Air-Jet Spinning Unit With Nonlinear Piecing Acceleration
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Solution Overview
Problem
Existing air-jet spinning machines experience thread defects and breaks during the spinning process, leading to poor thread quality and component stress due to sudden acceleration of the drafting system and take-off device during the piecing process.
Innovation Solution
A non-linear speed increase of the output roller pair and take-off device is implemented, along with a controlled residence time in the vortex chamber, to moderate fiber introduction and reduce component stress, ensuring high thread quality and extended component life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drafting system and take-off device are accelerated linearly to the take-off speed during the piecing process, then the spinning process can be restarted quickly, but this causes high material stress and sudden increase in fiber mass in the vortex chamber leading to fiber distortion or build-up and poor thread bonding
Solution Approach 1:
The patent applies parameter changes by transitioning from linear acceleration to non-linear acceleration profiles. The acceleration parameter is modified to increase gradually at the beginning of the piecing process and only reach higher values near the end, preventing sudden fiber mass increase while still achieving quick process restart
Solution Approach 2:
The patent implements periodic action through a multi-phase acceleration process. The acceleration occurs in stages: initially slow to allow fiber sliver to feed gently into the vortex chamber, then progressively faster, and finally reaching full speed. This periodic variation in acceleration rate prevents fiber distortion while maintaining productivity
2Loss of time
If the drafting system and take-off device are accelerated quickly to the take-off speed during the piecing process, then the piecing process can be completed faster, but this results in high material stress on the components
Solution Approach 1:
The patent changes the acceleration parameter from constant (linear) to variable (non-linear). By controlling the acceleration profile to start slowly and increase progressively, the system completes the piecing process efficiently while avoiding excessive stress on drafting rollers and take-off device, thereby extending component life
Solution Approach 2:
The patent applies beforehand cushioning by introducing a controlled dwell time at the beginning of the piecing process where the drafting system starts first without immediate full acceleration. This cushioning period allows the system to prepare for the upcoming acceleration phase, reducing shock loads on components
3Reliability
If the drafting system is started before the take-off device during the piecing process, then a dwell time is created for the yarn end in the vortex chamber allowing proper connection, but this extends the total piecing time
Solution Approach 1:
The patent applies preliminary action by starting the drafting system before the take-off device during the piecing process. This creates a controlled dwell time that allows the fiber sliver to be properly positioned and connected to the yarn end in the vortex chamber before the take-off device begins operation, ensuring reliable thread bonding
Solution Approach 2:
The patent uses periodic action by implementing a multi-stage start-up sequence with a controlled dwell period. The drafting system operates at low speed initially to establish proper fiber connection, then both systems are accelerated together in a coordinated manner, minimizing total time while ensuring connection quality
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
The non-linear speed increase and controlled residence time in the vortex chamber result in improved thread quality and extended component life by avoiding sudden accelerations and fiber distortion, facilitating a reliable piecing process.
Implementation Method 1
a vortex-forming device for generating a vortex flow in a swirl chamber
Implementation Method 2
a drafting system for drawing and feeding a fibre sliver to the vortex chamber
Data Source
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AI summary
The invention relates to a spinning station of an air-jet spinning machine for producing a thread from a fiber sliver and to a method for carrying out a starting spinning process at such a spinning station, wherein a thread end wound onto a take-up bobbin is picked up by means of a thread receiving device and transferred to a thread end preparation device located downstream in the thread path direction of a vortex chamber of the air-jet spinning device, the thread end is then treated in the thread end preparation device and subsequently transferred to the vortex chamber of the air-jet spinning device and positioned there, and a drawing unit for drawing and feeding a fiber sliver into the vortex chamber is raised.wherein an output roller pair of the drafting unit is accelerated to a predetermined take-up speed, and wherein the fiber sliver is spun onto the prepared yarn end in the vortex chamber, and a motor-driven take-up device for drawing off the yarn spun in the vortex chamber is accelerated to the take-up speed. To provide a method for carrying out a starting spinning process and an air spinning machine that enables a reliable starting spinning process, it is provided that the drafting unit and/or the take-up device are accelerated in such a way that the speed of the output roller pair and/or the take-up device increases non-linearly at the beginning of the acceleration and/or approaches the predetermined take-up speed non-linearly in the region of the end of the acceleration.