阅读说明：本技术 用于废水处理装置的托盘单元和用于废水处理装置的托盘组件的组装方法 (Tray unit for wastewater treatment apparatus and method of assembling tray assembly for wastewater treatment apparatus ) 是由 安东尼·塔德克·莱斯利·科兰科 约瑟夫·M·库利 于 2018-08-22 设计创作，主要内容包括：描述了一种用于废水处理装置的托盘单元。托盘单元具有大体上截头圆锥形轮廓,该截头圆锥形轮廓限定了轴线和中心孔。托盘单元包括围绕轴线布置的多个不同的托盘部分。每个托盘部分包括托盘单元的大体上截头圆锥形轮廓的一部分,并且可连接至一个或多个其他托盘部分,以形成托盘单元。还描述了一种用于废水处理装置的托盘组件的组装方法。该方法包括以下步骤：提供多个托盘单元,每个托盘单元具有大体上截头圆锥形轮廓和中心孔,并且包括多个连接凸耳,每个连接凸耳限定孔；通过将支撑构件穿过第一托盘单元的连接凸耳的孔插入并将第一托盘单元固定至支撑构件,将第一托盘单元附接至多个支撑构件；通过将支撑构件穿过第二托盘单元的连接凸耳的孔插入并将第二托盘单元固定至支撑构件以形成托盘单元的组件,将第二托盘单元附接至多个支撑构件。(A tray unit for a wastewater treatment plant is described. The tray unit has a generally frustoconical profile defining an axis and a central bore. The tray unit includes a plurality of different tray sections arranged about an axis. Each tray section comprises a portion of the generally frustoconical profile of the tray unit and is connectable to one or more other tray sections to form the tray unit. A method of assembling a tray assembly for a wastewater treatment plant is also described. The method comprises the following steps: providing a plurality of tray units, each tray unit having a generally frustoconical profile and a central bore and comprising a plurality of attachment lugs, each attachment lug defining a bore; attaching the first tray unit to the plurality of support members by inserting the support members through the holes of the connecting lugs of the first tray unit and fixing the first tray unit to the support members; the second tray unit is attached to the plurality of support members by inserting the support members through the holes of the connecting lugs of the second tray unit and securing the second tray unit to the support members to form an assembly of tray units.)

1. A tray unit for a wastewater treatment plant, the tray unit having a generally frusto-conical profile defining an axis and a central bore, the tray unit comprising a plurality of different tray sections arranged about the axis, each tray section comprising a portion of the generally frusto-conical profile of the tray unit and being connectable to one or more other tray sections to form the tray unit.

2. The tray unit of claim 1, wherein each tray section comprises a first edge region connectable to a second edge region of an adjacent tray section and a second edge region connectable to a first edge region of an adjacent tray section.

3. The tray unit of any one of the preceding claims, wherein a first edge region comprises at least one hole for connecting the first edge region to a second edge region of an adjacent tray section, and a second edge region comprises at least one corresponding slot for connecting the second edge region to the first edge region of an adjacent tray section.

4. The tray unit of claim 3, wherein the at least one slot is oriented in a circumferential direction relative to the axis.

5. The tray unit of any of claims 2 to 4, wherein each tray portion comprises a flange, wherein the flange defines the first edge region or the second edge region.

6. The tray unit of claim 5, wherein the flange is offset in an outward direction from a central portion of the tray unit.

7. A tray unit according to any one of the preceding claims, wherein at least one tray portion comprises at least one connecting lug, wherein the or each connecting lug defines a through-hole for receiving a support member.

8. The tray unit of claim 7, wherein the connecting lugs are integrally formed with the remainder of the tray portion.

9. A tray unit according to claim 7 or 8, wherein the connecting lugs comprise hollow channels extending between inlet and outlet ports formed in the outer edge of the tray portion.

10. The tray unit of any one of the preceding claims, wherein the tray portions are substantially identical.

11. A tray unit for a wastewater treatment plant, the tray unit having a generally frusto-conical profile defining an axis and a central aperture, the tray unit comprising at least one attachment lug defining an aperture for receiving a support member, the at least one attachment lug being integrally formed with the remainder of the tray unit.

12. The tray unit of claim 11, wherein the connecting lugs comprise hollow channels extending between an inlet and an outlet formed in an outer edge of the tray unit.

13. A tray unit as claimed in any one of the preceding claims wherein the frusto-conical profile of the tray unit is formed from a plurality of sections separated by steps to increase the rigidity of the tray unit.

14. The tray unit of any one of the preceding claims wherein the tray unit has a single wall thickness.

15. A tray unit as claimed in any one of the preceding claims, wherein one or more tray units are rotationally moulded.

16. A tray assembly for a wastewater treatment plant, the tray assembly comprising a plurality of tray units according to any one of the preceding claims and one or more support members, wherein each of the plurality of tray units is secured to at least one of the one or more tray units such that the tray units are spaced apart from each other along the axis.

17. A wastewater treatment plant comprising a tray unit or tray assembly according to any preceding claim.

18. A method of assembling a tray assembly for a wastewater treatment plant, the method comprising the steps of:

providing a plurality of tray units, each tray unit having a generally frustoconical profile and a central bore and comprising a plurality of attachment lugs, each attachment lug defining a bore;

attaching the first tray unit to the plurality of support members by inserting the support members through the holes of the connecting lugs of the first tray unit and securing the first tray unit to the support members; and

the second tray unit is attached to the plurality of support members by inserting the support members through the holes of the connecting lugs of the second tray unit and securing the second tray unit to the support members to form an assembly of tray units.

19. The method of claim 18, wherein each tray unit is supported by a clamp before and during attachment to the support member, wherein after attachment to the support member, a first tray unit is removable from the clamp and replaceable on the clamp by a second tray unit by lifting the assembly.

20. The method of claim 19, wherein the jig comprises a plurality of individual jig frames.

21. The method of any one of claims 18 to 20, further comprising assembling a plurality of individual tray sections to form each tray unit.

22. A method according to claim 21 when dependent on claim 20, wherein each tray section is supported by each jig frame.

23. The method of claim 22, wherein a jig frame is used to support and manipulate the tray sections during assembly of each tray unit.

24. The method of any one of claims 18 to 23, wherein a support member extends from the ring.

Technical Field

The present invention relates to a tray unit for a wastewater treatment apparatus and a method of assembling a tray assembly for a wastewater treatment apparatus.

Background

Wastewater treatment plants are known in which a plurality of trays are provided to remove grit from the wastewater stream. The grit particles entrained in the waste water stream settle on the inclined inner surface of each tray and subsequently these particles are drawn by gravity towards and through the openings in the trays into the collection zone. The grit-removed wastewater is passed through a tray for further treatment.

Such trays are costly to manufacture and difficult to transport. Furthermore, the trays must meet specific requirements regarding shape and dimensions to ensure optimal flow conditions within the wastewater treatment plant. Accordingly, it is desirable to provide a tray unit for a wastewater treatment device and a method of assembling a tray assembly for a wastewater treatment device that overcome these problems.

Disclosure of Invention

According to a first aspect of the present invention, there is provided a tray unit for a wastewater treatment plant. The tray unit has a generally frustoconical profile defining an axis and a central bore. The tray unit includes a plurality of different tray sections arranged about an axis. Each tray section comprises a portion of the generally frustoconical profile of the tray unit and is connectable to one or more other tray sections to form the tray unit.

Each tray portion may include a first edge region and a second edge region. The first edge region may be connected to a second edge region of an adjacent tray section. The second edge region may be connected to the first edge region of an adjacent tray section.

The first edge region may comprise at least one aperture for connecting the first edge region to a second edge region of an adjacent tray section. The second edge region may comprise at least one respective slot for connecting the second edge region to the first edge region of an adjacent tray section.

The at least one hole may be a circular hole.

The at least one hole may be a blind hole.

The at least one slot may be oriented in a circumferential direction relative to the axis.

Each tray portion may include a flange. The flange may define the first edge region or the second edge region.

The flange may be offset in an outward direction from a central portion of the tray unit.

The at least one tray portion may comprise at least one attachment lug. The or each attachment lug may define a through-hole for receiving the support member.

The connecting lugs may be integrally formed with the remainder of the tray portion.

The connecting lug may include a hollow passage extending between the inlet and the outlet. The inlet and outlet may be formed in an outer edge of the tray portion.

The tray portions may be substantially identical.

According to a second aspect of the present invention, there is provided a tray unit for a wastewater treatment plant. The tray unit has a generally frustoconical profile defining an axis and a central bore. The tray unit includes at least one attachment lug defining an aperture for receiving the support member. The at least one connecting lug is integrally formed with the remainder of the tray unit.

The connecting lug may include a hollow passage extending between the inlet and the outlet. The inlet and outlet may be formed in an outer edge of the tray unit.

The frusto-conical profile of the tray unit may be formed from a plurality of sections separated by steps to increase the rigidity of the tray unit.

The tray unit may have a single wall thickness.

The tray unit or tray portion may be rotationally molded.

The tray assembly may include a plurality of tray units. The tray assembly may include one or more support members. Each of the plurality of tray units may be secured to at least one of the one or more tray units such that the tray units are spaced apart from each other along the axis.

A wastewater treatment plant may be provided comprising a tray unit or tray assembly as described above.

According to a third aspect of the present invention, there is provided a method of assembling a tray assembly for a wastewater treatment plant, the method comprising the steps of: a plurality of tray units are provided, each having a generally frustoconical profile and a central aperture, and including a plurality of attachment lugs, each attachment lug defining an aperture. The first tray unit is attached to the plurality of support members by inserting the support members through the holes of the connecting lugs of the first tray unit and securing the first tray unit to the support members. The second tray unit is attached to the plurality of support members by inserting the support members through the holes of the connecting lugs of the second tray unit and securing the second tray unit to the support members to form an assembly of tray units.

Each tray unit may be supported by a clamp before and during attachment to the support member. After attachment to the support member, the first tray unit may be removed from the jig and replaced on the jig by the second tray unit by lifting the assembly.

The jig may comprise a plurality of individual jig frames.

The method may further comprise assembling a plurality of individual tray sections to form each tray unit.

Each tray section may be supported by each clamp frame.

The jig frame may be used to support and manipulate the tray sections during assembly of each tray unit.

The support member may extend from the ring.

Drawings

For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:

fig. 1 is a perspective cross-sectional view of a separator according to an embodiment of the invention.

Fig. 2 is a cross-sectional view of the separator.

Fig. 3 is a sectional view of the separator taken in a direction perpendicular to fig. 2.

Fig. 4 is a top view of the tray unit of the separator in a fully assembled state.

Fig. 5 is a perspective view of a part of the tray unit.

Fig. 6 is a close-up perspective view of the tray portion.

FIG. 7 is a close-up perspective view of two adjacent tray sections separated from each other.

Fig. 8 shows two adjacent trays in a connected state.

Fig. 9 is a close-up perspective view of the attachment lugs of the tray portion.

FIG. 10 is a cross-sectional view of an attachment lug.

Fig. 11 is a perspective view of a jig for assembling the tray assembly.

Fig. 12 is a perspective view of a clamp frame of the clamp.

Fig. 13 shows a jig used during the first step of the assembly process.

Fig. 14 shows a second step of the assembly process.

Fig. 15 shows a third step of the assembly process.

Fig. 16 shows a fourth step of the assembly process.

Fig. 17 shows a fifth step of the assembly process.

Detailed Description

Fig. 1 shows a separator 2, the separator 2 comprising a tray assembly 4 disposed within a process vessel 6. The tray assembly 4 comprises a plurality of nested tray units 14. Five tray units 14 are shown in fig. 1, but it should be understood that the tray assembly may include more or fewer tray units 14. The nested tray units 14 define a separator axis 16, as shown in fig. 2 and 3, which is upright and preferably substantially vertical. The tray units 14 are spaced apart from one another along an axis 16. The processing vessel 6 is provided with an inlet chute 8 and a fluid outlet 12.

Each tray unit 14 comprises a generally frusto-conical tray 18 having a circular aperture 20 at the apex of the tray 18. The axis of the conical shape of the tray 18 is aligned with the separator axis 16. The trays 18 are gathered in a downward direction. A cylindrical rim 24 extends upwardly from the outer periphery of the tray 18, and an annular lip 26 extends radially inwardly from the end of the rim 24. The radially inward portion of the annular lip 26 is inclined in a direction parallel to the upper surface of the tray 18. The rim 24 and annular lip 26 are formed integrally with the tray 18 by a folded portion of the tray. The support frame 106 connects the plurality of tray units 14 of the tray assembly 4 together and supports the tray assembly 4 within the processing container 6.

Referring to fig. 2 and 3, the entry chute 8 has a single entry port 30 and a plurality of exit ports 32. The chute 8 extends into the processing receptacle 6 through the outer wall of the processing receptacle 6 and is in direct communication with the tray assembly 4. The middle of the chute 8 slopes in a downward direction from the inlet 30 to the outlet 32. The middle of the chute 8 diverges from the inlet 30 to the outlet 32 in the vertical direction. The outlet 32 is vertically aligned and extends horizontally from the lower end of the central portion of the chute. Each outlet 32 is in direct communication with a respective tray unit 14 and is arranged tangentially with respect to the separator axis 16. Specifically, the outlet 32 is in direct communication with the area between the annular lip 26 and the upper surface of the tray 18.

A plate 34 provided with a funnel portion 36 is arranged in the bottom of the processing container 6. The plate 34 extends horizontally within the confines of the container 6 and the funnel portions 36 converge in a downward direction. The gravel tank 10 is arranged in the lower region of the funnel part 36 and forms a sump at the bottom of the container 6 for collecting gravel. The funnel portion 36 is arranged coaxially with the separator axis 16.

Fig. 4 shows a top view of one of the tray units 14. The tray unit 14 is formed of a plurality of tray sections 38. In this example, the tray unit 14 includes four tray sections 38. Each tray portion 38 has a single wall thickness, and each tray portion 38 is identical or substantially identical. The tray portion 38 is a separate (i.e., distinct/independent) component. However, when connected together they form a single tray unit 14.

Fig. 5 shows a separate one of the tray sections 38. The tray portion 38 generally includes a tray portion 18', a rim portion 24 ', and a lip portion 26 '. The tray portion 18' is in the shape of a generally frusto-conical sector. The tray portions 18' converge in a downward direction toward the arcuate edge 40. The tray portion 18' includes a lower portion 44, an intermediate portion 46 and an upper portion 48, which are spaced apart by a series of arcuate steps 42 (not shown in fig. 1-3 and 13-17 for clarity). Each arcuate step 42 includes a vertical surface that faces (i.e., points towards) the arcuate edge 40. In total, two arcuate steps 42 are shown that divide the tray portion 18' into a lower portion 44, an intermediate portion 46, and an upper portion 48. Each of the lower portion 44, the intermediate portion 46 and the upper portion 48 is in the shape of a frusto-conical sector. The frusto-conical sectors forming the lower portion 44, the middle portion 46 and the upper portion 48 are substantially parallel. Each arcuate step forms a portion of a cylindrical surface. Each arcuate step is concentric. The edge portion 24' forms a part of the cylindrical surface. The rim portion 24 'extends upwardly from the periphery of the tray portion 18'. A pair of lugs (i.e., tabs) 58 project outwardly from the rim portion 24'. The lip portion 26 'extends radially inward from the end of the rim portion 24' and terminates in an arcuate edge 41. The radially inward portion of the lip portion 26 'is inclined to be parallel to the direction of the upper surface of the tray portion 18'.

The first edge 50 of the tray portion 38 extends between one end of the arcuate edge 40 of the tray portion 18 'and a corresponding end of the arcuate edge 41 of the lip portion 26'. A plurality of metal fasteners 53 are integrated into the tray portion 38 adjacent the first edge 50. In the arrangement shown in fig. 5, two fasteners 53 are provided in each of the lower, middle and upper portions 44, 46, 48. A single fastener 53 is provided in the edge portion 24 'and a single fastener 53 is provided in the lip portion 26'. As shown more clearly in fig. 7, each fastener 53 includes a threaded bore 54 for receiving a screw. The threaded hole 54 is a blind hole and extends from the opening into the boss 57. The threaded hole 54 is a circular hole. The fasteners 53 are integrated into the body of the tray portion 38 such that the openings of the threaded holes 54 are on the outer surface of the second tray portion 38 and the bosses 57 are on the inner surface of the second tray portion 38.

A second edge 52 of the tray portion 38 extends between the other end of the arcuate edge 40 of the tray portion 18 'and the corresponding other end of the arcuate edge 41 of the lip portion 26'. As shown more clearly in fig. 6, a flange 55 extends along the second edge 52. A plurality of slots 56 extend through the flange 55 adjacent the second edge 50. The number and location of the plurality of slots 56 extending through the tray portion 38 adjacent the second edge 52 corresponds to the number and location of the fasteners 53 integrated into the tray portion 38 adjacent the first edge 50. The slot 56 is oriented in the circumferential direction (i.e., has its largest dimension).

Fig. 7 shows two adjacent tray sections 38 prior to assembly. As shown, a first edge 50 of one tray section is adjacent to an opposing second edge 52 of an adjacent tray section. The flange 55 extends in the circumferential direction. As shown, the flange 55 is offset in an outward direction from the remainder of the tray portion 38. In addition, the inner surface of the flange 55 is offset in an outward direction from the inner surface of the remainder of the tray portion 38. The portion of the flange 55 formed by the lower 44, middle 46 and upper 48 portions, the arcuate step 42, the cylindrical edge 24 'and the annular lip 26' is contoured substantially parallel to the corresponding portion of the remainder of the tray portion 38. The extent to which the flange 55 is offset in an outward direction from the remainder of the tray portion 38 is such that the contour of the inner surface of the flange 55 of the tray portion 38 (i.e., the upper surface of the flange 55 is at the outer surface). The extent to which the flange 55 is offset in an outward direction from the remainder of the tray portion 38 is such that the profile of the inner surface of the flange 55 of the tray portion 38 (i.e., the upper surface of the flange 55 at the tray portion 18', the radially inward surface of the flange 55 at the rim portion 24', and the downward facing portion of the flange 55 at the lip portion 26 ') corresponds to the profile of the outer surface of the adjacent tray portion 38 (and its own outer surface) along the first edge 50 (i.e., the lower surface of the tray portion 18' is adjacent the first edge 50, the radially outward surface of the rim portion 24 'is adjacent the first edge 50, and the upward surface of the lip portion 26' is adjacent the first edge 50). Thus, as shown in fig. 8, the first edge 50 of one second tray section 38 can be inserted into the flange 55 of an adjacent tray section 38.

The tray portion 18', the rim portion 24 ' and the lip portion 26' are integrally formed with one another. The body of the tray portion 38 is formed of plastic and is manufactured by a rotational molding (i.e., rotational molding or rotational molding) process. The metal fasteners 53 are provided as inserts in the body of the tray portion 38 during the rotational molding process.

When the tray portions 38 are assembled together, the tray portion 18' forms the tray 18, the edge portion 24 ' forms the cylindrical edge 14, and the lip portion 26' forms the annular lip 26. Further, when assembled, the arcuate edge 40 defines the aperture 20. In this way, each tray portion 38 forms a sector (in this case a quarter circle) of the tray unit 14.

Referring now to fig. 9, fig. 9 shows a close-up view of one of lugs 58, and fig. 10 shows a cross-section of lug 58. The lug 58 is hollow and includes an outwardly extending portion 62, a circumferentially extending portion 64, and an inwardly extending portion 66. The outwardly extending portion 62 extends outwardly away from the edge portion 24' intersecting with a circumferentially extending portion 64. The circumferentially extending portion 64 extends circumferentially (i.e., about an axis) between the outwardly extending portion 62 and the inwardly extending portion 66. An inwardly extending portion 66 extends inwardly from the circumferentially extending portion 64 and extends toward the rim portion 24'. Thus, the lugs 58 are generally C-shaped. An inlet 70 is formed where the outwardly extending portion 62 meets the rim portion 24 ', and an outlet 72 is formed where the inwardly extending portion 66 meets the rim portion 24'. The lugs 58 are integrally formed with the remainder of the tray portion 38.

The outwardly extending portion 62, circumferentially extending portion 64, and inwardly extending portion 66 are defined by an upper surface 74, a lower surface 76, a radially outer surface 78, and a radially inner surface 80. The lower surface 76 forms a continuation of the tray portion 18' and is therefore inclined. The upper surface 74 extends generally horizontally and is offset downwardly from the lip portion 26'.

The radially inner surface 80 and the opposing portion of the rim portion 24' together define a vertical through-hole 82. A vertical through bore 82 extends between the upper surface 78 and the lower surface 76 of the lug 58. As shown in fig. 10, the vertical through-hole 82 is a slot (i.e., an elongated opening). The vertical through-holes 82 are oriented in the circumferential direction (i.e., have their largest dimension). In an alternative arrangement, the vertical through hole 82 need not be a slot (i.e., it need not be an elongated opening). A horizontal slot 84 also extends through the circumferentially extending portion 64 between the outer surface 78 and the inner surface 80. The horizontal slot 84 is also oriented circumferentially (i.e., has its largest dimension). In an alternative arrangement, the horizontal slot 84 may be a horizontal hole that is not a slot (i.e., it need not be an elongated opening). The horizontal slot 84 is formed by a closed passage (i.e., tunnel) extending through the circumferentially extending portion 64. Thus, the ledge 58 defines a completely closed channel.

The channel has a substantially rectangular vertical cross-section along its length. Since the vertical through holes 82 and the horizontal slots 84 are elongated and have the largest dimension in the circumferential direction, the vertical through holes 82 and the horizontal slots 84 have the least effect on the ability of the fluid to pass along the passage. The lugs 54 are generally elongate and have a maximum dimension in the circumferential direction which further facilitates the passage of fluid along the channel. The outer vertical surfaces 78 of the outwardly extending portion 62 and the inwardly extending portion 66 are angled with respect to each other. The inner vertical surfaces 80 of the outwardly extending portion 62 and the inwardly extending portion 66 are parallel to each other and extend perpendicular to the edge portion 24'. Further, as previously described, the lower surface 76 is inclined, while the upper surface 74 is horizontal. Thus, the outwardly extending portion 62 and the inwardly extending portion 66 taper (i.e., decrease) from the inlet 70 and the outlet 72, respectively.

The corner edges formed between inner surface 80 and edge portion 24' are rounded, as are the corner edges of inner surface 80 formed at the transitions between outwardly extending portion 62, inwardly extending portion 66, and circumferentially extending portion 62.

Fig. 11 shows a fixture 86 for assembling a plurality of assembled tray units 14 together. The clamp 86 includes a plurality of clamp frames 88 arranged about the axis 3. The jig frames 88 are spaced apart from each other by an equal distance. A total of four clamp frames 88 are shown in fig. 10. Each clamp frame 88 is substantially identical.

Fig. 12 shows a clamp frame 88. The jig frame 88 includes a pair of support members 90, the pair of support members 90 extending in a downward direction toward the axis 3. An upwardly extending lip 92 projects from each support member 90 at a radially inner end thereof. The support member 90 is supported at its radially inner end by a first vertical rod 94 and at its radially outer end by a second vertical rod 96. The first and second pairs of vertical bars 94, 96 are supported by a base 98. The base 98 includes an inner base member 100 extending between the lower ends of the first vertical support members 94, an outer base member 102 extending between the lower ends of the second vertical support members 96, and a pair of radial base members 104 each extending radially between the lower end of one of the first vertical rods 94 and the lower end of a corresponding one of the second vertical rods 94.

As shown in fig. 13, to form the tray assembly 4 from a plurality of tray sections 38, a single tray section 38 is placed on each jig frame 88. The support member 90 supports the lower surface of the tray portion 18'. The upwardly extending lip 92 supports the arcuate edge 40 of the tray portion 38. The clamp 86 provides shape and structure to an otherwise relatively unstable set of components prior to securing the tray portion 38 and the tray unit 14 together. In addition, the clamps 86 position the tray sections 38 in the correct relative positions prior to securing the tray sections 38 together.

As shown in fig. 8, the tray sections 38 are assembled such that the inner surface of the flange 55 of each first tray section 38 abuts the outer surface of the adjacent tray section 38 adjacent its first edge 50. The slots 56 of each tray section 38 are aligned with the threaded holes 54 of the adjacent tray section 38 and are secured to each other by passing a screw or bolt (not shown) through each slot 56 and threading them into the threaded holes 54 of the fasteners 53. The circumferentially oriented slots 56 allow the spacing between the tray portions 38 to vary slightly to allow for manufacturing tolerances. Because threaded holes 54 are blind holes, fluid, grit, and debris cannot pass from the upper surface of tray 18 to the lower surface of tray 18 through threaded holes 54. The circumferentially oriented slots 56 allow the spacing between the tray portions 38 to vary slightly to allow for manufacturing tolerances. Because threaded holes 54 are blind holes, fluids, grit, and debris cannot pass from the upper surface of tray 18 to the lower surface of tray 18 through threaded holes 54.

Once all of the tray sections 38 are connected together in this manner, the support frame 106 is positioned over the tray unit 14 and the clamps 86, as shown in fig. 14. The support frame 106 includes a ring 108 with a plurality of connecting members 110 (or legs) extending axially from the ring 108. A total of eight connecting members 110 are shown in fig. 14, corresponding to the number of lugs 58 of the tray portion 38. The distance between the connecting members 110 is equal to the distance between the vertical through holes 82 formed in the lugs 58. The distance between the lugs 58 of a single tray section 38 may be the same as the distance between adjacent lugs 58 of adjacent tray sections 38, such that the legs are all equally spaced around the ring 108. The radius of the ring 108 is substantially equal to the desired distance between the center of the tray unit 14 and the vertical through hole 82. Each attachment member 110 has a plurality of radially extending threaded holes 112 (i.e., securing holes 112) spaced along its length for attaching the tray unit 14 to the attachment member 110.

As shown in fig. 14, the support frame 106 is aligned with the first tray unit 14 such that the connection member 110 is aligned with the through hole 82 of the first tray unit 14. The connecting member 110 is then inserted through the through hole 82 until the ring 108 is adjacent the annular lip 26 of the first tray unit 14. The resulting arrangement is shown in fig. 15. The first tray unit 14 is then independently fixedly secured to the support frame 106 (and in particular the connecting members 110 thereof) by inserting screws or bolts (not shown) through the slots 84 into the corresponding securing holes 112 of the connecting members 110.

Once the support frame 106 is secured to the first tray unit 14, the tray unit 14 can be raised such that the first tray unit 14 is lifted off the clamp 86. The second tray unit 14 is then placed on the jig 86 in a similar manner as previously described. The resulting arrangement is shown in fig. 16.

The same process as described above is then repeated to assemble the second tray unit 14 from the plurality of tray parts 38 and attach the second tray unit 14 to the connecting member 110. The second tray units 14 are attached to the connecting members 110 such that the tray units 14 are axially spaced from each other. The spacing of the tray units 14 is determined by the spacing of the fixing holes 112 along the connecting members 110. The same process is then repeated for the third tray unit 14 (and any subsequent units) to form the completed tray assembly 4.

Each tray unit 14 is independently fixedly secured to the connecting member 110 of the support frame 106. The tray units 14 are fixedly secured to the connecting members 110, i.e., substantially immovable relative to the connecting members 110, such as by sliding along the connecting members 110, when they are secured to the connecting members 110. The tray units 14 are independently fixedly secured to the connecting members 110 because none of the tray units 14 require the presence of the other tray units 14 to be secured to the connecting members 110.

As shown in fig. 17, the tray assembly 4 may then be lifted from the fixture 86, as shown in fig. 1-3, and installed into a processing vessel. If the connecting member 110 is sufficiently long, additional tray units 14 may be secured to the support frame 106.

In use, sand settles on the upper surface of the trays 18 of the tray unit 14, migrating along the upper surface under the influence of gravity and passing through the apertures 20. Since the tray unit 14 includes the plurality of tray portions 38, rather than being formed of a single member, the structural rigidity of the tray unit 14 is improved. The structural rigidity of the tray unit 14 is also improved by the steps 42 formed around the tray 18. Furthermore, because the tray 18 slopes downwardly toward the hole 20, the steps 42 do not interfere with the migration of sand toward the hole 20.

In use, a low energy vortex is established between adjacent tray units 14. A portion of the interior of the tray 18 adjacent the edge 24 is able to flow through the channel formed by the ledge 58. Specifically, flow enters the lug via inlet 70, flows along outwardly extending portion 62, along circumferentially extending portion 64, along inwardly extending portion 66, and exits lug 58 via outlet 72. The arrangement of lugs 58 does not protrude into the interior of the tray unit 14, thereby minimising the effect of the lugs 58 on the vortex flow and its effect on the tray settling pattern. Furthermore, such an arrangement prevents debris from collecting within the bin. By flowing the wastewater in this manner, the effect of the lugs 58 on the vortex is minimized. Furthermore, because the lugs 58 are integrally formed with the remainder of the tray portion 38, a separate step of attaching the lugs 58 to the remainder of the tray portion 38 is not required.

As previously described, the body of the tray portion 38 is rotationally molded. Rotomolded articles are known to experience large shrinkage during cooling. By forming the tray unit 14 from a plurality of tray sections 38 rather than a single component, the effects of shrinkage are reduced, particularly for large components. This results in an accurate, repeatable, efficient and fast manufacturing process, resulting in an improved quality of the tray unit 14.

Although it has been described that each tray unit 14 includes four tray sections 38, each tray unit 14 may include any number of tray sections 38. The size of the tray unit 14 can be increased by increasing the number of tray sections 38 used to form each tray unit 14. Conversely, large tray units 14 that would be difficult or impossible to transport can be transported as individual tray sections 38, thereby reducing transportation costs and difficulty.

It has been described that each tray portion 38 has a single wall thickness. However, the tray portion 38 may alternatively have twice the wall thickness. The double wall thickness may increase the strength and rigidity of the tray portion 38. For additional or alternative steps 42, a double wall thickness may be used. Also, ribs may be provided in addition to or instead of the steps 42 or double the wall thickness. Ribs may be provided on the underside of the tray 18 to avoid interfering with the migration of sand to the holes 20. For example, the ribs may be circular in shape, depending on the step 42.

While certain features, such as lugs 58, have been described in the context of a tray unit 14 that includes multiple tray portions 38, they may also be implemented in a unitary tray unit 14, where possible.

Alternative manufacturing processes other than rotational molding may be used to manufacture tray portion 38 or tray unit 14. The tray portion 38 or tray unit 14 may be manufactured using vacuum forming, thermoforming, or any other suitable manufacturing process.

Although the tray unit 14 has been described for use in stacked tray separators, the tray unit 14 may alternatively be used in other wastewater separators, such as hydrodynamic vortex separators.

It has been described that the tray portions 38 are connected together and to the connecting member 110 by threaded fasteners and holes. However, any type of connection or fastening means may be used.

It has been described that each tray portion 38 is identical or substantially identical. However, alternative arrangements may include a first type of tray portion 38 and a second type of tray portion 38. The first type of tray portion 38 can include a first flange 55 extending along the first edge 50 thereof and a second flange 55 extending along the second edge 52 thereof. Thus, the first and second edges 50, 52 of the first type of tray portion 38 may correspond to the second edges 52 of the arrangement described above. In contrast, the second type of tray portion 38 may not have any flanges 55. The first edge 50 and the second edge 52 of the second type of tray portion 38 may thus correspond to the first edge 50 of the arrangement described above. The tray portions 38 may be arranged in the above-described arrangement, but with alternating tray portions 38 of the first and second types.