Static mixer for mixing urea aqueous solution and engine exhaust gas

Abstract

The present disclosure relates to a static mixer for mixing a urea solution and engine exhaust gas. The static mixer includes: an external tube including one end portion connected to an exhaust manifold of a diesel engine, the other end portion connected to an SCR (Selective Catalytic Reduction), and a part with which a urea solution injection adaptor is provided; an internal tube installed inside the external tube so as to have a constant gap between at least a part of an outer wall surface and an inner wall surface of the external tube; and a channel unit comprising a plurality of guiding channels provided inside the internal tube in a longitudinal direction, and having an inlet portion facing a lower end portion of the urea solution injector adaptor. The present disclosure may make the exhaust gas and the urea solution before passing through the SCR pass through the inlet portion and the plurality of guiding channels of the channel unit to form fine and even mixed gas, thereby largely decreasing an amount of nitride oxide (NOx) discharged to the air by improving a catalytic reduction reaction ratio in the SCR.

1 - 11 . (canceled) 
     
     
         12 . A static mixer for mixing a urea solution and engine exhaust gas, comprising:
 an external tube including one end portion connected to an exhaust manifold of a diesel engine, the other end portion connected to an SCR (Selective Catalytic Reduction), and a part with which a urea solution injection adaptor is provided; and   a channel unit provided inside the external tube, comprising a plurality of guiding channels in a longitudinal direction, and having an inlet portion facing a lower end portion of the urea solution injector adaptor.   
     
     
         13 . The static mixer for mixing a urea solution and engine exhaust gas of  claim 12 , further comprising:
 an internal tube installed inside the external tube so as to have a constant gap between at least a part of an outer wall surface and an inner wall surface of the external tube,   wherein the inlet portion is installed inside the internal tube.   
     
     
         14 . The static mixer of  claim 13 , wherein the internal tube includes at least one protrusion at an outer peripheral portion. 
     
     
         15 . The static mixer of  claim 13 , wherein the channel unit comprises a plurality of first channel plates arranged in the internal tube with predetermined intervals therebetween, and a plurality of second channel plates inclined at a predetermined angle with respect to the plurality of first plates and disposed to cross the plurality of first plates with predetermined intervals therebetween. 
     
     
         16 . The static mixer of  claim 15 , wherein an exposed portion of at least one of the plurality of first and second channel plates has at least one through hole so as to achieve a fine and even mixing behavior between the exhaust gas and the urea solution. 
     
     
         17 . The static mixer of  claim 15 , wherein a plurality of blades is provided at an end portion of an outlet side of at least one of the plurality of first and second channel plates so as to achieve a fine and even mixing behavior between the exhaust gas and the urea solution. 
     
     
         18 . The static mixer of  claim 17 , wherein the plurality of blades is inclinedly arranged in an opposite direction for each layer of the first and second channel plates. 
     
     
         19 . The static mixer of  claim 13 , wherein the inlet portion of the channel unit includes a first inclined portion having a predetermined angle with respect to a longitudinal direction of the internal tube, and a second inclined portion having a predetermined angle with respect to the first inclined portion. 
     
     
         20 . The static mixer of  claim 19 , wherein an orientation angle of the first inclined portion is 0 to 30° in an outside direction with respect to a virtual axial line perpendicular to the longitudinal direction of the internal tube. 
     
     
         21 . The static mixer of  claim 19 , wherein each of end surfaces of the first and second inclined portions at an end surface of an inlet side has a shape of a straight line, a curved line, or a combination thereof. 
     
     
         22 . The static mixer of  claim 15 , wherein the respective three first and second channel plates are included so as to form four rooms in one direction and the other direction, respectively. 
     
     
         23 . The static mixer of  claim 13 , wherein the gap between the internal tube and the external tube is 5 to 10 mm.