An adsorption separation device is used with a cylinder, wherein the cylinder comprises a cylinder body, a first piston, and a second piston. The first piston and the second piston are arranged inside the cylinder body, and the first piston and the second piston are be spaced from each other. The cylinder further comprises a first shaft and a second shaft where the first shaft extends into the cylinder body and is connected with the first piston, and the second shaft is slidably sleeved in the first shaft and connected with the second piston. The adsorption separation device includes the cylinder. The cylinder and the adsorption separation device are actually two or more cylinders sharing the same cylinder body and controlling two or more pistons and shafts respectively. The control directions and strokes of the pistons are independent relative to each other and do not affect each other.

A two-stage servo valve comprising a first drive stage and a second fluid transfer stage. The fluid transfer stage includes a housing having a plurality of ports and a spool axially moveable within an axial cavity defined within the housing to control flow of fluid between the plurality of ports according to the axial position of the spool, wherein the drive stage is configured to cause axial movement of the spool. The housing has three ports, a first port being a supply port fluidly connected to a second port, being a control port, via a supply channel (sc) and a first control channel (cc1) via the spool cavity, and a third port being a return port fluidly connected to the control port via a return channel (rc) and a second control channel (cc2) via the spool cavity.

The disclosure relates to a hydraulic system having a hydraulically actuable working cylinder which has a cylinder housing with a piston-rod unit that is guided in longitudinal movement therein, is actuable in opposite directions and subdivides the cylinder housing into a piston chamber and a rod chamber, and having two proportional pressure control valves, of which one is assigned to the piston chamber and the other is assigned to the rod chamber, wherein a connecting line is connected in a fluid-conducting connection between the rod chamber and the proportional pressure control valve assigned to the rod chamber, said connecting line being guided to an input side of the proportional pressure control valve for the piston chamber such that, when the piston-rod unit is extended, the fluid displaced from the rod chamber passes into the piston chamber of the cylinder housing.