A gas circulation apparatus is applied to a pneumatic apparatus including a solenoid valve apparatus and a cylinder apparatus, and is connected in series between the solenoid valve apparatus and the cylinder apparatus. The gas circulation apparatus includes a valve core structure, a first circulation cavity, and a second circulation cavity. The valve core structure is configured to move in a first direction, so that compressed gas discharged from a first cylinder cavity of the cylinder apparatus and passing through the solenoid valve apparatus is collected and stored by the first circulation cavity, and a second cylinder cavity of the cylinder apparatus is supplied with compressed gas stored in the second circulation cavity together with the compressed gas supplied from the solenoid valve apparatus.

A pressure-booster output stabilizer includes: a first cylinder having therein a first chamber and a second chamber separated by a first piston; a second cylinder having therein a third chamber and a fourth chamber separated by a second piston; and a piston rod configured to couple the first piston and the second piston. The primary pressure of a pressure booster is supplied to the first chamber, the secondary pressure of the pressure booster is supplied to the fourth chamber, and the pressurized fluid is taken out from the fourth chamber.

The first piston of the first cylinder and the second piston of the second cylinder are connected so that the first piston and the second piston have the same displacement. The cross-section area of one side of the first piston is the smallest, and the cross-section area on the same side of the second piston is the third smallest. The two air chambers of the first cylinder and the two air chambers of the second cylinder are referred to as a first air chamber, a second air chamber, a third air chamber, and the fourth air in ascending order in the cross-section area. The control valve connects the air pressure source to the first air chamber, connects the second air chamber to the third air chamber, and opens the fourth air chamber to the atmosphere in the forward stroke.

An electric-powered fail-safe actuator for use with a valve, where the actuator stores potential energy for conversion to kinetic energy to close or open the valve to the fail-safe position.

A pressure fluid handling system includes a closed pressure fluid circuit. The pressure fluid circuit includes, connected in series, a compressor and a pressure sink and a primary pressure fluid route from the compressor to the pressure sink and a secondary pressure fluid route from the pressure sink to the compressor. The pressure fluid handling system further includes a pressure fluid accumulator connected to the pressure fluid circuit via a first pressure fluid accumulator conduit. The first pressure fluid accumulator conduit includes a pump configured to pump pressure fluid from the pressure fluid circuit to the pressure fluid accumulator to lower the pressure levels in the pressure fluid circuit, and in that the pressure fluid handling system includes a controllable component for returning the pressure fluid from the pressure fluid accumulator to the pressure fluid circuit to increase the pressure levels in the pressure fluid circuit.

An electric-powered fail-safe actuator for use with a valve, where the actuator stores potential energy for conversion to kinetic energy to close or open the valve to the fail-safe position.

In a cylinder drive device, a throttle valve and a second check valve are provided between a switch valve and a first cylinder chamber of a fluid pressure cylinder. The cylinder drive device has a flow channel unit which is interposed between a manifold and the switch valve, which allows communication between the throttle valve and the second check valve and switch valve, and which communicates with a plurality of holes in the manifold to allow a fluid to flow to the switch valve.

The present invention allows the number of components to be reduced and assembly work to be easily performed. A cylinder drive manifold device that constitutes a cylinder drive apparatus is provided with a block-shaped manifold in which a plurality of holes are formed for circulating a fluid used for driving a plurality of fluid pressure cylinders. The manifold is configured such that a plurality of switching valves for supplying a fluid alternately to a first cylinder chamber and a second cylinder chamber of each of the fluid pressure cylinders are attachable. A plurality of check valves and a plurality of throttle valves are incorporated into the plurality of holes of the manifold.

A drive device for driving a fluid pressure cylinder has an air supply source which supplies air, a switching valve which switches between the supply and discharge of the air to and from the fluid pressure cylinder, bypass piping which connects the head-side cylinder chamber and rod-side cylinder chamber of the fluid pressure cylinder, and a bypass switching valve which switches between the states of flow of air through the bypass piping. Air in the head-side cylinder chamber is supplied to the rod-side cylinder chamber through the bypass piping by setting the bypass switching valve to an open state in a return stroke of the fluid pressure cylinder.

A drive device for driving a fluid pressure cylinder has an air supply source which supplies air, a switching valve which switches between the supply and discharge of the air to and from the fluid pressure cylinder, bypass piping which connects the head-side cylinder chamber and rod-side cylinder chamber of the fluid pressure cylinder, and a bypass switching valve which switches between the states of flow of air through the bypass piping. Air in the head-side cylinder chamber is supplied to the rod-side cylinder chamber through the bypass piping by setting the bypass switching valve to an open state in a return stroke of the fluid pressure cylinder.