An object of the invention is to prevent differences in the flow rate and the specific gravity of a gypsum slurry from being caused between slurry discharge ports, to divide a current of the slurry into streams without a factor of stagnation of the slurry provided at a branch part, and also, to ensure a sufficient distance between the discharge ports. The slurry delivery conduit (10) has a rectilinear tube segment (14), a branch part (15) and branch tube segments (16). A tube-wall joint portion (20) of the branch tube segments configures a counter-flow splitting element (22) in a form of V-letter at the branch part. The slurry is introduced from a mixing area (51) into the rectilinear tube segment, which configures a straight rectilinear fluid passage. The rectilinear tube segment rectifies a flow of the slurry to be an axial or rectilinear current (S), and the axial or rectilinear current is split into branch streams (S1, S2) by the counter-flow splitting element.

A pretreatment mixing and stirring device, arranged at a stage prior to a slurry formation mixing and stirring device which forms a gypsum slurry by kneading a calcined gypsum and water, and performing a pretreatment by mixing a calcined gypsum with one or more kinds of additives selected from liquids and powders, comprising: a cylindrical housing having a top plate, a bottom plate arranged to oppose to the top plate, a side plate arranged between the top plate and the bottom plate, and a mixing and stirring region where the calcined gypsum and the additive are mixed and stirred in an interior surrounded by the top plate, the bottom plate, and the side plate; a disk-shaped rotating plate arranged inside the housing; a rotating drive shaft, penetrating the top plate or the bottom plate of the housing, and coupled to the rotating plate; a calcined gypsum supply port, arranged in the top plate, and configured to supply the calcined gypsum to the mixing and stirring region; and an additive supply port, arranged in one of or both of the top plate and the side plate, and configured to supply the additive to the mixing and stirring region, is provided.

An apparatus for inserting and removing a mixer rotor pin includes at least one rotor pin with a transverse bore, as well as a rod dimensioned for slidably engaging the transverse bore. The apparatus also includes a mixer rotor pin insertion and removal tool having a tool body. A bottom of the tool has a slot for selectively engaging the aforementioned rod upon insertion of the rod into the transverse bore, and a top of the tool has a non-circular socket for accommodating a driver tool.

An agitator for a gypsum wallboard mixer is provided and includes a circular disc with an upper surface, a drive shaft extending vertically from the upper surface, a lump ring secured to the upper surface, the lump ring being provided in a plurality of spaced, adjacent arcuate segments.

A gypsum slurry mixer output canister is provided, including a canister housing having an upper end, an opposite lower end and defining a canister interior, a cover secured to the upper end, a slurry inlet in operational relationship to the upper end, a spiral block associated with the upper end, and having a helical flow surface depending into the interior. A flow distributor is secured to the lower end and is in fluid communication with the interior, and a slurry outlet is defined by the lower canister housing end.

An apparatus for inserting and removing a mixer rotor pin includes at least one rotor pin with a transverse bore, as well as a rod dimensioned for slidably engaging the transverse bore. The apparatus also includes a mixer rotor pin insertion and removal tool having a tool body. A bottom of the tool has a slot for selectively engaging the aforementioned rod upon insertion of the rod into the transverse bore, and a top of the tool has a non-circular socket for accommodating a driver tool.

A gypsum slurry mixer output canister is provided, including a canister housing having an upper end, an opposite lower end and defining a canister interior, a cover secured to the upper end, a slurry inlet in operational relationship to the upper end, a spiral block associated with the upper end, and having a helical flow surface depending into the interior. A flow distributor is secured to the lower end and is in fluid communication with the interior, and a slurry outlet is defined by the lower canister housing end.

An object of the invention is to prevent differences in the flow rate and the specific gravity of a gypsum slurry from being caused between slurry discharge ports, to divide a current of the slurry into streams without a factor of stagnation of the slurry provided at a branch part, and also, to ensure a sufficient distance between the discharge ports.

The slurry delivery conduit (10) has a rectilinear tube segment (14), a branch part (15) and branch tube segments (16). A tube-wall joint portion (20) of the branch tube segments configures a counter-flow splitting element (22) in a form of V-letter at the branch part. The slurry is introduced from a mixing area (51) into the rectilinear tube segment, which configures a straight rectilinear fluid passage. The rectilinear tube segment rectifies a flow of the slurry to be an axial or rectilinear current (S), and the axial or rectilinear current is split into branch streams (S1, S2) by the counter-flow splitting element.

A mixing apparatus for producing aqueous calcined gypsum slurry includes a housing, a rotor assembly, and an actuator system. The housing defines a mixing chamber therewithin. A top lid of the housing includes a lid ring extending along a normal axis toward a bottom thereof. The rotor assembly includes a rotor disposed within the mixing chamber and a drive shaft extending along and rotatable about the normal axis. The rotor is rotatively coupled with the drive shaft and extends radially therefrom. The upper surface of the rotor and the lid ring are separated by a lid ring gap along the normal axis. The actuator system is arranged with the rotor assembly to selectively move the rotor over a range of travel along the normal axis between a lowered position and a raised position to selectively change the lid ring gap.

Behavior of a flow of foam ejected to a gypsum slurry can be stabilized, and a relatively large amount of foam can be homogeneously or uniformly dispersed in the slurry. A mixer has a mixing area for preparing gypsum slurry, a slurry delivery section for delivering the slurry from the mixing area, and a feeding port for feeding foam to the slurry in the mixing area and/or the slurry delivery section under pressure. The slurry having the foam mixed therein is supplied to a production line for forming gypsum boards or gypsum-based boards. The feeding port is provided with a partition member dividing an ejecting region. The ejecting region is divided into a plurality of openings, which simultaneously eject the foam to the slurry.