EP0196953B1 - Respiratory mask and method of manufacturing it - Google Patents

Description

The invention relates to a new disposable respiratory mask, the filter element of which consists of a granular material, for example granular activated carbon.

It also targets its manufacturing process.

FR-A-2 414 941 describes a disposable respiratory mask comprising a shell made of heat-shrinkable materials comprising an outer ply having a plurality of cells projecting from its anterior face of said outer ply and occupying almost all of its surface, each of said cells defining an enclosure containing a grainy filter material, in particular activated carbon, highly compressed, said cells being closed by an inner ply applied to the outer ply during a thermal welding operation, such a mask has the drawback that air crossing the mask with a tendency to pass through the areas where the pressure drop is the lowest, that is to say around the cells in the areas where the two plies are directly in contact as well as at the base alveoli on the periphery thereof so that the air passing through the mask has little or no contact with the granular material. The filtration effect is therefore weak.

The present invention proposes to provide a mask having an improved filtration effect as a result of a channeling of the air entering the mass of the granular filtering material contained in each cell.

The characteristics of the mask according to the invention and of its manufacturing process are indicated in the claims.

• - La figure 1 est une vue en perspective d'un masque selon l'invention;
• - La figure 2 est une vue éclatée montrant les différents éléments.

Other features and advantages of the invention will appear on reading the following description made with reference to the appended drawings in which:

• - Figure 1 is a perspective view of a mask according to the invention;
• - Figure 2 is an exploded view showing the different elements.

As can be seen in FIG. 1, the mask is in the form of a shell C, the periphery of which closely follows the facies of the user by means of a flange made of two elements B1-B2 assembled behind the neck. thanks to two complementary elements V1-V2 formed by a hook-and-loop tape like the one sold under the brand VELCRO.

According to the invention, this shell C is provided with a plurality of cells A1-A6 projecting from its anterior face, each cell being truncated pyramid. or tapered.

Advantageously, these cells are arranged radiating in the direction of the most anterior part of the snout - either that they meet at this point, or that they end in a circular alveolus or even in a central valve S of the outlet of the expired air.

Each cell is filled with grain filtering material (activated carbon for example) compressed by heat shrinking the material constituting the shell C.

As can be seen in FIG. 2, this shell C consists of a chamber initially made of three flat sheets: an outer sheet C1 made of nonwoven of retractable fibers such as polyvinyl fibers permeable to the fluid to be treated, an intermediate plate P made of a semi-rigid PVC film impermeable to the fluid to be treated and an inner web C2 of food-grade anti-allergic polyvinyl permeable to the fluid to be treated.

The outer ply C1 is preformed with cells (Al -A6) as has just been said.

The intermediate plate P is cut out of holes T1 to T6 (possibly T7) corresponding to the shape, number and arrangement of the cells of the sheet C1, however, the dimensions of these holes are smaller than those of the corresponding cells for reasons which will be explained more far.

The sheet C2 is not pierced.

The C1 sheet being placed flat, cells below, it is completely filled with activated carbon (or any similar filter material); the intermediate plate P is placed above, making its holes coincide with the cells then the sheet C2; a flat weld is carried out to close the cells.

Because the T1-T6 openings are weaker than the base of these cells, the air entering this zone is diverted towards the activated carbon before being able to reach the interior of the mask. After cutting the vee, preferably two in number at the upper and lower ends respectively, to facilitate folding, the process is carried out and the appropriate welds.

The calorific contribution necessary for this shaping and the subjugation between them of the different layers, produces at the same time the retraction of the three layers, which has the effect of compressing the activated carbon between the layer C1 limiting the alveoli and the closing tablecloth C2.

Optionally the central cell can be replaced by an exhalation valve 3 which is then assembled in a conventional manner.

• - l'anhydride sulfureux et sulfurique
• - les oxydes d'azote
• - les acides halogénés: chlorhydrique, bromhydrique, iodhydrique
• - les acices hydrogénés: hydrogène sulfuré, mercaptans, et en général partout où des poussières non fibrogènes constituent une gêne pour l'usager avec émission de vapeurs organiques ou acides et en particulier contre les vapeurs de poly- uréthanes et d'isocyanates (lorsque leur concentration est inférieure à 0,2 ppm.).

Filled with activated carbon, the mask thus obtained can be used inter alia for protection against non-fibrogenic dust without particular toxicity and against organic vapors whose boiling point is above 60 ° C and against acid vapors such as:

• - sulfurous and sulfuric anhydride
• - nitrogen oxides
• - halogenated acids: hydrochloric, hydrobromic, hydroiodic
• - hydrogenated acices: hydrogen sulfide, mercaptans, and in general wherever non-fibrogenic dust is a nuisance for the user with emission of organic or acid vapors and in particular against polyurethane and isocyanate vapors (when their concentration is less than 0.2 ppm.).

Claims (2)

1. Disposable respiratory mask comprising a shell (C) of heat-shrinkable materials comprising an outer sheet (C1) which is permeable to the fluid to be treated and possesses a plurality of cells (A1-A6) projecting, on its anterior face, from the said outer sheet and occupying virtually all the surface thereof, each of the said cells defining an enclosure containing a filtering granular material, particularly activated charcoal, highly compressed within the said enclosures, the said cells being closed by an inner sheet (C2) which is permeable to the fluid to be treated and is applied to the outer sheet during a thermal welding operation, characterized in that it possesses a semi-rigid intermediate plate (B) which is impermeable to the fluid to be treated and is arranged between the said outer (C1) and inner (C2) sheets and provided with holes (T1-T6) of a shape and arrangement corresponding to those of the cells (A1-A6), the said holes (T1-T6) having dimensions less than those of the base of the corresponding cells, in a manner such as to deflect the air entering towards the granular product.

2. Method of manufacturing a respiratory mask according to Claim 1, characterized in that:

- cells (A1-A6) are produced by deformation on a sheet (C1) of heat-shrinkable material;

- holes (T1-T6) of a shape and arrangement corresponding to those of the cells (A1, A2) are cut in a semi-rigid intermediate plate (P), each of the said holes possessing dimensions less than those of the base of the corresponding cell;

- the cells (A1-A2, etc.) are entirely filled with a filtering granular material;

- the intermediate plate (P) is placed on the sheet (C1), its holes (T1-T6) being brought into alignment with the cells (A1-A6);

- an inner sheet (C2) is placed on the sheet (C1) in a manner such as to cover the cells;

- hot and flat welding of the said sheets is carried out in order to close the cells and, at the same time, to deform these sheets by shrinkage;

- two V's are cut at the upper and lower ends to facilitate folding;

- these cut-outs are welded to give the configuration ofthe mask.

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