structure of the same volume and material as the porous structure the throughput properties are increased by a plurality of drainage channels 150 250 it is preferred that the plurality of drainage channels 150 250 are frusta conical and having a sharply pointed tip towards the intersection between base structure 110 210 and support layer 120 220 e g the plurality of drainage channels 150 250 of the present embodiment has a nail form with the nail tip pointing towards the forming space 300 as is evident from fig1 all parts of the mould 100 200 are applied with the fine particles that forms the support layer 130 230 however all parts of that surface are not used to form a pulp object but there are peripheral surfaces 160 260 that will not be used to form a pulp object as a consequence these surfaces 160 260 preferably have a permeability that is substantially smaller than the moulding surfaces 130 230 in the preferred embodiment this is achieved by applying a thin impermeable layer 161 261 having appropriate properties e g any kind of paint having sufficient strength durability to maintain its impermeable function when used under operating conditions high heat some vibration pressure etc alternatively this impermeable layer 161 261 may be achieved by workshop machining techniques for instance by applying a high pressure upon these surfaces 160 260 to achieve a compacted surface layer 160 260 whereby the pores will be closed of course other methods of making these surfaces 160 260 impermeable can be used as long as the result.