Patent ID: 7574901

Claim:
A flow path switching valve, fitted for a high performance liquid chromatography (HPLC) comprising a trap column, a condensation infusion pump, a sample injection portion, an analytical column and an analysis infusion pump, for switching ports connected to rotor slots by rotating a rotor on which a plurality of the rotor slots is formed, wherein one of the rotor slots is a long rotor slot with a length sufficient for connecting three ports at the same time, and the rotor is interchanged between one position, at which the long rotor slot connects three ports respectively of the trap column, the analysis infusion pump and the analytical column, and another position, at which the long rotor slot connects merely two ports respectively of the trap column and the analysis infusion pump or respectively of the analysis infusion pump and the analytical column, wherein the trap column, the analysis infusion pump and the analytical column are connected and a pressure difference between the trap column and the analytical column is eliminated, when the long rotor slot connects the three ports respectively of the trap column, the analysis infusion pump and the analytical column.