Sample valve with integral sample shut off function for chromatograph
A multiple port valve integrated with the function of the sample shut off valve is disclosed. The integration of the sample shut off function eliminates extra plumbing and labor costs associated with a separate sample shut off valve. Additionally, the multiple port valve integrated with the function of the sample shut off valve provides a shorter equilibration time and less tubing volume.
1. A multiple port valve apparatus for injecting a sample to be analyzed in to a column of a chromatograph that analyzes samples, said multiple port valve apparatus comprising:
a plurality of ports, at least one of said ports receiving said sample to be analyzed by said chromatograph;
a plurality of passages connecting said plurality of ports that transmit said sample between said plurality of ports; and
a separately controlled passage that is independently controllable from said plurality of passages that responds to independent control;
wherein the separately controlled passage is configured to integrate a sample shut off valve function by controlling an inlet of the sample to said column of said chromatograph.
2. The apparatus of claim 1 wherein said multiple port valve apparatus is a ten port valve.
3. The apparatus of claim 1 wherein said multiple port valve apparatus is a six port valve.
4. The apparatus of claim 1 , wherein said sample is a vapor and said separately controlled passage effects said sample shut off valve function by controlling an inlet of said vapor.
5. The apparatus of claim 1 , wherein said separately controlled passage is selected such that a time period for equilibrating a pressure of said sample is optimized.
6. A method for switching a multiple port valve that transmits a sample to be analyzed to a chromatograph that analyzes said sample valve having an independently switched sample flow passage integrated therein for effecting a sample shut off valve function, said method comprising the steps of: inletting a sample to be analyzed into a first port of said multiple port valve; transmitting said sample inlet into said first port to said sample flow passage; and controlling said sample flow passage independently from other passages of said multiple port valve to control a flow of said sample through said sample flow passages to thereby effect said sample shut off valve function.
7. The method of claim 6 , further comprising the step of selecting a volume of said sample valve such that a time period for equilibrating a pressure of said sample is optimized.
8. The method of claim 6 , further comprising the steps of transmitting said sample inlet to said first port to a second port through said sample flow passage to a third port and transmitting said sample at said third port to a fourth port where the sample is vented.
9. The method of claim 8 , further comprising the step of blocking the flow of said sample from said first port to said second port.