EP1238133B1 - Device for treating sheet-like material using pressurized water jets - Google Patents

Abstract

A device for treating sheet-like material using water jets/needles. The device comprises a pressurize water supply body consisting of a feed chamber extending along the entire length of the body and inside which pressurized water is guided through a filter, and a distribution area distributing pressurized water along the entire length of treatment. The distribution area includes a plate (7) which is provided with microperforations, whereby the holes thereof define water needles which are directed against the surface of the material which is to be treated. The invention is characterized in that the microperforations (15) are provided inside inserts (13) which are made of a hard material. The inserts are set inside pre-made hoes (12) in the plate.

Description

Technical area

The present invention relates to an improvement made to facilities for treating sheet materials using water jets under pressure, which act on matter like needles, and which are used in particular for treating nonwoven structures with a view to giving them cohesion and / or modify its appearance.

Such a technique, proposed for decades, as it emerges including US Patents 3,214,819 and 3,485,706, consists in submitting the sheet structure with the action of water jets from one or more ramps successive, the sheet or sheet being supported by a conveyor belt or porous or perforated rotary cylinder, subjected to a suction source allowing the water recovery.

One of the essential elements of such installations is the system for forming jets or needles of water, commonly designated by the expression ^" injector ^" .

The invention relates more particularly to a new type of plate perforated by such injectors and which are one of the essential elements for the formation of water jets or needles.

Previous techniques

The injectors used today have a general structure as illustrated by FIG. 9 of patent US-A-3,508,308 as well as of patent US-A-3,613,999.

More recently, in EP 400249 (corresponding to US 5,054,349), it has been proposed an improved injector which not only allows water to arrive under very high pressure (greater than 100 bar) and whose structure is such that it facilitates installation and removal, for example for cleaning, of the perforated plate through which the microjets are made.

Figure 1 attached illustrates, in general, the structure of a injector.

If we refer to this figure, such an assembly is therefore presented under the shape of a ramp, continuous, extending transversely to the direction of scrolling of the sheet material (F) to be treated, nonwoven for example, and the length is adapted to the width of said material.

This ramp consists of a main body (1), allowing it to withstand any deformation under water pressure, at the top of which is made a chamber (2), generally cylindrical in shape, supplied with water under pressure by a pump (not shown) through a pipe (3).

Inside the chamber (2), is disposed a cartridge (4) constituted by example by a perforated cylinder lined with a filter cloth, which not only plays the role of filter, but also, serves as dispatcher.

The pressurized water introduced inside the chamber (2) then flows through cylindrical holes (5), spaced with a regular pitch over the entire width of the injector, holes whose diameter is generally between 4 mm and 10 mm, the thickness of the wall between two consecutive holes being of the order of 3 to 5 mm.

These cylindrical holes (5), the outlet end of which can optionally be conical in shape, then open into a lower chamber (6) at the base of which is positioned a plate (7) comprising micro-perforations, whose diameter can be between 50 and 500 µm and preferably between 100 and 200 µm, allowing to form jets or needles of water (8) which act directly against the surface of the material (F), nonwoven web for example, at treat.

Maintaining the perforated plate (7) against the main body of the injector is obtained, for example, in accordance with the teachings of EP 400249 by through longitudinal jaws (9) subjected to the action of hydraulic cylinders which make it possible to exert a clamping action by means of a set spreaders and tie rods arranged along the injector.

A seal (not shown) is arranged between the perforated plate (7) and the base of the main body (1).

To date, the perforated plates (7) which allow the production of the jets are all made by drilling or punching fine steel strips stainless.

These strips have a thickness of between 0.6 and 1.2 mm.

Figure 2 is a sectional view of a perforated plate used to date.

In such plates, the capillaries (10) allowing the formation of the jets are, as said previously, obtained by drilling or punching and have a general shape such that they include, if we follow the displacement of the jets, a cylindrical entry zone (11) extended by a divergent wall.

If such plates are satisfactory when the water pressure in the injector is less than 200 bars, however they do not allow working industrially at higher pressures so as to obtain a speed of high fluid up to 300 m / sec.

Indeed, it has been found that the average lifespan of such plates perforated made of stainless steel, did not exceed 24 hours when worked at pressures of 400 bars.

In addition, the drilling and punching techniques used to make the capillaries, do not allow to obtain a perfect surface condition of the internal wall nor to achieve a precise and regular sharp edge at the entrance of each capillary, which, at high fluid speeds, causes a deterioration of the quality of the jets by the formation of turbulence in flow.

Statement of the invention

Now we have found, and this is what is the subject of the present invention, a new type of perforated plate, which solves the above problems and allows a high pressure water supply, up to 400 bar and more, without deterioration of said plate after a period of use which may reach several hundred hours.

Furthermore, the new type of plate according to the invention allows obtain jets with a high speed, up to 300 m / sec or more, very homogeneous and regular over the entire length of the plate.

In addition, it has been found that compared to the previous state, the jets obtained with the plate according to the invention remain consistent over a greater length.

• un corps d'alimentation en eau sous pression comprenant une chambre d'alimentation s'étendant sur toute la longueur dudit corps, et à l'intérieur de laquelle est amenée, au travers d'un filtre, l'eau sous pression ;
• une zone de répartition, distribuant l'eau sous pression sur toute la largeur de traitement comprenant une plaque munie de micro-perforations, dont les trous définissent des aiguilles d'eau dirigées contre la surface de la matière à traiter,

et il se caractérise en ce que les microperforations ou capillaires sont réalisées à l'intérieur d'inserts en matériaux durs, du type zircone, rubis, saphir, céramique, ou autres matériaux de dureté équivalente, enchâssés à l'intérieur de trous préalablement réalisés sur toute l'épaisseur de la plaque.In general, the invention therefore relates to a device called "injector" allowing the treatment of a sheet material (non-woven, textile complex, film, paper ...) by means of jets / needles of water , which includes :

• a pressurized water supply body comprising a supply chamber extending over the entire length of said body, and inside which water under pressure is brought through;
• a distribution zone, distributing the pressurized water over the entire treatment width comprising a plate provided with micro-perforations, the holes of which define needles of water directed against the surface of the material to be treated,

and it is characterized in that the microperforations or capillaries are carried out inside inserts made of hard materials, of the zirconia, ruby, sapphire, ceramic, or other materials of equivalent hardness, embedded inside holes previously made over the entire thickness of the plate.

According to one embodiment, the inserts preferably have a thickness less than the height of the holes made in the plate.

Furthermore, if said inserts can be arranged in a single row on the entire length of the plate, it is possible to arrange them in two rows parallel, the capillaries or microperforations being offset from each other others from one row to the next.

The capillary or microperforation of each insert has a zone cylindrical inlet, whose diameter is between 50 and 500 µm and of preferably 100 and 200 µm as in the case of plate microperforations earlier. This cylindrical part can be extended by a divergent zone in dome or cone shape or by a sudden widening obtained by a zone of outlet of larger diameter than the inlet area.

Advantageously, the thickness of the plate will be between 1 and 3 mm, the machined holes inside which the inserts are embedded, diameter between 0.5 and 2 mm.

The underside of the inserts can be set back from the face bottom of the plate.

Thanks to such a design of the perforated plate, it is possible to generate jets equivalent in number and diameter to those of plates belonging to the art anterior with the advantage of forming each jet in a nozzle whose geometry, the surface condition and hardness are exceptional.

In addition to an extended service life, these new perforated plates with inserts in zirconia, sapphire, ruby or other materials of equivalent hardness, such as ceramic, allow working at high pressures, with very good regularity jets with an increased lifetime for the plates, and, moreover, and surprisingly, such plates lead, in the case where nonwovens are treated, an improvement in the resistance characteristics of the products obtained.

Brief description of the drawings

• comme indiqué précédemment, la figure 1 illustre, de manière schématique, vue en coupe selon son plan de symétrie vertical, la structure d'un injecteur conforme à l'invention, la figure 2 illustrant, quant à elle, également en coupe, la structure des plaques microperforées utilisées dans de tels injecteurs conformes à l'art antérieur ;
• la figure 3 illustre en coupe, fortement agrandie, la structure d'une plaque perforée réalisée conformément à l'invention ;
• les figures 4 et 5 illustrent deux variantes de réalisation d'inserts pouvant être utilisées pour l'obtention d'une plaque perforée conforme à l'invention.

The invention and the advantages which it brings will however be better understood thanks to the exemplary embodiments given below by way of indication, but not limitation, and which are illustrated by the appended diagrams in which:

• as previously indicated, FIG. 1 illustrates, diagrammatically, a view in section along its vertical plane of symmetry, the structure of an injector according to the invention, FIG. 2, for its part, also in section, the structure microperforated plates used in such injectors according to the prior art;
• FIG. 3 illustrates in section, greatly enlarged, the structure of a perforated plate produced in accordance with the invention;
• Figures 4 and 5 illustrate two alternative embodiments of inserts which can be used to obtain a perforated plate according to the invention.

Way of realizing the invention

Referring to FIG. 3 attached, the microperforated plate conforming to the invention therefore consists, like the front plates (7), of a strip of stainless steel having a thickness between 1 and 3 mm, and in which have were machined holes (12), of cylindrical section.

To make the microjets, we embed inside each hole (12), inserts (13) made of zirconia, sapphire, ruby or other hardness materials equivalent.

Such inserts (13) have an outside diameter corresponding to the diameter of the holes (12) and which is therefore between 0.5 to 2 mm.

In this embodiment, the thickness of the inserts is less than the thickness of the plate (7) so that they are set back by relative to the underside (14) of the plate when said inserts (13) have been put in place.

Each insert has on its thickness a capillary or microperforation (15) having a diameter between 100 and 200 µm extended at its base by a divergent (16) in the shape of a dome or cone.

The presence of such divergences (16), as well as the fact that the inserts (13) are set back from the underside (14) of the plate (7), cause the capillary (15) therefore opens into a vacuum inside each hole (12).

Surprisingly, such a structure has the consequence of causing better jet formation.

To illustrate the advantages provided by the invention, comparative tests were carried out on a machine of the “Jetlace 2000” type of the Applicant equipped injectors produced according to the prior art as illustrated in FIG. 2, and injectors equipped with a perforated plate (7) produced in accordance with the invention for a second series of tests carried out under the same conditions of water pressure.

• diamètre de la chambre supérieure (4) :   50 mm
• diamètre des conduits (5) :   6 mm
• distance entraxe de deux conduits (5) consécutifs :   10 mm
• hauteur des conduits (5)   35 mm
• hauteur de la chambre inférieure (6) :   10 mm

In these comparative tests, the injectors which have a structure as illustrated in FIG. 1, have the following characteristics:

• diameter of the upper chamber (4): 50 mm
• diameter of the conduits (5): 6 mm
• distance between centers of two consecutive conduits (5): 10 mm
• duct height (5) 35 mm
• height of lower chamber (6): 10 mm

In the first series of tests (tests no. 1), the microperforated plate produced in accordance with the prior art comprises two rows of microperforations of 120 µm spaced 1.2 mm apart in each row and being shifted from one row to the next, each row having 833 microperforations thus leading to a plate which, per meter, comprises 1666 pinholes.

The thickness of the stainless steel strip in which the plate is 1 mm.

The other series of tests (tests no. 2) is carried out using compliant plates to the invention produced in a strip, also made of stainless steel, but having a thickness of 2 mm.

In such a plate, the microperforations are carried out in inserts (13) encased in holes (12) having a diameter of 0.7 mm.

Each insert (13) has a thickness of 0.2 mm and has in the part central a capillary (15) also having a diameter of 120 µm extended by a divergent (16).

These inserts are made of zirconia and are, as for the plate microperforated produced in accordance with the prior art, arranged in two rows, each row also comprising 833 holes each having a diameter of 120 µm and spaced, in each row, by 1.2 mm, thus leading to a plate which also has 1666 holes per meter.

In the two concrete examples which follow, essay no. 1 is made from of a conventional perforated plate, and test no. 2 from a plate perforated with zirconia inserts according to the invention.

Example 1

A nonwoven based on viscose fibers 1.7 dtex / 40 mm, weighing 150 g / m ^2, is treated under the above conditions.

The processing conditions and the characteristics of the product obtained are shown in the table below. Pressure bars Machine direction resistance N / 50 mm Cross direction resistance N / 50 mm TEST 1 200 319 87 TEST 2 200 367 100

Example 2

A second series of tests is carried out, but on a non-woven fabric based on 1.7 dtex / 38 mm polyester fibers, weighing 330 g / m ² .

The treatment conditions (pressure) and characteristics of the products obtained are grouped in the table below. Pressure bars Machine direction resistance N / 50 mm Cross direction resistance N / 50 mm TEST 1 350 659 1670 TEST 2 350 720 1837

We note that in the two series of comparative tests, we obtain a improved resistance of the treated product, both in the machine direction and in the cross direction with the plates produced in accordance with the invention.

Furthermore, in use, it has been observed that the plates produced according to the invention withstood much better over time than anterior plates.

In addition, it was found that the product obtained in accordance with Example 1, and which was therefore based on viscose fibers, presented, after treatment, a state of much more uniform surface when treated in accordance with the invention, while traces of jets appear on the product produced from of a conventional plate.

Figures 4 and 5 illustrate two embodiments which allow facilitate the replacement of an insert (13) which could be damaged during of use and which also show variations in the shape of the capillaries.

Thus, in the embodiment illustrated in FIG. 4, the insert (13) is mounted not directly inside the duct (12), but via an intermediate support (20), embedded in the conduit (12) which therefore has a diameter greater than that illustrated in Figure 3.

This support has a lower hardness than that of the insert (13) and can be produced Stainless steel.

In this embodiment, the capillary (15) is cylindrical over its entire length and opens into a conduit (21) of greater diameter causing a abrupt enlargement.

In the variant illustrated in FIG. 4, the insert (13), also produced in zirconia, has at its upper part a flange (22) which bears on the face top of the plate (7).

The capillary also consists of an extended cylindrical conduit (15) by a zone (23) of larger diameter, also causing widening sudden.

Such a design can facilitate the removal of an insert for its replacement.

Finally, if in the examples illustrated, the inserts are set back by compared to the underside of the plate it could be considered that they arrive at the level of the latter.

Of course, the invention is not limited to the embodiments described previously, but it covers all variants made in the same mind.

Claims (7)

1. A device for treating sheet material by means of water jets/needles, comprising :

   a body for supplying pressurized water comprising a feed chamber extending over the entire length of said body, and inside which the pressurized water is taken through a filter ;

   a distribution region, distributing the pressurized water over the entire treatment width, comprising a plate (7) fitted with microperforations, the holes of which define water needles directed against the surface of the material to be treated,

   characterized in that the microperforations (15) are produced inside inserts (13) made of hard materials, set inside holes (12) previously made over the entire thickness of the plate.
2. The device as claimed in claim 1, characterized in that the inserts are made of zirconia, ruby, sapphire, ceramic or other materials of equivalent hardness.
3. The device as claimed in either of claims 1 and 2, characterized in that the inserts (13) have a thickness less than the depth of the holes (12) made in the plate (7).
4. The device as claimed in one of claims 1 to 3, characterized in that the capillary or microperforation of each insert (13) has a cylindrical inlet region (15), this cylindrical part being extended by a divergent region (16) in the shape of a dome or a cone.
5. The device as claimed in one of claims 1 to 4, characterized in that the machined holes (12), inside which the inserts (13) are set, have a diameter of between 0.5 and 2 mm, the capillary or microperforation of each insert having a diameter of between 50 and 500 µm and preferably between 100 and 200 µm.
6. The device as claimed in one of claims 1 to 4, characterized in that the insert (13) is mounted on an intermediate support (20) set into the hole (12).
7. Device according to one of Claims 1, 2, 3, 5 and 6, characterized in that the cylindrical duct (15) opens out into a duct (21-23) of greater diameter, leading to a sudden broadening.

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