macerator

Abstract

A macerator comprising: a maceration chamber comprising a flat base, wherein the base has a geometric centre; an impeller adjacent the base and configured to rotate about an impeller axis; and a drain inlet at the edge of the impeller, wherein the impeller axis is offset from the geometric centre of the base.

Description

[0001] P605579PC00

[0002] MACERATOR

[0003] Technical Field

[0004] The invention relates to a macerator.

[0005] Background of the Invention

[0006] Macerators process solid waste products by reducing the solid product to a slurry in water, which can then be more readily disposed of through conventional drainage systems. It is beneficial to reduce the solid waste as quickly and as efficiently as possible, and to reduce the likelihood of solid waste loaded into the macerator becoming trapped or otherwise not being macerated.

[0007] It is an objective of the current invention to address some of the limitations associated with the current state of the art.

[0008] Summary of the Invention

[0009] A first aspect of the invention provides a macerator comprising: a maceration chamber comprising a flat base, wherein the base has a geometric centre; an impeller adjacent the base and configured to rotate about an impeller axis; and a drain inlet adjacent the impeller, wherein the impeller axis is offset from the geometric centre of the base.

[0010] Providing an impeller arranged to rotate about an impeller axis offset from the geometric centre of the base may create an asymmetry within the maceration chamber. This asymmetry may assist in the maceration of waste by creating an asymmetric orbit of liquid slurry within the maceration chamber and / or may reduce the likelihood of waste becoming trapped and not being macerated.

[0011] The macerator may further comprise a sidewall upstanding from the base to define a conical volume comprising an axis of rotational symmetry. The impeller axis may be offset from the axis of rotational symmetry. The offset may be an angular offset and / or a translational offset between the impeller axis and the axis of rotational symmetry.

[0012] Providing a maceration chamber defined by a sidewall having an axis of rotational symmetry may help to control and / or direct the movement of liquid slurry in the maceration chamber as the impeller rotates. Arranging the impeller to rotate about an impeller axis offset from the axis of rotational symmetry may create an asymmetry within the maceration chamber. This asymmetry may assist in the maceration of waste by P605579PC00 creating an asymmetric orbit of liquid slurry within the maceration chamber and / or may reduce the likelihood of waste becoming trapped and not being macerated.

[0013] An edge of the impeller may be adjacent the intersection between the base and a portion of the sidewall.

[0014] Providing an edge of the impeller adjacent a portion of the sidewall may reduce the likelihood of waste becoming trapped against the sidewall and not being macerated. The sidewall may also be used to help macerate the waste, for example as waste impacts upon the sidewall having been moved by the rotating impeller.

[0015] A second aspect of the invention provides a macerator comprising: a maceration chamber comprising a base; and a sidewall upstanding from the base, the sidewall defining a conical volume comprising an axis of rotational symmetry; an impeller adjacent the base and configured to rotate about an impeller axis, wherein the impeller axis is offset from the axis of rotational symmetry; and a drain inlet adjacent the impeller.

[0016] Providing a maceration chamber defined by a sidewall having an axis of rotational symmetry may help to control and / or direct the movement of liquid slurry in the maceration chamber as the impeller rotates. Arranging the impeller to rotate about an impeller axis offset from the axis of rotational symmetry may create an asymmetry within the maceration chamber. This asymmetry may assist in the maceration of waste by creating an asymmetric orbit of liquid slurry within the maceration chamber and / or may reduce the likelihood of waste becoming trapped and not being macerated.

[0017] The offset may be an angular offset and / or a translational offset between the impeller axis and the axis of rotational symmetry.

[0018] Providing a translational offset between the impeller axis and the axis of rotational symmetry may allow the maceration chamber and impeller to be asymmetrical whilst still have the impeller rotate about an axis aligned with the sidewall and / or the base. Providing an angular offset between the impeller axis and the axis of rotational symmetry may allow the impeller to be inclined relative to the sidewalls. This may allow the orbit of liquid slurry in the maceration chamber to be controlled, for example to direct waste towards a sidewall or the drain inlet.

[0019] The base may be flat and have a geometric centre. The impeller axis may be offset from the geometric centre of the base. P605579PC00

[0020] Providing an impeller arranged to rotate about an impeller axis offset from the geometric centre of the base may create an asymmetry within the maceration chamber. This asymmetry may assist in the maceration of waste by creating an asymmetric orbit of liquid slurry within the maceration chamber and / or may reduce the likelihood of waste becoming trapped and not being macerated.

[0021] An edge of the impeller may be adjacent the intersection between the base and a portion of the sidewall.

[0022] Providing an edge of the impeller adjacent a portion of the sidewall may reduce the likelihood of waste becoming trapped against the sidewall and not being macerated. The sidewall may also be used to help macerate the waste, for example as waste impact upon the sidewall having been moved by the rotating impeller.

[0023] A third aspect of the invention provides a macerator comprising: a maceration chamber comprising a base; and a sidewall upstanding from the base; an impeller adjacent the base and configured to rotate about an impeller axis, wherein an edge of the impeller is adjacent the intersection between the base and a portion of the sidewall.

[0024] Providing an edge of the impeller adjacent a portion of the sidewall may reduce the likelihood of waste becoming trapped against the sidewall and not being macerated. The sidewall may also be used to help macerate the waste, for example as waste impact upon the sidewall having been moved by the rotating impeller.

[0025] The portion of the sidewall adjacent the edge of the impeller may be substantially perpendicular to the base.

[0026] Providing a sidewall adjacent the impeller and arranged perpendicular to the base may help to direct the flow of liquid slurry within the maceration chamber whilst the impeller is rotating. This may be used for example to reduce the likelihood of waste not being macerated, or to direct waste back towards the impeller and / or the drain inlet.

[0027] The portion of the sidewall adjacent the edge of the impeller may extend at an acute angle relative to the base, preferably wherein the angle is between 80 and 90 degrees. P605579PC00

[0028] Providing a sidewall adjacent the impeller and extending at an acute angle relative to the base may help to direct liquid slurry driven by the impeller back into the centre of the maceration chamber for mixing and / or maceration.

[0029] The macerator of the third aspect of the invention may further comprise a drain inlet adjacent the impeller.

[0030] Providing a drain inlet adjacent or at an edge of the impeller may provide a convenient method of collecting waste macerated by the impeller and / or any adjacent components. In particular the drain inlet may be located underneath the edge of the impeller such that macerated waste is fed into the drain inlet at least partially due to gravity.

[0031] The base may be flat and have a geometric centre. The impeller axis may offset from the geometric centre of the base.

[0032] Providing an impeller arranged to rotate about an impeller axis offset from the geometric centre of the base may create an asymmetry within the maceration chamber. This asymmetry may assist in the maceration of waste by creating an asymmetric orbit of liquid slurry within the maceration chamber and / or may reduce the likelihood of waste becoming trapped and not being macerated.

[0033] The sidewall may define a conical volume comprising an axis of rotational symmetry. The impeller axis may be offset from the axis of rotational symmetry. The offset may be an angular offset and / or a translational offset between the impeller axis and the axis of rotational symmetry.

[0034] Providing a maceration chamber defined by a sidewall having an axis of rotational symmetry may help to control and / or direct the movement of liquid slurry in the maceration chamber as the impeller rotates. Arranging the impeller to rotate about an impeller axis offset from the axis of rotational symmetry may create an asymmetry within the maceration chamber. This asymmetry may assist in the maceration of waste by creating an asymmetric orbit of liquid slurry within the maceration chamber and / or may reduce the likelihood of waste becoming trapped and not being macerated.

[0035] The sidewall adjacent the impeller may be curved to substantially match a portion of the circumference of the impeller. P605579PC00

[0036] Providing a sidewall curved to match the circumference of the impeller may help to direct the orbit of liquid slurry in the maceration chamber driven by the impeller rotating. For example, the curvature of the sidewall may help to direct liquid slurry energized by the rotating impeller towards the centre of the maceration chamber for mixing and / or maceration.

[0037] The sidewall may define a sidewall recess adjacent the base. A portion of the periphery of the impeller may be arranged to rotate within the sidewall recess.

[0038] Providing a sidewall recess may allow a portion of the impeller to be embedded in or housed within the sidewall as it rotates. This may for example allow the area over which waste is macerated by the impeller and / or adjacent components to be limited and / or controlled. This may also assist in directing waste to be macerated towards the cutter ring and / or macerated waste out of the hopper.

[0039] The maceration chamber may be inclined relative the vertical.

[0040] Inclining the maceration chamber may help to control the flow and / or orbit of liquid slurry within the maceration chamber. This may for example assist in draining liquid slurry from the macerator, particularly when the impeller is not rotating.

[0041] The base may be elliptical.

[0042] An elliptical base, optionally with sidewalls upstanding therefrom, may provide a convenient shape for controlling the orbit or flow of liquid slurry within the maceration chamber. An ellipsis may provide a convenient shape for accommodating a translational offset of the impeller relative to the geometric centre of the base and / or the axis of rotational symmetry as described previously.

[0043] The base may comprise a base recess. The impeller may be arranged to rotate within the base recess.

[0044] Arranging the impeller within a base recess may help to macerate waste within the maceration chamber. This may also allow greater control over the area over which maceration occurs and / or may assist in controlling the outflow of liquid slurry from the maceration chamber. P605579PC00

[0045] The base recess may comprise cutting apertures about the periphery of the base recess, the cutting apertures suitable for cutting solid particulates. Macerated waste may be able to flow from the maceration chamber to a drain through the cutting apertures.

[0046] Solid waste may be macerated or broken apart through shear action as it is caught between the cutting apertures and the rotating impeller. By using the cutting apertures as an outlet from the maceration chamber, they may also be used to control the extent to which waste must be macerated before it exits the maceration chamber (i.e. the width of the cutting aperture may set the maximum diameter of solid waste which may exit the maceration chamber).

[0047] The impeller may comprise at least one projection extending into the maceration chamber. The at least one projection may be arranged to rotate with the impeller about the impeller axis. Each projection may be referred to as a rotating projection, a finger, a blade or a stud.

[0048] Providing at least one projection arranged to rotate with the impeller may reduce the likelihood of solid waste becoming trapped in an area of the maceration chamber where maceration does not occur. The projections may be used to increase the area over which solid waste interacts with the impeller and hence may reduce the likelihood of solid waste not being macerated.

[0049] The base may be inclined relative to the horizontal.

[0050] Inclining the base relative to the horizontal provides a lowermost portion of the base where liquid slurry in the maceration chamber will fall to under the effect of gravity. This may improve ease of draining liquid, optionally macerated waste, out of the maceration chamber, for example via a drain inlet.

[0051] A portion of the periphery of the impeller may be located at a lowermost region of the base.

[0052] Providing a portion of the impeller at a lowermost region of the base may reduce the likelihood of waste in the maceration chamber not being macerated, since waste to be macerated will naturally fall towards this region under the effect of gravity.

[0053] The macerator may further comprise a drain inlet. The drain inlet may be located below a lowermost region of the base. P605579PC00

[0054] Providing a drain inlet below a lowermost region of the base may improve ease of draining liquid and / or macerated waste from the maceration chamber, since macerated waste may fall towards the lowermost region and hence the drain inlet due to gravity.

[0055] The maceration chamber may further comprise an opening at a top of the maceration chamber; and an openable lid for covering the opening in the top of the maceration chamber. The lid may be openable to provide user access to insert maceratable materials into the maceration chamber. The openable lid may have a pivotal connection to a body of the macerator.

[0056] Alternatively, the maceration chamber further comprise an inlet at a top of the maceration chamber, and wherein the maceration chamber is couplable in-line within a drainage system.

[0057] The macerator may be configured to process healthcare waste including incontinence briefs, pads, pans, wipes, dog waste or food waste.

[0058] Brief Description of the Drawings

[0059] One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0060] Figure 1 shows a macerator;

[0061] Figure 2 shows a side view of the macerator of Figure 1;

[0062] Figure 3 shows a schematic representation of a cross section of the macerator of Figure 2;

[0063] Figure 4 shows a schematic representation of a food disposer; and

[0064] Figures 5 to 16 each show a schematic representation of an example of a maceration chamber.

[0065] Detailed Description

[0066] Figure 1 shows a macerator 1 for macerating solids with water to produce macerated waste (which may be referred to as a slurry) which may more easily be distributed through drainage systems such as waste pipes, for example in a hospital. The water may be P605579PC00 introduced to the macerator 1 using nozzles (not shown). More generally, the macerator 1 may comprise a cleaning fluid inlet into the maceration chamber (such as nozzles injecting water) for cleaning all interior surfaces of the macerator 1. This process of maceration may also be referred to as processing waste. The macerator 1 may be configured to process healthcare waste such as bedpans, incontinence briefs, pads, wipes or dog waste.

[0067] The macerator 1 may be a free-standing macerator comprising a lid 2 movable between a closed position (as shown in Figure 1) and an open position (as indicated in Figure 2). The lid 2 may be coupled to a body 4 of the macerator 1 via a pivotal connection 6. The pivotal connection 6 may comprise a simple hinge joint, and movement of the lid 2 may be manual or electrically actuated.

[0068] The macerator 1 comprises a maceration chamber 10 in which solid waste is macerated as shown in Figure 3. There is provided an opening 11 at the top of the maceration chamber 10. In the closed position, the lid 2 covers the opening 11 to prevent access to the maceration chamber 10. The lid 2 may comprise a seal, optionally a compressible seal, configured to form a watertight seal with the macerator body 4 when the lid is in the closed position. When the lid 2 is in the open position as shown in Figure 3, a user of the macerator (who may be referred to hereinafter as a user) is provided access to insert or load waste to be macerated into the macerator chamber 10 via the opening 11. The opening 11 may be substantially circular, which may provide a convenient shape for allowing waste of varying shapes and / or sizes to be loaded into the maceration chamber 10. Alternatively, the opening 11 may be oval, rectangular or any other shape. The shape and / or size of the opening 11 may be selected based upon the waste to be macerated.

[0069] Adjacent the base 12 of the maceration chamber 10 there is provided an impeller 20 arranged to rotate about an impeller axis Al. The impeller 20 may be circular, elliptical, or may take any other shape. The impeller 20 is configured to break apart solid waste and may therefore comprise one or more projections 22 extending from the impeller 20 into the maceration chamber 10 to move and break apart large pieces of solid waste as the impeller 10 rotates. Each projection 22 may also be referred to as a rotating projection, a blade, a finger or a stud. It will be appreciated that the water is introduced into the maceration chamber 10 to form a slurry as the large pieces of solid waste are broken apart.

[0070] The macerator 1 may comprise a drain inlet 30 adjacent the impeller 20. The drain inlet 30 may be (solely) gravity fed, i.e. in the absence of a pumped drainage system coupled P605579PC00 to the drain inlet. The drain inlet may be always open. At the end of each macerator cycle the maceration chamber 10 may fully drain through the drain inlet 30. It will be appreciated that the drain inlet 30 shown in Figure 3 is a simplified representation. The drain inlet 30 may be connected to a further drainage conduit, such as for example a macerator waste outlet or an external drainage system (not shown). The external drainage system may for example be the drainage system of a building.

[0071] Alternatively, the macerator 1 may be a food disposer 100, such as for example an undersink macerator as shown schematically in Figure 4. The food disposer 100 comprises an inlet 110 that is always open and through which waste to be macerated (i.e. food waste) and water may be received. The food disposer 100 may be connected in-line with an external drainage system 200 (shown in broken line) such as for example a sink drain. The external drainage system my include an upper part 201 couplable to the sink drain with a flexible (e.g. rubber) protective shield 202, and a lower part 203 couplable to a waste pipe (not shown). The food disposer 100 further comprises an impeller 20 for macerating waste. The area immediately surrounding the impeller 20 may be referred to hereinafter as the maceration zone, defined as the volume in which the majority of maceration occurs. It is preferable to space the maceration zone from the inlet 110 to reduce the likelihood of macerated waste being forced out of the food disposer via the inlet 110 and to distance the impeller from a user's fingers. A conduit may be provided to connect the inlet 110 to the maceration zone. More generally, the conduit may be said to define a maceration chamber 10 as described previously with respect to Figure 3. The food dispenser 100 inlet and outlet may both be open at all times. Unlike the macerator 1, the food dispenser 100 has no sealed lid over the maceration volume, only the optional protective shield 202.

[0072] The impeller 20 is configured to rotate about an impeller axis Al and may comprise any combination of lugs, blades, cutting surfaces and grinding surfaces (shown schematically as a cutting surface 24 at the periphery of the impeller 20) to macerate waste as the impeller 20 rotates. There is further provided a drain inlet 30 through which macerated waste may drain from the food disposer 100.

[0073] It will be appreciated that in the following description, any reference made to the macerator 1 may be applied to the food disposer 100.

[0074] It may be beneficial to offset or otherwise position the impeller 20 within the maceration chamber 10. This offset may help to control or influence the orbit of the liquid or slurry within the maceration chamber 10, the orbit here defined as the bulk flow direction of P605579PC00 liquid slurry within the maceration chamber, driven for example by rotation of the impeller 20. This control may for example assist with macerating waste by creating turbulence and / or mixing in the liquid and / or may reduce the likelihood of solid waste becoming trapped or lodged in regions of the maceration chamber 10 where maceration does not occur.

[0075] Examples of impeller offsets and positions will now be described with reference to Figures 5 to 15, each of which show a simplified representation of a maceration chamber 10. It will be appreciated that each simplified representation may be in accordance with the maceration chamber 10 described with reference to Figure 3 or 4. It will further be appreciated that although not shown, the impeller 20 of each example of a maceration chamber 10 may be provided with one or more projections 22 as described previously.

[0076] The base 12 may be flat and have a geometric centre 13 as shown for example in Figures 5 to 10. The geometric centre 13 is here defined as the centroid of the shape defined by the base 12 and may alternatively be referred to as the centre 13 or the middle point 13 of the base 12. The impeller axis Al may be offset from the geometric centre 13 of the base 12. That is to say that the impeller axis Al is offset translationally from the centroid 13 of the base 12, such that the impeller axis Al does not pass through the centre 13 of the base 12. By offsetting the impeller axis Al from the centre 13 of the base 12, an asymmetry is created within the maceration chamber 10 since the impeller is closer to one portion of the edge of the base 12 than another. This asymmetry may help to control or disrupt the orbit of slurry within the maceration chamber 10 as described previously.

[0077] Figure 5 shows an example of a maceration chamber 10 comprising a sidewall 14 upstanding from the base 12. It will be appreciated that the sidewall 14 may comprise a single sidewall extending around the periphery of the base or may be formed of multiple distinct panels coupled together. The following description referring to a single sidewall 14 may also be applied to a sidewall comprising multiple panels coupled together. The sidewall of Figure 4 extends substantially perpendicular to the base. Figure 6 shows an alternative example of a maceration chamber 10 comprising a sidewall 14 which forms an obtuse angle with the base 12. Providing a sidewall 14 which tapers towards the base 12 may for example help to direct waste loaded into the maceration chamber 10 towards the impeller 20 for maceration.

[0078] Figure 7 shows a further example of a maceration chamber 10 comprising a sidewall 14 upstanding from the base 12. The sidewall 14 defines a sidewall recess 18 adjacent the base 12 in which a portion of the periphery of the impeller 20 is arranged to rotate. As P605579PC00 such, the sidewall recess 18 may be curved or otherwise shaped to match the profile of the periphery of the impeller 20 to receive the impeller 20. The impeller 20 may be said to be partially embedded or housed by or within the sidewall 14. Providing a sidewall recess 18 for the impeller 20 to partly rotate in may help to control the area over which maceration occurs.

[0079] It may be preferable to incline the base 12 relative to the horizontal such that there is a lowermost region of the base 12 measured relative to the vertical. Examples of this arrangement are shown in Figures 8 to 10. Solid waste and liquid slurry will fall towards the lowermost region of the base 12 under the effect of gravity. As such it is preferable to offset the impeller 20 such that a portion of the periphery of the impeller 20 is located at the lowermost region of the base 12 as shown in Figures 8 to 10. It is further preferable to provide a drain inlet 30 below the lowermost region of the base 12, such that macerated waste will natural fall towards the drain inlet 30 under the effect of gravity. This arrangement may allow drainage of the macerator 1 to be (solely) gravity fed, i.e. in the absence of a pumped drainage system coupled to the drain inlet 30. The drain inlet 30 may be always open. At the end of each macerator cycle the maceration chamber 10 may fully drain through the drain inlet 30.

[0080] Figure 8 shows an example of a maceration chamber 10 comprising a sidewall 14 that extends substantially perpendicular to the base 12. It may be preferable to provide a portion of the sidewall 14 extending perpendicular to the base 12 where the impeller 20 is offset from the geometric centre 13 of the base 12 such that the periphery of the impeller 20 is adjacent the sidewall 14. This may help to direct the orbit of liquid driven by the rotating impeller 20. Alternatively, the sidewall 14 may extend from the base 12 at an acute angle, optionally at and angle of between 80 and 90 degrees.

[0081] Figure 9 shows a further example of a maceration chamber 10 comprising a sidewall 14 having a different profile. The maceration chamber 10 of Figure 9 comprises a ramped portion 15 inclined relative to the base 12. Providing a ramped portion 15 may help to direct waste to be macerated towards the impeller 20 and / or may reduce the likelihood of waste becoming trapped in regions of the maceration chamber 10 where maceration does not occur. The ramped portion 15 may be considered a portion of the base 12 (such that the base 12 is non-planar) or a portion of the sidewall 14 (such that the base 12 is planar). The ramped portion 15 may extend from the base 12 at a ramp angle 0 of between 0 and 25 degrees. P605579PC00

[0082] Figure 10 shows a further example of a maceration chamber 10 comprising a ramped portion 15 extending from the base 12. In the illustrated example, the ramped portion 15 is curved so as to define a concave inner surface of the maceration chamber 10. It will be appreciated that the term curved here describes the profile of the ramped portion 15 in the plane shown in Figure 7b. It will further be appreciated that the ramped portion 15 may be curved in a second direction around the perimeter of the base 12. As such the ramped portion 15 may be said to be curved in two directions. The ramped portion 15 may extend from a region of the base 12 adjacent the periphery of the impeller 20 as shown in Figure 7b. Where the ramped portion 15 is curved, the section of the ramped portion immediately adjacent the base 12 may form a tangential ramp angle 0 of between 0 and 25 degrees relative to the base 12. Providing a curved ramp portion 15 may provide a convenient surface for directing waste to be macerated towards the impeller 20. It may also provide a larger internal volume within the maceration chamber 10 compared to a flat ramped portion 15 as shown in Figure 7. This increased internal volume may help to control and / or allow the orbit of liquid slurry within the macerator 1.

[0083] It will be appreciated that although only shown as applied to an inclined base 12, a maceration chamber 10 comprising a flat base 12 (for example as shown in Figures 5 to 7) may also be provided with a ramped portion 15.

[0084] Figure 11 shows a further example of a maceration chamber 10 comprising a sidewall 14. The sidewall 14 comprises a first portion 14a and a second portion 14b on opposite sides of the base 12. It will be appreciated that the simplified representation shown in Figure 11 indicates the profile of the sidewall 14 in a single plane taken across the base 12 only. The sidewall 14 may extend around the periphery of the base 12 as described previously and as such may for example smoothly transition between the profile of the first portion 14a and the second profile 14b. The first portion 14a of the sidewall 14 extends from the base 12 at a first angle al and the second portion 14b of the sidewall 14 extends from the base 12 at a second angle a2. The first angle al may be different to the second angle a2. Although shown as the first angle al being acute and the second angle a2 being obtuse, it will be appreciated that each angle al, a2 may take any value. Where the first and second angles al, a2 take the same oblique value (such as for example shown in Figure 5) the sidewall 14 defines a truncated cone. Where the first and second angles al, a2 each take a different value (such as for example shown in Figures 8 to 10) the sidewall 14 defines a truncated oblique cone (i.e. a truncated cone which would otherwise have an apex not directly above the centre of its base). More generally the sidewall 14 may define a conical volume. P605579PC00

[0085] The sidewall 14 defines a central axis A2 of the maceration chamber 10. Where the sidewall defines a truncated cone, the central axis A2 may be an axis of rotational symmetry. Where the sidewall defines a truncated oblique cone, the central axis A2 may be the axis of the oblique cone. The central axis A2 may more generally be defined as the axis passing through the centre of the maceration chamber 10, as defined by the sidewall 14. Where each portion 14a, 14b of the sidewall 14 extends from the base at a different angle (such as for example shown in Figures 8), the central axis A2 is inclined relative to the base 12 and / or the vertical. As such the maceration chamber 10 may be said to be inclined relative to the vertical.

[0086] The impeller axis Al may be offset from the central axis A2. Figure 11 illustrates a first example where the offset is an angular offset, such that the central axis A2 is inclined relative to the impeller axis Al. It will be appreciated that the angle formed between the impeller axis Al and the central axis A2 may take any value. Figure 12 illustrates another example where the offset is a translational offset only, such that the impeller axis Al and the central axis A2 are parallel. Where the central axis A2 is inclined relative to the base, a base recess 16 in which the impeller 20 is arranged to rotate may be provided to accommodate the inclined impeller axis Al. Figure 12 shows the impeller 20 offset such that the periphery of the impeller 20 is adjacent to and spaced apart from the sidewall 14. It will be appreciated that the impeller 20 may be offset such that the periphery of the impeller is directly adjacent to the sidewall 14.

[0087] Figure 13 illustrates a further example of a maceration chamber 10 where the offset between the impeller axis Al and the central axis A2 comprises both an angular and a translational offset. It will be appreciated that where the base 12 is flat and has a geometric centre 13 as defined previously, the central axis A2 will pass through the geometric centre 13 as shown in Figure 13. As such, the translational offset between the central axis A2 and the impeller axis Al is comparable to the offset described with reference to Figures 5 to 7. The translational offset between the central axis A2 and the impeller axis Al may be taken at the level of the base 12 such that the translational offset is defined as the two axes not intersecting at the base 12. Alternatively, the translational offset may be defined as the two axes Al, A2 not intersecting at any point along their length. It will be appreciated that a rotational offset between the axes Al, A2 may still apply even where the axes do not intersect, for example by considering the angle between the direction of each axis. P605579PC00

[0088] Figure 14 shows a further example of a maceration chamber 10 comprising a sidewall 14 that defines a central axis A2 from which the impeller axis Al is offset, similar to that described with reference to Figure 13. Details of this translational and rotational offset will therefore not be repeated here. The maceration chamber 10 of Figure 14 further comprises a base 12 inclined relative to the horizontal, with the impeller 20 arranged to rotate within a recess 16 in the base. As described with reference to Figures 8 to 10, it is preferable to provide a portion of the periphery of the impeller 20 at the lowermost region of the base 12 since waste will fall to this point due to gravity. The base recess 16 may comprise at least one cutting aperture 17 arranged about the periphery of the base recess 16. These may be used to cut solid waste particles, for example as waste is trapped between the periphery of the base recess 16 and the rotating impeller 20. The impeller 20 may be provided with corresponding cutting portions (not shown) to improve the likelihood of waste between the cutting aperture(s) 17 and the impeller 20 being macerated. The cutting aperture(s) 17 may also be used to allow liquid slurry to flow from the maceration chamber 10 to a drain outlet 30. In this way, the size of the cutting aperture(s) 17 may be chosen so as to limit the maximum size of solid waste particles that may drain from the maceration chamber 10.

[0089] Figure 15 illustrates a further example of a maceration chamber 10 comprising an impeller 20 offset from the central axis A2 of the maceration chamber 10 by a translational offset. It will be appreciated that the central axis A2 is here defined by the sidewall 14 and is not defined by the ramped portion 15. The maceration chamber 10 comprises an impeller 20 that forms the base 12 of the maceration chamber 10. That is to say that the impeller 20 is sized to fully cover the base of the maceration chamber 10. The ramped portion 15 may extend from immediately adjacent the periphery of the impeller 20 and may help to direct waste to be macerated towards the impeller 20 as described previously.

[0090] More generally, the impeller 20 may be sized and / or positioned relative to the base 12 such that at least a portion of the edge of the impeller 20 is immediately adjacent the sidewall 14. Where the maceration chamber 10 comprises a base 12 and a sidewall 14 upstanding from the base as described previously, an intersection is defined at the interface between the base 12 and the sidewall 14. The intersection may alternatively be referred to as the edge or perimeter of the base 12. As such, the impeller 20 may be arranged such that an edge of the impeller 20 is adjacent, optionally immediately adjacent, at least a portion of the intersection between the base 12 and the sidewall 14. Immediately adjacent may here be defined as a gap of less than 5 millimetres, preferably less than 2 millimetres, further preferably less than 1 millimetre existing between the edge of the impeller 20 and the sidewall 14 to which the impeller 20 is adjacent. Providing an edge of P605579PC00 the impeller immediately adjacent the sidewall 14 may improve the performance of the macerator 1, for example by generating a beneficial orbit of liquid slurry about the sidewall 14 adjacent the impeller 20. It may be preferable to provide a sidewall 14 adjacent the impeller 20 having a curved profile to substantially match that of the circumference of the impeller 20. This may for example help to control the orbit of liquid slurry driven by the impeller 20.

[0091] It will be appreciated that various aspects of the examples of maceration chambers 10 described with reference to Figures 5 to 15 may be combined. Figure 16 shows an example of a maceration chamber 10 comprising an inclined planar base 12 having a geometric centre 13 as described previously. The maceration chamber 14 further comprises first and second sidewall portions 14a, 14b upstanding from the base to define a central axis A2, the central axis A2 passing through the geometric centre 13 of the base 12. The impeller 20 is offset translationally from both the geometric centre 13 and the central axis A2 such that the edge of the impeller 20 is immediately adjacent the intersection between the base 12 and the second portion 14b of the sidewall 14. The edge of the impeller 20 adjacent the sidewall 14 is provided at the lowermost region of the base 12, and a drain inlet 30 is provided beneath the lowermost region of the base 12 and the edge of the impeller 20 at this lowermost region. The second portion 14b of the sidewall 14 is substantially perpendicular to the base 12 and the impeller 20. Each of the first 14a and second 14b portions of the sidewall 14 extend from the base 12 at a different angle such that they define a truncated oblique cone as defined previously. The impeller 20 is arranged to rotate about an impeller axis Al substantially perpendicular to the base 12, and as such the impeller axis Al is offset rotationally from the central axis A2 of the maceration chamber 10. The maceration chamber 10 further comprises a ramped portion 15 as described previously with reference to Figure 9, although it will be appreciated that the ramped portion 15 may be curved as described with reference to Figure 10.

[0092] Various modifications, whether by way of addition, deletion and / or substitution, may be made to all of the above described embodiments to provide further embodiments, any and / or all of which are intended to be encompassed by the appended claims.

Claims

P605579PC00Claims1. A macerator comprising: a maceration chamber comprising a base; and a sidewall upstanding from the base, the sidewall defining a conical volume comprising an axis of rotational symmetry; an impeller adjacent the base and configured to rotate about an impeller axis, wherein the impeller axis is offset from the axis of rotational symmetry; and a drain inlet adjacent the impeller.

2. A macerator according to claim 1, wherein the offset is an angular offset and / or a translational offset between the impeller axis and the axis of rotational symmetry.

3. A macerator according to claim 1 or 2, wherein the base is flat and has a geometric centre, and wherein the impeller axis is offset from the geometric centre of the base.

4. A macerator according to any of claims 1 to 3, wherein an edge of the impeller is adjacent the intersection between the base and a portion of the sidewall.

5. A macerator comprising: a maceration chamber comprising a base; and a sidewall upstanding from the base; an impeller adjacent the base and configured to rotate about an impeller axis, wherein an edge of the impeller is adjacent the intersection between the base and a portion of the sidewall.

6. A macerator according to claim 5, further comprising a drain inlet adjacent the impeller.

7. A macerator according to any of claims 5 to 6, wherein the base is flat and has a geometric centre, and wherein the impeller axis is offset from the geometric centre of the base.

8. A macerator according to any of claims 5 to 7, wherein the sidewall defines a conical volume comprising an axis of rotational symmetry, wherein the impeller axis is offset from the axis of rotational symmetry, optionally wherein the offset is an angular offset and / or a translational offset between the impeller axis and the axis of rotational symmetry.

9. A macerator comprising:P605579PC00 a maceration chamber comprising a flat base, wherein the base has a geometric centre; an impeller adjacent the base and configured to rotate about an impeller axis; and a drain inlet adjacent the impeller, wherein the impeller axis is offset from the geometric centre of the base.

10. A macerator according to claim 9, further comprising a sidewall upstanding from the base to define a conical volume comprising an axis of rotational symmetry, wherein the impeller axis is offset from the axis of rotational symmetry, optionally wherein the offset is an angular offset and / or a translational offset between the impeller axis and the axis of rotational symmetry.

11. A macerator according to claim 9, further comprising a sidewall upstanding from the base, wherein an edge of the impeller is adjacent the intersection between the base and a portion of the sidewall.

12. A macerator according to claim 4, or any of claims 5 to 8, or claim 11, wherein the portion of the sidewall adjacent the edge of the impeller is substantially perpendicular to the base.

13. A macerator according to claim 4, or any of claims 5 to 8, or claim 11, wherein the portion of the sidewall adjacent the edge of the impeller extends at an acute angle relative to the base, preferably wherein the angle is between 80 and 90 degrees.

14. A macerator according to any of claims 1 to 13, wherein the sidewall adjacent the impeller is curved to substantially match a portion of the circumference of the impeller.

15. A macerator according to any of claims 1 to 14, wherein the sidewall defines a sidewall recess adjacent the base, and wherein a portion of the periphery of the impeller is arranged to rotate within the sidewall recess.

16. A macerator according to any preceding claim, wherein the maceration chamber is inclined relative the vertical.

17. A macerator according to any preceding claim, wherein the base is elliptical.P605579PC0018. A macerator according to any preceding claim, wherein the base comprises a base recess and wherein the impeller is arranged to rotate within the base recess.

19. A macerator according to claim 18, wherein the base recess comprises cutting apertures about the periphery of the base recess, the cutting apertures suitable for cutting solid particulates and through which macerated waste is able to flow from the maceration chamber to a drain.

20. A macerator according to any preceding claim, wherein the impeller comprises at least one projection extending into the maceration chamber and arranged to rotate with the impeller about the impeller axis.

21. A macerator according to any preceding claim, wherein the base is inclined relative to the horizontal.

22. A macerator according to claim 21, wherein a portion of the periphery of the impeller is located at a lowermost region of the base.

23. A macerator according to any preceding claim, further comprising a drain inlet, wherein the drain inlet is located below a lowermost region of the base.

24. A macerator according to any preceding claim, wherein the maceration chamber further comprises an opening at a top of the maceration chamber; and an openable lid for covering the opening in the top of the maceration chamber, wherein the lid is openable to provide user access to insert maceratable materials into the maceration chamber, optionally wherein the openable lid has a pivotal connection to a body of the macerator.

25. A macerator according to any of claims 1 to 23, wherein the maceration chamber further comprises an inlet at a top of the maceration chamber, and wherein the maceration chamber is couplable in-line within a drainage system.

26. A macerator according to any preceding claim, wherein the macerator is configured to process healthcare waste including incontinence briefs, pads, pans, wipes, dog waste, or food waste.

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