This master thesis reviews advances in detection and diagnosis of static friction (stiction) in Control valves. Control valves suffering from stiction results in oscillating control loops which in turn decreases both the process stability and reliability. Perstorp AB sees a necessity to automatically detect stiction in valves before the effects of the malfunctioning valves have become too severe. This thesis presents an introduction to maintenance, control loops and how stiction in valves can affect performance of control loops.A selection of methods presented in the literature are introduced and examined using normal operating data from the site in Perstorp. Common for all selected methods is their intuitive ideas and that they are based on normal operating data and minimum amount of process knowledge.

In this bachelor thesis, diagnostic methods for one of Siemens stem inlet Control valves have been developed. The work has taken place during ten weeks at Siemens Industrial Turbomachinery AB in Finspång. The company produce steam- and gas turbines and also provides service and maintenance. The purpose with this project has been to develop diagnostic methods that oversee the health of the Control valves. By using the developed methods you will know when it?s time for maintenance.

This is a report written for an examination project C-level, on the subject of energy. The examination project is a product of the FVB Sweden AB (district heating bureau). It started with a meeting with Stefan Jonsson FVB Sweden AB, were he explained the content of the project, and from this a presentation of the problem was made. The problem that needed to be solved was how they could control the valves in the system to provide heating to everyone in the system. The valves are often oversized so the pump in the heating plant would have to be enormous to be able to provide enough flow to be sufficient, if everyone in the system had there valves fully opened. I came up with two solutions to the problem, one was a wireless network that could keep track of the valves and the other solution was an extra sensor that was placed on the radiator.

This thesis considers the development of the software for an, newly developed, embedded real-time control system, based on a Periferal Interface Controller (PIC). The control system is developed to be used for several different applications. In this thesis work, software for two different applications are developed. The first task is a time controlled system, while the other task is implementation of aPI-/PID-controller. A user interface is also developed and implemented.The time controlled system is an automatic horse feeder, which is used for feeding horses at certain predefined points in time.

This thesis describes how a cost reduction project was done on the Packsize ondemand packing machine EM7. The cost reduction was achieved by making minorredesigns of the EM7.The project began by studying the EM7´s structure and function by working on itsassembly line. A short literature study on the subject Design for Manufacturing wasalso done.By working on the assembly line and by speaking with staff from production anddevelopment departments, a number of ideas for reducing manufacturing costs arose.Estimations of the potential cost reduction size for each proposal were done incollaboration with vendors and the purchasing department. Based on the size of the cost reduction, technical risk, impact on the assembly lineand the development time the various proposals were ranked. The two highestranked proposals were selected for further development towards finished solutions.One of the ideas that were selected to develop in to a finished solution meant thatsome of the pneumatic valves were replaced with others.

This report treats two assignments that concerns the biofuel furnace at Billerud Skärblacka AB and how these assignments were solved. The assignments were: reducing the number of CO-spikes and tuning the overfire air control loop. To reduce the number of CO-spikes the possibility that skewness in mass distribution affects the number of CO-spikes were study. The skewnwss of mass distribution was controled and adjusted with two experiments. The conclusion that was made is that the skewness of mass distribution were not sufficient enough to affect the number of CO-spikes.

This report contains a degree project made by the mechanical engineering students Lennart Andersson and Daniel Jansson. The project has performed in assignment by SOMAS Valves AB in Säffle. SOMAS are leading in development on control and on/off valves. To maintain this position they always want to improve their products. One way in this development is valves that are more tightened.The purpose with our project was to investigate another seat design on a HiCo (High Cobalt Alloy) seat to a SKV 150 PN 25 valve and compare this to an original HiCo seat.By modifying the seat on a ball valve we want to achieve a valve that leaks lesser then a valve whit original seat.

In Uppsala CHP Plant, there are six pressure reducing valves to reduce the pressure from 15 to 3 bars, before six absorption heat pumps. During the process the energy is conserved but losses occur in form of exergy. The aim of this thesis is to reduce the losses of exergy. This can be done by letting turbines replace the pressure reducing valves.In this thesis an investigation has been done of the conditions today, the conditions after the change from pressure reducing valves to turbines and a comparison of three different types of turbine solutions. The three examined solutions are one turbine, several helical screw expanders and several small turbines in parallel with asynchronous generators.The six absorption heat pumps have been divided into two groups; one group of four and one group of two absorption heat pumps.

To achieve an optimal combustion, an even air/fuel ratio in the combustion chamber is required. An optimal combustion leads to reduced amount of emissions due to a more complete combustion, which is an important matter because of the sharpened environmental laws. This can be attained, among other things, by applying entirely variable cam times. To optimize the engines efficiency and its emissions at all workloads and speeds, an active valve control can be applied. This means that the intake and exhaust-valves can be opened and closed at any time, independent of the crankshaft position.

In industrial control systems PID-control remains the prevalent strategy, also for processes that would benefit from model based control. The purpose of this thesis is to evaluate whether model based control can be readily implemented in an industrial control system. To this end a simulated surge tank with a simulated industrial control system is studied. For evaluation two scenarios with specified objectives are selected.Following a review of LQR and versions of MPC, Predictive Functional Control (PFC) is considered the most suitable for implementation. PFC is a form of MPC developed with industrial applications in mind and therefore has several advantages for implementation in an industrial control system.

Title: Co-operative, prevent or complement? - An essay on the relationships between control systems. Authors: Kim Eriksson and Victoria KarlssonPurpose: The essay aims to describe the relations between control systems and how they related to each other, based on an operationalization of the control systems. Research question: What are the control systems relations to each other? With regards whether control systems co-operative, prevents and/or complement each other.Theoretical framework: The essays theoretical framework is based on Malmi and Browns (2008) description of five different control systems and control mechanisms associated with each control system.   Research methodology: The method was based on three different data collection methods. These methods were observations, documentation, and semi-structured interviews.Conclusions: It is concluded that the control systems has comprehensive relations. Control systems have more, than one, relation to each other..

The secondary control must be part of the production plan, since the capacity will bedeployed in advance, just as the primary control. The activation of the new frequencycontrol should be preformed in Vattenfall's operations centers (DC) to minimizecommunication delay. Vattenfall needs to work towards a more holistic optimizationsystem. The main issue for Vattenfall Generation is not how we produce but ratherwhen, which is done with creation of bids. This is where there is the mostopportunity for improvement.

Studier har visat att det finns ett samband mellan syskonplacering och locus of control, medan andra studier inte funnit något samband. Syftet med denna studie är att undersöka relationen mellan syskonplacering, kön och locus of control ur ett hälsoperspektiv hos gymnasieelever i årskurs 3. I undersökningen deltog 147 gymnasielever ifrån fem skolor i Kronobergs län. Resultatet visade att kön och syskonplacering samvarierade med intern health locus of control (F= 3,01;p< 0,03; ES= 6,2) och att syskonplacering och kön tillsammans inte visade någon signifikant inverkan på extern health locus of control (F= 2,20;p=<0,09; ES= 4,6). Fyndet kan indikera att manliga mellanbarn i större utsträckning strävar efter en intern health locus of control än kvinnliga mellanbarn.Nyckelord: Syskonplacering, health locus of control, intern- och extern locus of control, kön..

This thesis aims to develop a control system for measuring electromagnetic compability (EMC). This has meant that a controller designed around an ATmega8 microcontroller has been manufactured and programmed. It has also meant the development of a comprehensive control software in the program MATLAB. The control system has been tested with satisfactory results and can now, monitor and control measurements of the EMC-type..

Title: Co-operative, prevent or complement? - An essay on the relationships between control systems. Authors: Kim Eriksson and Victoria KarlssonPurpose: The essay aims to describe the relations between control systems and how they related to each other, based on an operationalization of the control systems. Research question: What are the control systems relations to each other? With regards whether control systems co-operative, prevents and/or complement each other.Theoretical framework: The essays theoretical framework is based on Malmi and Browns (2008) description of five different control systems and control mechanisms associated with each control system.   Research methodology: The method was based on three different data collection methods. These methods were observations, documentation, and semi-structured interviews.Conclusions: It is concluded that the control systems has comprehensive relations. Control systems have more, than one, relation to each other..