Abstract: A reciprocating-piston compressor having at least two working cylinders arranged in series, along a cylinder axis is described. The compressor includes a piston in each of the cylinders, guided in an axially movable manner, and a common axially actuated piston rod of the pistons, extending through a passage opening in a partition between the at least two working cylinders. The at least two working cylinders are sealed off with respect to one another in a region of the common axially actuated piston rod, exclusively by a non-contact seal. The axial seal has an axial gap seal formed between a radially outer circumferential surface of the common axially actuated piston rod and a radially inner circumferential surface of the passage opening.

Abstract: A reciprocating-piston compressor having at least two working cylinders arranged in series, along a cylinder axis is described. The compressor includes a piston in each of the cylinders, guided in an axially movable manner, and a common axially actuated piston rod of the pistons, extending through a passage opening in a partition between the at least two working cylinders. The at least two working cylinders are sealed off with respect to one another in a region of the common axially actuated piston rod, exclusively by a non-contact seal. The axial seal has an axial gap seal formed between a radially outer circumferential surface of the common axially actuated piston rod and a radially inner circumferential surface of the passage opening.

Abstract: An electrode for a lead-acid storage cell, electrode containing an active material (8), an active material support and at least one electric conductor which includes a core (10) made of a metal whose electric conductivity is higher than that of lead. Said core is coated with a protective layer (11) made of a substance chosen from the group comprising titanium, tungsten, tantalum, niobium, zirconium and alloys thereof.