Development of Hydraulic Setting Adjustment in a Cone Crusher
Laitila, Jaakko Ilmari (2018)
2018
Konetekniikka
Teknisten tieteiden tiedekunta - Faculty of Engineering Sciences
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Hyväksymispäivämäärä
2018-05-09
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201804261571
https://urn.fi/URN:NBN:fi:tty-201804261571
Tiivistelmä
One of the most important parameters in rock crushing is the setting. This variable is the main factor that determines the maximum particle size that the crusher produces. In a cone crusher, the setting means the smallest gap between the two surfaces that are in-volved in the compression crushing. The rock is crushed between a moving and a fixed surface. Typically, the cone crusher’s setting can be hydraulically adjusted.
This thesis studies and further develops the hydraulic setting adjustment circuit in a newly developed cone crusher by Metso. This new crusher has a unique setting adjust-ment design compared to the previous models. In the prototype phase, the setting circuit has found to be slightly unstable and the setting increases unwantedly over time. This means that oil is leaking from the pressurized chamber that supports the crusher’s head. The automation system then needs to actively correct the setting to the desired value. Another instability of the setting is the excess hydraulic elasticity of the system. This shows as an oscillating position of the piston under a load. The goal of this thesis was to completely remove the piston sinking and diminish the elasticity.
The thesis consists of three parts: the analysis of the current hydraulic setting circuit, the development of the new circuit and reviewing the impacts of changes by analyzing the new results. The current circuit is studied based on the measurements done prior to this thesis and studying the components of the system. Based on these analysis, a design change that should fix the issues is suggested and implemented on a customer operated machine. New measurements are made and compared to previous results.
When analyzing the components and measurements of the system, it was noticed that the unwanted increase of the setting was caused by an incorrect machining of a certain pressure relieving valve’s cavity. This machining caused one of the seals to fail and oil was leaked to the reservoir. The problem was then related to quality, not engineering. The excess elasticity was determined to result from too much pressurized oil volume in hydraulic hoses. An electrically operated lock valve manifold, that was installed as close to the piston chamber as reasonable, was designed and installed as a solution. According to the results obtained from the testing, the unwanted setting increase was completely removed and the elasticity decreased 60 % from the initial situation.
This thesis studies and further develops the hydraulic setting adjustment circuit in a newly developed cone crusher by Metso. This new crusher has a unique setting adjust-ment design compared to the previous models. In the prototype phase, the setting circuit has found to be slightly unstable and the setting increases unwantedly over time. This means that oil is leaking from the pressurized chamber that supports the crusher’s head. The automation system then needs to actively correct the setting to the desired value. Another instability of the setting is the excess hydraulic elasticity of the system. This shows as an oscillating position of the piston under a load. The goal of this thesis was to completely remove the piston sinking and diminish the elasticity.
The thesis consists of three parts: the analysis of the current hydraulic setting circuit, the development of the new circuit and reviewing the impacts of changes by analyzing the new results. The current circuit is studied based on the measurements done prior to this thesis and studying the components of the system. Based on these analysis, a design change that should fix the issues is suggested and implemented on a customer operated machine. New measurements are made and compared to previous results.
When analyzing the components and measurements of the system, it was noticed that the unwanted increase of the setting was caused by an incorrect machining of a certain pressure relieving valve’s cavity. This machining caused one of the seals to fail and oil was leaked to the reservoir. The problem was then related to quality, not engineering. The excess elasticity was determined to result from too much pressurized oil volume in hydraulic hoses. An electrically operated lock valve manifold, that was installed as close to the piston chamber as reasonable, was designed and installed as a solution. According to the results obtained from the testing, the unwanted setting increase was completely removed and the elasticity decreased 60 % from the initial situation.