Device for combining two fluid streams

• US 20040232366A1
• Filed: 05/06/2004
• Published: 11/25/2004
• Est. Priority Date: 05/19/2003
• Status: Active Grant

• Current Assignee: Oakland University
• Original Assignee: Oakland University
• Inventors: Seeley, John V.
• Granted Patent: US 7,247,189 B2
• Time in Patent Office: Days
• US Class Current: 251/12
• CPC Class Codes: G01N 2030/025 Gas chromatography
• CPC Class Codes: G01N 2030/383 by using auxiliary fluid
• CPC Class Codes: G01N 30/20 using a sampling valve
• CPC Class Codes: G01N 30/463 for multidimensional chromatography
• CPC Class Codes: G01N 30/465 with specially adapted interfaces between the columns
• CPC Class Codes: G01N 30/466 with separation columns in parallel

Abstract

A fluidic switching device is particularly for use in chromatography is described. The device allows a rapid switching between chromatographic columns; particularly, in gas chromatography.

Claims

1. - A fluidic switching device which comprises:

(a) a valve comprising a single inlet adapted for receiving a carrier fluid and two outlets wherein the valve is actuated by an actuator for cycling between each of the outlets;

(b) first and second tubular conduits leading from the valve to each of two separate inlets into a common first union with an outlet between the inlets;

(c) third and fourth tubular conduits as a connection between the first and second tubular conduits; and

(d) a second union between the third and fourth tubular conduits adapted for flow between arms of the union and adapted so that a fluid can flow into two arms from a leg of the second union, wherein the device is constructed so that fluid flow is greater in the first and second conduits than in the third and fourth conduits such that when the flow is switched in the valve to the one of the first or second conduits a fluid material introduced in the second union is temporarily accumulated in the opposite first or second conduit from the third or the fourth conduit which is subsequently flushed from the opposite first or second conduit by the carrier fluid flowing in the opposite first or second conduit upon switching of the valve from one of the outlets from the valve to the other outlet from the valve.

3. - A chromatographic separator apparatus which comprises:

(a) a fluidic switching device as in claim 1;

and

(b) at least one chromatographic column connected to the leg of the second union;

wherein the device is adapted to move units of the fluid material mixed with the carrier fluid into the column between units of the carrier fluid alone.

4. - The apparatus of claim 3 wherein the device is mounted inside an oven with the valve on an outside of the oven and insulated from the inside of the oven.

5. - The device of any one of claims 1, 2, 3 or 4 wherein the conduits comprise fused silica tubing over which the fluid flows.

6. - The device of any one of claims 1, 2, 3 or 4 wherein the valves, conduits and unions are adapted for a gas as the fluid.

7. - A method for fluidic switching which comprises:

(a) providing a fluidic switching device as in claim 1;

and

(b) introducing the carrier fluid into the inlet of the valve and the fluid material into the inlet into the second union wherein the valve delivers units of the fluid material mixed with the carrier fluid between units of the carrier fluid to the outlet of the first union.

8. - The method of claim 7 wherein the outlet of the first union is connected to at least one chromatographic column.

9. - The method of claim 7 or 8 wherein the fluidic device except for the valve is heated inside an oven.

10. - The method of claim 7 or 8 wherein the fluid material and carrier fluid are a gas.

11. - The method of claim 7 or 8 wherein the first and second conduits and the third and fourth conduits have identical cross-sections along their length.

12. - The method of claim 7 or 8 wherein the ratio of fluid flow rate of the carrier fluid to fluid material is between about 30 to 1 and 10 to 1.

13. - The device of claim 1 with a purging flow line between the first and second tubular conduits before the first common union.

2. - A fluidic switching device which comprises:

(a) a valve comprising a single inlet adapted for receiving a carrier fluid and two outlets wherein the valve is actuated by an actuator for cycling between each of the outlets;

(b) first and second tubular conduits of equal internal flow resistance leading from the valve to each of two separate inlets into a common first union with an outlet between the inlets;

(c) third and fourth tubular conduits of equal internal flow resistance as a connection between the first and second tubular conduits; and

(d) a second union between the third and fourth tubular conduits adapted for flow between arms of the union and adapted so that a fluid can flow into two arms from a leg of the second union, wherein the device is constructed so that fluid flow is greater in the first and second conduits than in the third and fourth conduits such that when the flow is switched in the valve to the one of the first or second conduits a fluid material introduced in the second union is temporarily accumulated in the opposite first or second conduit from the third or the fourth conduit which is subsequently flushed from the opposite first or second conduit by the carrier fluid flowing in the opposite first or second conduit upon switching of the valve from one of the outlets from the valve to the other outlet from the valve.

14. - The device of claim 2 with a purging flow line between the first and second tubular conduits before the first common union.