Abstract: In a two-stroke internal combustion engine with an engine block including a crankcase and a cylinder housing receiving pistons which are connected to a crankshaft by crosshead rods with crossheads guided for linear movement with the piston and a connecting rod extending between the crosshead and the crankshaft, wherein the cylinders have walls with inlet and outlet slits disposed above the bottom dead-center position of the piston and providing for communication between the cylinder and inlet and outlet channel structures formed in the cylinder housing around the pistons, the engine block consists of a cylinder housing and a crankcase joined along a dividing plane extending across the engine block below the lowest piston ring when the piston is in its bottom position and the cylinder housing includes channel structures which are open toward the dividing plane and have walls extending inwardly and have inner surfaces in engagement with the piston for guiding said piston and to form, with the piston skirt, the

Abstract: A system for optimal pressure control in a multistage evaporation unit comprising two or more series connected evaporation stages with at least one of the stages preceded by a heat source, where the fresh or feed solution is passed through heat exchangers in which it is heated by means of the vapors from the subsequent evaporation stages, and where a heat exchanger adapted to permit free flow of the vapor condensate through the heat exchanger inner portion or tube portion is arranged in the line through which the vapor leaves the higher-pressure evaporation stage.