Method and apparatus to minimize air-slurry separation during gypsum slurry flow

An apparatus configured for connection to a mixer for receiving a gypsum slurry, said apparatus comprising:

• a conduit having a main inlet in slurry receiving communication with the mixer outlet and extending in a downstream direction to a spout for discharging the slurry, said conduit providing a flow path for a flow stream of the slurry;
• two spaced apart bends in said conduit to cause a change of direction of said flow stream between said main inlet and said spout, wherein a cross section of the flow stream does not expand in the bends;
• a linear section of said conduit extending between the two bends, wherein the cross section of the flow stream does not expand in the linear section, and
• at least one expansion section in said conduit to cause an expansion of a cross section of said flow stream between downstream one of the two bends and said spout, wherein the flow stream does not change direction in the at least one expansion section.

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

• inserting calcined gypsum and water into a mixing chamber of a mixer through at least one inlet of the mixing chamber;
• agitating the contents of the mixing chamber to form a slurry comprising an aqueous dispersion of the calcined gypsum;
• passing the slurry from an outlet of the mixer into a slurry dispensing apparatus including a conduit;
• introducing an additive into the slurry at a point along a length of the conduit in the slurry dispensing apparatus to achieve a flow stream of a slurry/additive mixture through the conduit;
• and
• changing a direction of the flow stream while not changing a cross section of the flow stream, and thereafter, directing the flow stream through a linear leg of the conduit without changing a cross section of the flow stream or a direction of the flow stream, and thereafter, expanding a cross section of the flow stream without changing a direction of the flow stream, and thereafter changing a direction of the flow stream while not changing a cross section of the flow stream, all prior to the flow steam exiting from an outlet of the conduit.

An apparatus configured for connection to a mixer for receiving a gypsum slurry, said apparatus comprising:

• a conduit having a main inlet in slurry receiving communication with the mixer outlet and extending in a downstream direction to a spout for discharging the slurry, said conduit providing a flow path for a flow stream of the slurry;
• a first bend in said conduit to cause a change of direction of said flow stream between said main inlet and said spout, wherein a cross section of the flow stream does not expand in the bend;
• a linear segment in said conduit between said first bend and said spout, wherein a cross section of the flow stream does not expand in the linear segment;
• at least one expansion section in said conduit to cause an expansion of a cross section of said flow stream between said linear segment and said spout, wherein the flow stream does not change direction in the at least one expansion section;
• and
• a second bend in said conduit to cause a change of direction of said flow stream between said expansion section and said spout, wherein a cross section of the flow stream does not expand in the bend.