A piston member that includes a piston rod provided with a piston serves for reciprocating inside a cylinder barrel, the piston dividing the cylinder barrel chamber into a proximal cylinder barrel chamber having a proximal capped end opposite the piston and a distal cylinder barrel chamber having a distal cylinder barrel end opposite the piston. The piston member has at least one sealing ring or seat arranged inside the distal cylinder barrel chamber at the distal cylinder barrel end. Preferably three consecutive piston members are arranged to operate in a series in an apparatus for transporting coal powder to a gasifier. The movement of the pistons inside the cylinder barrels is controlled in relation to each other to transport apportioned batches of coal powder to a high pressure reactor.