509 results about "Closed tube" patented technology

The invention relates to a hole bottom freezing cord coring drill and a coring method thereof. In the invention, liquid nitrogen is taken as a refrigerant; the liquid nitrogen absorbs heat in the gasification process so as to freeze a core at a hole bottom and inhibit a natural gas hydrate from being decomposed. The drill comprises an outer tube assembly and an inner tube assembly; and in the process of acquiring the core, a sand hitch is utilized to drag the inner tube assembly out from the outer tube assembly, an end cover and a clamp spring are dismounted, a semi-closed tube and a core sample are pumped out together from a core tube, the two ends of the semi-closed tube are sealed by rubber plugs, and the core sample and the semi-closed tube are stored in a liquid nitrogen hold-up vessel or a high-pressure container together. The invention has the advantages that rapid freezing can be realized, and the freezing effect is good; since cord coring and hole bottom freezing are combined, rapid coring without lifting the drill is achieved; in the drilling process, the inner tube assembly does not rotate, thus damages on a hydras core caused by mechanical force generated by rotation of the drill is avoided to a greater degree, the percentage of coring, the core integrity degree and the representativeness are more effectively improved; and semi-closed tube type rapid ground surfacesampling is adopted, thus the core can be rapidly obtained from the ground surface.