US 11,857,775 B2
Fluid flow system for bubble and fluid detection
Kuna V S R Kishore, Bangalore (IN); Abhishek Joshi, Bangalore (IN); Kumaran S Narasimhan, Bangalore (IN); Kaligaselvi Lenin, Bangalore (IN); Manjunatha Hm, Bangalore (IN); Varun Thakurta, Bangalore (IN); and Sudheer Beligere Sreeramu, Bangalore (IN)
Assigned to HONEYWELL INTERNATIONAL INC., Charlotte, NC (US)
Filed by Honeywell International Inc., Charlotte, NC (US)
Filed on Aug. 6, 2021, as Appl. No. 17/444,620.
Claims priority of application No. 202111028143 (IN), filed on Jun. 23, 2021.
Prior Publication US 2022/0409825 A1, Dec. 29, 2022
Int. Cl. A61M 5/36 (2006.01); G01N 29/032 (2006.01)
CPC A61M 5/365 (2013.01) [G01N 29/032 (2013.01); G01N 2291/02433 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for detecting an air bubble or liquid in a flow tube of a fluid flow system, the method comprising:
monitoring a first output signal of a force sensor of the fluid flow system for a change from the first output signal to a second output signal, wherein the change from the first output signal to the second output signal comprises at least one of a change in amplitude of an Alternating Current (AC) component of the first output signal and a change in a signal level of a Direct Current (DC) component of the first output signal;
detecting the change from the first output signal to the second output signal, wherein the change in the amplitude of the AC component is detected based on an increase or a decrease of the amplitude of the AC component, and the change in the signal level of the DC component is detected based on a shift of the signal level from a first signal level to a second signal level;
determining one of a time duration of the second output signal of the force sensor from an instance the first output signal is changed to the second output signal, and a number of transitions in consecutive signal levels of the DC component from the first signal level to the second signal level;
comparing the time duration of the second output signal with a predefined time and the number of transitions with a predefined number of transitions; and
determining a threshold when one of the time duration of the second output signal exceeds the predefined time, and the number of transitions of the DC component exceeds a predefined number of transitions, wherein the threshold is determined based on a predefined percentage of the second output signal.