The present invention relates to compactors which are used to compact compressible materials, such as domestic, general, or industrial waste.

Current waste compactors, for example as used on off- 5 shore platforms, utilise a single-or multi-cylinder ram arrangement to drive a reciprocable compacting device in the form of a platten or piston. When the ram arrangement is operated, the platten is displaced to cause a working surface area thereof to cooperate _Q with, and compress, waste loaded into the compactor. In order to apply the required compression load, for example approximately 15 tons, to the compacting platten, it is necessary to provide a high pressure oil hydraulic system to operate the ram arrangement. Thus, the com- 5 pactor requires its own hydraulic unit incorporating a high pressure pump, and the compactor platten must be relatively stiff and strong so as to absorb the point load(s) applied by the hydraulic ram(s). Furthermore, the use of high pressure oil as the hydraulic medium creates a fire risk, requiring the imposition of additional safety standards for flame proofing equipment, etc., when the compactor is located in a hazardous environment where flammable gases or liquids are present. It is an object of the present invention to provide a compactor which alleviates or overcomes the fore¬ going disadvantages.

•According to the present invention, there is pro¬ vided a compactor includi-rig a displaceable compacting device, and an inflatable envelope arrangement which, when pressurised, is cooperable with the compacting device

yz >

over an area equivalent to at least a major proportion of the working area of the compacting device, to cause compacting displacement of the latter.

In one embodiment, the compactor includes a frame or housing having an upper part provided with guide means, such as a generally vertical,downwardly opening cylinder, by means of which a compacting platten comprising the compacting device is mounted for generally vertical reciprocating movement in the compactor. The platten is displaced downwardly during its power or compacting stroke to cause an expansive generally horizontal lower surface thereof to engage and compress waste contained in a container or chamber in the lower part of the compactor frame or housing. Within the cylinder, and interposed between a fixed transverse wall at the upper end of the cylinder, and an expansive upper surface of the platten., is the inflatable envelope arrangement, which may comprise a plurality of superimposed, intercommunicating flexible or resilient bags, or a single bag. As viewed in plan, the or each bag is substantially coextensive with the upper surface of the platten which is, in turn, of substantially the same area as the working area or lower surface of the platten. Thus, when the envelope arrangement is inflated, it exerts a substantially uniform downward pressure on the platten over substantially its entire upper surface to downwardly displace the latter. ■ Due to the expansive nature of the envelope arrangement, inflation of the latter to a relatively low pressure, for example

approximately 2 atmospheres (30 p.s.i.), is all that is required to apply the platten to the waste with the required compression load, for example approximately 15 tons, and point loading of theplatten is eliminated. Preferably, the medium used to inflate the envelope arrangement is low pressure air, and the compactor operation may also be pneumatically controlled. Thus, the compactor may be installed in a hazardous environment without the need to adopt additional safety standards with regard to fire proofing. Furthermore, when the compactor is installed on or in an offshore platform, process plant, industrial factory or the like, where compressed air is normally available from an air line, pneumatic power for the compactor may be obtained from such air line, thus eliminating the substantial cost involved in providing the compactor with its own power source.

In order that the invention may be more readily understood, one embodiment of compactor will now be described with reference to the accompanying drawings, in which :-

Figure 1 is a front perspective view of the com¬ pactor with a waste container inserted therein ; Figure 2 is a front view of the compactor shown in Figure 1, on an enlarged scale, with the front wall and the right-hand half of the safety door broken away to reveal internal detail; and

Figure 3 is a vertical section on the line A-A in Figure 2, with the waste container withdrawn. :• Ηeferring to the drawings, the compactor comprises a housing 1 comprising a metal framework 2 skinned with

- T E l OMPI

sheet metal. In the upper part of the housing is mounted an upright, downwardly opening cylinder 3, which is rectangular in plan. The cylinder is carried by, and its upper end is closed by, a transverse wall 4 secured to the framework 2. The cylinder 3 and trans¬ verse wall 4 are of framework construction, the interior of the cylinder frame and the underside of the wall frame being skinned with metal sheet or plate.

Vertically reciprocably mounted within the cylinder 3, in the manner of a piston, is a horizontal, rec¬ tangular compacting platten 5, also of framework construction, and skinned top and bottom with metal sheet or plate. The lower skin is extended upwardly around the periphery of the platten to form a flange 5a_ adjacent, or slidably cooperating with, the cylinder 3. As shown in Figure 3, an upwardly extending pillar in the form of a guide rod or tube 6 is secured to the platten, and is slidable in a bearing comprising a complementary fixed guide tube 7 secured by a boss 7a to the transverse wall 4. A sealing ring 7b is provided between the inner guide- tube 6 and outer fixed guide tube 7 to prevent, or at least substantially restrict, the escape of air upwardly between the tubes.

The platten guide tube 6 is attached to one end of a chain or cable 8, passing over guide pulleys 10 and 11 and secured at its other end to a weight 12 slidable vertically in guides 13 located rearwardly of the cylin¬ der 3. This cable and weight arrangement serves to return, the platten upwardly to its limit position shown in Figure 3 at the end of each downward or power stroke

of the platten.

Within the cylinder, nesting between the transverse wall 4 and the platten 5, is an inflatable envelope arrangement comprising a number of, for example a stack of three, compression bags 14. Each bag 14 has the general configuration of a annulus or "doughnut " which is rectangular in plan, and opens inwardly towards the guide tube 7. As will be apparent from. Figure 3, the bags, in plan, are substantially co- extensive with the platten 5. The bags 14 are formed, for example moulded or fabricated, from a suitable flexible and/or resilient sheet material or laminate, for example natural or synthetic rubber, and/or synthetic plastics material, which may be reinforced. More particularly, each bag may, for example, comprise a pair of rectangular sheets of platics- impregnated nylon mesh forming upper and lower transverse walls 14 a , 14b joined, for example, heat-sealed together, around their outer periphery at 14c_. The walls each have a circular central aperture 14c3 to receive the outer fixed guide tube 7. The diameter of the apertures 14d is larger than the external diameter of the guide tube 7 by an amount to provide sufficient clearance therebetween to eliminate contact, and therefore wear of the bags, during reciprocation of the platten. The upper wall 14a. of the uppermost bag is clamped in an air-tight manner to the lower surface of the transverse wall 4 by a clamp ring 4a bolted to the wall. The lower wall- 14b-of the lowermost bag is similarly clamped in an

air-tight manner to the upper surface of the platten 5 by a clamp ring 5b bolted to the platten. Adjacent intermediate pairs of upper and lower walls 14a_, 14b_ are secured, for example heat-sealed or bonded together,at least around their central apertures 14d. The interiors of the bags intercommunicate via the central apertures 14d, although additional inter¬ connecting passages may be provided through the upper and lower walls. The stack of bags is connected to air supply and vent lines (not shown) . Thus, the bags form an expansible bellows arrangement acting between the transverse wall 4 and platten 5.

As shown in Figure 1, the lower part of the front wall of the compactor housing 1 is provided with an opening la through which a garbage or waste con¬ tainer 15 is insertable into the compactor below the platten 5. The container 15 has a rectangular open- topped waste-receiving, cavity which is slightly larger in plan than the platten 5, and which, in the inserted position of the container, is aligned beneath the cylinder 3. The container 15 is removably mounted on a container feed tray 16 which is retractable into (Figures 1 and 2) and extendable from (Figure 3) the compactor housing. For this purpose, the outer end" of the feed tray 16 is mounted on rollers 16a, and the inner end is mounted on a roller track 16b incorporated in the base of the compactor. Retraction and extension of the feed tray 16 is effected by a pneumatic linear actuator or cylinder 17 (Figure 3 ) in the compactor base. ' .The compactor is intended to receive a container 15

which is overfilled or heaped with waste above the level of its open top, and/or to permit waste to be loaded into the container whilst the latter is operatively located in the compactor. For this purpose, the front 5 wall of the compactor housing 1, and the cylinder 3, are provided with aligned rectangular openings lb, 3b above the opening la_, as shown in Figure 1. To safeguard the compactor operator, a vertically slidable safety door 18 is located between the cylinder 3 and 0 front wall of the housing 1. The door 18 is displaceable by a pneumatic linear actuator or cylinder 19 (Figure 2), from the raised position shown in Figures 2 and 3 during insertion or removal of the container 15, or loading of an inserted container with waste, to a 5 lowered position in which it closes the opening lb, 3b when the platten is executing its downward compacting stroke or its upward return stroke.

The air supply line to the compression bags 14, and also the container feed tray and safety door pneumatic 0 cylinders 17 and 19, are adapted to be coupled, via a .pneumatic control system which may incorporate fluid logic, to a source of relatively low pressure, air, for example air at a pressure of approximately 2 atmospheres. If the compactor is installed on an offshore platform, or 5 in commercial or industrial premises, equipped with a comp¬ ressed air supply, for example a standard 90 p.s.i. (6.33 Kg sq cm) air supply, this is preferably utilised, the compacto being connected to an air line via an appropriate pressure regulator which drops the pressure to the required pressure _Q of approximately 30. .s.i. (2..11 Kg/sq cm).

- 8 -

Alternatively, for example, where no existing or suitable air supply is available, the compactor may be provided with its own air compressor to generate the necessary pneumatic power. As shown in Figure 1, the pneumatic control system is associated with manually operable controls, namely a pair of palm actuated switches 20 controlling platten-operating valves, and container feed tray-insertion and retraction valves 21. In operation the feed tray-retraction valve 21 is depressed, a container 15 loaded with waste is positioned on the retracted container tray 16, and the feed tray-insertion valve 21 is depressed to load the container into the compactor. Additionally or alternatively, the container may be loaded with waste whilst resting on the extended tray, and/or when inserted into the compactor. Once the container is fully inserted, depression of both palm actuated switches 20 will close the safety door 18, and after closure, will interconnect the 30 p.s.i. (0.211 Kg/sq cm) air supply and the air supp line to start inflation of the bags 14 and therefore downward travel of the platten 5. During its downward compression stroke, driven by the progressively inflating bags 14, the platten 5 compresses the heaped waste ^' into the container. At the limit of its downward stroke, when it is disposed adjacent the top of the container, the air supply _{t( the bags i is} automatically cut off, and the air in the bags is vented slowly, allowing the platten to reverse in direction and return to its uppermost limit position shown, under the influence of the platten return weight L2. When the platten is fully retracted, the safety door will reopen, and the compactor

is then ready for further filling. This may be achieved, either by inserting additional waste into the container through the opening lb:, 3b, for example via an approp¬ riate chute (not shown), or by operating the valve 21 to withdraw the tray and container to permit the container to be removed and replaced.

The bags 14 apply a substantially uniform downward load across effectively the entire platten and, when inflated to approximately 30 p.s.i, exert a compact- ing load of approximately 15 tons on the waste in the container via a platten having an effective or working area, in one specific embodiment, of approx¬ imately 16 sq. ft. (4ft x 4ft) (1.49 sq m - 1.22 x 1.22 m) . The compactor is capable of compacting approx- imately Ik tons (1270 Kg) of general waste into a block with overall dimensions of 4ft x 4ft x 3ft, (1.22 x 1.22 x 0.92 m) compaction being effected with approx¬ imately 8 strokes of the platten, the container being topped up with waste between each stroke. The venting of the bags may be effected by a valve which, in its open condition, meters the flow of air to return the platten relatively slowly to its uppermost position. However, it will be understood that the air supply and/or venting may be adjusted as required to adjust the speed of the platten during its downward and/or return stroke.

Appropriate stop means are provided for determining the upper and lower limits of the platten stroke. Such stop means may be pneumatic, and under the control of the pneumatic control system. For example, the position of the platten return weight 12 may be sensed, and utilised to cut off the supply of air to the bags, and vent the

OMPI

the bags, to stop the downward stroke of the platten just above the top of the container 15. Sensing of the platten return weight may also be utilised to close the vent to the bags and stop the upward stroke of the platten in the position shown in Figures 2 and 3, and optionally to re-connect the air supply to the bags if the platten is to automatically cycle or reciprocate several times in succession. In addition, mechanical stop means may be provided to positively stop the platten should it overrun its upper and/or lower pneumatic stops.

Since the pressure is applied to the platten by compressed air contained in the stack of flexible bags 14, unlike a conventional piston and cylinder arrange¬ ment, the platten flange 5a. does not have to sealingly cooperate with, or even contact, the walls of the cylinder 3, and the clearances between the various compo¬ nents may be relatively large. Waste which may enter between the platten flange and cylinder, and which may also pass into the space within the cylinder above the platten, should not normally impair the operation•of the compactor due to the latter clearances, and due to the fact that the only sliding seal, i.e. the seal 7c between the guide tubes 6 and 7 which prevents or limits air leakage from the bags 14 upwardly between the tubes-, is enclosed within the bags 14 and therefore isolated from such waste.

^' Since the upper wall 14,a of the uppermost bag and the lower wall 14b of the lowermost bag are fixed

relative to the transverse wall 4 and platten 5 respectively, minimal relative rubbing movement can occur which could cause chafing or other wear of the former walls. Furthermore, the provision of clearance between the wall of the cylinder 3 and the periphery of the stack of bags 14, together with the provision of the webs formed by the inter¬ mediate upper and lower walls 14a_, 14b which not only strengthen the stack, but also prevent or restrict outward bowing or expansion of the stack when inflated, prevent the periphery of the stack from rubbing and chafing against the cylinder wall above the platten flange 5a.

The container 15 may, if required, be lined with a plastics liner (not shown) before filling with waste, in which the waste is enclosed and transported after compaction and removal from the container.

It will be understood that various modifications may be made without departing from the scope of the present invention.

For example, the number and/or configuration of the compression bags may be varied. Instead of a single bag or stack, two or more side-by-side bags or stacks could be arranged to act on the platten. The bags may be discrete, or integrated to form a bellows- type structure. The bags may be reduced in cross- section, or may be circular instead of rectangular in ^• plan, and the central sliding pillar arrangement 6, 7 may be replaced' by two or more pillar arrangements disposed externally of the bags, for example at the corners of the rectangular, platten 5 and transverse wall 4, thus eliminating the necessity of perforating

O PI

the bag walls with central apertures 14d or equiva¬ lent. The platten may likewise be circular in plan instead of rectangular.

The underside of the platten may be formed with a - ^> downwardly projecting raised zone or anvil, so as to intensify the pressure applied to the central region of the waste in the container, enhancing compaction and facilitating packaging.

The venting bf the bag(s) or other envelope ⁰ arrangement may be controlled by a valve, or may be continuous at a rate which is restricted so as to be significantly less than the inflation rate occurring during the compression stroke of the platten.

Although, in the specific embodiment,the compactor is powered and controlled exclusively by compressed air, other low-pressure gases or liquids may be employed, for example water at supply or mains pressure. Furthermore, although the pressurised medium is preferably derived from an existing supply, the compactor could ⁰ alternatively be provided or associated with its own pressure source, for example pump or compressor. Whilst the compactor herein described is of particular utility on offshore platforms due to its inherent capability of operating safely in hazardous ^ environments, it has numerous other applications.

For example, it may be used to compact domestic waste, industrial or commercial waste such as swarf, paper or card, cartons or other packaging materials, ^* or to compact compressible materials other than waste, for 0 example to facilitate transport and/or storage of such

_* -**.. materials, and in the latter event, the compactor may be incorporated in a production line. Alternatively,

the compactor could be used to compact fruit, such as grapes or apples, to extract juice therefrom. Although the illustrated compactor has a vertically reciprocable platten, the platten could alternatively be reciprocable along a horizontal or inclined path. The platten may be displaceable into the container during its downward stroke, instead of stopping at or above the level of the top of the container. The compactor may incorporate an in-built waste chamber, instead of utilising a separate container, the chamber incorporating appropriate waste inlet and discharge ports, etc.

The various dimensions stated are purely exemplary, and the components may be of other dimensions and configurations. Likewise, the inflation pressure of the envelope arrangement may be greater or less than 25 to 30 p.s.i. (1.76 to 2.11 Kg/sq.. cm), the compression • load may be other than 15 to 20 tons (1524 to 2032 Kg), and the effective or working area of the platten may be other than 12 to 16 sq.ft. (1.12 to 1.49 sq. m) .

Instead of stopping and/or reversing the platten at the end of its upward or downward stroke in dependance upon the position of the platten return weight 12, the position or movement of other components, for example the chain or cable 8 or platten 5 could alternatively be sensed. Additionally or alternatively, the upward and/or downward stroke could be terminated ^' or reversed under the control of appropriate means operable to detect the pressure or changes in pressure in the bags or associated lines.

-fV X

O PI

WIPO _Λ*-

^ flN O^