The diploma thesis deals with design and analsys of special flow rectifier, design of which, allows circulation of working fluid within magnetic refigerator system at minimal pressure losses through the core of refrigerator represented by regenerator. An important part of the diploma thesis is dedicated to research of liquid pressure drop through the assembly of rectifier and active magnetic regenerator. In the course of work, numerical analyzes were made and verified with measurements. Result of the measurements were used to characterize dynamics of the fluid flow. Result of the work serve for further development on prototype of the magnetic refigerator.