Feasibility of In-Situ Process Monitoring of Glass Melt in Industrial Furnace using Microwaves

Abstract: Measurement of molten glass level in glass furnaces is a key issue for the control of the production process. Nowadays several different technologies shall be used for this purpose, with their advantages and drawbacks. In this paper a novel level sensor is proposed, it is based on radar interferometry technique, and it is designed to provide high accuracy measurements, high reliability and a very low maintenance.

Abstract: An ultrasonic level measurement system which provides a continuous digital readout over a range of 3 to 180 inches, was tested in 500°F liquid sodium. The system proved to be accurate and reliable, required no initial warm-up period and experienced no long term drift. Modifications can extend the present operating temperatures to greater than 1200°F.

Abstract: Design and demonstration of an ultrasonic buffer rod for high temperature fluid especially for the molten glass were studied. Material selection guide for glass melts was established focusing on high temperature strength, attenuation and acoustic impedance. Durability and wettability of ultrasonic buffer rod have been tested for several materials. Frequency of the ultrasound was chosen considering the transmission characteristic of the buffer rod which was investigated employing three dimensional FEM code. The buffer rod tested has tapered shape and cladding on the side wall as a further suppression of trailing echo. Sound velocity and attenuation coefficient measurements in a temperature range of 1000–1200 °C were then demonstrated utilizing the designed buffer rod. Signal processing technique to eliminate remained trailing echoes was also performed. Applicability of the ultrasonic measurement using the buffer rod is discussed.

Abstract: A specially designed air-cooled compact antenna is proposed for non-contact real-time radio detection and ranging (RADAR)-level measurement in furnace. 3-D modeling is used to optimize the surface profile of the RADAR antenna for beam symmetry and low sidelobe level over 20–24 GHz. The fabricated RADAR sensor deployed in mono-static mode has 0.19-mm measurement error for a static target. Measurements in a closed furnace at 1100 °C demonstrate the feasibility of non-contact in-situ monitoring of the level of molten metal for long duration (11 hours) without degradation in the sensor performance.

Abstract: As a part of the indigenous development of the Induction Skull Melting (ISM) technology, a set of numerical simulations was carried out initially to arrive at the design parameters of a segmented cold crucible Based on these parameters, an ISM facility comprising a water-cooled segmented copper crucible with in-situ casting module, induction heating power supply system, cooling water recirculation system, vacuum chamber with vacuum delivery system and associated instrumentation & control units was built The ISM facility was successfully tested for melting and homogenizing different metals and alloys