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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Correlations between fibre properties and paper properties / Inverkan av fiberegenskaper på pappersegenskaper

Johansson, Anna January 2011 (has links)
The understanding of what properties the fibre should have in order to give the right end-product paper properties, along with the type of processing, is a subject for a lot of research and development. Today the ability to measure fibre properties on-line is widely used for pulps. It is often necessary to measure many properties and variables in a process. The data collected is therefore almost always multivariate. It is very hard to analyse process data due to a lot of noises. Correlations between fibre and paper properties are hard to find, but this does not mean that correlations do not exist. Fibre properties, measured by the pulp analyser PulpEye, were investigated and correlations to paper properties were studied. The work was divided into three different studies. Study 1 was an investigation of historical process data, in study 2 pulp samples from the production was analysed and study 3 was a refiner setting trial, were different refiner segments, flows through refiners and intensities were studied. Both the group-plots and MVDA’s based on the historical process data in study 1, showed that the Scott Bond was increased with increased amount of kinks and curl for the unbleached pine pulp (softwood pulp). Coarseness measurements, made in the study of historical data, indicated that the coarseness was varying in such a large extent that it was believable that it had effects in the papermaking process. Another interesting fibre property, investigated in the refiner setting trial, was crill. The amount of crill is said to have strong correlation to paper strength. The analysis showed that the incoming pulp had different amount of crill and that the amount of crill after the refiners also was varying for the different samples. The development of crill at different kappa numbers and for pulps refined with different segments and refiner strategies should be further investigated. In this work it has been difficult to find correlations between fibre properties and paper properties in the refiner setting trial. This could have been due to small variations of the different parameters. This work showed that the normal production can be handled very well and variations are rather small. It can be seen though, that problems do appear when parameters are deviating from the normal case. An efficient way to work is to do measurements when the incoming pulp parameters are deviating. It should also be more investigated how the most common deviating pulp parameters should be handled in the refining process and at the board machine. The communication between the pulp production and the board machines is recommended to be further developed, especially when the pulp production have disturbances that can be affecting the refining and further the board production.
2

Correlations between fibre properties and paper properties / Inverkan av fiberegenskaper på pappersegenskaper

Johansson, Anna January 2011 (has links)
The understanding of what properties the fibre should have in order to give the right end-product paper properties, along with the type of processing, is a subject for a lot of research and development. Today the ability to measure fibre properties on-line is widely used for pulps. It is often necessary to measure many properties and variables in a process. The data collected is therefore almost always multivariate. It is very hard to analyse process data due to a lot of noises. Correlations between fibre and paper properties are hard to find, but this does not mean that correlations do not exist. Fibre properties, measured by the pulp analyser PulpEye, were investigated and correlations to paper properties were studied. The work was divided into three different studies. Study 1 was an investigation of historical process data, in study 2 pulp samples from the production was analysed and study 3 was a refiner setting trial, were different refiner segments, flows through refiners and intensities were studied. Both the group-plots and MVDA’s based on the historical process data in study 1, showed that the Scott Bond was increased with increased amount of kinks and curl for the unbleached pine pulp (softwood pulp). Coarseness measurements, made in the study of historical data, indicated that the coarseness was varying in such a large extent that it was believable that it had effects in the papermaking process. Another interesting fibre property, investigated in the refiner setting trial, was crill. The amount of crill is said to have strong correlation to paper strength. The analysis showed that the incoming pulp had different amount of crill and that the amount of crill after the refiners also was varying for the different samples. The development of crill at different kappa numbers and for pulps refined with different segments and refiner strategies should be further investigated. In this work it has been difficult to find correlations between fibre properties and paper properties in the refiner setting trial. This could have been due to small variations of the different parameters. This work showed that the normal production can be handled very well and variations are rather small. It can be seen though, that problems do appear when parameters are deviating from the normal case. An efficient way to work is to do measurements when the incoming pulp parameters are deviating. It should also be more investigated how the most common deviating pulp parameters should be handled in the refining process and at the board machine. The communication between the pulp production and the board machines is recommended to be further developed, especially when the pulp production have disturbances that can be affecting the refining and further the board production.
3

Development of a Profile Sample Cutter / Utveckling av en profilskärare

Tarik Hamad, Maryam January 2020 (has links)
The pulp- and paper industry is a key industry globally and stands for a production of 600 million tonnes pulp and paper worldwide with a total revenue of 400 billion dollars. Due to high quality requirements on paper, it is important to use instruments that control that the produced paper fulfill the promised requirements. To control the quality, a sample strip needs to be taken along the full length of each paper reel. The purpose of this master’s thesis project was consequently to develop a unit that will be used when cutting out these samples.  The project started with a pre-study on existing sample cutters to define all integrated subsystems and their functionalities, advantages and drawbacks. The essential subsystems were found to be: (1) paper reel cutting, (2) path movement, (3) motion generation and (4) mechanical transmission. The advantages and drawbacks were found by interviewing people who have used the cutters or in any way have encountered them for opinions, experience and knowledge. Sample winding is an additional subsystem which was found in a few of the existing cutters but was not further studied.  After defining were the problems and development potentials lay, a range of concepts were generated for the subsystems. These concepts were presented to a defined target group to ensure a unit which will create costumer value. By taking their views and ideas into account, further concept development was made. After a few iterations, one concept was chosen for each subsystem in an evaluation with domain experts.  A detail study and design were then made which incorporated all subsystems into one unit. The solution: (1) has two rotating circular blade pushed against sharp guide rails, (2) is hand-held with two pair of wheels on the cutter-head and a digital inclinometer, (3) has a manually generated motion and (4) uses a synchronous belt drive which transfer the manually generated motion to the rotating blades. In addition to this, complete 2D and 3D drawings, along with a bill of materials, were delivered for the future manufacturing of the unit.  Since this thesis presents no solution for the sample winding, the next step is to develop a collector which is easily handled and should be able to co-use the manually generated power with the rotating blades. Further, a design which allows modularization of the unit should be developed. / Pappersindustrin är en nyckelindustri globalt och står för en produktion på 600 miljoner ton pappersmassa och papper över hela världen med en total intäkt på 400 miljarder dollar. På grund av höga kvalitetskrav på papper är det viktigt att använda instrument som kontrollerar att det producerade papperet uppfyller de utlovade kraven. För att kontrollera kvaliteten måste en provremsa tas längs hela pappersrullen. Syftet med denna masteruppsats var följaktligen att utveckla en enhet som kommer att användas vid utskärning av dessa prover.  Projektet startades med en förstudie av befintliga provskärare för att definiera alla integrerade delsystem och deras funktioner, fördelar och nackdelar. De väsentliga delsystemen visade sig vara: (1) skärning av pappersrulle, (2) rörelse av vägar, (3) generering av rörelse och (4) mekanisk kraftöverföring. Fördelarna och nackdelarna hittades genom att intervjua personer som har använt skärarna eller på något sätt har stött på dem för åsikter, erfarenhet och kunskap. Upprullning av proverna är ett ytterligare delsystem som hittades i vissa befintliga skärare men studerades inte vidare.  Efter att ha definierat var problemen och utvecklingspotentialerna låg, genererades ett antal lösningar för delsystemen. Dessa koncept presenterades för en definierad målgrupp för att säkerställa en enhet som skapar kundvärde. Genom att ta hänsyn till deras åsikter och idéer, vidareutvecklades lösningarna. Efter några iterationer valdes ett koncept för varje delsystem i en utvärdering med domänexperter.  En detaljstudie och -design gjordes sedan som inkluderade alla delsystem i en enhet. Lösningen: (1) har två roterande cirkulära knivar tryckta mot vassa styrskenor, (2) är handhållen med två par hjul på skärhuvudet och en digital lutningsmätare, (3) har en manuellt genererad rörelse och (4) använder en synkroniserad remdrivning som överför den manuellt genererade rörelsen till de roterande bladen. Utöver detta levererades kompletta 2D- och 3D-ritningar tillsammans med en stycklista för den framtida tillverkningen av enheten.  Eftersom den här rapporten inte innehåller någon lösning för upprullning är nästa steg att utveckla en provupprullare som är lätt att hantera och bör kunna använda den manuellt genererade effekten. Vidare bör en design som möjliggör modulering av enheten utvecklas.

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