Multi-beam liquid-drop size/rate detector apparatus

An apparatus for determining a fluid flow rate in a fluid drop forming system comprising:

• energy beam emission means for directing first and second energy beams across a path of a free falling fluid drop with each energy beam having a predetermined height and with an upper surface of the first energy beam separated from an upper surface of the second energy beam by a predetermined distance (k);
• energy beam detection means for receiving the first and second energy beams and for generating signals in response to the fluid drop entering or exiting from a path of the first or second energy beams;
• timing means for receiving signals from the energy beam detection means and for measuring a time interval (t1) for the fluid drop to traverse the first beam, a time interval (t2) for the fluid drop to travel from a point within the first beam to a point within the second beam and a time interval (t3) for the fluid drop to travel through the first and second beams;
• and
• microprocessing means for receiving signals from the energy beam detection means and the timing means and for calculating an approximate diameter (dd) of the fluid drop from mathematical relationship between the predetermined heights of the energy beams, the predetermined distance (k), the time intervals (t1, t2, t3) and a gravitational constant (g) and then for calculating a fluid drop volume and a fluid flow rate.

In an IV administration system having a fluid source fluidly connected to a drop forming orifice adapted to direct fluid drops from the fluid source in free fall through a drip chamber in fluid communication with an IV tube connected to a patient, a system for measuring fluid flow comprising:

• energy beam emission means for directing an upper beam of a predetermined height (A) and a lower beam of a predetermined height (B) across the path of fluid drops falling through the drip chamber with the beams having upper surfaces separated by a predetermined distance (k);
• energy beam detection means for receiving the first or second energy beams and for generating signals in response to the fluid drops entering and exiting the path of the energy beams;
• timing means for receiving signals from the energy beam detection means and for timing a time interval (t1) for a drop to pass through the first beam, a time interval (t2) for the drop to pass from an upper surface of the first beam to an upper surface of the second beam and a time interval (t3) for the drop to pass through the upper and lower beams;
• and
• processing means for receiving signals from the energy beam detection means and timing means and for calculating the fluid flow rate based on mathematical relationships between the predetermined heights (A and B), the predetermined distance (k), the time intervals (t1, t2, t3) and a gravitational constant (g).