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EP-4735145-A1 - BELT FILTER

EP4735145A1EP 4735145 A1EP4735145 A1EP 4735145A1EP-4735145-A1

Abstract

A belt filter (1) for removing particles from a fluid comprises a vessel (10), a continuous screen belt (32) forming a loop having an upper surface and a lower surface, and a support structure (34, 36) being adapted to drive the continuous screen belt (32). A belt cleaning device (40) is provided below the lower surface of the belt (32) and comprises a transverse shaft (42) having a mantle surface, and a plurality of cleaning elements (44) attached to the shaft (42). Each of the cleaning elements (44) comprises an elongated member having a longitudinal extension along the shaft (42), and a radial extension away from the mantel surface of the shaft (42), wherein the radial extension is equal to or less than a distance between the mantle surface of the shaft and the lower surface of the screen belt (32), an efficient and careful cleaning of the belt is provided.

Inventors

  • Jonsson, Linus
  • HEDIN, Martin
  • Billerdahl, Nicklas

Assignees

  • Sulzer Management AG

Dates

Publication Date
20260506
Application Date
20240627

Claims (16)

  1. 1 . A belt filter (1 ) for removing particles from a fluid, comprising: - a vessel (10) with a fluid inlet pipe (22) at a first end of the vessel and an outlet (24) for particles removed from the fluid at a second end of the vessel opposite to the first end, - a continuous screen belt (32) forming a loop having an upper surface and a lower surface, - a support structure (34, 36) being adapted to, during operation, drive the continuous screen belt (32) such that the upper surface is moved in a direction from the first end of the vessel to the second end of the vessel (10), - a belt cleaning device (40) provided below the lower surface of the continuous screen belt (32), the belt cleaning device (40) comprising a shaft (42) having a mantle surface, the shaft extending across the lower surface of the continuous screen belt (32), and a plurality of cleaning elements (44) attached to the mantle surface of the shaft (42), c h aracte ri zed i n th at - each of the cleaning elements (44) comprises an elongated member having a longitudinal extension along the shaft (42), and a radial extension (R) away from the mantel surface (42a) of the shaft (42), - wherein the radial extension, during rotation of the shaft (42), is equal to or less than a distance between the mantle surface of the shaft and the lower surface of the screen belt (32).
  2. 2. The belt filter according to claim 1 , wherein the radial extension of the cleaning elements (44) is such that the distance between the cleaning elements (44) and the lower surface of the screen belt (32) is 0-15 millimetres, even more preferably 1-15 millimetres, most preferably 1-10 millimetres.
  3. 3. The belt filter according to claim 1 or 2, wherein the belt cleaning device (40) is provided essentially below the drive roller (34).
  4. 4. The belt filter according to any one of claims 1-3, wherein the belt cleaning device (40), during operation, is adapted to rotate in a direction opposite to the direction of motion of the lower surface of the screen belt (32).
  5. 5. The belt filter according to any one of claims 1-4, wherein the cleaning elements (44) have the form of mutually parallel vanes.
  6. 6. The belt filter according to any one of claims 1-5, wherein the cleaning elements (44) are arranged in parallel with the shaft (42) of the belt cleaning device (40).
  7. 7. The belt filter according to any one of claims 1-5, wherein the cleaning elements (44) extend helically along the shaft (42) of the belt cleaning device (40).
  8. 8. The belt filter according to any one of claims 1-7, wherein the plurality of cleaning elements (44) the belt cleaning device (40) are uniformly distributed around the shaft (42) of the belt cleaning device (40).
  9. 9. The belt filter according to any one of claims 1-8, wherein the number of cleaning elements (44) of the belt cleaning device (40) is any of the following: four, six, and eight.
  10. 10. The belt filter according to any one of claims 1 -9, wherein the cleaning elements (44) are made of a resilient material, preferably rubber or resilient plastics.
  11. 11 . The belt filter according to any one of claims 1 -10, wherein two adjacent cleaning elements (44) are part of the same cleaning element unit, the cleaning element unit comprising a mounting portion (46) interconnecting two cleaning elements (44).
  12. 12. The belt filter according to claim 11 . wherein the belt cleaning device (40) comprises a plurality of attachment pieces (48), each attachment piece (48) being placed above a respective mounting portion (46) of cleaning element unit so that the mounting portion (46) is provided between the shaft (42) and the attachment piece (48).
  13. 13. The belt filter according to any one of claims 1 -12, wherein radially outer edges of the cleaning elements (44), during operation, are adapted to move above the lower surface of the screen belt (32) at a speed of between 1 .0 and 3.0 meters per second, even more preferably at a speed of between 1 .8 and 2.2 meters per second, relatively to the lower surface of the screen belt (32).
  14. 14. The belt filter according to any one of claims 1 -13, wherein the screen belt (32) is constructed of polyester.
  15. 15. The belt filter according to any one of claims 1 -14, wherein the screen belt (32) has a mesh opening size of 100-1000 pm.
  16. 16. The belt filter according to any one of claims 1 -15, wherein screen belt (32), during operation, is adapted to move at a linear velocity of 400 centimetres per minute, more preferably at a linear velocity of from 200 centimetres per minute to about 1500 centimetres per minute.

Description

BELT FILTER Technical field [0001] The present invention relates generally to belt filters and more particularly to a belt filter with an improved belt cleaning capability. Background art [0002] So-called belt filters are known for removing or separating particles from a fluid, such as water, in a cost-effective and space-efficient way, for example in municipal waste water and sedimentation processes. Other application areas are fish farming and fish processing. By means of a belt filter, a dry sludge is provided without the need for added chemicals. [0003] A prior art belt filter works according to the following general principles. Untreated water or other fluid to be treated is led into the filter and particles are separated when the water passes through a screen belt. This screen belt rotates when it needs cleaning. The belt is cleaned principally by brush and then flushed at a high pressure. Alternatively, the belt can be cleaned by air. The particles separated by the brush are transported internally in the filter to a press that dewaters the sludge to a very high dry content. The waste water is drained out of the filter separately and can normally be led back to the incoming water. [0004] A drawback with using a brush for cleaning the belt is the wear caused by the contact between the bristles and the belt. Also, the brush gets clogged and needs frequent cleaning for proper function. Summary of invention [0005] An object of the present invention is therefore to provide a belt filter with an improved cleaning function. [0006] According to the invention, a belt filter for removing particles from a fluid is provided, the belt filter comprising a vessel with a fluid inlet pipe at a first end of the vessel and an outlet for particles removed from the fluid at a second end of the vessel opposite to the first end, a continuous screen belt (32) forming a loop having an upper surface and a lower surface, a support structure being adapted to, during operation, drive the continuous screen belt such that the upper surface is moved in a direction from the first end of the vessel to the second end of the vessel, a belt cleaning device provided below the lower surface of the continuous screen belt, the belt cleaning device comprising a shaft having a mantle surface, the shaft extending across the lower surface of the continuous screen belt, and a plurality of cleaning elements attached to the mantle surface of the shaft, the belt filter being characterized in that each of the cleaning elements comprises an elongated member having an longitudinal extension along the shaft, and a radial extension away from the mantel surface of the shaft, wherein the radial extension, during rotation of the shaft, is equal to or less than a distance between the mantle surface of the shaft and the lower surface of the screen belt. [0007] In a preferred embodiment, the radial extension of the cleaning elements is such that the distance between the cleaning elements and the lower surface of the screen belt is 0-15 millimetres, even more preferably 1-15 millimetres, most preferably 1-10 millimetres. [0008] In a preferred embodiment, the belt cleaning device is provided essentially below the drive roller. [0009] In a preferred embodiment, the belt cleaning device, during operation, is adapted to rotate in a direction opposite to the direction of motion of the lower surface of the screen belt. [0010] In a preferred embodiment, the cleaning elements have the form of mutually parallel vanes. [0011] In a preferred embodiment, the cleaning elements are arranged in parallel with the shaft of the belt cleaning device. Alternatively, the cleaning elements extend helically along the shaft of the belt cleaning device. [0012] In a preferred embodiment, the plurality of cleaning elements of the belt cleaning device is uniformly distributed around the shaft of the belt cleaning device. [0013] In a preferred embodiment, the number of cleaning elements of the belt cleaning device is any of the following: four, six, and eight. [0014] In a preferred embodiment, the cleaning elements are made of a resilient material, preferably rubber or resilient plastics. [0015] In a preferred embodiment, two adjacent cleaning elements are part of the same cleaning element unit, the cleaning element unit comprising a mounting portion interconnecting two cleaning elements. In this preferred embodiment, the belt cleaning device preferably comprises a plurality of attachment pieces, each attachment piece being placed above a respective mounting portion of cleaning element unit so that the mounting portion is provided between the shaft and the attachment piece. [0016] In a preferred embodiment, radially outer edges of the cleaning elements, during operation, are adapted to move above the lower surface of the screen belt at a speed of between 1 .0 and 3.0 meters per second, even more preferably at a speed of between 1.8 and 2.2 meters per second, relatively to the lower sur