Siemens GC..M.. Manual de instalación descargar pdf (Pagina 28)

Sampling System Installation, Continued

Transport Tubing

Refer to Application Drawing Package, Block Diagram Utility Connections sheet.

Gas Samples

Transport tubing is typically ¼“ (6.35 mm) OD for gas samples, and ⅜“ (9.53 mm) OD for liquids. Leave

enough extra tubing to make sure it will reach the connection points. The stainless steel tubing must be

very clean and dry. If in doubt, flush it with acetone and dry it with an inert gas. Cap the open tubing ends

to prevent contamination. Plan to transport gases at as low a pressure as possible, typically 5 to 15 psig

(35 to 103kPa) or 5 psig (35 kPa) above the sample return pressure. The analyzer requires 5 psig (34

kPa) of differential pressure. The pressure should be set at the probe site.

Liquid Samples

Liquids should have a minimum of 25 psig (172-kPa) differential between the sample take-off and return

points, allowing for a minimum liquid flow of ½ U.S. gal/min (1.9 L/min). Sample lines of ⅜“ (9.53 mm) OD

more than 100-ft. (30.5 m) long may require more than 25 psig (172-kPa) differential.

Heat Tracing

Refer to Application Drawing Package, Block Diagram Utility Connections sheet.

Some sampling systems require heat tracing of the transport tubing. If heat tracing is required, it will be

noted on the Block Diagram Utility Connections sheet. It is essential that none of transport tubing be

exposed to ambient conditions. The tubing must be continuously traced, insulated, and weather

protected. Steam tracing must be continuously sloped downward for draining any condensate, and it must

have condensate traps at low points and at least every 50 ft. (15.2 m). All joints and valves must also be

heat traced, insulated, and weather proofed. The tubing must be continuously traced through the analyzer

house wall and up to the edge of the sampling system cabinet. If steam tracing is used, it must be at the

pressure recommended on the Block Diagram Utility Connections sheet. If electrical tracing is used, it

must be safe for the hazardous area location. It must also be of the wattage recommended on the Block

Diagram Utility Connections sheet.

Sample Wetted Parts

Each Maxum II system is designed by Siemens with the customer’s specific application needs in mind.

This includes the design of all parts coming into contact with the sample. Each system is designed such

that all sample wetted parts (e.g. valves, fittings, tubing, etc.) are compatible with the sample materials.

This compatibility must be taken into account if any changes are to be made to the sample composition.

Refer to the Application Drawing Package for more information regarding the materials for which a

specific analyzer is designed.

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Siemens GC..M.. Manual de instalación Pagina 28