swelling of the wood chips a uniform discharge of the bulk material is thus achieved for the conditioning of the wood chips which can preferably be carried out at low pressure and at a constant temperature of 92 u00b0 c but also under a high pressure of for example 12 bar and at approximately 190 u00b0 c there are steam nozzles 15 which are arranged and distributed at various locations in the silo 2 so as to ensure a substantially uniform introduction of steam in the present exemplary embodiment the steam nozzles 15 are provided both on the side walls of the silo 2 in different planes and at different distances from one another and on the cross member 14 and especially also on or under the silo bottom 3 on and the trough 6 of the discharge screw conveyor 5 at the same time the steam nozzles 15 are arranged in such a way that they are largely shielded against the bulk material in order to prevent clogging of the nozzles for this purpose the steam nozzles are preferably arranged on the silo 2 in the region of the spaces 16 which are located under the fittings 11 to 14 or which are jointly limited by their oblique guide surfaces 10 the lower steam nozzles above all are protected by sieve shaped plates with conical orifices fig5 it can be seen from the exemplary embodiment of fig5 that the steam nozzles 15 can have conical outflow holes 17 which taper conically in the direction of the steam flow arrow it can be beneficial at the same time to design the steam.