Abstract: A supplemental controller for a fiber glass bushing actively performs heating and cooling of a connected segment of the bushing which is otherwise controlled by a primary controller. In one embodiment, the supplemental controller performs heating by means of current injection into a connected bushing segment and cooling by means of current diversion from or around the connected bushing segment. Initial start-up and balancing operations can be performed without activation of the supplemental controller. In another embodiment of the invention, the supplemental controller heats a bushing segment by injecting current in-phase with current from the primary bushing controller and cools the bushing segment by injecting current out-of-phase with current from the primary bushing controller.

Abstract: A supplemental controller for a fiber glass bushing actively performs heating and cooling of a connected segment of the bushing which is otherwise controlled by a primary controller. In one embodiment, the supplemental controller performs heating by means of current injection into a connected bushing segment and cooling by means of current diversion from or around the connected bushing segment. Initial start-up and balancing operations can be performed without activation of the supplemental controller. In another embodiment of the invention, the supplemental controller heats a bushing segment by injecting current in-phase with current from the primary bushing controller and cools the bushing segment by injecting current out-of-phase with current from the primary bushing controller.

Abstract: A glass-fiber bushing including a bottom tip-plate and side walls surrounding the bottom tip-plate forming a container for molten glass. The bottom tip-plate including a plurality of tips arranged to permit molten glass to flow there through to produce a multiplicity of individual molten glass streams from which glass fibers may be formed. The glass-fiber bushing includes at least one tip-plate thermocouple having a platinum tube housing, a pair of thermocouple wires transversing the tube housing and terminating in a weld junction. The tube housing, thermocouple wires and the weld are attached directly to the tip-plate such that the thermocouple junction is formed directly at the tip-plate surface.

Abstract: A supplemental controller for a fiber glass bushing actively performs heating and cooling of a connected segment of the bushing which is otherwise controlled by a primary controller. In one embodiment, the supplemental controller performs heating by means of current injection into a connected bushing segment and cooling by means of current diversion from or around the connected bushing segment. Initial start-up and balancing operations can be performed without activation of the supplemental controller. In another embodiment of the invention, the supplemental controller heats a bushing segment by injecting current in-phase with current from the primary bushing controller and cools the bushing segment by injecting current out-of-phase with current from the primary bushing controller.

Abstract: An apparatus and method for making electrical resistance measurements of individual powered electrodes within a glass heating furnace is disclosed. The powered electrodes are energized in pairs with electrical power supplied at a relatively low frequency, causing electrical currents flow between the pairs of powered electrodes through a pool of molten glass so as to generate heat therein. A single reference electrode is also provided within the furnace. Each of the powered electrodes is sequentially paired with the reference electrode to permit voltage and current measurements to be made. To accomplish such measurements, a relatively small high frequency electrical signal is supplied to the powered electrode, in addition to the relatively low frequency heating power supplied thereto. As a result, a measurement current flows between the selected powered electrode and the reference electrode.

Abstract: A hierarchical distributive control system is disclosed. The lowest level of the system is a stand alone controller with hot plug in capability, which can accept either analog or digital signals, scale these signal with input subroutines, perform any one of a number of algorithms to produce control signals or can manually produce control signals and output these control signals as either analog or digital signals to field devices. A plurality of controllers communicates with an associated condenser over duel parallel digital communication buses with a full echo, verify communication routine. The condenser contains all records for all controllers under its supervision and can download control information into any replaced controller. A subhost is interconnected to a group of condensers and contains all records contained in all condensers under its supervision. All information can be uploaded from condensers to subhost or downloaded from subhost to condenser.

Abstract: A method for manufacturing mineral fibers comprises forming mineral fibers from molten mineral material, continuously discharging an auxiliary stream of molten mineral material, continuously measuring the temperature and the mass flow rate of the auxiliary stream, calculating the viscosity of the material using the measured mass flow rate and modifying a process parameter in response to the measured temperature and calculated viscosity of the auxiliary stream.

Abstract: A digitally controlled apparatus for varying the temperature of a glass fiber forming bushing over a period of time is disclosed. A clock generates timing pulses at a predetermined frequency to a BCD counter. The output signals from the BCD counter are fed to a comparator means. BCD output signals generated by a plurality of manually operable switch assemblies are also fed to the comparator means. The switch assemblies are set by an operator to generate a predetermined number related to the amount of time required to wind a strand of glass fibers upon a tube. The comparator means generates an output pulse when the count of the BCD counter equals the number set by the switch assemblies, then resets the BCD counter to zero. The output pulses from the comparator means are fed to a binary counter. The output lines from the binary counter are connected to a digital to analog converter. The converter generates an analog output signal which is proportional to the magnitude of the number from the binary counter.

Abstract: A bushing balance controller senses the temperature of each section of a multiple section glass fiber forming bushing by thermocouples or resistance (voltage drop) measuring techniques and injects electrical energy to all but one of the individual bushing sections and adjusts the supply of electrical energy to the entire bushing assembly thereby controlling the temperature of each individual section of the bushing. When thermocouples sensors are utilized, standard thermocouple driven temperature controllers may be utilized to provide a signal to a plurality of power packs, a primary power pack providing electrical energy to the entire bushing and smaller power packs controlling the injection of electrical energy to all but one of the bushing segments. A similar power pack and bushing control scheme accompanies the use of resistance (voltage drop) measurement techniques.

Abstract: This invention proposes a method of controlling the melting rate of a glass furnace to obtain substantially constant molten glass throughput. The furnace contains a pool of molten glass and a relatively thin layer of unmelted glass batch on the surface of the pool. The furnace contents are weighed, and the batch feed is controlled by the measured weight. In essence, the melting rate is determined by the thickness of the lighter, thermally insulated batch layer, since a thinner batch layer results in more heat loss through the batch and less batch melted by the cooler molten glass. Thus, a decrease in weight indicates more molten glass withdrawal and a lower melting rate, and batch is added to increase the molten glass temperature and to melt more glass batch. In the preferred embodiment, the furnace is electrically heated at a constant rate, and only the rate of batch feed is controlled to maintain substantially constant glass throughput.

Abstract: A panel assembly for terminating a plurality of thermocouple leads is disclosed. The panel assembly has sufficient mass that it can stabilize at the temperature of the surrounding air. All thermocouple termination posts are of a common metal such as copper so that all subsequent leads can be copper and thereby reduce termination errors due to subsequent thermoelectric effects. A temperature measuring device is embedded in the mass of the panel assembly for measuring the temperature of the termination points of the thermocouple leads. Recorder jacks are provided so that an external recorder may record the outputs of the thermocouple.

Abstract: A method for simultaneous compensation of a plurality of thermocouple signals where the thermocouple leads are terminated to dissimilar metals without using individual ice junctions for compensation of each thermocouple signal is disclosed. The thermocouple leads are all terminated to individual connectors as reference junctions which are held at the same temperature by a block of metal which stabilizes thermally with its environment. The temperature of the metal block is measured by an integrated circuit temperature transducer which produces an analog electrical signal proportional to the temperature detected. This signal is digitized and a microprocessor calculates the temperature of the metal block which is placed on a first data bus. Additional microprocessors are connected to the individual thermocouple leads. These microprocessors convert the thermocouple signals into an uncorrected digital temperature.

Abstract: A method of and apparatus for controlling the position of an electrode in relation to the upper surface of a body of molten glass in an arc glass-melting furnace comprising providing an alternating current of constant effective magnitude to the electrode, sensing the effective voltage supplied to the electrode, determining if the sensed voltage is within a predetermined range of voltages, and modifying the position of the electrode if the sensed voltage is not within the predetermined range of voltages.

Abstract: An electric glass-melting furnace is disclosed having a first embodiment comprising: a chamber adapted for holding a body of molten glass, such for withdrawing molten glass therefrom, an arc electrode positioned in the body of molten glass; first and second electrodes positioned in the body of molten glass; a reactance means comprising a coil wound on a core, such coil having a first and second end and a center tap, the first end of the coil being connected to the first electrode and the second end of the coil being connected to the second electrode; and means for supplying electrical power to the arc electrode and the first and second electrodes, a first terminal of the power supplying means being connected to the arc electrode and a second terminal being connected to the center tap. The current flow through the first and second electrode is equalized by the coil. This embodiment may be modified to use a three phase power supply for powering three arc electrodes.

Abstract: An apparatus is provided for controlling the amount of dry particulate matter and liquid added to a rotary pelletizer. A transducer placed within the pelletizer senses a characteristic of the mixed material in the pelletizer. This characteristic may be, for example, the level of the batch or the size of the pellets produced. The transducer signal is then conditioned to provide a modified signal level corresponding to a desired characteristic level and which varies about that level corresponding, for example, to the variations of pellet size about its desired size. The modifier contains two stages which may be used independently with the other stage being used as a straight through one to one amplifier. The two stages may also be used cooperatively to provide an intermediate signal. The intermediate signal can be used to operate a display device and as the input to a second amplifier. The second amplifier then provides a conditioned signal input into a larger control system.

Abstract: A method and apparatus are provided for controlling the amount of dry particulate matter and liquid added to a rotary pelletizer. A transducer placed within the pelletizer senses a characteristic of the mixed material in the pelletizer. This characteristic may be, for example, the level of the batch or the size of the pellets. The transducer signal is then conditioned to provide a signal level corresponding to a desired characteristic level and which varies about that level corresponding for example to the variations of pellet size about a desired size. That signal is added to a second signal representing the actual liquid flow into the pelletizer or added to a second signal representing actual dry particulate flow into the pelletizer and modulates that respective flow to maintain the input of either the dry or the liquid material into the pelletizer as necessary. Additionally, a set point signal can be provided as a constant signal representing desired dry particulate in flow or liquid in flow.

Abstract: This invention, is an apparatus for grading pellets produced by a pelletizer from dry particulate batch material and a liquid, as for a melting furnace such as a glass furnace. The pellets are sensed by passing the pellets adjacent a graded passage. When a pellet reaches a graded passage matching its size, the pellet drops through the passage and at the same time actuates a sensor indicating a pellet of that respective size. The sensor is connected to a counting device which then can provide, through an appropriate control device, a count of over or undersized pellets or the pellet distribution. This information then can be appropriately used by the control device to control the amount of dry batch material or the amount of water introduced into the pelletizer and to maintain the pellets within a desired range.

Abstract: A method of detecting electrode displacement in an opaque melt of heat softenable material heated by Joule effect through said electrode by monitoring the current, voltage and electrical displacement characteristics of a body of heat softenable material and the electrodes. A relatively rapid change in monitored resistance is an indication of and often characteristic of given changes in the geometric relationships between an electrode the heat softenable material and other electrodes which can accelerate the failure of a system if corrective action is not taken. Alarm indicators, instruction print out, and/or process controls can be actuated in response to a given current voltage or resistance change. Slumping of electrodes and the direction of the slumping is indicated by the nature and magnitude of changes detected on a long term basis at least of the order of days in length.

Abstract: A method of anticipating electrode failure by monitoring the current, voltage and resistance between electrode pairs in a Joule effect heating system. A relatively rapid change in monitored resistance is an indication of an incipient failure. Alarm indicators, instruction print out, and/or process controls can be actuated in response to a given current voltage or resistance change. Plural electrode pairs are monitored by multiplexing to provide a repetitive cyclic scan of the parameters between pairs. Distortion of current and voltage values is minimized, where selective portions of regular power pulses are gated for control of heating, and complex waveforms result by employing true r.m.s. values of current and voltage developed in true r.m.s. to d.c. converters.