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Condensation Indicator for Humidity Chambers

IP.com Disclosure Number: IPCOM000095997D
Original Publication Date: 1964-Nov-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Pawlowski, EJ: AUTHOR

Abstract

The indicator sounds an alarm when condensation forms within a humidity chamber due to a malfunction in its operation. Sensing unit 1 which includes insulating substrate 2 having two closely spaced conductive concentric spirals 3 and 4 on it is placed in the humidity chamber.

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Condensation Indicator for Humidity Chambers

The indicator sounds an alarm when condensation forms within a humidity chamber due to a malfunction in its operation. Sensing unit 1 which includes insulating substrate 2 having two closely spaced conductive concentric spirals 3 and 4 on it is placed in the humidity chamber.

Unit 1 has transistor 5 connected across its spirals 3 and 4. The base of transistor 5 connects to spiral 3 and the collector of transistor 5 connects to spiral
4. One of the spirals is also connected to power source B+ through relay 6. When moisture falls onto unit 1, a feeble current flows from the collector to base of transistor 5. This current energizes relay 6 which, in turn, sounds the alarm. Multiple sensing units can be placed in parallel electrical connection in the humidity chamber.

Spirals 3 and 4 are composed of a noble metal with a small amount of binder material, such as a glass frit, to improve the adhesion of the spirals to substrate
2. The preferred noble metal-binder composition is platinum-bismuth trioxide. A typical pattern having concentric spirals of five mil width and five mil spacing can be screened onto substrate 2 by conventional silk screening techniques. The screened-on pattern of noble metal and binder composition is fired at a temperature above the softening point of the binder composition to fuse the pattern into a solid mass. Corrosion resistant pins are inserted into the substrate and are connected to spirals 3 and...