Method of manufacturing glass, and stirring device

A method of manufacturing glass, comprising:

• a melting step for melting a glass starting material and obtaining molten glass;
• a stirring step for stirring the molten glass obtained in the melting step;
• and a molding step for molding glass from the molten glass stirred in the stirring step;
• wherein in the method of manufacturing glass,
• the stirring step comprises a first stirring step for stirring the molten glass while the molten glass is directed upward from below in the interior of a first stirring tank, and a second stirring step for stirring the molten glass that was stirred in the first stirring step while the molten glass is directed downward from above in the interior of a second stirring tank;
• the first stirring tank is provided with a first chamber, a first stirrer for stirring the molten glass within the first chamber, and a first discharge pipe capable of discharging the molten glass from the bottom of the first chamber;
• the second stirring tank is provided with a second chamber, an outflow port configured to allow the molten glass to flow from the bottom of the second chamber into a downstream conduit, a second stirrer for stirring the molten glass within the second chamber, and a second discharge pipe capable of discharging the molten glass from the liquid level of the molten glass within the second chamber;
• the side of the first stirring tank in an upper part thereof is connected by a connecting pipe to a side of the second stirring tank in the upper part thereof;
• the molten glass is transferred from the first stirring tank to the second stirring tank via the connecting pipe;
• in the second stirring step, the second stirrer rotates about a second shaft as a rotation axis, whereby second ancillary plates create, in the molten glass, a flow in the radial direction of the second shaft, and the second ancillary plates positioned between second support plates of second blades disposed in two adjacent tiers create, in the molten glass, a flow in the same direction;
• and
• in the second stirring step, upward from the second support plates of the second blade positioned in an uppermost tier, the second ancillary plates arranged on the upper principal face of the second support plates of the second blade positioned in the uppermost tier create a first flow for moving the molten glass towards the second shaft from an inner wall of the second chamber, and create a second flow for causing the molten glass moved by the first flow to ascend along a side face of the shaft.