Circulating Sub

Crossover Circulating Sub/Swages are manufactured from AISI 4140/4145. They typically are female hammer union on the top end and an IF Pin on the bottom end, but can be manufactured with any size and style connection.

The circulating sub is connected between wellhead pipe string and ground circulating system. When casing is running or finished running, the circulating sub is connected to make fluid circulation. According to the application, the circulating sub is connected between Kelly and casing or between casing and hose. The former is used for fluid circulation during connecting of casing. The later generally is used after connecting of casing.