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Design of blow line resin injector for MDF production
2007 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

This master’s thesis work was carried out at autumn 2006 on Metso Panelboard in Sundsvall (Sweden). Metso Panelboard is one of the leading suppliers of engineering know-how, technology and after-market services for the production of medium density fibreboards (MDF). The objective for this thesis is to design a way of adding the resin into the blow line such that the resin (glue) consumption is reduced. The resin stands for 30 % of the total cost of a MDF board. By keeping the resin consumption down i.e. the mixing as efficient as possible, the total cost of the boards can hence be significantly reduced. The resin binds the fibres in the MDF board together and gives the board its strength. One way to improve the board strength is to increase the number of connections from fibre to fibre, with is achieved by better blending and resin distribution. The resin injector is positioned on the blow line where fibre and steam are flowing from the refiner to the dryer. After a litterature survey of the research and the theories about resin consumption, four main issues was identifyed. These are resin drop size, blow line turbulence, fibre penetration and pre-curing. This led to the design guidelines atomisation, adjustment, placing, angles of the injectors and maintenance. Because of the lack of information and reports regarding this subject the design could not be connected directly to resin consumption. Compared to today’s design, the design proposed in this thesis is a more mechanical advanced and probably more reliable design with a self-cleaning function. This concept was chosen based on the idea to use one self-controlling resin injector. The injector controls the pressure difference with the plunger that adjusts the column to get the right area of the annular gap. Controlling the pressure difference gives a possibillity to minimise the drop size regardless of the flow rate. The plunger will also clean the orifice between resin recipe changes or when the resin flow stops. The plunger will further protect the internal of the injector from fibres in the blow line, when there is no flow through the injector. To ensure the function, flow calculation and computational fluid dynamic (CFD) simulations were performed. Complete drawings were produced for the design so that a prototype can be manufactured and tested in the future.

Place, publisher, year, edition, pages
Keyword [en]
Technology, Medium density fibreboard, MDF
Keyword [sv]
URN: urn:nbn:se:ltu:diva-48154ISRN: LTU-EX--07/053--SELocal ID: 5a093239-c493-46d0-86aa-a5702bda10c6OAI: diva2:1021493
Subject / course
Student thesis, at least 30 credits
Educational program
Mechanical Engineering, master's level
Validerat; 20101217 (root)Available from: 2016-10-04 Created: 2016-10-04Bibliographically approved

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