This master’s thesis is made to increase the understanding of the dynamic characteristics of a typical large swing check valve used in a system that transports pressurized water to a reactor tank.3D FSI-simulations are performed for a number of transients in order to study the dynamic characteristics their dependence of the deceleration rate. The purpose is to find information about the dynamics that could be used in a future improvement of a 1D-model.Steady state simulations are performed for angles in the whole spectrum. Seven transient FSI-simulations with different constantly decelerating flows from 630 kg/s2 (6.7 m/s2) to 40 320 kg/s2 (430 m/s2) have been performed. The pressure on the disc caused by the hydraulic torque is integrated and the corresponding torque contribution, together with the weight torque, is used in the second law of motion to calculate the movement of the disc throughout the transients.Steady state simulations yield the pressure drop over the valve, which could be compared with field measurements in order to validate the CFD-simulations. Comparison of the pressure distribution on the disc for the steady state and transient simulations shows the importance of taking the disc angular velocity into account when modelling in 1D. Correlations between the angle, angular velocity, torque and mass flow are obtained from the transient FSI-simulations. Torque coefficients according to (Li & Liou, Vol. 125) are also brought out from the simulated transients, but in order to create a model in line with this approach further simulations have to be performed. A prediction of the pressure rise that occurs when a swing check valve closes in backward flow according to the Joukowsky equation is brought out and gives an idea of the loadings that the system has to be able to handle.

Constant product development for integration and optimization is a crucial part of companies today. With industrial components comes the challenge with how these parts can be integrated and optimized the best for the system. One example is a hydraulic elevator system, to integrate and optimize the design, the rest of the valve system has to be taken into consideration. This thesis contains the integration and optimization of a check valve solution designed with the help of the product development process in hopes of reducing costs for the manufacturing process for the company. The thesis resulted in an optimized check valve solution with 6 bolts connected with the hydraulic elevator valve system. The requirements were fulfilled but some were not possible to achieve without a physical copy.

Skanska Grundläggning in Region Special wishes to gain an increased understanding of the extent to which it differs in the wear of percussion hammers and pilot drill crowns, depending on which driving medium is used in down-the-hole drilling, as well as logistical and economic aspects depending on the chosen method. Down-the-hole drilling means that the hammer works down in the borehole and forms one of the components at the far end of the drill string together with a drill bit. The blow of the hammer is created by air or water at high pressure. The piling method that is examined is drilled steel pipe piles, which means that a steel pipe pile is driven into the ground in step with the hammer and the drill bit's advancement. Once the desired depth has been reached, the drill string with the drill bit is pulled out of the casing and then the steel pipe pile is filled with concrete. The study aims to examine the products' lifespans and repair intervals from several different perspectives and set them against reality, as well as what the different methods have for differences regarding logistics and establishment. This is to create a basis for future decisions on the most suitable method of down-the-hole drilling. The beginning of the study consisted of qualitative preliminary interviews to identify and create a problem formulation that was dealt with via a literature study, five semi-structured interviews, eleven questionnaires, internal data from drilling protocols and purchasing. The result shows that there is some difference in wear in the hammer depending on whether it is an air or water powered system, the wear appears in different places and can have an impact on the life of the hammer. The wear that occurs most frequently on drill bit is grinding on the buttons. Geotechnical differences for various projects are a significant factor in the service life of the equipment. An air hammer requires that the air constantly being mixed with lubricating oil and that an air compressor consumes more diesel compared to a high-pressure pump for the equivalent water hammer. The handling of water that is flushed out of the borehole is considered a concern. To reduce wear on water hammers and thus fewer replacements and more repairs, a drill bit intended for water powered down-the-hole hammer should be used. DTH-drilling with an air hammer is considered an industry standard and a certain skepticism towards a water powered system may indicate inexperience. / Skanska Grundläggning inom Region Special önskar att få en ökad förståelse hur vida det skiljer sig vid slitage av hammare och pilotborrkrona beroende på vilket drivande medium som nyttjas vid sänkhammarborrning, samt logistiska och ekonomiska aspekter beroende på vald metod. Sänkhammarborrning innebär att hammaren arbetar nere i borrhålet och utgör en av komponenterna längst ut på borrsträngen tillsammans med en borrkrona. Hammarens slag skapas av luft eller vatten i högt tryck. Pålningsmetoden som undersöks är borrade stålrörspålar, det betyder att ett foderrör drivs ned i marken i takt med hammaren och borrkronans framfart. Väl när önskat djup uppnåtts lyfts borrsträngen med hammaren och piloten upp ur foderröret för att sedan fyllas upp med betong. Studien syftar till att undersöka produkternas livslängder och reparationsintervall från flera olika perspektiv och ställa dem emot verkligheten, samt vad dem olika metoderna har för olikheter kring logistik och etablering. Detta är för att skapa underlag för framtida beslut om mest lämplig metod av sänkhammarborrning. Studiens begynnelse bestod av kvalitativa förintervjuer för att identifiera och skapa en problemformulering som avhandlades via en litteraturstudie, fem semistrukturerade intervjuer, elva frågeformulär, interna data från borrningsprotokoll och inköp. Resultatet visar att det förekommer viss skillnad i slitage i hammaren beroende på om det är en luft- eller vattenanläggning, slitaget visar sig på olika ställen och kan ha betydelse för hammarens livslängd. Det slitage som uppträder mest frekvent på piloter är nedslipning av stift. Geotekniska egenskaper för olika projekt utgör en betydande faktor för utrustningens livslängd. En lufthammare är i behov av att luften konstant beblandas smörjolja och att en luftkompressor förbrukar mer diesel jämfört med en högtryckspump för motsvarande vattenhammare. Efterhanteringen av vatten som spolas upp anses vara ett bekymmer. För att minska slitage på vattenhammare och därmed färre byten och mer reparationer bör en pilotborrkrona avsedd för vattendriven sänkhammarborrning nyttjas. Sänkhammarborrning med lufthammare anses som branschstandard och en viss skepticism mot en vattendriven anläggning kan tyda på oerfarenhet.