Digital control for rapid refill of a liquid chromatograph pump
US4643649A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 11, 1985 |
| Grant date | Feb 17, 1987 |
| Priority date | — |
| Expiry date | Feb 11, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2030/326
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A liquid pump motor control for a liquid chromatograph. The control detects when the pump needs to be refilled. Then, the pump motor is accelerated at a first rate for a given number of pulses. Then the motor is accelerated at substantially its maximum rate until a selected maximum speed is reached. Thereafter the speed is maintained at its maximum until the time calculated to begin deceleration. The motor is then decelerated substantially at its maximum deceleration rate until the speed is close to the final desired speed. Then deceleration occurs at a slower rate for a fixed number of pulses. The number of pulses applied to the stepping motor from the beginning of acceleration until the end of deceleration is constant regardless of the beginning or ending pulse rates.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.