Overview
Capacity & Length
Factors
When Customers Choose Drying Ovens, Major Specifications Most Concerned Are Production Capacity & Oven Length Which Depend On Various Factors.
Ink Drying Temperature & Time
Basically there are two types of ink, low and high temperature inks. Low temperature ink is required for those glass need no tempering. High temperature ink is required for those glass need to be tempered. Drying temperature for either ink could be from 120℃ to 180℃. This temperature determines drying time which could be from 5 ~ 6 minutes for high temperature ink to 10 ~ 16 minutes for low temperature ink. These durations determine how long glass stays or travels inside oven, which eventually determines glass travel speed. The higher the drying time, the longer the time glass stays in oven. The said data of drying temperature and time are applicable only for popular inks and paints. Special inks and paints may require drying temperature which falls out of the ranges.
Glass Travel Speed
Base on practical production experience for usual inks and paints, lowest possible glass travel speed inside drying oven is approximately 1.5 m/min. Speed slower than 1.5 m/min. would not dry the ink properly. When glass travels in or out of oven, part of glass is at inlet/outlet conveyor under room temperature while part of glass is inside oven under high temperature. If glass travels too slowly, there is a long time exposure under uneven temperature gradient across the glass. This may harm ink drying performance. The higher glass travel speed, the higher production throughput.
Glass Length
Oven width is determined by glass width. Glass could travel in short edge or long edge leading. Usually, glass travels in short edge leading for glass drying oven. So oven width is determined by glass short edge. Therefore, glass length of an oven usually refers to long edge. The shorter the glass length, the higher is production capacity.
Glass Space Distance
The shorter the glass space between one and another, the higher is oven efficiency. Production throughput is higher and oven is shorter.
Calculation
Assumptions / Formulas
| Items | Assumptions / Formulas |
| Drying Time | T |
| Glass Length | a |
| Glass Space Distance | c |
| Glass Travel Speed | s |
| Glass Travel Distance inside Oven (m) | b = s * t |
| Interval of Every Glass Exit Out of Oven (min.) | e = (a + c) / s |
| Nr. of Glass Exit Out of Oven per Minute (pcs/min.) | f = 1 / e |
| Production Capacity per Hour (pcs/hr) | P = f * 60 |
| Oven Length (m) | L = a + b |
| Nr. of Glass inside Oven (pcs) | x = (L + c) / (a + c) |
Production Capacity
| Examples | Glass Length (a) | Glass Travel Speed (s) | Glass Space Distance (c) | Interval of Every Glass Exit Out of Oven (e) | Nr. of Glass Exit Out of Oven per Minute (f) | Production Capacity (P) |
| AⅠ | 1 m | 2 m/min. | 0.3 m | 0.65 min. | 1.54 pcs | 92.4 pcs/hr |
| AⅡ | 2 m | 2 m/min. | 0.3 m | 1.15 min. | 0.87 pcs | 52.2 pcs/hr |
| AⅢ | 1.5 m | 3 m/min. | 0.3 m | 0.60 min. | 1.67 pcs | 100 pcs/hr |
| AⅣ | 1.5 m | 4 m/min. | 0.3 m | 0.45 min. | 2.22 pcs | 133.2 pcs/hr |
| AⅤ | 1.5 m | 2 m/min. | 0.3 m | 0.90 min. | 1.11 pcs | 66.6 pcs/hr |
Oven Length
| Examples | Glass Length (a) | Glass Travel Speed (s) | Drying Time (t) | Glass Travel Distance inside Oven (b) | Oven Length (L) |
| BⅠ | 1 m | 2 m/min. | 5 min. | 10 m | 11 m |
| BⅡ | 2 m | 2 m/min. | 5 min. | 10 m | 12 m |
| BⅢ | 1.5 m | 3 m/min. | 5 min. | 15 m | 15.5 m |
| BⅣ | 1.5 m | 4 m/min. | 5 min. | 20 m | 21.5 m |
| BⅤ | 1.5 m | 2 m/min. | 10 min. | 20 m | 21.5 m |
| BⅥ | 1.5 m | 2 m/min. | 15 min. | 30 m | 31.5 m |
Conclusion
| Examples | Glass Length (a) | Glass Space Distance (c) | Glass Travel Speed (s) | Drying Time (t) | Production Capacity (P) | Oven Length (L) |
| AⅠ + BⅠ | 1 m | 0.3 m | 2 m/min. | 5 min. | 92.4 pcs/hr | 11 m |
| AⅢ + BⅢ | 1.5 m | 0.3 m | 4 m/min. | 5 min. | 133.2 pcs/hr | 21.5 m |
| AⅤ + BⅤ | 1.5 m | 0.3 m | 2 m/min. | 10 min. | 66.6 pcs/hr | 21.5 m |
| AⅤ + BⅥ | 1.5 m | 0.3 m | 2 m/min. | 15 min. | 66.6 pcs/hr | 31.5 m |
From Examples AⅤ + BⅤ and AⅤ + BⅥ, it is noticed that oven length of BⅥ is 10m longer than BⅤ but their production capacities are identical 66.6 pcs/hr. This is due to different drying times, 10 min. Vs 15 min. Glass of BⅥ stays 5 minutes longer than BⅤ. Since glass always travels inside oven, oven must be longer so that glass can travel 5 minutes more.
