| 单词 | crown block |
| 释义 | crown block in the Oil and Gas Industry (kraʊn blɒk) Word forms: (regular plural) crown blocks noun (Extractive engineering: Field development, Drilling) A crown block is a fixed set of sheaves (= pulleys) at the top of a derrick, over which the drilling line is run. The crown block is an assembly of sheaves mounted on beams at the top of the derrick or mast. The crown block is a stationary pulley located at the top of the derrick. A crown block is a fixed set of sheaves at the top of a derrick, over which the drilling line isrun. |
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