Tensiometer with remote sensing unit
US3939699A · kind A · utility
Inventor
Key dates
| Filing date | Sep 27, 1974 |
| Grant date | Feb 24, 1976 |
| Priority date | — |
| Expiry date | Sep 27, 1994 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N7/14
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A tensiometer having a vacuum gauge which is connected to a sensing unit including a ceramic cup, which is located remote from said gauge, by a conductor in the form of a capillary tube. A second capillary bleeder tube communicates with and leads from the ceramic cup and has a second end which is located below the level of the other end of the conducting tube, so that when said second end of the bleeder tube is exposed, the escape of air therefrom can be visually determined, during purging of the device, so that after all air has been removed from the tubes, the tensiometer can be sealed. The end of the conducting tube disposed remote from the ceramic cup is connected to a lower end of a sight glass, to the upper end of which is connected the gauge, so that when air has been removed from the device and the sight glass, tubes and cup are filled with water and sealed, a vacuum will be created in the system as the moisture in the earth surrounding the cup diminishes, to register this reduced moisture condition on the gauge.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.