A method of reusing core sand includes: crushing a core used for casting into granules; heating the granules at a temperature of 300 C. to 550 C.; causing the heated granules to collide against each other such that water glass used as a binder detaches from the core sand; and blowing air into a mixture of the water glass and the core sand, which are detached from each other, such that the core sand is separated and collected from the mixture due to a difference in specific gravity between the water glass and the core sand.

A method of reusing core sand includes: crushing a core used for casting into granules; heating the granules at a temperature of 300 C. to 550 C.; causing the heated granules to collide against each other such that water glass used as a binder detaches from the core sand; and blowing air into a mixture of the water glass and the core sand, which are detached from each other, such that the core sand is separated and collected from the mixture due to a difference in specific gravity between the water glass and the core sand.

A mixing and adjusting method for foundry sand includes calculating a total supplied water amount until a compactability (CB) value of mixed sand becomes larger than a lower limit value of a target CB value range, determining the total supplied water amount as a predetermined amount of water associated with an electric resistance of the foundry sand, and determining a ratio of a variation in the CB value corresponding to an additionally supplied water amount from the additionally supplied water amount during an additional water pouring and the CB value of the mixed sand.

Teaching storage means stores teaching data created on the basis of signals from a first pulse generator, a first shaft detector, a second pulse generator, and a second shaft detector, in a storage unit as a sequence control program of molding operation of a self-hardening mold when teaching operation of throwing kneaded self-hardening foundry sand from a discharge port into a molding flask is performed by manually moving a conveyor arm and a kneading arm. Molding playback means reads out the sequence control program from the storage unit to control and drive a first pivot motor and a second pivot motor on the basis of the sequence control program to pivot the conveyor arm and the kneading arm, and then throws the self-hardening foundry sand from the discharge port of the kneading arm into the molding flask to reproduce the molding operation.

Provided is a method of producing foamed sand (s) for forming a sand mold. The foamed sand (s) includes sand particles (p) and foam (f) adhering to surfaces of the sand particles (p). The foam (f) contains water glass (b), water (w), and a surfactant (c). According to the method, an aqueous surfactant solution (e) in which the surfactant (c) is dissolved is frothed to generate froth (d) from the aqueous surfactant solution (e). Then, the generated froth (d), the water glass (b), and the water (w) are kneaded with the sand constituted by the sand particles (p).

Provided is a method of producing foamed sand (s) for forming a sand mold. The foamed sand (s) includes sand particles (p) and foam (f) adhering to surfaces of the sand particles (p). The foam (f) contains water glass (b), water (w), and a surfactant (c). According to the method, an aqueous surfactant solution (e) in which the surfactant (c) is dissolved is frothed to generate froth (d) from the aqueous surfactant solution (e). Then, the generated froth (d), the water glass (b), and the water (w) are kneaded with the sand constituted by the sand particles (p).

The present invention concerns a casting sand cooler comprising a sand chamber having an air inlet optionally with a fan for the feed of air into the sand chamber and an air outlet optionally with a fan for sucking air out of the sand chamber. To provide an improved casting sand cooler in which the sand discharge during the cooling operation by way of the air outlet is markedly reduced, it is proposed according to the invention that a dynamic wind sifter which is rotatable about an axis and which is so arranged that substantially the complete air flow leaving the sand chamber through the air outlet is passed through the dynamic wind sifter.

A mold-making device may include a stirring device including a stirring tank and at least one stirring blade. The stirring device may further include a packing port that is configured to open and close on a bottom of the stirring tank. The stirring device may stir a particulate aggregate and at least one additive by rotating the at least one stirring blade within the stirring tank to yield an admixture. A forming mold may communicate with the packing port and mold the admixture into a predetermined shape. A packing device may compress a surface of the admixture within the stirring tank and pack the admixture into the forming mold via the packing port.

A continuous mixing apparatus for a powder/granular material and a viscous liquid, with a mixing cylinder, a shaft member which is on a central axis of the mixing cylinder and rotates inside the mixing cylinder, and a plurality of mixing paddles disposed on a surface of the shaft member, wherein the mixing cylinder is with a powder/granular material feed port on one end portion, a mixed material discharge port on the other end portion, and a viscous liquid injection unit between the powder/granular material feed port and the mixed material discharge port, and the plurality of mixing paddles are disposed on the shaft member so as to form a spiral around the central axis, the plurality of mixing paddles being, in at least a portion between the viscous liquid injection unit and the mixed material discharge port, attached to provide first rows having an attachment angle of 5 to 60.

A continuous mixing apparatus for a powder/granular material and a viscous liquid, with a mixing cylinder, a shaft member which is on a central axis of the mixing cylinder and rotates inside the mixing cylinder, and a plurality of mixing paddles disposed on a surface of the shaft member, wherein the mixing cylinder is with a powder/granular material feed port on one end portion, a mixed material discharge port on the other end portion, and a viscous liquid injection unit between the powder/granular material feed port and the mixed material discharge port, and the plurality of mixing paddles are disposed on the shaft member so as to form a spiral around the central axis, the plurality of mixing paddles being, in at least a portion between the viscous liquid injection unit and the mixed material discharge port, attached to provide first rows having an attachment angle of 5 to 60.