Method for measuring the gas pressure in a container, and devices for its application
US6474172B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | May 10, 2000 |
| Grant date | Nov 5, 2002 |
| Priority date | — |
| Expiry date | May 10, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L21/12
- WIPO fieldMeasurement
- WIPO sectorInstruments
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 meas…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.