Microprocessor based control system and method providing better performance and better operation of a shipping container refrigeration system
US4663725A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 15, 1985 |
| Grant date | May 5, 1987 |
| Priority date | — |
| Expiry date | Feb 15, 2005 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF25B2600/0252
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
A microprocessor based system monitors and controls a transport refrigeration system having a two speed compressor coupled to a condenser and an evaporator and further having two speed condenser and evaporator fans, a refrigerant modulating valve, and heater means to cool or heat a served space. A keypad is provided for operator entry of the temperature setpoint and for display selections. Return air and discharge air temperature sensors provide signals to the microprocessor for temperature control. The microprocessor is programmed to sequence or control the compressor, the fans, the modulating valve and the heater means for temperature control in accordance with one of four stored algorithms. One of the temperature sensors is used for control, and if it is detected to have failed automatic switchover is made to use of the other temperature sensor for temperature control. Various input signals from the refrigeration system and from the microprocessor hardware are processed by the microprocessor to provide a data log and data for display and to detect system faults for fault history storage and for protective control action.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.