方钻杆旋塞也叫方钻杆考克或钻杆安全阀。钻井液可无压降地自由流过该阀。这类阀用作钻杆安全阀，或者装在方钻杆以上控制防喷。或者在方钻杆下，当方钻杆卸下时防止钻井液流失。其工作压力可达10,000psi或15,000psi。
| Name |
Type |
O.D |
I.D |
Connection |
| mm(inch) |
mm(inch) |
API |
| Upper kelly valve |
XS197A |
197;7-3/4'' |
76.2;3'' |
6-5/8REG LH |
| XS200-1 |
200;7-7/8'' |
6-5/8REG LH |
| XS203-1 |
203;8'' |
6-5/8REG LH |
| Lower kelly valve |
XS111-1 |
111;4-3/8'' |
40;1-37/64'' |
NC31 |
| XS121-2 |
121;4-3/4'' |
44.5;1-3/4'' |
NC38 |
| XS135-1 |
135;5-5/16'' |
| XS168A |
168;6-5/8'' |
71.4;2-13/16'' |
NC50 |
| XS178-3 |
178;7'' |
5-1/2FH |
| XS184A-1 |
184;7-1/4'' |
5-1/2FH |
| When ordering or requesting quotation, if size out of above specification, pls. specify clearly. |
