Glassmaking diameter sensing

Claim 1

In the process of refining molten glass wherein unrefined molten glass is continuously introduced into one end of an openended chamber, the chamber is continuously rotated to form a void in the molten glass, said void having an inclined surface and causing the gaseous inclusions to be removed from the glass to the void by the action of centrifugal force and the molten glass is continuously removed from the other end of the rotating chamber, the method of controlling the volume of glass in the chamber which comprises: positioning a movable probe withiN the rotating container, said probe comprising concentric tubes positioned relative to each other to provide an annular pressure passage and a central pressure sensing passage; moving the probe toward a point on the surface of the void while supplying air flowing under a constant pressure through the annular pressure passage; directing said air flow from the annular pressure passage toward the surface of the rotating molten glass at a surface of the void and sensing by return flow of air a predetermined change in air pressure in the probe as the probe apparatus approaches a predetermined position with respect to the surface of the void; continuously determining this difference in air pressure between the redirected air pressure in the sensing tube and the pressure of the constant pressure air supplied to the glass surface through the annular pressure passage; continuously comparing the pressure differences between the flows within a preselected range of pressure differences; operably and movably connecting said probe to a diaphragm motor; said motor having an air activatable diaphragm which divides the motor into two chambers; supplying air to one chamber of the diaphragm motor and countering the diaphragm movement by a pressure spring in opposition to the force of the air pressure supplied to the chamber of the diaphragm motor; controlling the air pressure supplied to the diaphragming motor so as to move the diaphragm against the spring and thereby continually urging the probe towards the surface of the rotating glass mass so as to keep the constant pressure stream within redirecting range of the surface of the molten mass; positioning a chamber flow control device within the outlet of the rotatable chamber; and operably connecting the flow control device so as to respond to any difference in pressure between the constant air pressure applied to the glass surface and the returned sensed air pressure which is outside the range of pre-selected pressure differences so as to move the flow control device to continually regulate the size of the exit of the chamber thereby regulating the volume of the molten glass within the chamber in response to the changes in air pressure differences directed towards the molten glass surfaces whenever the surface of the void changes to a location outside of the preselected range of pressure differences.