Apparatus and method for liquid chromatography
US4775481A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 10, 1987 |
| Grant date | Oct 4, 1988 |
| Priority date | — |
| Expiry date | Aug 10, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2030/326
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
To stabilize flow rate in a single-stroke, syringe-type high pressure pump at a constant value after turn-on, a control system increases the pump speed until equilibrium conditions are reached and then pumps at the present rate. In one embodiment, the system is operated in a constant pressure mode under the control of a feedback system to a point at which the pressure is estimated to provide the desired flow rate, with feedback being provided from a pressure measurement and from a flow rate measurement. The feedback from the flow measurement is increased logarithmically with the rate of pumping prior to being compared with the pressure error signal and the comparison between the previous error signal and the logarithmic flow rate signal is used to control the speed of pumping.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.