This rotary valve is actuated by an hs422 servomotor. The stator has six 0,6mm dia in/out ports, while the com port is housed onto the rotor, coupled via a rubber gasket. The dead volume of the valve is zero. It will be integrated into a micro liquid analyzer. The under pressure behavior of the unit was surprisingly good, considering that is has been designed- and will work to- in a low pressure hydraulic environment. Finally the carryover between ports was also surprisingly low and easily approximable to zero as far as the operative setup is concerned. Typically the cost of a similar commercial unit, with a very low dead volume, would be in the order of many hundreds of $. I'm happy because my unit's main cost was related to a 10 $ servomotor, and the dead volume is exactly zero.

Valve during testing below.