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Design and performance analysis of a self‐regulating melt pressure valve
Author(s) -
Kazmer David,
Gupta Dheeraj,
Munavalli Mahesh,
Kudchadkar Vijay,
Nageri Ranjan
Publication year - 2006
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.20399
Subject(s) - controllability , materials science , globe valve , consistency (knowledge bases) , extrusion , flow (mathematics) , molding (decorative) , flow control valve , control valves , flow control (data) , observability , shear (geology) , mechanical engineering , mechanics , control theory (sociology) , composite material , computer science , engineering , control (management) , mathematics , computer network , physics , artificial intelligence
Net shape manufacturing of plastic products through injection molding, extrusion, and other polymer processing methods has been limited by a lack of observability and controllability of the state of the polymer melt. A self‐regulating valve is developed and validated that regulates the output melt pressure in proportion to an input control force. The valve relies on a valve pin that adjusts the juncture loss to balance the control force with the force exerted by the melt pressure on an exposed surface of the valve pin. Since the valve pin position is adjusted in accordance to natural laws, an open loop system design is feasible without need of any instrumentation or control system for closed loop feedback control. The design is analyzed using a three‐dimensional flow analysis that utilizes independent shear and elongational viscosities for the polymer melt. Pressure drops and shear stresses through the valve are analyzed to estimate the steady state error in the output pressure when the valve pin is controlled in an open loop mode (i.e. without melt pressure feedback). Guidelines for the valve design are provided to achieve a reasonable trade‐off between flow and structural requirements. Finally, experimental validation indicates an excellent level of response and consistency given the simplicity of the design. POLYM. ENG. SCI. 46:549–557, 2006. © 2006 Society of Plastics Engineers