The present invention includes: a connector unit configured to disconnectably connect an injection container unit and a lid member; and a vertically driving mechanism configured to cause the injection container unit and the lid member to move up and down together when the injection container unit and the lid member are connected together and to cause the lid member to move up and down when the injection container unit and the lid member are not connected together.

The present invention includes: an injection container unit; a lid member; and an ejection air supply section configured to press a foamed mixed material in the injection container unit with compressed air and thereby eject the foamed mixed material through an ejection port, the lid member being provided with a sealing body configured to deform when a fluid is injected and thereby make close contact with the inner circumferential surface of the injection container unit during the pressing.

The present invention includes: a connector unit configured to disconnectably connect an injection container unit and a lid member; and a vertically driving mechanism configured to cause the injection container unit and the lid member to move up and down together when the injection container unit and the lid member are connected together and to cause the lid member to move up and down when the injection container unit and the lid member are not connected together.

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).

A valve device (10) having a check valve mechanism (20) having a valve rod (21) and a closing element (22) disposed on one end of the valve rod (21) and intended for the compressed-air supply to a consumer (11), the valve device (10) further having an actuation mechanism (30) having a hydraulic cylinder (31), the piston (32) of the hydraulic cylinder (31) being firmly connected to the valve rod (21) and being hydraulically driven within the cylinder casing (33) of the hydraulic cylinder (31) in order to actuate the check valve mechanism (20). A control mechanism (40) for controlling the piston movement and a measuring mechanism (50) for detecting the piston position is comprised, a proportional-valve mechanism (60), which is controllable by the control mechanism (40) as a function of the piston position, being connected to the hydraulic cylinder (31) in a fluid-conducting manner. A molding machine and method for controlling a valve device are also disclosed.