Control and alarm system for freezer case temperature
US4283921A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 25, 1980 |
| Grant date | Aug 18, 1981 |
| Priority date | — |
| Expiry date | Apr 25, 2000 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF25B2400/22
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The temperature within a freezer case or refrigeration compartment is operatively determined and controlled by a control system employing a microcomputer which operatively controls a refrigeration system associated with the freezer case. A sensing element is operatively connected to the microcomputer for supplying a signal representative of the freezer compartment temperature. Temperature selector switches establish upper and lower limits of a desired range of temperatures for the freezer case and another selector switch establishes an alarm condition temperature limit. The microcomputer follows a program of comparing the compartment temperature to the upper limit, the lower limit and the alarm condition limit. During normal operation, the microcomputer also controls a refrigerant valve to regulate the compartment temperature within the desired range. If the compartment temperature elevates to the alarm condition limit, the microcomputer energizes a first alarm. If the alarm condition remains for a predetermined time period, a second emergency alarm is energized.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.