WO1991005584A1

WO1991005584A1 - Respiratory protection device

Info

Publication number: WO1991005584A1
Application number: PCT/GB1990/001581
Authority: WO
Inventors: Harry Cole
Original assignee: Harry Cole
Priority date: 1989-10-12
Filing date: 1990-10-12
Publication date: 1991-05-02
Also published as: JP2928381B2; CA2067195A1; JPH05500915A; EP0495864A1; GB2236681B; CA2067195C; AU6602590A; GB2236681A; GB8922951D0

Abstract

A face mask (1), covering at least the nose and mouth, has an air-permeable region (holes 9) for extending over the nasal and oral orifices and has means (7, 8) for attaching the mask to the head. A disposable flexible air-permeable filter (2) extends over the nasal and oral orifices, in contact with the face, and is temporarily connected to the face mask (1) by non-return exhalation valves (12).

Description

Respiratory Protection Device

This invention relates to a respiratory protection device comprising a face mask with a filter. The device is intended particularly, but not solely, for the use of cyclists in built-up areas and on roads with high traffic density.

The invention provides a respiratory protection device comprising a resiliently stretchable face mask of spongy material for covering at least the nose and mouth, the face mask having an air-permeable region for extending over at least the nasal and oral orifices, the face mask including at least one non-return exhalation valve, a disposable flexible air-permeable filter for extending over at least the nasal and oral orifices, the filter being in direct contact with the face when the device is worn, temporary connecting means connecting the exhalation valve to a corresponding aperture in the filter, and means for attaching the face mask to the head so that the filter is sandwiched between the face mask and the face.

The face mask preferably has a porous fabric (e. g. cotton) lining, so as not to interfere too greatly with perspiration. The face mask conveniently has side pieces which carry the attaching means and which can be connected together at the back of the head. Preferably the rear ends of the side pieces carry respective loops and hooks for connection together; the rear ends are preferably enlarged so that the rear ends can be overlapped to different degrees to accommodate different head sizes. The face mask is resiliently stretchable, which facilitates a good fit. The face mask may be made, for example, from " Plastazote" or "Evazote" (Trade Marks of BXL Plastics Ltd. for closed-cell cross-linked polyethylene and co-polymer foams ) or expanded neoprene.

The filter preferably comprises active carbon, preferably in the form of activated charcoal cloth. The surface of the cloth which is to contact the face preferably has a lining, such as a particulate lining for the sake of comfort, enhanced strength, improved handling, and increased ability to trap air-borne particulate matter.

Activated charcoal cloth is woven from charcoal yarn and is non-toxic. It has the ability to physically and chemically trap odours, vapours, bacteria, viruses, acid gases, and dust of a size greater than 0.5 μm. With respect to vehicle exhaust pollutants, it exhibits excellent adsorption of aromatic hydrocarbons and particulate matter, poor adsorption of carbon monoxide, moderate adsorption of sulphur dioxide, and poor adsorption of nitrogen dioxide.

Impregnation of the filter with platinum may increase its ability to adsorb carbon monoxide. Impregnation of the filter with copper^' gives it excellent ability to chemisorb nitrogen dioxide and sulphur dioxide. A non-woven fabric lining may be impregnated with potassium permanganate to enhance chemisorbtion of acid gases and also to offer an indication, by way of a colour change, when the filter is due for replacement.

. The face mask preferably incorporates one or more nose clips which can be plastically deformed to fit the bridge of the nose in order to minimize leakage round the edge of the filter.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an exploded perspective view of a respiratory protection device;

Figure 2 is a side view of an exhalation valve;

Figure 3 is an axial section through the valve, taken on line B-B in Figure 2;

Figure 4 is a section taken on line C-C in Figure 2; and

Figure 5 is an axial section through an annular connection member.

The respiratory protection device illustrated comprises a face mask 1 and a filter 2 which fits in the face mask and is in direct contact with the face when the device is worn.

The face mask 1 is of expanded neoprene sandwiched between knitted fabric coverings. It has a face-covering portion 3, which is to extend vertically from the top of the nose to the chin and horizontally from cheek to cheek, and integral side pieces 4 whose rear ends 6 are enlarged and bear respectively "Velcro" (Registered Trade Mark) hook material 7 and loop material 8. The mask has through-holes 9 defining an air-permeable region corresponding to the region of the nasal and oral orifices.

Near each end of the mouth the mask has an aperture 11 in which a non-return exhalation valve 12 is fixed. The valve has a cover 13 with peripheral openings 14, a freely-movable valve disc 16, an annular valve seat 17 which projects into the mask through the aperture 11, and an annular retaining member 18 which clamps the periphery of the aperture 11 to the valve seat 17 and cover 13.

A plastically deformable nose clip 20 comprising a pressing made from annealed aluminium is incorporated in the face mask 1 in the region of the bridge of the nose. The filter 2 has a shape corresponding to that of the face-covering portion 3 of the mask. It comprises an outer layer of particulate non-woven material, a middle layer of activated charcoal cloth, and an inner layer or lining of particulate non-woven material. The filter 2 is made in two parts stitched together along a seam 21.

The filter 2 has two apertures corresponding to the mask apertures 11 and each containing an annular connection member 24 having a flange 26 on the side of the filter adjacent the face, and a tube 28 which projects out through the filter. The tube 28 is an interference fit in the bore of the retaining member 18 of the corresponding exhalation valve 12.

Thus, owing to the separable interconnection of the face mask 1 and the filter 2 by the interengagement of the connection members 24 and the valves 12 and owing to the sandwiching of the filter 2 between the mask 1 and the wearer' s face, the filter 2 is located in a stable and most effective position and yet is easily removable for replacement.

Claims

1. A respiratory protection device comprising a resiliently stretchable face mask (1) of spongy material for covering at least the nose and mouth, the face mask (1) having an air-permeable region for extending over at least the nasal and oral orifices, the face mask (1) including at least one non-return exhalation valve (12), a disposable flexible air-permeable filter (2) for extending over at least the nasal and oral orifices, the filter (2) being in direct contact with the face when the device is worn, temporary connecting means (24) connecting the exhalation valve (12) to a corresponding aperture in the filter, and means for attaching the face mask (1) to the head so that the filter (2) is sandwiched between the face mask (1) and the face.

2. A device as claimed in claim 1, in which the exhalation valve (12) is adjacent one end of the mouth when the device is worn.

3. A device as claimed in claim 2, in which there are two said exhalation valves (12) adjacent respective ends of the mouth.

4. A device as claimed in claim 1, in which the temporary connecting means comprises an annular member (24) which extends through the aperture and is releasably engaged with the valve (12).

5. A device as claimed in claim 4, in which the annular member (24) has a flange (26) on the side of the filter (2) adjacent the face.

6. A device as claimed in claim 1, in which the air permeable region of the face mask (1) has a plurality of through-holes (9).

7. A device as claimed in claim 1, in which the face mask (1) has a porous fabric lining.

8. A device as claimed in claim 1, in which the face mask (1) has side pieces (4) which carry the attaching means and can be connected together at the back of the head.

9. A device as claimed in claim 8, in which the rear ends (6) of the side pieces (4) are enlarged and carry respective loops (8) and hooks (9) for connection together.

10. A device as claimed in claim 1, in which the filter (2) comprises active carbon.

11. A device is claimed in claim 10, in which the filter (2) comprises activated charcoal cloth.

12. A device as claimed in claim 11, in which the surface of the cloth which is to contact the face has a lining.

13. A device as claimed in claim 1, in which the filter is impregnated with platinum and/or copper and/or potassium permanganate.