Abstract: Fault diagnostics utilize an embedded tracking digital twin of a valve assembly physical part in a microprocessor system of the valve positioner. The digital twin has simulation model parameters including a fault-related simulation model parameter. The digital twin receives a control signal representing a real control of the at least part of the valve assembly, and generates simulated measurements relating to the simulated control result. The digital twin compare the simulated measurements with real measurements that relate to the real control result, to track an error between the results of simulated operation and the real operation of the valve assembly to adjust the fault-related simulation model parameter in a sense that the error is decreased. The fault-related simulation model parameter relates to a specific physical fault in the physical part of the valve assembly, and it is detectable and identifiable based on the simulation model parameter adjusted value.

Abstract: A valve and a bearing surface for a valve and a manufacturing method of the same including a valve body with a main channel extending between a fluid inlet and a fluid outlet, and a closing member provided in the main channel. The valve further includes a shaft connected to the closing member for moving the closing member between an open and a closed position. Moreover, the valve includes at least one bearing surface between the valve body and the closing member or the valve body and the shaft, the bearing surface further including a plurality of cavities filled with solid lubricant.

Abstract: A valve including: a flow channel and a closure member. A first sealing surface is provided along walls of the flow channel and a second sealing surface is provided along outer edges of a sealing section of the closure member. A rotation axis is offset from the sealing section by a first predetermined distance and from a centerline of the closure member by a second predetermined distance. To ensure smooth operation of the closure member at least one of the first and second sealing surfaces has a non-conical shape that is at least in one area asymmetric with respect to the center axis of the closure member.

Abstract: A controller for controlling a pneumatic or hydraulic actuator of a process device includes a position feedback signal input for receiving a measured position signal representing a position of the actuator or the process device, an actuator pressure output, and a pressure sensor for measuring the actuator pressure. The controller is configured to operate in a measured position feedback mode and a simulated position feedback mode. In the measured position feedback mode the actuator is controlled dependent on a setpoint position and the measured position, and in the simulated position feedback mode the actuator is controller based on the setpoint position and a simulated position of the actuator or the process device. The simulated position is derived from the measured actuator pressure by a simulation model.

Abstract: A valve sealing arrangement, including a valve body, and a closing member including a closing member contact surface, and a seat, having a center axis, and provided with a sealing portion with a first sealing surface for making contact with the closing member and a back sealing portion with a second sealing surface for making contact with a surface of the valve body. The seat also includes a bellows between the first sealing surface and the second sealing surface wherein the bellows including bellow members wherein adjacent bellow walls form either inwardly open fold or outwardly open fold and wherein one or more of the bellow members extends in a direction that is oblique to the center axis of the seat.

Abstract: A valve and a bearing surface for a valve and a manufacturing method of the same including a valve body with a main channel extending between a fluid inlet and a fluid outlet, and a closing member provided in the main channel. The valve further includes a shaft connected to the closing member for moving the closing member between an open and a closed position. Moreover, the valve includes at least one bearing surface between the valve body and the closing member or the valve body and the shaft, the bearing surface further including a plurality of cavities filled with solid lubricant. An advantage of the claimed valve is that the lubricant is maintained longer on the bearing surfaces and thus lubrication periods and valve lifetime are increased.

Abstract: A valve sealing arrangement, including a valve body, and a closing member including a closing member contact surface, and a seat, having a center axis, and provided with a sealing portion with a first sealing surface for making contact with the closing member and a back sealing portion with a second sealing surface for making contact with a surface of the valve body. The seat also includes a bellows between the first sealing surface and the second sealing surface wherein the bellows including bellow members wherein adjacent bellow walls form either inwardly open fold or outwardly open fold and wherein one or more of the bellow members extends in a direction that is oblique to the center axis of the seat.

Abstract: A fluid valve assembly having a central bore and a stem axially-movable within the central bore and actuated by an axial pilot force and an axial counter force. An inner supply pressure chamber is provided to retain a stabilized supply pressure providing the axial counter force affecting on the stem. A seal member is arranged coaxially with the stem between the inner supply pressure chamber and an outer supply pressure chamber which is connected to a supply pressure input line. A metering edge is arranged coaxially with the stem to control fluid flow from the outer supply pressure chamber to an actuator chamber. Means are provided to stabilize the supply pressure in the inner chamber against sudden pressure drops in the outer supply pressure chamber.

Abstract: A valve including: a flow channel and a closure member. A first sealing surface is provided along walls of the flow channel and a second sealing surface is provided along outer edges of a sealing section of the closure member. A rotation axis is offset from the sealing section by a first predetermined distance and from a centerline of the closure member by a second predetermined distance. To ensure smooth operation of the closure member at least one of the first and second sealing surfaces has a non-conical shape that is at least in one area asymmetric with respect to the center axis of the closure member.