Intravenous feeding monitoring system

Claim 2

An intravenous feeding monitoring system comprising, in combination: a. drop rate generating means for connection to the drop chamber of an intravenous feeding apparatus for generating a series of electrical drop pulses at a rate corresponding to the drop rate of fluid in the drop chamber; b. first and second delay means connected to receive said drop pulses and generate first and second delay pulses at the end of first and second time intervals as measured from each drop pulse, said second time interval being greater than said first time interval by an amount from 0.01 to 0.50 of said first time interval so that said first and second delay pulses are separated by a given time window; c. means for adjusting the duration of said first and second time intervals such that the drop pulse following that from which said time signals are measured falls at a point in time within said given time window when said drop rate is at an acceptable frequency; and d. logic circuit means connected to receive said drop pulses and said first and second delay pulses and generate a drop rate alarm in the event the drop pulse following that from which said time intervals are measured falls outside said time window.

Claim 3

A system according to claim 1, including a fluid level indicating means connected to said intravenous feeding apparatus for generating a fluid level alarm signal in the event the level of fluid in said intravenous feeding apparatus falls below a given level.

Claim 4

A system according to claim 2, in which said drop rate alarm is in the form of a series of short duration signals occurring at a frequency corresponding to the drop rate frequency and said fluid level alarm is in the form of a continuous signal.

Claim 5

A system according to claim 1, in which said logic circuit means includes: first and second AND gates having first inputs connected to receive said series of drop pulses; first and second OR gates having first inputs connected to the outputs of said AND gates respectively and second inputs connected to receive said first and second delay pulses respectively; a bistable flip-flop having its input connected to the output of said first OR gate, the first output side of said flip-flop connecting to the second input of said first AND gate, and the second output side of said flip-flop connecting to the second input of said second AND gate; and a monostable flip-flop having its input connected to the output of said second OR gate and its output connected to operate an alarm when its input is triggered by a pulse, whereby a pulse is blocked by said second OR gate from triggering said monostable flip-flop by inhibiting the presence of pulses on its first or second input when the drop rate is of a frequency such that the drop pulse following that from which said time intervals are measured falls within said time window, said second OR gate passing the second delay pulse to trigger said monostable flip-flop when said drop pulse following that from which said time intervals are measured occurs after the second delay pulse and passing a pulse from said second AND gate as a consequence of the enabling of said second AND gate by said bistable flip-flop when said drop pulse following that from which said time intervals are measured occurs before said first delay pulse.

Claim 6

A system according to claim 2, in which said drop rate alarm and fluid level alarm are located at a central station and are connected through already present call button lines to said logic circuit means.