Moisture sensing switch
US4838296A · kind A · utility
Inventor
Key dates
| Filing date | May 2, 1988 |
| Grant date | Jun 13, 1989 |
| Priority date | — |
| Expiry date | May 2, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/86389
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A sensor disposed in the ground has a characteristic which changes generally predictably in relation to the moisture content of the ground. A signal is produced by a circuit during a period of energization whenever the characteristic of the sensor is at or beyond a threshold. The signal, once produced, is held during said period of energization, the energy being provided by a source of periodic energization for a solenoid driven water valve. A gate passes the periodic energization to the solenoid whenever said signal is present. When the periodic energization ceases, said signal ceases and the water valve closes. If the characteristic of the sensing element is not at or beyond said threshold during a period of energization, said energization is not gated to the water valve solenoid and the water valve remains closed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.