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Patent Searching and Data


Title:
【発明の名称】容器内の気体の圧力を測定する方法およびそれを実行するための装置
Document Type and Number:
Japanese Patent JP2001517784
Kind Code:
A
Abstract:
Two resistance elements (3, 6) are used for eliminating the influence of wall temperature on the gas pressure in a vessel, determined by a Pirani manometer. The first resistance element (3) is present in a first branch of a Wheatstone bridge (1), and the voltage is tapped by means of a voltage divider (7). The second resistance element (6) is present with a series resistance (5) in the second branch and is adjusted to a lower temperature. The changes in the voltages tapped at the branches are essentially identical for identical temperature changes at the resistance elements (3, 6), so that the Wheatstone bridge (1) remains balanced. The adjustment is improved by a constant current source (11). Another embodiment uses only one resistance element, whose temperature is reduced periodically during the balancing of the Wheatstone bridge and, after thermal equilibrium has been established, is determined by determining its resistance by means of a low constant current and is used for the computational compensation of the effect of the wall temperature. In a further embodiment, transient effects are produced by periodically switching a resistance back and forth and the frequencies are measured, from which the gas pressure is then determined.

Inventors:
Rolf, Norbert
Stocker, rudolf
Application Number:
JP2000513120A
Publication Date:
October 09, 2001
Filing Date:
September 01, 1998
Export Citation:
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Assignee:
Unakis Balzers Akchengezel Shaft
International Classes:
G01L21/12; (IPC1-7): G01L21/12
Attorney, Agent or Firm:
Fukami Hisaro (5 others)