Melting and holding furnace

A melting and holding furnace, comprising:

• a melting furnace main body;
• and
• a material input mechanism supplying at least one of molten metal and a metal block to the melting furnace main body,
• wherein the melting furnace main body includes:
• a melting chamber for holding the molten metal;
• a molten metal receiving chamber communicating with the melting chamber and being supplied with the at least one of the molten metal and the metal block from the material input mechanism;
• a pumping-out chamber communicating with the melting chamber and being configured for tapping the molten metal that is introduced from the melting chamber into an external casting machine;
• and
• a molten metal heating mechanism heating the molten metal in the melting chamber,
• wherein the melting chamber includes a melting chamber lid that is installed so as to seal an upper opening of the melting chamber without forming a space between a surface of the molten metal and itself,
• wherein the material input mechanism includes a molten-metal surface level sensor configured to at least detect that a surface height position of the molten metal in the pumping-out chamber has reached a lower limit set to be above a lower surface height position of the melting chamber lid and at least detect that the surface height position of the molten metal in the pumping-out chamber has reached an upper limit set to be above the lower surface height position of the melting chamber lid, the upper limit being above the lower limit, and wherein, when the molten-metal surface level sensor detects that the surface height position of the molten metal in the pumping-out chamber has reached the lower limit, the material input mechanism supplies the molten metal receiving chamber with the at least one of the molten metal and the metal block until the molten-metal surface level sensor detects that the surface height position of the molten metal in the pumping-out chamber reaches the upper limit so that the surface height position of the molten metal in the pumping-out chamber is always kept above the lower surface height position of the melting chamber lid and the molten metal is always in contact with a lower surface of the melting chamber lid.