7 Mechanical transport and conveyor devices for feeding solids in biogas fermenters, namely, pneumatic and hydraulic transporters, conveyors, machines for conveying solids; mechanical transport and conveyor devices for use in sliding floor bunkers and silos, namely, pneumatic and hydraulic transporters, conveyors, machines for conveying solids; mechanical transport and conveyor devices for biogas installations and block-type cogeneration installations, namely, pneumatic and hydraulic transporters, conveyors, machines for conveying solids; agitators for circulating liquid and semi-liquid media for biogas installations and block-type cogeneration installations; and crushing and pressing machines, namely, waste crushing machines, industrial machine presses for biogas installations and block-type cogeneration installations; Installations for separating solid and liquid substances, namely, centrifuges, cyclone separators; valves for controlling excess pressure and negative pressure in gas storage units and fermentation vessels, namely, pump control valves, valves for pumps, servo-valves; installations for process heat recovery in biogas installations, namely, heat exchangers being parts of machines for recovering process heat; installations for extracting nutrients and fertilizers, namely, centrifuges and extracting machines; valves for controlling excess pressure and negative pressure in gas storage units and fermentation vessels, namely, valves being parts of machines