Abstract: A servo controlled actuator for an automated liquid dispenser for dispensing reagents or diluting samples with reagent automatically in accord with a programmed local microprocessor or remote computer control. The dispenser has at least one reciprocable syringe, valving for it and a syringe actuator driven by a hybrid servo control. The actuator includes a bi-directional variable speed motor and an encoder developing a pulse train which in number is representative of the position of the syringe piston and in repetition rate is representative of piston velocity. A microprocessor controls the piston stroke from the pulse train by comparison to a memory-stored count and controls piston velocity in predetermined relation to the terminal end of piston travel.

Abstract: A control procedure for governing the incremental step operation of a pump stepping motor (74) employed in conjunction with a parenteral fluid metering device (2) is disclosed. The control procedure enables fluid to be pumped from the metering device (2) in non-pulsatile, essentially continuous fashion by suitably adjusting the stepping motor speed to compensate for the interruption of fluid flow which occurs during the refill phase (P.sub.R) of each pumping cycle (C). Adjustment of the stepping motor speed also compensates for non-linearities otherwise introduced into the fluid flow as a result of the camming mechanism (76,78) utilized to convert rotary stepping motor movement into rectilinear pumping movement.

Abstract: An extracorporeal medication infusion device provides a precise infusion rate of a liquid medication into a human or animal body. The infusion device includes a permanent portion which has a case, a battery, a programmable electronic controller, and an electromagnetic solenoid core and solenoid coil for providing an actuation force. The infusion device also includes a disposable portion which includes a reservoir filled with a liquid medication that is to be dispensed and a pump for pumping the medication from the reservoir into the user's body. The pump includes a pump chamber and a piston connected to an electromagnetic armature for altering the volume of the pump chamber in response to the actuation force.

Abstract: A disposable intravenous pump chamber assembly for an intravenous administration set which substantially reduces the problem of air bubble entrapment so that the amount of intravenous fluid delivered is effected in an accurate manner. The pump chamber assembly is specifically constructed to be utilized in conjunction with a diaphragm-type pump with external valving. The pump chamber cassette is held in the pump in a unique manner and includes a porting and fluid delivery arrangement which reduces the problem of air entrapment in the pump chamber.

Abstract: Apparatus is provided for obtaining a controlled flow of fluid from a source to a patient. The apparatus includes a plunger movable vertically in a chamber and made from resilient material and having a pair of vertically spaced lands. The chamber defines a recess with the lands and the plunger in the space between the lands. Lubricating fluid is disposed in the recess. Fluid such as intravenous fluid is introduced into the chamber in one reciprocal movement of the plunger and is withdrawn from the chamber in the other reciprocal movement of the plunger. A porous washer filled with lubricating fluid is disposed in contiguous relationship to a particular one of the lands for providing an auxiliary reservoir of the lubricating fluid. Such washer may be contiguous to the lower one of the two (2) lands.

Abstract: An extracorporeal medication infusion device provides a precise infusion rate of a liquid medication into a human or animal body. The infusion device includes a permanent portion which has a case, a battery, a programmable electronic controller, and an electromagnetic solenoid core and solenoid coil for providing an actuation force. The infusion device also includes a disposable portion which includes a reservoir filled with a liquid medication that is to be dispensed and a pump for pumping the medication from the reservoir into the user's body. The pump includes a pump chamber and a piston connected to an electromagnetic armature for altering the volume of the pump chamber in response to the actuation force.

Abstract: The pump has a chamber in which a piston reciprocates to pump a liquid. The piston is moved by having secured thereto the armature of at least one electromagnet (preferably two). The coil of the electromagnet is suitably external of the pump casing. A control circuit pulses the electromagnet at a predetermined rate to provide a predetermined periodic output.In a preferred form, the pump is mounted together with a liquid reservoir on a printed circuit board, and the unit is encapsulated for implantation in the human body to infuse a liquid medicine at a controlled rate into the bloodstream.

Abstract: Metering apparatus for controlling the flow of fluid through a fluid infusion system at an operator-designated rate includes a single-use cassette having a syringe-type pump in the flow system. The cassette is removably mounted on actuator apparatus which drives the syringe plunger through alternate fill and pump modes to advance fluid through the system. To provide compensation for the lack of flow in the system during fill strokes, the plunger is advanced at a higher compensation rate for first and second portions of the pump stroke immediately preceding and immediately following each fill stroke, with the pump stroke advancing at the designated rate therebetween. This results in an average flow rate which corresponds to the designated rate. By making the first and second compensations of equal duration, the effect of the fill cycles on the regularity of the average flow rate is minimized.

Abstract: 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.

Abstract: A disposable intravenous pump chamber cassette for an intravenous administration set which is specifically fabricated for use with the administration of blood. The pump chamber is specifically constructed to be utilized in conjunction with an intravenous pump having a driver to activate a diaphragm member and includes an improved outlet valve member having an outwardly extending lateral wall surface to direct the blood away from the biasing mechanism for the outlet valve member to thereby substantially reduce hemolysis.