Abstract: A retaining device for fluid treatment apparatus having a stack of membranes and spacers in which the stack is clamped between two end plates which are provided with a projection or opening and two side plates which are provided with an opening or projection co-operating therewith, movement of the sideplates relative to the end plates, parallel to the end plates, effecting movement together of the end plates due to inclined surfaces on the projections and/or openings.

Abstract: A stack of membranes and spacers is held between upper and lower plates, the lower plate having hinged thereto, at least two side plates. These may be hinged by being formed integrally so as to be flexible outwardly, or may be hinged by suitable co-operating projections and cut-outs or by more conventional hinge-means. The upper plate is locked by co-operating projections and cut-outs on the upper plate and the top edges of the side plates. Means may be provided to enable the upper plate to be pressed downwardly to different positions to compress the stack to different degrees, these means, for example, including rack shaped surfaces on the projections and/or cut-outs.

Abstract: Membrane support-plates for fluid separating apparatus, and apparatus using such support-plates, wherein the support-plates are generally rectangular, being formed of two stamped metal plate elements arranged back-to-back, each element having a cell in its face over which extends a membrane, an elongate orifice adjacent one or both ends thereof for the introduction of fluid to be treated, a transverse cavity extending adjacent each transverse edge of a cell and a detachable bar and/or gasket located in each cavity to hold the gasket in a leakproof manner over its entire width.

Abstract: Membrane support-plates for fluid separating apparatus, and apparatus using such support-plates, wherein the support-plates are generally rectangular, being formed of two stamped metal plate elements arranged back-to-back, each element having a cell in its face over which extends a membrane, an elongate orifice adjacent one or both ends thereof for the introduction of fluid to be treated, and a detachable device located in each face having a membrane, to hold the membrane over the entire periphery of the cavity.