Patent ID: 9458682
Filing Date: 2016-10-04
CPC Classification: E21B

Claim Text:
1. A coiled tubing injector, comprising: a plurality of chains, each of which is comprised of a continuous loop and carries a plurality of grippers, the plurality of chains being arranged for gripping tubing placed between the plurality of chains; the plurality of chains comprising at least two driven chains; and a drive system for turning the plurality of chains comprising at least two drive motors, each of the at least two drive motors being coupled, respectively, to one of the at least two driven chains, the drive system further comprising a controller for directing flow of power to each of the least two drive motors in order to permit different rotational speeds of the least two driven chains that is less than a difference indicating that one of the at least two driven chains is slipping, and to reduce the difference in rotational speeds when the difference in rotational speeds indicates that one of the at least two driven chains is slipping.