Stop collars run on casing strings to maintain centralizer placement during running and cementing operations, keep centralizers and other casing attachments in place on the casing.
Stop collars use set screws for increased holding force. The hinged design is for applications on upset tubing. These stop collars are available in slip-on for tight clearances and hinged for semi-tight clearances. The size is from 2-3/8''- to 30''
Hinged stop collars that use hardened inserts (dogs) to provide a positive lock onto the casing. The specially designed dogs bite into the casing, which provides the stop collar's strong holding force. The recommended torque on the bolt is approximately 25 to 35ft-lb. When properly installed, the hinged stop collar can provide a holding force up to 40,000lb.
Slip-on stop collar with set screws is slipped onto the end of casing and up to the top of the joint to the desired location. The set screws are tightened to approximately 35ft-lbf. This style of stop collar can hold forces up to 20,000lb. They are designed for close-tolerance liner jobs as well as in the installation of cement baskets and cetralizers of different designs. This style stop collar is available in 3 1/2-in. to 30-in. casing sizes.
The installation for stop collars:
1.When using mobile screw type stop collar, slip over the casing, tighten the screws using wrench.
2.When using fixed screw stop collar, put the collar around the casing, insert the screw, and knock into screws by hammer.
3. When installing buckle type stop collar, buckle the stop collar onto the casing, lock with pin, knock into the screws.
Contact Person: Mrs. Liza