Patent ID: 6725167
Filing Date: 2004-04-20
Classification: G01F,G05D,Y10T

Abstract:
A flow measurement module adapted to operate in conjunction with an existing control valve assembly having an associated control system the control valve assembly including a valve assembly including a throttling element moveable within the flow passage and an intelligent positioner adapted to sense the approximate position of the throttling element within the flow passage and responsively generate a representative position feedback signal, the control system being communicatively coupled to the intelligent positioner to deliver a position setpoint signal to the intelligent positioner and receive the position feedback signal from the intelligent positioner, the flow measurement module comprising:a first communication port adapted to receive an upstream pressure signal representative of a sensed pressure upstream of the throttling element; a second communication port adapted to receive a downstream pressure signal representative of a sensed pressure downstream of the throttling element; a third communication port adapted to receive the position feedback signal representative of the approximate position of the throttling element within the flow passage without disrupting the flow of fluid through the flow passage; and a controller communicatively coupled to the first, second and third communication ports, the controller being adapted to operate in accordance with a computer program embodied on a computer readable medium, the computer program comprising: a first routine that directs the controller to determine a valve sizing coefficient based on the received position feedback signal; and a second routine that directs the controller to determine the flow rate of the fluid flowing through the flow passage based on the determined valve sizing coefficient, the received upstream pressure signal and the received downstream pressure signal.