Apparatus and Method for the Production of Foam

Abstract

An apparatus for preparing foam for incorporation into cementitious slurry comprises a conduit having an inlet for receiving a gas feed and a surfactant feed, and an outlet for allowing the exit of foam. The conduit houses a porous plug that provides a partial barrier to fluid flow along the conduit, the plug comprising a plurality of particles that are packed in a regular array and that define a three-dimensional network of pores extending therebetween. The apparatus comprises a resilient component located between the plug and the conduit.

What is claimed is: 
     
         1 . A method of preparing a gypsum product, comprising the steps of providing a gypsum stucco slurry, and incorporating a foam into the slurry,
 wherein the bubble size dispersity index of the foam is below 1.4, and the mean bubble size of the foam is at least 100 μm.   
     
     
         2 . The method as described in  claim 1  wherein the foam is incorporated into a hydraulic binder slurry. 
     
     
         3 . The method as described in  claim 1  wherein the foam includes a stabilising additive. 
     
     
         4 . The method as described in  claim 1  wherein the foam is produced by mixing a gas from a first feed and a surfactant from a second feed. 
     
     
         5 . A cementitious product, wherein the dispersity of the pores is below 1.4, and the mean pore size is at least 300 μm. 
     
     
         6 . The cementitious product as described in  claim 5  wherein the product is formed by incorporating a foam into a slurry. 
     
     
         7 . The cementitious product as described in  claim 6  wherein the foam is produced by mixing a gas from a first feed and a surfactant from a second feed. 
     
     
         8 . The cementitious product as described in  claim 6  wherein the foam includes a stabilising additive. 
     
     
         9 . The cementitious product as described in  claim 6  wherein the foam has a bubble size dispersity index of below 1.4. 
     
     
         10 . The cementitious product as described in  claim 6  wherein the foam has a mean bubble size of at least 100 μm. 
     
     
         11 . The cementitious product is a gypsum plasterboard.