Multi-purpose blowing apparatus

Abstract

A multi-purpose blowing apparatus is provided, in particular for use in the agricultural field and the like, comprising an engine ( 2 ), a fan wheel ( 3 ) moved by the engine and adapted to generate a delivery air flow ( 4 ), and a volute header ( 5 ) surrounding said fan wheel ( 3 ) and adapted to convey said delivery flow ( 4 ) towards use means; said fan wheel comprises a support element ( 13 ) presenting a first a second face ( 13 a, 13 b ) mutually opposite and respectively invested by a first and a second air flows ( 10, 11 ) coming from mutually opposite directions, a predetermined number of blades emerging from said second face ( 13 a ) and at least one air passage ( 13 c ) provided in the support element ( 13 ) and adapted to direct at least said first air flow ( 10 ) through said support element ( 13 ).

1 . A multi-purpose blowing apparatus, in particular for use in the agricultural field and the like, comprising: 
 an engine ( 2 ),    a fan wheel ( 3 ) moved by the engine and adapted to generate a radial delivery air flow ( 4 ), and a volute header ( 5 ) surrounding said fan wheel ( 3 ) and adapted to convey said radial delivery flow ( 4 ) at least partly towards provided use means,    wherein said fan wheel comprises: 
 a support element ( 13 ) presenting a first face ( 13   a ) and a second face ( 13   b ) mutually opposite to said first face ( 13   a ), said first and second faces ( 13   a ,  13   b ) being respectively invested at least by a first and a second air flows ( 10 ,  11 ) coming from mutually opposite directions;  
 a predetermined number of blades emerging from said second face ( 13   b ); and  
 at least one air passage ( 13   c ) provided in the support element ( 13 ) and adapted to direct at least said first air flow ( 10 ) investing said first face ( 13   a ) at least partly through said support element ( 13 ).  
   
     
     
         2 . The apparatus s claimed in  claim 1 , wherein said air passage ( 13   c ) is aerodynamically connected to said blades, the blades and the air passage ( 13   c ) cooperatively defining said radial delivery air flow ( 4 ), said radial delivery air flow ( 4 ) substantially resulting from mixing and/or confluence of said air flows ( 10 ,  11 ).  
     
     
         3 . The apparatus as claimed in  claim 1  or  2 , wherein said air flows ( 10 ,  11 ) are substantially axial and opposite to each other at least at the centrifugal fan wheel ( 3 ) entry.  
     
     
         4 . The apparatus as claimed in  claim 1 , wherein said support element ( 13 ) comprises a hub portion ( 14 ) pivotally engaged about a rotation axis ( 2   a ), a central portion ( 15 ) radially extending from said hub portion ( 14 ) and a peripheral portion ( 16 ) axially displaced along said rotation axis ( 2   a ) with respect to said central portion ( 15 ), said air passage ( 13   c ) being defined by an ideal surface lying between said central portion ( 15 ) and said peripheral portion ( 16 ).  
     
     
         5 . The apparatus as claimed in  claim 4 , wherein said central portion ( 15 ) is lying on a first plane transverse to the rotation axis ( 2   a ), said peripheral portion ( 16 ) lying on a second plane substantially parallel to said first plane and axially displaced, along the rotation axis ( 2   a ), by a predetermined distance, said air passage ( 13   c ) being defined by a cylindrical surface between said central portion ( 15 ) and said peripheral portion ( 16 ).  
     
     
         6 . The apparatus as claimed in  claim 4 , wherein said blades comprise first blades ( 8 ) having a first root portion ( 8   a ) located on the central portion ( 15 ) and a first tip portion ( 8   b ) radially opposite to said first root portion ( 8   a ) and located on the peripheral portion ( 16 ).  
     
     
         7 . The apparatus as claimed in  claim 4 , wherein said blades comprise second blades ( 9 ) having a second root portion ( 9   a ) located in correspondence of said air passage ( 13   c ) and a second tip portion ( 9   b ) radially opposite to said second tip portion ( 9   a ) and located on the peripheral portion ( 16 ).  
     
     
         8 . The apparatus as claimed in  claim 1 , wherein said engine ( 2 ) is disposed along the path of at least one of said first and/or second air flows ( 10 ,  11 ), so that at least said first air flow ( 10 ) defines an aspiration flow for engine cooling, generated by the corresponding first and/or second blades ( 8 ,  9 ) of said centrifugal fan wheel ( 3 ).  
     
     
         9 . The apparatus as claimed in  claim 8 , wherein said first and/or second blades ( 8 ,  9 ) generate said first air flow ( 10 ) for engine cooling having a flow rate adapted to complete cooling of the engine ( 2 ), so that said radial delivery air flow ( 4 ) can be completely conveyed from said volute header ( 5 ) to said provided use means.  
     
     
         10 . The apparatus as claimed in  claim 8 , comprising an engine-holding casing ( 12 ) having ventilation openings ( 12   a ) to be passed through by said first air flow ( 10 ) for engine cooling.  
     
     
         11 . The apparatus as claimed in  claim 10 , wherein said engine-holding casing ( 12 ) has a shell-like conformation and is connected at an attachment edge ( 12   b ) thereof with said volute header ( 5 ).  
     
     
         12 . The apparatus as claimed in  claim 11 , wherein said ventilation openings ( 12   a ) are disposed in a bottom wall ( 12   c ) of said casing ( 12 ) substantially transverse to the axis ( 2   a ) of the engine ( 2 ) and positioned on the opposite side from said attachment edge ( 12   b ).  
     
     
         13 . The apparatus as claimed in  claim 12 , wherein said ventilation openings ( 12   a ) are placed at least partly in a region of said bottom wall ( 12   c ) of the casing ( 12 ) substantially disposed close to said first and/or said second blades ( 8 ,  9 ).  
     
     
         14 . The apparatus as claimed in  claim 6 , wherein the first and/or the second blades ( 8 ,  9 ) during suction generate a second air flow ( 11 ) returned through at least one feeding opening ( 5   a ) defined by said volute ( 5 ) and opposite to the first blades ( 8 ).  
     
     
         15 . The apparatus as claimed in  claim 6 , wherein said feeding opening ( 5   a ) extends coaxially with the axis ( 2   a ) of said engine ( 2 ), at a region radially internal at least to said second blades ( 9 ).  
     
     
         16 . The apparatus as claimed in  claim 10 , wherein said engine-holding casing ( 12 ) comprises walls adapted to sound insulation.  
     
     
         17 . The apparatus as claimed in  claim 16 , wherein said engine-holding casing ( 12 ) comprises a predetermined number of internal walls ( 17   a ) cooperatively defining an acoustic labyrinth adapted to hamper the sound diffusion towards the external environment.  
     
     
         18 . The apparatus as claimed in  claim 12 , wherein said engine-holding casing ( 12 ) comprises air-permeable acoustic filters ( 17   b ) at least partly immersed in the first and/or second air flows ( 10 ,  11 ) within the engine-holding casing ( 12 ).  
     
     
         19 . The apparatus as claimed in  claim 1 , further comprising means for back-holding ( 18 ) adapted to engage the apparatus ( 1 ) to an operator's back.  
     
     
         20 . The apparatus as claimed in  claim 19 , wherein said means for back-holding ( 18 ) comprise a predetermined number of suspenders ( 18   a ) and a framework ( 18   b ) connected to the apparatus ( 1 ) and bearing said suspenders ( 18   a ).