Process fluid flow device with variable orifice
AssigneeRosemount Inc.
InventorRobert C. Hedtke
Life of this patent
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Abstract
A process device providing total fluid flow control is provided. The device includes a closure mechanism disposed in a flow conduit. The closure mechanism, which is preferably an iris-type diaphragm, provides a variable internal diameter. The device includes a differential pressure sensor for sensing the differential pressure on opposite sides of the diaphragm. A controller receives an indication of differential pressure and generates a control signal to an actuator that actuates the closure mechanism. The closure mechanism, differential pressure sensor and controller create a closed-loop flow controller in a single process device.
Claims28
A process fluid flow control device comprising:
- a closure mechanism disposed in a flow conduit, the closure mechanism providing a selective degree of fluid flow obstruction through the flow conduit;
- an actuator coupled to the closure mechanism to control the selective degree of fluid flow obstruction based upon a control signal;
- a differential pressure sensor disposed to sense differential process fluid pressure across the fluid flow obstruction;
- measurement circuitry coupled to the differential pressure sensor, the measurement circuitry configured to obtain an indication of differential pressure from the differential pressure sensor;
- a controller coupled to the measurement circuitry and the actuator, the controller executing a control algorithm to generate the control signal based on the indication of differential pressure;
- and
- a loop communication module coupled to a plurality of loop terminals and the controller, the loop communication module being adapted to communicate in accordance with a process industry standard protocol.
A method of controlling process fluid flow using a single process device, the method comprising:
- measuring a differential pressure of process fluid flowing through an iris-diaphragm;
- generating a control output based upon a selected fluid flow setpoint and the measured differential pressure;
- and
- adjusting the iris-diaphragm based upon the control output.
A method of measuring process fluid flow, the method comprising:
- directing the process fluid flow through a variable orifice;
- measuring differential pressure of the process fluid across the variable orifice;
- an&
- adjusting the variable orifice if the measured fluid flow meets a selected threshold.
A method of verifying operation of a process fluid flow device having a variable orifice and a differential pressure sensor disposed to sense differential pressure across the variable orifice, the method comprising:
- measuring a first differential pressure across the variable orifice when the variable orifice is set to a first closure level;
- setting the variable orifice to a second closure level different than the first closure level;
- measuring a second differential pressure across the variable orifice set to the second closure level;
- and
- comparing the first differential pressure with the second differential pressure to generate a verification output.
Dependencies are inferred from the claim text.