1. Inner-closing design 2.The upper & Lower sub inner diameter is same as that of casing 3.Continous cementing allowed

Stage Cementer

With inner-closing design,the SJG-A stage cementer can realize permanent self-locking after closing.The pressure-relief design prevents fluid trapping and compression between the opening device and the closing plug during the closing phase of the tool’s operation.The I.D. of upper/lower sub is the same as that of casing,but smaller than that of closing sleeve,which can minimize chances of damages to closing sleeve.The inner seats are made of an easily drilled butyronitrile rubber/aluminum material.Both the opening and closing seats lock against rotation for easy drillout.It is used in the operation of continuous cementing with pumping-down opening plug.

* Parameters

Specifications mm	Φ177.8
O.D.  Max. (mm)	208
Drill-out I.D.(mm)	155
Overall length (mm)	1182
Rated load,t	170
Sealing Capacity (Mpa)	25
Opening pressure (Mpa)	7
Opening Force (kN)	136
Closing pressure (Mpa)	5
Closing Force (kN)	95
Lower Sliding Sleeve I.D. (mm)	115
Upper Sliding Sleeve I.D. (mm)	125

Two-Stage Cementing Collar