Accuracy of control valves using a short-stroke position converter
AssigneeDresser, Inc.
InventorsJustin Walter Betley, John Gregory Canning
Life of this patent
Estimating the term…
Abstract
A position transfer device is configured for use on a control valve. These configurations may convert a linear position of a closure member on the control valve to an angular position of magnets. A sensor in proximity to the magnets can generate a signal in response to the angular position. A valve positioner or controller can process the signal to identify the position of the closure member relative to a seat. In one implementation, the position transfer device includes a shaft that clamps onto a pin. This arrangement causes the pin to translate radially about an axis that is perpendicular to the shaft. The magnets move in response to the pin.
Claims17
A valve assembly, comprising:
- a pneumatic actuator;
- a valve stem coupled with the pneumatic actuator;
- a shaft coupled with the valve stem and configured to move concomitantly with the valve stem;
- a rotatable mechanism coupled with the shaft, the rotatable mechanism comprising a pin engaged with the shaft and magnets that have an angular position that corresponds with a linear position of the valve stem;
- and
- a sleeve with a through-hole to receive the shaft, wherein the pin extends in between the shaft and the sleeve.
A valve assembly, comprising:
- a pneumatic actuator;
- a valve stem coupled with the pneumatic actuator;
- a shaft coupled with the valve stem and configured to move concomitantly with the valve stem;
- and
- a rotatable mechanism coupled with the shaft, the rotatable mechanism comprising a pin engaged with the shaft and magnets that have an angular position that corresponds with a linear position of the valve stem;
- a sleeve with a through-hole to receive the shaft;
- and
- a biasing unit that generates a pre-load to clamp the pin between the shaft and the sleeve.
A valve assembly, comprising:
- a pneumatic actuator;
- a valve stem coupled with the pneumatic actuator;
- a shaft coupled with the valve stem and configured to move concomitantly with the valve stem;
- and
- a rotatable mechanism coupled with the shaft, the rotatable mechanism comprising a pin engaged with the shaft and magnets that have an angular position that corresponds with a linear position of the valve stem;
- a sleeve with a through-hole to receive the shaft;
- spring washers disposed on an end of the shaft;
- and
- a nut threaded onto the end of the shaft in position to compress the spring washers,
- wherein the pin extends between the shaft and the sleeve.
A valve assembly, comprising:
- a pneumatic actuator;
- a valve stem coupled with the pneumatic actuator;
- a shaft coupled with the valve stem and configured to move concomitantly with the valve stem;
- and
- a rotatable mechanism coupled with the shaft, the rotatable mechanism comprising a pin engaged with the shaft and magnets that have an angular position that corresponds with a linear position of the valve stem,
- wherein the shaft comprises a first part and a second part with a reduced diameter section that extends into the first part and forms a shoulder so as to receive the pin between the shoulder and an end of the first part.
A control valve, comprising:
- a valve with a closure member, a seat, a valve stem, and an actuator;
- a measurement system configured to measure a position of the closure member, the measurement system comprising:
- a sensor;
- a shaft coupled with the closure member, the shaft having two, separate parts with adjacent ends, the shaft moveable along a first axis to a position that corresponds with a location for the closure member relative to the seat;
- a pin extending perpendicular to the first axis and having a first end extending into a gap formed between the adjacent ends of the two, separate parts of the shaft;
- and
- a pair of magnets coupled with the pin and in proximity to the sensor, the pair of magnets rotatable about a second axis that is perpendicular to the first axis.
Dependencies are inferred from the claim text.