Control system for simulated moving bed chromatography
The present invention provides devices and methods for micro-scale simulated moving bed chromatography (SMB) for continuous preparation of analytic quantities of highly pure fractions of target molecules. The present apparatus and method of the invention is adapted in a preferred embodiment to separations by affinity chromatography involving three discontinuous liquid flow loops. An alternative embodiment of affinity chromatography utilizes standard SMB operating under isocratic conditions.
1. A control system for controlling the state of a plurality of valves formed in a valve block formed by a pressure manifold, a fluid transfer plate having grooves formed therein, and a flexible diaphragm positioned between the pressure manifold and the fluid transfer plate such that varying pressure through the pressure manifold at a plurality of points thereon distorts the flexible diaphragm to block or un-block the grooves in the fluid transfer plate, thereby forming valves, comprising:
(a) a plurality of solenoids for controlling the pressure provided through the pressure manifold at the plurality of points thereon;
(b) a computer programmed to provide a user interface to allow a user to select states of the plurality of valves and to convert the selected valve states into a bit stream;
(c) a storage device comprising series connected shift registers in which the bit stream is shifted downstream in the series connected shift registers until sufficient shift registers are loaded with the bit stream representing the desired state for all the valves; and
(d) a control circuit connected to the computer to receive the bit pattern therefrom and to load the bit pattern into the storage device.
2. A method for controlling the state of a plurality of valves formed in a valve block formed by a pressure manifold, a fluid transfer plate having grooves formed therein, and a flexible diaphragm positioned between the pressure manifold and the fluid transfer plate such that varying pressure provided through the pressure manifold at a plurality of points thereon distorts the flexible diaphragm to block or un-block the grooves in the fluid transfer plate, thereby forming the valves, comprising:
(a) providing a plurality of solenoids for controlling the pressure provided through the pressure manifold at the plurality of points thereon in response to input signals provided thereto;
(b) providing a user interface in a computer system to allow a user to select states of the plurality of valves;
(c) converting in the computer system the selected valve states into a bit stream;
(d) loading the bit stream into a storage device comprising series connected shift registers in which the bit stream is shifted downstream to the series connected shift registers until sufficient shift registers are loaded with bit stream representing the desired state for all the valves; and
(e) simultaneously triggering the shift registers to present the loaded bit stream from the shift registers to the solenoid inputs.