Liquid chromatograph
US4752385A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 17, 1986 |
| Grant date | Jun 21, 1988 |
| Priority date | — |
| Expiry date | Sep 17, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2030/326
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The liquid chromatograph comprises a multiple piston pump (1) which is arranged so that the delivery strokes of two pistons overlap to such an extent that for all designed liquid delivery pressures and compressibilities no period exists when no piston is delivering liquid. Thus for all other than worst case conditions there are periods in each pump cycle when two pistons are delivering liquid. The start of these periods is detected by the pressure increase produced at the outlet of the pump and measured by a pressure transducer (5). The output of the pressure transducer is fed via path (14) to a motor drive circuit (10) which controls a motor (4) which drives the pump (1) via a shaft (3) so that the speed of advance of the pistons is halved until one of the pistons ceases delivery. Consequently a relatively pulse free liquid flow is produced by the pump with a relatively simple motor speed control system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.