EP1190132B1 - Device for treating sheet materials using pressurised water jets - Google Patents

Abstract

A mechanism for the treatment of materials by pressurized water jets includes a body (1) for supplying water under pressure which includes a feeding chamber (2) extending over the whole length of the body, and wherein water under pressure is fed to the feeding chamber through a filter (4). The body also includes a distributing zone for distributing water under pressure over a whole treatment length against a plate (7) provided with micro-perforations which define water needles (8) directed against the surface (S) of the material to be treated. The material is supported by a carriage element subjected to a suction source eliminating the treatment water. Further, water transfer from the intake chamber (2) to the perforated plate (7), is done through a channel (22) with a rectangular cross-section extending over the whole length of the injector, from the periphery of the feeding chamber (2) up to the surface or the perforated plate (7), wherein the spacing between the side walls (21) of the channel and the height thereof produces a unidirectional and stable stream of water without turbulence.

Description

Technical area

The present invention relates to an improvement made to the installations for treating sheet materials with water jets under pressure, which act on the structure in the manner of needles, used especially for treating non-woven structures in order to give them cohesion and / or change its appearance.

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

One of the essential elements of such facilities is the training system jets or water needles, commonly referred to as "injector".

The invention relates more particularly to a new type of injector.

Previous techniques

Injectors used today and which, concretely, can be realized in accordance with the teachings of Figure 42 of US-A-3,485,706 and corresponding passages in the description of this document, as well as concrete achievements much more detailed notably from the US patent 3,613,999 and EP 400249 (corresponding to US 5,054,349), the latter document describing a type of injector that not only allows an arrival very high pressure water (greater than 100 bar) has a structure such that it allows to set up and remove the perforated plate through which make the microjets easily.

With reference to the appended FIG. 1, in general, such injectors are therefore in the form of a ramp, continuous, extending transversely to the direction of travel of the sheet material (F) to treated, for example, non-woven, and whose length is adapted to the width of said material. This ramp can either consist of a single elementary module or a plurality of modules juxtaposed to each other.

Such a ramp consists of a main body (1), making it possible to withstand any deformation under the pressure of the water, at the top of which is made a chamber (2), generally of cylindrical shape, fed with water under pressure through a pipe (3) fed by a pump (no shown).

Inside the chamber (2) is arranged a cartridge (4) constituted by example by a perforated cylinder lined with a filter cloth, which not only plays the filter role, but also serves as a 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, a hole 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 bores (5), whose exit end can possibly be of conical shape, then open into a lower chamber (6) at the base of which is positioned a plate (7) provided with micro-perforations, of which the diameter may be between 50 and 500 μm and preferably between 100 and 200 μm, for forming jets of water or needles (8) which act directly against the surface of the material (F), nonwoven web for example, to treat.

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

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

Such a system for dispensing water under pressure against the micro-perforated plate intended to form the water needles, and which therefore uses holes (5) which open into a lower chamber (6), distributes the water correctly over the entire length of the injector, the same flow of water passing through through each orifice.

However, it has been found that such a solution, particularly in the case of treatment of non-woven webs, could lead to defects in the product treated when the water pressure in the injector exceeded 50 bar.

Figure 2 schematically illustrates the reasons for such defects.

Referring to this figure, it was found that when increasing the water supply pressure inside the cylindrical bore (2), which is imperative when one wishes to increase the speeds of production and / or to treat heavy products, that there were turbulence zones in the chamber (6) at the level of the zones (10) immediately below the walls separating two consecutive bores (5). This turbulence is transmitted to jets of water, which causes a significant and rapid loss of their energy, the jets (J1) becoming diffuse and whitish below said zones of turbulence, then that, under the bores (5), the flow of the jets (J2) remains unidirectional, stable and without turbulence.

During the treatment of the nonwoven webs, such a disparity of flow is immediately affects the binding efficiency of the fibers and leads to produces a heterogeneity of the entanglement of the fibers with in particular a density variation.

As a result, as shown schematically in Figure 1, we obtain on the finished product strips (B) of low density and very irregular surface, which exactly coincide with the turbulent flow zones between the holes.

Presentation of the invention

Now it has been found, and this is the object of the present invention, a improvement brought to such a type of injector, which allows to solve this problem and allows a high-pressure water supply that can reach up to 400 bar and more, which allows for a flow of water under pressure, stable, without turbulence between the water supply chamber under pressure and the piercing plate forming jets / treatment needles, said jets being perfectly homogeneous and all having an identical action on the product treat.

• d'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 contre une plaque munie de micro-perforations, dont les trous définissent des aiguilles d'eau dirigées contre la surface de la matière à traiter, matière supportée par un élément transporteur (tambour ou tapis), soumis à une source d'aspiration permettant l'élimination de l'eau de traitement, et il se caractérise en ce que le transfert de l'eau depuis la chambre d'alimentation jusqu'à la plaque perforée, est réalisé par l'intermédiaire d'un canal de section rectangulaire s'étendant sur toute la longueur de l'injecteur, depuis la périphérie de la chambre d'alimentation jusqu'à la surface de la plaque perforée, l'écartement entre les parois latérales de ce canal ainsi que sa hauteur produisant un écoulement d'eau unidirectionnel, stable et sans turbulence.

In general, the injector according to the invention thus allowing the treatment of a sheet material (nonwoven fabric, textile complex, film, paper ...) by means of jets / water needles is composed :

• a pressurized water supply body comprising a supply chamber extending over the entire length of said body, and inside which is supplied, through a filter, water under pressure;
• a distribution zone, distributing water under pressure over the entire treatment width against a plate provided with micro-perforations, the holes of which define water needles directed against the surface of the material to be treated, material supported by an element carrier (drum or belt), subjected to a suction source for the removal of process water, and characterized in that the transfer of water from the feed chamber to the perforated plate , is realized through a channel of rectangular section extending over the entire length of the injector, from the periphery of the feed chamber to the surface of the perforated plate, the spacing between the side walls of this channel and its height producing a flow unidirectional water, stable and without turbulence.

To obtain such a laminar flow of water under pressure, the space between the two side walls defining the distribution channel, is advantageously between 2 mm and at most 10 mm, the height of the walls being, for its part, between 5 mm and 100 mm, the jets produced through micro-perforations having, thanks to such a structure, an identical energy output and this, over the entire treatment width.

Brief description of the drawings

• comme indiqué précédemment, la figure 1 illustre, de manière schématique, vu en coupe selon son plan de symétrie vertical, la structure d'un injecteur conforme à l'art antérieur, la figure 2 illustrant, quant à elle, de manière schématique, les turbulences et formations de jets irréguliers que cela entraíne lorsque l'on augmente la pression de l'eau introduite dans le corps de l'injecteur ;
• la figure 3 illustre également, de manière schématique, en perspective et en coupe selon son plan de symétrie vertical, la structure générale d'un injecteur conçu conformément à l'invention et ;
• la figure 4 est une vue schématique de l'écoulement de l'eau sous pression à l'intérieur d'un injecteur réalisé conformément à l'invention.

The invention and the advantages it brings will however be better understood thanks to the embodiment given hereinafter by way of indication, but not limiting, and which is illustrated by the appended diagrams in which:

• as indicated above, FIG. 1 schematically illustrates, in section along its plane of vertical symmetry, the structure of an injector according to the prior art, FIG. 2 schematically illustrating the irregular turbulence and jets formation that results when increasing the pressure of the water introduced into the body of the injector;
• Figure 3 also schematically illustrates in perspective and in section along its vertical plane of symmetry, the general structure of an injector designed according to the invention and;
• Figure 4 is a schematic view of the flow of water under pressure inside an injector made according to the invention.

Way of realizing the invention

Referring to the appended FIG. 3, and using the same references for common elements than those used to describe the state of the art illustrated in FIG. 1, the injector according to the invention consists, in a manner similar to this state of the art, of a main body (1) made of steel, having a length of 3500 mm, a total width of 200 mm, and a height of 200 mm.

In the upper part of this body is made a cylindrical chamber (2) having a diameter of 70 mm. This room is supplied with pressurized water. through a pipe (3).

In the annexed figure, the water supply is illustrated as being done laterally, but it could be done from the top of the body or the back.

Inside the bore (2) is arranged a cartridge (4) constituted by a perforated cylinder coated with a filter cloth.

At the base (20) of this upper body, is fixed, for example by means of jaws side plates (9), a micro-perforated plate (7) produced, in the present case, by a steel strip 1 mm thick, 25 mm wide and with at least a row of orifices, the diameter of which is preferably between 100 and 200 μm and which are spaced from a distance between centers in general between 0.6 and 1.2 mm.

Sealing means, joints (23) for example, are of course provided between the base (20) of the upper body and the surface of the micro-perforated plate (7).

According to the invention, the transfer of water under pressure to the plate (7) formation of water jets, is obtained through a channel (22) extending from the periphery of the chamber (2) to the surface of the micro-perforated plate (7). This split channel consists of two opposite parallel walls (21) spaced apart each other by a distance of between 1 mm and a maximum of 10 mm, the height being, meanwhile, between 5 mm and 100 mm. This split channel is closed laterally.

Thanks to this new embodiment, and as illustrated by the FIG. 4 gives a laminar flow of water under pressure, without any turbulence as shown in Figure 4, the jets (8) produced through the orifices of the plate (7) all having the same energy.

To illustrate the advantages provided by the invention, comparative tests were made on a machine of the type "Jetlace 2000" of the Applicant equipped injectors made according to the prior art as illustrated in FIG. 1 for a series of of tests, and injectors made according to the invention for a second series of tests carried out under the same conditions of water pressure.

In these comparative tests, the injectors of the prior art as illustrated in FIG. 1, have the following characteristics: diameter of the upper chamber (4) 50 mm diameter of the ducts (5) 6 mm distance between two consecutive ducts (5) 10 mm height of ducts (5) 35 mm height of the lower chamber (6) 10 mm micro-perforated plate having a single row of micro-perforations of 120 μm, spaced from each other by 0.6 mm

The other series of tests is carried out on the same machine, with injectors made according to the invention, whose upper chamber has the same diameter than the conventional injectors, and which, compared to these, has a split channel (22) 36 mm high, extending from the intake chamber (4) up to the micro-perforated plate (7), and whose walls parallel are spaced from each other by 3 mm.

The micro-perforated plate is also constituted by a plate comprising 120 μm orifices, spaced from each other by 0.6 mm.

In these comparative tests, a nonwoven web weighing 250 g / m ² based on polyester fibers having a titer of 1.7 dtex and a width of 38 mm is treated.

This veil is subjected to the action of two injectors acting successively against both sides of the veil.

Water is fed inside the upper chamber of each type injector by gradually increasing the supply pressure.

It can be seen that, for the same speed of passage of the nonwoven web in below the treatment jets, that up to a pressure of the order of 50 bars, the products obtained with each type of injector have good homogeneity and comparable mechanical characteristics.

In contrast, above 50 bar, using a conventional injector such as shown in FIG. 1, there are defects in the bonding of the product formed, defects which increase when pressure is increased, and lead to the formation of irregular parallel strips, as shown in Figure 1.

On the other hand, the injector according to the invention makes it possible to obtain a tablecloth perfectly bonded, without apparent defect, for a supply pressure reach 400 bars.

Consequently, it can be envisaged, thanks to the device according to invention, to increase production speeds without damaging the characteristics of the product, ie to treat much thicker even different types of complexes for which conventional injectors do not can not be used.

Claims (2)

1. An injector for the treatment of sheet materials by means of water jets/needles, comprising :

   a body (1) for supplying pressurized water, comprising a feed chamber (2) which extends over the entire length of said body and inside which the pressurized water is taken through a filter (4) ;

   a distribution region, distributing the pressurized water over the entire treatment width against a plate (7) provided with microperforations, the holes of which define water needles (8) directed against the surface of the material (S) to be treated, said material being supported by a transporter element subjected to a suction source allowing the treatment water to be removed,

   characterized in that the water is transferred from the intake chamber (2) to the perforated plate (7) via a channel (22) of rectangular cross section extending over the entire length of the injector, from the periphery of the feed chamber (2) to the surface of the perforated plate (7), the separation between the side walls (21) of this channel and its height producing a unidirectional, stable and turbulence-free flow of water.
2. The injector as claimed in claim 1, characterized in that the space between the two side walls (21) defining the distribution channel (22) is between 1 mm and at most 10 mm, the height of the walls being between 5 mm and 100 mm.

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