Low noise back pressure regulator for supercritical fluid chromatography

摘要

A drive mechanism for back pressure regulator used in liquid chromatography, supercritical fluid chromatography, or supercritical fluid extraction allows very fine automated control over a very wide range of pressures by combining a linear actuator compressing a spring, pushing a pin. The nozzle assembly of the regulator comprises a flow through chamber containing a diaphragm and a seat, in which the pin pushes the diaphragm against the seat, together with an upstream pressure sensor and electronic feedback control to the motor of the actuator. The BPR of the embodiments exhibits high pressure stability and extremely low pressure noise, even at moderate to high pressures. The exemplary BPR can be use at either constant pressure or to generate pressure programs where the pressure is varied versus time. Further, the nozzle assembly has a field-replaceable head, requiring no mechanical adjustment on replacement.

主权项

1. A device for a back pressure regulator, comprising:
a nozzle insert comprising; an outlet flow channel that can receive an outlet flow tube and an inlet flow channel that can receive an inlet flow tube; a seat, near an end of said insert, such that said seat can be in fluidic communication with said outlet flow channel; and a nozzle body at least partially receiving said nozzle insert and said seat; and a diaphragm having a first surface positioned adjacent to said seat wherein said nozzle body constrains a circumferential edge of said diaphragm.