communicating chambers 23 are located above liquid level 6 of fiber stock suspension 2 in tank 3 please refer to fig1 and 2 regarding possible arrangement of outlet opening 17 including overflow pipe 19 for separated excess fiber stock suspension 2 2 overflow 25 in the form of overflow pipe 24 having overflow height h u00fc1 and overflow length l u00fc1 is located prior to outlet opening 15 for directing the flow of the gas free fiber stock suspension 2 1 concerning the arrangement of overflow pipe 24 we refer you to the details in fig1 pertaining to overflow pipe 19 and overflow 20 for the flow of separated excess fiber stock suspension 2 2 additionally referring to fig3 there is shown device 1 designed for deaerating of fiber stock suspension 2 device 1 includes horizontal cylindrical tank 3 with a tank axis 3 a into which fiber stock suspension 2 that is to be supplied to the paper or cardboard machine is fed in the form of a thin mixture through at least one distributer pipe 4 from which a multitude of successive jet tubes 5 originate for feeding fiber stock suspension 2 into tank 3 regarding additional design characteristics please refer to tank 3 illustrated in fig1 outlet opening 26 for the flow of gas free fiber stock suspension 2 1 is located in floor 27 of tank 3 a vacuum.