Abstract: A pressure controlling apparatus controls a pressure in a container capable of storing a molten metal and supplying the molten metal to an outside using a pressure difference and includes: a supplying portion for supplying a compressed gas to be supplied to the container; a flow passage for supplying the compressed gas from the supplying portion to the container; a first switching valve, being inserted into the passage, capable of manually switching a first mode that enables the passage of the gas between the supplying portion side and the container side and a second mode that enables the passage of the gas between the container side and the outside; an exhausting portion for exhausting a gas from the container; and a second switching valve for switching a pressure applying mode for applying a pressure to the container and an exhausting mode for exhausting the gas from the container.

Abstract: When emergency shutdown operation becomes necessary while a gas used for applying pressure to the in of the container is being supplied from the receiver tank to the container, the lever is turned and the three-way valve is switched to the second mode. Then the first valve opening in the three-way valve is blocked and the supply of the gas used for applying pressure to an inside of the container from the receiver tank to the container is stopped. In addition, since the gas can flow between the second valve opening on the container side and the third valve opening opened to an atmosphere in the container is released to an atmosphere. In other words, in the present invention, the supply of the gas used for applying pressure to the in the container can be stopped and, in the same time, in the container is released to the atmosphere with a single action, namely, manually turning the lever provided close to the driving seat. Therefore, the safety level of the system is very high.