A road cleaning machine comprising a centrifugal fan assembly

Abstract

Disclosed is a road cleaning machine including a centrifugal fan assembly that includes a fan casing including a casing inlet and a casing outlet and an impeller mounted in the fan casing and rotatable about an axis of rotation for drawing fluid from the casing inlet and directing the fluid to the casing outlet, the impeller includes a splitter wall extending outwardly from the axis of rotation to define first and second blade chambers extending from first and second faces of the splitter wall respectively, the splitter wall including a splitter wall aperture, a plurality of blades being mounted in the first and second blade chambers the impeller being configured to, during rotation about the axis of rotation, direct fluid from the casing inlet through the first and second blade chambers to the fan casing outlet, the fluid being directed into the second blade chamber via the splitter wall aperture.

1 . A road cleaning machine comprising a centrifugal fan assembly, wherein the centrifugal fan assembly comprises:
 a fan casing comprising a casing inlet and a casing outlet;   an impeller mounted in the fan casing and rotatable about an axis of rotation for drawing fluid from the casing inlet and directing the fluid to the casing outlet, the impeller comprising:
 a splitter wall extending outwardly from the axis of rotation to define first and second blade chambers extending from first and second faces of the splitter wall respectively, wherein the splitter wall comprises a splitter wall aperture; and 
 a plurality of blades mounted in the first and second blade chambers, 
 wherein the impeller is configured to, during rotation about the axis of rotation, direct fluid from the casing inlet through the first and second blade chambers to the casing outlet, the fluid being directed into the second blade chamber via the splitter wall aperture. 
   
     
     
         2 . The road cleaning machine of  claim 1  wherein the impeller further comprises a hub portion rotatably mounted to the fan casing. 
     
     
         3 . The road cleaning machine of  claim 2  wherein the impeller further comprises:
 a first impeller wall comprising a first impeller wall aperture for directing fluid from the inlet into the first and second blade chambers and extending outwardly from the axis of rotation of the impeller; and 
 a second impeller wall which is parallel to and spaced apart from the first impeller wall and is adjacent to the hub portion. 
 
     
     
         4 . The road cleaning machine of  claim 3  wherein the splitter wall is disposed between and/or parallel to the first and second impeller walls. 
     
     
         5 . The road cleaning machine of  claim 3 or 4  wherein the plurality of blades extend continuously from the second impeller wall to the splitter wall. 
     
     
         6 . The road cleaning machine of  claim 3  wherein the plurality of blades extend continuously from the splitter wall to the first impeller wall. 
     
     
         7 . The road cleaning machine of  claim 3  wherein the splitter wall is located substantially midway between the first and second impeller walls. 
     
     
         8 . The road cleaning machine of  claim 3  wherein the first impeller wall aperture and splitter wall aperture are centred about the axis of rotation. 
     
     
         9 . The road cleaning machine of  claim 3  wherein the first impeller wall aperture is located in and/or adjacent to the casing inlet. 
     
     
         10 . The road cleaning machine of  claim 3  wherein the splitter wall aperture is located in and/or adjacent to the first impeller wall aperture. 
     
     
         11 . The road cleaning machine of  claim 1  wherein the impeller comprises an open outer impeller edge through which the first and second blade chambers are in direct fluid communication with the casing outlet. 
     
     
         12 . The road cleaning machine of  claim 1  wherein the splitter wall comprises a splitter wall main body from which the plurality of blades extend and a splitter wall guide wall extending from the splitter wall main body to the splitter wall aperture, wherein the splitter wall guide wall is configured to separate fluid flowing from the inlet into the first and second blade chambers. 
     
     
         13 . The road cleaning machine of  claim 12  wherein the splitter wall guide wall is annular. 
     
     
         14 . The road cleaning machine of  claim 12  wherein the splitter wall guide wall comprises:
 a splitter wall ring portion; and/or 
 a splitter wall curved portion, 
 
       wherein:
 the splitter wall ring portion is cylindrical and comprises an outer surface parallel to the axis of rotation; and/or 
 the splitter wall curved portion comprises an outer surface which is concave. 
 
     
     
         15 . The road cleaning machine of  claim 14  wherein
 the splitter wall ring portion extends from the splitter wall aperture to the splitter wall curved portion, and/or 
 the splitter wall curved portion extends from the splitter wall ring portion to the splitter wall main body. 
 
     
     
         16 . The road cleaning machine of  claim 12  wherein the blades extend to adjacent to the splitter wall guide wall or extend at least partially across the splitter wall guide wall. 
     
     
         17 . The road cleaning machine of  claim 1  further comprising an inlet duct wherein the fan casing inlet is in fluid communication with the inlet duct. 
     
     
         18 . The road cleaning machine of  claim 17  further comprising a fluid guide vane disposed in the inlet duct and configured to direct fluid into the impeller in a direction parallel to the axis of rotation of the centrifugal fan assembly. 
     
     
         19 . The road cleaning machine of  claim 18  wherein:
 the inlet duct is elongate along a duct longitudinal axis wherein the duct longitudinal axis is nonparallel to the axis of rotation of the centrifugal fan assembly; and 
 the fluid guide vane comprises a first vane portion extending parallel to the duct longitudinal axis from a first vane end and a second vane portion extending parallel to the axis of rotation from a second vane end. 
 
     
     
         20 . A method of operating a road cleaning machine wherein the road cleaning machine comprises:
 a fan casing comprising a casing inlet and a casing outlet;   an impeller mounted in the fan casing and rotatable about an axis of rotation for drawing fluid from the casing inlet and directing the fluid to the casing outlet, the impeller comprising:
 a splitter wall extending outwardly from the axis of rotation to define first and second blade chambers extending from first and second faces of the splitter wall respectively, wherein the splitter wall comprises a splitter wall aperture; and 
 a plurality of blades mounted in the first and second blade chambers, 
   wherein the method comprises:   rotating the impeller about the axis of rotation such that fluid is directed from the casing inlet, through the first and second blade chambers to the casing outlet and the fluid is directed into the second blade chamber via the splitter wall central aperture.