Buffer Storage Web Tension Control via Residual Pressure
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Solution Overview
Problem
Existing roller or buffer stores for web-shaped flat materials face operational reliability issues, particularly when the material tears, leading to sudden movement of movable registers and potential injury risks due to maintained working pressure during disruptions or machine standstill.
Innovation Solution
A control valve arrangement that disconnects the cylinder chamber from the pressure source and locks the fluid volume, reducing pressure to a residual level (30-40% of working pressure) using a relief valve, ensuring minimal tension and preventing abrupt movements during faults or standstill.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cylinder chamber is connected to the pressure source during normal operation, then the web tension is maintained at working pressure levels, but during disruptions or machine standstill the full working pressure remains effective causing the movable roller register to move abruptly into the end position creating injury risk
Solution Approach 1:
The control valve arrangement automatically switches from the first state (full pressure) to the second state (residual pressure) before any disruption occurs or as soon as disruption is detected. This preliminary action of pressure reduction ensures that when material tearing or machine standstill happens, the dangerous full working pressure is already reduced to a safe residual level, preventing the abrupt movement of the movable roller register that causes injury risk
Solution Approach 2:
The system changes the pressure parameter from full working pressure to residual pressure (30-40% of working pressure) by switching the control valve arrangement between two states. This parameter change is automatically triggered during disruptions or machine standstill, transforming the hazardous high-pressure state into a safe low-pressure state that maintains minimal web tension while eliminating the injury risk from abrupt register movement
2Object-affected harmful factors
If the pressure in the cylinder chamber is reduced to residual pressure during standstill or malfunction, then the safety risk is reduced, but the web tension becomes minimal requiring precise pressure control to maintain proper material running
Solution Approach 1:
The relief valve is designed to open at a pressure above the residual pressure and block at a pressure equal to or smaller than the specified residual pressure. This feedback mechanism automatically adjusts the pressure to maintain the precise residual level needed - high enough to keep the web material running properly through the buffer store, but low enough to ensure safety. The system self-regulates without manual intervention, balancing safety and operational requirements
Solution Approach 2:
The control system automatically maintains the residual pressure in the cylinder chamber during standstill or malfunction without requiring external control. The relief valve self-regulates the pressure by opening when pressure exceeds the residual level and closing when it reaches the target level, thereby maintaining proper web tension for material running while ensuring safety. The system serves itself by automatically balancing the conflicting requirements of safety and material handling
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
Enhances operational reliability by reducing the risk of injury and maintaining material tension just enough for smooth operation, allowing for safe handling and reduced pressure-related hazards during material tears or machine stoppages.
Implementation Method 1
at least one element acting as a spring is provided for tensioning the flat material between the roll registers, which in known buffer stores is formed, among other things, by at least one piston-cylinder arrangement (pneumatic cylinder) with at least one cylinder chamber that is pressurized with the working pressure of a compressible fluid in the form of compressed air
Implementation Method 2
the pressure in the at least one cylinder chamber is reduced to a residual pressure that is well below the working pressure. The pressure is reduced to the residual pressure via a relief valve, which is preferably also switched with the first control valve arrangement and which is designed in such a way that it opens at a pressure above the residual pressure and causes the relief, for example by venting to the atmosphere
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a buffer storage for a flat web material (2), having at least two roller registers (3, 4) comprising a plurality of freely rotating rollers (11, 12) and displaceable relative to each other at least in one axis direction radial to the axis of the rollers (11, 12), for forming variable partial lengths or loops of the flat web material (2) between the rollers (11, 12) of the roller register, having at least one piston-cylinder arrangement (8), the cylinder chamber (10) thereof being able to be acted upon by a compressible pressure medium, such as compressed air, and acting like a pressure or gas spring between the at least two roller registers (3, 4) for generating a web tension of the flat material (2) guided through the buffer storage, and having a control device for applying a constant or substantially constant operating pressure of the pressure medium to the at least one piston cylinder arrangement (8).