Web Suction Duct Layout to Prevent Fiber Clogging in Sheet Forming
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Solution Overview
Problem
Existing sheet manufacturing apparatuses experience high maintenance frequency due to clogging of suction ports from fibers adhering to through-holes, caused by humidified air used to moisten the web.
Innovation Solution
The apparatus includes a suction unit with a first duct, a second duct downstream of the first duct, and a third duct downstream of the second duct, featuring larger suction holes in the second duct to reduce fiber adhesion and clogging, along with a humidification unit that moistens the web from the opposite side to minimize adherence to the transport belt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If humidified air is supplied from the outlet of the humidification unit to moisten the web, then the web is successfully moistened, but fibers separate from the web and adhere to the through-holes of the suction port, causing clogging and requiring frequent maintenance
Solution Approach 1:
The suction unit is divided into multiple suction ports (first suction port facing the humidification unit outlet, second suction port facing away from it). This segmentation allows different regions to handle different functions: the first suction port handles web transport while the second suction port captures fibers before they can clog the first suction port's through-holes.
Solution Approach 2:
The second suction port acts as an intermediary that intercepts fibers separated from the web by humidified air. By providing this intermediate capture point, fibers are removed from the airflow before they can reach and clog the through-holes of the first suction port, thus protecting the main suction function.
2Force
If the suction unit uses through-holes to attract and attach the web to the transport belt, then the web is held securely for transport, but the through-holes become clogged with adhering fibers, reducing suction effectiveness
Solution Approach 1:
The suction function is segmented between two separate suction ports: the first suction port with through-holes provides suction force for web attachment, while the second suction port provides an alternative pathway that prevents fiber accumulation at the first suction port, maintaining its suction effectiveness.
Solution Approach 2:
The suction unit configuration is changed from a single suction port to multiple suction ports with different orientations. This parameter change in the suction system's structure allows simultaneous achievement of strong web attachment (through the first suction port's through-holes) and fiber removal (through the second suction port).
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 configuration reduces the frequency of maintenance by minimizing fiber adhesion to suction holes, thereby enhancing the apparatus's operational efficiency and reliability.
Implementation Method 1
the negative pressure generated by a suction unit. The suction unit sucks air through through-holes of a plurality of suction ports and through the transport belt and causes the web to be attracted and attached to the transport belt
Implementation Method 2
Moisture is added to the web by the humidified air supplied from an outlet of a humidification unit
Data Source
AI summary
A sheet manufacturing apparatus 1 includes: a deposition unit 50 that forms a web W; a transport belt 621 that comes into contact with an upper surface of the web W to hold the web W and transports the web W in a transport direction; a suction unit 200 that is provided above the transport belt 621 and causes the web W to be attracted and attached to the transport belt 621 by suction; a humidification unit 265 that faces the transport belt 621 and adds moisture to the web W from below; and a sheet forming unit 70 that presses the web W to form the web W into a belt-shaped sheet P1. The suction unit 200 includes a first duct 210, a second duct 220 provided downstream of the first duct 210, and a third duct 230 provided downstream of the second duct 220. The humidification unit 265 has an outlet 265a for discharging humidified air. The second duct 220 faces the outlet 265a. A plurality of first suction holes 219a and 219b for sucking air are provided in a suction region 213 of the first duct 210. A plurality of second suction holes 229 for sucking air are provided in a suction region 223 of the second duct 220. Diameters of the second suction holes 229 are larger than diameters of the first suction holes 219a and 219b.