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верхний клапан ведущей трубы (a valve installed above the kelly that can be closed manually to protect the rotary hose from high pressure that may exist in the drill stem. paderin) | |||
верхний шаровой клапан ведущей штанги (imemine) |
upper kelly cock: 2 phrases in 2 subjects |
Sakhalin | 1 |
Sakhalin R | 1 |