The present invention is an apparatus and fluid delivery system for automated assays. The apparatus, for example, may be used for western blotting that uses flow lines for multiple reagents. In one embodiment, the present invention comprises a tray base with one or more fixed or disposable trays for testing samples, multiple flow lines, and multiple valves and the system is used for automatic controlled delivery of different fluids from supply vessels to different trays and discharges them to designated reservoirs or sewage system with minimum of operator actions. The system may include air line to assist supply and discharge the fluids and also coupled with measuring vessels with adjustable volume and valves adapted to interface with a valve operating unit with drive means. The system is controlled by a programmable electronic device that controls the preset values and sequences of valves operation to deliver or discharge the selected fluids in any one or more of plural fluid input ports individually or all together simultaneously, by a set of programmable pinch valves assemblies that pinching or releasing multiple of elastomeric flow conduits, used as a pinch member. The valve operating unit may, in one embodiment, be a single drive unit to control all valve assemblies or, as alternative embodiment, attached to the housing individual mechanism.