WO2008149233A2

WO2008149233A2 - Fan for combines

Info

Publication number: WO2008149233A2
Application number: PCT/IB2008/001902
Authority: WO
Inventors: Brain Jay Hollatz; Eduardo De Oliveira Cristal
Original assignee: Agco Do Brasil Comercio E Indústria Ltda.
Priority date: 2007-06-08
Filing date: 2008-05-19
Publication date: 2008-12-11
Also published as: WO2008149233A3; GB0711032D0; GB2452241A

Abstract

A combine (10) having a fan (25) for separating grain from lighter material in a cleaning section of the combine is provided. The fan comprises an intake housing (45) which is subdivided into two or more separate volumes (45a, 45b, 45c) by one or more baffles (48) which extend within the housing in a direction generally parallel to the direction of induction of air into the housing by the fan. The baffles serve to reduce transverse movements of air within the intake housing.

Description

COMBINES

This invention relates to combine harvesters and in particular to details of fans used in such combines to separate/clean harvested crops.

It is an object of the invention to provide a combine with an improved form of separating/cleaning fan.

Thus according to the present invention there is provided a combine having a fan for separating grain from lighter material in a cleaning section of the combine, the fan having an intake housing which is subdivided into two or more separate volumes by one or more baffles which extend within the housing in a direction generally parallel to the direction of induction of air into the housing by the fan to reduce transverse movements of air within the intake housing.

The present invention is particularly applicable to a combine in which the fan is a cross-flow fan.

The present invention will now be described, by way of example only, with reference to the accompanying drawings in which: -

Figure 1 is a diagrammatic vertical cross-section through a combine harvester embodying the present invention;

Figure 2 is a part-sectional view through a combine cleaning fan in accordance with the present invention;

Figure 3 shows a perspective view of the intake housing of the fan of Figure 2 showing the air flow baffles used;

Figure 4 shows the ends of the impellor of the fan of Figure 2 on a larger scale; Figure 5 shows diagrammatically a recessing arrangement for the ends of the blades of the fan impellor;

Figure 6 shows diagrammatically a non-recessed prior art impellor arrangement for comparison, and

Figure 7 shows diagrammatically in section the fan housing intake and outlet ducts and their positioning relative to the fan impellor.

Referring to the drawings, a combine harvester 10 has a table shown diagrammatically at 11 which includes a cutter mechanism 12 and a feed mechanism which includes an elevator 13 which feeds harvested crop to a thrashing mechanism 14 in the form of a threshing cylinder 15 and a concave 16. Crop exiting from the concave 15 is fed to a beater 17 which feeds the crop towards its centre and hence via a final feed section 18 into an axial separator 19.

The separator 19 comprises a cylindrical housing 20 within which a separating rotor 21 rotates. The rotor 21 has helical flights 21a rotating in the final feed section 18 which move the crop through section 18. The crop is then moved axially through the separator in the annular gap between the housing 20 and the rotor 21. The lower position 22 of separator 19 is a series of grating through which grain, chaff and smaller straw portions etc. fall onto a reciprocating grain pan 23 which transports this material forward until the material cascades from the front end of the pan 23 as shown at 23a into a cleaning mechanism which includes a reciprocating upper sieve 24a, a reciprocating lower finer sieve 24b and an associated transverse cross-flow fan 25. The larger more bulky straw etc. exits from the rear 19a of the separator.

The grain, chaff and straw which passes through the concave 16 is transported towards the sieves 24a and 24b by a belt conveyor 26 which is the subject of the Applicant's corresponding PCT Application No. PCT/EB2006/003906. The conveyor 24 discharges onto a reciprocating grain pan 27 which in turn discharges onto upper sieve 24a with air flows X and Y from fan 25 being used to remove chaff and other material lighter than the grain in the conventional manner. If desired the grain pan 27 can be eliminated completely or can be replaced by a further short belt conveyor.

The grain which passes through the finer lower sieve 24b is collected in the region 28 of the combine for movement into a grain tank on the combine and the tailings (a mixture of partly cleaned/separated grain, chaff and straw) which passes through the upper sieve 24a, but not the lower finer sieve 24b, is collected in the region 29 of the combine from where it is reintroduced into the machine to be reprocessed.

A deflector plate 30 ensures that all the material falling through the concave 15 falls onto the conveyor 26. The conveyor comprises an endless belt 32 which may have raised ridges to aid transport of the material and is supported on two end rollers 33 and 34 which are carried on the combine body.

The present invention is concerned with the design of the transverse cross-flow fan 25.

As can be seen from Figure 2 and 4, the fan 25 has an impellor 40 with a central shaft 41 from which a plurality of generally radially orientated fan blades 42 are supported on discs 43. The shaft 41 rotates about an axis Z which extends generally transversely relative to the combine. The fan has a housing 44 which surrounds the impellor 40 and which has an intake duct 45 and upper and lower outlets ducts 46 and 47 respectively (see Figure 7) which direct the output of the fan along the previously referred to air flows X and Y respectively.

In accordance with the present invention the fan intake duct 45 is provided with generally vertical baffles 48 which divide the duct into separate volumes 45a, 45b and 45c. The provision of baffles 48 prevents and significant transverse movement of air in the intake duct (i.e. prevents significant movement in directions generally parallel to axis Z) which might otherwise lead to a non-uniform intake of air across the length of the impellor. The baffles 48, which extend generally perpendicular to axis Z, ensure that the air is drawn into the intake duct (see arrow I) and hence into and across the impellor housing 44 in a direction generally perpendicular to axis of rotation z of the impellor. This significantly improves the performance of the fan by making the lateral distribution of the existing air more even. As best seen from Figure 4, the shaft 41 is supported from the housing 44 via bearing blocks 49. The axially outer ends of the impellor 40 are supported in recesses 44a and 44b formed in the housing. The axially outermost support discs 43a and 43b of the impellor are positioned so that they are located in the recesses 44a and 44b respectively with the inner faces 43a' and 43b' of the discs are at least flush with the inner surfaces 44c of the adjacent housing. The axially outermost ends 42a and 42b of the blades 42 extend beyond discs 43a and 43b into the recesses 44a and 44b.

As can be send from Figure 5, by recessing the outer support discs 43a and 43b into recesses 44a and 44b the entire width W of the impellor 40 can act as an effective impellor. This contrasts with the arrangement if the impellor is supported in a normal non-recessed manner, see figure 6, when the outer support discs 43a and 43b effectively cut-off the outer ends 42a and 42b of the blades from being an effective part of the impellor, causing dead zones D, so that only the width Wl can be used effectively. The present invention thus provides a significant improvement in impellor efficiency.

Claims

1. A combine having a fan for separating grain from lighter material in a cleaning section of the combine, the fan having an intake housing which is subdivided into two or more separate volumes by one or more baffles which extend within the housing in a direction generally parallel to the direction of induction of air into the housing by the fan to reduce transverse movements of air within the intake housing.

2. A combine according to claim 1 in which the fan is a cross-flow fan.

3. A combine according to claim 1 or 2 in which the fan has an impellor comprising a plurality of blades supported from a central shaft via a number of discs, the blades being attached around the peripheries of the discs and the impellor being rotatable about the central shaft which extends transversely relative to the walls of fan ducting, the ends of the impellor being supported in a recessed manner from the walls of the ducting so that the axially outermost support disc at each end of the central shaft projects into a recess in the wall of the ducting at least as far as the local walls of the fan ducting.

4. A combine according to claim 3 in which the ends of the fan blades extend slightly beyond the axially outermost support discs into the recesses.

5. A combine according to claim 3 or 4 in which the central shaft also extends transversely relative to the associated combine.