An apparatus comprising a chamber enclosing a flow path of a first fluid and having a second inlet arranged downstream of the first inlet for receiving a second fluid. The apparatus further comprises a vertically adjustable throttle body an end portion comprising three parts, the first part being upstream of the second part, the third part being downstream of the second part, wherein, in an operating position, the second inlet is upstream of the third part of the throttle body and downstream of the first inlet and wherein the first part and the third part of the end portion are adapted to achieve a higher flow rate than the second part.

An arrangement and a method for controlling a gas flow separated from a suspension of medium consistency pulp. The pulp is treated in a pulp treatment apparatus including a first pump and a second pump, wherein the second pump is a degassing centrifugal pump provided with a degassing system including a degassing conduit in which a degassing valve is arranged for regulating a pressure difference between an inlet of the second pump and the degassing conduit. The degassing system further includes a pressurized degassing vessel working under overpressure and having an inlet and an outlet, wherein the outlet of the vessel is connected to a pressure control valve for maintaining a desired overpressure in the vessel.

A bleaching apparatus comprises a measurement chamber has a first substance, the amount of the first substance in the measurement chamber being known. A dosing unit inputs a second substance to the measurement chamber for causing a chemical reaction between the first substance and the second substance, one of the first substance and the second substance being chlorine dioxide and another of the first substance and the second substance being filtered sample from pulp slurry of a pulp process. At least one sensor performs detection of a property known to depend on the chemical reaction between the first substance and the second substance as a function of time. A data processing unit determines chemical demand of chlorine dioxide for washing loss in a bleaching sub-process on the basis of at least one value in the detected property within a known period of time after the input of the second substance.

A method for controlling a gas flow separated from a suspension of medium consistency pulp. The pulp is treated in a pulp treatment apparatus including a first pump and a second pump, wherein the second pump is a degassing centrifugal pump provided with a degassing system which includes a degassing conduit in which a degassing valve is arranged for regulating a pressure difference between an inlet of the second pump and the degassing conduit. The degassing system also includes a pressurized degassing vessel working under overpressure and having an inlet and an outlet, wherein the outlet of the vessel is connected to a pressure control valve for maintaining a desired overpressure in the vessel.

A method of producing high yield chemical cellulosic pulp includes: (a) chemically pulping wood chips to separate lignin and liberate cellulosic fibers from the wood chips to generate a cellulosic pulp; (b) washing and screening the pulp of step (a); (c) pre-treating the washed pulp with oxygen; (d) optionally washing the treated pulp of step (c); (e) bleaching the pre-treated pulp in an extended duration oxidative bleaching stage; (f) optionally washing the bleached pulp of step (e); and (g) optionally further oxidatively or reductively bleaching the bleached pulp in a shorter duration bleaching stage, wherein the bleached pulp is produced at a yield of greater than 60% based on the weight of the pulped wood chips (dry basis).

The present invention provides a method of producing an improved cellulose pulp consisting of cellulose fibers of a desired length, such as cellulose fibers having a length-weighted average fiber length Lc(l)>0.6 mm and its use in cellulose pulp-comprising products, such as packaging material with improved properties.