Method for the automatic control of a process variable
Abstract
Abstract The invention is drawn to a method for the automatic control of a process variable particularly a hazardous variable such as the flow rate of an inflammable gas, e.g. oxygen. Signals representing the variable are fed to a computer whereby they are lagged before being compared with subsequent signals. The difference between the lagged and unlagged signals may then be compared with a fixed signal representing a preset critical value to the variable. When this latter value is exceeded remedial action is taken. Preferably the lagged signal is emitted in exponential form, so permitting controlled increases in the variable to be made more readily. The invention is of particular use in systems involving gas recirculation in which an accidental increase in gas flow rate is magnified by the recirculation system.
Inventors
- 👤 James Spence Anderson
Bibliographic Details
Claims Analysis
Total Claims: 2References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-07-19 | 1975-01-18 | 1975-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-19 | 1979-01-18 | 1979-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-19 | 1983-01-18 | 1983-07-20 | $7700.00 | Window Closed / Lapsed |