Critical flow based mass flow verifier
US7474968B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 2006 |
| Grant date | Jan 6, 2009 |
| Priority date | — |
| Expiry date | Dec 14, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01F25/15
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A flow verifier for verifying measurement by a fluid delivery device under test (DUT) includes a chamber configured to receive a flow of the fluid from the DUT, at least one temperature sensor to provide gas temperature in the chamber, at least one pressure transducer to provide gas pressure in the chamber, and a critical flow nozzle located upstream of the chamber along a flow path of the fluid from the DUT to the chamber. The critical flow nozzle and the flow verification process are configured to maintain the flow rate of the fluid through the nozzle at the critical flow condition such that the flow rate through the nozzle is substantially constant and substantially insensitive to any variation in pressure within the chamber downstream of the nozzle. Therefore, the varying chamber pressure during the flow verification period has substantially no impact on the downstream pressure of the DUT, and the external volume between the flow verifier and the DUT is substantially irrelevant to the flow verification calculation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.