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Industrial Applications of Induction Heating
Published in Valery Rudnev, Don Loveless, Raymond L. Cook, Handbook of Induction Heating, 2017
Valery Rudnev, Don Loveless, Raymond L. Cook
With induction annealing of copper alloys, the major savings over the roller hearth furnace occurs where the second layer winding operation is eliminated [34,35]. This not only saves the cost of the equipment purchase of a second layer winding machine but also reduces operating costs and provides a higher production rate. Modern induction ACR copper tube annealers can process tubes at a speed up to 600 m/min (10 m/s). The exposure to mechanical damage of fully annealed product handling is also eliminated.
An energy-efficient vacuum system as an alternative to the inefficient use of compressed air for the yarn suction gun
Published in The Journal of The Textile Institute, 2023
Jurij Prezelj, Tadej Novaković, Luka Čurović, Anže Železnik, Jure Murovec
The air suction gun for yarn manipulation is an integral part of the yarn production system based on melt-spinning extrusion combined with a high-speed winding machine. It is used to manipulate a running yarn at the beginning of the winding process to thread it through guide elements that supply the yarn to a spinning bobbin. Compressed air is usually used as the energy source to drive the yarn suction gun (YSG) and as a supporting transport medium (Li et al., 2014). An air suction gun is a type of fluid machine that draws one or more running yarns by both an injection mechanism and the friction of a high-speed air jet. The main requirements of an air suction gun are (1) strong suction of the yarn, (2) low compressed air consumption, (3) compact size, (4) low noise, etc. (Li et al., 2010b). Strong suction can be described by two parameters: the velocity of air flow in the suction tube and the tension force. In our case, the velocity of the air flow must be high enough to transport the waste yarn from the extruder to the waste compartment with a suction velocity of more than 100 m/s. The term tension is inappropriate because it expresses the effect of force per unit area. Therefore, a better term would be axial yarn force, expressed in any unit of force. However, both in the literature and in practice, axial yarn force is usually referred to as yarn tension (Chattopadhyay & Venugopa, 2020). Chattopadhyay et al. performed the measurement of tension in polyester filament yarn (PFY) ( = 1854 kg/m3, = 4.4768 × 10−9 m2, = 3.575 × 10−4 N/m2, = 0.1, = 3.943 × 10−3 Ns/m2) during the winding process in real time. The tension force measurement was based on the natural frequency of the yarn. Based on the results of Zhang et al., tension was estimated to be 25 cN at a winding velocity of 4.17 m/s and 45 cN at 7.5 m/s (Zhang et al., 2022). The tension force generated by the YSG must be high enough to allow cutting of the yarn at the beginning of the winding process, preferably above 20 cN per single yarn. The consumption of compressed air should be as low as possible, but to achieve adequate velocity in the suction tube with sufficient force, the adiabatic power delivered to the YSG can easily exceed 50 kW. Considering a typical overall efficiency of compressed air generation, treatment, and delivery, the electrical power requirement increases to over 75 kW for the operation of a single YSG.