Degassing centrifugal apparatus with energy recovery, process for degassing a fluid and process for producing paper or board

Claim 2

A degassing centrifugal apparatus comprising a rotatable hollow rotor ( 20 ) connected to a fluid inlet ( 14 ) at one end and a liquid outlet ( 16 ) at the opposite end, and having a gas exhaust ( 36 ) connected to the center thereof, said apparatus having at its inlet end means for bringing a fluid to rotate on the inner wall of said rotor ( 20 ) and at its outlet end a turbine ( 30 ) adapted to be driven by liquid separated from said fluid and flowing from said rotor ( 20 ), wherein said turbine ( 30 ) is configured to recover at least a portion of the dynamic energy contained in a fluid flowing in said rotor ( 20 ).

Claim 3

The apparatus according to claim 1 wherein said turbine ( 30 ) forms part of said rotor structure and is rotatable with said rotor ( 20 ).

Claim 4

The apparatus according to claim 2 wherein said turbine ( 30 ) is located in a pumping zone formed in said rotor ( 20 ) at its outlet end.

Claim 5

The apparatus according to claim 3 wherein said pumping zone contains a turbine wheel ( 30 ) extending into a stationary liquid outlet ( 16 ).

Claim 6

The apparatus according to claim 4 wherein said turbine wheel ( 30 ) comprises shovels ( 32 ) forming between themselves arcuate channels ( 33 ) which are narrower at the outer periphery than at the inner periphery thereof.

Claim 7

The apparatus according to claim 1 , wherein said hollow rotor ( 20 ) comprises an elongated tubular or conical gas separation drum ( 34 ) of an essentially circular cross-section.

Claim 8

A process for degassing a fluid by centrifuging, comprising feeding a fluid containing a mixture of liquid and gas into an inlet of a rotating hollow rotor, bringing said fluid to rotate on an inner wall of said rotor, bringing said fluid to flow axially towards a liquid outlet at the opposite end of said rotor while causing said gas to separate from said liquid, directing the resulting degassed liquid into a turbine at said opposite end of said rotor, discharging said degassed liquid through said turbine, and discharging said gas through a central gas exhaust.

Claim 9

A process for degassing a fluid by centrifuging, comprising feeding a fluid containing a mixture of liquid and gas into an inlet of a rotating hollow rotor, bringing said fluid to rotate on an inner wall of said rotor, bringing said fluid to flow axially towards a liquid outlet at the opposite end of said rotor while causing said gas to separate from said liquid, directing the resulting degassed liquid into a turbine at said opposite end of said rotor, discharging said degassed liquid through said turbine, and discharging said gas through a central gas exhaust.

Claim 10

The process according to claim 7 , wherein said degassed liquid is discharged peripherically from said turbine at a pumping pressure.

Claim 11

The process according to claim 7 , wherein said turbine recovers dynamic energy from said degassed liquid.

Claim 12

A process for producing paper or board in a paper machine including the steps of providing a papermaking stock of pulp; diluting said stock in one or more stages with backwater drained through a forming wire of said paper machine; feeding said stock through a head box of said paper machine onto said forming wire; forming a web on said forming wire while allowing water from said stock to drain through said wire; feeding said web through a press section and a drying section of said paper machine to provide paper or board, characterized in that at least a portion of said backwater and/or diluted stock is pumped with at least one degassing centrifugal apparatus comprising a rotatable hollow rotor ( 20 ) connected to an inlet ( 14 ) for said backwater or stock at one end and an outlet ( 16 ) for degassed backwater or stock at the opposite end, and having a gas exhaust ( 36 ) connected to the center thereof, said apparatus having at its inlet end means for bringing said backwater or stock to rotate on the inner wall of said rotor ( 20 ), and at its outlet end a turbine ( 30 ) for recovering energy from said rotating backwater or stock.

Claim 13

A process for producing paper or board in a paper machine including the steps of providing a papermaking stock of pulp; diluting said stock in one or more stages with backwater drained through a forming wire of said paper machine; feeding said stock through a head box of said paper machine onto said forming wire; forming a web on said forming wire while allowing water from said stock to drain through said wire; feeding said web through a press section and a drying section of said paper machine to provide paper or board, characterized in that at least a portion of said backwater and/or diluted stock is pumped with at least one degassing centrifugal apparatus comprising a rotatable hollow rotor ( 20 ) connected to an inlet ( 14 ) for said backwater or stock at one end and an outlet ( 16 ) for degassed backwater or stock at the opposite end, and having a gas exhaust ( 36 ) connected to the center thereof, said apparatus having at its inlet end means for bringing said backwater or stock to rotate on the inner wall of said rotor ( 20 ), and at its outlet end a turbine ( 30 ) for recovering energy from said rotating backwater or stock.