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Title: Instrument for measurement of vacuum in sealed thin wall packets

An instrument for the measurement of vacuum within sealed packets 12, the packets 12 having a wall 14 that it can be deformed by the application of an external dynamic vacuum to an area thereof. The instrument has a detector head 18 for placement against the deformable wall 14 of the packet to apply the vacuum in a controlled manner to accomplish a limited deformation or lift of the wall 14, with this deformation or lift monitored by the application of light as via a bifurcated light pipe 20. Retro-reflected light through the light pipe is monitored with a photo detector 26. A change (e.g., a decrease) of retro-reflected light signals the wall movement such that the value of the dynamic vacuum applied through the head be to achieve this initiation of movement is equal to the vacuum within the packet 12. In a preferred embodiment a vacuum plate 44 is placed beneath the packet 12 to ensure that no deformation occurs on the reverse surface 16 of the packet. A vacuum can be applied to a recess in this vacuum plate, the value of which can be used to calibrate the vacuum transducer in the detector head.
 [1];  [2];  [3]
  1. (Oak Ridge, TN)
  2. (Knoxville, TN)
  3. (Lexington, KY)
Issue Date:
OSTI Identifier:
Martin Marietta Energy Systems, Inc. (Oak Ridge, TN) ORNL
Patent Number(s):
US 5406831
Contract Number:
Research Org:
Country of Publication:
United States
instrument; measurement; vacuum; sealed; wall; packets; 12; 14; deformed; application; external; dynamic; detector; head; 18; placement; deformable; packet; apply; controlled; manner; accomplish; limited; deformation; lift; monitored; light; via; bifurcated; pipe; 20; retro-reflected; photo; 26; change; decrease; signals; movement; value; applied; achieve; initiation; equal; preferred; embodiment; plate; 44; placed; beneath; ensure; occurs; reverse; surface; 16; recess; calibrate; transducer; dynamic vacuum; preferred embodiment; reflected light; light pipe; controlled manner; light signal; light signals; detector head; sealed packets; deformable wall; deformation occurs; wall packets; /73/356/