Pressure-Controlled Drainage Strip for Precise Dewatering Angle
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Solution Overview
Problem
Existing drainage bars in paper machines struggle with precise adjustment of the angle between the drainage strip and the screen belt, leading to challenges in controlling dewatering and fiber orientation due to interaction with the screen belt.
Innovation Solution
A drainage strip with a deformable wall and adjustable pressure chambers, equipped with sensors for precise measurement and control of the wall's position and deformation, allowing for precise adjustment of the angle and gap between the drainage strip and screen belt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the drainage strip angle is adjusted by pressure changes in the chamber, then the angle between the drainage strip and screen belt can be changed, but the exact position of the surface is difficult to set due to interaction with the screen belt
Solution Approach 1:
A sensor is integrated into the chamber to detect the actual position of the drainage strip surface relative to the screen belt. This feedback signal is sent to a control unit that adjusts the pressure in the chamber to achieve the desired position, compensating for interactions with the screen belt and enabling precise positioning.
Solution Approach 2:
The manual or purely mechanical pressure adjustment system is replaced with an automated control system that uses sensor feedback to regulate pressure. This substitution of mechanical adjustment with an automated sensing and control system enables precise position determination despite screen belt interactions.
2Adaptability or versatility
If the wall position is changed by pressure changes, then the angle and gap between drainage strip and screen belt are adjustable, but control precision is insufficient
Solution Approach 1:
The sensor measures the actual gap between the drainage strip surface and the screen belt, providing feedback to the control unit. The control unit adjusts the chamber pressure based on this feedback to achieve and maintain the target gap position with high precision.
Solution Approach 2:
The system uses its own sensor feedback to automatically adjust and maintain the optimal gap position without external intervention. The control unit continuously monitors and adjusts pressure to keep the gap at the desired setpoint, enabling self-regulating precision control.
3Force
If the drainage strip surface forms an acute angle with the belt, then suction force can be exerted, but the suction force depends on the angle which is difficult to control precisely
Solution Approach 1:
The sensor provides real-time feedback on the drainage strip angle relative to the screen belt. The control unit uses this information to adjust the chamber pressure and maintain the optimal acute angle for maximum suction force, making angle control precise and easy to operate.
Solution Approach 2:
The system dynamically changes the pressure parameter in the chamber to control the drainage strip angle. By adjusting pressure, the angle can be precisely controlled to optimize suction force while the sensor ensures the angle remains at the desired value despite variations in screen belt tension or speed.
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 better control of paper web dewatering and fiber orientation by precisely adjusting the angle and gap, enhancing turbulence in the fiber suspension and improving the dewatering process.
Implementation Method 1
the wall facing the wire belt of the paper machine is deformable by pressure changes in the chamber in order to change the angle between the wall and the wire belt
Implementation Method 2
the position of the wall, and thus the surface facing the paper machine's wire belt, is changed by altering the pressure in the chamber
Data Source
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AI summary
A dewatering bar (1) of a paper machine has a base body (5) with a longitudinal direction oriented transversely to the direction of movement (4) of a wire belt (3). The base body (5) has at least one pressure-tight closed chamber (7) extending in the longitudinal direction (2) of the dewatering bar (1), wherein the chamber (7) has a connection to a pressure line (8), a wall (11) with a surface (12) facing the wire belt (3) of the paper machine, and side walls (13, 14) connected to the wall (11). The position of the wall (11) of the chamber (7) is variable, and a device (17) for detecting the change in position of the wall (11) due to changes in pressure is arranged in the chamber (7).