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(11) | EP 0 024 133 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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| (54) |
Air supply units Luftversorgungseinheiten Unités pour l'alimentation en air |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[0001] The invention relates to an air supply unit suitable for blowing air to a face mask for the respiratory protection of a person working in a noxious or unpleasant industrial atmosphere. Examples of environments in which such a unit is useful include work-places where there is dust or fumes.
[0002] Previous proposals include Patent Specifications DE 2823446 A1 (corresponding to UK 1588993) which shows a housing 30 containing a blower 32, filter discs 42 held in position by caps 38, and a battery pack 34. The blower 32 draws air in through the filters 42, and over the battery 34, and blows it through a conduit 28 to a face piece. There is also US 3496703 which shows electrical components secured to an upper shelf 23.
[0003] According to the invention, the unit comprises a casing, a central plate to which motor, battery and other electrical components are secured forming an integral part of the casing, a removable back plate and the cap having a central part removable leaving a rim for securing a supplementary filter unit.
[0004] A centrifugal fan has been found necessary to produce sufficient pressure at reasonable power consumption and with a reasonable filter area.
[0005] The filter unit upstream of the fan reduces any tendency for the unit to become clogged with dust or other foreign matter. The filter unit may comprise a pre-filter or glass fibre mat, followed by a folded-paper unit to remove dust or an activated carbon unit to absorb organic vapours.
[0006] The casing containing all the operative components makes the unit easy to handle and maintain. Preferably, the casing is a plastics moulding and includes a back plate removable to provide access to the motor, battery, and other electrical components such as switches. The casing also includes a centre plate to which the motor, fan, battery and other electrical components are releasably secured, for example by screws, so that each can readily be removed for replacement or maintenance. The casing may be provided with loops for a belt for the user, but may be free-standing for example for use on a work bench or in a tractor cab.
[0007] The filter unit is preferably across the front of the casing, and the filter itself held in position by an apertured cap, and secured to the casing by screw-threads. A central part of the apertured cap is removable, leaving a rim for securing a supplementary filter unit projecting out of the casing through the cap. The fan draws in-coming air through the apertured cap and filter, and impels filtered air to the downstream duct.
[0008] The battery is preferably below the motor and duct so as fully to utilize the space available. The battery may be rechargeable through a connection on the side of the casing, and preferably comprises sealed lead/acid or nickel cadmium cells. The motor is preferably of low inductance which is intrinsically safe in an explosive atmosphere. The unit can be made so light that its weight on the belt is not noticable.
Drawings
[0009]
Figure 1 is a front elevation of a unit according to the invention with components shown in broken lines;
Figure 2 is a section along A-A of Figure 1;
Figure 3 is a side view corresponding to Figure 1; and
Figure 4 is an outside plaii corresponding to Figure 1.
[0010] In the drawings, a main casing 34 (Figure 2) contains a centrifugal fan 10, a filter unit 12 upstream, and a duct 14 downstream for guiding blown air to a tube (not shown) incorporating a non-return valve for transmission to a face mask (not shown). The unit is self-contained with an electric motor 18 for driving the fan 10, a rechargeable battery 20 mounted on a central plate 36 (Figure 2), and belt loops 22 on the outside.
[0011] An apertured cap 24, with a pre-filter mat 13 trapped therein, secures the filter unit 12 in position and is retained by screw threads 26 covering four segments of the circumference for quick mounting and release. By breaking out the central part of the cap 24, including ribs 40 (Figure 1), a circumferential rim 42 can be left for securing a second filter unit 44 in front of the unit 12 as in Figure 3.
[0012] A back plate 32 is screwed onto the main casing 34, and can be removed to expose the motor 18 backing onto the fan 10, the battery 20, and a centre plate 36, an on-off switch or control knob 46, and a battery re-charge socket 48. A safety fuse 50 is provided in the electrical circuit adjacent the motor 18.
1. An air supply unit comprising a casing (34), a centrifugal fan (10) a filter unit
(12) upstream of the fan (10) held in position by an apertured cap (24) secured to
the casing (34) by screw threads (26), a duct (14) downstream of the fan (10) for
guiding blown air to a tube for transmission to a face mask, an electric motor (18)
for driving the fan (10), a battery (20) for powering the motor (18), the motor (18),
fan (10), battery (20) and other electrical components being secured to a centre plate
(36) and the casing including a back plate (32) removable to provide access to the
motor (18) battery (20), and other electrical components, characterized by the centre
plate (36) forming an integral part of the casing (34) and the cap (24) having a central
part (40) removable leaving a rim for securing a supplementary filter unit (44).
1. Une unité d'alimentation en air comprenant un boîtier (34), un ventilateur centrifuge
(10), une unité de filtre (12) en amont du ventilateur (10) maintenue en position
par un couvercle ajouré (24) fixé sur le boîtier (34) par des pas de vis (26), un
conduit (14) en aval du ventilateur (10) pour guider l'air soufflé vers un tube pour
la transmission à un masque facial un moteur électrique (18) pour entraîner le ventilateur
(10), une batterie (20 pour alimenter le moteur (18), les moteur (18), ventilateur
(10), batterie (20) et autres composants électriques étant fixés à une plaque centrale
(36) et le boîtier comprenant une plaque arrière (32) amovible pour permettre l'accès
au moteur (18), batterie (20), et autres composants électriques, caractérisé en ce
que la plaque centrale (36) forme partie d'un seul tenant du boîtier (34) et que le
couvercle (24) possède une partie centrale (40) amovible laissant une bordure pour
fixer une unité supplémentaire de filtre (44).
1. Luftversorgungsgerät bestehend aus einem Gehäuse (34), einem Zentrifugalgebläse
(10), einer dem Gebläse (10) vorgeschalteten Filtereinheit (12), die von einer mit
Öffnung versehenen Kappe (24) in Lage gehalten wird, wobei, die Kappe mittels Schraubgewinde
(26) am Gehäuse befestigt wird, einen dem Gebläse (10) nachgeschalteten Luftkanal
(14), durch den Blasluft einem Schlauch zur Weiterleitung an eine Gesichtsmaske zugeführt
wird; einem Electromotor (18) zum Antrieb des Gebläses (10), einer Batterie (20) als
Stromquelle für den Motor (18), wobei de Motor (18), das Gebläse (10), die Batterie
(20) und andere elektrische Bauteile an einer zentralen Platte (36) befestigt sind,
und wobei da Gehäuse eine abnehmbare Rückplatte (32) aufweist, um Zungang zum Motor
(18) zur Batterie (20) und anderen elektrischen Bauteilen zu ermöglichen, dadurch
gekennzeichnet dass die zentrale Platte (36) ein Teil des Gehäuses (34) bildet und
dass die Kappe (24) ein mittig angeordnetes Teil (40) aufweist, das sich entfernen
und dadurch einen Rand zur Befestigung einer zusätzlichen Filtereinheit (44) stehen
lässt.