Imed Corporation

Jon A Jenkins

Larry L Wilson

Oscar E Hyman

Raymond E Cannon

Clinton L Deckert

Herbert A Schwan

Orris H Flatten

Apparatus controls the rate of passage of fluid drops through a drip controller in accordance with a preset rate. When the rate of passage of the fluid drops is less than the preset rate, a stepper motor is incrementally operated at progressive instants of time to open the drip chamber until the measured rate is equal to the preset rate. When the rate of passage of the fluid drops is greater than the preset rate, the stepper motor is operated instantaneously to close the passage through a number of increments corresponding to the difference in the measured and preset rates. An alarm is energized when the stepper motor is positioned to provide for a maximum flow of fluid and the rate is still below the preset rate. An alarm is also energized when the passage is closed and the preset rate indicates a desired flow of fluid. An emergency motor is also provided to control the opening in the passage. Before the operation of the apparatus is instituted, the stepper motor is operated to close the drip chamber. The emergency motor is then operated to open the drip chamber and thereafter close the drip chamber. The emergency motor may thereafter be operated to close the passage when the drop controller fails to meet certain standards.

Drop controller

Apparatus provides a controlled flow of fluid at particular rates from a source to a patient at controlled pressures of low value. The apparatus includes an input line connected to the source. An output line extends to the patient and implementing means such as a pump implements the flow of fluid from the input line to the output line at a particular rate. The source is disposed a particular distance above the implementing means to produce a particular pressure of the fluid at the implementing means and to provide this particular pressure to the fluid flowing to the patient. A bypass line is connected across the implementing means. Means in the bypass line, such as a chamber and a flexible diaphragm in the chamber, isolate the input side of the bypass line against the flow of fluid to the output side of the bypass line. Hydrophilic membrane means may be provided between the bypass line and the implementing means to provide for a passage of fluid from the input line to the bypass line and to prevent a passage of air bubbles from the bypass line to the input line. Hydrophilic membrane means may also be provided between the output line and the bypass line for similar purposes. Means may be disposed in the output side of the bypass line to sense the presence of liquid. Such sensing of liquid indicates a pressure of fluid in the output line greater than the pressure of the fluid in the input line at the position of the implementing means. This may result from an obstruction in the output line or an improper operation of the implementing means. When the sensing means becomes operative, the operation of the implementing means is discontinued and aural and/or visual alarms are energized.

Apparatus for providing a controlled flow of intravenous fluid to a

Apparatus controls the maximum pressure of the fluid which can flow through a pump. The apparatus includes a disposable unit with an inlet for receiving fluid from a source, an outlet for transferring the fluid to a patient and a chamber communicating between the inlet and the outlet. A diaphragm across the chamber is constrained in accordance with the pressure of the fluid in the chamber. The diaphragm transmits the constraint to a stiffener. The disposable unit is removably attached to the pump casing. A knob is externally disposed on the pump casing and is adjustable to control the maximum force of the fluid in the disposable unit. The knob controls the force exerted on biasing means in a first direction. A force is also exerted against the biasing means in a second direction opposite to the first direction. This force is dependent upon the force on the stiffener. The biasing means may include a spring. The force on the biasing means in the first direction is provided by a back-up member which is pivotable at one end and is disposed against the spring at an intermediate position and is provided with an adjustable lever arm dependent upon the adjustment of the knob. The force in the opposite direction is transmitted by the stiffener to a diaphragm in the pump casing. This diaphragm in turn transmits the force to a vane which is pivotable at one end and is disposed against the spring at an intermediate position. Sensor means are coupled to the vane to provide an output indication after the vane has overcome the bias provided on the spring in the first direction.

Apparatus for converting a pump to a controller

A rate meter senses successive drops of fluid flowing through a conduit and produces gating periods with time durations corresponding to the period of time between such successive drops. The rate meter then determines the number of incremental time periods in each gating period. The rate meter generates the reciprocal of this determination to obtain an indication of the rate of fluid flow. The rate meter may be self-contained. It includes a housing having a vertically disposed channel constructed to retain the conduit and a horizontally disposed channel communicating with the vertically disposed channel. The horizontally disposed channel is constructed to receive a cross bar made from a resilient material and fixedly disposed on the conduit. The cross bar supports the rate meter in a freestanding relationship. The cross bar may be provided with slots near its ends to enhance its resiliency. The cross bar may also be provided with detents at its ends to cooperate with detents at the ends of the horizontally disposed channel on the rate meter to retain the rate meter on the cross bar. The vertically disposed channel in the rate meter may be defined by first and second oppositely disposed walls in the housing. A light source may be disposed in the first wall and a light sensor may be disposed in the second wall. Visual indicating means may be disposed on a front wall of the housing to provide a numerical indication of the rate of fluid flow.

Rate meter

Apparatus is provided for assuring that fluid is introduced from a pump to a receiver, such as a patient, at a controlled and safe pressure. This arrangement includes conduit means, such as inlet and outlet lines, which extend from the pump to the receiver and which are included in a disposable unit. The disposable unit includes detent means cooperative with detent means in the pump to hold the disposable unit in releasable relationship with the pump. Resilient means such as diaphragm are disposed in the conduit means in the disposable unit. The resilient means expand or contract in accordance with the pressure of the fluid in the outlet line. Actuatable means such as an actuatable arm is disposed in the disposable unit and is captured in the conduit means and is positioned in abutting relationship with the diaphragm for movement with the diaphragm. When the pressure of the fluid in the output line reaches a particular value, the actuating arm becomes displaced through a particular distance to operate sensing means external to the disposable unit. The operation of the sensing means causes an output indicator to be energized. The particular pressure for operating the sensing means is dependent upon the adjustable positioning of control means, such as a knob, external to the disposable unit. The manual adjustment of the knob causes a control member to be adjusted in position. The adjustment in the position of the control member may produce a corresponding adjustment in the force required to actuate the arm, thereby producing an adjustment in the fluid pressure at which the sensing means becomes operative.

First and second means respectively provide for a passage of first and second particular volumes of fluid from first and second sources at first and second controlled rates to a patient. Each of the first and second means is constructed to provide on a positive basis for the flow of fluid at the particular one of the first and second controlled rates. Third means are operatively coupled to the first and second means for providing for an initial operation of the first means in producing a passage of fluid from the first source to the patient. Fourth means are responsive to the passage of the first particular volume of fluid to the patient for interrupting the operation of the first means and instituting the operation of the second means in providing for the passage of fluid from the second source to the patient. The passage of fluid from the first means to the patient is also interrupted when all of the fluid has passed from the source. At such a time, an air sensor associated with microbore tubing indicates that fluid is no longer passing through the tubing. At such a time, however, a drip chamber receiving the fluid from the microbore tubing still has fluid because the volume of the drip chamber is greater than the volume of the microbore tubing. Since the fluid from the drip chamber is introduced to the first means for passage on a controlled basis to the patient, the air sensor becomes operative to interrupt the flow of fluid to the patient at a time when air bubbles cannot flow to the patient. The drip chamber is made from a resilient material so that it can be initially operated to squeeze into the source any air bubbles existing in the drip chamber before fluid starts to pass from the first source to the patient.

Apparatus for providing a controlled introduction of intravenous fluid

A controller provides precisely regulated flow of intravenous fluid on a gravitational basis to a patient. The controller includes a storage chamber with first and second compartments and a diaphragm separating the compartments and movable in the chamber to vary the volumes of the first and second compartments. The storage chamber may be disposed in a replaceable cassette. Control means provide at first times for the introduction of fluid from the source to the first compartment and the passage of fluid from the second compartment to the patient. The control means provide at other times for the introduction of fluid from the source to the second compartment and the passage of fluid from the first compartment to the patient. The control means may also be included at least partially in the cassette. Means operate upon the control means, upon the movement of the diaphragm to a particular position in the second compartment, to obtain the introduction of fluid from the source to the first compartment and the passage of fluid from the second compartment to the patient. Such means operate on the control means, upon the movement of the diaphragm to a particular position in the first compartment, to obtain the introduction of fluid from the source to the second compartment and the passage of fluid from the first compartment to the patient. The control means also control at each instant the rate at which fluid flows from each of the compartments to the patient by comparing at such instant desired and actual rates of fluid flow and by providing adjustments in accordance with such comparison.

System for controlling the flow of intravenous fluids to a patient

A volumetric infusion pump for intravenous administration of fluid to a patient, including a volumetric cassette for receiving fluid from an IV fluid container and for pumping such fluid at a controlled rate using an IV administration set until a predetermined volume of fluid has been infused into the patient. The volumetric cassette contains, when filled, a predetermined volume of fluid. The cassette, when coupled to a driving mechanism in the pump, provides for the fluid to be pumped from the cassette at a predetermined rate. Once the cassette chamber has been at least partially emptied a predetermined amount by the operation of the pump, the volumetric chamber of the cassette is rapidly filled and the pumping continues with such emptying and filling of the cassette chamber alternately occurring until the predetermined volume of fluid has been pumped. The cassette is of a syringe type having a chamber and a plunger piston and the stroke of the plunger is controlled by the driving mechanism of the pump. A plurality of alarm mechanisms provide safety in the operation of the pump and provide output indications to give the operator a diagnosis of the reason that the pump has been alarmed. These alarms include air-in-line, low battery, occlusion of the line, and infusion complete.

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Rancho Santa Fe, CA, United States of America

Jon A Jenkins