Patent attributes
An autosampler for high-performance liquid chromatography (HPLC) with a high-pressure injection valve (1, 2) having improved life, particularly in high pressure operation. The geometry of the valve components and the connections of the high-pressure injection valve are provided such that the switching processes do not take place in a deleterious direction. The grooves in rotor (2) and/or the port opening cross sections (131, 151) in stator (1) and the rotational direction are selected such that fluid flows from grooves under high pressure in the direction of narrow, substantially pressure-free ports are avoided. This applies in particular to the switching process from INJECT to LOAD, since the sample loop contains a relatively large dead volume of compressed fluid. In addition, the valve can be controlled according to the invention in such a manner that an appropriate time is available for reducing harmful or undesired pressure differences.
