A gas valve assembly with integrated pressure regulator is provided. The gas valve assembly includes a pressure regulator and a gas valve module. The pressure regulator and gas valve modules each include cast housing bodies. The cast housing bodies have cast in mounting holes and assembly features that allow for the assembly of the gas valve assembly without secondary machining operations.

An electro-pneumatic actuator, such as a positioner or an I/P transducer array, for a field device of a processing plant, such as a brewery, a petrochemical plant or the like, can include a pneumatically operated display configured to visually and/or acoustically display at least one field device-specific operating information. The information can include a drive or valve position, or a regulating variable. The electro-pneumatic actuator can be configured to output at least one pneumatic drive actuating signal to a pneumatic drive so as to set a final controlling device, such as a control valve, of the field device. The electro-pneumatic actuator can be configured to output at least one pneumatic display actuating signal to the pneumatically operated display, which can differ from the pneumatic drive actuating signal.

A valve positioner that can maintain operation of the control valve despite failures in one or more components. The valve positioner may reduce downtime by allowing in-situ repair to occur on the valve positioner. The valve positioner may incorporate a by-pass component, which can utilize control input signals (e.g., a 4-20 mA signal) to energize one or more components (e.g., a current-to-pressure converter) to cause the control valve to modulate fluid flow without the digital microprocessor and/or related components.

A first table defines the relationship between the sliding resistance index k of a packing gland and the ambient temperature for each type of the packing gland is provided. A second table defines control parameters corresponding to hysteresis levels for each size of the setting/operating device is provided. By repeating, at regular intervals, the acquisition of the sliding resistance index k at present corresponding to the ambient temperature at present and the type of a packing gland from the first table and the selection of the control parameter corresponding to the size of the setting/operating device and the hysteresis level obtained from the sliding resistance index k at present from the second table, the valve opening of the regulating valve is controlled using the selected control parameter.

A hydraulic drive system (1) including a meter-in compensator (37) and a bleed-off compensator (42) comprises a plurality of sensors (64 to 68), a controller (62), and an outlet pressure switching valve (61). The controller (62) determines whether or not the state of a wheel loader (2) which is detected based on the signals output from the sensors (64 to 68) meets a predetermined steering limiting condition. When the controller (62) determines that the state of the wheel loader (2) meets the steering limiting condition, it outputs a command signal to the outlet pressure switching valve (61). The outlet pressure switching valve (61) reduces the flow rate of the hydraulic oil flowing to steering cylinders (18L, 18R), in response to the command signal in such a manner that the flow rate becomes lower than that corresponding to the operation amount of a handle of a steering device (35).

A hydraulic drive system (1) including a meter-in compensator (37) and a bleed-off compensator (42) comprises a plurality of sensors (64 to 68), a controller (62), and an outlet pressure switching valve (61). The controller (62) determines whether or not the state of a wheel loader (2) which is detected based on the signals output from the sensors (64 to 68) meets a predetermined steering limiting condition. When the controller (62) determines that the state of the wheel loader (2) meets the steering limiting condition, it outputs a command signal to the outlet pressure switching valve (61). The outlet pressure switching valve (61) reduces the flow rate of the hydraulic oil flowing to steering cylinders (18L, 18R), in response to the command signal in such a manner that the flow rate becomes lower than that corresponding to the operation amount of a handle of a steering device (35).

An electro-pneumatic controller adapted to use a non-inert fluid as a control fluid includes a base portion and a cap portion removeably secured to the base portion. A non-intrinsically-safe process may be disposed within an interior of the cap portion. A plurality of passageways may be disposed through the base portion. The electro-pneumatic controller may also include a flameproof barrier assembly which may include a plurality of flameproof joints each disposed within desired portion of the plurality of passageways. The plurality of flameproof joints cooperate to at least partially define a first zone, the flameproof joints adapted to prevent or to limit the spread of an open fire or explosion that might occur due to the ignition of the non-inert control fluid.

A transducer for a connection to a fluid pressure source having a mechanism for setting a pneumatic output by way of an electrical input signal. The transducer provides a lower housing assembly and an upper housing assembly. The lower housing assembly comprises lower housing configured to receive a supply nozzle. The supply nozzle fluidly communicates with a supply port and intermittently fluidly communicates with an output port of the lower housing through an internal fluid passageway. The upper housing assembly comprises an upper housing configured to receive a coil and an armature such that the upper housing, coil and armature define a latching electromagnetic circuit that provides alternating contact of the armature with the supply nozzle of the lower housing assembly.

A piezoelectric actuator for a miniature fluid transportation device is provided and includes a piezoelectric actuating plate and a piezoelectric element. The piezoelectric actuating plate includes a suspension plate, an outer frame, and brackets. The suspension plate has a first thickness. The outer frame is arranged around the suspension plate and has a third thickness. Each of the brackets is connected between the suspension plate and the outer frame and has a fourth thickness. The third thickness is larger than the first thickness, and the first thickness is larger than the fourth thickness. The suspension plate, the outer frame and the brackets are constructed to form different stepped structures to minimize the thickness of the brackets, enhance the elasticity of the brackets. Thus, displacement of the suspension plate in the vertical direction is enhanced and the transportation efficiency of the miniature fluid transportation device is intensified.

A pneumatic valve arrangement for a pneumatically operated field device, such as a control device, of a processing plant, such as a chemical plant, a foodstuff processing plant, a power plant or the like is disclosed. The valve arrangement may include an air supply conduit for receiving pressurized air from a source of pressurized air, a control air conduit for aerating and venting a pneumatic actor of the field device, and a venting conduit for discharging pressurized air to a pressure sink, such as the atmosphere; a venting valve for opening and/or closing the venting conduit and an aerating valve for opening and/or closing the air supply conduit; and a pivotable carrier lever for common actuation of the aerating valve and of the venting valve, wherein the carrier lever holds the venting valve in its closed position while it opens the aerating valve from its closed position.