High-Viscosity Valves

These custom-designed rotary valves have helped a manufacturer of DNA analysis instruments solve a seemingly intractable problem. The instrument, which uses very high viscosity fluids, needed inert valves with sufficient shear force to cut through the fluid, acting as shut-off valves. The solution was a 1-mm-bore custom-designed rotary valve with a stainless steel rotor for torsion strength, a Tefzel liner for chemical inertness, and a PEEK body for rigidity. The shape of the rotor was carefully profiled to give a clean cut through the fluid, ensuring an instant start/stop of the flow. The valve can operate up to a pressure of 1,000 psi and is controlled by TTL or RS-232 protocols. Optical encoders are used to provide precise port positioning, enabling maximum flow of the fluid every time.