Breathing apparatus

  • US 4,590,951 A
  • Filed: 06/06/1984
  • Issued: 05/27/1986
  • Est. Priority Date: 06/07/1983
  • Status: Expired due to Fees
First Claim
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1. A power assisted respirator comprising a facepiece defining a space for covering the mouth and nose of the wearer and having an inlet and an outlet for air, one-way exhale valve means in said outlet which is operable to permit air to flow out of said space within said facepiece when a predetermined differential pressure is established thereacross, non-positive displacement pump means having inlet means for air and an outlet, said pump means permitting, in its inoperative state, flow of gas between said inlet means and said outlet, battery means connected to said pump means for energizing said pump means, said outlet being connected to the inlet of said facepiece for supplying air thereto, one-way inlet valve means between said pump outlet and said space, said one-way inlet valve means permitting air to flow from said pump outlet to said space through said inlet of said facepiece but not in the reverse direction when the pressue in said space exceeds the pressure at the outlet of said pump means, the operating parameters of said pump means and said exhale valve means being selected so that, during exhalation by the wearer, the inlet valve means will close and the pump means will be placed in a condition in which it will substantially cease to operate effectively, filter means connected to said inlet means of said pump means for filtering air supplied thereto, pressure sensor means connected between said pump means and said filter means for sensing the pressure of air passing between said pump means and said filter means, and control means responsive to said pressure sensor means for causing disconnection of said pump means from said battery means when the pressure sensed by said pressure sensor means rises above a preset level.

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