Flow rate monitor with optical sensing chamber

For use in a gravity intravenous administration system, a drop sensing chamber, said chamber comprising:

• a hollow housing made up of a plurality of vertically extending wall portions defining a hollow cavity;
• orifice means for introducing an IV solution as a series of drops into said cavity, said orifice means oriented so that said drops under gravity pass through said cavity;
• first and second of said wall portions arranged opposite each other;
• first lens means defined on said first wall portion;
• and
• second lens means defined on said second wall portion, said first and second lens means arranged relative to each other to cause a light beam passing through them to be arranged as a series of parallel light rays within said cavity and defining a plane generally perpendicular to the path defined by the passing drops.

An intravenous administration system comprising:

• a drop detection chamber;
• sensing means for sensing the passage of drops of IV solution through said chamber;
• a flexible tubing having one end in fluid communication with said chamber and the other end adapted to be connected in fluid communication with a source of IV solution, said one end of said tubing defining a drop former within said chamber;
• actuator means responsive to control signals for constricting and opening the hollow interior of said flexible tubing;
• and
• control means for issuing said control signals to cause said actuator means to operate in such fashion that, while the system is administrating IV solution, said hollow interior is never completely constricted, but is closed only to such an extent that internal friction within the tube just prevents the formation of additional drops at said drop former within said chamber.

In an intravenous administration system having a drop detection chamber, an apparatus for controlling the passage of drops of IV solution through the chamber, said apparatus comprising:

• sensing means for sensing the passage of said drops of IV solution through said chamber;
• a flexible tubing having one end in fluid communication with said chamber and the other end adapted to be connected in fluid communication with a source of IV solution, said one end of said tubing defining a drop former within said chamber;
• actuator means responsive to control signals for constricting and opening the hollow interior of said flexible tubing;
• and
• control means for issuing said control signals to cause said actuator means to operate in such fashion that, while the system is administrating IV solution, said hollow interior is never completely constricted, but is closed only to such an extent that internal friction within the tube just prevents the formation of additional drops at said drop former within said chamber.

A flow monitor, said monitor comprising:

• a drop chamber for observing the passage of solution from a source to a collection site, said drop chamber including means for introducing said solution into said chamber as a series of drops;
• producing means for producing a light beam;
• means for directing said light beam through said chamber;
• receiving means for receiving said light beam after it passes through said chamber and for issuing a drop volume signal indicative of the volume of a drop passing through said chamber, said producing and receiving means each subject to electronic drift;
• and
• means for compensating said drop volume signal for electronic drift introduced by said producing and receiving means.

A flow monitor for measuring precise volumes of fluid, said monitor comprising:

• a sensing chamber including a hollow housing made up of a plurality of vertically extending wall portions defining a hollow cavity;
• orifice means for introducing fluid as a series of drops into said cavity, said orifice means oriented so that said drops under gravity pass through said cavity;
• first and second of said wall portions arranged opposite each other;
• first lens means defined on said first wall portion;
• and
• second lens means defined on said second wall portion, said first and second lens means arranged relative to each other to cause a light beam passing through them to be arranged as a series of parallel light rays within said cavity and defining a plane generally perpendicular to the path defined by the passing drops.

An intravenous administration system comprising:

• a drop detection chamber;
• sensing means for sensing the passage of drops of IV solution through said chamber;
• measuring means for measuring the volume of drops sensed by said sensing means;
• means for determining whether the volume of each drop as measured by said measuring means is within a predetermined range of drop volumes;
• a flexible tubing having one end in fluid communication with said chamber and the other end adapted to be connected in fluid communication with a source of IV solution;
• actuator means responsive to control signals for altering the cross-sectional size of the hollow interior of said flexible tubing;
• drop forming means for forming drops which are introduced into said drop detection chamber for passage past said sensing means, the size of the formed drops being proportional to the size of the cross-section of said flexible tubing;
• control means for issuing said control signals to cause said actuator means to alter the cross-section of said flexible tubing in such fashion that, while the system is administrating IV solution, the time interval between drops is altered when the volume of the measured drops is within said predetermined range and the volume of said drops is altered when the volume of the measured drops is outside of said predetermined range.

For use in a flow monitor for measuring precise volumes of fluid, a drop sensing chamber, said chamber comprising:

• a sensing chamber including a hollow housing made up of a plurality of vertically extending wall portions defining a hollow cavity;
• orifice means for introducing fluid as a series of drops into said cavity, said orifice means oriented so that said drops under gravity pass through said cavity;
• first and second of said wall portions arranged opposite each other;
• first lens means defined on said first wall portion;
• and
• second lens means defined on said second wall portion, said first and second lens means arranged relative to each other to cause a light beam passing through them to be arranged as a series of parallel light rays within said cavity and defining a plane generally perpendicular to the path defined by the passing drops.