Slurry mixer outlet

In a wallboard manufacturing system, a mixing apparatus for mixing and dispensing a slurry onto a wallboard forming surface, comprising:

• a centrifugal mixer having a housing configured for receiving and mixing slurry components, having a discharge outlet at a tangent to said housing;
• a conduit in fluid communication with said outlet and having a spout for discharging the slurry;
• said conduit including an additive inlet portion in fluid communication with said outlet, and having at least one inlet for receiving at least one additive;
• at least one volume restrictor on said conduit for restricting the volume of the slurry dispensed from said spout;
• and
• at least one pressure reducer associated with said spout and configured for reducing the pressure of the slurry dispensed from said spout;
• said conduit being configured to maintain laminar flow of the slurry from said outlet to said spout, and being provided with a sufficient length for enhancing uniform mixing of the at least one additive and the slurry.

A method for providing an evenly mixed additive enhanced slurry to a web, comprising:

• inserting calcined gypsum and water into a mixing chamber of a mixer through one or more inlet of the mixing chamber;
• agitating the contents of the mixing chamber to form an aqueous dispersion of the calcined gypsum;
• passing the agitated contents from an outlet of the mixer into a slurry dispensing apparatus including a conduit;
• introducing an additive into the mixture in the slurry dispensing apparatus and mixing the additive with the slurry;
• creating a back-pressure on the mixture in the apparatus by reducing the volume of mixture being emitted from the conduit, said back-pressure being created by constricting the conduit;
• and
• controlling the pressure of the additive enhanced slurry dispensed from a spout of the conduit.