pocket 200 taking place

  always following a line along its rear edge.

  It is therefore imperative that this opening is initially kept closed by the safety cli.p

longitudinal 122.

  This variant of the device is installed on the cylinder in a substantially different manner illustrated by FIGS. 5s to 5w. Indeed, we start in this case by fixing the front edge of the protective film

  230 longitudinally on the cylinder 50 (Figure 5s).

  This fixing can be carried out using an adhesive tape but it is also possible to use a magnetic tape allowing force a slight shift of the position for correction. The cylinder is then rotated by three quarters of a turn or more until the pocket reaches the operator (Figure 5t). This can then adjust the width of the film by cutting so that the pocket

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  overlaps the new front part of the film by a width of approximately 30 cm. Then the operator raises this new front part of the film to fold the pocket against the cylinder (Figure Su) from which he now removes the safety clip. He can then bring the front edge of the film over the pocket and fix on this front edge on the external face of the part of the same film itself located in front of the pocket (Figure 5v). Finally, as before, it sticks adhesive strips along the two lateral edges of the protective film thus isolating the space between the cylinder and the internal face of the film. The counter cylinder is lowered and the actual cleaning phase can begin. The process for removing this device is carried out in a similar manner

  to the process described above (Figure 5w).

  - As will be understood, this device allows the use of strippers or powerful cleanings in a safe way for the operator and the environment. Many improvements can be made to this device and its method of use

in the context of this invention.

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Claims (13)

  1. Device for cleaning the cylinder, characterized in that it comprises a longitudinal pocket (100) substantially as long as the cylinder (50) to be cleaned, containing a pickling mixture (10) which can be opened at will along a line to allow the expulsion of the mixture under the effect of pressure as well as a flexible rectangular protective film (130) inert to the mixture, which film extends the pocket over its entire length and over a greater width at the circumference of the cylinder.   2. Device according to claim 1, characterized in that the opening line of the pocket (100) is initially closed by a longitudinal clip (122) security.   3. Device according to one of claims   above, characterized in that the pasty mixture (10) stripper comprises: - 76 to 98 parts by weight of sulfuric acid of concentration between 80 and 100%, - 3 to 18 parts by weight of chromic acid of concentration between 80 and 100%, - 1 to 15 parts by weight of inert micron powder   with sulfuric and chromic acids.   4. Device according to one of claims   previous, characterized in that the flexible film (130)   protection is made of polyethylene. - 16 -   5. Device according to one of claims   previous, characterized in that the pocket (100) comprises a first internal pocket (110) made of polyfluoro-olefin and containing the pickling paste (10) as well as a second external pocket (120) made of polyvinyl chloride and containing the first pocket (110).   6. Device according to one of claims   previous, characterized in that the protective film (130) extends the pocket (100) backwards with respect to the direction of rotation of the cylinder, and in that the pocket (100) opens under the film (130) along a line on along its rear edge.   7. Device according to claim 6, characterized in that the pocket (100) is provided in its internal face oriented towards the cylinder (50) with means for   temporary fixing (125) of the pocket on the cylinder.   8. Device according to one of claims 1 to   , characterized in that the protective film (230) extends the pocket (200) forwards with respect to the direction of rotation of the cylinder and in that the pocket (200)   opens along a line along its rear edge.   9. A method of cleaning a cylinder using a device according to claim 7, characterized in that it consists in: - fixing the pocket (100) longitudinally on the cylinder, - making the cylinder perform three-quarter turns ) thus partially winding the film (130) on the cylinder (50), - 17 -   - lift the pocket (100) to fold the rear edge of the film (130) against the cylinder (50), - if present, remove the safety clip (122) from the pocket (100), - fix the pocket (100) on the external face of the film (130), - stick the two lateral edges of the protective film (130) on the cylinder (50) by means of adhesive strips, - bring the corresponding counter-cylinder (60) into contact   and rotate the cylinder (50) and the counter   cylinder (60) thus causing the expulsion of the pasty material out of the pocket (100) then the constitution of an active bead (150) of pasty material between the two cylinders (50.60).   10. A method of cleaning a cylinder using a device according to claim 8, characterized in that it consists of: - fixing the front edge of the protective film (230) longitudinally on the cylinder (50), having three quarter turn to the cylinder thus partially winding the film on the cylinder, - lift the front edge of the film (230) to fold the pocket (200) against the cylinder, - if present, remove the safety clip from the pocket, - fix the front edge of the film (230) on the external face of the part of the same film located in front of the pocket (200),   - stick the two lateral edges of the protective film on the cylinder by means of adhesive strips, - bring the corresponding counter-cylinder into contact and rotate the cylinder and the counter-cylinder thus causing the expulsion of the pasty material out - 18 -   of the pocket then the constitution of an active bead of   pasty material between the two cylinders.   11. Method for cleaning a cylinder according to claim 9 or 10, characterized in that the cylinder (50) and the counter-cylinder are rotated together   (60) for a period of between 15 and 30 minutes.   12. Method of cleaning a cylinder according to the   claims 9, 10 or 11, characterized in that, after   having rotated the cylinder (50) and the counter-cylinder (60) together, it consists of: - 8ter the lateral adhesive strips, - rotate the cylinder (50) half a turn backwards, - cut the protective film (130) on one line   diametrically opposite the bead (150), -   15.-rotate the cylinder (50) half a turn forward, - pinch the protective film (130) around the bead (150-) of pasty material to create a recovery pocket, which is gradually drawn out of the cylinder ( 50) by taking the adjacent sections of film of   protection (130) which wipe the cylinder.