Thermostat
US4240077A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 2, 1978 |
| Grant date | Dec 16, 1980 |
| Priority date | — |
| Expiry date | Mar 2, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B17/06
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A thermostat monitoring and controlling the temperature of produce ripening within an enclosure and featuring a bridge circuit sensing errors between the actual and desired temperatures in which the desired temperature is selected directly in units of degrees. A bridge amplifier having feedback maintains the bridge in electrical balance to avoid errors due to changes in bridge component self heating. An error detection circuit having a single control simultaneously selects upper and lower error limits centered on the desired temperature, in units of degrees. The circuit indicates whenever the actual temperature goes outside these limits. An alarm circuit indicates a temperature error or a power failure in the thermostat at the thermostat and at a remote location. This circuit utilizes an alternating current source which activates current direction-dependent indicators operating on alternate half cycles. Electrical isolation of the temperature monitoring circuitry from the circuitry controlling heating, cooling and fan equipments is provided by coupling a signal indicating a temperature error through a single electrically isolating interface to eqiupment selection and control circui…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.