GB2457689A

GB2457689A - Suction Recycling Arrangement

Info

Publication number: GB2457689A
Application number: GB0803164A
Authority: GB
Inventors: Edward Richard Twell; Mark Richard Vines
Original assignee: Balfour Beatty PLC
Current assignee: Balfour Beatty PLC
Priority date: 2008-02-21
Filing date: 2008-02-21
Publication date: 2009-08-26
Also published as: GB0803164D0; WO2009104009A1

Abstract

A suction recycling arrangement 3 for use in processing and recycling excavated material. The arrangement comprises: a suction generating unit 5 arranged to generate a high velocity airflow suction; and an enclosed mixing chamber 7 for mixing the excavated material and a stabilizing agent, the chamber having a suction port 17 externally coupled to the suction generating unit 5 and a first inlet port 21 for receiving the excavated material. The chamber is arranged so that the suction received at the suction port 17 is transmitted to the first inlet port 21, but the excavated material received at the first inlet port 21 is substantially prevented from being transmitted to the suction generating unit. This can be achieved with shields (25, 27, fig 3). The arrangement may be provided on a vehicle.

Description

I

Suction RecyclinQ Arranciement This invention relates to a suction recycling arrangement, particularly for use in the processing and recyding of raw excavated material (spoil) from civil groundworks.

Excavated material from groundworks often needs to be reinstated, for example where a public right of way has been excavated to obtain access to utility Infrastructure. The excavated material may have been excavated manually or using assisted techniques, such as using a known mechanical excavator or high velocity suction system.

In many situations, the excavated material is substituted by newly prepared material such as graded aggregates, which are known to provide a stable surface and on which, for example, hard surfacing may be reinstated.

However, a problem associated with substituting excavated material with newly prepared material is the significant cost, which includes costs for preparing the replacement material, transporting the materials to and from the groundworks site, and disposing of the potentially unstable excavated material.

It is known to address this problem by reinstating the original excavated material, but with an added stabilising agent which serves to prevent instability of the reinstated material and allow for the subsequent reinstatement of hard surfacing. This avoids the above described costs, but the on-site requirement for mixing the excavated material with the stabilising agent in a controlled matter can itself be problematic.

According to the invention there is provided a suction recycling arrangement for use in processing and recycling excavated material, the arrangement comprising: a suction generating unit arranged to generate a high velocity airflow suction; and an enclosed mixing chamber for mixing the excavated material and a stabilizing agent, the chamber having a suction port externally coupled to the suction generating unit and a first inlet port for receiving the excavated material, wherein the chamber is arranged so that the suction received at the suction port is transmitted to the first inlet port, but the excavated material received at the first inlet port Is substantially prevented from being transmitted to the suction generating unit.

The invention conveniently provides a facility for mixing the excavated matenal with a stabilizing agent, such as a cement-based material. The suction generating unit not only draws the excavated material into a mixing chamber, but also provides for very effective mixing by reason of the air flow in the chamber.

The invention avoids the need for excavated material to be substituted with newly prepared material by facilitating the mixing of the excavated material with the stabilizing agent, which allows for recycling of the excavated material.

Furthermore, difficulties associated with mixing the excavated material and the stabilizing agent on site are avoided.

A shielding arrangement may be provided inside the chamber between the first inlet port and the suction port for preventing the transmission of excavated material therebetween. In alternative embodiments, an arrangement of filters may be provided, but these typically require maintenance and periodic replacement and are therefore less preferred.

The suction port may be provided in a top surface of the chamber and the first inlet port is provided in a side surface of the chamber. In this way, gravity may assist in preventing the excavated material from being transmitted between the first inlet port and the suction port. If the chamber has a circular cross section, one or both of the suction port and the first inlet may be provided substantially tangentially to the chamber to thereby promote cyclonic air movement within the chamber.

The shielding arrangement may comprise a frusto-conical or frusto-pyramidal shield arranged coaxially around the suction port on an internal surface of the chamber. A cross sectional area of the shield preferably increases towards the chamber surface. In this way, large particles of the excavated material may be physically prevented from approaching the suction port, from where they could be drawn into the suction generating unit.

The shielding arrangement may further comprises a secondary shield arranged coaxially around the frusto-conical or frusto-pyramidal shield, the shields together defining a void therebetween, a radial width of the void increasing away from the chamber surface. If the first inlet port is then arranged to face the secondary shield, the excavated material is prevented from entering Into the frusto-conical or frusto-pyramidal shield.

The secondary shield preferably has the same cross sectional shape as the frusto-conical or frusto-pyramidal shield.

The suction port and the first inlet port may be provided in a removable lid of the chamber. In this way, convenient access to the chamber is provided for inspection, cleaning and maintenance.

The chamber may be provided with drivable mixing paddles for mixing the excavated material and the stabilizing agent. In this way, the contents of the chamber may be more efficiently mixed.

The chamber may have a second inlet port for receiving the stabilizing material, and a stabilizing material reservoir may then be coupled to the second inlet port of the chamber. Similarly, the chamber may have a third inlet port for receiving water, and a water reservoir may then be coupled to the third inlet port of the chamber. These features allow for convenient filling of the chamber with the materials required to process the excavated material for recycling purposes.

The chamber may be provided with an outlet port for discharging excavated material which has been processed, for example to refill groundworks excavations.

The suction recycling arrangement may further comprise at least one load cell for determining a weight of the mixing chamber. Load cells may also be provided for determining the weights of stabilizing material and water reservoirs, if present. In this way, the mixing ratio of the materials may be accurately determined and monitored, and a computer-controlled display may be provided for this purpose.

The chamber may further comprise a screen for grading the excavated material received at the inlet port. In this way, the properties of the recycled material may be controlled, for example to avoid large voids caused by excessively large particle sizes. The screen being arranged to vibrate to prevent clogging.

The suction recycling arrangement may further comprise a suction hose externally coupled to the first inlet port of the chamber for receiving the excavated material by a high velocity airflow suction. In this way, excavated material may be efficiently collected from the site of excavations.

The invention also provides a vehicle, such as a motor vehicle, comprising the suction recycling arrangement described above. The vehicle could be adapted for running on roads or rails. In this way, the arrangement may conveniently be transported between groundworks sites.

The vehicle may be provided with various storage containers for storing excavated material which has been processed. In this way, excavated materials from one site may be recycled at another site.

The invention will now be described in detail, by way of example only, with reference to the accompanying drawings, in which: Figures 1 and 2 are different perspective views of a vehicle carrying a suction recycling arrangement according to the invention; and Figure 3 is a partially cutaway view showing the internal structure of one of the components of the suction recycling arrangement shown in Figures 1 and 2.

The invention provides a suction recycling arrangement for use in processing and recycling excavated material from civil groundworks. The arrangement comprising a suction generating unit arranged to generate a high velocity airflow suction and an enclosed mixing chamber for mixing the excavated material and a stabilizing agent. The chamber has a suction port externally coupled to the suction generating unit and a first inlet port for receiving the excavated material. The chamber Is arranged so that the suction received at the suction port is transmitted to the first inlet port, while the excavated material received at the first inlet port is substantially prevented from being transmitted to the suction generating unit.

The invention also provides a vehicle for carrying the suction recycling arrangement.

Referring to Figures 1 and 2, a vehicle I according to the Invention is provided with a suction recycling arrangement 3. The vehicle I is an ordinary commercial motor vehicle, with the suction recycling arrangement 3 beIng arranged on the vehicle's load bed. The vehicle I provides electrical and hydraulic power for operating the suction recycling arrangement 3. Suitable vehicles I are well known, being available from a number of commercial vehicle manufacturers.

The suction recycling arrangement 3 essentially comprises a suction module 5 externally coupled to an enclosed mixing chamber 7.

The suction module 5 is arranged to generate a high velocity airflow suction at a hose elbow 9. The suction module 5 comprises an electric motor which drives a rotor to generate the suction. A number of air filters are provided to prevent any of the excavated material from damaging the rotor. The suction module 5 is specifically designed for use in systems which collect excavated materials from groundworks excavations, and suitable units are well known in the art.

The mixing chamber 7, the internal construction of which can be seen in Figure 3, is a cylindrical, thin walled vessel. The chamber 7 is provided with a plurality of mixing paddles 11 which are hydraulically driven about an axis of the chamber to mix its contents. The chamber is also provided with a discharge outlet 13 at its base for discharging mixed contents.

The mixing chamber 7 is coupled to the hose elbow 9 of the suction module 5 by a first suction hose 15. The first suction hose 15 is externally attached to a suction port 17 of the chamber 7, which port is arranged axially in a lid 19 of the chamber 7. The lid 19 has a circular cylindrical shape, with a smaller cross sectional area than that of the chamber 7 itself. The lid 19 is provided with a seal for coupling with the body of the chamber 7.

The mixing chamber 7 is also provided with a first inlet port 21. The first inlet port 21 is arranged tangentially in a side wall of the lid 19 such that air and excavated material received at the suction port 17 cause cyclonic flow within the chamber 7, whIch cyclonic flow assists in the mixing process. A second suction hose 23 is externally attached to the first inlet port 21 for directing at and receiving excavated material. The velocity of the airflow at the end of the second suction hose 23 is sufficiently high to lift the excavated material.

The lid 19 of the mixing chamber 7 is provided with a shielding arrangement which allows the suction to be transmitted from the suction port 17 to the first inlet port 21, but which substantially prevents excavated material received at the first inlet port 21 from being transmitted to the suction port 17. The shielding arrangement comprises first and second shields 25, 27 arranged inside the lid 19 of the chamber 7 coaxially with the suction port 17. The first shied 25 has a circular frusto-conical shape, with a diameter which increases towards the suction port 17. The second shield 27 has a circular cylindrical shape, with a cross sectional diameter identical to that of the first shield at its base, which diameter is however smaller than an internal diameter of the lid.

The second shield 27 extends sufficiently into the chamber 7 to cover the first inlet port 21.

The first and second shields 25, 27 together define a void which serves to maintain a separation between the high velocity airflow into the suction port 17 and excavated material entering the chamber 7 at the first inlet port 21. This separation ensures that the excavated material drops into the base of the chamber 7 before it can be entrained in the high velocity airflow in the region of the suction port 17. The first shield 25 also physically prevents any large particles of excavated material from reaching the suction port 17.

The mixing chamber 7 is also provided with second and third inlet ports 29, 31 for adding a stabilizing agent and water from respective reservoirs 33, 35. The stabilizing agent is a solid material and the second inlet port 29 for this material is integrated into the first inlet port 21 for excavated material. Hoses connecting the reservoirs 33, 35 to respective inlet ports are provided with valves.

The suction recycling system 3 additionally comprises load cells (not shown) arranged at the mounting points for the mixing chamber 7. The load cells are coupled to an electronic circuit, which circuit determines a weight of the contents of the chamber 7 and outputs it to a display for use by an operator of the system 3.

In use, excavated material is drawn into the mixing chamber 7 through the second suction hose 23 by the action of the suction module 5 creating a high velocity airflow. A measured quantity of excavated material is obtained using the display of the load cells.

Once the excavated material has been received into the mixing chamber, valves on the hoses coupling the stabilizing material and water reservoirs to the chamber are opened, one at a time. Again, the display of the load cells is used to control the mixing ratio.

The contents of the mixing chamber are mixed by the combined effect of the mixing paddles 11 and the cyclonic air movement, although the lafter can be dispensed with at this stage by switching off the suction module 5. Once the materials are sufficiently mixed, the materials are discharged through the discharge outlet.

The discharged materials may be used to refill groundworks excavations.

Alternatively, the materials may be temporarily stored in storage bins 37 provided on the load bed of the vehicle I for transport to and use at an alternative site.

As will be appreciated, the invention provides a convenient and effective means for processing and recycling excavated materials, whereby problems associated with known means are avoided.

A specific embodiment of the invention has been described above. However, various changes and modifications may be made without departing from the scope of the invention.

For example, the suction recycling arrangement may be provided on other types of vehicle, such as rail vehicles.

The mixing chamber may be provided with a screen for preventing excessively large particles of excavated material from falling into the base of the chamber.

In this way the particle sizes of the excavated material which is processed can be controlled. The screen may be provided with a vibrating means for preventing clogging.

The mixing process may be undertaken at the same time that excavated material is drawn into the mixing chamber.

Claims

Claims 1. A suction recycling arrangement for use in processing and recycling excavated material, the arrangement comprising: a suction generating unit arranged to generate a high velocity airflow suction; and an enclosed mixing chamber for mixing the excavated material and a stabilizing agent, the chamber having a suction port externally coupled to the suction generating unit and a first inlet port for receiving the excavated material, wherein the chamber is arranged so that the suction received at the suction port is transmitted to the first inlet port, but the excavated material received at the first inlet port Is substantially prevented from being transmitted to the suction generating unit.
2. A suction recycling arrangement according to claim 1, wherein a shielding arrangement is provided inside the chamber between the first inlet port and the suction port for preventing the transmission of excavated material therebetween.
3. A suction recycling arrangement according to claim 2, whereIn the suction port is provided in a top surface of the chamber and the first inlet port is provided In a side surface of the chamber.
4. A suction recycling arrangement according to claim 2 or 3, wherein the shielding arrangement comprises a frusto-conical or frusto-pyramidal shield arranged coaxially around the suction port on an internal surface of the chamber, a cross sectional area of the shield increasing towards the chamber surface.
5. A suction recycling arrangement according to claim 4, wherein the shielding arrangement further comprises a secondary shield arranged coaxially around the frusto-conical or frusto-pyramidal shield, the shields together defining a void therebetween, a radial width of the void increasing away from the chamber surface.
6. A suction recycling arrangement according to claim 5, wherein the first inlet port is arranged to face the secondary shield.
7. A suction recycling arrangement according to any preceding claim, wherein the suction port and the first inlet port are provided in a removable lid of the chamber.
8. A suction recycling arrangement according to any preceding claim, wherein the chamber is provided with drivable mixing paddles for mixing the excavated material and the stabilizing agent.
9. A suction recycling arrangement according to any preceding claim, wherein the chamber has a second inlet port for receiving the stabilizing material.
10. A suction recyding arrangement according to claim 9, further comprising a stabilizing material reservoir coupled to the second inlet port of the chamber.
11. A suction recycling arrangement according to any preceding claim, wherein the chamber has a third inlet port for receiving water.
12. A suction recycling arrangement according to claim 11, further comprising a water reservoir coupled to the third inlet port of the chamber.
13. A suction recycling arrangement according to any preceding claim, wherein the chamber is provided with an outlet port for discharging excavated material which has been processed.
14. A suction recycling arrangement according to any preceding claim, further comprising at least one load cell for determining a weight of the mixing chamber.
15. A suction recycling arrangement according to any preceding claim, wherein the chamber further comprises a screen for grading the excavated material, the screen being arranged to vibrate.
16. A suction recycling arrangement according to any preceding claim, further comprising a suction hose externally coupled to the first inlet port of the chamber for receiving the excavated material by a high velocity airflow suction.
17. A vehide comprising the suction recycling arrangement according to any preceding claim.
18. A vehicle according to claim 17, further comprising a storage container for storing excavated material which has been processed.
19. A suction recyding arrangement or vehicle substantially as hereinbefore described and/or as shown in the accompanying drawings.