A system and process for conversion of heavy feedstocks in a slurry bed hydroprocessing reactor is provided in which hydrogen gas is dissolved in the liquid feedstock by mixing andor diffusion, the mixture is flashed to remove and recover any light components and hydrogen, leaving a hydrogen-enriched feedstock. The Block command prevents new traffic from being added to an output port of a device in a connection. The moment measuring means is attached to a force measuring means measuring the force directed in or parallel to the vertical axis.