Claims
- 1. A process for removal of interfering materials from an aqueous fibrous pulp suspension, comprising:
generating gas bubbles; collecting the interfering materials by use of the gas bubbles; and removing the interfering materials with a flotation foam, wherein the fibrous pulp suspension and the gas bubbles are introduced into a flotation layer having a maximum thickness of approximately 100 mm so as to separate the gas bubbles and the fibrous pulp suspension, and wherein the gas bubbles are admixed with the fibrous pulp suspension before the fibrous pulp suspension enters the flotation layer.
- 2. A process in accordance with claim 1, wherein the flotation layer has a maximum thickness of approximately 50 mm.
- 3. A process in accordance with claim 1, wherein the gas bubbles are mainly air bubbles.
- 4. A process in accordance with claim 1, wherein the gas bubbles are provided by a gas that is lighter than air.
- 5. A process in accordance with claim 1, wherein the fibrous pulp suspension has a fiber pulp content of at least approximately 2% by weight in the flotation layer.
- 6. A process in accordance with claim 1, including diluting the fibrous pulp suspension after addition of the gas bubbles and transformation into the flotation layer.
- 7. A process in accordance with claim 1, wherein the gas bubbles are of different sizes and are added to the flotation layer, whereby bubble size varies in a direction of flow of the suspension.
- 8. A process in accordance with claim 1, including adding gas bubbles of different sizes to the flotation layer, whereby the size varies in a rising direction of the gas bubbles.
- 9. A process in accordance with claim 1, further comprising:
creating a local turbulence in a separation region of the flotation layer, the separation region being between the suspension and the flotation foam.
- 10. A process in accordance with claim 1, wherein the flotation layer extends at least approximately 150 mm in a flow direction of the flotation layer.
- 11. A process in accordance with claim 1, including subjecting the fibrous pulp suspension to an initial processing in which the fibrous pulp suspension is fed at a height that is greater than a thickness of the flotation layer.
- 12. A process in accordance with claim 11, wherein the flotation layer extends in the direction of flow to a length of between approximately 1 mm and approximately 500 mm.
- 13. A process in accordance with claim 11, including creating micro-turbulence in the fibrous pulp suspension before the initial processing.
- 14. A process in accordance with claim 11, wherein the fibrous pulp suspension is accelerated to at least twice an average flow velocity during the entry into the flotation layer.
- 15. A process in accordance with claim 1, wherein a cleaned suspension is diverted immediately down-stream of the flotation layer.
- 16. A process in accordance with claim 1, wherein the separation takes place in a gravity field that is greater than Earth's gravity.
- 17. A process in accordance with claim 16, wherein the separation is executed in a flotation cyclone.
- 18. A process in accordance with claim 17, wherein a portion of the gas bubbles is added to the suspension before entry into the flotation cyclone and remaining portion of the gas bubbles is added afterward.
- 19. A process in accordance with claim 17, wherein the separation is executed in a centrifuge.
- 20. A process for removal of interfering materials from an aqueous fibrous pulp suspension, comprising:
generating gas bubbles; collecting the interfering materials by use of the gas bubbles; and removing the interfering materials with a flotation foam; wherein the fibrous pulp suspension and the gas bubbles are introduced into a flotation layer so as to separate the gas bubbles and the fibrous pulp suspension, and wherein vibrations are transmitted to the flotation layer.
- 21. A process in accordance with claim 20, wherein the vibrations are transmitted by shaking at least part of a flotation element that is in contact with the flotation layer.
- 22. A process in accordance with claim 20, wherein the vibrations are transmitted to the fibrous pulp suspension by an agitating element.
- 23. A process in accordance with claim 20, wherein the vibrations are transmitted to the fibrous pulp suspension by hydraulic impulses.
- 24. A process in accordance with claim 20, wherein the vibrations are transmitted to the fibrous pulp suspension by pneumatic impulses.
- 25. A process in accordance with claim 24, including applying the pneumatic impulses to a gas provided to supply the gas bubbles.
- 26. A flotation apparatus, comprising:
a flotation vessel which receives a fibrous pulp suspension to be cleaned; an inlet for receiving the suspension; an outlet for discharging cleaned fibrous pulp suspension; and a skimmer element for separation of flotation foam from the suspension, wherein the skimmer element separates a flotation chamber receiving the fibrous pulp suspension by setting a filling height that does not exceed approximately 100 mm.
- 27. A flotation device in accordance with claim 26, wherein the flotation chamber is substantially planar.
- 28. A flotation device in accordance with claim 26, wherein the flotation chamber has a corrugated bottom wall, corrugations of the wall extend perpendicular to a flow direction of the fibrous pulp suspension.
- 29. A flotation device in accordance with claim 28, wherein gas supply pipes are located on the corrugated bottom wall so as to add gas bubbles to parts of flotation layers of the fibrous pulp suspension, the gas bubbles being added to the flotation layers having a predetermined depth.
- 30. A flotation device in accordance with claim 26, wherein the flotation chamber is inclined towards the skimmer device for the flotation foam.
- 31. A flotation device in accordance with claim 26, wherein a gas supply box extends along the flotation chamber at least over a portion of a flow path of the suspension.
- 32. A flotation device in accordance with claim 31, wherein a wall having a number of openings is positioned between the gas supply box and the flotation chamber.
- 33. A flotation device in accordance with claim 32, wherein the wall is a perforated plate.
- 34. A flotation device in accordance with claim 32, wherein the wall is a flexible fabric.
- 35. A flotation device in accordance with claim 31, wherein an air supply is connected to the gas supply box to feed a pulsating flow of gas to the fibrous pulp suspension.
Priority Claims (1)
Number |
Date |
Country |
Kind |
197304648 |
Jul 1997 |
DE |
|
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application is a continuation of U.S. patent application Ser. No. 08/115,672 filed Jul. 15, 1998, which claims the priority under 35 U.S.C. 119 of German Patent Application No. 197 30 464.8, filed on Jul. 16, 1997, the disclosures of which are expressly incorporated by reference herein in their entireties.
Continuations (1)
|
Number |
Date |
Country |
Parent |
08115672 |
Sep 1993 |
US |
Child |
09810672 |
Mar 2001 |
US |