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Fume hood controller

  • US 4,706,553 A
  • Filed: 05/08/1985
  • Issued: 11/17/1987
  • Est. Priority Date: 03/05/1984
  • Status: Expired due to Term
First Claim
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1. A fumed hood controller for controlling the air flow through a fume hood to maintain a relatively constant face velocity through a fume hood opening as the fume hood sash is moved, comprising:

  • transducer means responsive to the position of the fume hood sash for producing a sash opening signal the value of which is a substantially continuous and monotonic function of the sash opening;

    air flow control means, responsive to an air flow signal, for varying the air flow through the fume hood in accordance with the air flow signal;

    flow control means, responsive to the sash opening signal, for producing the air flow signal, including;

    means for setting a first air flow at a first sash position;

    means for setting a second air flow at a second sash position; and

    means for providing, to the air flow means, an air flow control signal having a value so as to maintain the air flow through the hood substantially proportional to the sash opening area as the sash is moved between the first and second sash positions, said means for providing including means for maintaining a linear relationship between the air flow signal and the air flow through the hood.

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