Abstract: A non-woven web of fibrous material is produced using a moving foraminous element in the practice of the foam process. A first foam slurry of air, water, fibers and a surfactant is generated and centrifugally pumped into contact with the moving foraminous element. Substantially fiber-free foam is withdrawn from the foraminous element while forming a non-woven web of fibrous material on the foraminous element, and at least a part of the substantially fiber-free foam is used in the generation of the first foam slurry. Recycling is also typically practiced using a centrifugal pump, and the centrifugal pumps are preferably degassing pumps which remove some of the gas from the foam. By practicing the invention it is possible to produce fibrous webs using the foam process that are more than two meters wide, and at a forming speed of more than about 100 m/min (e.g. about 200-500 m/min).

Abstract: A non-woven web of fibrous material is produced using a moving foraminous element in the practice of the foam process. A first foam slurry of air, water, fibers and a surfactant is generated and centrifugally pumped into contact with the moving foraminous element. Substantially fiber-free foam is withdrawn from the foraminous element while forming a non-woven web of fibrous material on the foraminous element, and at least a part of the substantially fiber-free foam is used in the generation of the first foam slurry. Recycling is also typically practiced using a centrifugal pump, and the centrifugal pumps are preferably degassing pumps which remove some of the gas from the foam. By practicing the invention it is possible to produce fibrous webs using the foam process that are more than two meters wide, and at a forming speed of more than about 100 m/min (e.g. about 200-500 m/min).

Abstract: A non-woven web of fibrous material is produced using a moving foraminous element in the practice of the foam process. A first foam slurry of air, water, fibers and a surfactant is generated and centrifugally pumped into contact with the moving foraminous element. Substantially fiber-free foam is withdrawn from the foraminous element while forming a non-woven web of fibrous material on the foraminous element, and at least a part of the substantially fiber-free foam is used in the generation of the first foam slurry. Recycling is also typically practiced using a centrifugal pump, and the centrifugal pumps are preferably degassing pumps which remove some of the gas from the foam. By practicing the invention it is possible to produce fibrous webs using the foam process that are more than two meters wide, and at a forming speed of more than about 100 m/min (e.g. about 200-500 m/min).

Abstract: The present invention relates to a method and an apparatus for separating gas from solids-containing liquid. The apparatus in accordance with the invention may be applied in such places where air is separated from a medium by means of reduced pressure or vacuum condition. The apparatus in accordance with the present invention is especially applicable for the pulp and paper industry in situations where gas has been separated from the fiber suspension, but where the gas contains some fibers or other solids, which must be separated from the gas flow prior to the vacuum pump generating suction. The method in accordance with the present invention is characterized in that the fraction containing gas, liquid and solid material is passed from the pulp treatment apparatus to a separate separating apparatus, solids are separated from that fraction, which are then discharged from the separation apparatus.

Abstract: A system for simultaneously degassing and pumping a liquid from a source includes in combination a gaseous liquid source having a feed inlet for the liquid so as to form a liquid surface at a first level; a degassing pump for simultaneously degassing and pumping the liquid, the degassing pump includes a housing with a liquid inlet, and an outlet for a substantially gas-free flow and a gas discharge opening, a suction conduit having a first end connected to the pump inlet and a second outlet immersed in the liquid below the liquid surface. Preferably, the suction conduit is immersed in the liquid flow below the liquid surface and below the feed inlet.

Abstract: A method of separating an aqueous solids containing suspension includes (a) subjecting a first solids containing suspension to centrifugal forces so as to separate the suspension into a first gas containing flow, a second gas-free flow and a third flow; (b) feeding the third flow into a flotation cell having a bottom; (c) introducing air at the bottom of the flotation cell into the third flow for separating from the third flow a fourth partial flow; (d) withdrawing the air containing third flow after the separation of the fourth partial flow from the flotation cell; and (e) subjecting the third flow to the centrifugal forces of step (a).

Abstract: A method and apparatus for improving the treatment of a gas containing fiber suspension in the pulp and paper industry, especially for increasing the capacity of a screening department, a washing department, a thickening department, a press, a curved screen, or the like, includes the simultaneous separation and removal of the gases prior to the respective treatment stage.

Abstract: A pump for pumping an air containing medium includes rear vanes (11) on the propeller back plate of the pump and a back ball arranged so that a radially widening space is created between the impeller back plate and the rear wall for guiding the flow of the medium, generated by the combined effect of forces with different directions and different intensities directed at the medium in the spaces between the rear vanes, past gas discharge opening (12) in the rear wall of the pump or for retarding the flow thereby preventing the flow from entering the gas discharge opening (12).

Abstract: A method of and an apparatus for separating gas from a gas containing suspension, generally a liquid medium, which may contain solid material, such as fibers in the pulp and paper industry. At least a portion of the suspension is first subjected to the centrifugal action of a centrifugal pump and then to further centrifugal separation of a centrifugal separator so as to divide the suspension at least once into two fractions, of which the heavier fraction containing less gas is discharged from the apparatus and the lighter fraction containing more gas is returned back to the suction side of the centrifugal pump.The apparatus is characterized in that the casing of the centrifugal pump is connected to a centrifugal separator for dividing the suspension into two fractions, the separator having a conduit for the discharge of the heavier fraction from the separator and a conduit for returning the lighter fraction to a channel leading to the suction side of the pump.

Abstract: The method and apparatus include that the rear vanes (11) of the pump or the members operating therewith are arranged so that they either direct the flow of the medium, generated by the combined effect of forces with different directions and different intensities directed at the medium in the space behind the impeller in the vane gaps of said rear vanes, past gas discharge opening (12) in the rear wall of the pump or they slow down said flow so that its extension to said gas discharge opening (12) is prevented.

Abstract: A centrifugal pump for separating an entrained gas from a working fluid in which the pump housing has a hollow chamber therein, an axially extending inlet into the chamber, an outlet leading out of the chamber, and a gas vent for the chamber; a rotatable shaft mounted in the housing in axial alignment with the inlet; an impeller is disposed in the chamber and mounted on the shaft for rotation therewith, the impeller includes a plate for dividing the chamber into a first chamber portion communicating with the inlet and outlet and a second chamber portion communicating with the vent. The plate has an aperture extending therethrough for allowing the passing of working fluid and gas therethrough; and is further provided with at least one pumping vane disposed in the chamber portion for pumping the working fluid into the first chamber portion through the inlet and out of the first chamber portion through the outlet.