Brazil FBTC245239 glass tempering furnace

1. Brief Introduction The furnace consists of loading table, heating furnace, flat quenching section, unloading table, blower system and control system. 1.1 Loading Table The loading table consists of frame, conveyor system and lifting system. It is use for laying glass, when the glass sheet is laid on the right position and the size of the glass sheet is correct, the glass sheet can go to next step entering the heating furnace. 1.1.2 Conveyor system The loading table use frequency inverter with encoder to control conveyor system. So the glass sheet can be transported forwards and stopped in ready-to-enter-furnace position stability when the sensor detects it. According to the sheet’s size, its moving distance and speed each time can be altered through man-machine interface on the computer. Length of glass loading shall be measured by the sensor installed in front of the furnace and encoder mounted on drive system. There are two types conveyer rollers in the loading table, one is rubber roller, which is made of steel and covered with natural rubber, another is fiberglass ropes roller which is made of steel and covered with fiberglass ropes. The fiberglass ropes rollers are mounting nearby the heating furnace. These conveyor rollers can prevent glass from impact and scratching. 1.1.3 Loading Lifting System There is one lifting system in the loading table, it is use to assist in loading any large-sized glass, the lifting system consists of side roller, ball roller and pneumatically system. First of all, the lifting table lifts up by pneumatically, with the assistance of side rollers on the side of loading table, glass sheet shall be positioned on the right position by the ball rollers. Then the sheet is laid on the conveying rollers after the lifting mechanism lowers down. Glass sheets shall be placed on the loading table in the way recommended in the Tempering Process Manual and conveyed into the furnace. 1.1.4 Features of Loading Table: a. Driving adopts belt transmission, it’s easy mounting and dismounting, and also for maintenance conveniently. b. Frequency inverter is use to control the conveyer, so the speed is easy to alter. c. Lifting system is easy to operate and adjust, it can prevent the big-size glass from scratching, and rise the efficiency. 1.2 Tempering Furnace: The major part of tempering furnace is frame, heating system, insulation system, heating system, lifting furnace for maintenance system, heat-balancing system, and conveyor system. 1.2.2 Heating System There are many heating elements in the upper and the lower of the furnace, they divide into so many zones, each zone has one thermocouple to test the temperature and then send the sign to the PLC, so the temperature inside the furnace is easy to control and the temperature almost the same as setting. Besides heating element, there are many radiation sheet on the lower of the furnace. The radiation sheet is good at heat distortion, abilities of high-temperature and anti-corrosion, these are better than the ordinary one. 1.2.3 Insulation System The heating insulation material is aluminum silicate; it is light weight, fire-resistance and high heating protection performance. In the furnace there are many type of this material, different place use different type, and use our way to assemble. these let the furnace have good effective energy-saving and heat preservation. Due to good heat insulating performance of FUSHAN furnace, the temperature of outside furnace surface if less than 45 degree Celsius under the usual room temperature. When the furnace temperature is held for 12 hours after the heating power is turned off, the furnace temperature shall only decrease by about 150 degree Celsius. The programmed furnace temperature shall be reached after the furnace is heated for 30 minutes. 1.2.4 Furnace Lifting For Maintenance System The lifting system is made up of ball screw, umbrella gear, deceleration mechanism, motor, upper and lower limitation security protecting devices etc. This lifting system is very easy to assemble and adjust, and maintenance is simple. The top furnace can lift up steadily and silence. It has upper and lower limitation security protecting devices that ensure the lifting system is safety. 1.2.5 Heat-balancing System When glass is being heated in the furnace, the lower surface of sheet gets the heating conduction by three ways including convection, radiation and conduction from the ceramic rollers while the upper surface shall only absorbs heat from convection and radiation. The coated glass, especially the coated up-curved membrane of LOW-E glass, 70 percents of infrared are held up without absorbing so that the absorbed heat between the upper and lower surface of glass is seriously unbalanced. The heat conducted from ceramic rollers makes the temperature on the lower surface of glass more quickly than the upper surface, which even in the worst case, could bring the glass warped and coatings on the glass burnt in the furnace. Therefore, heat balancing system shall be installed, in which, air is forcedly injected onto the upper surface of glass from the heat balancing tubes, which removes the unbalance between the upper and lower surface of glass as well as shortens the heating time. And also ours heat-balance system adopts PLC control and adjust automatically after heating system testing, and also its adjustment is according to the heated level of glass in the furnace, to be ensure the heating evenly of the glass in the furnace more efficiently. 1.2.6 Conveyor System a. we generally use frequency inverter with encoder to control conveyor system, we can adjust the speed easily and the glass can move on the right position accurately, so the transportation is steadily, this structure given with the best quality products. b. O-ring belt to drive, this driving device can reduce the impact onto the ceramic rollers from the vibration of driving system, but It cannot ensure each roller moving synchronously. If rollers don’t move synchronously, the relatively sliding occurs between the glass sheet and rollers so that the lower surface of the sheet will be scratched slightly when the glass sheet moves forwards and backwards in the furnace; meanwhile when multiple sheets of glass are heated, deflection of glass sheets’ position and collision between them will occur. As for the glass of irregular shape, if the deflection occurs due to the uneven motion by force, even if the sheet cannot be moved out of the furnace, the loading capacity as well as the rate and quality of finished products shall be affected. Besides the O-ring, FuShan equipped with special structures which help to prevent product errors totally and showing the best tempering quality. c. Conveyor for ceramic driving system equipped with UPS system, which used for solving the case once power off suddenly when the line under running. UPS system can drive the ceramic rollers in 30 minutes when power off. Once glass in the furnace, sudden power off, UPS started on to help glass move out from furnace automatically and keep the ceramic roller will be not damaged. The line also equipped with hand driving device which help to move out the glass by manual when power off. d. The ceramic roller is one importance part of the conveyor system. Because the glass moves on the ceramic rollers when being heated, so the quality of final products can be affected by the property and quality of the ceramic rollers. Therefore, some factors of the selected rollers should be considered: 1) the weight of carrying glass; 2) the thermal conduction speed on to the glass;3)the roughness of the surface; 4) well-proportioned material. The tempering process demands the heating balance onto the upper and lower surface of glass. Due to the influence by the difficulty of manufacturing and the cost, some manufacturers select thicker rollers, which give more heat onto the lower surface of glass so that the edges of glass are resulted in warping. In this case, glass’s bary center concentrates on the narrow central bottom of glass. Therefore, the inter-friction between glass and ceramic rollers can be caused so that slightly scratch occurs on glass that is so-called the phenomena "streaks”. The high precision ceramic rollers selected by FUSHAN shall solve the problem. e. About the Rollers Supporting Mechanism, some company's ceramic rollers were installed under the cross sections of the upper and lower parts of furnace body conveniently. With this structure, it was difficult to determine the leveling of rollers and no good for mounting, dismounting and maintenance. When dismounting rollers, at least one man has to climb into the furnace and this action tends to damage the heat-insulating layer and the ceramic rollers. But now, as for ours tempering line it’s no need send any one to climb into the furnace for dismounting rollers, because we have designed special device for dismounting /mounting for customers. The ceramic rollers of FUSHAN tempering furnace are located between the upper and lower parts of furnace body (in the middle). This will prevent it from the defects mentioned above and the glass can be put out of the furnace immediately in case of emergency so that the conglutination of glass onto rollers shall be avoided. f. We have a special transporting mechanism for ceramic rollers equipped; the equipment shall promptly and easily assist in dismounting/mounting ceramic rollers without man climbing into the furnace. This mechanism shall help save over half of the time in stopping the manufacturing. 1.3. Flat quenching Section Flat quenching section consists of frame, nozzle system, lifting system and conveyor system. 1.3.1 Frame The frame of the flat quenching section is made by good quality steel. The structure of it is easy to assemble the other part of the flat quenching section and easy for maintenance. 1.3.2 Nozzle System The nozzle system is divided into upper and lower part, the upper and lower part are almost the same, it is good to assemble and maintain. According to the processing requirements of tempering glass we designed the nozzles specially (the material is aluminum alloy). This nozzle designing improved the efficiently tempering glass and reduced the energy consumption and also can reduce the rainbow. 1.3.3 Lifting Nozzle System We use frequency inverter with encoder to control the lifting system, the upper and lower part of the nozzle system can adjust separately. This lifting system can ensure the upper and lower part of the nozzle system can move to the position as we set accurately. When the heated glass is entering to this section, the upper and lower part of the nozzle get close automatically, different thickness of glass need different distance between the upper and lower part. Accurate lifting system can ensure the distance between the upper and lower part correct, it is one important factor to have good quality final product. 1.3.4 Conveyor System. The rollers is specially processed steel rollers with heat-resistant fiber ropes, it shall not make the ropes gradually shifted during their running. Therefore the steel rollers ensure the correct direction of glass when moving in order to avoid the collision between the glass sheets at this position. Specially processed steel rollers with heat-resistant fiber ropes, in order to avoid the glass on the rollers are wave bending and offset we made specially designing and processed and installed for the rollers and rope. 1.4. Traverse Bent Quench Section Traverse bent quench section includes: Rack, conveyor frequency converting device which ready to adjust precisely the rotation and clockwise and anti-clockwise interval, upper and lower blowing system with absolute-value encoder for control the lifting position with precision. Upper quench roller pressing device for adjustment of small radius products with over-length edge. Separate upper and lower air array cooling device with adjustable stroke cylinder to control blowing distance. Simple manual structure for adjusting the arc of upper bent quench. Compensated-adjusted device of lower bent quench with bending shape and arc structure to be adjusted by bending motor. Locator to rectify the glass skewing when enters in the quench. 1.5. Control System: 1.5.1 The control system includes temperature control system and process control system. Industrial Advantech Computer used for temperature control system, and Omron PLC used for process control system. They will not be easily affected by the environmental temperature, humidity, noise, magnetic region, etc. during running, which ensures the stability of the control system. The peripheral equipments (including electric measuring system, execution units and pneumatic gages) are all chosen from the famous China products or abroad. The hardware has proper configuration with advanced technology. The software functions of the system control are strong with high reliability. The operation interface suitable for man-machine dialogue is what the operator wishes to get. 1.5.2 The input/output testing window makes it easier for examination and debugging. The equipment trouble detecting function provides a full basis for maintenance. The peripheral component, including electrical and pneumatic measurement, heating elements, adopts imported or national products. The configuration of hardware is reasonable and the technology level is advanced. 1.5.3 The control system includes the control of the driving system and the temperature. Monitor-Samsung flat full colorful screen, does not only ensure a long life for running, but also a comfortable operation. Adopting the PLC (Programmable Logic Controller) OMRON made in Japan, which ensures a reliable running and a stable processing. The heating control adopts matrix heating and multi-power adjustment, which makes it easier for even heating. 1.5.4 The special design of an independent temperature controlling system avoids overheating and damage to furnace caused by misplay while heating, which greatly improve the security for furnace. The system has read and writes function for processing parameters, automatic control, unit machine operation and test as well as self-diagnosis connected with alarming system. Emergency power scheme ensures a safe unloading when you have a power cut. The details processing data as follow: Process parameters storage and re-call, such as glass thickness, size, color, glass type and maybe different sources of float glass etc. Whenever tempering a new order for different thickness, size, color, type, source etc., the process parameters are entered and the system will memorize these process data. Next time, when tempering a similar or identical order, the machine will automatically recall and use the stored processing data to produce. The system can store many sets of parameters. Controller for roller drive system, Controller for the temperature control, Controller for quenching control, The abnormality alarm system warns when problems occur, and indicates how to deal with the trouble, The main industrial control computer is installed with the terminal at the control desk. A color display screen provides the users with analogue process status: main screen, process parameters screen, operation and maintenance screen and system parameters screen. The system has read-and-write function for process parameters, automatic control, unit machine operation and test as well as self-diagnosis, and display alarm function. a) The main drive control system is operated through a computer controlled inverter system. All sections of system are fully controlled and coordinated. b) The main screen is the page displayed on the monitor during normal production. The contents displayed directly in English are the status of glass in the furnace and driving system, temperature in each zone, heating time, quench and cooling, actual pressure and set-point of fans and total length pieces of glass in the furnace. The operator uses this screen during production. The process parameters screen records the designed moving distance of the loading table when the pedal switch is actuated by the operator, temperature set-point of upper and lower furnace, pressure set-point of fans, and quench time and cooling time set-point. These screens are frequently used for normal operation. Maintenance people to test every part of the system use the maintenance screen. The system parameter screen is used by the manufacturer of the machine for test, and should be used not by anyone for security reasons. The system also has some supplementary screens, which will not be explained here. 1.7 Characteristics Up-to-date heat preservation technology is used in the furnace. The furnace has a good thermal insulation and lower power consumption, adopts advance heating way and aptitude working stages automatically. The ceramic rollers are excellent quality products made by world-famous brands. The system has a high automation and precision because computer control is used for the whole process. There are dynamic diagrams and easy man-machine conversation; all technical parameters can be modified on computer. Manpower is only needed for loading and unloading of glass. The control elements are the most famous parts. The stable and reliable system has large capacity for depositing product parameters to fit for the modern industry operation and management. Considerate design for lower installation power and energy saving. Broad applications: Low-E glass, coated glass, and all colors glass sheets. 1. Suitable Glass Sorts: Clear float glass (soda lime silicate glass) Surface coated glass, when suited for tempering (Including most kinds of hard coated glass and certain special soft-coated glass types, which can withstand about 700 ℃) Rolled patterned glass (when suitable for tempering) Body tinted glass Colored glass Enameled glass Reflection glass (when suitable for tempering)