The invention relates to a system of producing MFC (micro fibrillated cellulose) having a process device (30) of a pulper, a refiner or a screen configured to process MFC suspension to consistency of 0.5-5%. The system has a continuous pressing means (15; 25, 26) configured to dry the MFC suspension to a consistency of 6-60%. A method of producing MFC has at least one process stage (30) which processes a MFC suspension to a consistency of 0.5-5% by a process device (30). In the process stage the MFC suspension is pulped in a pulping stage in a pulper and/or refined in a refining stage by a refiner and/or screened in a screening stage by a screen. The MFC suspension having the consistency of 0.5-5% is dried in a drying stage of continuous pressing (15, 25, 26) by continuous a pressing device (15, 25, 26) to a consistency of 6-60%.

The present invention provides a method and system for measuring disintegration of a fibrous product. The method comprises disintegration of a sample of the fibrous product in an aqueous solution, optionally promoted by mechanical energy, passing the aqueous solution through a screen to obtain a permeate and retained fraction on the screen, and analyzing at least one parameter from the permeate for example by a gravimetric analysis, an optical analysis, an electrochemical analysis, a volumetric analysis, or combination thereof. Advantages include adjustability, speed, and high correlation with actual flushability or repulpability of the fibrous product, and utility in a process for manufacturing a fibrous sheet exhibiting controlled disintegration, such as a flushable or repulpable fibrous sheet.

The invention relates to a system of producing MFC (micro fibrillated cellulose) having a process device (30) of a pulper, a refiner or a screen configured to process MFC suspension to consistency of 0.5-5%. The system has a continuous pressing means (15; 25, 26) configured to dry the MFC suspension to a consistency of 6-60%. A method of producing MFC has at least one process stage (30) which processes a MFC suspension to a consistency of 0.5-5% by a process device (30). In the process stage the MFC suspension is pulped in a pulping stage in a pulper and/or refined in a refining stage by a refiner and/or screened in a screening stage by a screen. The MFC suspension having the consistency of 0.5-5% is dried in a drying stage of continuous pressing (15, 25, 26) by continuous a pressing device (15, 25, 26) to a consistency of 6-60%.