Fluid flow impedance monitoring system

A system for monitoring impedance to flow in a fluid delivery system in which a flow control device acts on a fluid conduit to control the flow of fluid through the conduit, the system comprising:

• a pressure sensor coupled to the conduit for providing pressure signals in response to the pressure sensed in the conduit;
• a memory that provides a flow waveform corresponding to the flow of fluid in the conduit;
• and
• a processor comprising a model of the relationship between flow and pressure that receives the pressure signals and the flow waveform, processes the pressure signals with the flow waveform, and determines the impedance to flow based on said processing wherein the processor applies a parameter estimation technique in accordance with the model to determine the impedance.

A system for monitoring impedance to flow in a fluid delivery system in which a flow control device acts on a fluid conduit in response to an operator selected flow rate to control the movement of fluid through the conduit, the system comprising:

• a pressure sensor coupled to the conduit for providing pressure signals in response to the pressure sensed in the conduit;
• a flow table memory in which a flow waveform is stored;
• a processor that;
• should be:
• analyzes the selected flow rate and determines if the flow rate is above or below a threshold;
• if the flow rate is above the threshold, the processor controls the flow control device to cause a plurality of different flow rates to exist in the conduit, receives the pressure signals resulting from each flow rate, and determines the impedance by processing changes in pressure and changes in flow together;
• and
• if the flow rate is below the threshold, the processor receives the pressure signals, retrieves from the flow table memory a flow waveform corresponding to the selected flow rate, and processes the pressure signals with the flow waveform to determine the impedance to flow.

A system for monitoring impedance to flow in a fluid delivery system in which a flow control device acts on a fluid conduit to control the flow of fluid through the conduit, the system comprising:

• a pressure sensor coupled to the conduit for providing pressure signals in response to the pressure sensed in the conduit;
• a memory that provides a flow waveform corresponding to the flow of fluid in the conduit;
• and
• a processor that:
• controls the flow control device to cause flow in accordance with a pattern of flow variation about a selected flow rate, wherein the pattern of flow variation comprises a pseudo-random binary code;
• receives the pressure signals and the flow waveform;
• decodes the received pressure signals based on the pattern of flow variation;
• and
• processes those pressure signals with the flow waveform to determine the impedance to flow.

A system for continuously monitoring impedance to flow in a fluid delivery system in which a flow control device acts on a fluid conduit to control the movement of fluid through the conduit, the flow having a flow waveform, the system comprising:

• a display device;
• a pressure sensor coupled to the conduit for continuously providing pressure signals in response to the pressure sensed in the conduit;
• a processor that:
• receives the pressure signals;
• continuously processes those pressure signals with the flow waveform and continuously determines the impedance to flow based on said processing;
• extracts the resistance from the determined impedance;
• continuously provides display signals to the display device indicative of the resistance measurement;
• wherein the display device displays an indication of the measured resistance.

A system for monitoring impedance to flow in a fluid delivery system in which a flow control device acts on a fluid conduit to control the movement of fluid through the conduit, the flow having a flow waveform, the system comprising:

• a pressure sensor coupled to the conduit for providing pressure signals in response to the pressure sensed in the conduit;
• a processor that:
• receives the pressure signals, processes those pressure signals with the flow waveform and determines the impedance to flow based on said processing;
• reconstructs a pressure signal from the determined impedance;
• compares the reconstructed pressure signal to the received pressure signal and measures the difference between the two;
• provides a low quality indicator in the event that the difference between the reconstructed pressure signal and the received pressure signal exceeds a predetermined threshold.

A system for monitoring impedance to flow in a fluid delivery system in which a flow control device acts on a fluid conduit to control the movement of fluid through the conduit, the flow control device having a movement cycle with a first portion, the flow having a flow waveform, the system comprising:

• a pressure sensor coupled to the conduit for providing pressure signals in response to the pressure sensed in the conduit;
• a processor that:
• receives the pressure signals;
• discards pressure signals occurring in response to the first portion of the flow control device cycle;
• substitutes other pressure signals for the discarded pressure signals;
• and
• processes the remaining pressure signals with the flow waveform to determine the impedance to flow based on said processing.

A system for determining flow impedance in a fluid delivery assembly in which a flow control device acts on a fluid conduit to control the flow of fluid through the conduit, wherein the flow control device provides a selected flow waveform in the fluid flowing through the fluid conduit, the system comprising:

• a pressure sensor coupled to the conduit for providing monitored pressure waveform signals in response to the pressure sensed in the conduit;
• a processor that receives the monitored pressure waveform signals and determines the flow impedance;
• and
• a quality processor that determines the quality of the determined flow impedance.

A system for monitoring at least one flow parameter in a fluid delivery assembly in which a flow control device acts on a fluid conduit to control the flow of fluid through the conduit, the system comprising:

• a pressure sensor coupled to the conduit for providing pressure waveform signals in response to the pressure sensed in the conduit;
• a PRBS encoder that outputs a PRBS code;
• and
• a processor that receives the PRBS code and controls the flow control device to cause flow in accordance with a pattern of flow variation in accordance with the PRBS code, receives the pressure waveform signals, and processes those pressure waveform signals to determine a flow parameter.

A method for monitoring a selected flow parameter in a fluid delivery system in which a flow control device acts on a fluid conduit to control the flow of fluid through the conduit, the method comprising the steps of:

• (a) controlling the flow control device to cause flow in the conduit in accordance with a pseudo-random pattern of flow variation;
• (b) monitoring the pressure in the conduit and providing pressure waveform signals in response to the pressure sensed;
• (c) receiving the pressure waveform signals;
• and
• (d) processing the pressure waveform signals to determine the selected flow parameter.

A system for monitoring impedance to flow in a fluid delivery assembly in which a flow control device acts on a fluid conduit to control the flow of fluid through the conduit, the system comprising:

• a selector for selecting a flow rate;
• a comparator that determines if the selected flow rate is a high or a low flow rate by comparing the selected flow rate to a flow rate threshold;
• a sensor that monitors pressure in the conduit and provides pressure waveform signals in response to the monitored pressure;
• and
• a processor that:
• varies the flow rate about the selected flow rate, with the variation in flow rate a function of whether the flow rate is a high or low flow rate;
• receives the pressure signal waveform;
• and
• calculates the system flow impedance as a function of the pressure waveform signals.

A method for determining system flow impedance in a fluid delivery system in which a flow control device acts on a fluid conduit to control the flow of fluid through the conduit, the method comprising the steps of:

• (a) selecting a flow rate;
• (b) determining if the selected flow rate is a high or low rate by comparing the selected flow rate to a flow rate threshold;
• (c) varying the flow ram about the selected flow ram, wherein for high flow rates the flow rate is varied in accordance with a first selected flow rate pattern, and wherein for low flow rates the flow rate is varied in accordance with a second selected flow rate pattern, the second flow rate pattern differing from the first flow rate pattern;
• (d) monitoring the pressure in the conduit;
• and
• (e) calculating the system flow impedance as a function of the conduit pressure.

A method of determining flow impedance in a fluid delivery system in which a flow control device acts on a fluid conduit to control fluid flow through the conduit, the method comprising the steps of:

• (a) imparting in the fluid conduit a fluid flow having a selected flow waveform;
• (b) monitoring the pressure in the conduit;
• (c) providing an estimated flow waveform corresponding to the selected flow waveform;
• and
• (d) calculating the flow impedance from the monitored pressure and the estimated flow waveform.