Instructions for CO 2 Cold Trap System Part No. 093346
Introduction Congratulations on your purchase of the SGE CO 2 Cold Trap System. Please take time to read the instructions in this manual carefully to ensure trouble-free operation of your cold trap. The SGE Cold Trap System uses liquid CO 2 to control the flow of CO 2 to a low thermal mass cold trap through a pneumatically actuated valve. This valve fits directly onto the cold trap tee (item 1, Diagram 1) and is designed to shut-off liquid CO 2 flow at a pressure of approximately 1400psi (9500kPa). The pneumatic valve is actuated using compressed air (or other suitable gas such as nitrogen) at a pressure of 50 psi. The SGE cold trap is designed for cooling with CO 2 using the Joule-Thompson principle. The trap has been designed for efficient cooling by ensuring the capillary column is close to the point at which CO 2 undergoes phase transformation from liquid to gas. Also, the volume between the valve and the restrictor must be minimal to ensure a sharp cut-off in the CO 2 flow through the restrictor. For further information and ordering of spare parts, please visit our web site at : www.sge.com
Installation Loosen the nut (2) and remove the cold trap tee (1). Select a suitable location inside the GC oven where the capillary column can be passed through the trap and the input leg of the trap can be passed through the oven wall. Also ensure there is adequate room on the outside of the oven to mount the valve. Drill a 1/8" hole through the oven wall for the cold trap input leg. Find a suitable position to fix the valve mounting bracket (6) onto the outer oven wall of the GC. Sheet metal screws are provided for this purpose. The bracket positioning may be adjusted by first loosening the grub screws (7) with the Allen key provided. A 1/16" stainless steel line (5) should be run between the pneumatic valve where it is connected using the nut (8) and the Manual Toggle Valve (MTV-3), (Diagram 3). On the switching valve, the line is connected to the position labelled To Pneumatic Valve. For these connections Vespel sealing rings should be used. A 1/16" stainless steel line (9) is run from the carbon dioxide cylinder to the valve. The inside diameter of the stainless steel tubing provided is 0.8mm. Smaller tubing than this or any restrictions in the line, will lead to significant losses in cooling efficiency. The line (9) is connected to the valve via a filter (3). The connections should be made using Vespel Sealing Rings (Part No. 072653) and the stainless steel nut (4). Mount the manual valve (MTV-3) in a convenient place on a panel of the GC. The actuating gas should be connected to the MTV-3 valve as shown in Diagram 3. For correct operation of the valve, it is essential not to insert the stainless steel tubing too far as it may damage the valve poppet. Pass the section of the capillary column, which requires cold trapping, through the cold trap tee (item 1, Diagram1).
Operation The cold trap operation is initiated by simply switching the MTV-3 valve which opens the cryogenic valve. The flow of liquid carbon dioxide should be started a short time (30-60 seconds) prior to the arrival in the capillary column of the compounds to be trapped. Compounds with boiling points equivalent to C 7 - C 8 can be trapped (and held in place in the trap) at an oven temperature up to 200ºC. If colder temperatures are required for successful cold trapping, liquid nitrogen will be required as the coolant source (see note below). When the flow of liquid carbon dioxide to the cold trap is stopped by turning off the actuating air to the pneumatic head, the cold trap heats up quickly and uniformly due to its low thermal mass design. NOTE: This liquid CO 2 cryogenic valve and cold trap tee must not be used with liquid nitrogen as dangerous pressures would build up.
Diagram 1. Liquid CO 2 Valve Assembly with Cold Trap Tee 5 8 7 4 3 9 Union 2 6 7 1 Note: Items 2, 4 and 8 contain Vespel Sealing rings (also refer to Diagram 2)
Description Item Part No. Re-order Description Pack size 1 093348 1 CO 2 Cold Trap Tee 2 103404 5 1/16" Brass Nut (Nickel Coated) 3 0933424 1 50 micron filter for CO 2 4 103403 5 1/16" Stainless Steel Nut 5 0624160 5 meter length 1/16" Stainless Steel Tubing 6 Mounting Bracket 7 Grub Screw 8 103404 5 1/16" Brass Nut 9 0624160 5 meter length 1/16" Stainless Steel Tubing Note: The Liquid CO 2 Valve Assembly can be purchased as a separate part (Part No. 0933423). This part number excludes the cold trap tee.
Other Packing Contents Part No. Qty Description 093218 1 Manual Toggle Valve (MTV-3) 1236101 1 Seal Removal Tool 1 1/16" Allen Key 072653 10 Vespel Sealing Rings 2 Screws 1 1/4-5/16 Spanner 1 Replacement Valve Seat 1 Valve Seal Kit consisting of 2 x PTFE seals and 1 x O-ring (contained in valve head assembly)
Diagram 2. Exploded View of Liquid CO 2 Valve Assembly (Part No. 0933423) Valve head assembly 1/16" Brass Nut Vespel Sealing Ring Needle Top Bracket Spring Needle Tube Guide PTFE seal Vespel Sealing Ring Valve Body 1/16" Stainless Steel Nut CO 2 filter Valve Seat Union Vespel Sealing Ring 1/16" Brass Nut
Diagram 3. Manual Toggle Valve (MTV-3) Mount the MTV-3 valve in a convenient place in the panel to the GC. The actuating gas sources should be connected to the inlet of the valve as shown below. For correct operation of these valves, it is essential not to insert the stainless steel tubing too far because this may damage the valve poppet. Cooling On To Pneumatic Valve From Gas Supply Cooling Off
Contents Seal Removal Tool Allen Key CO 2 Valve Cold Trap Tee Bracket 2 x 8G x 1/2" Self Tappers Vespel Sealing Rings Spanner MTV3 3 meters - Stainless Steel Tubing 2 - PTFE Seals 1 - Small O-Ring 1 - Valve Seat
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