Stop collars also called stop rings are widely used in casing cementing progress, they are used for preventing the casing centralizers from moving up and down when running the casings in cased hole. There are several types of stop collars, slip on stop collar with set screws, slip on stop collar with bolts, hinged latch type stop collar with bolt, hinged stop collar with spiral nails.
Slip on stop collar with set screws
Slip on stop collar with set screws (set screw stop ring) is made of a single piece collar with one or two rows of set screws to induce the gripping force. It is designed for use where higher holding forces are required. It has reliable holding force, and it is more robust than the latch-on type.
Hinged stop collar with bolt
Hinged (latch type) stop collar with bolt is used in most type of well designs. It can be used with most hinged bow centralizers. It allows quick and easy installation over casing.
Hinged stop collar with spiral nails
Hinged stop collar with spiral nails (pins) uses two spiral-locking pins that are driven to lock the collar into position around the casing. It can be latched onto the casing pipe without having to be slipped on at the end of the casing. This ensures rapid and easy installation.
Usually, one bow centralizer are installed with two stop collars, one is on the top and the other is on the bottom. Also the stop ring can be put only one in the middle of the bow spring centralizer, by this way, it will save one stop collar.
If solid body centralizers need to be fix on the casings, it’s possible to set two rows of secrews on the vanes of the solid body centralizer, so that the stop collars can be removed.
Diffrent downhole situations need different types of stop rings. They have different clampling force. After testing our stop collars, the stop rings clamping force is very big and meet very tugh conditons.
