Mehrwegeschalteinrichtung für Durchflussmengen

摘要

A multi-stage type flow rate switching device is provided which simplifies switching of flow paths and which rarely causes erroneous operation. The multi-stage type flow rate switching device includes a constant flow rate path 2 and a variable flow rate path 3 arranged in parallel between a liquid medicine flow inlet port 1 and a liquid medicine flow outlet port 4 where the variable flow rate path 3 can change the flow rate by means of a three-way stopcock 33. Although the flow rate can be switched in four stages when one variable flow rate path 3 is arranged as shown by Fig. 1, the flow rate can be switched in further multi-stages by providing two or more of the variable flow rate paths 3 .