Flow indicator device for respirators
Assignee3M Innovative Properties Company
InventorIan T. Petherbridge
Life of this patent
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Abstract
A respirator that comprises a head piece (1) that is shaped to form a breathing zone (13) around at least the nose and mouth of the wearer, and an air flow passage (15, 34) for supplying a forced flow of air to the breathing zone. The air flow passage has a constricted portion (46) that includes a flow detecting orifice (52). The forced flow of air generates suction at the flow-detecting orifice. A pressure-responsive indicator device (30) is in fluid communication with the flow-detecting orifice through a tube (54) and is operable to alert the wearer if the suction generated by the air flow through the passage falls below a predetermined value.
Claims11
A respirator that is capable of directing a forced flow of filtered air to a wearer, the respirator comprising:
- a head piece that is adapted to form a breathing zone around at least the nose and mouth of the wearer,
- an air flow passage through which a forced flow of filtered air passes before entering the breathing zone, the passage having a constricted portion containing a flow detecting orifice such that the forced flow of air generates suction at the flow-detecting orifice, the degree of suction being related to the air flow rate in the passage;
- and
- a pressure-responsive indicator device that is in fluid communication with the flow-detecting orifice and operable to alert the wearer if the suction generated by the air flow through the passage falls below a predetermined value.
Dependencies are inferred from the claim text.