GB2270334A

GB2270334A - Pneumatic refuse collection and filter apparatus for a roadsweeper

Info

Publication number: GB2270334A
Application number: GB9310717A
Authority: GB
Inventors: Heinrich Fuss
Original assignee: Kroll Fahrzeugbau Umwelttechnik GmbH
Current assignee: Kroll Fahrzeugbau Umwelttechnik GmbH
Priority date: 1992-09-04
Filing date: 1993-05-25
Publication date: 1994-03-09
Anticipated expiration: 2013-05-25
Also published as: GB9310717D0; IT1270366B; FR2695421B1; ITTO930349A1; DE9212047U1; GB2270334B; FR2695421A1; DE4330233C3; ITTO930349A0; DE4330233C2; DE4330233A1

Abstract

Apparatus for fitting to a roadsweeper which is equipped with pneumatic means for picking up refuse and includes means for the dry pick-up of the refuse and means for separating dust from the conveying air, comprises a filter unit (11) connected with refuse tank (3) by means of a suction socket (9), and wherein a blower (6) is operationally connected with filter unit (11) in such a way that the conveying air taken up by a suction nozzle (1) is first treated in the refuse tank (3) and then separately filtered by means of the fine dust filters arranged in filter unit (11). <IMAGE>

Description

REFUSE COLLECTION AND FILTER APPARATUS FOR A ROADSWEEPER This invention relates to apparatus for fitting to a roadsweeper which is equipped with pneumatic means for picking up refuse and includes means for the dry pick-up of the refuse and means for separating dust from the conveying air.

DE AS 26 32 208 describes a roadsweeper with a tank for collected refuse which is connected to a fine filter and a receiver for the fine dust separate thereby. The receiver for the dangerous fine dust is discharged by opening a connecting flap between the refuse tank and the fine dust receiver so that the fine dust returns to the refuse collector via an appropriately designed inclined chute.

DE PS 26 60 419 describes a discharge device for a roadsweeper in which the connecting flap between the fine dust receiver and the refuse collector is linked with the closure flap for the refuse collector by means of a coupling rod, thus making it possible to open both flaps simultaneously.

Whilst these two specifications disclose separating and separately collecting coarse and fine components of refuse, which are in part toxic and dangerous to health, they suffer from the disadvantage that the two separated components are again mixed in the course of discharge and in particular the fine dust is again discharged in concentrated form into the environment.

Roadsweepers are also known from DE OS 28 41 841, 23 26 241, and DE PS 57 873, which retain, by means of filters, the fine dust components of the refuse which do not sink to the bottom of the refuse collector by gravitation separation. In these devices, the filters are arranged in the refuse collector itself, in its upper zone above the refuse. With these designs, the fine dust components are not collected separately but pass, when the filters are cleaned, immediately into the remaining refuse and discharged jointly.

DE OS 15 07 803 describes a roadsweeper with a mechanical pick-up and conveying system, whereby the air laden with fine dust is drawn off with the aid of a blower. The fine dust components are retained by a filter level downstream of the blower. Although the known technical solutions provide for separate chambers for storing coarse and fine refuse components, they cannot be discharged separately. Thus it is necessary either to discharge the entire refuse collected in a manner corresponding to the dangerous nature of the fine dust components, which entails high costs, or the refuse is discharged in conventional manner irrespective of the dangers posed to persons and the environment.

It is an object of the invention to provide apparatus which enables filtration of the intake air to different degrees of fineness and corresponding collection and treatment of the filtered dust.

According to the invention there is provided a refuse collection and filter apparatus for a roadsweeper comprising pneumatic refuse pick-up means operable for the dry pick-up of refuse and means for separating dust from the conveying air, a refuse tank mounted on the chassis of the vehicle, the pneumatic refuse pick-up means comprising suction nozzle connected by a flexible suction tube which leads into said refuse tank in which there is an overhead baffle, a coarse filter being arranged in the upper part of the refuse tank with an extraction duct leading therefrom, a fine dust filter unit on the vehicle chassis and connected with the extraction duct and separated from the refuse tank, the fine dust filter unit having means for collecting fine dust filtered from the conveying air and being connected with a blower so as to cooperate with the latter.

In a preferred embodiment, a device is provided for collecting and discharging the fine dust.

Advantageously the device for collecting the fine dust is a collecting vessel. The device for discharging the fine dust can be a conveyor screw.

An advantage of the invention is that the refuse and dust are picked up and filtered without the addition of water. It is possible therefore for the roadsweeper to be used continuously in winter at outdoor temperatures below 0 0centigrade.

By arranging the filter casing with the fine filter intalled outside the refuse tank on the vehicle chassis, it is possible to provide for the separate discharge of any environmentally nixous or part toxic fine dust. In conjunction with an efficient discharge device, the device which is arranged on the filter unit for collecting the filtered fine dust ensures straightforward fractional discharge of such extremely fine refuse components when these have been picked up, since the coarse components of the refuse picked up are collected in the refuse tank.

It is now possible to discharge the fine dust and the coarse refuse separately at different times and at different locations. To this end, the device for collecting the fine dust can advantageously be removed from the filter unit and fine dust can be introduced into an appropriate discharge container. The coarse refuse, the volume of which is considerably larger, can be discharged from the refuse tank in known manner at the same time or, if required, later. By virtue of the design arrangement and selection of the filters with their different functions, the entire sweeping device can be used irrespective of th humidity content of the conveying air.

This is an advantage as regards practical operation, since it is possible to achieve fractional discharge of dust not retaining water and of hydroscopic media.

This advantage is due to the fact that, on the one hand no water is used when picking up the refuse, while on the other hand the separately arranged fine filter with its device for self-cleaning of the filter elements makes it straightforward to collect said toxic and hydroscopic media in the collecting vessel.

By arranging the blower on the filter unit, said blower being driven by the engine of the vehicle, there is no need for a separate driving motor for the blower. At the same time, the fact that no separate motor is required for working the blower means that space is advantageously gained for the separate fitting of the filter unit and its arrangement between driver's cab and refuse tank.

Arrangement of the filters upstream of the suction socket of the blower as provided by the invention simplifies in particular the entire system for automatic pick-up and treatment of the refuse taken up in the conveying air.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a side view of an apparatus of the invention; and Figure 2 shows an apparatus similar to that of Figure 1 but with a close-coupled blower.

Referring to the drawings, there is shown in Figure 1 a refuse pick-up and collecting system having a suction nozle 1 connected by a flexible suction tube 2 which protrudes into a refuse tank 3, said tank being equipped with a coarse sieve 4 and an overhead baffle 8. A filter unit 11 and a blower 6 are located in front of the refuse tank 3, these units being arranged on the chassis 7 of the vehicle separately from said refuse tank. Refuse tank 3 is arranged on the chassis 7 so as to be capable of tipping and it serves as a separating chamber and collecting tank for the coarse components of the refuse conveyed by the airstream generated by the blower 6. The overhead baffle 8 in the tank 3 is arranged in the direction in which the refuse is carried by the stream of conveying air, as a result of which the accelerated refuse components are held back and evenly distributed in the refuse tank 3.

The coarse sieve 4 (which may be cylindrical) located in the upper part of refuse tank 3 is connected with an extraction duct 9 for the refuse tank 3, which in the working position is in turn mounted on inlet 10 of filter 5 in such a way as to be positively secured thereto.

The conveying air enriched with relatively fine and extremely fine refuse components flows through intake 10 into an unpurified gas zone 12 of filter 5, filter unit 11 being subdivided into three operational zones namely the aforementioned unpurified gas zone 12, a purified-gas zone 13 and collecting vessel 14 for the fine dust.

The operational zones 12 and 13 are separated by a vertical partition 15 which also accommodates compact filter elements 16 to retain any fine dust components still contained in the air conveying the refuse. The purified conveying air leaves filter 5 via purified-gas zone 13 through an outlet 17.

In the example shown, the outlet 17 is connected with suction socket 18 of the blower 6 by a flexible connecting element 19.

As shown in Figure 2, however, the blower 6 and filter 5 can be close-coupled to form a structural unit in which the outlet of filter 5 is also the suction socket of blower 6. Collecting vessel 14 in the lower part of the filter 5 collects the fine dust components of the refuse conveyed when filter elements 16 are cleaned.

Collecting vessel 14 may be designed in such a way that it can be removed from the filter unit 11, thus making it possible to discharge the fine dust components separately from the remaining refuse.

In the illustrated embodiment, the filter elements 16 are secured in partition 15 horizontally, upright and in juxtaposition, while being also arranged in two rows one above the other. This arrangement enables installation of a particularly large number of filter elements 16, filter unit 11 and filter element 16 allow the conveying air to flow around all sides of the filter elements 16 and to flow through them and over their entire surface, thus ensuring that they are evenly charged with fine dust.

It is essential that the filter elements 16 do not become blocked to ensure continuous operation of the sweeper. To this end, the various filter elements 16 are cyclically cleaned in pairs while work is in progress. In the example illustrated, cleaning is effected without contact using pneumatic cleaning devices 21. With this system, each pair of filters is allocated adjacent a cleaning device 21 which consists of a jet tube 22, with several jets 23 arranged vertically and equidistantly along its length and a control element 24 such as an electromagnetically operated 2/2-way valve. The cleaning devices 21 are so arranged in the purified-gas zone 13 of the filter 5 that the jets 23 face the front of each filter element 16 at a precisely defined distance.

The cleaning effect of filter elements 16 is achieved by blowing compressed air in short bursts onto the surface of the filter elements 16 in a direction opposite to that of the refuse-conveying flow whereby the fine dust deposited in each filter element 16 is removed therefrom and falls downwardly into the vessel 14.

The filter elements 16 are cleaned in sequence, thus ensuring that only one pair of filters is out of action at any one time. The cyclic cleaning process can be controlled by regular time intervals or in accordance with differential pressure by using an electronic control unit (not shown). A roadsweeper fitted with the refuse collecting system of the present invention enables only very pure filtered air to pass through blower 6 into the ambient air.

The described embodiment of the invention enables a roadsweeper to collect the coarse refuse and fine dust filtered therefrom by means of a filter arrangement in separate containers and to discharge them fractionally.

This is achieved by separately arranging on the chassis of the roadsweeper the refuse tank 3 and the filter unit 11 in which fine filters have been fitted, the filter unit 11 being connected with the refuse tank 3 by means of the suction socket 9. The blower 6 is operationally connected with the filter unit 11 in such a way that the conveying air taken up by suction nozzle 1 is first treated in refuse tank 3 and then separately filtered by means of the fine dust filters arranged in filter unit 11.

Claims

1. Refuse collection and filter apparatus for a roadsweeper comprising pneumatic refuse pick-up means operable for the dry pick-up of refuse and means for separating dust from the conveying air, a refuse tank mounted on the chassis of the vehicle, the pneumatic refuse pick-up means comprising a suction nozzle connected by a flexible suction tube which leads into said refuse tank in which there is an overhead baffle, a coarse filter being arranged in the upper part of the refuse tank with an extraction duct leading therefrom, a fine dust filter unit on the vehicle chassis and connected with the extraction duct and separated from the refuse tank, the fine dust filter unit having means for collecting fine dust filtered from the conveying air and being connected with a blower so as to cooperate with the latter.

2. Apparatus according to claim 1 wherein the fine dust filter unit includes means for collecting and discharging the fine dust.

3. Apparatus according to claim 2 wherein the means for collecting the fine dust is a collecting vessel.

4. Apparatus according to claim 2 whereinthe means for discharging the fine dust is a conveyor screw.

5. Apparatus substantially as herein decribed with reference to the accompanying drawings.