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Apparatus For And Method of Determining the Colloid Content In Ultra-Pure Water

IP.com Disclosure Number: IPCOM000099716D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Hoffmeister, W: AUTHOR

Abstract

To cope with the increasingly rigid requirements for DI water purity, a new filtration method has been developed for determining the colloid content.

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This is the abbreviated version, containing approximately 76% of the total text.

Apparatus For And Method of Determining the Colloid Content In Ultra-Pure Water

       To cope with the increasingly rigid requirements for DI
water purity, a new filtration method has been developed for
determining the colloid content.

      The measuring set-up and process used are described below with
reference to the figure.

      Tank 1 serves to accommodate 130 ml of DI water to be analyzed
which is filled into the tank through opening 2 sealed by screw cap
3.  Tank 1 is made of a thick-walled plastic material to avoid
viscosity variations caused by temperature changes, as the filtration
speed is viscosity, and thus temperature, dependent.

      Base plate 4, fixed to tank 1 by four threaded screws,
accommodates membrane filter 5, whose active filter surface is
determined by five bores 6 of a diameter of 0.2 mm.  For filtration,
a 0.22 m filter is used, followed by a 3.0 m filter, preventing the
former filter from rupturing.

      For filtration, nitrogen is applied through inlet opening 7 at
a pressure of 0.1 bar.  The filtered DI water is discharged through
opening 8 into collector tank 9.  The filtered volume is measured by
weighing tank 9 by an electronic digital balance on which tank 9 is
positioned for the duration of testing.  For time measurement, the
balance is connected to a PC.

      As membrane filters initially expand, measurement starts only
after 20 ml DI water have been filtered.  The filtration volume is 10
ml, and...