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Room ventilating device

  • US 4,257,319 A
  • Filed: 05/04/1978
  • Issued: 03/24/1981
  • Est. Priority Date: 05/09/1977
  • Status: Expired due to Term
First Claim
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1. Ventilating device for rooms having air passage apertures and closure means slidable between a closed position in which it is effective to block the apertures and an open position in which the apertures are unblocked, said ventilating device comprising:

  • (a) an electric drive for reciprocating the closure means between said open and closed positions,(b) an electric supply main,(c) a noxious gas sensor for producing an electrical signal when the noxious gas concentration in the room to be ventilated reaches a predetermined level,(d) a first switch connected to the electrical drive,(e) a second switch connected to the electrical drive,(f) a cam operatively connected to the electric drive for simultaneous movement with said electric drive, said cam being effective to close the first switch and open the second switch when the closure means is at the closed position and during movement of the closure means to the open position, and being effective to open the first switch and close the second switch when the closure means is at the open position and during movement of the closure means to the closed position,(g) a primary relay connected to the noxious gas sensor for receiving said electrical signal, said relay having an inactive state in the absence of said electrical signal and an active state when receiving said electrical signal, said relay having a contact which is effective to connect the first switch to the electric supply main only when the relay is in said inactive state and effective to connect the second switch to the electrical supply main only when the relay is in said active state, whereby said apertures will be unblocked when the noxious gas concentration in the room reaches said predetermined level and blocked when the noxious gas concentration in the room is below said predetermined level,(h) a sound sensor for producing a second electrical signal when the environmental sound reaches a predetermined volume, and(i) electrical circuitry operatively connected to said primary relay and first and second switches and responsive to said second electrical signal for shifting said closure means from said open position to said closed position for a predetermined time period.

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