Abstract: Breathing responsive powered air purifying respirator apparatus comprising an air-tight housing having connections for filters (5) and for supply of purified air to a face mask (3), a motor-driven blower arranged inside said air-tight housing for drawing air through said filter units and for the supply of purified air to the face mask. The blower is a lobe blower (6) delivering a constant flow of air. A regulator (10) is arranged in said housing in parallel with the lobe blower (6), and a by-pass conduit (11) connects the outlet side (12) of the lobe blower to the inlet side (13) of the lobe blower, wherein said regulator is arranged to open said by-pass conduit, when a pressure in the face mask exceeds a predetermined positive pressure.

Abstract: This invention relates to a pressure compensating valve and more particularly, but not exclusively, to a balanced pressure compensating valve, or regulator. The valve includes a chamber (6) for containing fluid, defined by a flexible barrier (2) trapped between first (3) and second (4) surfaces. A fluid inlet provides fluid to the interior of the chamber. A fluid outlet selectively allows fluid to pass out of the chamber. Movement of the first (3) and second (4) surfaces relative to each other causes change in contact between the flexible barrier and the first and second surfaces to selectively open the fluid outlet, in a first position, and occlude it between the flexible barrier and one of the surfaces, in a second position.

Abstract: The present invention relates to a particular type of fan-forced positive pressure breathing apparatus, commonly known as Powered Air-Purifying Respirators (PAPRs). In particular the invention concerns monitoring the operation of such equipment. In a first aspect, the invention provides a powered air-purifying respirator which includes data collection means to enable the volume of air drawn through the filter to be determined. In another aspect, the invention comprises a management system for monitoring and analyzing operational data from at least one powered air-purifying respirator. The management system includes data collection means associated with each respirator to enable the volume of air drawn through that respirator's filter to be determined, and electronic data processing apparatus into which the data collected by the data collection means is uploaded for analysis.

Abstract: A forced air breathing apparatus which includes a face piece (20a) for covering at least the nose or mouth of a wearer, a pump unit (10) arranged to supply air to a space within the face piece (20a), a filter (13) to filter air entering the face piece (20a) and valve means to control the flow of air from the pump unit (20) to the face piece (20a) during inhalation and from the face piece (20a) during exhalation. The pump unit (20) includes a fan (12) driven by an electric motor (11). The valve means includes an air inlet valve (19) and an air outlet valve (22), the air outlet valve (22) being maintained in a closed position during inhalation through the air inlet valve (19) by air pressure from the pump unit (20) and being opened by exhaled air. The exhaled air also acts to close the air inlet valve (19) and prevents the entry of exhaled air to the pump unit (20). The fan (12) is a centrifugal fan driven at a substantially constant speed.