Valve
A sample injector includes a rotary valve element with a straight passageway through it, which element may be rotated to connect a port communicating with a source of solvent with a port communicating with an inlet to a column. Another passageway connects two adjacent ports. The valve element may be rotated to one position in which it provides a straight path for sample to be injected, a second position in which it provides a path that connects a source of purge gas to the chromatographic system and a third position in which it provides a path that connects solvent to the column for preconditioning.
1. A sample injection valve for preparatory liquid chromatography comprising:
at least one rotor;
actuator means for moving the at least one rotor from position to position;
a plurality of output ports;
each of said output ports being alignable with a corresponding opening in said at least one rotor;
said at least one rotor having a straight smooth passageway through its center whereby ports spaced 180 degrees from each other may communicate when the at least one rotor is in a first position;
said at least one rotor having a connecting channel having a first channel end and a second channel end;
the first channel end of said connecting channel communicating with a third port and the second channel end communicating with a fourth port;
said third and fourth ports being between a first port and a second port whereby said at least one rotor rotates from position to position, said ports spaced 180 degrees from each other communicate with each other and adjacent ports communicate with each other; wherein said first port is adapted to communicate through a sample holder with a source of chromatographic solvent and said second port is adapted to communicate with a chromatographic column through a passageway that extends from said sample holder to said chromatographic column;
said passageway being a smooth passageway.
2. A sample injection valve in accordance with claim 1 wherein said third port is adapted to communicate with a source of purged gas and said fourth port is adapted to communicate with said communication for purging thereof.
3. A sample injection valve in accordance with claim 2 in which said third port in a second rotary position is adapted to communicate with said source of chromatographic solvent and said fourth port in another position is adapted to communicate with said chromatographic column.
4. A sample injection valve in accordance with claim 3 further comprising a tubular stator, said tubular stator having a cylindrical opening adapted to rotatably receive said at least one rotor and having cylindrical bores spaced around the tubular stator periphery; whereby rotation of the at least one rotor aligns at least one cylindrical bore of the cylindrical bores spaced around the tubular stator periphery with an opening and a corresponding smooth channel in said at least one rotor.