초록 ▼

An environmental control hood assembly includes a headpiece and a noise filter subassembly which is disposed within the headpiece adjacent its top wall. The filter subassembly includes a silencer member with an air-permeable wall portion and is connected to the conduit which in turn is connected to

An environmental control hood assembly includes a headpiece and a noise filter subassembly which is disposed within the headpiece adjacent its top wall. The filter subassembly includes a silencer member with an air-permeable wall portion and is connected to the conduit which in turn is connected to the source of air under pressure. The silencer member in turn is disposed within a foam member which is fabricated of an air-permeable synthetic resin open cell foam so that air introduced into the silencer member must travel a path through the silencer member and through the foam with resultant reduction in the sound level of that air. A barrier may be provided under the silencer to preclude direct flow of air from the silencer downwardly through the foam, and the filter subassembly may include a bottom sheet of an air-pervious material.

대표청구항 ▼

In an environmental control hood assembly, the combination comprising: A. a headpiece assembly including 1. a headpiece dimensioned to receive the user\s head therewithin and having a top wall and a sidewall, said headpiece being transparent at least about a portion of the sidewall thereof, said hea

In an environmental control hood assembly, the combination comprising: A. a headpiece assembly including 1. a headpiece dimensioned to receive the user\s head therewithin and having a top wall and a sidewall, said headpiece being transparent at least about a portion of the sidewall thereof, said headpiece including a support member having a surface positioned below and in spaced relationship to said top wall to define a chamber therebetween, said support member being secured to a wall of said headpiece and being pervious to air about at least a portion of the surface thereof to permit air to flow from said chamber into the remainder of the space defined by said headpiece; 2. a noise filter subassembly disposed in said chamber and including a. a silencer member having an inlet at one end, a closed wall at the opposite end and an air-permeable wall portion therebetween; b. a foam member encasing said silencer member and fabricated of an air-permeable synthetic resin open cell foam; B. air supply conduit means connected at one end to said inlet of said silencer member and extending outwardly of said headpiece assembly for connection to a source of air under superatmospheric pressure, whereby air supplied to said headpiece assembly through said air supply conduit means must pass first through said air-permeable wall portion of said silencer member and thence said air-permeable foam member with resultant reduction in the sound level of the supplied air.