Corrosive fluid applications always pose challenges for designers. In the miniature fluid control arena, a company has recently developed a solenoid valve with micro-dispensing capability for solvents (such as widely used dimethyl sulfoxide (DMSO)) that is equipped with a precision zirconia ball and seat that replaces the traditional elastomeric rubber seal.
Marketed by the Lee Co. under the Hard Seat VHS Micro-Dispense Valve brand range, the new valve is said to offer precise, repeatable, non-contact dispensing in the nanoliter-to-microliter range, and its high chemical resistance is reportedly well suited for DMSO and other fluids that typically react with elastomeric seals. In traditional valves, a plunger is used with an EPDM (ethylene propylene diene monomer) rubber, fluorocarbon rubber (Viton from DuPont) or perfluoroelastomer (Chemraz from Green, Tweed & Co.) seal on a stainless steel seat.
The threaded connection that is employed as the inlet is made from polyetherertherketone (PEEK) resin, while the outlet port can also be molded from PEEK.
The micro-dispensing valve is likely to find applications in medical and scientific instruments. Typically, it operates with a very low pressure of 5 psig and a 0.25-ms pulse duration, and dispense volumes down to 10-20 nL can be achieved, according to Mike Stott, general manager at Lee Co. Furthermore, the compact size (39 to 45 mm long by 5.6 mm dia) of the valve allows it to fit directly over 96 well plates.
The Hard Seat VHS valve is available in a number of port configurations, allowing connections to Lee Co.’s 062 MINSTAC fittings and press on tubing. The 062 MINSTAC outlet can be used with Lee Co.’s 062 MINSTAC tubing or atomizing nozzles. Custom configurations and voltages can be supplied for specific applications.
Lee Co. also supplies spike and hold modules that can be used to control the valves during prototyping, and also micro-dispensing starter kits that include most of the components necessary for prototype and development work.
Lee Co. has offices in Westbrook, Conn.; Los Angeles; Dallas; Chicago; Southfield, Mich.; and Clearwater, Fla.