Abstract: The present invention relates to a failure alarm system for an intravenous feeding pump in which the pumping force is secured by the projection of a plunger into a chamber filled with the liquid to be pumped, which plunger is encased in a tightly fitting sheath of elastic material. In such a pump, actuation is secured by the application of a force from an actuator to the end of the plunger extending without the wall of a pumping chamber and the return force is secured by the elasticity of the sheath. The actuator of such a pump provides an actuator which can be selectively set to provide an extended range of operations per unit of time and can be modified to control the amount of projection into the pumping chamber by the plunger. In such a combination means is provided by the present invention for sensing the fact that there is a negative pressure, or suction, in the system that is not balanced by the in-flow of liquid, i.e.

Abstract: A constant flow rate liquid medicament administering device which includes a container having a liquid medicament therein. The liquid medicament is fed under pressure to a constant output flow rate regulator that is operated by a drop in pressure between its inlet and outlet. The liquid leaving the regulator under reduced pressure and at a constant flow rate independent of entering pressure is led to a drip chamber in which any gas entrapped in the liquid is released so as to prevent introduction of gas into a patient. The drip rate in the chamber furnishes a rough visual indication of flow rate, the regulator being adjustable to secure any desired rate. Either before or after passage of the liquid through the drip chamber, the liquid is passed through a flow rate indicator which more accurately provides an instantaneous reading of flow rate. Finally, the liquid is led to an administering implement for introducing the liquid into a patient at a constant flow rate.

Abstract: An electronically controlled intravenous infusion set of the gravity feed type having a flow path including a drip chamber and an internal valve for regulating flow through the set. Electromagnetic valve operating structure, positioned outside the IV set, controls the internal valve in response to an electronic control system. The electronic control system serves to open the valve to allow a drop to fall, and includes a control circuit. The control circuit includes an optical drop detector, associated with but positioned outside the drip chamber, which senses the falling drop and signals the control circuit to close the valve. The control circuit also includes a variable frequency clock and associated digital selectors for affording an attendant the ability to precisely select a desired drip rate. An alarm system, operating on digital principles, senses high drop rate or low drop rate conditions and, in response thereto, puts the control system into an alarm condition.

Abstract: An electronically controlled, gravity-feed, intravenous infusion set in which a length of intravenous tubing is connected with a drip chamber to convey a fluid to be administered intravenously, the improvement comprising a normally closed internal valve in said set operable to prevent flow of fluid through the set and operated to open position to enable passage of a drop of fluid through the set, and an electrically controlled actuator operatively associated with the valve to operate the valve to its open position at a predetermined frequency of operation and to hold the valve open until a drop forms and falls to thus determine the drip rate of fluid through the set, said internal valve thus enabling control of flow of fluid through the set without necessitating crimping or other deformation of the set and thereby resulting in dependable and accurate control of the flow rate of the fluid to be administered intravenously.

Abstract: A digital system wherein a wide variety of different electromechanical output control devices, e.g., stepping motor pump or solenoid actuated I.V. tube pincher, is driven by electrical output pulses of varible frequency and pulse width from a digital pulse generation and control system, the frequency and pulse width of the output pulses being selected and controlled by the system to establish drop flow rates with digital precision over an extremely wide dynamic range. Pulse width is determined by the relative states of a pair of digital counters in a digital memory, frequency being determined by a high, preferably non-integral, multiple of the desired drop flow rate. The equivalent of negative pulse width in the digital memory can be effectively utilized to expand the effective dynamic range of the memory for specified types of electromechanical output devices. A start up subsystem temporarily presets the initial pulse rate and speeds up early regulation.

Abstract: The flow rate regulation, notably of a rapid perfusion flow rate, is effected by regulating the pressure in the perfusion reservoir by the application of a voltage to a compressor, which increases the flow rate of the liquid in the perfusion tubing by sending pressurized air into the reservoir. The latter is at atmospheric pressure when no voltage is applied to the compressor. The device comprises the combination of a perfusion reservoir and a compressor which causes the pressure in said reservoir to vary. Consequently the flow rate of the perfusion liquid delivered by the latter into the perfusion tubing varies. The compressor is governed by a differential voltage resulting from the comparison by an electronic circuit of the real value with the desired value of the flow rate in the perfusion tubing. This differential voltage is applied to the compressor which then sends compressed air into the perfusion reservoir.

Abstract: A flow rate controlled angiographic injection system is provided with an overspeed injection protection means. The injection system includes a motor driven syringe injector and a flow rate controller responsive to the overspeed protection means to drive the motor to inject a contrast medium from the syringe into a blood vessel at a desired flow rate when the actual flow rate from the syringe is less than or equal to the predetermined flow rate, and to disable the motor otherwise. The overspeed injection protection means includes a means for generating a signal representative of the actual flow rate of a contrast medium from the syringe by detecting the back emf induced in the motor armature, compensation being made for the resistive voltage drop in the armature windings and brushes.

Abstract: An automatic metering apparatus for selecting and controlling the flow rate of liquids, particularly for medical purposes, to be arranged between a liquid feeding container and a perfusion or transfusion line, comprises an electronic timer device capable of being pre-set from the outside in order to pre-select the flow rate of the liquid drops to be metered. A sequential electronic controlling circuit has its inputs connected to the outputs of the timer device, while its outputs control an actuator for causing liquid drops to inflow into the perfusion or transfusion line. An optic-electronic transducer is also provided for detecting the flow rate of the drops, the output of which is fed back to the input of the sequential circuit. The apparatus also comprises a counting device and at least one alarm device.

Abstract: Apparatus for monitoring the drop of the level of the liquid in a plastic bag that is used during the intravenous administration of a solution includes a housing in which switch means having an integral, spring actuated contact means is mounted with the switch means being electrically connected to alarm means for generating a signal when the condition of the switch means changes in response to the reduction of the contents of the bag to a predetermined volume. A first arm is pivotally mounted so that a portion of the first arm engages a first surface of the bag. First spring means are employed for normally biasing the first arm in a direction towards the first surface of the bag. A second arm includes a portion that is in opposition to the bag engaging portion of the first arm so that the bag may be positioned therebetween and compressed thereby. The second arm also includes means for actuating the switch means.

Abstract: An apparatus, for example, an intravenous drop-feed apparatus for sensing the rate at which liquid drops fall along a predetermined vertical path and for regulating this drop rate to be substantially equal to a preselected drop rate includes a disposable drip chamber which defines a vertical drop path. The drip chamber is formed with an indentation having an upper wall that projects into the drop path to be impinged by drops falling on its interior surface. A probe is removably mounted on the outside of the chamber in interfitting engagement with the chamber indentation and includes an electrically conductive element located to contact the exterior surface of the upper indentation wall. The element, which is electrically but not thermally isolated from falling drops, exhibits conductivity that varies significantly with its temperature and, accordingly, generates pulses at a rate that corresponds to the periodic rate of the falling drops.

Abstract: Apparatus for actuating an alarm to alert medical personnel that an intravenous fluid has been fully administered to the quantity ordered by the attending physician. A liquid dispensing container secured to one side of a balance arm with a counterweight secured to the other side of the balance arm opposite the fulcrum about which the balance arm is pivotally secured such that when balanced, a magnet on the balance arm actuates a switch, closing an electrical circuit to energize an alarm which alerts attending personnel. The fulcrum pin is secured to a support member which is secured to a support such as an IV stand.

Abstract: An alarm system operative in conjunction with a venocylsis set which includes a drop chamber coupled to the output of a fluid bottle. The alarm system is provided with a float disposed in the drop chamber and responsive to the level of fluid pool therein. A proximity switch sensitive to the float position is removably attached to the exterior of the drop chamber to produce a switching action when the fluid level falls below a predetermined value. An alarm circuit is coupled to the proximity switch to generate a warning signal when the switching action occurs.

Abstract: A device for detecting the presence of air bubbles within a fluid-carrying tube, for example a blood tube used in medical procedures. The tube is placed between a light source and an optical sensor which produces signals when bubbles pass through the tube. These signals are integrated and a switch changes state when the integration reaches a predetermined value. The detector thus responds to a predetermined quantity of air, either by a large air bubble or an accumulation of small air bubbles. In a preferred embodiment, the switch releases a springloaded clamp which pinches off the tube when an excessive amount of air is detected.