GLASS TEMPERING FURNACES |
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Double Direction Flat/Bend Glass Tempering Furnace |
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| 1. Description of the Equipment |
| AWPF Double Direction Flat/bend Glass Tempering Furnace composed of loading (unloading) section, bend cooling section with soft roller, heating section, bent cooling section with hard roller, flat tempering and cooling section, unloading (loading) section, blower system and control system. Flat and bend cooling section installed at different end of the heating section and work in double directions. |
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| 1.1 Loading (unloading) section |
| The loading section includes rubber-coated rollers, loading drive motor, photoelectric switch, supporting frame, side loading rubber coated rollers, etc.. The rubber-coated rollers are driven by chains, transporting the placed glass to the photoelectric switch before the front door of the heating section, ready to enter the furnace. The drive motor for loading is driven by AC inverter. During loading, the motor drives the rubber coated rollers running at slow speed. When glass is entering the furnace, the transmission motor drives the rubber coated rollers running at high speed. The photoelectric switch will measure and record the length of each and total glass entering the furnace. Supporting frame and side loading rollers are used for loading larger glass. |
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| 1.2 Bend Cooling Section with soft roller |
The forming method is automatic quench transmutation. It needn’t any mold. The bending forming section includes upper and lower transmutation mechanism, upper and lower quenches, quench lifting mechanism, glass conveying rollers, etc. The glass conveying rollers are soft shaft aluminum-alloy wheel with fiber rope, which assure a long service life.
The cooling quenches for bent section are separated structure and fixed among the shafts and deform with them. The cooling air is blown in from the grid back through heat resistant soft hose. |
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| 1.3 Heating section |
The heating section includes the roof lifting mechanism, heating system, air balance system, ceramic rollers, driving system, emergency cooling system, the glass length and temperature measuring devices.
The heating furnace is divided into upper and lower parts. The upper furnace can freely move up and down by the roof lifting mechanism for easy maintenance. The roof lifting mechanism is composed of set of screws, bevel gear, reduction device, motor, upper and lower limit switches and safety protection devices.
The upper and lower parts of the furnace are heated independently in each heating zone. Each heating zone has its thermocouple forming an independent control loop.
Advanced matrix “talent control” process is unique and special designed for temperature control system, which ensure the precision and even/balance of temperature control to best state and situation.
For the temperature measurement we adopt the most advanced and latest “modularization” central collection process, which highly improve the precision and good reliability of temperature measurement, as well decrease 80% failure rate if comparing with the normal measurement method.
Inside of heating oven, there will be installed a compress air balance system. Comparing with the normal radiation heating way, we have changed this kind of single heating way to two modes: radiation heating and convection heating, which not only can ensure the much more homogeneous temperature, top quality of finished glass flatness, but also quite suitable for more kinds of coated glass and heat reflective glass tempering.
The ceramic rollers system is driven by round belt. Each ceramic roller is separately moved by individual belt, but all the belts are conveyed by same one set of transmission system, which can ensure simultaneous and stable running, and avoid the scratch and destroy of glass when above the rollers.
When the glass is entering the furnace, drive motors will make the rollers in the loading section and ceramic rollers simultaneously running, conveying the glass into the heating furnace.
When the glass is heated, the main drive motor (namely ceramic roller transmission) will make the ceramic rollers do reciprocating movement, air convection system start to work, so that the glass can be heated evenly.
When the glass is exiting the furnace, the rollers in the forming section and the heating section run simultaneously, conveying the glass to flat or bend tempering and cooling section.
The emergency cooling system on top of the furnace is used to cool down the oven quickly by the control button in operation panel when necessary, such as some failure occurs in heating oven, or maintains state. |
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| 1.4 Bent cooling section with hard roller: |
The forming method is automatic quench transmutation. It needn’t any mold. The bending forming section includes upper and lower transmutation mechanism, glass conveying and oscillating device, upper and lower quenches, quench lifting mechanism, glass conveying rollers, and press roller etc. The glass conveying rollers are steel rollers with fiber rope, which assure a long service life. The press roller is hard roller with fiber rope too, it can make the curve of the finial bent glass smooth.
The cooling wind-grids (quench) for bent tempering are separated structure and fixed among the rollers and deform with them. The cooling air is blown in from the grid back through heat resistant air-pipes. |
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| 1.5 Flat Tempering and Cooling Section |
| The tempering and cooling section includes transmission rollers, the upper and lower quenches, quench open/close mechanism, upper quench up & down mechanism and air hose. Entwined around transmission rollers are special fiber which can endure high temperature. The heated glasses are conveyed by conveying rollers to cooling section to cool. The rollers are driven by chain and the inverter can insure the same speed of different section. The quench is of separated ladder-type combination structure. The upper quench up & down mechanism can adjust the height of the upper quench very easily. The upper and lower quenches will automatically close during cooling and open after cooling. When the glass begin to exit from the oven cooling air blow out from holes of the quench. The glass move back and forth on the rollers until it is cool down. To produce different thickness glass, computer will adjust the air door of blower, valve or the blower inverter, in order to set the relevant air pressure and air volume. After that, the rollers convey the tempered flat glass to unloading section |
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| 1.6 Unloading section |
| It’s primarily the same as the loading section. After cooling, the glasses are conveyed to this section. The glass stop automatically when reach the end, then the operators unload them by hands. |
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| 1.7 Blower system |
| The blower system includes the blowers, control cabinets (or blower inverter), air valve for flat tempering, air collector, air adjusting devices for upper and lower quench and air channel. This system is used to supply cooling air to quench. The use of air collector is to guarantee homogeneous air pressure in every part of the quench. The air volume in the upper quench and lower quench can be automatically adjusted according to the products quality, making the quality of tempered glass optimum. When use inverter the blower can work in different speed according to technical requirement: when temper thick glass the blower run at lower speed, after the glass has tempered the blower run at high speed to cool the glass more quickly. If the glass is thin then use high speed at the beginning to get needed air pressure and lower the speed after that. This can save energy. |
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| 1.8 Control system |
The control system consists of temperature control system, transmission control system, air supply control system and alarm system during urgent trouble.
Advantech industrial control computer is chosen as main computer. Display screen is 17 inches colorful screen. Display screen, keyboard and mouse are put on operation table. Mainframe is installed in electric cabinet. Manual operation interface is consisted of working main page layout, technical parameter setting page layout, temperature fine-adjusting page layout, automatic temperature rising page layout and examining and repairing operation page layout.
On working main page layout, simulation drawing of the line and every technical parameters (such as temperature of each spot in heating furnace, heating time, blowing time, urgent cooling air pressure, cooling air pressure, speed of entering the furnace, swing speed and quenches height and etc.) can be completely displayed, fine-adjusted and amended.
Technical parameter setting page layout: In this page layout set the relevant technical parameters (such as temperature of each spot in heating furnace, heating time, blowing time, urgent cooling air pressure, cooling air pressure, speed of entering the furnace, swing speed and quenches height) according to glass thickness, color, kind and glass plant. It can be saved into data-base in type of file for conveniently using.
Automatic temperature rising page layout: In this page layout computer system will automatically raise temperature up to the required value only if setting well heating time and temperature.
Examining and repairing operation page layout: In this page layout operator can conveniently examine whether each input and output spots of the control system are normally running, which heightens the examining speed greatly.
PLC of Omron company is chosen for the assistant computer. Periphery elements (including electrical measuring element, executor and pneumatic measuring element and executor) are high quality product from importation and joint venture company. Hardware is reasonably compounded and techniques are advanced. System control software has features of powerful function and reliable running. Comfortable man-machine dialogue is conveniently for operators to handle. Test page layout of input and output is conveniently for machine maintenance and commissioning. The function of testing and recording trouble supply complete evidence for operators. |
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| 2. Technical features |
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| 3 Technical Qualification： |
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