Hot hole vibration dampener

Abstract From the Canadian patent

The specification describes a shock absorber for deep hole drill pipe which can be installed in the pipe coaxially as an intermediate part. The shock absorber comprises an outer pipe part and an inner pipe part which are movable coaxially relative to one another and are secured against twisting by torque transfer means. Located between the outer pipe part and the inner pipe part are a plurality of ringshaped spring elements stacked on top of one another. Hydraulic fluid is also sealed within the annular chamber. The spring elements are divided into at least two parallel acting spring columns which are housed in spring chambers so as to communicate with one another.