System for separating particulates from a fluid and method

Abstract

A system 102 and method for separating particulates from a fluid. The system 102 comprises a separator 104 configured to separate particulates from a fluid. The separator 104 has a separator inlet 118

Description

The invention relates to a system for separating particulates from a fluid, and particularly, but not exclusively relates to a system for separating microfibres from a liquid, such as water, following a manufacturing or washing process. BACKGROUND Effluent from manufacturing or a treatment processes (such as dyeing or washing) of textiles typically often comprises a mixture of water and particulates in the form of microfibres, such as plastic microfibres, that have been shed by the textiles during the manufacturing or treatment process. Microfibres are defined internationally as fibres having a length of 0.3 pm to 15mm and a length to diameter ratio which is greater than 3:1 (see “Microplastics from textile sources”, ISO 4484 2:2023). The presence of microfibres in wastewater can prevent water from being re-used in a textile manufacturing facility and is harmful to life if discharged into the environment. Therefore, before being re-used or discharged into the environment, the wastewater is processed in orderto separate the microfibres from it. The microfibres themselves may then also be reused or disposed of. During manufacture of textiles, separation of the microfibres from the wastewater is typically done using settling tanks. This requires large tanks in order to temporarily store the large volume of waterthat needs to be processed. It would be desirable to use separator systems, such as filters which comprise a separating chamber having an inlet, an outlet and a filter element, such as a mesh, disposed between the inlet and the outlet and arranged to capture microfibres which are larger than a predetermined size. However, a problem associated with using the relatively small mesh sizes required to capture microfibres is that the accumulation of microfibres on the mesh can be rapid which then Leads to a reduction of the rate of flow rate through the filter or else requires an increase in fluid pressure in order to maintain a desired flow rate through the filter. A filter must therefore be cleaned regularly in order to remove the microfibres. Typically, the filter is removed from a separator in order to dispose of the accumulated microfibres. Alternatively, operation of a separator is paused so that the filter can be ‘backwashed’ by reversing the flow of liquid through the filter and draining the liquid with the collected microfibres back through the filter inlet. Both of these methods are time consuming and inconvenient. Consequently, use of such separators having filters is avoided on the basis that they are unsuitable. Therefore, there exists need for an improved system for removing particulates, such as microfibres, from a fluid. STATEMENT OF INVENTION The invention relates to a system for separating particulates from a fluid, the system comprising: a separator configured to separate particulates from a fluid, the separator having a separator inlet, a fluids outlet through which fluid from which particulates have been separated is discharged from the separator, and a particulates outlet through which particulates separated from the fluid are discharged from the separator. According to a first aspect of the invention there is provided a system for separating particulates from a fluid, the system comprising a separator configured to separate particulates from a fluid, the separator having a separator inlet, a fluids outlet through which fluid from which particulates have been separated is discharged from the separator, and a particulates outlet through which particulates separated from the fluid are discharged from the separator, and a regulator arrangement configured to regulate flow of fluid through the particulates outlet such that particulates are selectively flushed from the separator through the particulates outlet. The invention is suitable for removing particulates from a fluid, such as Liquid, in manufacturing or a treatment processes (such as dyeing or washing) of textiles, commercial and domestic laundry applications, municipal wastewater treatment plants, and other wastewater effluent applications that require separation of particulates from a fluid, such as a liquid. The regulator arrangement acts as a flow controller configured to control the flow of fluid in which particulates are entrained through the particulates outlet. The system may therefore have a first mode of operation in which solid particulates are flushed through the particulates outlet and a second mode of operation in which solid particulates are prevented from being flushed through the particulates outlet. Flushing may be done during operation of the separator using the influent mixture of particulates and fluid, or by supplying a flushing fluid to the separator. The influent mixture may be supplied from a gravity drain system, such as from a textile processing facility, or from a pump, such as a drainage pump of a washing machine or a pump used to transfer water from a collecting or equalisation tank. Operation of the separator may cease so that flushing can be carried out independently. The regulator arrangement may comprise a valve downstream of the particulates outlet (e.g. a float valve), or downstream of the fluids outlet (e.g. a control valve configured to apply a back pressure at the fluids outlet thereby increasing a pressure within the separator) or by increasing flow rate and / or pressure at the separator inlet to create a surge flow. Meaning of terminology In the context of the claimed invention, the following terms mean the following: “flush” means the use of a fluid to convey something else, such as particulates, for example by entraining particulates along with the fluid. “particulate” means a small discrete mass of solid or liquid matter that may be individually dispersed in a fluid. The term “particulates” may refer to a collection of particulates which have agglomerated to form a combined or tangled mass. Optionally, the regulator arrangement has a first configuration in which flow of fluid through the particulates outlet is restricted and a second configuration in which particulates are flushed by a fluid through the particulates outlet. Optionally, the regulator arrangement is configured to regulate the flow of fluid from the separator through the particulates outlet independently of flow from the separator through the fluids outlet. Optionally, the regulator arrangement is configured to restrict flow of fluid from the separator through the particulates outlet based on a predetermined condition. Optionally, the predetermined condition is that the pressure at the particulates outlet is not less than a threshold pressure. The threshold pressure may be a predetermined pressure, such as a pressure at which a fluid is supplied to the separator inlet. Optionally, the threshold pressure is the pressure at the separator inlet. Optionally, the predetermined condition is that the volume of fluid through the particulates outlet over a set period is not Less than a predetermined volume. Optionally, the regulator arrangement is configured to selectively flush particulates from the separator through the particulates outlet by varying a pressure at the particulates outlet. Optionally, the regulator arrangement comprises a valve arrangement having a closed configuration in which flow of fluid through the particulates outlet is restricted and an open configuration in which particulates are flushed by a fluid through the particulates outlet. Restriction may include a significant reduction even if flow through the particulates outlet is not entirely stopped. This may provide the benefit of the invention even though flow is not prevented entirely. However, it is preferable that flow through the particulates outlet is prevented when a valve is in the closed configuration. Optionally, the valve arrangement is a pressure-activated valve arrangement that is configured to move into the closed configuration when a pressure at the particulates outlet exceeds a threshold pressure. Optionally, the valve arrangement comprises a venting arrangement arranged to vent air from the collector, wherein the venting arrangement has an open configuration in which fluid can be vented from the collector through the venting arrangement and a closed configuration in which venting of fluid from the collector through the venting arrangement is prevented. Optionally, the valve is disposed in the flow path from the separator to the collector. Optionally, the regulator arrangement comprises a pump arrangement configured to varya pressure at the particulates outlet. Optionally, the pump is disposed in the flow path from the separator to the collector. Optionally, the system further comprises a collector having a collector inlet arranged to receive particulates discharged from the separator through the particulates outlet. Optionally, the collector comprises a collection chamber configured to receive particulates discharged from the separator through the particulates outlet. Optionally, the regulator arrangement is configured to restrict flow of fluid from the separator through the particulates outlet when the volume of a Liquid within the collection chamber reaches a predetermined volume. Optionally, the collector has a collector fluids outlet and a filter element disposed between the collector inlet and the collector fluids outlet, the filter element is arranged to collect particulates greater than a predetermined size. The predetermined size may be a second predetermined size which is greater than a first predetermined size of particulates separated from the fluid by the separator. The filter element may comprise a filter mesh having a mesh size which is not Less than 250 pm, for example a mesh size which is not Less than 400 pm. The mesh size may be in the range 250 pm to 5000 pm, for example in the range 400 pm to 3000 pm. Optionally, the collector inlet is in fluid communication with the particulates outlet via a conduit, the conduit is configured to inhibit flow from the collection chamber to the separator via the conduit during operation. Optionally, the particulates outlet is in open fluid communication with the collector inlet. A particulates outlet which is in open fluid communication with the collector inlet is not provided with a means of closing the particulates outlet (i.e. no mechanical element or moving parts are provided to occlude or otherwise block the particulates outlet). Optionally, the separator comprises a filter element disposed between the separator inlet and the separator fluids outlet and configured to separate particulates from a fluid which are greater than a first predetermined size. The first predetermined size may be the size of microplastics or microfibres, for example, microplastics having a size in the range 0.1 pm to 5mm, and / or microfibres having a Length in the range 0.3 pm to 15mm and a length to diameter ratio which is greater than 3:1. The filter element may comprise a mesh having a mesh size in the range 5 to 250 pm, typically a mesh size in the range 10 to 100 pm. The mesh size may be in the range 5 to 25 pm, 25-50 pm, 50-100 pm, or 100-250 pm or in any contiguous combination of 2 or 3 of these ranges. Optionally, the filter element is arranged such that fluid which is selectively flushed from the separator through the particulates outlet bypasses the filter element. Optionally, the separator comprising a separator chamber and the filter element divides the separator chamber into an unfiltered region and a filtered region, wherein the separator inlet is arranged to supply fluid to the unfiltered region, the fluids outlet is arranged to discharge fluid from the filtered region and the particulates outlet is arranged to discharge fluid and particulates from the unfiltered region. Optionally, the separator chamber has an outer region and an inner region, the separator inlet is arranged to open into the outer region, the fluids outlet is arranged to open from the inner region and the particulates outlet is arranged to discharge fluid from the outer region, wherein the filter element is disposed between the outer region and the inner region of the separator chamber. Optionally, the system is configured such that, in use, a fluid mixture containing particulates supplied through the separator inlet into the separator is discharged through the particulates outlet in order to flush particulates from the separator through the particulates outlet. Optionally, the system comprises a pump arranged to pump a fluid through the separator inlet into the separator. Optionally, the pump is disposed upstream of the separator inlet. According to a second aspect of the invention there is provided a method of separating particulates from a fluid using a system in accordance with anyone of the preceding claims, the method comprising the steps: supplying a mixture comprising a fluid and particulates to the separator inlet; discharging a fluid from which particulates have been separated through the fluids outlet; regulating the flow of fluid through the particulates outlet using the regulator arrangement in order to selectively flush particulates from the separator through the particulates outlet. Optionally, the step of regulating the flow of fluid through the particulates outlet comprises regulating a pressure at the particulates outlet. Optionally, a fluid supplied via a separator inlet is used to flush particulates through the particulates outlet. According to a third aspect of the invention there is provided a system for separating particulates from a fluid, the system comprising: a first separator configured to separate particulates from a fluid, the first separator having a first separator inlet, a first separator fluid outlet through which fluid from which particulates have been separated is discharged from the separator, and a particulates outlet arranged to provide an outlet through which particulates separated from the fluid are discharged from the first separator; and a second separator configured to separate particulates from a fluid, the second separator having a second separator inlet arranged to receive particulates discharged through the particulates outlet of the first separator, a second separator fluid outlet through which fluid from which particulates have been separated is discharged from the separator, the second separator fluid outlet is arranged in fluid communication with the first separator such that fluid discharged through the second separator fluid outlet is returned to the first separator. In embodiments described in the specification, the second separator is a collector assembly configured to both separate and collect particulates from an influent mixture. Optionally, the first separator is configured to separate particulates from the fluid which are greater than a first predetermined size and the second separator is configured to separate particulates from the fluid which are greater than a second predetermined size, wherein first predetermined size is smaller than the second predetermined size. The first predetermined size may be the size of microplastics or microfibres, for example, microplastics having a size in the range 0.1 pm to 5mm, and / or microfibres having a Length in the range 0.3 pm to 15mm and a Length to diameter ratio which is greater than 3:1. Optionally, the second separator is configured to collect, and temporarily store, particulates separated by the second separator. Optionally, the second separator is arranged with respect to the first separator such that a liquid within the second separator drains under gravity to the first separator via the second separator fluid outlet. Optionally, a valve is disposed between the second separator and the first separator to control the discharge of fluid from the second separator to the first separator through the second separator fluid outlet. Optionally, the valve is a one-way valve arranged to prevent flow from the first separator to the second separator through the second separator outlet. Optionally, the second separator comprises a venting arrangement arranged to vent air from the second separator, wherein the venting arrangement has an open configuration in which fluid can be vented from the second separator through the venting arrangement and a closed configuration in which venting of fluid from the second separator through the venting arrangement is prevented. Optionally, the separator comprising a separator chamber and a filter element which divides the separator chamber into an unfiltered region and a filtered region, wherein the separator inlet is arranged to supply fluid to the unfiltered region, the fluids outlet is arranged to discharge fluid from the filtered region and the particulates outlet is arranged to discharge fluid and particulates from the unfiltered region. Optionally, the second separator fluid outlet is arranged in fluid communication with the first separator such that fluid returned to the unfiltered region of the first separator. Optionally, the second separator comprises a collecting chamber and a filter element which divides the collecting chamber into an unfiltered region and a filtered region, wherein the second separator inlet is arranged to supply fluid to the unfiltered region and the second separator fluids outlet is arranged to discharge fluid from the filtered region. According to a fourth aspect of the invention there is provided a system for separating solid particulates from a fluid, the system comprising: a separator configured to separate solid particulates from a fluid, the separator having a separator inlet, a fluids outlet through which fluid from which particulates have been separated is discharged from the separator, and a particulates outlet through which particulates separated from the fluid are discharged from the separator; and a collector having a collector inlet arranged to receive particulates discharged from the separator through the particulates outlet, wherein the system is configured to selectively discharge solid particulates from the separator through the solids outlet to the collector. Optional features of each of the first, second, third and fourth aspects of the invention may be combined with the other of the first, second, third and fourth aspects of the invention and optional features thereof. Aspects of the invention provide a system for separating particulates from a fluid in which particulates separated from a fluid by a separator are selectively discharged from the separator, for example into a collector, so as to reduce the quantity of particulates within the separator which would otherwise be detrimentalto operation ofthe separator. Furthermore, aspects of the invention provide a system for separating particulates from a fluid in which separated particulates can be removed from a separator without having to cease operation of the separator and / or without having to gain access to the separator, for example to clean a filter element. Aspects of the invention provide a system for separating particulates from a fluid in which particulates separated from a fluid by a separator can be collected and dewatered effectively without adversely affecting operation of a separator. DRAWINGS Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings where like parts are provided with corresponding reference numerals and in which: Figure 1 is a perspective view of a system for separating particulates from a fluid; Figure 2 is a perspective view of the system shown in Figure 1 from a different perspective; Figure 3 is a partial perspective view of a portion of the system shown in Figure 1 comprising a separator; Figure 4 is a partial perspective view of a portion of the system shown in Figure 1 comprising a regulator arrangement; Figure 5 is a sectional view of the system shown in Figure 1; Figure 6 is a sectional view of the system shown in Figure 1; Figure 7 is a schematic representation of the system shown in Figure 1; Figure 8 flowchart illustrating steps of a method of operating the system shown in Figure 1; Figures 9a to 9e are schematic representations of Liquid Levels in the system shown in Figure 1 during operation; Figure 10 is a schematic representation of a factory Layout illustrating optional arrangements; Figure 11 a is a schematic representation of an effluent treatment plant; Figure 11 b is a schematic representation of a further effluent treatment plant; Figure 12 is a schematic representation of a factory facility; Figure 13 is a schematic representation of a washing machine; Figure 14 is a schematic representation of a tumble drier; Figures 15a to 15c are schematic representations of different configurations of a system for separating particulates from a fluid; Figure 16 is a schematic representation of a particular configuration of a system for separating particulates from a fluid; Figure 17 is a schematic representation of a particular configuration of a system for separating particulates from a fluid; Figure 18 is a schematic representation of a particular configuration of a system for separating particulates from a fluid; 5 Figure 19 is a schematic representation of a particular configuration of a system for separating particulates from a fluid; Figure 20 is a schematic representation of a particular configuration of a system for separating particulates from a fluid; Figure 21 is a schematic representation of a particular configuration of a system for 10 separating particulates from a fluid, and Figure 22 is a schematic representation of a particular configuration of a system for separating particulates from a fluid. DETAILED DESCRIPTION Referring to Figures 1 to 7, there is provided a system 102 for separating particulates from a fluid, particularly for separating microplastics from a Liquid, such as water. The system 102 comprises a separator 104, a collector assembly 106, a return conduit 108 and a regeneration pump 110. Separator The separator 104 comprises a separator housing 112 which defines a separating chamber 114andasump 116 disposed below the separating chamber 114. The separating chamber 114 is generally cylindrical and defines a separator axis X. The separator 104 has a primary separator inlet 118 through which a mixture of a fluid and particulates to be separated enters the separator 104, a collector return inlet 120, a separator fluids outlet 122 (referenced in Figure 2) through which fluid from which particulates have been separated is discharged from the separator 104, a regeneration fluids outlet 124 for supplying a regeneration system (described Later) with fluid from which particulates have been separated, and a separator particulates outlet 126 through which particulates that have been separated from the fluid are discharged from the separator 104. A filter element 128 is disposed within the separating chamber 114 and arranged to divide the separating chamber 114 into an annular radially outer‘dirty’ (unfiltered) region 114a and a cylindrical radially inner‘clean’ (filtered) region 114b. The filter element 128 is configured to separate particulates from a flowthrough it which are greater than a first predetermined size. In the embodiment shown, the filter element is configured to separate particulates which are microplastics, and particularly plastic microfibres. In the embodiment shown, the filter element 128 comprises a cylindrical frame 130 having apertures 130a arranged circumferentially about the filter element 128 and a filter mesh 130b (depicted in Figure 7, but not shown in Figures 1 to 6) arranged to occlude the apertures 130a. The filter mesh 130b has a mesh size which is selected in order to filter microfibres from an influent mixture of water and particulates. The term filter mesh is used herein to denote any form of filter or (semi) permeable material including a mesh or membrane filter which is configured to block particulates such as microfibers or other microplastics based on the size of the contaminants. For example, the filter mesh 130b may have a mesh size in the range 5 to 250 pm, typically a mesh size in the range 10 to 100 pm. The mesh size may be in the range 5 to 25 pm, 25-50 pm, 50-100 pm, or 100-250 pm, or in any contiguous combination of 2 or 3 of these ranges. In practice a given mesh size is capable of blocking (filtering out) contaminants which are similar or slightly smaller in size than the mesh size of the filter. Forexample, a mesh aperture of 80 pm may stop up to 99% of microfibers of 25 pm in size. This is because, once particulates begin to accumulate on a mesh they, in turn, act as an obstruction for further particulates and so can form a barrier that blocks particulates that are significantly smaller than the particulates blocked by the mesh itself. A filter mesh having a relatively small mesh size is good for removing small particulates such as microplastics, but tends to become blocked more rapidly leading to a decrease in the flow rate through the filter overall for a specific pressure, and hence overall reduction in performance. The housing 112 defines an inlet port 118a which opens into the annular radially outer region 114a of the separating chamber 114 and an inlet conduit 118b which extends from the inlet 118 to the inlet port 118a. The inlet conduit 118b is arranged to direct a mixture to be separated through the inlet port 118b into the annular radially outer region 114a of the separating chamber 114 in a radially inward direction. A guide vane 132 is disposed within the separating chamber 114 adjacent the separator inlet 118. The guide vane 132 extends from the housing 112 to the filter element 128 and is arranged to direct flow through the separator inlet 118 in a circumferential direction within the annular radially outer chamber 114a. A filter regeneration system 134 (see Figures 3 and 5 for reference) is disposed within the cylindrical radially inner region 114b of the separating chamber 114. The regeneration system 134 comprises a rotor 136 and a stator 137 about which the rotor 136 is arranged to rotate. The rotor 136 has a cylindrical rotor body 138 into which washing fluid is supplied via the stator 137 and opposing spray nozzles 140a, 140b that extend tangentially from the rotor body 138 and are configured to direct a jet of fluid against the radially inner surface of the filter element 128 in order to backwash / clean the filter mesh 130b of the filter element 128. The housing 112 defines a particulates outlet port 126a which opens from the annular radially outer region 114a of the separating chamber 114. The outlet port 126a is circumferentially spaced from the inlet port 118a. An outlet conduit 126b is arranged to direct flow through the outlet port 126a to the particulates outlet 126. The sump 116 is disposed immediately below the cylindrical radially inner region 114b so as to receive fluid that passes from the outer annular chamber 114a through the cylindrical filter element 126. In the embodiment shown, the sump 116 has a diameter which is the same as the diameter of the filter element 128. The sump 116 is defined by a radially outer wall of the housing 112 and a radially inner wall of the housing 112 having a u-shaped cross-section which defines an external cavity through which a conduit (not shown) which connects the regeneration pump 110 to a spigot 137a of the stator 137 for supplying fluid to the regeneration system 134 is received. The separator fluids outlet 122 is provided ata region of the radially outer wall of the housing 112 which forms an upper portion of the sump 116 — this is the region immediately below the annular radially outer chamber 114a. Collector Assembly The collector assembly 106 comprises a collector housing 142 which defines an elongate collecting chamber 144. The collector assembly 106 has a collector inlet 146, a collector fluids outlet 148 and a regulator arrangement 150. A filter element 152 (depicted in Figure 7, but not shown in Figures 1 to 6) is arranged within the collecting chamber 144 such that the filter element 152 divides the collecting chamber 144 into an upper region 144a and a Lower region 144b. In the embodiment shown, the filter element 152 is in the form of a planar mesh that is configured to separate particulates from a flow through it which are greater than a second predetermined size. The filter element 152 extends horizontally within the collecting chamber 144. The relative height of the filter element 152 with respect to the filter element 128 of the separator 104is important in order to ensure dewatering of particulates which collect on the filter elements 152, as is explained with respect to operation of the system 102. The filter element 152 is, therefore, arranged such that it extends in a plane which is higher than the Lower edge of the filter element 128 of the separator 104. The filter element 152 of the collector assembly 106 is configured to separate particulates having a second predetermined size which is Larger than the first predetermined size separated by the filter element 128 of the separator 104. In particular, the filter element 152 is configured to separate clumps of microfibres or agglomerated particulates that are discharged by the separator 104 into the collector 106. The filter element 152 is primarily configured to block these so that they are retained in the collector 106. The filter element 152 may com prise a filter mesh havinga mesh size which is not Lessthan250 pm, forexample a mesh size which is not less than 400 pm. The mesh size may be in the range 250 pm to 5000 pm, for example in the range 400 pm to 3000 pm. In the embodiment shown, the filter element 152 is a mesh havinga mesh size which is 1410pm. The collector housing 142 defines a collector inlet port 154 which is disposed at one end of the collecting chamber 144 such that it opens into the upper region 144a of the collecting chamber 144 above the filter element 152. A collector inlet conduit 156 extends from the collector inlet 146 to the collector inlet port 154. The collector inlet port 154 is disposed higher than the collector inlet 146 and the collector inlet conduit 156 is inclined upwardly from the collector inlet 146 to the collector inlet port 154. The collector inlet conduit 156 may be considered to act as a one-way valve arranged to allow flow from the separator 104 to the collector assembly 106, as depicted in Figure 7. In alternative embodiments, the collector inlet conduit 156 may be provided with a one-way valve arranged to allow flow from the separator 104 to the collector assembly 106 in which case the collector inlet port 154 need not be disposed higher that the separator particulates outlet 126 and the collector inlet conduit 156 need not be inclined upwardly. The collector housing 142 further defines a collector outlet port 158 which is disposed such that it opens from the lower region 144b of the collecting chamber 144 below the filter element 152. An outlet conduit 160 extends from the collector outlet port 158 to the collector fluids outlet 148. The collector housing 142 also defines a vent port 162 which is disposed at the end of the collecting chamber 144 opposite the inlet port 154 and opens from the upper region 144a of the collecting chamber 144 above the filter element 152. The vent port 162 is at a Lower height than the inlet port 154 such that liquid flows through the vent port 162 before the level of a Liquid within the collecting chamber 144 reaches the inlet port 154. A vent conduit 164 extends from the vent port 162 to the regulator arrangement 150. In the embodiment shown, the regulator arrangement 150 comprises a vent valve having a ball 166 disposed within a vent chamber 168 provided with a vent outlet 170. The regulator arrangement 150 has an open configuration in which the ball 166 is spaced from the vent outlet 170 such that that air can expelled from the collecting chamber 144 through the vent outlet 170 and a closed configuration in which the ball 166 blocks (occludes) the vent outlet 170 such that expulsion of air from the collecting chamber 144 through the vent outlet 170 is prevented. The regulator arrangement 150 is configured to close when the Liquid Level within the collecting chamber 144 reaches a predetermined Level. The predetermined Level is a level above the filter element 152, preferably above the vent port 154, and below the inlet port 154. The regulator arrangement 150 may be connected to an overflow such as a bypass conduit or a return to a collecting tank upstream of the system 102 so that in the event that the venting arrangement 154 fails, fluid does not leak from the system 102. In other embodiments, alternative configurations of a regulator arrangement 1 may be used, for example alternative types of vent valves or a vertical tube, electronically activated valve, or a mechanically activated valve. In some embodiments, a vent is not required. The primary function of the collector assembly 106 in the described embodiment is to collect particulates discharged from the separator 104 for subsequent processing. A further function of the collector assembly 106 is to dewater the collected particulates by separating the particulates from the water used to flush the particulates from the separator 104. The collector assembly 106 can therefore be regarded a second separator for separating particulates from a concentrated mixture of particulates and a fluid. In alternative embodiments, the collector arrangement 106 could be formed integrally with the separator 104. The collector arrangement 106 could be detachably connected to the separator 104 such that the collector assembly 106 can be detached for emptying. In alternative embodiments, other equipment could be disposed between the separator 104 and the collector assembly 106. Return Conduit The return conduit 108 connects the collector fluids outlet 148 to the recirculation separator inlet 120 such that the collector assembly 106 is in fluid communication with the separator 104. A non-return valve 171 (depicted in Figure 7, but not shown in Figures 1 to 6) is disposed within the return conduit 108 and arranged to prevent flow from the separator 104 to the collector assembly 106 along the return conduit 108. In an alternative embodiment, the return conduit 108 could connect the fluids outlet 148 to the separator fluids inlet 118, or upstream of the separator fluids inlet, such that fluid is returned via the separator fluids inlet 118. Operation Operation of the system 102 will be described with reference to several phases of operation: i) an initial separation phase P1, ii) a filter regeneration phase P2, iii) an initial drain down / dewatering phase P3, iv) a flushing and subsequent separation phase P4, and v) a subsequent dewatering phase P5. A flow chart depicting these phases is provided in Figure 8. i) Initial separation phase PI During an initial separation phase P1, a mixture of particulates and a Liquid, such as a mixture of water and microfibres, is supplied to the separator inlet 118. For example, the mixture of particulates and a liquid may be an effluent from a textile processing facility or a washing machine, such as a domestic washing machine or one or more commercial laundry machines, comprising plastic microfibresand water, is supplied to the separator inlet 118 as part of a drainage cycle. The mixture flows from the separator inlet 118 along the inlet conduit 118b and through the inlet port 118a into the radially outer region 114a of the separating chamber 114. The guide vane 132 directs the mixture in a circumferential direction of the separating chamber 114 around the radially outer surface of the filter element 128. As the mixture moves around the separating chamber 114, the water passes through the filter mesh 130b and into the sump 116 from which it is then discharged through the separator fluids outlet 122. It will be appreciated that the fluid discharged through the fluids outlet 122 will have both the fluid and particulates which are smaller than the predetermined size filtered by the filter element 128. The fluid will not, however, have particulates greater than the predetermined size filtered by the filter element 128. The fluid outlet is therefore the sole outlet for fluid from which particulates having the predetermined size have been removed. On initiation of the initial separation phase, the collecting chamber 144 of the collector assembly 106 is empty. However, as the separating chamber 114 is flooded, at Least some of the mixture flows out of the particulates outlet 126 into the collector inlet conduit 156. It will be appreciated that although a mixture of fluid and particulates may flow out of the particulates outlet 126, the particulates outlet 126 is sole means of discharge of filtered particulates (i.e. particulates greater than the predetermined size filtered by the filter element 128) from the separator 104. The pressure of the mixture within the separator 104 causes the level of water within the collector inlet conduit 156 to rise until it reaches the collector inlet port 154 where it flows into the upper region 144a of the collecting chamber 144 and begins to fill the collecting chamber 144, as shown in Figure 9a. As the mixture flows downwardly through the filter element 152 into the lower region 144b of the collection chamber 144, particulates are blocked by the filter element 152. It will be appreciated that during the initial separation phase, the constitution and concentration of particulates and fluids is substantially the same as the constitution and concentration of particulates and fluid entering the separator 104. Therefore, although some Larger particulates will be blocked by the filter element 152, the amount will not be substantial. The filtered water initially flows from the lower region 144b of the collecting chamber 144 through the collector outlet port 158 and returns to the separating chamber 114 by flowing along the outlet conduit 160 through the non-return valve to the collector return inlet 120. The non-return valve prevents reverse flow of water from the separating chamber 114 into the collecting chamber 144 via the return conduit 108 that could occur while the pressure in the separating chamber 114 is greater than the pressure in the collecting chamber 144. Once the pressure of the Liquid within the collecting chamber 144 and the separating chamber 114 has equalised via the return conduit 108, flow out of the collecting chamber 144 along the return conduit 108 ceases and the Level of the fluid and particulates mixture within the collecting chamber 144 begins to rise within the collecting chamber 144. The level of the fluid and particulates mixture within the collecting chamber 144 continues to increase within the collecting chamber 144 above the Level of the filter element 152. Even as the collecting chamber 144 becomes flooded, particulates blocked by the filter element 152 are retained in the upper region 144a of the collecting chamber 144 above the filter element 152. As the water level reaches the level of the vent port 162, the vent conduit 164 and the vent chamber 168 begins to flood. This causes the ball 166, which is buoyant, to rise and block the vent outlet 170 such that the regulator arrangement 150 is moved from its open configuration to its closed configuration. Once the vent outlet 170 is blocked (i.e. the regulator arrangement 150 is in its closed configuration), the collecting chamber 144 becomes flooded, as shown in Figure 9b, and any air remaining within the chamber is compressed until the pressure within the collecting chamber 144 equals the pressure within the separating chamber 114. When the pressures within the collecting chamber 144 and the separating chamber 114 at the particulates outlet 126 are equal, water can no Longer flow from the separator 104 into the collecting chamber 144 and so flow from the separator 104 into the collector assembly 106 ceases. Flow through the separator 104, however, continues such that particulates are separated from the water by the filter mesh 130b and filtered water passes through the sump 116 and out of the separator fluids outlet 122. Flow in the vicinity of the separator particulates outlet 126 stagnates which allows particulates that have been carried around the annular radially outer region 114a of the separating chamber 114 to accumulate in the vicinity of the separator particulates outlet 126. The particulates will tend to agglomerate into clumps, for example tangled bundles of microfibres. Particulates blocked by the filter mesh 130b are retained in the radially outer region 114a of the separating chamber 114. At Least some of these particulates begin to accumulate on the outer surface of the filter mesh 130b about its circumference. As flow of the mixture through the separator 104 continues, a Layer of filtered particulates builds up on the outer surface of the filter mesh 130b. This can lead to an increase in the efficiency of the filter mesh 130b since finer particulates are captured, but also Leads to a greater restriction of flow through the filter mesh 130b which reduces flow rate through the separator 104, and hence its overall performance, or otherwise requires an increase in the upstream pressure (i.e. pressure at the separator inlet 118) to overcome the greater restriction. It will be appreciated that the size of particulates blocked by the filter mesh 130b may be significantly smaller than the mesh size. This is because flow direction of the fluid arriving at the filter mesh 130b may not be aligned with the direction of flowthrough the filter mesh 130b and so the effective mesh size may be significantly smaller. In addition, accumulated particulates on the mesh will block further particulates and so act as a filter themselves. The more particulates accumulate, the smaller the effective mesh size. Typically, the separator 104 may be operated continuously over a drainage cycle before the flow restriction becomes too great and particulates need to be removed from the filter mesh 130a. ii) Filter regeneration phase P2 In order to remove accumulated particulates from the filter mesh 130b (i.e. clean the filter mesh 130b) and so regenerate the filter element 128, the regeneration system 134 is operated by activating the regeneration pump 110. When activated, the regeneration pump 110 pumps filtered water from the sump 116 to the rotor 136 and through each spray nozzle 136a, 136b against the radially inner surface of the filter element 128. The sprayed water dislodges accumulated particulates from the outer surface of the mesh causing them to fall back into the radially outer region 114a of the separating chamber 114. The tangential arrangement of the spray nozzles 136a, 136b means that a reactionary force on each spray nozzle as the water is sprayed against the filter element 128 causes the rotor 136 to rotate about its axis. The two spray nozzles 136a, 136b therefore sweep around the entire circumferential extent of the filter element 128 thereby directing a spray through the filter mesh 130b in a generally radially outward direction thereby removing the Layer of particulates and so cleaning the entire filter element 128. Following cleaning of the filter mesh 130b by the regeneration system 134, the particulates are swept by the flow around the outer chamber 114a of the separating chamber 114 towards the particulates outlet 126 where they accumulate. The particulates will again tend to agglomerate into clumps, for example tangled bundles of microfibres. It will be appreciated that the filter mesh 130b maybe cleaned using the regeneration system 134 during a separation phase while a flow of a mixture through the separator 104 is maintained without having to stop the separation process. However, the flow through the separator 104 could also be stopped prior to operating the regeneration system 134. This may be effective if a Large quantity of particulates has accumulated on the filter mesh 130b. Where regeneration of the filter element 128 is carried out between drainage cycles, the particulates settle in the radially outer region 114a until a subsequent drainage cycle. In alternative embodiments, the rotor 136 may be driven by a motor or other means instead or in addition to a reactionary force. Hi) Initial drain down / dewateringphase P3 When flow into the separator 104 is stopped (for example at the end of a drainage cycle or because the quantity of particulates within the outer region 114a of the separator chamber 114 is having a significant adverse effect on filtration) water drains out of the separating chamber 114 through the filter element 128 into the sump 116 and out of the separator fluids outlet 122. Water that has collected in the collector assembly 106 drains from the collecting chamber 144 through the return conduit 108 and into the separator 104. As water drains from the collecting chamber 144, the small quantity of particulates filtered by the filter element 152 are retained by the filter element 152 and so stored by the collector assembly 106 for subsequent processing. Water from the collector assembly 106 that has drained into the separator 104 drains through thefilter element 128 into the sump 116 and out of the separator fluids outlet 122. At the end of the drain down phase, substantially all water has drained from the collecting chamber 144 and the annular radially outer ‘dirty’ region 114a of the separating chamber 114, as shown in Figure 9c. Any particulates which have passed through the collector assembly 106, and which are greater than the first predetermined size, are separated from the water by the filter element 128 before the fluid is discharged from the separator 104 through the fluids outlet 122. Therefore, only water which has been filtered to the required amount is discharged from the separator 104. Water below the level of the fluids outlet 122 is retained in the sump 116 and may be used to by the filter regeneration system 134 to clean the filter element 128 between drainage cycles. iv) Flushing and subsequent separation phase P4 On initiation of the subsequent drainage cycle, a mixture is supplied to the separator inlet 118 as before. The mixture flows around the radially outer region 114a of the separating chamber 114 to the separator particulates outlet 126. As it does so, the particulates that have settled within the radially outer region 114a are entrained by the mixture towards the particulates outlet 126. Since the mixture that had previously flooded the collecting chamber 144 has drained away and the collecting chamber 144 is open to atmosphere via the vent outlet 170, there is no ‘back pressure’ being applied at the particulates outlet 126 (i.e. the pressure in the collecting chamber 144 is Lower than the pressure of the mixture) and so the mixture flushes the settled particulates together with particulates that previously accumulated inthe vicinity of the particulates outlet 126 through the particulates outlet 126, up the collector inlet conduit 156 and into the collecting chamber 144. These particulates then collect on the filter element 152, as shown in Figure 9d. This concentrated mixture has a much higher concentration of particulates than the mixture flowing into the separator 104. A significantly smaller volume of fluid therefore has to be discharged from the separator 104 into the collector assembly 106 for collection and / or processing than would be required if the mixture flowing into the separator 104 were discharged directly into the collector assembly 106. The particulates, such as microfibres, have agglomerated and so a Large proportion of the particulates are blocked by the coarser filter element 152 in the collector 106. Using the coarser mesh helps reduce the restriction provided by the mesh and can also help reduce the frequency by which a mesh needs to be cleaned. Once the particulates that had accumulated in the separator 104 are flushed into the collector assembly 106, operation continues as previously until the collecting chamber 144 is flooded and flow through the particulates outlet 126 ceases, as described previously. At this stage, the flow at the particulates outlet 126 has stagnated, creating a quiescent region in the vicinity of the particulates outlet 126. Flow through the separator 104, however, continues from the separator inlet 114 through the filter element 128 and the separator fluids outlet 116 in order to separate particulates from the water. v) Subsequent dewatering phase P5 Once the drainage cycle is complete, water drains out of the separator 104 and the collector assembly 106 as described with respect to the initial drain down / dewatering phase P3. This results in water draining from all of the particulates that have collected in the collecting chamber 144, thereby dewateringthe particulates for Later disposal or processing, as shown in Figure 9e. The system 102 is able to selectively discharge particulates from the separator by flushing them through the particulates outlet 126 when required, for example when the quantity of particulate in the separator 104 has a significant detrimental effect on the overall performance ofthe separator 104 (e.g. increased flow restriction). Furthermore, the system 102 enables particulates to be discharged from the separator 104 intermittently as a mixture having a much greater concentration of particulates than the influent mixture to the separator 104. The system 102 therefore avoids the need to have access to the separator 104 for cleaning and also increase number of operations before cleaning. The regulator arrangement 150 is passive and so flushes of particulates automatically during each drainage cycle. The system is therefore able to self-regulate during operation. The system can be regenerated and flushed periodically in accordance with a predetermined cycle, such as a drainage cycle. In other embodiments, selective flushing of particulates through the particulates outlet 126 may be achieved by providing a regulator arrangement which varies a flow rate through the separator or pressure within the system, such as at the particulates outlet, for example by operating the system at a greater flow rate or greater pressure for a short period thereby causing flow of a mixture from the separator to the collector which flushes particulates into the collector. The regulator arrangement may be configured to increase the pressure of the mixture supplied to the separator or by throttling the flow of fluid from the separator. With such arrangements, the system could be operated continuously with periodic flushing. The collector 106 may be arranged so that it is easily accessible for emptying. For example, a collector 106 associated with a separator may be remote from the separator 104. The system described above with respect to Figures 1 to 7 may be used in various applications, such as domestic washing machines, industrial washing machines and / or as part of a manufacturing process for textiles. For example, the system may be used in a textile manufacturingfactory having apparatus for dyeing and finishing processes. Figure 10 is a schematic illustration of a textile manufacturing factory comprising various textile processing facilities for different types or stages of textile manufacturing. Figure 10 is provided for illustration purposes and does not necessarily reflect an actual manufacturing factory. The Layout, arrangement of each facility and / or a factory as a whole may be configured in accordance with specific requirements and the described example should not be considered limiting. The textile processing factory 1002 comprises a first facility 1004, a second facility 1006, a third facility 1008 and a fourth facility 1010. The first facility 1004 may, for example, be a facility for dyeing comprising a first dyeing apparatus 1004a, a second dyeing apparatus 1004b, and a third dyeing apparatus 1004c. An effluent outlet of each dyeing apparatus 1004a, 1004b, 1004c is connected to the separator inlet of a respective system 102a, 102b, 102c for separating particulates from a fluid. Each system 102a, 102b, 102c is connected to a common outlet from the first facility 1004. The second facility 1006 may, for example, be a facility for finishing textiles comprising a first finishing apparatus 1006a, a second finishing apparatus 1006b, and a third finishing apparatus 1006c. An effluent outlet of each finishing apparatus 1006a, 1006b, 1006c is connected to a single system 102 which then connected to a single outlet for the second facility 1006. The system 102 may comprises a tank upstream of the separator for temporarily storing effluent from the first, second and third finishing apparatus 1006a, 1006b, 1006c and a pump arranged to pump water from the tank to the separator. Water collected in the tank can then be pump at a controlled rate to the system so as to ensure that a controlled flow rate is delivered to the separator. The third facility 1008 may, for example, be a washing facility comprising a first washing apparatus 1008a and a second washing apparatus 1008b. An effluent outlet of each washing apparatus 1008a, 1008b is connected to a single outlet for the third facility 1008. The fourth facility 1010 may, for example, also be a washing facility comprising a first washing apparatus 1010a and a second washing apparatus 1010b. An effluent outlet of each washing apparatus 1010a, 1010b is connected to a single outlet for the fourth facility 1010. In the arrangement shown, the outlets of the third facility 1008 and the fourth facility 1010 are combined into a single outlet which is connected to a system 102. A return conduit 1011 from the system 102 associated with the third and fourth facilities 1008, 1001 may be provided from the system 102 to return fluid from which particulates have been removed to the third facility 1008 or any other of the facilities for which it would be suitable for use. A system 102 may be disposed between any one of the facilities described above depending on requirements. The outlets of the first and second facilities 1004,1006 and combined outlet from the system 102 for the third and fourth facilities 1008,1010 are connected to an effluent treatment plant 1012. The effluent treatment plant 1010 provides a final treatment of effluent prior to discharge into the environment. A return conduit 1013 may be provided from the effluent treatment plant 1010 in order to return treated water to one or more of the facilities of the textile processing factory 1002 for re-use. The effluent treatment plant 1012 is provided with an outlet 1014 from which treated water is discharged into the environment. The combined effluent from what are typically referred to as ‘wet’ processes may contain microfibres, salt and processing chemicals, entrained in water is discharged from 'wet' processes such as dyeing and finishing. Figure 11a is a schematic representation of a standard effluent treatment plant 1012 configured to provide filtration of particulates from water which is between 50% and 80% efficient. The effluent plant 1012 comprises an equalisation tank 1012a, a system 102, a biological treatment apparatus 1012b and a further system 102. Effluent entering the effluent treatment plant 1012 is collected in the equalisation tank 1012a in which the effluent is homogenised so that a constant effluent composition is supplied to the system 102. The effluent is supplied to the system 102 by gravity, or preferably by pumpingat a constant rate, to remove particulates having a predetermined size. Filtered water is then supplied to the biological treatment apparatus 1012b which uses biological agents and chemicals to treat the chemical components of the effluent. The water is then supplied to a further system 102 configured to remove coagulated particulates generated by the biological treatment process. The fluid is then discharged from the effluent treatment plant 1012. Figure 11b is a schematic representation of an advanced effluent treatment plant 2012 configured to provide filtration of particulates from water which is between 90% and 99.9% efficient. An advanced arrangement is typically used where high degree of purification is required, for example when water is recirculated for re-use. The effluent plant 2012 comprises an equalisation tank 2012a, a system 102, a biological treatment apparatus 2012b, a further system 102, and a re-verse osmosis apparatus 2012d. Effluent entering the effluent treatment plant 2012 is collected in the equalisation tank 2012a. The effluent is then supplied to the system 102 by gravity, or preferably by pumpingat a constant rate, to remove particulates having a predetermined size. Filtered water is then supplied to the biological treatment apparatus 2012b which uses biological agents and chemicals to treat the chemical components of the effluent. The water is then supplied to a further system 102 for removal of coagulated particulates generated by the biological treatment process. The water is then supplied to a re-verse osmosis apparatus 2012d for final treatment before being discharged from the effluent treatment plant 2012 for re-use or discharge into the environment. Figure 12 is a schematic representation of a factory facility 2004 comprising a system 102 comprising multiple separators 104 connected to a single collector 106. Each separator 104 is arranged to receive an influent mixture from a respective processing apparatus or treatment apparatus 2004a, 2004b, 2004c. Particulates separated from a fluid by each separator are discharged to a single collector 106. The collector 106 may be arranged so that it is easily accessible for emptying. Figure 13 shows a washing machine 3002 comprising a tub 3004 in which clothes to be washed are disposed and a housing 3006. The tub 3004 has a drain 3008 connected to a large object trap 3010, typically known as a penny trap, and a drain pump 3012 for draining water from the tub 3004. A system 102 is connected to the drain pump 3012 for removing particulates from the drain water prior to recirculation or discharge from the washing machine 3002 through a drain 3014. It will be appreciated that the system 102 can be located within the washing machine housing 3006 or external the washing machine housing 3006. Figure 14 shows a drier 4002 comprising a drum 4004 in which clothes to be dried are disposed and a housing 4006. The drum 4004 is connected to a Lint filter 4008 which removes large fibres from air used in the drying process. The lint filter 4008 is connected to a system 102 and a fan 4012. The fan 4012 is configured to draw air from the drum 4004 through the lint filter 4008 and the system 102. It will be appreciated that when used in a drier 4002, the float valve of the embodiment described with respect to Figure 1 to 7 would be replaced by an alternative regulator arrangement, such as a valve, in order to selectively flush particulates from the separator through the particulates outlet. Figure 15a is a schematic representation of a system 102 comprising multiple separators 104 connected to a single collector 106. Particulates separated from a fluid by each separator are discharged to a single collector 106. The arrangement may be beneficial where there are multiple sources requiring separation, but only a single collector is required and / or a collector 106 can be disposed remotely from the separators 106 so that it is easily accessible for emptying. Figure 15b is a schematic representation of a system 102 comprising multiple separators 104a, 104b, 104c connected to a single collector 106. The separators 104a, 104b, 104c are connected in series such that fluid from which particulates have been separated by an upstream separator is supplied to a downstream separator. Particulates separated from a fluid by each separator are discharged to a single collector 106, although in alternative embodiments each separator 104 could have a dedicated collector 106. The arrangement may be beneficialwhere the first separator 104a is configured to separate particulates having a first particle size, the second separator 104b is configured to separate particulates having a second particle size which is smaller than the first particle size and the third separator 104c is configured to separate particulates having a third particle size which is smaller than the second particle size. The arrangement therefor provides multiple stages of separation. Figure 15c is a schematic representation of a system 102 comprising a single separator 104 and multiple collectors 106a, 106b. The system 102 may be configured such that, when the first collector 106a is full, particulates are discharged to the second separator 104b. The first collector 106a may then be isolated, for example, by a valve arrangement and disconnected for emptying. In the following embodiments, Like parts are numbered using the same reference, but with the initial digit (e.g. “118”) replaced by a digit corresponding to the embodiment (e.g. “218”) unless otherwise specified. Figure 16 is a schematic representation of an embodiment having a bypass arrangement 272 disposed between the separator 204 and the collector 206. The bypass arrangement 272 is configured to allow a fluid mixture discharged from the separator 204 through the particulates outlet 226 to be selectively directed to the collector 206 or a drainage conduit, for example a drainage conduit 274 to which the fluids outlet 222 is connected as shown. The bypass arrangement 272 may, for example, comprise a bypass valve having a first configuration in which a fluid mixture is directed to the collector 206 and a second configuration in which a fluid mixture bypasses the collector 206. In an alternative embodiment, a bypass arrangement may be provided from the separator 204 so that should the separator 204 become blocked, a mixture can be discharged directly from the separator 204. Figure 17 is a schematic representation of an embodiment in which the collector fluids outlet 348 is connected to a drainage conduit 374 rather than a return to the separator 304. Such an embodiment maybe used where the filter element 352 of the collector 306 is configured to filter particulates having the same size as the particulates filtered by the filter element 328. With such an arrangement water from both the separator 304 and the collector 306 has been filtered to the same degree. The volume of Lower-concentration mixture filtered by the separator 304 during use is much greater than the volume of higher-concentration mixture dewatered / filtered by the collector 306. Consequently, the system 302 functions effectively by cleaning of the filter element 328 of the separator 304, whereas this is not required for the filter element 352 of the collector 306 as frequently. In this arrangement, dewatering may be assisted by forced drainage from the collector 306. Figure 18 is a schematic representation of an embodiment in which the particulates outlet 426 is also used as an inlet for a filtered fluid being returned from the collector 406 to the separator404. The embodiment has a return conduit 408 which is connected to the collector inlet conduit 456 and a valve 471 configured to regulate flow from the return conduit 408 to the inlet conduit 456. Figure 19 is a schematic representation of a further embodiment in which the particulates outlet 526 is also used as an inlet for a filtered fluid being returned from the collector 106 to the separator 104. The collector 106 comprises a baffle arrangement 576 configured to allow flow of mixture into the collector 106, and to trap particulates on return. Figure 20 is a schematic representation of an embodiment not having a float valve. In this arrangement the flow regulator comprises a valve 650 which can be operated to regulate flow into the collector 606. Figure 21 is a schematic representation of an embodiment having a regulator arrangement 750 in the form of a pump disposed between the particulates outlet of the separator 704 and the inlet of the collector 106 (i.e. the pump 750 is disposed in the flow path from the separator 104 to the collector 106). In this arrangement the pump 750 is operated to regulate flow of fluid through the particulates outlet 726 such that particulates are selectively flushed from the separator 704 through the particulates outlet 726 into the collector arrangement 706. Figure 22 is a schematic representation of an embodiment having a pump 856 disposed between the fluids outlet of the collector and the return inlet of the separator. In this arrangement, water that has been filtered by the collector 806 is returned to the separator 804 by the pump 856. This avoids the need fora gravity drain from the collector arrangement 806. It will be appreciated that various embodiments of the present disclosure have been described herein for purposes of explanation, and that various modifications may be made without departing from the scope of the claimed invention. Accordingly, the various embodiments described herein are not intended to be limiting, and that the invention is defined by the claims as supported by the description.

Claims

1. A system for separating particulates from a fluid, the system comprising:a separator configured to separate particulates from a fluid, the separator having a separator inlet, a fluids outlet through which fluid from which particulates have been separated is discharged from the separator, and a particulates outlet through which particulates separated from the fluid are discharged from the separator, anda regulator arrangement configured to regulate flow of fluid through the particulates outlet such that particulates are selectively flushed from the separator through the particulates outlet.

2. The system of claim 1, wherein the regulator arrangement has a first configuration in which flow of fluid through the particulates outlet is restricted and a second configuration in which particulates are flushed by a fluid through the particulates outlet.

3. The system of any one of the preceding claims, wherein the regulator arrangement is configured to regulate the flow of fluid from the separator through the particulates outlet independently of flow from the separator through the fluids outlet.

4. The system of any one of the preceding claims, wherein the regulator arrangement is configured to restrict flow of fluid from the separator through the particulates outlet based on a predetermined condition.

5. The system of claim 4, wherein the predetermined condition is that the pressure at the particulates outlet is not Less than a threshold pressure.

6. The system of claim 5, wherein the threshold pressure is the pressure at the separator inlet.

7. The system of claim 4, wherein the predetermined condition is that the volume of fluid through the particulates outlet over a set period is not Less than a predetermined volume.

8. The system of any one of the preceding claims, wherein the regulator arrangement is configured to selectively flush particulates from the separator through the particulates outlet by varying a pressure at the particulates outlet.

9. The system of any one of the preceding claims, wherein the regulator arrangement comprises a valve arrangement having a closed configuration in which flow of fluid through the particulates outlet is restricted and an open configuration in which particulates are flushed by a fluid through the particulates outlet.

10. The system of claim 9, wherein the valve arrangement is a pressure-activated valve arrangement that is configured to move into the closed configuration when a pressure at the particulates outlet exceeds a threshold pressure.

11. The system of claim 9 or 10, wherein the valve arrangement comprises a venting arrangement arranged to vent air from the collector, wherein the venting arrangement has an open configuration in which fluid can be vented from the collector through the venting arrangement and a closed configuration in which venting of fluid from the collector through the venting arrangement is prevented.

12. The system of claim 9 or 10, wherein the valve is disposed in the flow path from the separator to the collector.

13. The system of any one of the preceding claims, wherein the regulator arrangement comprises a pump arrangement configured to vary a pressure at the particulates outlet.

14. The system of claim 13, wherein the pump is disposed in the flow path from the separator to the collector.

15. The system of any one of the preceding claims, wherein the system further comprises a collector having a collector inlet arranged to receive particulates discharged from the separator through the particulates outlet.

16. The system of claim 15, wherein the collector comprises a collection chamber configured to receive particulates discharged from the separator through the particulates outlet.

17. The system of any one of the preceding claims, wherein the regulator arrangement is configured to restrict flow of fluid from the separator through the particulates outlet when the volume of a liquid within the collection chamber reaches a predetermined volume.

18. The system of any one of claims 13 to 15, wherein the collector has a collector fluids outlet and a filter element disposed between the collector inlet and the collector fluids outlet, the filter element is arranged to collect particulates greater than a predetermined size.

19. The system of any one of claims 15 to 18, wherein the collector inlet is in fluid communication with the particulates outlet via a conduit, the conduit is configured to inhibit flow from the collection chamber to the separator via the conduit during operation.

20. The system of anyone of claims 15 to 19, wherein the particulates outlet is in open fluid communication with the collector inlet.

21. The system of any one of the preceding claims, wherein the separator comprises a filter element disposed between the separator inlet and the separator fluids outlet and configured to separate particulates from a fluid which are greater than a predetermined size.

22. The system of claim 20, wherein the filter element is arranged such that fluid which is selectively flushed from the separator through the particulates outlet bypasses the filter element.

23. The system of claim 21 or 22, the separator comprising a separator chamber and the filter element divides the separator chamber into an unfiltered region and a filtered region, wherein the separator inlet is arranged to supply fluid to the unfiltered region, the fluids outlet is arranged to discharge fluid from the filtered region and the particulates outlet is arranged to discharge fluid and particulates from the unfiltered region.

24. The system of claim 23, wherein the separator chamber has an outer region and an inner region, the separator inlet is arranged to open into the outer region, the fluids outlet is arranged to open from the inner region and the particulates outlet is arranged to discharge fluid from the outer region, wherein the filter element is disposed between the outer region and the inner region of the separator chamber.

25. The system of any one of the preceding claims, wherein the system is configured such that, in use, a fluid mixture containing particulates supplied through the separator inlet into the separator is discharged through the particulates outlet in order to flush particulates from the separator through the particulates outlet.

26. The system of any one of the preceding claims, wherein the system comprises a pump arranged to pump a fluid through the separator inlet into the separator.

27. The system of claim 26, wherein the pump is disposed upstream of the separator inlet.

28. A method of separating particulates from a fluid using a system in accordance with any one of the preceding claims, the method comprising the steps:supplying a mixture comprising a fluid and particulates to the separator inlet;discharging a fluid from which particulates have been separated through the fluids outlet;regulating the flow of fluid through the particulates outlet using the regulator arrangement in order to selectively flush particulates from the separator through the particulates outlet.

29. The method of claim 28, wherein the step of regulating the flow of fluid through the particulates outlet comprises regulating a pressure at the particulates outlet.

30. The method of claim 28 or 29, wherein a fluid supplied via a separator inlet is used to flush particulates through the particulates outlet.

31. A system for separating particulates from a fluid, the system comprising:a first separator configured to separate particulates from a fluid, the first separator having a first separator inlet, a first separator fluid outlet through which fluid from which particulates have been separated is discharged from the separator, and a particulates outlet arranged to provide an outlet through which particulates separated from the fluid are discharged from the first separator; anda second separator configured to separate particulates from a fluid, the second separator having a second separator inlet arranged to receive particulates discharged through the particulates outlet of the first separator, a second separator fluid outlet through which fluid from which particulates have been separated is discharged from theseparator, the second separator fluid outlet is arranged in fluid communication with the first separator such that fluid discharged through the second separator fluid outlet is returned to the first separator.

32. The system of claim 31, the first separator is configured to separate particulates from the fluid which are greater than a first predetermined size and the second separator is configured to separate particulates from the fluid which are greater than a second predetermined size, wherein first predetermined size is smaller than the second predetermined size.

33. The system of claim 31 or 32, wherein the second separator is configured to collect particulates separated by the second separator.

34. The system of any one of claims 31 to 33, wherein the second separator is arranged with respect to the first separator such that a liquid within the second separator drains under gravity to the first separator via the second separator fluid outlet.

35. The system of any one of claims 31 to 34, wherein a valve is disposed between the second separator and the first separator to control the discharge of fluid from the second separator to the first separator through the second separator fluid outlet.

36. The system of claim 35, wherein the valve is a one-way valve arranged to prevent flow from the first separator to the second separator through the second separator outlet.

37. The system of any one of claims 31 to 36, wherein the second separator comprises a venting arrangement arranged to vent air from the second separator, wherein the venting arrangement has an open configuration in which fluid can be vented from the second separator through the venting arrangement and a closed configuration in which venting of fluid from the second separator through the venting arrangement is prevented.

38. The system of any one of claims 31 to 37, the separator comprising a separator chamber and a filter element which divides the separator chamber into an unfiltered region and a filtered region, wherein the separator inlet is arranged to supply fluid to the unfiltered region, the fluids outlet is arranged to discharge fluid from the filtered region and theparticulates outlet is arranged to discharge fluid and particulates from the unfiltered region.

39. The system of any one of claims 31 to 38, wherein the second separator fluid outlet is arranged in fluid communication with the first separator such that fluid returned to the unfiltered region of the first separator.

40. The system of any one of claims 31 to 39, wherein the second separator comprises a collecting chamber and a filter element which divides the collecting chamber into an unfiltered region and a filtered region, wherein the second separator inlet is arranged to supply fluid to the unfiltered region and the second separator fluids outlet is arranged to discharge fluid from the filtered region.

41. A system for separating solid particulates from a fluid, the system comprising:a separator configured to separate solid particulates from a fluid, the separator having a separator inlet, a fluids outlet through which fluid from which particulates have been separated is discharged from the separator, and a particulates outlet through which particulates separated from the fluid are discharged from the separator; anda collector having a collector inlet arranged to receive particulates discharged from the separator through the particulates outlet, wherein the system is configured to selectively discharge solid particulates from the separator through the solids outlet to the collector.

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