APPARATUS FOR REGULATING THE AMOUNT OF LIQUID ADMINISTERED PER UNIT TIME

• US 3,790,042 A
• Filed: 09/15/1970
• Issued: 02/05/1974
• Est. Priority Date: 09/15/1970
• Status: Expired due to Term

• Current Assignee: The Kendall Company (Colgate-Palmolive Company)
• Original Assignee: James B. Mccormick, Shunjiro Ohba
• Inventors: McCormick, James B., Ohba, Shunjiro
• Primary Examiner(s): Tollberg, Stanley H.
• Assistant Examiner(s): Slattery, James M.
• Application Number:
  US05/072,313
• Time in Patent Office: 1,239 Days
• Field of Search: 222/52,59,63,71 128/214E,DIG.13 73/194EM,194E,432PS 324/71CP 340/239R 137/486,487.5,244
• US Class Current: 222/52
• CPC Class Codes: A61M 5/1689 Drip counters

Abstract

A regulating apparatus for regulating the amount of liquid administered per unit time to a recipient by an administering apparatus. The administering apparatus includes a drip chamber connected by means of a delivery tube to a supply of drops of liquid and by a second delivery tube to a device for transferring the liquid to a recipient. The regulating apparatus comprises a first means which senses the drops of liquid passing through the drip chamber and which produces pulses representing the number of drops. The pulses produced by the sensing means are accumulated in a second means which produces a first signal related to the number of pulses received per unit time. The amplitude of the first signal is changed by a third means at a rate related to a preselected drip rate. A fourth means is provided for generating a reference signal which is compared in a fifth means to the changed amplitude of the first signal, the fifth means producing the third signal related to the difference between the signals. The third signal is fed to a sixth means which supplies the proper current to a bi-directional motor to drive the motor in one direction when the changed first signal is less than the reference signal and to drive the motor in the opposite direction when the changed signal is greater than the reference signal. The bi-directional motor is connected to a valve or clamp which is disposed on the delivery tube so as to vary the amount of liquid flowing through the tube. Thus, if the drip rate becomes greater than the preselected rate, the valve is moved toward a closed position by the motor to reduce the drip rate, while if the drip rate is less than the preselected rate, the valve is moved toward the open position to increase the drip rate.

Claims

1. Apparatus for regulating the amount of liquid administered per unit time to a recipient by an administering apparatus including a drip chamber through which drops of liquid flow in relation to the rate of liquid being administered and a valve controlling the rate of liquid being administered, said regulating apparatus comprising first means for sensing the drops of liquid passing through the drip chamber and producing pulses representing the number of drops, second means for accumulating said pulses and producing a first signal related to the number of pulses received per unit of time, third means for changing the amplitude of said first signal at a rate related to a preselected drip rate, a bi-directional motor connected to said valve, fourth means for generating a reference signal, fifth means for comparing the changed amplitude of said first signal with said reference signal and producing a third signal related to the difference between the signals, and sixth means responsive to said third signal for driving said motor in one direction when said changed signal is greater than the reference signal and in the other direction when said changed first signal is less than said reference signal.

2. A regulating apparatus in accordance with claim 1 in which the second means is a capacitor which is charged by each pulse, and said third means is a resistor connected so as to discharge said capacitor.

3. A regulating apparatus in accordance with claim 1 in which a monitoring circuit is provided which includes an indicating means and a sixth means connected between said indicating means and said first means for actuating said indicating means in response to each pulse.

4. A regulatiNg apparatus in accordance with claim 1 in which said first means includes a drip detector in the drip chamber for sensing each drop and providing an unregulated pulse for each drop and a monostable multivibrator coupled to said drip detector for providing a regulated pulse for each unregulated pulse received therein, the output of said multivibrator being coupled to said second means.

5. A regulating apparatus in accordance with claim 4 in which the second means is a capacitor which is charged by each pulse, and said third means is a resistor connected so as to discharge said capacitor.

6. Apparatus for regulating the amount of liquid administered per unit time to a recipient by an administering apparatus including a drip chamber through which drops of liquid flow in relation to the rate of liquid being administered and a valve controlling the rate of liquid being administered, said regulating apparatus comprising first means for sensing the drops of liquid passing through the drip chamber and producing pulses representing the number of drops, said first means including a drip detector in the drip chamber for sensing each drop and providing an unregulated pulse for each drop and a monostable multivibrator coupled to said drip detector for providing a regulated pulse for each unregulated pulse received therein, second means coupled to the output of said multivibrator for accumulating said pulses and producing a first signal related to the number of pulses received per unit time, third means for changing the amplitude of said first signal at a rate related to a preselected drip rate, a bi-directional motor connected to said valve, fourth means for generating a reference signal, fifth means for comparing the changed amplitude of said first signal and said reference signal and producing a third signal related to the difference between the signals, sixth means responsive to said third signal for driving said motor in one direction when said changed signal is greater than the reference signal and in the other direction when said changed first signal is less than said reference signal and a first safety circuit including an amplifier having an integrating circuit in its input, the input of said integrating circuit being connected to said first drip detector and the output of said amplifier being connected to said multivibrator to switch said multivibrator to a mode such as to close said valve.

7. A regulating apparatus in accordance with claim 6 in which a phase advance circuit is connected at the input of said fifth means so as to advance the phase of the changed signal.

8. Apparatus for regulating the amount of liquid administered per unit time to a recipient by an administering apparatus including a drip chamber through which drops of liquid flow in relation to the rate of liquid being administered and a valve controlling the rate of liquid being administered, said regulating apparatus comprising first means for ensing the drops of liquid passing through the drip chamber and producing pulses representing the number of drops, second means for accumulating said pulses and producing a first signal related to the number of pulses received per unit time, third means for changing the amplitude of said first signal at a rate related to a preselected drip rate, a bi-directional motor connected to said valve, fourth means for generating a reference signal, fifth means for comparing the changed amplitude of said first signal with said reference signal and producing a third signal related to the difference between the signals, a phase advance circuit at the input of said fifth means for advancing the phase off the changed signal, and sixth means responsive to said third signal for driving said motor in one direction when said changed signal is greater than the reference signal and in the other direction when said changed first signal is less than said reference signal.

9. A regulating apparatus in accordance with claim 8 wherein said fifth means is an operational amplifier having A high gain for slow minor changes from a steady state condition, a high gain for fast changes from a steady state condition and a low gain for intermediate changes.

10. Apparatus for regulating the amount of liquid administered per unit time to a recipient by an administering apparatus including a drip chamber through which drops of liquid flow in relation to the rate of liquid being administered and a valve controlling the rate of liquid being administered, said regulating apparatus comprising first means for sensing the drops of liquid passing through the drip chamber and producing pulses representing the number of drops, second means for accumulating said pulses and producing a first signal related to the number of pulses received per unit time, third means for changing the amplitude of said first signal at a rate related to a preselected drip rate, a bi-directional motor connected to said valve, fourth means for generating a reference signal, fifth means for comparing the changed amplitude of said first signal with said reference signal and producing a third signal related to the difference between the signals, and sixth means responsive to said third signal for driving said motor in one direction when said changed signal is greater than the reference signal and in the other direction when said changed first signal is less than said reference signal, said first means including seventh means for establishing a horizontal magnetic field across said drip chamber, thee extent of the field in the vertical direction being small, a disc of faromagnetic material disposed in said drip chamber, said disc being smaller than the internal diameter of the drip chamber, an eighth means for sensing changes in the magnetic field produced by movement of said disc caused by drops striking said disc.

11. Apparatus for regulating the amount of liquid administered per unit time to a recipient by an administering apparatus including a drip chamber through which drops of liquid flow in relation to the rate of liquid being administered and a valve controlling the rate of liquid being administered, said regulating apparatus comprising first means for sensing the drops of liquid passing through the drip chamber and producing pulses representing the number of drops, said first means including a drip detector in the drip chamber for sensing each drop and providing an unregulated pulse for each drop and a monostable multivibrator coupled to said drip detector for providing a regulated pulse for each unregulated pulse received therein, a second means connected to the output of said multivibrator for accumulating said pulses and producing a first signal related to the number of pulses received per unit time, said second means including a capacitor which is charged by each pulse, third means for changing the amplitude of said first signal at a rate related to a preselected drip rate, said third means being a resistor connected so as to discharge said capacitor, a bi-directional motor connected to said valve, said third means including a resistor connected so as to discharge said capacitor, fourth means for generating a reference signal, fifth means for comparing the changed amplitude of said first signal with said reference signal and producing a third signal related to the difference between the signals, a phase advance circuit connected at the input of said fifth means for advancing the phase of the changed signal, and sixth means responsive to said third signal for driving said motor in one dirction when said changed signal is greater than the reference signal and in the other direction when said changed first signal is less than said reference signal.

12. A regulating apparatus in accordance with claim 11 wherein said fifth means is an operational amplifier having a high gain for slow, minor changes from a steady state condition, a high gain for fast changes from a steady state condition and a low gain for intermediate changes.