Heating Guide Roll Drying System for Coated Substrates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional drying ovens in gravure printing, dry laminating, and coating machines require extended drying times and slower production speeds due to the high evaporation latent heat of water-based coatings, leading to inefficiencies and potential substrate deformation.
Innovation Solution
Implementing a drying method where guide rolls in the drying oven are heated to raise the substrate temperature to the boiling point of the solvent quickly, followed by cooling rolls to prevent deformation, allowing for efficient drying without slowing production speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If hot air is blown toward the liquid agent-applied side to dry the coating, then the solvent evaporates, but the drying time becomes excessively long due to the small heat capacity of hot air and high evaporation latent heat
Solution Approach 1:
The patent introduces a transfer roll as an intermediary heat transfer medium. The transfer roll absorbs heat from the hot air and directly contacts the substrate, enabling efficient heat transfer to the liquid agent. This mediator overcomes the limitation of hot air's small heat capacity by using a solid medium with higher heat capacity and better thermal contact.
Solution Approach 2:
The patent replaces the purely convective heating method (hot air blowing) with a combination of conductive heating (transfer roll contact) and convective heating. The mechanical contact through the transfer roll provides direct thermal conduction, which is more efficient than convective heat transfer alone.
2Productivity
If the substrate temperature is raised quickly to the boiling point of the solvent for rapid drying, then production speed is maintained, but the substrate may deform due to excessive temperature
Solution Approach 1:
The patent applies local quality by using the transfer roll to provide concentrated heat exactly where needed (at the liquid agent-substrate interface) while the rest of the substrate remains at lower temperature. This localized heating enables rapid solvent evaporation without causing overall substrate deformation.
Solution Approach 2:
The patent changes the temperature distribution parameter from uniform heating to localized heating. The transfer roll creates a high temperature zone at the contact point with the substrate, while other areas remain cooler, allowing rapid drying without excessive overall temperature that would cause deformation.
3Use of energy by stationary object
If a long drying zone is provided to supply sufficient heat for drying, then the necessary heat quantity is achieved, but the drying oven becomes long and production efficiency decreases
Solution Approach 1:
The patent replaces the extended convective heating zone with a compact conductive heating system using the transfer roll. The mechanical contact and thermal conduction through the roll provide intense heat transfer in a short distance, eliminating the need for a long drying zone while still supplying sufficient heat energy.
Solution Approach 2:
The transfer roll acts as an intermediary that concentrates and delivers heat energy efficiently to the substrate in a compact space. This mediator enables high heat transfer density, allowing sufficient heat supply without requiring a long drying zone, thus reducing the overall length of the drying oven.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables rapid drying of both aqueous and oily coatings within a compact drying zone, maintaining production speed while preventing substrate deformation by efficiently managing heat transfer and temperature control.
Implementation Method 1
former portion of the plurality of guide rolls is made into heating guide rolls, and remaining latter portion is made into cooling guide rolls, thereby the introduced substrate is heated by the heating guide rolls
Implementation Method 2
thereafter, the substrate is cooled by the cooling guide rolls so as to keep a temperature where the substrate is not deformed
Implementation Method 3
evaporating the solvent in a drying oven to solidify the ink alone on the substrate
Implementation Method 4
it is necessary to dry it with compensating evaporation latent heat, by elevating the temperature of the liquid agent to evaporate the solvent
Data Source
AI summary
In an oven used for printing machine and the like, drying is rendered possible to be conducted without decreasing traveling speed (120 m/min or more) by a short and compact drying zone for a coating liquid agent which is made aqueous as well as oily coating liquid agent. A plurality of hot air blow-off nozzles 222 are provided in the drying portion 220 of the first printing unit 200. Heating guide rolls 223a are provided at the former portion, and cooling guide rolls 223b are provided at the latter portion, so that they meet the hot air blow-off nozzles 222. Liquid delivery pipes 224a for injecting hot water are connected to the heating guide rolls 223a, and liquid delivery pipes 224b for injecting cooling water are connected to the cooling guide rolls 223b. Introduced raw web 1 is heated to the boiling point of solvent or higher than that by the heating guide rolls 223a.