The Kelly cock valve, which is a manually operated ball valve run in the I.D.of drill string, is one of effective tool for preventation from blowout. The kelly cock is divided into upper kelly cock valve and lower kelly cock. The upper kelly cock is connected between lower end of swivel and upper end of kelly. The lower kelly cock is connected between upper end of drill pipe and lower end of kelly or connected between lower end of kelly saver subs. The Kelly cock features a simple operation, the Kelly valve can be opened on or closed off by only turning the special operating spanner at 90° according to indicating direction. During drilling operation, the Kelly cock shall be connected at upper end and lower end of Kelly.

Type	O.D. (mm)	Water Hole Diameter    (mm)	(LH) Connection	Working Pressure (Mpa)	Suitable Range
CS146	146	50	4 1/2″REG-LH	35   70   105	Tetragonal and Hexagonal kelly
CS200	200	76	6 5/8″REG-LH	35   70   105

Type	O.D. (mm)	Water Hole Diameter (mm)	Connection	Working Pressure (Mpa)	Suitable Range
XS105	105	41	NC31	35  70   105	Tetragonal and Hexagonal   Kelly
XS121	121	50	NC38	35  70   105
XS127	127	50	NC38	35  70   105
XS165	165	61	NC46	35  70   105
XS178	178	71	NC50  5-1/2FH	35  70   105