By-pass valve of drill tool is used to cycle drilling fluid or killing well when the water hole of the drill bit has plugged. By-pass valve of drill tool is joined to drill bit or nearby, before drilling gas-oil layer.
Technical parameters and specifications
| Type |
O.D.(mm) |
Bearing Back Pressure |
Thread |
Drill Collar(in) |
| ZFF127 |
 127 |
35 Mpa, 70 Mpa |
NC38 |
5" |
| ZFF159 |
159 |
35 Mpa, 70 Mpa |
NC46 |
6 1/4" |
| ZFF165 |
165 |
35 Mpa, 70 Mpa |
NC50 |
6 1/2" |
| ZFF178 |
178 |
35 Mpa, 70 Mpa |
NC50 |
7" |
| ZFF203 |
203 |
35 Mpa, 70 Mpa |
6 5/8REG |
8" |
| ZFF228.6 |
228.6 |
35 Mpa, 70 Mpa |
7 5/8REG |
9" |
| ZFF241 |
241 |
35 Mpa, 70 Mpa |
7 5/8REG |
9 1/2" | |
