A sample cylinder is required for every GSM system and should be ordered separately when purchasing a new GSM. Various configurations of sample cylinder assemblies, defined as Grab Sample Cylinders (GSC), are available. The options available for GSC assemblies include:
- Five standard cylinder sizes (150, 300, 400, 500, & 1000 cm3 )
- Multiple cylinder and valve material options
- With or without purge bypass tube
- Choice of quick connects
- Outage tubes, rupture discs, and handles
- Cylinder treatment/certification • Stem and body protectors
- PTFE coated inner wall, SilcoNert® coating, or electropolished inner diameter
- Cylinders with DOT, TC or TPED certification (see Sample Cylinders, Accessories, and Outage Tubes, MS-01-177, and Swagelok Products Compliant with the Transportable Pressure Equipment Directive (TPED), MS-02-193, for additional information.)
- Valves with TPED certification
Outage tubes provide a vapor space of the desired volume in cylinders containing liquefied gases, so that the liquid in the cylinder can expand if the temperature increases. Without enough vapor space, a small temperature increase can cause the liquid to expand and increase the pressure dramatically. See local regulations and other appropriate guidelines for safe filling limits for your application.
Outage is the vapor space in the cylinder expressed as a percentage of the total volume of the cylinder. % outage = (vapor space/total volume) × 100 The cylinder is held vertically with the outage tube at the top, as shown. The length of the outage tube determines the amount of vapor space. Sampling methods and the use of the outage tube are described in technical publications such as ASTM D1265, Standard Practice for Sampling Liquefied Petroleum (LP) Gases (Manual Method).
Note: Only certain components are available with the certification options listed. The certification does not apply to the entire assembly.