Abstract: A method for installing a lightweight optical fiber unit, preferably less than approximately 10 g/m, into a tube, by pulling the optical fiber unit through the tube using a pulling member. The pulling member may be attached to the optical fiber unit by a braided sheath. Alternatively, the pulling member itself may be a braided tube.

Abstract: An optical fiber assembly is described exhibiting antistatic behavior comprising at least one optical fibre and having an external organic polymer-based coating which contains a non-aqueous, or substantially non-aqueous, antistatic composition comprising (a) an antistatic agent(s), and (b) an organic liquid(s) having a dielectric constant of .gtoreq.15 and a boiling point of .gtoreq.100.degree. C.

Abstract: A termination system is provided for use with optical fibre members installed in tubular passageways using a flow of air or other gas. The system comprises a chamber defined by a body having an opening provided with a removable cover. An end of at least one passageway in which a first optical fibre member may be installed is terminated on the body so that the passageway communicates with the interior of the chamber. Means are mounted on the cover for terminating an end of at least one second optical fibre member. Preferably the passageway carries a plurality of first optical fibre members and the cover has means for terminating the ends of an equal plurality of the second optical fibre members.

Abstract: A duct is provided for receiving an optical fibre member by blowing. The duct is formed at least in part of a plastics material which is electrically conductive or has electrically conductive material such as carbon black held therein or has an electrically conductive material applied thereto preferably the duct has a radially inner layer defining an inside wall of the duct and at least one further layer positioned outwardly of the inner layer, the inner layer being formed of the plastics material which is electrically conductive or has electrically conductive material held therein or had an electrically conductive material applied thereto.

Abstract: A method is described for introducing one or more optical fibre members (1) into a tubular passageway (2). The method involves passing a current of fluid, preferably air, into and through a venturi (6) the downstream side of which communicates with the passageway (2). The optical fibre member (1) is introduced into the venturi (6) via a hypodermic tube (7) and then into the passageway (2). Apparatus for carrying out the method are described.

Abstract: An optical fibre cable comprises an inner sheath containing at least one optical fibre member, and an outer sheath containing the inner sheath. The inner sheath is of a material which is soft and has a low modulus of elasticity. The outer sheath of a material having bulk properties, such as density and stiffness, and surface properties, such as surface texture and friction such that the cable can be propelled along a duct by a flow of air travelling along the duct. An intermediate sheath may be provided between the inner and outer sheaths.

Abstract: An optical fibre cable comprises a plurality of optical fibre structures each of which comprises an optical fibre surrounded by at least one sheath layer. The optical fibre structures are separably held together side-by-side. The optical fibre cable is propellable along a tubular pathway by fluid drag of a gaseous medium passing over the cable, and each of the individual optical fibre structures is preferably also so propellable when the said structures are separated from one another.

Abstract: A coupling between first and second tubular members comprising a flexible retaining ring fitted over the first tubular member below an annular enlargement thereof and entering into screw-threaded engagement with internal screw-threading on the second tubular member or a connector element attached thereto. The retaining ring is a split-ring member whose longitudinally extending slit enables it to be passed lengthwise over the first tubular member and is so dimensioned that on re-assuming its original form, the opposed margins of the slit abut and the retaining ring is held against the first tubular member against removal therefrom by the enlargement, and the second tubular member or connecting member is coupled to the first tubular member. A sealing member is positioned at the coupling to form a fluid-tight seal at the junction of the tubular members.

Abstract: A safety locking arrangement is provided on a valve for control of fluid flow comprising a valve body having a seat with a flow passage passing therethrough and a valve closure member located within the body. The valve closure member is adapted to engage the seat to effect closure of the valve. The valve closure member is carried by a cap adapted to enter into screw-threaded engagement with the valve body at the mouth thereof. To ensure retention of the cap on the body, the cap additionally enters into screw-threaded engagement with an annular retaining means disposed around and formed separately from the valve body, with the valve body itself being so formed in the mouth region that the retaining means cannot be withdrawn therefrom merely by rotation and/or displacement lengthwise of the valve body.

Abstract: A process for storing materials under predetermined positive or negative pressure comprising inserting and sealing a fragile storage container within a gas-tight outer container capable of withstanding a pressure differential on opposite sides of its walls respectively greater or less than the said predetermined positive or negative pressure, and substantially filling the interspace between the two containers with a liquid, the fragile container incorporating pressure equalizing means whereby the pressure on opposite sides of the fragile container wall is equalized during the creation of said predetermined positive or negative pressure within the fragile container.