Abstract: A polymer characterised by the presence of ylid linkages in the main polymer chain of formula (A) where the dashed line represents the remainder of a ring system for which the N+ provides a heteroatom, and E is a strongly electron withdrawing group. Preferred polymers in accordance with the invention are characterised by the presence of linkages in the polymer main chain of formula (I). The polymers of the invention may be fabricated as membranes for use in various separation processes, e.g. ultrafiltration, nanofiltration, and reverse osmosis.

Abstract: A reverse osmosis membrane having a support which itself has properties of salt rejection laminated to a layer of a cross-linked polyol. The support is a sulphonated aromatic polyether sulphone, and the polyol ma be polyvinyl alcohol.

Abstract: Apparatus for removing piping from the ground comprises a cable (1) which has pipe engaging means (2) disposed along its length. The pipe engaging means (2) are arranged such that the cable (1) is insertable into a pipe (3) in one direction but that attempted withdrawal of the cable (1) in the opposite direction relative to the pipe (3) causes the pipe engaging means (2) to jam the cable (1) in the pipe (3). The pipe (3) can then be pulled from the ground, the pulling force being distributed along the length of the pipe (3).

Abstract: A composite membrane comprises an inorganic support having interstices and porous inorganic films of sintered non-metallic particles carried by the support and bridging the interstices thereof. The support is preferably a woven metal mesh, with the films substantially coplanar with the support. The films may be formed by applying a suspension of refractory particles in a polymer solution to bridge the interstices of the support, and heating the films to partly sinter the particles. Since the films are in compression at ambient temperature, any cracks that may be formed by damage to the composite membrane tend not to propagate.

Abstract: Industrial filtration apparatus for the separation of solids entrained in a fluid stream comprises: a flexible perforate filtering sleeve closed at one end such that fluid can pass through perforations in the sleeve but entrained solids of a predetermined size are retained within the closed end of the sleeve. The apparatus has a structure for holding the sleeve about a discharge pipe for the fluid at a point between the closed and open ends of the sleeve, and for restraining movement of the sleeve away from the pipe; the apparatus is adapted such that in response to a predetermined fluid (e.g. hydraulic) pressure within the sleeve between its closed end and the discharge pipe, the closed end is allowed to be displaced away from the discharge pipe, thereby drawing a portion of the sleeve nearer its open end into a position forward of the pipe to expose said portion to the fluid stream.

Abstract: A composite membrane comprises an inorganic support having interstices and porous inorganic films of sintered non-metallic particles carried by the support and bridging the interstices thereof. The support is preferably a woven metal mesh, with the films substantially coplanar with the support. The films may be formed by applying a suspenion of refractory particles in a polymer solution to bridge the interstices of the support, and heating the films to partly sinter the particles. Since the films are in compression at ambient temperature, any cracks that may be formed by damage to the composite membrane tend not to propagate.