A pair of new valves from Burkert Contromatic Corp., Irvine, Calif., uses flipper actuators and flexible diaphragm materials to let them handle high pressures and low internal volumes.
The low dead-volume, low-carryover valves eliminate cross contamination, making them well suited for analytical and medical applications. The valves (Type 6127/6128 and 6607/6608), with orifice sizes to 3 mm, can be configured as three-way valves with all three ports in the base, or as two-way, normally opened and normally closed valves. A stainless-steel plate insulates the actuator from the coil, preventing the coil from overheating. The flipper design, which is relatively frictionless and back-pressure tight, resists clogging and sticking, giving the valves a long, accurate, and reliable life. The valves maintain fast opening and closing times (15 to 25 msec) over fluid temperatures ranging from 0 to 236F. Operating fluid pressures can be as high as 42 psi on the Type 6607/6608 and up to 140 psi on the Type 6127/6128.
Type 6127/6128 valve use ethylene propylene diene monomer (EPDM) or fluoroelastomer diaphragms to isolate fluids from metal parts, preventing metal-to-fluid contact that can cause abrasion, contamination and corrosion. Type 6607/6608 valves, on the other hand, use perfluoroelastomer diaphragms to completely separate the actuator and fluid for high purity and easy maintenance.