Definition - What does Casing Adapter mean?
A casing adapter is a circular mechanism used when the casing is a smaller, or in rare cases larger, diameter than the diameter of the casing pusher. The casing adapter is designed to provide lateral as well as axial support to the steel casing that is being driven into place.
Trenchlesspedia explains Casing Adapter
Casing adapters are used in line with the master casing pusher and may be threaded, flanged, studded, or slip-on welded when installed on the casing pipe. When there is a difference in the circumference, a series of casing adapters may be used.
Like the casing, the casing adapter is also made of steel in order to withstand the force of pipe jacking and the like, and to resist the internal and external forces on the casing.