Porometer and method for stomatal measurements
US4312218A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 4, 1979 |
| Grant date | Jan 26, 1982 |
| Priority date | — |
| Expiry date | Sep 4, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N15/08
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
To measure stomatal resistance of a leaf, signals are obtained from: (1) a small thermocouple positioned adjacent to the leaf in a cuvette to measure temperature of the leaf without conducting excessive heat; (2) a thermistor in the cuvette chamber; and (3) a moisture sensor in the chamber. The moisture signal automatically controls a magnetically operated bypass valve from a source of air flowing through the cuvette chamber so that the moisture remains constant while the flow rate of the air is varied. The flow rate is measured in a flow meter having two laminar paths in series, composed of equal-length equal-diameter tubes but differing in the number of tubes, with the flow rate being measured in a different one of two tubes in each path for different scale measurements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.