Aspects of the present disclosure relate to fail open or fail close actuator assemblies and related methods for valve systems. In one implementation, an actuator assembly for valves includes an outer housing that includes an inner surface at least partially defining an internal volume. The actuator assembly includes one or more first fluid openings formed in the outer housing, one or more second fluid openings formed in the outer housing, and one or more ambient openings formed in the outer housing. The actuator assembly includes a valve stem disposed at least partially in the internal volume, and a first piston disposed in the internal volume and coupled to the valve stem. The actuator assembly includes a second piston disposed in the internal volume and disposed about the valve stem.

A multi-stage shift pack assembly and method includes a frame assembly, a tool mounting movable relative to the frame assembly, and a removable cylinder shift pack secured to the frame assembly and having at least two cylinders that are independently actuatable for moving the tool mounting relative to the frame assembly a desired amount. The tool mounting is moved relative to the frame assembly by independently actuating cylinders of the removable cylinder shift pack.

In an exemplary method of monitoring performance of a fluid driven actuator for a valve, pressurized fluid is supplied through an actuator supply line to an inlet port of the actuator during a first time period to operate the actuator. Changes corresponding to a fluid flow condition in the actuator supply line are measured during the first time period, and the measured changes are analyzed to identify a non-compliant condition in at least one of the valve and the actuator. An output communicating the identified non-compliant condition is then generated.

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 servo-control. The servo-control comprises at least one body as well as a power shaft and a control piston arranged in each body, the at least one body and the power shaft respectively forming two power members. One of the power members bears at least on end-stop member and the power member without an end-stop member bears a passivation actuator. The passivation actuator comprises a passivation shaft which bears an end-stop and a passivation piston, the passivation piston being arranged to be mobile in longitudinal translation in an enclosure, an elastic system being arranged between the passivation piston and the enclosure.

A pneumatic drive for a medical robot includes a manifold having cylinders extending in a first direction, and respective rods corresponding to the cylinders, the rods extending on one side of the cylinders in the first direction. The manifold includes air supply ports that feed the cylinders with air for moving the respective rods forward and backward. The air supply ports are provided on another side of the manifold in the first direction.

A recirculating gradient power system includes a motion carrier, a counterweight, power cylinders and a control module. A central vertical axis of the motion carrier has a rotating shaft pivotally connected with the counterweight. The power cylinders connected with a pressure source are evenly arranged at diagonal corners around the periphery of the central vertical axis. The control module connected with the power cylinders controls operation of the power cylinders which are set in advance when the counterweight is rotationally displaced to a predetermined stroke. The pressure source sequentially provides compressed gas fluid to the power cylinders to make the motion carrier continuously change its tilt orientation and tilt angle, thus forming a virtual continuous gradient. The counterweight is rotationally displaced from a high point of the motion carrier toward a lower point of the motion carrier about the rotating shaft by gravity, and the rotating shaft rotates continuously.

The invention relates to agate valve hydraulic actuator, said actuator comprising a cup shaped sleeve (9) which is operably coupled to an opening or closing element (5) of the gate valve (2), the actuator further comprising a movable primary piston (13) arranged within a primary cylinder (12) arranged at the inside of the cup-shaped sleeve (9), said primary piston (13) being con figured to move the sleeve (9) and hence said opening and closing element (5) towards an open or closed position of the gate valve (2) by a force applied to the primary piston (13). The hydraulic actuator is distinctive in that it further comprising a movable secondary piston (11) arranged within a secondary cylinder (10) arranged at the inside of the cup shaped sleeve (9), said secondary piston (11) being configured to move the sleeve (9) to the same position of the gate valve (2) as the primary piston by a force applied to the secondary piston in case of failure of the primary piston (13), said primary piston (13) and secondary piston (11) are independently operable of each other.

A lifting device for lifting a table includes two legs, each of the legs includes a pneumatic assembly and an inner rod, the pneumatic assemblies are disposed in the legs, and the inner rods are inserted in the legs and connected to the pneumatic assemblies, so that the pneumatic assemblies drive the inner rods to move up and down. A synchronization mechanism is disposed between the two legs, and has two ends connected to the inner rods by two connecting assemblies, so that the inner rods are driven by the synchronization mechanism to lift or lower the tabletop in a synchronous manner, the synchronization mechanism includes: a cable control unit and a clutch unit controlled by the cable control unit, the cable control unit includes a control handle and a cable which is disposed at the bottom of the tabletop.

A communication path that communicates with a first main pressure chamber is provided in a main piston and a piston rod. A check valve, which opens by being pressed by a booster piston and allows the communication path to communicate with a first sub-pressure chamber when the piston rod reaches a booster start position before a forward stroke end, is disposed in an end portion of the communication path. A plurality of steel balls are disposed in a coupling-member containing chamber formed in the booster piston. An engagement surface and an engagement groove, which engage with the steel balls when the booster piston moves forward due to an action of a pressure fluid supplied to the first sub-pressure chamber 11a through the communication path, are formed in the coupling-member containing chamber and an outer peripheral surface of the piston rod.