Bidirectional flow reaction system for solid phase synthesis

Flow control mechanisms control the direction and flow rate of synthesis reagent through one or more synthesis reaction vessels for automated solid phase synthesis. Selectable, known, and reproducible positive or negative pressure differentials (−5 to +10 psi) accomplish controlled, bidirectional (forward and reverse) flow of synthesis reagents through synthesis media contained within the reaction vessels. Venturi-based vacuum apparatus, valves, electronic pressure regulators and compound digital pressure gauge, can be added to automated solid phase synthesis instruments to provide, control, and monitor known, selectable, reproducible negative and positive pressures to one or both valve sealable and un-sealable ends (inlets and outlets) of the reaction vessel as needed to generate and reverse said pressure differentials between the opposite ends of said synthesis reaction vessels, yielding controlled forward and backward flows of synthesis reagents through the synthesis media.