HK1072738B - A solids separator - Google Patents

Description

Solid separator

Technical Field

The present invention relates to solids separators and, more particularly, to solids separators that separate particles entrained in a fluid stream.

Background

Separation of solids from wastewater remains a fundamental problem in wastewater treatment. There are essentially two physical methods available for removing solids from wastewater: filtering and precipitating.

The waste stream is typically filtered by passing it through a porous medium. The solid matter is captured due to the surface activity of the filter media or the size of the solid matter relative to the filter pores. Screening is a filtration method that relies solely on the relative sizes of the pores and the incoming solid matter. The main disadvantage of this filtration method is that the medium becomes fouled with time and must be cleaned. In order to achieve a high clearance of fine particles, a back flush with sophisticated process monitoring is required in order to ensure efficient filtration.

Sedimentation is a method of separating sewage solids by the small density difference of sewage solids and water using gravity. The low relative density of the solids and the fine size of the constituent materials means that settling must be done by means of very large stationary flow tanks or by means of indoor centrifugation to improve the gravity process. In general, centrifugation is not a continuous process, or is limited to very low processing rates.

Disclosure of Invention

It is an object of the present invention to provide an alternative unit operation for concentrating solids from a fluid stream in a continuous process.

According to one aspect of the present invention there is provided a solids separator comprising: an elongated tubular rotatable housing rotatable about a central axis; a fluid inlet at one end of said housing adapted to receive a fluid stream containing entrained solids; first and second outlets at opposite ends of the housing; wherein the rotating housing is effective to apply a radially outward force to entrained solids flowing through the separator to cause solids to be concentrated at the peripheral portion of the cross-section of the flow at the first and second outlets, and the first outlet is adapted to receive the interior of the cross-section of the flow and the second outlet is adapted to receive the peripheral portion of the cross-section of the flow containing concentrated solids.

The entry points of the first and second outlets are preferably in the form of tubular separators mounted longitudinally within the rotating housing so as to define a second outlet therebetween, the second outlet receiving a peripheral portion of the cross-section containing the concentrated stationary stream. The inner or filtrate flow of the cross-section of the flow passes through a tubular separator defining a first outlet.

The tubular separator is preferably rotated at the same rpm as the rotating shell. Alternatively, the tubular separator may be rotated faster or slower than the rotating housing.

According to another aspect of the present invention there is provided a solids separator comprising: a long tubular rotary housing rotatable about a central axis; a fluid inlet at one end of said housing adapted to receive a fluid stream comprising entrained solids; a plurality of outlets at opposite ends of said housing, wherein said rotating housing is effective to apply a radially outward force to entrained solids flowing through the separator such that denser solids are located in a peripheral portion of the cross-section of the flow and lighter solids are located near the central axis, said plurality of outlets being adapted to receive different portions of the cross-section of the flow.

Such a solids separator preferably includes a vortex inducing device attached to the rotating housing, wherein the vortex inducing device assists in applying a radially outward force to entrained solids.

The swirl inducing device is preferably formed by an impeller, preferably arranged in front of the rotating housing. The swirl inducing means preferably rotate at the same rpm as the rotating housing. Alternatively, the vortex inducing means may rotate faster or slower than the rotating housing.

The swirl inducing means is preferably arranged before the rotating housing so as to impart a radially outward force on the entrained particles before they enter the rotating housing.

The solids separator preferably includes an automated pumping device connected to the rotating housing, wherein the automated pumping device assists in drawing fluid through the solids separator.

The automatic pumping means is preferably constituted by an impeller, and is preferably arranged at the outlet of the rotating casing. More preferably, the automatic pumping device rotates at the same rpm as the rotating housing. Alternatively, the automatic pumping device may rotate faster or slower than the rotating housing.

The angular velocity of the fluid over the peripheral portion of the cross-section of the flow is substantially the same as the angular velocity of the rotating housing.

The rotating housing rotates at a rotational speed of between 500 and 5000 revolutions per minute. The rotating housing is more preferably rotated at a speed of between 600 and 3000 rpm, preferably between 800 and 1500 rpm.

The solids separator is preferably oriented in a substantially vertical arrangement, and more preferably the fluid inlet is provided at the bottom of the arrangement.

The flow rate of the fluid through the separator is preferably such that there is minimal turbulence within the separator, and more preferably the fluid flows in a substantially laminar manner.

The solids separator may include radially extending vanes mounted thereon, wherein the vanes assist in maintaining the angular velocity of the fluid and/or provide structural support to the solids separator. More preferably, the guide vanes are equally spaced circumferentially. Preferably, the plurality of vanes is repeated longitudinally along the fluid flow path.

The solids separator may also include a central shaft passing through the rotating housing, wherein the shaft prevents fluid from flowing through the separator on the central shaft and/or provides structural support to the solids separator. Swirl inducing means and/or automatic pumping means and/or radially extending guide vanes may be connected to the central shaft.

In another aspect of the invention, there is provided a solids separator comprising: an elongated tubular outer housing rotatable about a central axis; an elongated tubular inner housing mounted within said outer housing for rotation about said central axis to define a flow passage between said outer and inner housings; a fluid inlet at one end of the flow passage and adapted to receive a fluid stream containing entrained solids; first and second outlets at opposite ends of the flow passage; wherein the rotatable outer and inner housings are effective to apply a radially outward force to entrained solids flowing through the flow passage to cause solids to be concentrated at peripheral portions of the cross-section of the flow at the first and second outlets, the first outlet being adapted to receive an inner portion of the cross-section of the flow and the second outlet being adapted to receive a peripheral portion of the cross-section of the flow containing concentrated solids.

The outer housing preferably rotates at the same rpm as the inner housing.

Preferably, the first and second outlets are defined by a tubular separator mounted longitudinally between the outer and inner housings such that the second outlet is defined between the tubular separator and the outer housing and the first outlet is defined between the tubular separator and the inner housing. The tubular separator is preferably rotatable and may rotate at the same rpm as the outer or inner housing.

The solids separator preferably includes a swirl inducing device, wherein the swirl inducing device helps to impart a swirling outward force to the entrained solids. The swirl inducing means is preferably an impeller disposed on the outer surface of an inverted bell, the outermost circumference of which is connected to the peripheral edge of the inner housing adjacent the inlet of the flow passage. It also preferably acts as an automatic pumping device to push or lift the fluid into the flow passage.

The angular velocity of the fluid over the peripheral portion of the cross-section of the flow is preferably substantially the same as the angular velocity of the outer casing. The outer and inner housings preferably rotate at a speed of between 500 and 5000 rpm, more preferably between 600 and 3000 rpm, and most preferably between 800 and 1500 rpm.

The stationary separator preferably includes a central shaft passing through the inner rotating housing, wherein the shaft provides structural support to the solids separator. The central shaft may be connected to a motor or similar device and drive the inner and outer housings and the vortex inducing device. The solids separator preferably includes an outer housing enclosing an outer rotatable shell.

Typically, the fluid is a liquid such as waste liquid and the solids are particles in a waste stream, however, the separator may be used with any fluid stream that includes dense and/or buoyant particles.

The solids separator may be used in place of a clarifier or settling tank, or in place of or prior to any unit operation that is limited by the settling rate of solids. More preferably, the solids separator may be used to reduce the solids flux load of a clarifier operating in a biological wastewater treatment facility.

In another aspect, the solids separator described above can be used to collect a sample of the free phase (liquid/solid) of activated sludge of a biological treatment setting.

Drawings

The invention will be better understood from the detailed description of preferred but non-limiting embodiments, with reference to the attached drawings.

FIG. 1 shows a cross-sectional view of a solids separator according to the present invention;

FIG. 2 shows front and side views of a solids separator according to the invention;

FIG. 3 shows a cross-sectional view of a sampling device according to the present invention;

fig. 4 shows a front and a side view of the outside of a sampler according to the invention;

FIG. 5 shows a cross-sectional view of a solids separator according to the present invention;

FIG. 6 shows an inlet section of a solids separator according to the invention;

FIG. 7 shows an outlet section of a solids separator according to the invention;

FIG. 8 shows a cross-sectional view A-A of FIG. 7;

FIG. 9 shows a cross-sectional view B-B of FIG. 7;

FIG. 10 shows a swirl inducing device and an automatic pumping device of a solids separator according to the present invention; and

figure 11 shows the fluid entry point with swirl inducing means of the solids separator according to the invention.

Detailed Description

Referring now to figures 1 and 2, there is shown a solids separator 1 comprising a fluid inlet 2 and two fluid outlets 3, 4. The solids separator 1 also includes a swirl inducing portion 5 which imparts a radially outward force on any solids entrained in the fluid flowing through the separator before the fluid enters the rotating housing 6. The swirl inducing portion 5 comprises impellers 7, 8 mounted on a central shaft 9 extending on the central axis of the separator 1. The central shaft 9 is rotated by means of an electric motor or other suitable means, which also rotates the rotary housing 6 through a connection via supporting blades 10 on the central shaft 9.

The fluid entering the separator 1 is initially caused to rotate in a circular motion by the swirl inducing portion 5 before entering the rotating housing 6, and particles entrained in the fluid flow in the rotating housing 6 move towards the inner surface of the rotating housing 6. Since the shell 5 rotates at an angular velocity similar to that of the fluid, there is minimal turbulence as the fluid flows through the separator, and the fluid flows in a substantially laminar manner. The fluid flow is divided into an outer cross-sectional portion and an inner cross-sectional portion by means of a tubular separator 11 located inside the rotating casing 6. The inner cross-section is then directed to the filtrate outlet 3 and the outer cross-section containing the concentrated entrained particles is directed to the solids outlet 4.

Referring now to fig. 3 and 4, there is shown a sampling device 21 according to the present invention. The device 21 is typically placed in a fluid containing entrained solids and/or a mixture of fluids of different densities where a sample of a particular component having a specific gravity of the fluid is desired.

The device 21 includes a central shaft 22 located on the central axis of the device 21. The shaft is mounted to the rotating housing 23 by a guide vane 24 and also to a swirl inducing impeller 25. The shaft 22 is rotated by a motor or other suitable means 26, which in turn rotates the rotating housing and vortex inducing impeller.

The sample is collected by placing the device 21 in a fluid mixture, wherein the fluid is drawn into the device 21 at the inlet 27. As the fluid flows into the rotating housing 23, the fluid initially causes the impeller 25 to rotate in a circular motion by means of the vortex. Since there is virtually no turbulence and the fluid flows through it in a substantially laminar manner, the angular velocity of the fluid divides the cross-sectional flow of the fluid mixture into zones of different densities. The denser region is adjacent to the rotating housing 23 and the lighter region is adjacent to the central shaft 22. A pipette is then used at the outlet of the device to collect a sample from the area of desired fluid density, with the remainder of the fluid flowing through being directed to outlet 29.

Referring now to fig. 5 to 9, there is shown a solids separator generally designated 50 which includes a fluid inlet 51 and two fluid outlets 52 and 53. The separator also includes a swirl inducing device 54 which imparts a radially outward force on any solids entrained in the fluid flowing through the separator 50 before the fluid enters the flow path between the inner 55 and outer 56 rotating housings. The swirl inducing device 54 is provided on the outer surface of an inverted bell mounted on the periphery of the inner housing 57. The swirl inducing means is in the form of an impeller along the outer surface of the bell which is configured not only to apply a radially outward force to the fluid but also to have a lifting or self-pumping effect to move the fluid into the flow passage 58. A central shaft 60 rotates the vortex inducing device and the inner and outer housings 55 and 56. The central shaft 60 is typically rotated by a motor or other suitable means.

Fluid entering separator 50 begins to rotate and rise into flow passage 58 by swirl inducing device 54. Upon entering flow passage 58, inner rotating housing 55 and outer rotating housing 56 maintain the angular velocity of the fluid, and thus the particles entrained within the fluid move toward the inner surface of outer rotating housing 56 or the peripheral portion of the cross-section of flow passage 58. Since the inner and outer casings 55, 56 rotate at a similar rate to the angular velocity of the fluid, there is minimal turbulence as the fluid flows through the separator 50, and the fluid flows in a substantially laminar manner. The fluid streams are separated at outlets 52 and 53. Thus, the tubular separator 59, mounted longitudinally between the inner and outer housings 55, 56, defines the second outlet 52 between the tubular separator 59 and the outer housing 56, and the first outlet 53 between the tubular separator 59 and the inner housing 55. When the fluid reaches the first and second outlets 52 and 53, the entrained anchors have moved to the peripheral part of the cross-section of the flow, thus moving out of the separator via the second outlet 52. The remainder of the fluid or filtrate exits the separator via the first outlet 53. The tubular separator may also be rotated by means of a central shaft 60.

Referring now to fig. 8, therein is shown a cross-section a-a of fig. 7. The cross-section shows the outlet section 63 of the separator from the first outlet 53. The fluid or filtrate moves up between the tubular separator and the inner housing until it is spun out into the outlet point 63. Referring now to fig. 9, therein is shown a section B-B of fig. 7. The cross-section shows the outlet section 64 of the separator from the second outlet 52. The concentrated solids move upwardly between the tubular separator 59 and the outer housing until spun out into the outlet location 64.

Referring now to figure 10, the swirl inducing device 54, in the form of an impeller, is shown in greater detail, disposed on the outer surface of an inverted bell 65. The impeller 54 is shaped so that when turned it provides a degree of lift or automatic pumping action to the passing fluid, as well as rotation.

Figure 11 shows the swirl inducing device 54 and the inverted bell 65 in combination with the inlet of the separator 51. The inner rotating housing is typically disposed flush with surface 68.

Although a few preferred embodiments have been described in detail, it will be apparent to those skilled in the art that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention.

Claims (32)

1. A solids separator, comprising:

an elongated tubular rotatable housing rotatable about a central axis;

a fluid inlet at one end of said housing adapted to receive a fluid stream containing entrained solids;

first and second outlets at opposite ends of the housing;

wherein the rotating housing is effective to exert a radially outward force on entrained solids flowing through the separator to cause solids to be concentrated at the peripheral portion of the flow cross-section at the first and second outlets, and the first outlet is adapted to receive the interior of the flow cross-section and the second outlet is adapted to receive the peripheral portion of the flow cross-section containing concentrated solids, the solids separator comprising a swirl inducing device connected to the rotating housing, wherein the swirl inducing device assists in exerting a radially outward force on the entrained solids.

2. The solids separator of claim 1, wherein: the first and second outlets are defined by a tubular separator mounted longitudinally within the rotary housing such that the second outlet is defined between the tubular separator and the rotary housing and the first outlet is defined through the tubular separator.

3. The solids separator of claim 1 or claim 2, wherein: the tubular separator is rotatable, rotating at the same number of revolutions per minute as the rotating shell.

4. The solids separator of claim 1 or claim 2, wherein: the tubular separator rotates faster or slower than the rotating housing.

5. The solids separator of claim 1, wherein: the swirl inducing means is constituted by an impeller arranged in front of the rotating housing.

6. The solids separator of claim 1, wherein: the vortex inducing means rotates at the same rpm as the rotating housing.

7. The solids separator of claim 1, wherein: the solids separator includes an automated pumping device coupled to the rotating housing, wherein the automated pumping device facilitates pumping of fluid through the solids separator.

8. The solids separator of claim 7, wherein: the automatic pumping device is composed of an impeller and is arranged at the outlet of the rotating shell.

9. The solids separator of claim 7, wherein: the automatic pumping device rotates at the same rpm as the rotating housing.

10. The solids separator of claim 1, wherein: the angular velocity of the portion of the peripheral portion of the cross-section of the flow is substantially the same as the angular velocity of the rotating housing.

11. The solids separator of claim 1, wherein: the rotating housing rotates at a rotational speed of between 500 and 5000 revolutions per minute.

12. The solids separator of claim 1, wherein: the solids separator is oriented in a substantially vertical arrangement with a fluid inlet provided at the bottom of the arrangement.

13. The solids separator of claim 1, wherein: the flow rate of the fluid through the separator is such that there is minimal turbulence within the separator and the fluid flows through in a substantially laminar manner.

14. The solids separator of claim 1, wherein: the solids separator includes radially extending vanes mounted within the rotating housing, wherein the vanes assist in maintaining the angular velocity of the fluid and/or provide structural support to the solids separator.

15. The solids separator of claim 1, wherein: the solids separator includes a central shaft passing through the rotating housing, wherein the shaft disables fluid flow through the separator on the central shaft and/or provides structural support to the solids separator.

16. The solids separator of claim 1, wherein: the solids separator includes a housing enclosing a rotating housing.

17. A solids separator, comprising:

an elongated tubular outer housing rotatable about a central axis;

an elongated tubular inner housing mounted within said outer housing for rotation about said central axis to define a flow passage between said outer and inner housings;

a fluid inlet at one end of the flow passage and adapted to receive a fluid stream containing entrained solids;

first and second outlets at opposite ends of the flow passage;

wherein the rotatable outer and inner housings are effective to apply a radially outward force to entrained solids flowing through the flow passage to cause solids to be concentrated at peripheral portions of the flow cross-section at the first and second outlets, the first outlet being adapted to receive an inner portion of the flow cross-section and the second outlet being adapted to receive a peripheral portion of the flow cross-section of a stream containing concentrated solids, the solids separator comprising a swirl inducing device, wherein the swirl inducing device facilitates the application of a radially outward force to entrained solids.

18. The solids separator of claim 17, wherein: the outer housing rotates at the same rpm as the inner housing.

19. A solids separator according to claim 17 or 18, wherein: the first and second outlets are defined by a tubular separator mounted longitudinally between the outer and inner housings, whereby the second outlet is defined between the tubular separator and the outer housing and the first outlet is defined between the tubular separator and the inner housing.

20. The solids separator of claim 19, wherein: the tubular separator is rotatable and rotates at the same rpm as the outer or inner shell.

21. The solids separator of claim 17, wherein: the swirl inducing device is an impeller disposed on the outer surface of an inverted bell whose outermost circumference is connected to the peripheral edge of the inner housing near the inlet of the flow passage.

22. The solids separator of claim 21, wherein: the impeller also acts as an automatic pumping device to feed fluid into the flow passage.

23. The solids separator of claim 17, wherein: the angular velocity of the portion of the peripheral portion of the cross-section of the flow is substantially the same as the angular velocity of the outer housing.

24. The solids separator of claim 17, wherein: the outer and inner rotating shells rotate at a rotational speed of between 500 and 5000 revolutions per minute.

25. The solids separator of claim 17, wherein: the solids separator is oriented in a substantially vertical arrangement with a fluid inlet provided at the bottom of the arrangement.

26. The solids separator of claim 17, wherein: the flow rate of the fluid through the separator is such that there is minimal turbulence within the separator and the fluid flows through in a substantially laminar manner.

27. The solids separator of claim 17, wherein: the solids separator includes a central shaft passing through an inner rotating housing, wherein the shaft provides structural support to the solids separator.

28. The solids separator of claim 17, wherein: the solids separator includes a housing enclosing an outer rotating shell.

29. The solids separator of claim 1 or 17, wherein: the fluid is a liquid and the solids are particles present in the wastewater stream.

30. The solids separator of claim 1 or 17, wherein: the solids separator is used in place of a clarifier or settling tank or in place of or prior to any unit operation where solids settling rates are limited.

31. The solids separator of claim 1 or 17, wherein: the solids separator may be used to reduce the solids flux load of a clarifier operating in a biological wastewater treatment facility.

32. A solids separator, comprising:

a long tubular rotary housing rotatable about a central axis;

a fluid inlet at one end of said housing adapted to receive a fluid stream comprising entrained solids;

a plurality of outlets at opposite ends of said housing,

wherein the rotating housing is effective to apply a radially outward force to entrained solids flowing through the separator such that denser solids are located at a peripheral portion of the cross-section of the flow and lighter solids are located near the central axis, and the plurality of outlets are adapted to receive different portions of the cross-section of the flow, wherein the solids separator comprises a vortex inducing device coupled to the rotating housing, the vortex inducing device assisting in applying the radially outward force to the entrained solids.