Drafting Unit Apron Cage Negative Pressure Fiber Alignment
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Solution Overview
Problem
High rotational speeds in drafting systems of spinning machines lead to air flows that deflect and detach fibers from the sliver, negatively affecting yarn uniformity and quality.
Innovation Solution
A drafting unit with an apron cage subjected to negative pressure is placed between top rollers, using an air-permeable apron to apply suction air and guide fibers, ensuring they remain aligned and cohesive through the use of strategically positioned passage openings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the rotational speed of the output roller pair is increased to achieve higher productivity, then the production speed increases, but air flows are generated that deflect and detach fibers from the sliver, deteriorating yarn uniformity and quality
Solution Approach 1:
The patent converts the harmful air flows generated by roller rotation into a beneficial suction flow. By introducing a suction opening in the apron cage and applying negative pressure, the previously harmful drag flows and outgoing flows are transformed into a controlled suction flow that actively holds fibers in the sliver, preventing fiber deflection and detachment while maintaining high production speeds
Solution Approach 2:
The patent applies pneumatic principles by using negative pressure (suction) through the apron cage to control air flow and fiber behavior. The suction opening creates a controlled pneumatic field that counteracts the harmful air flows generated by roller rotation, using air pressure differential as the primary mechanism to maintain fiber cohesion in the sliver
2Productivity
If the rotational speed of the output roller pair is increased to improve productivity, then output increases, but fibers are deflected and detached from the sliver, reducing manufacturing precision
Solution Approach 1:
The harmful air flows that cause fiber deflection and detachment are converted into a beneficial suction flow through the apron cage. The suction opening creates a controlled negative pressure field that transforms the previously harmful drag flows into a fiber-holding force, maintaining sliver quality even at high production speeds
Solution Approach 2:
The suction flow is applied in advance to counteract the harmful air flows before they can cause significant fiber deflection or detachment. By creating the suction field through the apron cage ahead of the problematic gusset area, the system preemptively prevents fiber loss and maintains sliver integrity
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 arrangement effectively minimizes fiber deflection, enhancing sliver quality and yarn uniformity by maintaining fiber cohesion, particularly in the gusset area of the rollers, resulting in improved yarn quality.
Implementation Method 1
an apron cage (8) which can be subjected to negative pressure for the circumferential guidance of an air-permeable apron (10) together around the apron cage (8) and an apron top roller (6), which is formed by a third top roller (6) assigned to the apron cage (8)
Implementation Method 2
guidance of an air-permeable apron (10) together around the apron cage (8)
Data Source
Figure 1~2
Figure 3
AI summary
The present invention relates to a drafting unit (1) for a drafting unit (20) of a spinning machine. The drafting unit (1) has a first upper roll (2) and a second upper roll (4) spaced apart from it along a fiber strip transport direction (R), which are provided for drafting a fiber strip transported from the first (2) to the second upper roll (4) in conjunction with correspondingly assigned lower rolls (3, 5), wherein the respective axis of rotation of the first (2) and second upper roll (4) extends transversely to the fiber strip transport direction (R).The drafting unit (1) is characterized in that a belt cage (8), which can be pressurized with negative pressure, is arranged between the first upper roll (2) and the second upper roll (4) for the circular guidance of an air-permeable belt (10) together around the belt cage (8) and a belt upper roll (2, 6), wherein the belt upper roll (2, 6) is formed by the first upper roll (2) or a third upper roll (6) associated with the belt cage (8), which is arranged on the same side as the first (2) and second upper rolls (4) with respect to the fiber strip to be transported. The belt cage (8) has at least one passage opening (12), which can be pressurized with negative pressure, for pressurizing the fiber strip running between the first (2) and second upper rolls (4) via the air-permeable belt (10).