Photo-ionization detector for volatile gas measurement and a method for self-cleaning the same
US6225633A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 22, 1998 |
| Grant date | May 1, 2001 |
| Priority date | — |
| Expiry date | Oct 22, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N33/0047
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A photo-ionization detector (PID) includes an ultraviolet (UV) lamp that transmits UV light into an ionization chamber to ionize volatile gases. An ion detector in the ionization chamber includes interdigital electrodes that collect resulting ions using an electrical field perpendicular to the UV light propagation. A pump in the PID circulates gases through the ionization chamber in a direction perpendicular to the electrical field and to the UV light propagation. The PID additionally provides a UV monitor having interdigital electrodes that release electrons when struck by the UV light. The size of a monitor current in the UV monitor indicates the intensity of the UV light. The UV monitor is in a UV monitor chamber that protects the UV monitor from exposure to the ionized gases and improves the accuracy of UV intensity measurements. The interdigital electrodes of the ion detector and the UV monitor can be manufactured by forming an electrode layer on a substrate and selectively patterning the electrode layer to produce interdigital electrodes. If the substrate is not transparent to UV light, the substrate can be removed or patterned to match the interdigital electrodes. To remove …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.