Impeller having primary blades and secondary blades

Abstract

Provided is an impeller including a first portion including a first hub and a plurality of primary blades each extending while being spaced an equal distance from each other along an outer circumference of the first hub and a second portion including a second hub coupled to a lower side of the first hub by using a projection-groove coupling manner and a plurality of secondary blades each extending while being spaced apart from each other along an outer circumference of the second hub. Here, when a projection angle between a leading edge (L.E.) and a trailing edge (T.E.) of each of the primary blades is Φ1, and a projection angle between a leading edge (L.E.) and a trailing edge (T.E.) of each of the secondary blades is θ1, the projection angle Φ1 and θ1 includes an upstream angle Φ1u and θ1u and a downstream angle Φ1d and θ1d, at which the primary blade and the secondary blade overlap each other, and an angle Φ1m and θ1m at which the primary blade and the secondary blade do not overlap each other, and the projection angle θ1 is less than the projection angle Φ1 to satisfy an equation 0<θ1<Φ1 as a radius of each of the primary blade and the secondary blade goes from the hub to the edge.

1 . An impeller comprising:
 a first portion comprising a first hub and a plurality of primary blades each extending while being spaced an equal distance from each other along an outer circumference of the first hub; and   a second portion comprising a second hub coupled to a lower side of the first hub by using a projection-groove coupling manner and a plurality of secondary blades each extending while being spaced apart from each other along an outer circumference of the second hub,   wherein when a projection angle between a leading edge (L.E.) and a trailing edge (T.E.) of each of the primary blades is Φ 1 , and a projection angle between a leading edge (L.E.) and a trailing edge (T.E.) of each of the secondary blades is θ 1 ,   the projection angle Φ 1  and Φ 1  comprises an upstream angle   1   1u  and θ 1u  and a downstream angle Φ 1d  and θ 1d , at which the primary blade and the secondary blade overlap each other, and an angle Φ 1m  and θ 1m  at which the primary blade and the secondary blade do not overlap each other, and   the projection angle θ 1  is less than the projection angle Φ 1  to satisfy an equation 0<θ 1 <Φ 1  as a radius of each of the primary blade and the secondary blade goes from the hub to the edge.   
     
     
         2 . The impeller of  claim 1 , wherein the angles θ 1u  and θ 1d  of the secondary blade have magnitudes overlapping the primary blade so that a channel around a downstream of a negative-pressure surface of the primary blade is guided. 
     
     
         3 . The impeller of  claim 1 , wherein the first hub comprises a plurality of first coupling projections, which are spaced apart from each other on a bottom surface thereof, and a plurality of first coupling grooves that are provided by the plurality of first coupling projections,
 the second hub comprises a plurality of second coupling projections, which are spaced apart from each other on a top surface thereof, and a plurality of second coupling grooves that are provided by the plurality of second coupling projections,   the plurality of first coupling projections are coupled to the plurality of second coupling grooves, and   the plurality of second coupling projections are coupled to the plurality of first coupling grooves.   
     
     
         4 . The impeller of  claim 3 , wherein the plurality of first coupling projections are coupled to the plurality of second coupling grooves in a pressing manner, and
 the plurality of second coupling projections are coupled to the plurality of first coupling grooves in a pressing manner.   
     
     
         5 . The impeller of  claim 3 , wherein the plurality of first coupling projections are coupled to the plurality of second coupling grooves by using an adhesive, and
 the plurality of second coupling projections are coupled to the plurality of first coupling grooves by using an adhesive.   
     
     
         6 . The impeller of  claim 1 , wherein each of the first hub and the second hub has a band shape. 
     
     
         7 . The impeller of  claim 1 , wherein the first and second hubs form a single cone shape when coupled to each other. 
     
     
         8 . An impeller comprising:
 a first portion comprising a circular bottom plate, a hub protruding from a central portion of a top surface of the circular bottom plate, and a plurality of primary blades formed in a circumferential direction with respect to the hub while being spaced an equal distance from each other on the top surface of the circular bottom plate; and   a second portion comprising a shroud having a band shape and a plurality of secondary blades spaced a distance from each other along a bottom surface of the shroud in an integrated manner,   wherein when an inlet area between a negative-pressure surface of the primary blade and a pressure surface of the secondary blade is Ssu, an inlet area between the pressure surface of the primary blade and a negative-pressure surface of the secondary blade is Spu, a downstream area of a channel of the negative-pressure surface of the primary blade, which is an area at a downstream of each channel, is Ssd, and a downstream area of a channel of the pressure surface of the primary blade is Spd,   an outlet angle of the secondary blade is equal to that of the primary blade,   an inlet of the secondary blade is disposed at a position at which an S-shape is varied, and   an inlet angle of the secondary blade allows a tangent line of a flow angle to coincide with a primary streamline of the channel.   
     
     
         9 . The impeller of  claim 8 , wherein a leading edge (L.E.) of the secondary blade is disposed between channels having the same radial inlet so hat the areas Ssu and Spu are equal to each other. 
     
     
         10 . The impeller of  claim 8 , wherein an outlet angle and an outlet position between channels are set by rotating a trailing edge (T.E.) of the secondary blade to be disposed between channels having the same radial outlet by using a leading edge (L.E.) of the secondary blade as a pivot point, thereby maintaining the areas Ssu and Ssd are similar to each other. 
     
     
         11 . The impeller of  claim 8 , wherein the shroud has a band shape. 
     
     
         12 . The impeller of  claim 8 , wherein a plurality of first coupling groove, to which lower edges of the plurality of secondary blades are inserted, are defined in the top surface of the bottom plate, and
 a plurality of second coupling groove, to which upper edges of the plurality of primary blades are inserted, are defined in the bottom surface of the shroud.   
     
     
         13 . The impeller of  claim 12 , wherein the lower edges of the plurality of secondary blades are coupled to the plurality of first coupling grooves in a pressing manner, and
 the lower edges of the plurality of primary blades are coupled to the plurality of second coupling grooves in a pressing manner.   
     
     
         14 . The impeller of  claim 12 , wherein the lower edges of the plurality of secondary blades are coupled to the plurality of first coupling grooves by using an adhesive, and
 the lower edges of the plurality of primary blades are coupled to the plurality of second coupling grooves by using an adhesive.   
     
     
         15 . The impeller of  claim 1 , wherein the plurality of secondary blades each disposed between each of the primary blades are spaced different distances from each other along a rotation direction of the impeller. 
     
     
         16 . The impeller of  claim 8 , wherein the circular bottom plate and the shroud are inclined in a flow downstream direction or formed in a horizontal direction. 
     
     
         17 . The impeller of  claim 16 , wherein the circular bottom plate has an outer diameter less than an inner diameter of the shroud. 
     
     
         18 . The impeller of  claim 16 , wherein the plurality of primary blades and the plurality of secondary blades are coupled to the circular plate and the shroud in an integrated manner. 
     
     
         19 . The impeller of  claim 8 , wherein the plurality of secondary blades each disposed between each of the primary blades are spaced different distances from each other along a rotation direction of the impeller.