Cleaning vehicles

Abstract: A vehicle comprises brush gear (24), a duct (36), a chamber (38) and suction means (164,166) connected to said chamber (38). The suction means (164,166) discharges the screened air from the chamber (38) through the screening means (192) to a diffuser duct (174).

Description: This invention relates to cleaning vehicles comprising matter removal means such as brush gear or suction gear , or both. There is disclosed in DE 925,777 a self-propelled cleaning vehicle in accordance with the pre-characterising portion of claim 1 hereof in the form of road sweeping apparatus wherein the suction side of the suction means is connected to the material receptor tank or chamber through screening means for removing large particles from the air stream. The pressure side of the suction means or fan discharges through screen or filter means located above the material receptor tank for removing smaller particles before discharge to atmosphere. In the illustrated embodiments, the suction means or fan appears to be mounted on a support structure having, in one view, an upwardly tapering form provided, presumably, with a view to maximising the stability of the structure by means of the wider base thereby available. Another example of such a vehicle is a self-propelled cleaning vehicle for cleaning roads and/or runways and/or pavements and/or carrying out industrial cleaning and sweeping , the vehicle having suction gear including a suction nozzle with brush gear in the form of side brushes rotating about upwardly extending axes and serving to sweep matter laterally inwardly into the path of the nozzle. Presently available cleaning vehicles require improvement in respect of the brush gear and suction gear and associated assemblies , particularly their structure , mounting and control. As regards the suction gear , improvements are also needed in respect of the ducts and other assemblies , particularly their structure and arrangement having regard to air flow , power consumption and related factors . An object of the invention is to provide cleaning vehicles , and other apparatus , providing improvements in one or more of these respects ,or generally. According to the invention there is provided a cleaning vehicle as defined in the accompanying claims . Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which : Fig 1 shows a perspective view of a cleaning vehicle as seen from the rear and one side , with the vacuum tank shown raised to its rear discharge position for emptying into a skip or the like , the steering gear and nozzle being shown turned for a right hand corner ; Fig 2 shows a perspective view of the suction gear including the fan assembly of the vehicle of Fig 1 , the direction of viewing being indicated , approximately by arrow XIV in Fig 1 , this figure also showing , diagrammatically , the positions and approximate dimensions of two plenum chambers , and two vacuum chambers which co-operate with the ducts seen in Fig 2 ; Fig 3 shows an exploded view of one of the fan assemblies seen in Fig 2 ; Fig 4 shows a rear view of part of the vacuum tank assembly of Fig 1 , the direction of viewing being indicated by arrow XVI in Fig 1 ; SUCTION GEAR - FAN ASSEMBLY AND VACUUM TANK Previously proposed suction cleaning vehicles employ fans driven by mechanical or hydraulic means from an internal combustion engine. Where an auxiliary engine is provided to drive the fan , substantial energy losses can be accommodated , but this is not the case with the compact vehicle described below in which a single power plant must drive all systems of the vehicle and with maximum efficiency . Therefore , in such a vehicle , the typical fan operating efficiency of 40% or less for conversion of power imput to air pressure and flow cannot be accepted. Other unsatisfactory aspects of presently available sweeper vehicles include high noise output from the pressure side of the ban and from the entry to the nozzle , and the significant space taken up by air transfer ducts and chambers and the consequential effect on overall vehicle size. As shown in Figs 1 to 4 of the drawings , vehicle 10 comprises a rear engine 160 driving hydraulic pumps delivering fluid to hydraulic motors driving rear wheels 18 and corresponding hydraulic motors 162 driving respective fan assemblies 164 and 166 . The fans constitute suction means communicating on their suction sides through suction ducts 168 and 170 with vacuum tank 38 whereby air and matter are drawn via the nozzle suction duct 36 , into the tank. The pressure side of each fan discharges air to atmosphere through respective diffuser ducts 172 and 174 which have duct walls which diverge towards the outlet end thereof . The diffuser ducts discharge the air from the pressure side of the fans through respective plenum chambers 176 and 178 provided on an upper portion of tank 38 at the front end thereof. The plenum chambers are formed as an integral moulded assembly with two other generally wedge-shaped chambers , namely suction chambers 180,182. Between plenum chambers 176 and 178 is a central channel 184 having a generally horizontal top surface 186 forming a forward continuation of the flat rear surface 188 of vacuum tank 38 which , as shown in Fig 1 , pivots to an open discharge position when tank 38 is raised for emptying . The various chambers and channels are indicated diagrammatically in Fig. 2 and are formed in a unitary plastics moulding 190 secured into the too of vacuum tank 38 . Suction ducts 168 and 170 open through suction chambers 180 and 182 and through inclined wire mesh screens 192 into vacuum tank 38. Thus the relatively large rectangular screens constitute the means through which the tank is evacuated . The arrows 194 indicate air passing through the screens and into the suction ducts . Arrow 196 indicates air and entrained matter leaving the discharge end 130 of the nozzle suction tube 36 . Arrows 198 show air discharged from the pressure side of fans 164 and 166 . The upper ends of diffuser ducts 172 and 174 mate with inlet openings 197 , 195 formed in plenum chambers 176 and 178 . The front and rear walls 193 , 191 of the plenum chambers diverge , whereby the fore/aft width of the chambers progressively increases in the discharge direction. A generally horizontal screen 189 , 187 is provided at the top of each chamber 176 , 178 and closes the top opening thereof , extending between the edges defining the opening . The screen comprises wire mesh or expanded metal material and serves further to decelerate air discharged . In use , the plenum chambers represent a considerable enlargement of the cross-sectional area of the diffuser ducts and serve to decelerate the air discharged into them , and this effect is increased by the top screens. As shown in Fig 3 , fan assembly 166 comprises a bladed impeller 185 rotated by hydraulic motor 162 about a lateral axis 183 within a housing formed by an annular duct 181 blending with diffuser duct 174 , together with a rear plate 179 and a front plate 177 having a central inlet opening connected to suction duct 170. Fig 3 shows the detail of the duct walls . In Fig 2 , these are shown encased in plastic sound absorbent material and are not seen so well. The diffuser duct is quadrilateral in cross-sectional shape and generally rectangular . One or both pairs of the duct walls may diverge. In this embodiment front and rear walls 175 , 173 diverge more rapidly than side walls 171A, 169A. Where one pair of walls diverges and one pair are parallel , the included angle between the diverging walls preferably lies in the range of 5 degrees to 20 degrees , and 10 degrees to 12 degrees being the preferred range , with 11 degrees the optimum angle. Where all four sides are divergent , the included angle between opposite sides may be from 3 degrees to 15 degrees , preferably 5 degrees to 8 degrees and ideally 6 degrees . It will be noted that fans 164 and 166 are positioned at a relatively low location so that the diffuser ducts 172 and 174 have sufficient length for non-turbulent reduction of air velocity . For example , with a fan outlet air velocity of about a 130 kilometres per hour it has been possible to attain a reduction of air velocity to approximately 8 kilometres per hour at the discharge from the plenum chambers , in a distance of about 60 centimetres , in this embodiment. Preferably , a diffuser duct length of at least 30 centimetres is provided . In use , fans 164 , 166 evacuate tank 38 via suction ducts 168 , 172 and suction chambers 180, 182 which are closed at their tops 171 , 169 and open rearwardly through screens 192 into the tank. The pressure drop in the tank causes air inlet thereto via nozzle 30 and suction duct 36 . Entrained matter hits top surface 186 of the tank and is deposited therein . The pressure sides of the fans discharge through diffuser ducts 172 , 174 which permit efficient conversion of air kinetic energy to pressure and volume flow energy without turbulence, whereby also the efficiency of conversion of fan energy to air flow energy is significantly enhanced. Efficient deposition of matter within the tank and avoidance of undue dust discharge through the plenum chambers is promoted by use of a water spray from a water tank 167 to a spraynozzle (not shown) in front of nozzle 30 and discharging directly downwards onto the surface to be swept. The water thereby collected in tank 38 is recirculated via a filtering screen , back to the tank. The tank has a lower most portion with adjacently downwardly sloping walls from which portion the recirculated liquid is drawn . The tank includes a separate clean water compartment feeding water to nozzles on the brush gear.

Claims: A self-propelled cleaning vehicle ( 10 ) comprising : a chamber ( 38 ) to receive matter removed in a cleaning operation ; brush gear and matter inlet means (30 ) positionable in working relationship to a surface to be cleaned , to remove matter therefrom ; a duct ( 36 ) connecting said chamber with said inlet means ; and suction means ( 164,166 ) having its suction side connected to said chamber ( 38 ) through screening means ( 192 ) to draw air from said chamber thereby lowering the pressure therein and causing air and matter to be drawn through said inlet means and through said duct and into said chamber where the matter is deposited ; characterised in that, in use, the pressure side of said suction means discharges screened air drawn from said chamber (38) through said screening means ( 192 ) to a diffuser duct ( 172,174 ) having duct walls ( 173,175 ) which diverge towards the outlet end thereof , for discharge to atmosphere. A cleaning vehicle according to claim 1 characterised in that the length of said diffuser duct ( 172,174 ) is at least thirty centimetres , the duct being of rectangular cross-sectional shape , all four walls of the duct diverging and the included angle between opposite sides of the duct being from three degrees to fifteen degrees. A cleaning vehicle according to claim 1 characterised in that the length of said diffuser duct ( 172,174 ) is at least thirty centimetres and the duct being of rectangular cross-sectional shape , two walls thereof diverging and the included angle between said diverging sides being from five degrees to twenty degrees .

Inventors: DUNCAN IAN JAMES, DUNCAN, IAN JAMES
Applicants: MORNINGFIELD LTD, MORNINGFIELD LIMITED
Application year: 1986
Main classification: E01H1
IPC codes: E01H1, A47L11