GB2164378A

GB2164378A - Suction nozzles for suction refuse collection vehicles

Info

Publication number: GB2164378A
Application number: GB08522391A
Authority: GB
Inventors: Anthony J Duthie
Original assignee: JOHNSTON ENG Ltd
Current assignee: JOHNSTON ENG Ltd
Priority date: 1984-09-14
Filing date: 1985-09-10
Publication date: 1986-03-19
Also published as: GB8522391D0; GB2164378B; GB8423261D0

Abstract

A suction nozzle for a refuse collecting vehicle has a rectangular housing arranged transversely of the vehicle and mounted on road wheels. The housing has large front and rear inlets for air and debris and a constricted throat which is connected by a conduit to a suction zone of the vehicle. The inlets are arranged so there is a relatively low velocity air stream through them. A brush is rotated at the rear of the nozzle to lift refuse into the air stream. <IMAGE>

Description

SPECIFICATION Suction nozzles for suction refuse collection vehicles This invention relates to suction nozzles for suction refuse collecting vehicles.

Conventionally, suction nozzles rely on a high speed air stream entering a peripheral aperture around a lower edge of the nozzle and especially at ground level to entrain refuse material lying on the ground, thus causing it to become airborne and conveying it in the air stream along a suction conduit to a debris container. The air stream entering this peripheral gap needs to be of tornado or hurricane force (more than 200 kph) to work satisfactorily.

For this reason, prior art nozzles of this kind have generally been arranged very close to the ground. Examples of such nozzles are shown in British Patents 486505, 1446349. Such nozzles have sometimes had brushes associated therewith, the purpose of the brushes being to move debris into the path of the nozzle. An example of this is shown in British Patent Application 2126633A. Figure 1 shows a further example of a nozzle 1 of this type in cross-sectional side elevation. The nozzle comprises a housing 2 of generally rectangular crosssection formed with a constricted throat 4 leading to a flexible suction conduit 3. The housing is pivotally mounted at 6 on a towing support 7 which is pivotally mounted, in use, to a refuse collecting vehicle by a pivot 8. The nozzle runs on ground wheels 9 rotatably mounted to the support 7.

This nozzle has various disadvantages arising from the fact that the peripheral aperture between the nozzle and the ground must be small so as to ensure a high speed air stream sufficient to entrain the refuse material 5 lying on the ground. At the front of the nozzle the gap 10 is typically 40 mm high while the rear gap 11 is typically 10 mm high.

Thus in this normal operational position it is not possible for large objects of refuse to enter the nozzle. To allow such entry, the housing 2 can tilt about the pivot 6 but this results in the air speed falling and some materials such as small stones can be left behind. Another limitation is that at faster sweeping speeds material can be left behind due to the short duration of time in which the air stream acts on refuse particles, so that there is not enough time for the particles to become airborne.

The- use of a rotary brush has been proposed in the past to assist lifting refuse material off the ground but this has always been as an additional aid to the high speed air stream.

A further prior art arrangement is shown in British Patent 1184795. In this arrangement, a rectangular nozzle is arranged with the long sides in the direction of travel so that debris is within the nozzle for a longer period. A brush is provided to assist in sweeping debris into the air stream within the nozzle and this brush is shrouded by a rear wall of the nozzle housing to ensure that there is still a high speed around the brush.

All the above described prior art arrangements have relied on a very high speed air stream to entrain the particles of debris. A very significant disadvantage of the known nozzles as described above is that the required high speed air stream is very turbulent in its flow and is consequently extremely noisy. We have found in recent investigations that the noise produced by such an air stream can be more than 50% of the total sound power generated by the entire refuse collecting vehicle.

The invention provides a suction nozzle for a suction refuse collecting vehicle, the nozzle comprising a housing having an opening which in use is downwardly facing and above the ground, a substantial front (in use) inlet for ingress of refuse material and air, a throat leading to a suction outlet for connection by a suction conduit to a low pressure zone on the vehicle, and a substantial rear air inlet, a brush rotatably mounted at the rear of the housing for sweeping refuse material off the ground and towards the throat while still permitting substantial air flow into the housing through the rear inlet, and means for rotating the brush, the front and rear inlets of the housing being sufficiently large to provide a low velocity of air flowing therethrough into the housing thereby to reduce the noise emission from the nozzle.

Preferably, the brush is rotatably mounted on a support which itself is freely pivotably mounted in such a way that as the brush wears, the support pivots relative to the housing to maintain the brush in contact with the ground.

As the brush wears, the arrangements may be such that it permits progressively greater flow of air into the housing through the rear air inlet.

The housing may be rectangular in plan view and arranged transversely of the vehicle.

The nozzle may further comprise road wheels for the housing and means pivotally connecting the nozzle to the vehicle to allow up and down movement of the nozzle in relation to the vehicle.

Preferably the front and rear inlets are defined by streamlined edge portions of the housing.

An embodiment of the invention will now be described, by way of example, with reference to Figures 2 to 4 of the accompanying drawings, in which Figure 2 is a general perspective view of a nozzle embodying the invention; Figure 3 is a schematic cross sectional side elevation of the nozzle of Figure 2; and Figure 4 is a diagramatic plan view showing the nozzle mounted on a refuse collecting vehicle.

The nozzle 20 of the invention comprises a housing 22 formed with a throat 24 leading to a suction outlet 21 connected by a flexible suction conduit 23 to a low pressure zone on a refuse collecting vehicle. The housing is generally rectangular in plan view and is supported on two ground wheels 29 rotatably mounted on opposite (shorter) edges of the housing. It is towed by a linkage 27 pivotably mounted between the housing at 26 and the vehicle at 28. A ram (not shown in the drawings) is pivoted to the housing at 37 and to the vehicle to absorb shock loads and allow the nozzle to "float" relative to the vehicle. The housing 22 has a substantial front inlet 35 for the ingress of both refuse material 25 and air. This inlet is considerably larger than the front gap 10 of the prior nozzle 1, having height above ground of about 80 mm.This is sufficiently large for a low velocity of air flowing through the inlet 35. The housing 22 also has 3 very substantial rear air inlet 19 adjacent to which is mounted a rotary brush 30 at the rear of the housing.

As can be seen in Figure 3, both front and rear inlets are delineated by edge portions 38, 39 respectively of the housing which are upturned and streamlined. The brush 30 is rotatably mounted on a support 31 and is driven to rotate by a hydraulic motor 32. The support 31 is freely pivoted on either side at 33 to the housing 22 so that as the brush 30 wears (the brush is shown in a worn condition in ghost lines in Figure 3) the support with brush can pivot on the housing as shown by the arc 18 of Figure 3 thus automatically maintaining the brush in contact with the ground. Whatever the state of wear of the brush 30, there is always a substantial aperture 17 between the brush and the housing to permit substantial air flow into the housing through the inlet 19.

The front inlet 35 and the rear inlet 19 are together sufficiently large that the velocity of the air flowing into the housing is low, i.e. insufficient to cause significant lift off of refuse material from the ground. However, because of the constricted throat 24, the air accelerates in the housing to a velocity sufficient to entrain the refuse material. The brush provides the necessary lift off of material from the ground, sweeping it towards the throat and therefore into the high velocity air stream which then carries the material on through the conduit 23.

The low velocity of air stream through the inlets 35 and 19 results in a very considerable reduction of noise emission as compared with previous suction nozzles (such as the nozzle 1) which rely on higher velocity air streams on entry to the nozzle, The noise level is still further reduced by the streamlining of the front and rear inlets.

The nozzle 20 is shown mounted in use on a refuse collecting vehicle 40 in Figure 4. The vehicle is mounted on road wheels 45 and carries a wide roller brush 41 to urge refuse material into a windrow of material 25 for entering the nozzle 20. A vertical channel brush 42 is provided for sweeping gutters and this brush defines the other side of the windrow of material 25. The nozzle 20 is mounted transversely of the vehicle with the brush 30 at the rear as shown in Figure 4.

Claims

1. A suction nozzle for a suction refuse collecting vehicle, the nozzle comprising a housing having an opening which in use is downwardly facing and above the ground, a substantial front (in use) inlet for ingress of refuse material and air, a throat leading to a suction outlet for connection by a suction conduit to a low pressure zone on the vehicle, and a substantial rear air inlet, a brush rotatably mounted at the rear of the housing for sweeping refuse material off the ground and towards the throat while still permitting substantial air flow into the housing through the rear inlet, and means for rotating the brush, the front and rear inlets of the housing being sufficiently large to provide a low velocity of air flowing therethrough into the housing thereby to reduce the noise emission from the nozzle.

2. A nozzle as claimed in Claim 1 wherein the brush is rotatably mounted on a support which itself is freely pivotably mounted in such a way that as the brush wears, the support pivots relative to the housing to maintain, the brush in contact with the ground.

3. A nozzle as claimed in either preceding claim wherein as the brush wears it permits progressively greater flow of air into the housing through the rear air inlet.

4. A nozzle as claimed in any one of the preceding claims in which the housing is generally rectangular in plan view and arranged transversely of the vehicle.

5. A nozzle as claimed in any one of the preceding claims further comprising road wheels for the housing and means pivotably connecting the nozzle to the vehicle to allow up and down movement of the nozzle relation to the vehicle.

6. A nozzle as claimed in any one of the preceding claims in which the front and rear inlets are defined by streamlined edge portions of the housing.

7. A suction nozzle for a suction refuse collecting vehicle and substantially as hereinbefore described with reference to and as shown in Figures 2 to 4 of the accompanying drawings.