Suction Roll Asymmetric Air Inlet Zone Design
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Solution Overview
Problem
Suction rolls in fibre web machines experience energy inefficiency and uneven suction effects due to air flow disturbances, leading to increased energy consumption and noise levels.
Innovation Solution
The design features a rotatable roll shell with a suction box having an asymmetric air inlet zone and longer second seal extension, promoting a swirling air movement and reducing backflow, which is connected to a source of underpressure to maintain a consistent suction effect across the roll.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional suction roll with symmetric seal arrangement is used, then the structure is simple and easy to manufacture, but air flow disturbances occur causing uneven suction effect and high energy consumption
Solution Approach 1:
The patent applies asymmetry by positioning the air inlet zone asymmetrically between the two seals, specifically closer to the second seal in the direction of rotation. This asymmetric configuration optimizes the air flow pattern, reduces turbulence and backflow, thereby decreasing energy consumption while maintaining manufacturing simplicity through the basic seal and inlet zone arrangement.
2Device complexity
If a conventional suction roll with symmetric seal arrangement is used, then the structure is simple, but the suction effect varies over the axial length of the roll
Solution Approach 1:
The asymmetric positioning of the air inlet zone relative to the seals creates a more uniform air flow distribution across the axial length of the roll. This asymmetry compensates for the natural pressure gradient that develops during rotation, ensuring consistent suction effect from one end of the roll to the other without requiring complex additional components.
3Reliability
If higher vacuum pressure is applied to compensate for air flow disturbances, then sufficient suction effect is achieved over the entire roll length, but energy consumption increases
Solution Approach 1:
By positioning the air inlet zone asymmetrically closer to the second seal, the patent reduces air flow disturbances and backflow into the suction box. This allows the vacuum system to operate at lower pressure levels while maintaining consistent suction effect across the entire roll length, thereby reducing energy consumption of the stationary vacuum system.
Solution Approach 2:
The patent converts the naturally occurring pressure gradient during rotation from a harmful factor causing backflow into a beneficial feature. The asymmetric inlet zone positioning utilizes the pressure distribution to guide air flow more efficiently into the suction box, reducing the need for high vacuum pressure and lowering energy consumption.
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 design reduces energy consumption and noise while maintaining a consistent suction effect along the suction roll, as demonstrated by computer simulations showing reduced pressure differences and energy savings.
Implementation Method 1
The suction box is connected to a source of vacuum (underpressure) such that a suction effect is achieved
Data Source
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AI summary
The invention relates to a suction roll (1) having a rotatable roll shell (2) with a plurality of perforations (3); a suction box (4) within the rotatable shell (2) which has a wall that defines an inner space (5) that is connected to or connectable to a source (6) of underpressure. The suction box (4) has a circular cylindrical cross section and it is arranged to remain stationary while the roll shell (2) rotates. A first seal (7) and a second seal (8) arranged on the suction box (4) delimit a suction zone. The wall of the suction box (4) has an air inlet zone (9) formed by at least one through-hole (10), the air inlet zone (9) is located in the area between the first seal (7) and the second seal (8) such that a suction zone (11) is formed in the area between the seals (7, 8) when the suction box (4) is connected to a source (6) of underpressure. With regard to the seals (7, 8), the air inlet zone (9) is asymmetrically placed in the circumferential direction of the roll shell (2) in such a way that it is displaced towards the second seal (8).