Abstract: A gas venting device for molding operations is disclosed having a valve for closing off a gas evacuation system from a mold when the mold cavity is filled with melt. A positive drive mechanism is provided for closing the valve, and a mechanism is provided for allowing the valve body to close more rapidly by action of the melt itself against the valve body in the event the melt advances more rapidly.

Abstract: A gas venting device for molding operations is disclosed having a valve for closing off a gas evacuation system from a mold when the mold cavity is filled with melt. A positive drive mechanism is provided for closing the valve, and a mechanism is provided for allowing the valve body to close more rapidly by action of the melt itself against the valve body in the event the melt advances more rapidly.

Abstract: A gas venting device for molding operations is disclosed having a valve for closing off a gas evacuation system from a mold when the mold cavity is filled with melt. A positive drive mechanism is provided for closing the valve, and a mechanism is provided for allowing the valve body to close more rapidly by action of the melt itself against the valve body in the event the melt advances more rapidly through the gas vent passages than expected.

Abstract: A flow control valve in which the main body of the valve and the first and the second cylinder is disposed coaxially with each other. The valve body disposed in the main body forms a first and a second separate chamber in the main body. A first and a second valve rod projecting from the valve body opposes the first and the second cylinder, respectively. The displacements of the pistons in the first and the second cylinder due to a fluid limits the displacement of the valve rods and the valve body. The opening and the closing of the passageway between the first and the second separate chamber is adjusted by the movement of the valve body, thereby flow of fluid being controlled.

Abstract: An arrangement for controlling an injection process for a die casting machine comprising an injection cylinder connecting to a plunger tip, a hydraulic circuit arrangement which supplies pressurized hydraulic oil to the cylinder at a plurality of rates of flow, and a control unit applying to the hydraulic circuit arrangement a plurality of signals when the plunger tip comes to a plurality of positions so as to change the middle speed of the plunger tip during one injection process, the hydraulic circuit arrangement providing with a plurality of combinations among a valve of the type of a pilot operated check valve which mounts a flow rate setting unit with a mechanical stopper and two position directional valve operated by the signals, and a method for operating the die casting machine comprising the steps of pouring melted metal into the injection cylinder, moving the plunger tip at a low speed to a position at which the level of the melted metal in the cylinder reches up to a portion near an entrance to a c