Not able to snap Fluid Region properly
 

Hi All,
I am currently working on the simulation of water flow in pipe which has Static Mixer.Main aim of the simulation is to estmate pressure drop. I have created geometry using salome and tried to mesh it using snappyHexMesh. However, Static Mixer geometry which should be removed from the BlockMesh is not getting removed properly. In short Snapping is not done properly. I have attached Screenshot of geometry, Portion which should be removed and Resulted mesh. Please suggest me some solution for the meshing