Abstract: A production string with flexible electrical and/or hydraulic cables extending along therewith is lowered into a well through a blow-out preventer on the seabed and is formed by screwing together pipe lengths. The blow-out preventer having an enveloping pipe ram with an elastic valve element which, when pressurized, expands to envelope the production string at a preselected point. A core pipe is spliced into the production string at a preselected depth by way of threaded connections at its ends. A protective sleeve for the cables is attached to and around the core pipe, forming an annular space through which link pipes extend between end elements. The outlet ends of the link pipes have pressure couplings or blind plugs in unused holes. Support rings prevent the collapse of the protective sleeve under pressure.

Abstract: A switch device (1) which sequentially conducts one hydraulic fluid stream (2) to two or more independently operated hydraulic units, where the switch device (1) with one or more channel throughputs (11, 12, 13 and 14) travels helically in a holding cylinder and transfers pressure streams in rotational sequence via fixed channels (8 and 8′) in the holding cylinder to separately operated hydraulic devices. With activation and deactivation in succession with alternate pressure and pressure relief combined with corresponding spring device (4), the switch device (1) in the surrounding cylinder is simultaneously forced to perform a one-way helical and axial forward and backward movement, resulting in altered fluid communication. Full switch rotation is achieved with, for example, six equiangular waves, each at 60°, or with six different angular waves, such as 90°+60°+45°+60°+60°+45°.