Throw-Type Back Pressure Valve Type HY
Model “HY” Throw-Type Back Pressure Valve is an internal preventer. When blowout is going to happen, the Kelly rod should be removed immediately and the back pressure valve assembly should be put into the I.D. and then pumped downward to the required place. Thus, the blowout can be prevented.
Specifications
| Product Code | O.D mm（in） | Connection | Pressure grade （Mpa） |
| NFQ105 | 105(4 1/8) | NC31 | 70、105 |
| NFQ127 | 127(5) | NC38 | 70、105 |
| NFQ159 | 159(6 1/4) | NC46 | 70、105 |
| NFQ168 | 168(6 5/8) | NC50 | 70、105 |
| NFQ178 | 178(7) | 5 1/2FH | 70、105 |
| NFQ184 | 184(7 1/4) | 5 1/2FH | 70、105 |