FR2625937A1 - METHOD AND DEVICE FOR PUNCHING A SHEET PRODUCT, AND PERFORATED PRODUCT THUS OBTAINED - Google Patents

Abstract

The invention relates to a fixed injector 3, 8, 9 sending pressurized water to work a sheet 1 of non-woven material, or the like. The micro-perforated plate 5 allows the injector 3, 8, 9 to send water needles 7 on the sheet 1. It is possible to interpose a perforated cylinder 14 which does not touch the gap sheet 17. Application: micro- perforation by points or slits, of various materials, including plastic in flexible sheets.

Description

The present invention relates to a

  universal, to make a sheet that is complete

  partially punched, that is to say, in particular a sheet pierced with multiple perforations, or a sheet having, at the end of the operation, a drawing with

hollow or raised patterns.

  It is understood that this new process

  calf may be used on a sheet of material

  conch, which may be, in particular, a paper, a cardboard, a nonwoven fabric, a film, or a plate of

  plastic material, or even a sheet of wood or

  plate. The invention also relates to

  new industrial products obtained by this method.

  of, and possessing original characteristics that it does not

  is not possible to obtain with traditional methods

the known ones.

  It is known to manufacture nonwoven fabrics having perforations or having

  areas of reduced density fiber, especially for

  applications in medical or hospital fields, wiping, filtration, envelopes for tea bags etc ... For this, it is known, for example in the French patent 2,068,676, to circulate a- web of fibers on the porous web of a carrier,

  the sheet to be treated passing under a perforated rotary cylinder

  inside which is placed a hydraulic injector

  that, in the form of a transverse bar,

  dirty fixed. This injector projects under pressure a curtain

  of continuous water, some of which passes through the cylinder holes.

  perforated, creating jets of water whose size

  sion corresponds to that of the perforations of the cylinder. These jets of water cross the fiber web reproducing on it the shape of the holes of the cylinder before being collected by a suction box located under the canvas

  of the conveyor, below the rotating cylinder.

  Such a known device presents

  great disadvantages. Indeed, the use of an injection

  providing a continuous layer of water throughout the entire

  of the cylinder results in the issuance of a

  considerable water bit inside it.

  because the perforated parts of the cylinder are

  present only a small part of the surface of it,

  As a result, we are quickly confronted with a

  practically insoluble problem, that of eliminating

  inside the cylinder, water reflected from

the solid parts.

  In order to limit the problem,

  reduces the amount of water emitted by the injection

  to reduce the thickness of the water curtain,

  as well as the pressure of the water, which

  this obtaining, outside the cylinder, jets of water that do not have sufficient kinetic energy to perforate plastic film-like materials, fabrics,

even thick paper.

The water that bounces on the parts

  full of the cylinder along the same disturbing generator.

  also the cohesion of the curtain of water and

  the kinetic energy of the jets of water emitted by

  the cylinder. In fact, water tends to fall back

  random pattern in the cylinder after bouncing. This results in an uncontrolled accumulation of water along the generatrix of the cylinder located to the right of the curtain of water. This excess water plays the role of

  damper to the water emitted by the injector who sees

  if his kinetic energy is reduced to a level

  is insufficient to ensure uniform marking of the sheet at this location. The result is, on the sheet to be treated, the appearance of areas having a faded appearance

  whose drawing or perforation is poorly defined.

The present invention aims

  to avoid these drawbacks, by making a practical machine

  universal for the manufacture of paper, nonwovens, textiles or plastic films

  perforated or having recessed or raised patterns.

  A device according to the invention comprises a support fabric for the sheet material to be treated

  to be treated that advances with the material under a cylinder

  drilled, within which is disposed an injection

  transverse-oriented water jet to project pressurized water through the cylinder perforations

  towards the leaf to be treated, and is characterized

  in that the hydraulic injector comprises, on the one hand, a high-pressure water inlet chamber which delivers the water against a perforated plate whose holes define water needles then directed in front of the holes of the cylinder, on the other hand, under the sheet to be treated, a

  suction box for water having passed through said sheet

the.

According to another characteristic

  that of the invention, the needles are arranged opposite the holes of the cylinder, shifted along one or more generatrices thereof, so as to be the most spaced from each other, firstly, to avoid, as far as possible, parasitic phenomena due to the reflection of the water on the solid parts of the cylinder, other

on the other hand, to limit the flow of water.

According to another characteristic

  that of the invention, the diameter of the holes of the plate

  drilled is between 50 and 500 microns. In the case

  products which must have a perforation of sufficient size

  than the nominal size of the water needles, it

  a perforated plate pierced with holes

  following several distinct generators, the holes

  of the plate being always located opposite those of the

  liner, so that the water emitted by the injector covers

  fully the width of the cylinder holes.

According to another characteristic

  that of the invention, the injector comprises a device for

  maintaining the perforated plate, making it possible to remove

  the latter of the body of the injector: the plate

  drilled is strongly applied against the main body of the injector through the action of hydraulic cylinders which

  pull the plate upwards through a

  seems of pedals and tie rods arranged along the injector. A seal, located between the perforated plate and

  the main injector body makes it possible to seal

  of the set .. Just relieve the oil pressure

  in the hydraulic cylinders, to release the clamping jaws of the perforated plate, which can then be extracted very easily, by pulling it in the longitudinal direction of the injector, that is to say transversely to the direction of advancement of the sheet material. According to another characteristic of the invention, the water pressure in the main body of the injector is between 2 and 500 bar depending on whether the

  material to be treated is more or less thick and must be

  drilled, or simply marked with a jet of water.

  According to another characteristic of the invention, the perforated cylinder may be in contact with or be detached from the sheet to be treated so that its speed of rotation can be independent of the speed of movement of the sheet, the rotation being able to possibly take place in the opposite direction to the scrolling of the sheet. The fact of being able to modify the speed of rotation of the cylinder with respect to the sheet results in a variable number of holes in the cylinder passing to the right of the water needles emitted by the injector.

  hydraulic system, which results in obtaining a true

  hydraulic shutter table with variable speed and the pos-

  the ability to obtain, from a cylinder having a predetermined number of holes per cm, a sheet having a

  a totally different number of holes per cm, and in particular

  to bind, micro-holes, which is absolutely impossible to achieve with conventional methods, when

  the speeds of the cylinder and of the sheet to be treated are identical.

  ticks. The perforated cylinder can be of any type, stainless steel, bronze or nickel. This enumeration is not limiting: it can also be of the same type, for example, as the cylinders

  well-known serigraphs used in textile printing.

  tile or deposition of plastic material in relief on

  floor coverings: the only limit is its mechanical resistance

picnic

  the action of water needles emitted by the injection

hydraulic power.

  The attached drawing, given by way of non-limiting example, will make it possible to better understand the characteristics of the invention, and the advantages it

is likely to procure.

  FIG. 1 is a view of an injector according to the invention, comprising a perforated plate with

  holes arranged along three generatrices of the cylinder.

  1 Figure 2 shows an injector se-

  according to the invention, disposed inside a hollow cylinder

  perforated with rectangular holes arranged in helicoid-

  of, so that the needles emitted by the injector are located alternately in front of a solid part and

a perforated part of the cylinder.

  Figure 3 shows a plate

  drilled with three rows of staggered holes

  to others, so as to completely cover the

perforated parts of the cylinder.

  FIG. 1 shows a sheet 1, for example a nonwoven fabric, which advances in the longitudinal direction represented by the arrow 2. Transversally, and above the sheet 1, is the fixed elongated body 3 of an injector in which

  is defined a water chamber 4. The bottom bottom of this

  it consists of a plate 5, on which are

  made of micro-perforations 6, which will define, each

  ne, a water needle 7. Two longitudinal jaws 8 and 9 are subjected to the action of hydraulic cylinders such as.

  to pinch and tighten the longitudinal edges (perpendicular

  2), the plate 5 against the body 3 of the injector.This clamping ensures the sealing of the assembly of

  the plate 5 against the injector body 3, when the assembly

  ble is in use. On the other hand, for cleaning and

  maintenance, simply release the cylinders 10, to extract

  Conveniently the plate 5, pulling it transversely, as indicated by the double arrow 11. This chamber

  water 4 is, for example, surmounted by a feed chamber.

  water supply 12, with which it shares with

wide openings 13.

In the example of Figure 2, 1 '

  hydraulic injector 3 - 5 - 8 - 9 is mounted at

  Xe inside a rotating cylinder 14, on the thin wall 15 which are distributed holes 16

Following an important characteristic

  of the invention, the wall 15 of the cylinder 14 can

  to be at a distance 17 above the upper surface

  of the sheet 1. Thus, is the tangential speed of the rotary cylinder 14 (arrow 18) independent?

  the speed of advance of the sheet 1 (arrow 2).

Example 1

  A non-woven sheet of 18 g / m 2 obtained by the so-called wet method is supported by a knit-type bronze fabric having 32 threads in the warp direction and 27 threads in the weft direction. is subjected to the action of the device shown in the figures

2 and 3.

  The perforated cylinder 14 has holes 16 of

  rectangular section of 0,8 mm in the axial direction (

  19), and 1.3 mm in the tangential direction (arrow 20), the distance between these holes being 0.8 mm in both directions. The thickness of the cylinder is 0.4 mm and the section of the orifices is identical inside and outside

of the cylinder.

  The hydraulic injector comprises a perforated plate 0.3 mm thick having three rows of

  0.28 mm in diameter spaced 1.6 mm (axis to axis)

  generator, and 1 mm between the generators

(see Figure 3).

  The pressure of the water in the injector is 3.5 bars (chambers 4 and 12). The cylinder is maintained at 0.5 mm above the sheet 1 and its tangential speed of rotation (arrow 18) is equal to the speed of advance

from there sheet 1 (arrow 2).

  The treatment of sheet 1 carried out in these conditions

  ditions makes it possible to obtain a sheet exhibiting

  absolutely perfect and uniform sin corresponding to

  rations of the cylinder 14 over the entire surface of the sheet 1.

  A similar treatment, performed on the same sheet 1,

  but replacing the needle injector 7 with an injection

  "curtain" type unit delivering a continuous curtain of water

  thickness of 0.12 mm across the entire width of the sheet

  it would not be possible to obtain good results,

  many parts of the sheet 1 having then a

faded pect.

  Example 2 A plastic sheet 30 microns thick

  is subject to the action of the preceding device.

  The same cylinder 14 as before is used.

  The sheet 1 is placed on a support cloth made of stainless steel of the "plain" type, comprising 7 threads per cm,

in the warp and weft directions.

  The perforated plate 5 of the injector comprises a single row of holes 6, 0.12 mm in diameter, spaced apart

each other by 1.6 mm.

  The perforated plate 5 is positioned such that

  that the water needles 7 are located approximately

  in the middle of the orifices 16 of the perforated cylinder 14.

  The pressure of the water in the injector is 150 bar and the

  treatment speed of 25 meters / min.

  The cylinder is 1 mm above the canvas (interval 17), and its tangettielle.de rotation speed

  (arrow 18) is equal to the speed of advance of the sheet

the 1 and its canvas (arrow 2).

  The plastic sheet 1 is perforated in the form of fine rectangular slits, 0.8 mm in length and

of unmeasurable width.

  Resistance in the transverse direction of the sheet

  the 1 is considerably reduced, and its porosity is greatly increased. After perforation, the sheet 1 sBmiee to a jet

water is no longer waterproof.

Example 3

  The same sheet 1 is subjected to a similar treatment

  milaire.The only difference with the previous treatment

  is the speed of rotation of the cylinder 14 which gives a

  tangential pitch (arrow 18) of 120 meters per minute (or about five times the speed of

sheet 1 (arrow 2).

  The other conditions remain unchanged. The plastic sheet 1 is now perforated by a multitude of small holes whose dimensions do not

are not measurable.

  The air permeability of the sheet is excellent

  slow, and its transverse resistance is little affected.

  Leaf. subject to a water jet also remains impervious

  corn. Finally, the plastic film has lost its "sounding" characteristic.

Claims (8)

  1 - Process for the manufacture of a   sheet (1) of a material carried by a conveyor belt   porous advancing under a hydraulic injector trans-   fixed valve (3), characterized in that the hydraulic injector   lique (3) delivers water needles (7) distinct from each other, these needles (7) being obtained by means of a perforated plate (5), pierced with holes (6) distinct from each other.   2 - Process according to claim 1, characterized in that the hydraulic injector is fed with water at a pressure of between 2 and 500 bars.   3 - Process according to any one of   preceding claims, characterized in that between the   water needles (7) of the injector and the sheet (1) to   to treat, one interposes a movable perforated organ.   4 - Process according to revendiaction 3,   characterized in that the perforated member is a rotatable cylinder   tif (14) disposed around the injector, and on the wall   (15) which are distributed holes (16).   - Method according to claim 4, characterized in that between the perforated rotary cylinder (14) and the sheet to be treated (1) is left a free gap (17), so that the tangential speed (arrow (18) of the cylinder (14) has a value independent of the value of   the speed of advance of the sheet (1) (arrow (2).   6 - Device for implementing the   process according to any one of claims 1 to 5,   characterized in that, under the body (3) of the injector,   is clamped by longitudinal jaws (8) and (9), a flat   that (5), provided with micro-perforations (6), surmounted by   a water chamber (4) for creating water needles (7).   7 - Device according to Claim 6,   characterized in that the clamping of the plate (5) is   by hydraulic cylinders (10), it suffices to re-   to release, to extract the plate (5) by pulling it transversely   dirty on the machine (arrow (11).   8 - Device according to any one   claims 6 and 7, characterized in that the   cro-perforations (6) are distributed along the plate   (5) following several parallel rows where they are de-   stalled from one row to another. 9 - Leaf with intaglio patterns and   relief, characterized in that it is obtained by half   the process according to any one of the dications 1 to 5   10 - Sheet provided with perforations,   as obtained by the implementation of the   process according to any one of claims 1 to 5.