{HEAD ~ This invention} relates to {TAIL ~ an axial fan housing} having a metallic shielding grating covering an air passage opening, wherein the grating is formed with a series of vane like guide bars arranged in two or more concentric circular series 
{ HEAD ~ This invention } relates to { TAIL ~ an axial fan housing } having a metallic shielding grating covering an air passage opening , wherein the grating is formed with a series of vane like guide bars arranged in two or more concentric circular series
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