A flaskless molding machine includes: an upper flask; a lower flask; an upper sand tank; an upper plate attached to a lower end of the upper sand tank; a first lower sand tank; a second lower sand tank storing mold sand supplied from the first lower sand tank; a lower plate attached to an upper end of the second lower sand tank, with at least one supply port being formed, the supply port allowing the second lower sand tank to communicate with an inside of the lower flask; at least one pressure detector detecting a pressure of at least one tank among the upper sand tank, the first lower sand tank and the second lower sand tank; and a control unit connected to the pressure detector and obtaining a detection result of the at least one pressure detector.

A flaskless molding machine includes: an upper flask; a lower flask; an upper sand tank; an upper plate attached to a lower end of the upper sand tank; a first lower sand tank; a second lower sand tank storing mold sand supplied from the first lower sand tank; a lower plate attached to an upper end of the second lower sand tank, with at least one supply port being formed, the supply port allowing the second lower sand tank to communicate with an inside of the lower flask; at least one pressure detector detecting a pressure of at least one tank among the upper sand tank, the first lower sand tank and the second lower sand tank; and a control unit connected to the pressure detector and obtaining a detection result of the at least one pressure detector.

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.