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Continuous Transducer Monitoring of Film Or Tape Loop Position Within a Vacuum Column

IP.com Disclosure Number: IPCOM000037802D
Original Publication Date: 1989-Jul-01
Included in the Prior Art Database: 2005-Jan-30
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Yarrington, JC: AUTHOR

Abstract

A vertical slot cut through the back wall of a standard vacuum column, into a closed chamber, with its midpoint approximating the nominal position of the bottom of the tape loop, permits air flow from the atmosphere, into the chamber and then out to the vacuum side of the tape loop. This air flow, and consequently the pressure within the chamber, varies as the division of the slot into an input and an output ports is changed by vertical movement of the tape loop. By monitoring the chamber pressure, the position of the tape loop is continuously approximated.

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Continuous Transducer Monitoring of Film Or Tape Loop Position Within a Vacuum Column

A vertical slot cut through the back wall of a standard vacuum column, into a closed chamber, with its midpoint approximating the nominal position of the bottom of the tape loop, permits air flow from the atmosphere, into the chamber and then out to the vacuum side of the tape loop. This air flow, and consequently the pressure within the chamber, varies as the division of the slot into an input and an output ports is changed by vertical movement of the tape loop. By monitoring the chamber pressure, the position of the tape loop is continuously approximated.

Figures 1 and 2 show schematics of the present embodiment. It is seen that Slot 1 is cut through the back wall of the vacuum column into Chamber 2. It is further seen that Slot 1 is divided by Tape Loop 3 into Segment 4 and Segment 5, and that there is air Flow 6 from the atmosphere into Chamber 2 through slot Segment 4 and then out of Chamber 2 through slot Segment 5 to Vacuum 7. It is apparent that if Tape Loop 3 moves up to position 8 that slot Segment 4 is shortened and slot Segment 5 is lengthened, and that the converse is effected if the Loop moves to a lower position. It is also seen that transducer T-1 senses the pressure differential across slot Segment 4, and that transducer T-2 senses the pressure differential across slot Segment 5. It is further apparent that, if Segment 4 is the larger, air is flowing into Chambe...