Abstract: An edge closure system is presented herein wherein a portion of the closure edge of the filter bags leading to the outlet pipe aperture are provided with mating snapping closures, allowing to sealingly close the length of the edge of the fabric leading to the outlet pipe aperture simply by engaging the male and female components of the snapping closures. Moreover, an outlet pipe closure system is also presented herein using a combination of a tongue mounted internally to one of the sides of the fabric forming the bag in a manner to be wrappable around at least a corresponding portion of the outlet pipe, and a fabric hood mounted externally and overlapping both sides of the bag at the outlet pipe aperture, which cooperates with the tongue to seal the interface between the outlet pipe and the bag when held in position.

Abstract: An edge closure system is presented herein wherein a portion of the closure edge of the filter bags leading to the outlet pipe aperture are provided with mating snapping closures, allowing to sealingly close the length of the edge of the fabric leading to the outlet pipe aperture simply by engaging the male and female components of the snapping closures. Moreover, an outlet pipe closure system is also presented herein using a combination of a tongue mounted internally to one of the sides of the fabric forming the bag in a manner to be wrappable around at least a corresponding portion of the outlet pipe, and a fabric hood mounted externally and overlapping both sides of the bag at the outlet pipe aperture, which cooperates with the tongue to seal the interface between the outlet pipe and the bag when held in position.

Abstract: The pleated filter bag, which can be used in a bag-house type dust collector, is elongated and has a longitudinal hollow center with an open end, and a pleated filter wall circumscribing the hollow center. The pleated filter wall has a felt such as PTFE fibers felted onto an apertured and pleatable scrim which can be made of metal, and having a permeability lower than a permeability of the scrim. A membrane of lower-permeability material, such as an E-PTFE membrane, covers the support felt on the outer side of the bag.

Abstract: The pleated filter bag, which can be used in a bag-house type dust collector, is elongated and has a longitudinal hollow center with an open end, and a pleated filter wall circumscribing the hollow center. The pleated filter wall has a felt such as PTFE fibers felted onto an apertured and pleatable scrim which can be made of metal, and having a permeability lower than a permeability of the scrim. A membrane of lower-permeability material, such as an E-PTFE membrane, covers the support felt on the outer side of the bag.

Abstract: The pleated filter bag, which can be used in a bag-house type dust collector, is elongated and has a longitudinal hollow center with an open end, and a pleated filter wall circumscribing the hollow center. The pleated filter wall has a felt such as PTFE fibers felted onto an apertured and pleatable scrim which can be made of metal, and having a permeability lower than a permeability of the scrim. A membrane of lower-permeability material, such as an E-PTFE membrane, covers the support felt on the outer side of the bag.

Abstract: The system (10) and the method are used for forecasting the electrical conductivity of an anode (12) for aluminum production before the anode (12) is baked. In the system (10), at least one receiving coil (20,22) is coupled to an electromagnetic field emitting unit (14,18). A sensing device (30) is connected to the receiving coil (20,22), the sensing device (30) outputting a signal indicative of a variation of the electromagnetic field received by the receiving coil (20,22) as the crude anode (12), or a portion thereof, passes inside the receiving coil (20,22). A value indicative of the electrical conductivity of the anode (12) is then calculated using the signal from the sensing device (30) and signals previously obtained using reference anodes (12). This way, the electrical conductivity of the anodes (12) can be forecasted before the crude anodes (12) are baked.

Abstract: The system (10) and the method are used for forecasting the electrical conductivity of an anode (12) for aluminum production before the anode (12) is baked. In the system (10), at least one receiving coil (20,22) is coupled to an electromagnetic field emitting unit (14,18). A sensing device (30) is connected to the receiving coil (20,22), the sensing device (30) outputting a signal indicative of a variation of the electromagnetic field received by the receiving coil (20,22) as the crude anode (12), or a portion thereof, passes inside the receiving coil (20,22). A value indicative of the electrical conductivity of the anode (12) is then calculated using the signal from the sensing device (30) and signals previously obtained using reference anodes (12). This way, the electrical conductivity of the anodes (12) can be forecasted before the crude anodes (12) are baked.

Abstract: The filtration cartridge comprises a filtration element and a heat-resistant extension band having a first and a second longitudinal edge. The first edge of the extension band is attached along an edge of the filtration element. In a first embodiment, a metallic cast end member is formed by immersing the second edge of the extension band into molten metal. The molten metal is then allowed to solidify with the second edge of the extension band embedded therein. In a second embodiment, the extension band is squeezed on a porous inner core and an end plate is welded on the end of the inner core. Providing filtration cartridges with a metallic end member allows increasing their resistance to mechanical shocks and increasing their maximum operating temperatures.

Abstract: The filtration cartridge comprises a filtration element and a heat-resistant extension band having a first and a second longitudinal edge. The first edge of the extension band is attached along an edge of the filtration element. In a first embodiment, a metallic cast end member is formed by immersing the second edge of the extension band into molten metal. The molten metal is then allowed to solidify with the second edge of the extension band embedded therein. In a second embodiment, the extension band is squeezed on a porous inner core and an end plate is welded on the end of the inner core. Providing filtration cartridges with a metallic end member allows increasing their resistance to mechanical shocks and increasing their maximum operating temperatures.

Abstract: The filtration cartridge comprises a filtration element and a heat-resistant extension band having a first and a second longitudinal edge. The first edge of the extension band is attached along an edge of the filtration element. In a first embodiment, a metallic cast end member is formed by immersing the second edge of the extension band into molten metal. The molten metal is then allowed to solidify with the second edge of the extension band embedded therein. In a second embodiment, the extension band is squeezed on a porous inner core and an end plate is welded on the end of the inner core. Providing filtration cartridges with a metallic end member allows increasing their resistance to mechanical shocks and increasing their maximum operating temperatures.

Abstract: The system and the method are used for detecting a level of liquid metal at a given location, such as a launder set between an holding furnace and a casting pit. The system comprises an emitter coil and a receiver coil in a side-by-side configuration and in close proximity of the location. In use, an AC signal is applied to the emitter coil for producing an alternating magnetic flux. At least a part of the magnetic flux passes through the location where the level of liquid metal needs to be measured and goes back into the receiver coil. The signal in the receiver coil is monitored and the data are conveyed to a control module which determines the level of liquid metal from the variation of the signal in the receiver coil. The coils of the system are advantageously provided with respective core elements having a high magnetic permeability and which are configured and disposed to channel the magnetic flux.

Abstract: The system and the method are used for detecting a level of liquid metal at a given location, such as a launder set between an holding furnace and a casting pit. The system comprises an emitter coil and a receiver coil in a side-by-side configuration and in close proximity of the location. In use, an AC signal is applied to the emitter coil for producing an alternating magnetic flux. At least a part of the magnetic flux passes through the location where the level of liquid metal needs to be measured and goes back into the receiver coil. The signal in the receiver coil is monitored and the data are conveyed to a control module which determines the level of liquid metal from the variation of the signal in the receiver coil. The coils of the system are advantageously provided with respective core elements having a high magnetic permeability and which are configured and disposed to channel the magnetic flux.

Abstract: Apparatus for and a method of measuring the temperature of molten aluminum or aluminum alloys. The apparatus comprises a temperature measuring device, usually a thermocouple, contained within a protective tubular sheath, the sheath enclosing the temperature measuring device at least to a point above the point of maximum immersion in molten aluminum during use of the apparatus. The sheath comprises at least one inner layer closed at one end, and an outer layer, the outer layer being made of steel or cast iron, and the inner layer being made of a continuous refractory material. The outer layer and the at least one inner layer are free of discontinuous (refractory) refractory materials between them. The continuous refractory material may be, for example, a carbon fiber-reinforced carbon or graphite fiber-reinforced calcium silicate refractory, and is resistant to failure in, i.e. penetration by, molten aluminum or aluminum alloy.

Abstract: An ultrasonic device for detecting concentrations of solids or positions of solid/liquid interfaces in liquid media, particularly Bayer process liquids. The device comprises at least one piezoelectric element provided with electrodes; electrical circuit elements connected to the electrodes for conveying electrical signals, in use, to and from control apparatus; an ultrasound-transparent window, made of glassy carbon, positioned adjacent to the or each piezoelectric element; a protective matrix, preferably of epoxy resin, embedding and surrounding said the or each piezoelectric element and the electrodes while allowing ultrasonic waves to pass through the or each adjacent window to or from the piezoelectric element, and an external protective cover, preferably comprising an elastomer that is resistant to caustic alkali and has a smooth and non-porous surface, forming an exterior of the device except at the or each window.

Abstract: A temperature measuring device for measuring the temperature of an abrasive particulate material of the type found, for example, in rotary calcining kilns and the like. The device comprises a temperature sensor producing an indication of a temperature to which the sensor is exposed, circuitry or the like for connecting the temperature sensor to remote equipment for converting the indication to a recognisable form and a protective element shielding the temperature sensor from damage by the abrasive particulate material. The protective element comprises a layer of ceramic material having a matrix of alumina reinforced with 5 to 50% by volume (based on the total volume of the ceramic material) of particles of silicon carbide having an average size, at least in two dimensions, within the range of about 5 to 60 microns. The protective element provides good abrasion, heat-shock and mechanical resistance while exhibiting sufficient thermal conductivity to avoid undue inaccuracies in the temperature measurements.

Abstract: A process for producing silicon carbide platelets having a size of 20 .mu.m or less, and the platelets so produced. The process comprises reacting particles of carbon from a source containing less than 0.2% by weight of iron, with silica or a silica precursor at a temperature in the range of 1800.degree.-2100.degree. C. under an inert atmosphere in the presence of 0.2-10% by weight of an oxide or oxide precursor of Ca, Mg, Al, W, Ce or Cu; 0.1-10% by weight of boron, relative to the weight of SiO.sub.2, and preferably 0.1-10% by weight of the reaction mixture of alpha silicon carbide particles having a size of 5 .mu.m or less. The carbon is preferably in the form of particles of less than 50 .mu.m and the silica or precursor is preferably in the form of particles of less than about 45 .mu.m. The weight ratio of silica to carbon is greater than 1.76:1. The carbon source is preferably a pure form of carbon, e.g. graphite or amorphous carbon.

Abstract: A process for producing small particles of aluminum nitride suitable for sintering and the particles thus-produced. The process comprises reacting particles of gamma alumina, or a precursor thereof, of less than 1 micron in size with a stoichiometrical excess of finely divided carbon in the presence of nitrogen, or a precursor which provides nitrogen in the reaction conditions, first at a temperature in the range of 1550.degree. to 1700.degree. C. for a period of between 1 and 6 (preferably 1 to 4) hours and then at a temperature in the range of 1750.degree. to 1850.degree. C. for a period of 1 to 4 (preferably 1 to 2) hours, followed by cooling said reaction mixture and reheating to a temperature in the range of 500.degree. to 700.degree. C. in an oxygen-containing atmosphere, and maintaining the temperature until excess unreacted carbon is removed.

Abstract: A process for producing unagglomerated single crystals of aluminum nitride of low oxygen content having a size of at least 10 microns suitable for the reinforcement of metal, ceramic and polymeric matrix composite materials, and especially metal matrix materials. The process involves producing a reaction mixture of alumina (or a precursor), carbon (or a precursor), and an alkali metal oxide (or precursor such as a carbonate) as a crystal growth promoter or catalyst. The alkali metal oxide is present in an amount required for the formation of crystals of the required size, preferably in the range of 10-60 microns. The reaction mixture is subjected to a preheating step under nitrogen at a temperature in the range of 1600.degree.-1700.degree. and is then subjected to a heating step under nitrogen at a temperature in the range of 1800.degree.-1950.degree. C. This two-stage heating process ensures that the resulting crystals are of low oxygen content and thus good thermal conductivity.

Abstract: A process for producing silicon carbide platelets having a size of 20 .mu.m or less, and the platelets so produced. The process comprises reacting particles of a non-graphitizable form of hard carbon containing 0.5-1.5% by weight of aluminum and at least 0.2% by weight of iron (preferably anthracite coal, most preferably Pennsylvania anthracite), with silica or a silica precursor at a temperature in the range of 1800.degree.-2100.degree. C. under an inert atmosphere. If the carbon contains 0.2-1.0% by weight of iron, 0.1-10% by weight of boron, relative to the weight of SiO.sub.2, is added (if not already present). In the invention, 0.1-10% by weight of the reaction mixture of alpha silicon carbide particles having a size of 5 .mu.m or less are added to the reaction mixture to control the size of the platelets so that a majority have a size of less than 20 .mu.m. The carbon is in the form of particles of less than 50 .mu.