Sweco Fab., Inc. designed and fabricated pig launchers and receivers with closure for a crude export pipeline in Mexico. These units were custom designed per ASME CODE B31.3 and weigh 2,400 lb. They are 120″ in length and have 12″ dia. minor barrels and 18″ dia. major barrels. The barrels are fabricated from API 5L Gr. B pipe, the flanges from SA105 and the closures from carbon steel. The launchers are designed for operating temperatures that vary from -20°F to 212°F at 943 psig. They were radiography tested and hydro-tested at 1,415 psig for two hours.
The pig launchers and receivers were designed for a coal-bed methane gas production facility in Colorado. They are equipped with an integral safety locking system which works on the principle of mechanical key interlocking (transfer of keys). This system avoids serious injuries from human error and insures safety of personnel.
One starter key per launcher/receiver is kept in a box located in the control room. Each lock is executed with two keys. When the first valve is opened with this starter key, it releases the second key. This key is transferred to next valve which releases second key from that valve and so on and so forth. This process guides the operator through the specified sequence for opening and closing valves with unique a key for each step.