GB2287418A

GB2287418A - Filter arrangement

Info

Publication number: GB2287418A
Application number: GB9404424A
Authority: GB
Inventors: Peter Alexander Claren Munnoch
Original assignee: Applied Sweepers Ltd
Current assignee: Applied Sweepers Ltd
Priority date: 1994-03-08
Filing date: 1994-03-08
Publication date: 1995-09-20
Anticipated expiration: 2014-03-08
Also published as: GB2287418B; GB9404424D0

Abstract

A suction sweeping machine (10) includes a filter arrangement (12) for collecting debris from a fluid stream. The filter arrangement comprises an outlet (28) leading into the filter arrangement (12), a container, in the form of a plastic bag, for collecting debris and having an open upper end, and a porous tube (30) which extends downwardly into the bag (32). The arrangement is such that a debris carrying fluid stream flowing from the outlet diffuses through the porous tube and out of the open end of the bag, while the debris remains within the bag. <IMAGE>

Description

FILTER ARRANGEMENT This invention relates to a filter arrangement for collecting debris from a fluid stream, and in particular, but not exclusively, to the filter arrangement of a suction sweeping machine.

One-man operated suction sweeping machines, such as the Green Machine (RTM) supplied by Applied Sweepers of Falkirk, Scotland, are becoming increasingly popular for use in the cleaning of pedestrian areas. Such machines include a suction inlet at ground level, through which debris is drawn and then collected in a large capacity bag or sack. In the Green Machine suction sweeping machine mentioned above, the larger debris is collected in a 70 litre woven polypropylene bag, which itself is contained within a 215 litre terylene outer filter bag, in which any fine dust or dirt not collected in the internal bag is trapped. The machine is provided with water mist dust suppress ion which assists in containing dust particles within the internal bag. However, when an operator has to remove a filled internal bag, the bag is likely to be wet and dirty and it may prove difficult for the operator to remove the bag from the machine for disposal without soiling the machine and his own hands and clothing. In machines which are not provided with dust suppression systems, dust may spill through the internal bag while it is being removed from the machine, and dust will tend to collect within the outer bag, which dust will spill out when the outer bag is opened to gain access to the internal bag.

In addition, the disposable porous internal bags are relatively expensive and represent a significant proportion of the running costs of such a machine.

It is among the objects of the present invention to provide a filter arrangement suitable for use in a suction sweeping machine which is more convenient than conventional arrangements.

According to the present invention there is provided a filter arrangement for collection debris from a fluid stream, the arrangement comprising: an outlet; a container for collecting debris and having an opening in an upper portion thereof; and a porous member extending between the outlet and the container opening, the arrangement being such that a debris-carrying fluid stream flowing from the outlet may diffuse through the porous member and out of the opening, while the debris remains within the container.

The invention also relates to a suction sweeping machine including such a filter arrangement, such that, in use, the fluid stream flowing from the outlet may carry papers, drinks cans, cigarette ends and the like. This bulky debris will collect in the container which may be periodically emptied or removed for disposal. Also, when used in a machine provided with water mist dust suppression, the "wet" dust and dirt will remain in the container and may thus be easily and cleanly removed from the machine. Similarly, when the suction sweeping machine passes over a puddle, the water drawn into the machine will be retained in the container and will not result in the machine leaving a trail of dirty water behind it as occurs with conventional arrangements, as the water drains from the porous bag.

The container may be a rigid or semi-rigid box but is preferably in the form of a sack or bag. In the majority of applications a simple plastic bin bag" or "bin liner" will suffice, such that filled bags may be readily removed, sealed and disposed of, and a supply of replacement bags may be carried on the machine. The ability to use such bags also reduces the running costs of the machine; these bags are relatively inexpensive and available from a wide variety of sources. The bag may be located within a bucket or box which provides protection for the bag and improves the appearance of the machine.

Preferably also, the arrangement includes a second filter member, through which the fluid stream flows after exiting the container, to remove fines from the fluid stream which do not remain in the container. In the majority of applications most of the finer dirt and dust will still tend to collect in the container such that replacement or cleaning of the filter member will only be required relatively infrequently. The filter member may be in the form of a large porous bag which is periodically emptied or replaced. Alternatively, the filter member may form a wall of an enclosure in which the container is located or an end wall of a conduit, and may be adapted for periodic replacement or cleaning. Most preferably, the container is replaceable without disturbing the filter member.

Preferably also, the porous member is tubular and extends into the container. Most preferably, the tubular porous member is open at the end spaced from the outlet, to facilitate removal of debris with the container.

Preferably also, the tubular porous member extends to the base of the container. Most preferably, the porous member and the container are arranged such that a gap is maintained therebetween, to facilitate airflow through a large area of the member. Most preferably, the porous member is frustoconical or flared, and widens from the outlet towards the base of the container.

The porous member may be formed of flexible material, for example woven polypropylene, or may be rigid, for example formed of a metal mesh. A single porous member may be provided. Alternatively, two or more porous members, of successively finer pore size, may be provided such that larger debris is retained in the container by the first porous member, while finer particles are retained by the succeeding members. In a suction sweeping machine, such an arrangement may obviate the need for an outer bag or a second filter member.

This and other aspects of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a somewhat schematic side view of a suction sweeping machine provided with a filter arrangement in accordance with a first embodiment of the present invention; Figure 2 is a perspective view of the filter arrangement of a suction sweeping machine in accordance with a further embodiment of the present invention; Figure 3 is a perspective view of part of the filter arrangement of Figure 2; Figure 4 is a sectional side view of the parts of Figure 3; Figure 5 is a cut-away perspective view from the rear of a suction sweeping machine including a filter arrangement in accordance with another embodiment of the present invention; and Figure 6 is a somewhat schematic sectional side view of the filter arrangement of Figure 5.

Reference is first made to Figure 1 of the drawings which illustrates a suction sweeping machine 10 including a filter arrangement 12 in accordance with one embodiment of the present invention. The machine 10 is wheel mounted and is operable by a person walking behind the machine and directing the machine by means of handles 14. Power for the machine is provided by a small IC engine 16 which also drives a pair of side brushes 18 to direct dirt, dust and debris into a vacuum intake 20. A conduit 22 leads from the intake 20 to an impeller 24 which, in addition to drawing the air through the intake 20, breaks up any larger debris carried into the machine. From the impeller 24, the debris-carrying airstream is directed through an upwardly and then rearwardly extending conduit 26 the outlet 28 of which leads into the filter arrangement 12.

In communication with the outlet 28 is a porous member in the form of a conical porous tube 30 which extends downwardly into a container in the form of a disposable plastic bag 32. Both the tube 30 and the bag 32 are located within a collection box 34 which is secured to the machine by a clamp arrangement 36. The upper end of the bag 32 is folded over the top of the box 34 and is also held in place by the clamp arrangement 36. A supporting castor 38 is mounted on the base of the box 34 and some movement of the box relative to the rest of the machine 10 is permitted by the flexible bellows section 40 which forms the upper part of the box 34 and by a pair of pivotable links 42 which secure the lower end of the box relative to the machine 10.

Within the box 34, the tube 30 and plastic bag 32 are arranged such that an annular gap 44 is maintained between the tube and bag. Thus, air may flow downwardly into the tube 30, change direction and dissipate through the tube wall into the gap 44, and then flow out of the open end of the bag 32 through an annular space around the outlet 28.

The majority of dust, dirt and debris carried by the incoming airstream does not pass through the wall of the tube 30 and will therefore gather in the lower end of the tube 30 within the bag 32. Any remaining fines carried by the airstream are trapped by a filter member 46 provided in a filter box 48 at the rear of the machine.

If the machine 10 is provided with water mist dust suppress ion the water droplets will also be collected within the tube 30 and thus within the bag 32.

Once the tube 30 is filled with debris the operator simply releases the clamp 36, tilts the box 34 to the side, pulls the tube 30 out of the bag 32, and then lifts the bag 32 from the collection box 34. The bag 32 may then be tied and left for collection and disposal. A new bag is then placed in the box 34, the upper end of the bag folded over the top of the box 34, the tube 30 placed in the bag 32 and the box and bag 34, 32 secured to the machine with the clamp 36.

As the majority of dust and dirt picked up by the machine 10 does not pass through the tube wall, the filter member is likely to require only infrequent replacement or cleaning, typically on a daily basis.

Reference is now made to Figures 2, 3 and 4 of the drawings which illustrate a filter arrangement 60 in accordance with a further embodiment of the present invention, also for use in a suction sweeping machine as described above. The filter arrangement 60 is provided within a housing 62 for location at the rear of the suction sweeper machine and includes an upper portion 64 containing a right angle conduit 65 for communication with the outlet of the duct leading from the impeller of the machine. The conduit 65 terminates at a diaphragm panel 68 which includes a square peripheral frame 70 and a central circular frame portion 72 which engages the end of the conduit 65. A porous sock 74 is mounted on the inner portion 76 of a circular frame 78 provided below the panel 68 and forms a continuation of the conduit 65. The frame 78 is mounted to the diaphragm panel 68 and a seal is formed between the outer edges of the frame and panel 78, 68. The sock 74 extends into a plastic sack 80 which is itself located within a rectangular box 82. The sack 80 is supported by a sack carrier frame 84, the top of the sack 80 being folded over the frame 84 and held on the frame 84 by the circular frame 78, which includes a circumferential wall 79 sized to provide a friction fit with the sack carrier frame 84 and thus clamp the sack 80 on the frame 84. The frame 84 is mounted on a pair of guides 86, 87.

In a similar manner to the above described embodiment, a debris-carrying airstream passes through the conduit 65 and downwardly into the open end of the sock 74, the air then dissipating through the sock leaving the debris trapped inside. The air then passes upwardly through annular spaces 77 between the inner frame portion 76 and the circular peripheral frame 78 and through spaces 71 in the panel 68 into the upper portion 64 of the housing. The air exits the housing through a large area filter member 88.

As with the first described embodiment, a filled plastic sack 80 may be easily removed from the housing 62 and replaced with an empty sack, the filter member 88 requiring replacement or cleaning substantially less frequently.

Reference is now made to Figures 5 and 6 of the drawings which illustrate a slightly different suction sweeping machine 100 provided with a filter arrangement 102 in accordance with another aspect of the present invention. As in the previously described embodiments, debris-carrying air is blown from a conduit or duct 104 downwardly into a conical porous open-ended sock 106 located in a rear portion of the machine 100. The sock 106 extends into an open-topped rectangular container 108 lined with a plastic bag 110. The contained 108 sits in a housing 112, access to which is gained through a door 114 provided with a filter 116.

In use, the larger debris in the airstream exiting the duct 104 is trapped inside the sock 106, the filtered air passing through the sock 106, out of the container 108 and then through the filter 116, where any remaining dust or dirt in the airstream is trapped. When the sock 106 has become filled with debris, the machine is switched off and the door 114 opened, such that the container 108 may be removed from the housing 112. As the container 108 is removed the debris falls from the sock 106 into the container 108 and the debris filled bag 110 is then lifted from the container 108 for disposal.

Another bag may be located in the container 108, which is then repositioned in the housing 112, with the sock extending into the container 108, and the door 114 closed.

It will be apparent to those of skill in the art that the above-described embodiments of the present invention obviate the need for a porous internal bag and also allow replacement of the internal bag or sack without disturbing the filter member.

It will also be apparent to those of skill in the art that the above-described embodiments are merely exemplary of the present invention and that various modifications and improvements may be made thereto without departing from the scope of the invention, for example: the filter arrangement may include a conventional porous outer bag surrounding the plastic bag, in place of the rigid containers and filter members disclosed above.

Claims

1. A filter arrangement for collecting debris from a fluid stream, the arrangement comprising: an outlet; a container for collecting debris and having an opening in an upper portion thereof; and a porous member extending between the outlet and container open, the arrangement being such that a debris-carrying fluid stream flowing from the outlet may diffuse through the porous member and out of the opening, while the debris remains within the container.

2. The filter arrangement of claim 1 wherein the container is a rigid or semi-rigid box.

3. The filter arrangement of claim 1 wherein the container is in the form of a sack or bag.

4. The filter arrangement of claim 1, 2 or 3 including a second filter member, through which the fluid stream flows after exiting the container.

5. The filter arrangement of claim 4 wherein the second filter member is in the form of a large porous bag.

6. The filter arrangement of claim 4 wherein the second filter member forms a wall of an enclosure in which the container is located.

7. The filter arrangement of claim 6 wherein the container is replaceable without disturbing the second filter member.

8. The filter arrangement of any one of the preceding claims where the porous member is tubular and extends into the container.

9. The filter arrangement of claim 8 wherein the tubular porous member is open at the end spaced from the outlet.

10. The filter arrangement of claim 8 or 9 wherein the tubular porous member extends to the base of the container.

11. The filter arrangement of claim 10 wherein the porous member and the container are arranged such that a gap is maintained therebetween, to facilitate airflow through a large area of the member.

12. The filter arrangement of any one of claims 8 through 11 wherein the porous member is frustoconical or flared, and widens from the outlet towards the base of the container.