A pressure booster constituting a cylinder apparatus is provided with a first piston and a second piston that are coupled to each other by a rod. A connection member provided to the second piston is configured so as to be displaceable from a connection position to a blocking position as a result of the connection member making contact with a cylinder body when the second piston is displaced in a direction where a boosting chamber contracts, and so as to be displaceable from the blocking position to the connection position as a result of the connection member making contact with the cylinder body when the second piston is displaced in a direction where the boosting chamber expands.

A system initiates a start of at least one of a flow of a fluid into one section of an actuator or an exhaust of the fluid from another section of the actuator to move a piston from a current to a destination position. The system also initiates a stop of at least one of the flow of the fluid into the one section of the actuator or the exhaust of the fluid from the another section of the actuator no later than when the current position is at the destination position and before at least one of: a pressure of the fluid within the one section is the same as the pressure of the fluid in a fluid line providing the fluid; or pressure of the fluid within the another section is the same as the pressure of the fluid at an end of an exhaust line exhausting the fluid.

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 from a normal position to an actuated position. Pressure changes corresponding to a fluid flow condition in the actuator supply line are measured during the first time period, with the measured pressure changes defining a valve cycle pressure profile including a first inflection point corresponding to movement of the actuator from the normal position to the actuated position. The valve cycle pressure profile is 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.

A selection system for hydraulic circuits has a cylinder selection processing unit; a database in which information pertaining to a combination of a plurality of apparatuses is registered in advance; combination selection processing units for reading information pertaining to the combination of the plurality of apparatuses in order of size from the database, and selecting an apparatus; and re-selection processing units for re-selecting an apparatus that is the next size up when a stroke time obtained by a simulation including some of the apparatuses selected by the combination selection unit exceeds an upper-limit stroke time, or when pressure after a return process is less than or equal to minimum working pressure.

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.

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.

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.

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.

A first fluid circuit is a fluid circuit of an air cylinder provided with an air cylinder with a first air chamber and a second air chamber that are defined by a piston; a switching valve that is switched between the drive step and return step of the piston; a first flow channel between the first air chamber and the switching valve; and a second flow channel between the second air chamber and the switching valve. Two speed control valves are provided in series in the second flow channel.