Redundant Encoder Speed Measurement for Paper Machine Reliability
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Solution Overview
Problem
Winding devices in paper machines face operational reliability issues due to the failure of laser-based sensors used for determining the rotational speed of paper rolls, which can lead to machine failures if not cleaned promptly.
Innovation Solution
Replacing the laser-based sensor with an encoder or using a frequency converter to determine the rotational speed, allowing for redundant speed measurements to ensure continuous operation and prevent failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a laser-based sensor is used to determine the rotational speed of the paper roll, then the speed measurement can be obtained, but the sensor requires regular cleaning and may fail if not cleaned in time
Solution Approach 1:
The patent uses encoders (first encoder and second encoder) as alternative sensing mechanisms to the laser-based sensor. These encoders provide redundant speed measurement capabilities, allowing the system to continue operating even if one encoder fails, thereby improving reliability without sacrificing measurement precision
Solution Approach 2:
The patent changes the measurement principle from optical (laser-based) to electromagnetic (encoder-based). This parameter change in the sensing mechanism eliminates the cleaning requirement while maintaining the ability to accurately determine rotational speed and prevent web breaks
2Reliability
If a single encoder is used to determine rotational speed, then the system is simpler, but the operational reliability is reduced
Solution Approach 1:
The patent divides the speed measurement function into two separate encoders, each independently measuring the rotational speed. This segmentation allows the system to tolerate the failure of one encoder while maintaining operational reliability through the other encoder
Solution Approach 2:
The patent implements redundant encoders as a preventive measure against future failures. By having backup sensing capability in place before any failure occurs, the system can continue operating without interruption, cushioning against the potential harm of sensor failure
3Productivity
If the laser-based sensor is not cleaned regularly, then maintenance time is reduced, but the sensor may fail causing machine failure
Solution Approach 1:
The patent replaces the optical laser-based sensor with electromagnetic encoders that have no moving parts or optical components requiring cleaning. This substitution eliminates the maintenance requirement while ensuring continuous reliable operation, thereby improving both productivity and reliability
Data Source
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AI summary
The invention relates to a method and a system. The method serves to ensure particularly reliable operation of the system. According to the method, a first rotational speed (D1) and a second rotational speed (D2) are determined. Using the first rotational speed (D1) and/or the second rotational speed (D2), a speed (V1, V2) of a web (1) is determined. The first rotational speed (D1) is determined using a first sensor (9a). The second rotational speed (D2) is determined using a second sensor (9b) and/or a rotational speed measurement device (7F), in particular as part of a frequency converter (7). Due to the multiple determination of the rotational speed (D1, D2) or the speed (V1, V2) of the web (1), the system exhibits a high degree of operational reliability. Application areas of the invention include, in particular, a paper machine, a printing press, a tubular bag machine, or a winding device.