Membrane vapour concentrator

Abstract

Apparatus for concentrating a vapor including an optional vaporizer, a vapor flow conduit; a counter flow conduit; and an optional humidity controller; wherein at least a portion of the vapor flow conduit and counter-flow conduit define respective opposed sides of a membrane. Also, a method of producing a concentrated active from a solution including an active in a solvent and having a first active-to-solvent ratio, the method comprising the steps of: (1) vaporizing the solution to form a vapor wherein the concentration of active is at about said first ratio, (2) providing a flow of the vapor to a first side of a membrane; and (3) providing an alternate flow of a gas to a second side of the membrane whereby to increase said first active-to-solvent ratio on the first side to a second active-to-solvent ratio greater than the first active-to-solvent ratio.

1 . Apparatus for concentrating a vapour comprising:
 a vapour flow conduit;   a counter-flow conduit; and   wherein at least a portion of said vapour flow conduit and said counter-flow conduit define respective opposed sides of a membrane, wherein said apparatus operates such that said membrane can be selected from a group consisting of selective or non-selective membranes.   
     
     
         2 . Apparatus according to  claim 1  further comprising a vaporizer in communication with the vapour flow conduit. 
     
     
         3 . Apparatus according to  claim 1  or  2  further comprising humidity control means for controlling the humidity of a counter flow entering the counter-flow conduit. 
     
     
         4 . Apparatus according to any one of  claims 1  to  3  comprising:
 a plurality of alternating vapour flow conduits and corresponding counter-flow conduits; and   wherein at least a portion of said each vapour flow conduit and an adjacent counter-flow conduit define respective opposed sides of a membrane.   
     
     
         5 . Apparatus according to any one of  claims 1  to  4  wherein alternating vapour flow conduits and counter-flow conduits are in a layered configuration. 
     
     
         6 . Apparatus according to any one of  claims 1  to  4  wherein alternating vapour flow conduits are in a concentric, coaxial tubular arrangement. 
     
     
         7 . Apparatus according any one of  claims 1  to  3  for concentrating a vapour comprising:
 a vapour flow conduit;   at least two counter-flow conduits; and   wherein at least a portion of said vapour flow conduit and said counter-flow conduits define respective opposed sides of membranes, wherein said apparatus operates such that said membrane can be selected from a group consisting of selective or non-selective membranes.   
     
     
         8 . Apparatus according to any one of  claims 1 - 3  for concentrating a vapour comprising
 at least two vapour flow conduits;   an alternate flow conduit; and   wherein at least a portion of said counter-flow conduit and said vapour flow conduits define respective opposed sides of membranes, wherein said apparatus operates such that said membrane can be selected from a group consisting of selective, or non-selective membranes.   
     
     
         9 . Apparatus according to any one of the preceding claims wherein each vapour flow conduit comprises an inlet and an outlet, each counter-flow conduit comprises an inlet and an outlet, and the vapour flow and counter-flow are in the same or opposite directions. 
     
     
         10 . Apparatus according to any one of  claims 1  to  7  wherein each vapour flow conduit comprises an inlet and an outlet, and the counter-flow conduit directs a counter flow in a direction at an angle to the vapour flow direction. 
     
     
         11 . A method of producing a concentrated active from a solution comprising an active in a solvent and having a first active:solvent ratio, said method comprising the steps of:
 (1) vaporizing the solution to form a vapour wherein the concentration of active is at about said first ratio,   (2) providing a flow of the vapour to a first side of a membrane; and   (3) providing an alternate flow of a gas to a second side of the membrane whereby to increase said first active:solvent ratio on the first side to a second active:solvent ratio greater than the first active:solvent ratio, wherein said membrane is selected from a group consisting of selective or non-selective membranes.   
     
     
         12 . A method for concentrating a vapour comprising the steps of
 (1) providing a flow of a vapour consisting of an active in a solvent and having a first active:solvent ratio to a first side of a membrane; and   (2) providing an alternate flow of a gas to a second side of the membrane whereby to increase said first active:solvent ratio on the first side to a second active:solvent ratio greater than the first active:solvent ratio, wherein said membrane is selected from a group consisting of selective or non-selective membranes.   
     
     
         13 . A method according to  claim 11  or  12  wherein the active is a biocide and the concentrated vapour is used to disinfect and/or sterilize an article. 
     
     
         14 . A method according to any one of  claims 11  to  13  wherein the solvent is water. 
     
     
         15 . A method according to any one of  claims 11  to  14  wherein the active is hydrogen peroxide or a peroxy compound. 
     
     
         16 . A method according to according to any one of  claims 11  to  15  wherein the first active to solvent ratio is below 35 wt %. 
     
     
         17 . A method according to any one of  claims 11  to  16  wherein the second active:solvent ratio is above 60 wt %. 
     
     
         18 . A method according to any one of  claims 11  to  17  wherein the counter-flow of gas is provided at a rate and for a time such that the second ratio reaches an equilibrium ratio beyond which it will not increase. 
     
     
         19 . A method according to any one of  claims 11  to  18  wherein the gas is air or humidity conditioned air. 
     
     
         20 . A method according to any one of  claims 11  to  19  wherein the fabric or membrane is a woven, or non-woven fabric, or a sheet or film or a combination thereof and of a single layer or multilayer construction. 
     
     
         21 . A method according to any one of  claims 11  to  20  wherein the membrane is hydrophobic. 
     
     
         22 . A method according to any one of  claims 1  to  21  wherein the membrane is Kimguard. 
     
     
         23 . A method according to any one of  claims 11  to  22  wherein the membrane is suitable for pervaporation. 
     
     
         24 . A method according to any one of  claims 11  to  23  wherein the vapour is an aqueous peroxide vapour having an initial concentration of from 6%-35 wt % of peroxide. 
     
     
         25 . A method according to according to any one of  claims 11  to  24  wherein the membrane is selected to remove one or more vapours by a process of pervaporation. 
     
     
         26 . A method for disinfecting or sterilizing an article comprising bringing a suitable biocidal solution concentrated by a method according to any one of  claims 9  to  25  into contact with the article as a vapour. 
     
     
         27 . A method for disinfecting or sterilizing an article comprising the steps
 (1) vaporizing a solution consisting of an active in a solvent and having a first active:solvent ratio,   (2) providing a flow of the vapour to a first side of a membrane; and   (3) providing an alternate flow of a gas to a second side of the membrane whereby to increase said first active:solvent ratio on the first side to a second active:solvent ratio greater than the first activer solvent ratio, and   (4) contacting the vapour from step 2 with the article for a time sufficient to disinfect or sterilize it, wherein said membrane is selected from a group consisting of selective or non-selective membranes.   
     
     
         28 . A method according to  claim 27  when conducted at atmospheric pressure or above. 
     
     
         29 . A method according to  claim 27  when conducted at below atmospheric pressure. 
     
     
         30 . A method according to according to any one of  claims 27  to  29  wherein the counter-flow of gas is provided at a rate and for a time such that the second ratio reaches an equilibrium ratio beyond which it will not increase. 
     
     
         31 . A method for disinfecting or sterilizing an article comprising the steps of
 (1) enclosing the article inside a container having a wall of which at least a part is a membrane;   (2) providing a vapour of an active in a solvent and having a first active:solvent ratio,   (3) providing, an alternate flow of a gas to a side of the membrane external to the container whereby to increase the first active:solvent ratio to a second active:solvent ratio greater than the first active:solvent ratio, and produce a concentrated vapour; and   (4) allowing the article to remain in contact with the concentrated vapour for a time sufficient to permit sterilization, wherein said membrane is selected from a group consisting of selective or non-selective membranes.   
     
     
         32 . A method according to  claim 31  wherein the membrane is impenetrable by microorganisms and the article is sterilized and stored sterile in the container.