Determining fluid flow across rotary pump

Patent metadata

Field	Value
Publication number	US-11965763-B2
Application number	US-202117525720-A
Country	US
Kind code	B2
Filing date	Nov 12, 2021
Priority date	Nov 12, 2021
Publication date	Apr 23, 2024
Grant date	Apr 23, 2024

Abstract

Systems, devices, and methods are provided for measuring fluid flow across a pump used in a system for precisely and accurately metering fluid. The systems, devices, and methods can use contactless approaches to measure the properties of the fluid being pumped. The measured properties can be used to precisely and accurately determine the flow rate through the pump.

First claim

What is claimed is:

1. A system for fluid flow, comprising:
a rotary pump;
an inflow line and an outflow line in fluid communication with the rotary pump;
an inlet pressure sensor at the inflow line;
an outlet pressure sensor at the outflow line;
a current sensor measuring current drawn by the rotary pump; and
a circuit calculating fluid flow rate through the system based on a density value for a fluid pumping through the system, rotational speed of the rotary pump, inlet pressure at the inflow line, outlet pressure at the outflow line, and current drawn by the rotary pump.

2. The system of claim 1 , further comprising a temperature sensor measuring a temperature of the fluid pumping through the system, the density value for the fluid determined from the measured temperature.

3. The system of claim 2 , wherein the fluid is peritoneal dialysis fluid, and wherein the density value for the liquid is a known value for the density of peritoneal dialysis fluid at the measured temperature.

4. The system of claim 2 , wherein the inlet pressure sensor, the outlet pressure sensor, and the temperature sensor are each non-intrusive sensors.

5. The system of claim 4 , the circuit determines a resistance for the rotary pump based on the rotational speed of the rotary pump and the current drawn by the rotary pump, the determined resistance relating a known voltage of the rotary pump to the drawn current.

6. The system of claim 1 , the rotary pump having a driver controlling the rotational speed of the rotary pump, the driver communicating the rotational speed of the rotary pump to the circuit calculating the liquid flow rate through the system.

7. The system of claim 1 , wherein the circuit determines fluid flow, Q, to an area A within the inflow line and a velocity v of fluid flow within the inflow line according to the equation: Q=A*v.

8. The system of claim 1 , wherein the circuit determines fluid flow, Q, to an area A within the outflow line and a velocity v of fluid flow within the outflow line according to the equation: Q=A*v.

9. The system of claim 1 , the circuit relating the inlet pressure, p o , the outlet pressure, p i , and the fluid density value, ρ, according to the equation:
v i 2 /2 +g*h i +p i /ρ=v o 2 /2 +g*h o +p o /ρ

where v i is the velocity of fluid flow within the inflow line, v o is the velocity of flow within the outflow line, g is the acceleration due to gravity, h i is the height of the inflow line, and h o is the height of the outflow line.

10. A method for determining fluid flow across a rotary pump, comprising:
calculating a fluid flow rate based on a rotational speed of the rotary pump, a pressure difference between a fluid intake and fluid discharge across the rotary pump, a determined density value for the fluid, and a measured current drawn by the rotary pump.

11. The method of claim 10 , further comprising the steps of:
calculating a pressure difference between a fluid inflow line and a fluid outflow line based on a measured suction pressure at the fluid inflow line in fluid communication with the rotary pump and a discharge pressure at the fluid outflow line in fluid communication with the rotary pump.

12. The method of claim 10 , further comprising the steps of:
measuring the current, I, drawn by the rotary pump; and
comparing the drawn current and a known voltage, V, of the rotary pump to the rotational speed of the rotary pump to determine a resistance, R, for the rotary pump according to the following equation: V=I*R
wherein the fluid flow is calculated based on the determined resistance.

13. The method of claim 10 , further comprising the step of displaying the calculated fluid flow rate.

14. The method of claim 10 , wherein the density value for fluid moving across the rotary pump is determined by measuring a temperature for the fluid and calculating the density based on the measured temperature.

15. The method of claim 10 , wherein the rotational speed of the rotary pump is measured by a driver regulating the speed of the rotary pump.

16. The method of claim 10 , further comprising the step of calculating the fluid flow, Q, by relating to an area A within an inflow line and a velocity v of fluid flow within an inflow line according to the equation: Q=A*v.

17. The method of claim 10 , further comprising the step of calculating the fluid flow, Q, by relating to an area A within an outflow line and a velocity v of fluid flow within an outflow line according to the equation: Q=A*v.

18. The method of claim 10 , further comprising the step of calculating the fluid flow by relating an inlet pressure, p o , an outlet pressure, p i , and the fluid density value, ρ, according to the equation:
v i 2 /2 +g*h i +p i /ρ=v o 2 /2 +g*h o +p o /ρ

where v i is the velocity of fluid flow within an inflow line, v o is the velocity of flow within an outflow line, g is the acceleration due to gravity, h i is the height of the inflow line, and h o is the height of the outflow line.

19. The method of claim 10 , further comprising the steps of:
applying current drawn by the rotary pump and temperature of the fluid as independent variables in modeling the fluid flow across the pump; and calculating the fluid flow based on the modeling.

20. The method of claim 19 wherein a measured suction pressure at an inflow line and a measured discharge pressure at an outflow line are independent variables in modeling the fluid flow across the pump.

Assignees

• Mozarc Medical Us Llc

Inventors

• Nellikunje Krishnaraja
• Jain Hemanth Kumar
• Gunasekaran Thisanth

Classifications

• G01F1/88 Primary

  with differential-pressure measurement to determine the volume flow · CPC title

• G01F1/06

  using rotating vanes with tangential admission · CPC title

• G01F1/50

  Correcting or compensating means · CPC title

• G01F1/34 Primary

  by measuring pressure or differential pressure · CPC title

• G01F3/08

  Rotary-piston or ring-piston meters · CPC title