level which is established by the diffuser pump device is in the interval 6 u2013 12 bar but is at least 2 bar higher than the first pressure level and the third pressure level which is established by the digester pump is in the interval 12 u2013 25 bar the system becomes self regulating in the event of any operational disturbances in the flow of washing liquid and if the pumps are appropriate a countercurrent flow of washing liquid through the system is essentially maintained application_number US 47422303 A description fig1 shows a system according to the invention for supplying washing liquid to a continuous digester 1 for cellulose pulp and a subsequent diffuser washing device 2 a 2 b in which washing liquid 12 a 12 b for the diffuser washing device is drawn from a storage tank 4 and in which washing liquid 17 is conducted to the bottom of the digester in order to obtain a dilution and or a displacement washing at the bottom of the digester the cellulose pulp which is dissolved in the digester is fed out in the flow 20 and a y coupling arrangement is preferably used to ensure the establishment of two constituent flows 20 a 20 b to two diffusers which consequently operate in parallel the central branch in the y coupling provides an alternative auxiliary feeding route for the flow 20 a or else the flow 2 o b after the diffusers washed pulp 21 a 21 b is withdrawn from each respective diffuser and combined in the flow 22 for subsequent conduction to a storage tank 3 for the cooked and washed pulp the diffuser is a conventional pressure diffuser which maintains the pressure in.