GB2040235A - A vessel for disposing of waste at sea - Google Patents

Abstract

A vessel for the disposal of waste at sea, comprises at least one rotatable drum (2) which is adopted both to house the waste and to provide buoyancy for the vessel, means for burning the waste in the or each drum, and means for discharging the waste from the or each drum to the sea. An auxiliary vessel 5 with propulsion means is secured to the frame 1 of the first vessel by hydraulically operated clamps. The drums 2 and tanks 19 can be used for ballast. <IMAGE>

Description

SPECIFICATION Disposal of waste This invention relates to the disposal of waste. Much household and like waste is still disposed of on inland tips and this has obvious disadvantages particuiarly in densely populated areas. These disadvantages are likely to increase as the proportion of putrescibles in the waste increases due to the reclaiming of non-putrescibles such as plastics, glass and paper. It is the object of the present invention to provide improved apparatus for disposing of waste in the sea.

Viewed from one aspect the invention provides a vessel for disposing of waste at sea, comprising at least one rotatable drum which is adapted both to house the waste and to provide buoyancy for the vessel, means for burning the waste in the or each drum, and means for discharging the waste from the or each drum into the sea.

In typical use of such a vessel the waste will be loaded into the drum or drums, the waste will be agitated and burnt in the rotating drum(s) whilst the vessel is travelling to the chosen disposal point, and the resulting waste will then be discharged.

A vessel may be envisaged in accordance with the invention having only one waste drum but it would probably then be necessary to provide separate additional buoyancy means. Preferably therefore the vessel incorporates a plurality of waste drums, typically four in number, which enables all of the vessel's buoyancy to be provided by the drums and full advantage to be taken of the volume available in the vessel for the reception of waste.

The vessel could have its own engine but this is not preferred. In one form of the invention the vessel is simply arranged to be towed, like a barge.

Preferably however the vessel is adapted to be directly linked to a separate prime mover which may then serve at least two such vessels, taking one to sea for disposal of the waste whilst the other or others is or are being filled. In a preferred arrangement, a separate prime mover takes the form of a powered floating vessel which is linkable directly to the waste disposal vessel to pull or push the latter.

Alternatively, the prime mover may be arranged to be carried on the vessel and it may then comprise a wheeled vehicle drivable on and off the vessel. In accordance with an important preferred feature of the invention the rotary waste drums of the vessel are adapted to be driven in rotation by the prime mover and are provided with suitable paddle blades to propel the vessel through the water, so that the rotation of the drums serves both to agitate and aerate the waste and to propel the vessel. If alternatively the waste drums are not driven by the prime mover they may still be provided with paddle blades and thereby rotated by the movement of the vessel through the water.

Preferably a crusher and agitator is provided in the or each drum to increase agitation and aeration of the waste and to break up large pieces. Such a crusher and agitator may conveniently comprise a member freely suspended in the drum and extending axially thereof so as to contact the waste as the drum rotates.

The drums may be driven in rotation in any convenientfashion. In a preferred embodiment the drums are driven by one or more hydraulic motors powered by an engine of the prime mover. Preferably the drums on the port and starboard sides of the vessel are separately driven and are individually controllable to steer the vessel by differential rotation of the port and starboard drums.

The means for burning the waste in the or each drum may again be of any convenient kind. In a preferred form of the invention an oil-fired burner is associated with the or each drum or with a pair of drums and fires into a hollow axle mounted in bearings and carrying the drum. The axle interior is divided into two chambers by a transverse wall, the chambers being provided with respective intake and exhaust openings in the axle wall for the respective entry of burning gases into the drum interior and the return of exhaust fumes to the shaft interior and thence to an exhaust outlet at the end of the shaft remote from the burner. Forced draught means may be provided to control the burning.

An embodiment of the invention will now be described by way of example and with reference to the accompanying diagrammatic drawings, in which Figure 1 is a view in side elevation of a waste disposal vessel accordingly to the invention, with a separate prim mover directly linked thereto; Figure 2 is a plan view of the vessel linked to the prime mover; and Figure 3 is a cross-sectional view of the vessel, on line Ill - Ill of Figure 2.

Referring to the drawings, the vessel comprises a frame 1 carrying four hollow cylindrical drums 2 each mounted on a respective hollow rotary axle 3 (Figure 3) mounted in bearings in the frame. The drums provide all of the buoyancy of the vessel, being arranged to float the vessel at an appropriate level when they are full of waste or water ballasted.

Each drum 2 is provided with two loading and discharging hatches 6 and a driving band 8 (Figure 2). The driving bands of the two drums adjacent the prime mover are directly driven by wheels on the prime mover. The remaining drums are either driven by wheels transmitting rotation from the driving band of one drum to the driving band of an adjacent drum, or by wheels provided with hydraulic motors as described below. A gangway 4 is provided to allow access to the drums.

A prime mover 5 is adapted to be secured to the frame 1 of the vessel by means of hydraulicallyoperated clamps (not shown). The prime mover 5 is provided with three submersible tanks 19 which may be filled and emptied of water to adjust the level of the prime mover in the water. The tanks 19 are preferably compartmented to enable the trim of the prime mover to be adjusted. The tanks 19 may also be used to carry fuel. A trolley 20 is provided which runs on an overhead track 21, a corresponding track 22 being provided on the vessel along which the trolley 20 can run when the vessel is connected to the prime mover 5. The trolley is used to carry out equipment associated with the prime mover which is used in operation of the vessel. Such an arrangement avoids unnecessary duplication of equipment which would otherwise have to be provided on each vessel.The equipment includes: (1) Atwin oil-fire burner, a forced airfan and water spray unit for each pair of drums. In use, these are lowered from the trolley into position 13 through a plated trap.

(2) Wheels which are lowered and clamped between the driving bands 8 of the drums so as to enable the transmission of power to all the drums.

(3) Hydraulic motors which can be lowered and fitted to a clamped-on wheel. Such a motor is of use when operating, for example, a six drum vessel or two four drum vessels connected in series, in which case the transmission of power through the train of drums is no longer practicable.

(4) A hose reel and strainer for pumping out the drums.

(5) Water sprays and thermostats for the exhaust boxes 18.

(6) Lighting units and cable reels.

(7) Means for unlocking the hatches 6 on the drums.

The prime mover has two engines and is provided with all necessary navigation equipment and other facilities for off-shore operation.

Referring now particularly to Figure 3, each drum 2 is provided with a series of paddle blades 9 on its circumference, which also act as stiffeners, so that rotation of the drums propels the vessel through the water. Each hollow axle 3 is divided into inboard and outboard chambers 10 and 11 respectively by a transverse wall 12. An oil-fired burner (not shown) is mountable at 13 together with forced draught means for controlling the burning. The burning gases enter the drum interior via intake louvres 13 and the exhaust exits via exhaust louvres 15 and thence out of the outboard end 16 of the shaft into a stationary box 18 (Figure 1) with an exhaust outlet at the top.

Cooling water sprays are provided in the exhaust box 18, which is self-draining; alternatively the bottom of the exhaust box could comprise a tank for recirculating cooling water. The exhaust boxes 18 preferably do not form a permanent part of the vessel, but are associated with the prime mover 5.

The boxes are then run along the vessel and clamped in place after connection of the prime mover thereto. Acrusherand agitator 17 is freely suspended in the drum, on the axle 3.

Atypical cycle of operation of the illustrated vessel and its prime mover would be as follows.

The empty vessel and its prime mover enter harbour on a rising tide. The vessel is moored end on to a quay alongside a similar loaded vessel. The prime mover is disconnected and ballasted to the level of the loaded vessel, winched into position and connected thereto. The loaded vessel is then taken to sea and when it is an adequate distance from the coast the coolant sprays are started and the burners are fired whilst the vessel is still proceeding towards the disposal point, so as to burn the waste whilst the drums are rotating and the waste is being aerated, agitated and crushed by the rotation of the drums relative to the suspended crushers and agitators.

Having thereby substantially reduced the bulk of the waste, water is sprayed into the drums through the intake louvres 14to damp down any waste components which might otherwise still be light enough to float. The disposal point having been reached, the vessel is stopped, the drum hatches are opened, and the drums are inverted and agitated to discharge the waste. The drums are then again inverted, the hatches are closed, and water is pumped out to the desired ballast level before returning to port.

The extent to which it is necessary to burn the waste before discharge depends mainly on what it contains. The purpose of the burning is to bring the waste to a condition in which it will readily sink when discharged. Thus the burning must be sufficient to have that effect on such components as paper, plastics containers and wool for example, without completely destroying the putrescibles contained in the waste which will be consumed by fish and other sea creatures. A thermostat in the flue controls the air flow and hence the rate of burning. It the waste attains a temperature of about 1 800C this is generally sufficient. Any rubbish which still floats will not leave the drum when it is inverted.

Claims (13)

1. A vessel for disposing of waste at sea, comprising at least one rotatable drum which is adapted both to house the waste and to provide buoyancy for the vessel, means for burning the waste in the or each drum, and means for discharging the waste from the or each drum into the sea.

2. A vessel as claimed in claim 1, comprising a plurality of drums.

3. A vessel as claimed in claim 1 or 2 wherein the or each drum is provided with paddle blades, whereby rotation of the or each drum serves to propel the vessel through the water.

4. A vessel as claimed in any preceding claim, wherein the or each drum is provided with a crusher and/or agitator.

5. A vessel as claimed in claim 4, wherein the crusher and/or agitator comprises a member freely suspended in the drum and extending axially thereof.

6. A vessel as claimed in any preceding claim, wherein the or each drum is rotatable about a hollow axle, a burner firing into the or each hollow axle.

7. A vessel as claimed in claim 6, wherein the or each hollow axle-is divided into two chambers by a transverse wall, each chamber being connected to the interior of the drum, one chamber being intended to supply burning gases to the drum, the other chamber to receive exhaust gases from the drum.

8. The combination of a vessel as claimed in any preceding claim with a prime mover.

9. A combination as claimed in claim 8, wherein the prime mover comprises a powered floating vessel linkable directly to the waste disposal vessel to form a floating unit.

10. A combination as claimed in claim 9, wherein the prime mover is adopted to drive said at least one rotatable drum.

11. A combination as claimed in claim 10, wherein the prime mover drives the or each drum adjacent thereto directly, and further comprising means for transmitting rotation from said adjacent drum(s) to further drum(s).

12. Avessel for the disposal of waste, substantially as herein described with reference to the accompanying drawings.

13. The combination of a prime mover and a vessel for the disposal of waste, substantially as herein described with reference to the accompanying drawings.