GLASS TEMPERING FURNACES |
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Horizontal Roller Hearth Flat Glass Tempering Furnace |
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| 1. Description of the Equipment |
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| 1.1 Brief Introduction |
| The furnace includes loading table, heating section, flat quenching and cooling section, blast heads, unloading table, blowing & cooling system and control system. It is used to manufacture flat tempered glass for furniture, home appliance, architecture glass, etc. |
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| 1.2 Loading Table |
| he loading table is composed of rubber-covered rollers. When the glass is put onto the rollers, the glass will be conveyed automatically to the entrance of the furnace where it will be in ready-to-enter-furnace position and the rollers stop moving. It will send the glass into the furnace once the computer control system gives enter instruction. |
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| 1.3 Heating Section |
The structure of the heating section is of a double-layer box type covered with thermo-insulating material. Inside the section there is a conveyor system with high temperature resistant ceramic rollers, which are imported from well-known manufacturers, i.e. Vesuvius, France; Ceradyne, USA; etc. Heating elements and radiation plates are installed on the upper layer and lower layer of this section. The heating element is of an integrated part with spiral type resistance erected on ceramic part, it's easy to replace. When the glass is going to enter the furnace, the front door of the heating section opens, the rollers of the loading table and heating section move at the same time. When the glass is in the furnace, the front door will close and the glass on the rollers will be moved back and forth at the distance calculated by the controlling system automatically, so that the glass will be heated evenly. The upper section can be lifted up by remote control for maintenance. The heating elements are in matrix layout. The upper side has 48 heating elements, and lower side has 30 also. Each has one independent control loop.
The following heating thread arrangement is the furnace of size 2440(width)*3660(length): |
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1－1 |
2－1 |
3－1 |
4－1 |
5－1 |
6－1 |
1－2 |
2－2 |
3－2 |
4－2 |
5－2 |
6－2 |
1－3 |
2－3 |
3－3 |
4－3 |
5－3 |
6－3 |
1－4 |
2－4 |
3－4 |
4－4 |
5－4 |
6－4 |
1－5 |
2－5 |
3－4 |
4－5 |
5－5 |
6－5 |
1 area |
2 area |
3 area |
4 area |
5 area |
6 area |
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| 1.4 Flat Quenching/Cooling Section |
| The blast heads are divided into upper and lower parts. The nozzles are made of aluminum alloy, and the distance between glass and upper/lower nozzles can be adjusted according to the quenching demand for different kinds of glass. In among the blast heads, there are a lot of rollers conveying the glass sheets forwarding. When the glass sheets comes out the furnace, the rollers here will move synchronously with the rollers in the furnace, to transit the glass sheet into quenching section. Meanwhile, the huge blower will immediately blow the high pressure air on the surface of the glass through air ducts. The air pressure and flux is decided by the openness of the butterfly valve at the inlet of blower, which is controlled automatically by the control system. And the rollers are covered by one kind of special heat-resistant material. |
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| 1.5 Unloading Table |
| The unloading table is the same as the loading table. When the glass is transported to the end of the conveyor, the rollers will stop, and the glass can be taken away by hand, or by robot, if there is available at the customer’s factory. |
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| 1.6 Control System |
| The control system includes the followings: |
| Process parameters storage and re-call, such as glass thickness, size, color, glass type and maybe different sources of float glass and etc. Whenever you produce a new order for different thickness, size, color, type, source and etc., you just enter the process parameters, and the system will memorize these process data. Next time, when you have the re-order, or the same order, you can re-call the data, and the machine will automatically use the stored processing data to produce. |
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- Controller for roller driving system.
- Controller for the temperature control.
- Controller for quenching control.
- The abnormity alarming system would warn while trouble happens to indicate how to solve this trouble.
- The furnace has auto pre-heating function. After the shift of a day, the furnace will be in the stand-by status, only less than 25% of heating power will be consumed, while the ceramic rollers will be still running. And ahead of working time on the next morning, the system will start up to heat up to the working temperature until the operator begins the production.
- The main industrial control computer is installed with the terminals at the control desk. Display screen can provide users with analog process status: main screen, process parameter screen, operation and maintenance screen and system parameter screen. The system has reading and writing function for process parameters, automatic control, unit equipment operation and test as well as self-diagnosis, as well as display alarming function.
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| a) Main drive control system is accomplished by the inverter system which is controlled by computer. On-line of every part is controlled by computer. |
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b) The main screen is the page displayed on the monitor during normal production. The contents displayed directly in English are the statuses of glass in the furnace, driving system, temperature at each zone, time of heating, quench and cooling, actual pressure, set point of fans and length sum of pieces of glass in the furnace. This screen is for the operator's notice. The process parameter screen records the designed moving distance of loading table when the pedal switch is actuated by the operator, temperature set point of upper and lower furnace, pressure set point of fans, quench time and cooling time set point. These screens are frequently used for normal operation. Maintenance screen is used by maintenance people to test every part of the system. System parameter screen is used by the manufacturer, in order to test the machine. |
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| 2. Technical Features |
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| 2.1 Technical Specifications |
- Glass thickness range : 4 - 19 mm
- Glass size:
Max glass size: 2,440 (width) x 3,660 mm (5-19mm)
2,440 (width) x 1,770mm (4mm)
Min glass size: 100 x 300 mm
- Standard: ANSIZ-97.1
- Finished product rate: 4mm not less than 95%;
over 5mm not less than 97%.
- Productivity / Process cycle time: 18 Loads per hour for 5 mm (max.)
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| 2.2. Utilities |
| 2.2.1 Installed power: |
Heating: 530 kW
Drives: 20 kW
Quenching: 220 KW
Total installed power: 770kW x 80%= 616KW |
| 2.2.2 Compressed air (One air tank should be supplied with 0.5M3 at least by the Buyer ) : |
Volume: 0.6 - 0.8 m3 /min
Pressure: > 0.7 MPa |
| 2.2.3 Suitable glass sorts: |
- Clear float glass
- Coated glasses (Including most kinds of hard coated glass, parts of special soft coated glass, which withstands about temperature 700 ℃)
- Patterned glass
- Tinted glass
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| 2.3. Supply Scope |
-- Loading Table
-- Heating Section (Furnace)
-- Flat Quenching / Cooling Section
-- Unloading Table
-- Associated Electrical and Control Equipment
-- Blower System
-- Control Terminal |
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| 2.4 Controlling System |
1) The whole control procedure, software of industrial computer and PLC are whole one special module is developed by one industrial control company
2) PLC is OMRON product.
3) Industrial computer is one product from Taiwan.
4) Inverters are original France products or equivalent ones.
5) Optical, Sensor Beam Switch is of OMRON product.
6) Monitor is from PHILIPS |
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