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Show Lowest Power Requirements Environmental F actors,Combustion/Blower Noise Minimal Operative Involvement/requirement Minimal Maintenance THE GLASS INDUSTRY Despite competition and some replacement from such materials as coated steels, aluminium, plastics, paper cartons and others, Glass does, and always will, playa vital role in any modern society. Great improvements have been introduced such as the Float Glass Process from Pilkingtons in the UK which has revolutionised flat/plate glass production, quality and cost. T. V. TUBE PRODUCTION The production of Television Tubes is a prime example of advancing technology to reduce costs and production losses. Carried out on In-line Exhaust Machines (IEM), the Vacuum Process of T. V. Picture Tubes is the KEY manufacturing process of the product and involves a complex technique which will be briefly described. The cost content of the tube prior to the Vacuum Process includes 95% of the materials and labour of the finished tube. A 1% tube loss in the final process on a typical finishing line would cost over 300 000 dollars/year. The Vacuum Process gives the life and technical performance of the tube. In-line Machine reliability and involving rigid process control/temperature are essential during the vacuum bake of the picture tube including:Outgassing of the electron gun by Radio Frequency Induction Heating at controlled heating rates to a temperature approaching 800°C. F ormation or acti vation of the cathode emissi ve coating:controlled conversion of Barium Carbonate to its oxide. Note this may be completed after the exhaust process depending on subsequent activation and ageing process technology. Final seal-off of the product from the Vacuum System. Ideally once each stage of the process has started, for best operating efficiency and technical product performance, it should continue uninterrupted, with adequate vacuum recovery time between each process stage. Such control systems range from the relati vely simple vacuum/electrical interlocks to the sophisticated microprocess control. Each T.V. tube is loaded on to a special transporter cart which carries the tube through the I.E.M. Oven which is controlled in a series of zones to achieve the controlled heating and cooling of the tube during the process stages. 274 At one of the largest T.V. manufacturers in the United States, Electricity was used on their I.E.M.'s. The first Unit was successfully converted to Direct Gas Firing in 1984 using one of a new generation of Gas Burners. The Oven has 21 zones each 10 feet in length but the total length of this hairpin shape oven is approximately 400 feet including the cooling zones. Direct replacement of the electric heater elements by a single burner of 250 000 Btu/hr capacity using Natural Gas proved totally satisfactory. These Burners are basically very simple utilisng a stainless steel fire-tube, thus eliminating all refractory from construction. This stainless steel firetube can be produced to suit any wall thickness and the combustion point is taken forward to the tube end to introduce the heat where it is required - in the process. For high temperature applications Silicon Carbide Firing Tubes are employed. Input control is by simple motorised air flow control butterfly valves with pressure impulse lines direct loading gas flow proportionator valves. Ignition is by direct spark and flame proving by flame Rod ionisation. Turndown capabilities of 15:1 are achieved on ratio using 14 w.c. high fire air pressure thus reducing noise emission and fan power/noise. The T.V. tubes pass through the oven at the rate of 128/hr and are resident for 116 minutes. Heat up 36 mins 75°F to 750°F Soak 20 mins at 750°F Cool down 60 mins 750°F - 3000 F Zone Temp. variation :t 5°C from set point Gas proved as controllable as Electricity and an added advantage was the pressurisation of the Oven Chamber with the combustion gases thus limiting ingress of cold air flow into the Unit through the bottom slot to the detriment of the temperature desired profiles and risk of chilling of tubes. The atmosphere generated by the combustion gas has had no detrimental effect on tube treatment/quality. Gas flow within the Oven is a critical factor on the treatment cycle. Studies of thermal efficiency comparing the previous energy sources and Gas have indicated a satisfactory reduction in energy costs when all factors are considered. This firing technique is operating successfully in many locations Worldwide. Fluorescent Tube Production - Ceramic Fibre Infra-Red Generator Applications. Another essential commodity to-day is Fluorescent Tubes. These are produced on continuous lines and each line frequently produces 2 or more different length tubes to suit Market demand. The application of Fluorescent Powder Coating |