(E21C7)

E   Fixed constructions(159733)
E21C     ining or quarrying(17294)
E21C7                 (12)
E21C7/02 - (2)

Device for drilling wells // 2005880
The invention relates to the mining industry and can be used in devices for drilling, clearing of debris mainly air-to-water mixture and dust suppression in the annulus
 
2550982.
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