Preheating Roll Drive with Adjustable Pulleys
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Solution Overview
Problem
Existing preheating roll assemblies for film production require frequent and costly adjustments of belt pulleys to accommodate changing process parameters, leading to excessive stress or slackening of the film, as they can only support one heating profile.
Innovation Solution
Implementing individual drives with asynchronous motors for each intermediate roll, controlled by a common frequency converter, allowing for adjustable rotational speed and torque to compensate for friction and film elongation, eliminating the need for pulley replacements and separate motors for each roll.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a common motor drives all preheating rolls via belts with fixed pulley diameters, then the structure is simple and cost-effective, but the heating profile cannot be adjusted for different process parameters
Solution Approach 1:
The patent applies dynamics by making the pulley diameters variable instead of fixed. Each preheating roll is equipped with a pulley whose diameter can be continuously adjusted within a range, allowing the heating profile to be adapted to different process parameters. This dynamic adjustment capability resolves the contradiction between adaptability and device complexity.
Solution Approach 2:
The invention changes the parameter of pulley diameter from a fixed value to a variable parameter that can be adjusted within a specific range. This parameter change enables the same drive system to accommodate multiple heating profiles and process conditions, achieving adaptability without proportionally increasing device complexity.
2Adaptability or versatility
If belt pulleys are replaced to change graduation for different process parameters, then the heating profile can be adjusted, but the expenditure and downtime are very high
Solution Approach 1:
By implementing dynamically adjustable pulley diameters, the system eliminates the need to physically replace pulleys when process parameters change. The pulleys can be adjusted in situ within a range, significantly reducing adjustment downtime and eliminating the costs associated with manufacturing and installing new pulleys.
Solution Approach 2:
The adjustable pulley mechanism allows operators to pre-set appropriate pulley diameters for different process conditions without stopping the production line for extended periods. This preliminary adjustment capability reduces both time loss and operational disruption.
3Ease of operation
If individual drives with separate motors and converters are assigned to each preheating roll, then rotational speed can be precisely adjusted, but the device complexity and adjustment labor increase significantly
Solution Approach 1:
The patent applies segmentation by dividing the control function: a single converter controls multiple asynchronous motors, while each motor drives one preheating roll with an adjustable pulley. This segmented approach maintains precise speed adjustment capability for each roll while reducing the overall number of converters and simplifying the control system architecture.
Solution Approach 2:
The single converter serves multiple motors simultaneously, making it a universal control unit for the entire preheating roll assembly. This multi-functionality reduces device complexity while maintaining the ability to independently adjust each roll's rotational speed through the combination of converter control and variable pulley diameters.
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
Enables reliable and easy adjustment to different process parameters, reducing labor and costs by maintaining consistent film tension and minimizing elongation effects, ensuring uniform rolling and efficient film production.
Implementation Method 1
Each asynchronous motor controls the surface speed and the torque of an intermediate roll
Implementation Method 2
the friction of the preheating rolls and elongation of the film are compensated in the preheating roll assembly
Data Source
AI summary
A device drives a preheating roll assembly comprising several rolls, during a heating or preheating stage. A motor assembly includes at least one individual drive and preferably two individual drives, which are used to drive at least the exit roll and preferably the entry roll and the exit roll. The motor assembly also includes one or more asynchronous motors, each asynchronous motor controlling the surface speed and the torque of one of the intermediate rolls. A common frequency converter operates one or more asynchronous motors, in particular all asynchronous motors.