Abstract: A solution of cellulose is formed by moving a premix of a tertiary amine N-oxide, water and cellulose through a thin-film evaporator using a bladed rotor under treatment conditions which specify, inter alia, an area of heated surface (1 m.sup.2 to 125 m.sup.2), a blade speed (2.5 to 8 m/sec), a pressure (25 to 100 mb) and a temperature (90.degree. to 135.degree. C.).

Abstract: A dump tank for receiving congealable material vented from a chemical process, the dump tank having two access doors covering two access ports, both doors being openable for cleaning purposes so that congealable material vented into the tank can be pushed out of one access port from the other port.

Abstract: A jet assembly for spinning cellulose fibres from a solution of cellulose in an amine oxide solvent in which the jet assembly includes a generally top-hat shaped spinnerette having a series of downwardly directed holes through the base of the spinnerette and an outwardly directed flange around the periphery of the vertical walls of the spinnerette, the jet assembly including a heated housing engaging with the flange and being bolted to the flange, insulation being provided on the underside of the jet assembly over the outer periphery, the combination of heating and insulation regulating the temperature of the jet assembly for optimum spinning of an amine oxide cellulose solution.

Abstract: Continuous elongate members such as filaments are produced by forming a hot dope of cellulose, amine oxide and water, extruding the dope through a die assembly and precipitating the cellulose to form the bodies and maintaining the concentration of the dope at a predetermined value by monitoring the refractive index of the dope before it is extruded.

Abstract: A premix storage hopper for storing a hot, viscous, paste-like mixture containing cellulose dispersed in a solution of tertiary amine oxide and water, comprises a vertical contain having a central shaft rotatable about a vertical axis and carrying stirring members and heating means for heating side walls of the container.

Abstract: A method is disclosed of forming a premix which is suitable for conversion into a cellulosic dope which can be used to produce cellulosic products. The method involves introducing into a mixing chamber predetermined quantities of shredded cellulosic material and a solution of amine oxide at an elevated temperature and stirring the mixture for a period of time by rotating mixer blades within the mixing chamber at a speed of between 40 and 80 r.p.m..

Abstract: In a process for making solvent-spun cellulose fibre, cellulose is dissolved in aqueous N-methylmorpholine N-oxide to form a solution, said solution is passed through at least one pipe, the temperature in degrees Centigrade of said solution in the center of said pipe being controlled at 1000/(X+0.98.sqroot.D) and/or the temperature of said solution at the interior wall of said pipe being controlled at 1000/(Y+1.15.sqroot.D) where D represents the internal diameter of said pipe in inches, X represents a value equal to or greater than 5.0 and Y represents a value equal to or greater than 5.4, and said solution is subsequently extruded through a die to form filaments which are coagulated, washed with water to remove said solvent and then dried, thereby forming said solvent-spun cellulose fibre.

Abstract: The concentration of a dope of cellulose/amine oxide/water for use in the manufacture of continuous filaments of cellulose is controlled by measuring its refractive index and adjusting the water content to maintain the refractive index within specified limits.

Abstract: A method for transporting a solution of cellulose in aqueous N-methylmorpholine N-oxide through a pipe, the temperature in degrees centigrade of said solution in the center of said pipe being controlled at 1000/(X+0.98 x.sqroot.D) and/or the temperature of said solution at the interior wall of said pipe being controlled at 1000/(Y+1.15 x.sqroot.D) where D represents the internal diameter of the pipe in inches, X represents a value equal to or greater than 5.0, and Y represents a value equal to or greater than 5.4.