Key Components for your Pigging System
Pigging system affiliated components are those key components associated with the operation of the pigging system but not having special functional design needed for the pigging application.
Standard Isolation Valves
Standard isolation valves are used to isolate the pigged sections from the non-pigged sections of the non-pigged sections of the transfer line. For example, standard isolation valves would be used to isolate the adjacent supply and discharge lines from the main pigged transfer line.
Utility Line Isolation Valves
Pig movement is accomplished by controlling the flow of compressed air, nitrogen (N2), or liquid used to push the pig through the line. Utility valves are mounted on these supply lines as well as on the vent and pressure relief lines connected to the system.
Air Regulators and Drying Filters
When pig movement is controlled through the use of compressed air nitrogen (N2), a regulator is needed to control the pressure and volume. Regulated air pressure or N2 will be used to control pig travel rates in both filled and empty transfer lines. Since different pressures are needed for pushing pigs in filled lines vs. returning pigs to the pig launcher in an empty line, separate air pressure regulators are required. When pigging systems are exposed to cold environments, dry air/N2 is needed to prevent condensation and freezing of regulators and air operated components, such as valve actuators. Clean dry air/N2 is provided by the use of both desiccant (water removing) and particulate removing filters.
Gauges & Transmitters
Pressure monitoring gauges or transmitters are often desired to provide operators with a visual indication of the line pressures that exist in the system. Pressure monitoring can help assure the system is operating within the expected parameters and alert operators to existing line pressures before attempting to gain access to pigs.
Depending on system design and layout, strategically placed check valves assure that pigged products and residuals pushed from the line cannot be pushed into air & vent piping or migrate back into the system from higher elevations.
Pigging Solutions systems are the most forgiving of piping variations in the industry. For this reason, our systems do not require the use of specially fabricated piggable tubing. Our systems perform well using both standard seamless and ERW seam welded ASTM pipe and therefore provide significant savings in pipe cost.
Piggable Piping Support & Installation
Pigging Solutions pigs are the most forgiving of piping variations in the industry and can often accommodate the retrofit of non-pigged transfer lines for use as pigged transfer lines. However, true pipe alignment with little internal protrusion into the line will result in the best pig performance. Pipe connections can be flanged or welded, though threaded pipe is not recommended.
Pigging Solutions recommends that piping used in pigging applications be well supported and secured to prevent piping shift and noise during the pigging process. The use of suspension hangers for pigged piping is not recommended.
Pigging Solutions will be happy to discuss specific applications and provide application specific recommendations regarding piggable piping, support, and installation.