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Isolation valve for single crystal pulling apparatus

  • US 5,356,113 A
  • Filed: 09/23/1993
  • Issued: 10/18/1994
  • Est. Priority Date: 09/30/1992
  • Status: Expired due to Fees
First Claim
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1. An isolation valve for a single crystal pulling apparatus, the single crystal pulling apparatus having a main chamber in which a crucible holds a melt of a raw material, the single crystal pulling apparatus having a pull chamber which receives a single crystal pulled from the melt, the isolation valve for the single crystal pulling apparatus comprising:

  • a valve casing having two opposing valve seats, a first valve seat having a first opening communicable with a main chamber, a second valve seat having a second opening communicable with a pull chamber;

    a valve rod having a longitudinal axis located within the valve casing, the valve rod being longitudinally movable along the axis and rotatable about the axis;

    a valve body rotatably mounted within the valve casing about the longitudinal axis, the valve body including a first plate movable in and out of sealing contact with the first valve seat to open and shut the first opening, a second plate movable in and out of sealing contact with the second valve seat to open and shut the second opening, and a bellows connecting the first plate to the second plate, the first plate being fastened to the valve rod;

    a passage communicable with a fluid supply and with an interior of the valve body defined by the first plate, the second plate and the bellows, the passage enabling a working fluid from the fluid supply to pass to the interior of the valve body;

    a spring biasing member acting on the valve rod, the biasing member biasing the valve rod axially so that the first plate is out of contact with the first valve seat during rotation of the valve body; and

    means, provided intermediate the passage, for controlling the pressure of the interior of the valve body, the controlling means having a first set pressure of the working fluid at which the first plate is in sealing contact with the first valve seat and the second plate is in sealing contact with the second valve seat, the controlling means having a second set pressure of the working fluid at which the first plate is out of sealing contact with the first valve seat and the second plate is out of contact with the second valve seat.

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