Abstract: An apparatus for producing shredded aggregate from, e.g., boards of expanded polystyrene, is described. The apparatus includes a shredding box defining a shredding chamber; a rotor housed in the shredding box; means for driving the rotor; a plurality of saw blades coupled to the rotor in linear succession, each saw blade having a plurality of spaced apart teeth, each successive saw blade being coupled to the rotor such that its teeth lie about halfway between the teeth of an adjacent saw blade; receiving means in the shredder box for receiving material to be shredded; and take-away means coupled to the shredder box for removing shredded material from the shredding chamber. Low density (e.g., 0.4-0.5 pcf loose bulk density) material having a uniform particle size distribution over time can be economically produced.

Abstract: A slurry distributor (S) for distributing a low viscosity fluid into a viscous, hydraulic slurry comprises a main conduit (1) located on a first axis .alpha. for conducting a flowing, viscous, hydraulic slurry towards an orifice (3). The distributor (S) has an air injector (5) defined by a stem (7) located on a second axis .beta.. The air injector (5) is for introducing air into the slurry to disperse it from the orifice (3). A second injector (9) located on a third axis .gamma. and intersecting the main conduit (1) is used to introduce a low viscosity liquid, preferably an accelerator, into the flowing slurry such that the low viscosity liquid impinges on the air injector stem (7) before dispersion. The distributor is especially useful with fireproofing compositions since it provides effective distribution of a viscous, hydraulic, cementitious slurry with an acidic accelerator.