Abstract: A membrane dryer apparatus for moist air includes a housing (1) that contains a tubular fabric strand bundle (7) of tubular fabric strands (8) made of selective absorption material through which air to be dried flows, water vapor diffusing through the fabric and collecting on its outside. A portion of the dried compressed output air is channeled off near the discharge (12) of the membrane dryer and passed through a scavenging air duct (14) having a throttle (16) and passed around the outside of the fabric strand bundle to scavenge moisture and remove it through discharge openings (17, 18) to the outside air. To limit consumption of scavenging air, an independent shut-off valve (19), working as an airflow sensor, is installed in the output air duct (13), and this shut-off valve (19) opens only when output air is actually extracted by a user.

Abstract: A fluid cylinder control method for monitoring the position or controlling the movements of a piston which is slidably guided in a cylinder tube and is acted upon on at least one side by a pressure medium, in particular, maintaining the piston in a predetermined position against the action of eventual disturbance forces. This is attained in that the force which is transmitted between the piston and the cylinder by way of the parts which are slidingly guided on each other, and in particular the friction force acting by way of the seal gaskets of the piston and/or of the rod, is measured and the loading of the piston by a pressure medium is varied in the sense of reducing the measured force.

Abstract: In apparatus for controlling a lubricating device which is actuated by pulses of compressed air, the apparatus including a drive piston disposed in a cylinder to undergo reciprocating movement under the action of each such pulse and a control valve disposed between the source of such pulses and the lubricating device, the control valve is periodically opened to permit one such compressed air pulse to be delivered to the lubricating device only after a predetermined number of compressed air pulses have been produced, by means of a stepping mechanism which includes a reciprocating pump connected to be driven by the drive piston to supply, in response to each cycle of movement of the drive piston, a predetermined quantity of liquid, an actuating cylinder containing an actuating piston and arranged to receive each such quantity of liquid to move the piston in a unidirectional, step-wise manner so that the actuating piston advances through the cylinder in discrete steps as a series of quantities of liquid are supp