Double pipe drilling strand valve has outer sleeve and inner sleeve, where outer sleeve is connected at two axial ends with outer pipe of double pipe drilling strand

摘要

The double pipe drilling strand valve has an outer sleeve (1) and an inner sleeve (2), where the outer sleeve is connected at two axial ends (1a,1b) with an outer pipe of a double pipe drilling strand. The inner sleeve is connected at two other axial ends (2a,2b) with an inner pipe of the double pipe drilling strand, where sealing surfaces (1c,2c) are made of metal.