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A method of post treating gas separation membranes to seal porous defects that are initially produced in an ultra thin selectively gas permeable layer of the membrane involves contacting the defect-bearing section of the membrane with a suspension containing caulking particles dispersed in an aqueou

A method of post treating gas separation membranes to seal porous defects that are initially produced in an ultra thin selectively gas permeable layer of the membrane involves contacting the defect-bearing section of the membrane with a suspension containing caulking particles dispersed in an aqueous medium. The caulking particles are composed of curable polymer having functional groups that can react with each other and/or the membrane composition in absence of water. The water of suspension is removed and the polymer of the caulking particles is cured to seal the defects and render the membrane highly effective for gas separations. Low surface tension of the suspension can be enhanced by incorporating a surfactant and allows asymmetric membranes to be dried directly from water wet to dry state, for example by evaporation, without excessive densification of porous portions of the membrane.

대표청구항 ▼

A method of post treating gas separation membranes to seal porous defects that are initially produced in an ultra thin selectively gas permeable layer of the membrane involves contacting the defect-bearing section of the membrane with a suspension containing caulking particles dispersed in an aqueou

A method of post treating gas separation membranes to seal porous defects that are initially produced in an ultra thin selectively gas permeable layer of the membrane involves contacting the defect-bearing section of the membrane with a suspension containing caulking particles dispersed in an aqueous medium. The caulking particles are composed of curable polymer having functional groups that can react with each other and/or the membrane composition in absence of water. The water of suspension is removed and the polymer of the caulking particles is cured to seal the defects and render the membrane highly effective for gas separations. Low surface tension of the suspension can be enhanced by incorporating a surfactant and allows asymmetric membranes to be dried directly from water wet to dry state, for example by evaporation, without excessive densification of porous portions of the membrane. rein the guide device has a flat sided portion for engagement by a rotary tool for adjusting the position of the stop, the arrangement being such that the flat sided portion projects from the housing for access by the rotary tool only when the guide device is in the released condition.8. An apparatus as claimed in claim 2, including indicia denoting the position of the guide device and/or the direction of movement of the guide device necessary to achieve a particular flow condition in use.9. An apparatus as claimed in claim 1, wherein the guide device comprises a sleeve having a plurality of slots, each slot corresponding to a respective one of said pre-set positions and being selectively alignable with a projection fixed relative to the housing.10. An apparatus as claimed in claim 9, wherein a peripheral portion of the sleeve is extended axially beyond the rest of the sleeve to form a lug which limits the extent of rotary movement of the guide device.11. An apparatus as claimed in claim 1, wherein rotary movement of the adjuster with said guide device is permitted by the guide device only within a selected arc between said pre-set positions.