Claims
- 1. In a mass transfer column having an external column shell and a plurality of trays in vertically spaced relationship, said trays having at least one opening for accommodating the passage of liquid to the next lower tray, the improvement comprising:
- a liquid confining structure of mesh or screen material extending from said opening in a first tray to a point above a second lower tray, said mesh or screen material being liquid permeable to permit liquid to exit the liquid confining structure by passing through the mesh or screen material and having a sufficiently high capillarity to present a substantially vapor-impervious barrier when wetted with a liquid during operation of the mass transfer column to impede passage of vapor through the mesh or screen material.
- 2. The mass transfer column as set forth in claim 1, wherein said liquid confining structure comprises a cylinder.
- 3. The mass transfer column as set forth in claim 1, wherein said liquid confining structure terminates at a point above a level at which liquid accumulates on said second lower tray.
- 4. The mass transfer column as set forth in claim 1, wherein said liquid confining structure comprises a planar wall which is juxtaposed in relation to the external column shell wall to present a downcomer for liquid flowing from said first tray to said second lower tray.
- 5. The mass transfer column as set forth in claim 1, wherein said liquid confining structure terminates at a point below a level at which liquid accumulates on said second lower tray.
- 6. The mass transfer column as set forth in claim 1, wherein said liquid confining structure is polygonal or segmental in horizontal cross section.
- 7. A mass transfer column comprising an external shell and a plurality of tray and downcomer structures in vertically spaced relationship within said shell, at least one of said tray and downcomer structures comprising:
- a tray having a plurality of openings for permitting the upward passage of vapor; and
- a downcomer associated with and extending below the tray to remove liquid from said tray and feed it to a lower tray and downcomer structure, said downcomer having one wall extending downwardly from said tray toward said lower tray and downcomer structure, at least a portion of said one wall comprising a first sheet of liquid permeable material being constructed to permit liquid to exit the downcomer by passing through said first sheet of liquid permeable material and to present a substantially vapor-impervious barrier when wetted with a liquid during operation of the mass transfer column to impede passage of vapor through the first sheet of liquid permeable material.
- 8. The mass transfer column as set forth in claim 7, wherein a bottom discharge outlet of said downcomer terminates at a point above a level of accumulated liquid on said lower tray.
- 9. The mass transfer column as set forth in claim 8, including a sheet of liquid permeable material closing said bottom discharge outlet of said downcomer.
- 10. The mass transfer column as set forth in claim 8, including a plate closing said bottom discharge outlet of said downcomer and presenting openings for passage of liquid.
- 11. The mass transfer column as set forth in claim 10, wherein said plate includes louvres associated with said openings to impart a horizontal directional flow to liquid passing through said louvres.
- 12. The mass transfer column as set forth in claim 7, wherein said one wall of the downcomer is formed of a sheet of mesh or screen material.
- 13. The mass transfer column as set forth in claim 7, wherein at least a portion of said one wall of the downcomer is sloped at an angle to the vertical.
- 14. The mass transfer column as set forth in claim 7, wherein said downcomer includes other walls joined with said one wall to form liquid confining structure.
- 15. The mass transfer column as set forth in claim 14, wherein said column shell forms at least a portion of said other walls of the downcomer.
- 16. The mass transfer column as set forth in claim 14, wherein said other walls of the downcomer are spaced from the column shell.
- 17. A mass transfer column comprising an external shell and a plurality of tray and downcorner structures in vertically spaced relationship within said shell, at least one of said tray and downcomer structures comprising:
- a tray having a plurality of openings for permitting the upward passage of vapor; and
- a downcomer associated with and extending below the tray to remove liquid from said tray and feed it to a lower tray and downcomer structure, said downcomer having one wall extending downwardly from said tray toward said lower tray and downcomer structure, at least a portion of said one wall comprising a first sheet of liquid permeable material being constructed to present a substantially vapor-impervious barrier when wetted with a liquid during operation of the mass transfer column,
- wherein said one wall of the downcomer includes a second sheet of liquid permeable material having a different liquid permeability than said first sheet.
- 18. A mass transfer column comprising an external shell and a plurality of tray and downcomer structures in vertically spaced relationship within said shell, at least one of said tray and downcomer structures comprising:
- a tray having a plurality of openings for permitting the upward passage of vapor; and
- a downcomer associated with and extending below the tray to remove liquid from said tray and feed it to a lower tray and downcomer structure, said downcomer having one wall extending downwardly from said tray toward said lower tray and downcomer structure, at least a portion of said one wall being sloped at an angle to the vertical and comprising a sheet of liquid permeable material being constructed to present a substantially vapor-impervious barrier when wetted with a liquid during operation of the mass transfer column,
- wherein said downcomer includes other walls joined with said one wall to form a liquid confining structure, at least a portion of said other walls comprising a liquid permeable material being constructed to present a substantially vapor-impervious barrier when wetted with a liquid during operation of the mass transfer column.
Parent Case Info
This is a continuation-in-part of U.S. application Ser. No. 08/135,921, filed Oct. 13, 1993, now U.S. Pat. No. 5,496,446, which is a division of U.S. application Ser. No. 07/962,254, filed Oct. 16, 1992, now U.S. Pat. No. 5,454,913, which is a continuation-in-part of U.S. application Ser. No. 07/775,010, filed Oct. 11, 1991, now U.S. Pat. No. 5,291,989, which is a continuation of U.S. application Ser. No. 07/475,971, filed Feb. 6, 1990, now U.S. Pat. No. 5,108,550.
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Divisions (1)
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Number |
Date |
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962254 |
Oct 1992 |
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Continuations (1)
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Date |
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475971 |
Feb 1990 |
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Continuation in Parts (2)
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Number |
Date |
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135921 |
Oct 1993 |
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Parent |
775010 |
Oct 1991 |
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