Liquid passage switching device

摘要

A liquid passage switching device in which switching of a liquid takes place entirely within another liquid so that no bubbles can be entrapped in the liquid while it is being switched between passages. Plural passages are formed in a head one side of which is sealed with a container having ports which allow a first liquid to flow in and out. A generally U-shaped connecting tube is mounted on a supporting plate and ends of the connecting tube are rotatable by the supporting plate along a circle in which the passages in the head are formed. The openings of the connecting tube are engagable with and disengagable from the passage in the head by moving the supporting plate outward, rotating the supporting plate, and then moving the supporting plate back towards the head and engaging the openings of the connecting tube with the desired passages.