Abstract: A hand-held power injector is provided for injecting liquid, such as contrast media, into the vascular system of a mammal. The device comprises a pistol-shaped housing which encloses a battery-powdered D.C. motor for constant-rate delivery of liquid from a syringe. In a particular embodiment the hand-help power injector includes an engagement feature connecting the syringe and the power injector which prevents inadvertent activation of the power injector.

Abstract: In a dosing device of the type suitable for human implantation for delivering a liquid medicament, a piston of a pump is accelerated against a detent by energization of an electromagnetic actuation system, with the electromagnetic actuation system being controlled so that it is de-energized slightly before the piston reaches the detent, with the inertia of the piston carrying the piston against the detent to complete the piston stroke. By shortening the amount of time during which the electromagnetic actuation system is energized, energy is saved. Control of the electromagnetic actuation system is undertaken by identifying a nominal stroke time for the piston by detecting the impact of the piston against the detent, and calculating an on time for the electromagnetic actuation system which is so short that the impact of the piston against the detent can still be just barely detected.

Abstract: A method of detecting occlusions in a solution pumping system includes monitoring and analyzing pressures within the system during selected portions of a pumping cycle. The pumping system of the illustrated embodiment includes a positive displacement pump operated by a reciprocable pump piston, with analysis of pressures within the system identifying those conditions which reflect the presence of an occlusion either upstream or downstream of the positive displacement pump. A suitable signal or alarm can then be activated to alert operating personnel.

Abstract: A finger actuated pump dispenser employs a first upper hollow vertical cylinder with a first diameter and open upper and lower ends and a second lower hollow vertical cylinder with a second and smaller diameter and a closed lower end with a central opening. The lower end of the first cylinder is joined to an open upper end of the second cylinder. The inner wall of the second cylinder has a horizontal annular recess. A first vertical hollow piston has openings in top and bottom ends and extends slidably above and within the cylinders. The first piston has an enlargement intermediate upper and lower ends peripherally engaging and defining a first unbroken seal with the inner surface of the first cylinder. The first piston has a lower section extending downward from the enlargement to its lower end, the lower section having an outer diameter slightly less than the diameter of the second cylinder.

Abstract: A high pressure liquid dispenser for the delivering preferable sterile liquid with high pressure to a catheter. The dispenser includes a flexible or weak wall storage container in which the liquid to be dispensed is stored and a conduit from the front end wall of that container for dispensing liquid to a catheter. A pressure container around the storage container is stiff enough to take up the pressure of the liquid and the deformation of the storage container, so that the pressure of the liquid elevated by the pump piston may be substantially greater than without the protective pressure container around the storage container. A fluid actuated drive acts on the pump piston. The piston of the fluid actuated drive and the pump piston are respectively so shaped as to provide a pressure boost for producing higher pressure in the liquid in the storage container to produce the jet.

Abstract: A syringe pump is disclosed, having a housing, a motor driven pusher for pushing the plunger of a syringe and various transducers to determine error conditions in the placement of the syringe in the syringe pump, the pushing force of the pusher on the syringe and the engagement of the pusher drive mechanism. The syringe pump is provided with a clamp for holding the syringe in place and a device for preventing fluid from being siphoned out of the syringe. There is also a device for engaging and disengaging the motor drive mechanism. A position sensor senses the position of the syringe plunger in the barrel. A display graphically represents the syringe. Indicia are provided on the display to alert the user of conditions in the mechanism for holding the syringe in place, antisiphon device, the syringe drive engagement mechanism and the position of the plunger in the barrel.

Abstract: A syringe pump is disclosed in which the pressure in the syringe is monitored. The syringe pump includes a force detector which detects the force on the plunger of the syringe. The force on the plunger of the syringe is converted into a force by means of an algorithm which is independent of the cross-sectional area of the syringe. The algorithm calculates the pressure by subtracting a predetermined frictional force from the measurement force and multiplying the result by a calibration pressure divided by the difference between a calibration force and the predetermined frictional force.

Abstract: A central housing includes a coaxially reciprocatable screw member operative through a selectively actuated drive motor to effect reciprocation of the screw within the housing. The screw member includes a piston mounted at a forward distal end thereof mounting a flexible bag therewithin, wherein the bag directs suction from a forwardly coaxially mounted nozzle into the bag.

Abstract: A combination comprising a syringe, an adaptor, a check valve, and associated connectors for an intravenous infuser for patient-controlled analgesia. The infuser comprises a cradle adapted to receive an annular or disc-shaped element fitting into the cradle and a switch adapted to disable the infuser unless such an element is fitted into the cradle. The syringe comprises a vial, a plunger arranged within the vial for relative movement of the plunger and the vial, a tubular needle extending through an axial hole of the plunger, and a flange mounted around the needle and spaced from the plunger but too small to fit into the cradle. An adaptor having an outer rim adapted to fit over the flange and into the cradle and a check valve mounted operatively in the adaptor are connected by tubular connectors to the flange. The check valve allows an infusible liquid to flow from a chamber within the vial, through the tubular needle, and through the check valve, but not oppositely.

Abstract: An improved infusion pump is provided for controlled delivery of medication from a syringe to a patient, wherein a pump housing includes a syringe chamber and associated lock members for receiving and supporting the syringe in one of two different positions. The syringe includes a medication-containing barrel connected to a luer fitting at a nose end thereof by a luer neck of reduced cross sectional size. In one position, the syringe seats into the chamber with the luer neck protruding through an outlet port of mating size and with the luer fitting disposed outside the housing, such that the housing defines a lock member engaged axially between the syringe barrel and luer fitting to secure the barrel against axial displacement. In another position, a retainer key is adapted for installation into the syringe chamber at a position spaced inboard from the outlet port and defines an alternative lock member for axially securing the syringe with the luer fitting disposed inside the housing.

Abstract: A device for withdrawing body fluids such as blood, urine and tissue fluid includes a withdrawal unit, a suction unit, and a storage system receiving the body fluid between the withdrawal unit and the suction unit, the storage system being divided into separate areas holding the fluid fractions gathered at given intervals and permitting the individual fluid fractions to be identified with regard to their time of withdrawal. In this way tests requiring repeated sampling at short intervals are made easier for doctor and patient.

Abstract: The invention is a disposable, positive-displacement piston pump, having a polycarbonate body, a piston, an inlet valve, and an outlet valve. The outlet valve is connected to an exit chamber, which is separated from the exit valve by an elastomeric membrane. The elastomeric membrane encloses an accumulation chamber which is filled with a fluid such as air under atmospheric pressure. Pulsations in outlet pressure caused by stroking of the piston are dampened by the flexing action of the elastomeric membrane, compressing the fluid within the accumulator chamber. The throw out of the pump is pressure-dampened and is of sufficient pressure to flow through very low-profile angioplasty catheters having perfusion lumens extending therethrough. The combination of the pump with a very low-profile balloon angioplasty catheter allows access of the catheter to a constricted passage with the ability to pump a sufficient volume of blood through such a low-profile catheter during balloon inflations.

Abstract: Apparatus for introducing fluids into, and withdrawing fluids from, a hollow organ of the body, in particular a galibladder, for conducting litholysis, comprises a piston-type injection device having a multi-directional valve and which can be removably inserted into an operating mechanism. The injection device has a chamber located in front of its piston and serving as a settling chamber for a mixture of organ secretion and stone sludge removed with the solvent from the hollow organ. The valve is for the sequential connection of the pressure chamber to the hollow organ, to a tank for the solvent, and to a receiving vessel for fluid drawn off.

Abstract: An automatic syringe drive assembly and disposable heat exchanger cassette are used in combination to provide an improved thermodilution technique and apparatus. The automatic syringe drive assembly includes replaceable connecting rods on a slider crank mechanism which permit easy and accurate adjustment of the syringe injection volume. The drive assembly supports as insulated syringe for use in making the injection. The heat exchanger cassette includes a heat transfer plate and a thermoformed plastic labyrinth adhesively connected and used in combination with a thermoelectric chiller to provide a cold bolus of injectate.

Abstract: A dosing device of the type which can be implanted in a patient to control injection of liquids from a reservoir into the patient has an electrically controllable piston pump and a circuit responsible for controlling and monitoring the operation of the pump. The circuit includes a unit for acquiring a chronological curve representative of the piston motion, and electrical signals proportional thereto are obtained. These signals are supplied to control elements which compare these signals to prescribed rated values, and generate control and alarm signals given deviations of the incoming signals from the rated values.

Abstract: A unitary piston cap and boot seal for use in a medication infustion system is disclosed which is mounted on a rigid piston contained in a cylinder disposed in a cassette. The piston cap and boot seal, which are made of a flexible, elastomeric material, effectively both form the pumping element disposed in the cylinder, and prevent contamination of the pump through use of a rolling seal. The device may be sterilized by gas, since a tortuous path affording passage to gas is included in the retaining skirt mounted around the outer diameter of the pump cylinder.

Abstract: An infusion pump for administering fluid from a fluid source to a patient comprises a base member having an electric motor for driving a fluid pump housed within a cassette detachably mountable on the base and connectable to the motor. The cassette houses a reciprocative piston and cylinder assembly which both pumps fluid to the patient while simultaneously drawing fluid from the fluid source so as to maintain a continuous flow rate of fluid to the patient. The cassette also houses deformably closable pairs of tubes connecting each of the pump's two fluid chambers to the cassette inlet and outlet respectively to provide the necessary valving to produce continuous flow in cooperation with the reciprocative piston and cylinder assembly.

Abstract: A silent, high torque, impulse actuator system for low average power devices. The system incorporates a typical small three pole D.C. motor which has been modified to allow quick electrical conversion, with unipolar switching circuitry, from conventional rotation, to silent magnetic braking at a stop position; and then to a normally OFF condition.The high efficiency of this intermittent drive system is enhanced by the unique combination of being normally off between actuations; the high efficiency of the D.C. motor during start conditions; and the use of a round cam to provide a cosine power stroke that utilizes the inertia of the motor rotor to maximum mechanical advantage.

Abstract: A reciprocating pump suitable for use in an implantable medication dosage device has a piston movable in a chamber connected to a medication reservoir, the chamber having an output closable by a check valve. The check valve includes a movable element which is acted upon by a biasing system to urge the moveable element in a direction to close the check valve. The moveable element has a sealing surface against which an end face of the piston presses with tight adjacency as the piston moves to an extreme position during its output stroke.

Abstract: A pump control system is described in which the pumping mechanism causes corresponding movement of a pair of capacitor plates. The plates are energized by an a.c. signal, and the signal produced by the plates is amplitude detected, with the amplitude modulation representing pumping force. The pumping force is converted to pumping pressure. The pumping pressure peak during pumping and the pressure minimum during filling are detected to determine the portion of a pumping cycle required to make the transition between these two pressure levels. The difference between the two pressure levels divided by the transition portion of the pumping cycle gives a measure of the compliance of the pump chamber. The ratio of the compliance measure to the total cycle, when multiplied by the nominal chamber volume, gives a measure of unpumped volume, which is subtracted from the nominal volume to give the volume actually pumped during a pump cycle.

Abstract: Air entrained in a pumped liquid is released from a pumping chamber operated by a single piston and having an outlet passage controlled by a back-seating valve biased closed by a spring, when the piston near the end of its compression stroke causes positive mechanical engagement to open the outlet valve.

Abstract: An infusion pump for administering fluid from a fluid source to a patient comprises a base member having an electric motor for driving a fluid pump housed within a cassette detachably mountable on the base and connectable to the motor. The cassette houses a reciprocative piston and cylinder assembly which both pumps fluid to the patient while simultaneously drawing fluid from the fluid source so as to maintain a continuous flow rate of fluid to the patient. The cassette also houses deformably closable pairs of tubes connecting each of the pump's two fluid chambers to the cassette inlet and outlet respectively to provide the necessary valving to produce continuous flow in cooperation with the reciprocative piston and cylinder assembly.

Abstract: A device for detecting partial restriction in a fluid line connecting a fluid source with an IV infusion pump comprises a gauge mounted on the pump and operatively associated with the line to determine fluid pressure therein. The pump also comprises a peristable finger to conditionally occlude the line and a miroprocessor, upon occlusion of the line, to establish fluid pressure parameters within which the indication is that there is no partial restriction in the line. The pump also uses the microprocessor to compare actual pressure measured by the gauge during an occlusion with the established parameters to determine whether pump operation is to be continued.

Abstract: A reciprocating pump having a fluid assembly having a fluid wing at its input side encompassing an admission line and an admission chamber. A moveable valve part of, for example, a magnetizable material is arranged in the admission chamber. A component part, for example a permanent magnet, which attracts the valve part against a valve seal is situated outside of the fluid wing. The valve part and the component part together form a magnetic spring system. An advantage of this arrangement is an extremely small dead spacing inside the fluid wing. Resulting therefrom is that gas bubbles can also be conveyed with great reliability. Also harmful interaction between the conveyed medication and the component part such as, for example, corrosion of the component part or conversions of the medication influenced by the component part, cannot occur.

Abstract: The present invention is directed to an improved cassette for use in an intravenous infusion pump. The cassette of the present invention includes a cassette body which is capable of being removably secured within a volumetric pump. The cassette body has a volumetric chamber of predetermined volume which is placed in communication with an inlet and an outlet. The volumetric cassette includes an inlet corridor through which fluid may flow into the cassette. The inlet corridor in turn flows into a central corridor which leads directly to the volumetric chamber. The cassette also includes an outlet corridor which is also in communication with the central corridor and, in turn, the volumetric chamber. Fluid will, therefore, exit the volumetric chamber through the outlet corridor by way of the central corridor. The outlet corridor is then connected to the patient infusion line. The cassette of the present invention also includes a plunger which reciprocates within the interior of the volumetric chamber.

Abstract: A back pressure sensor comprising a flexible beam having a pivot end with a pivot pin and a drive connector end with a means for engaging a pump drive. A pump actuator is connected to the flexible beam at a position intermediate the ends and connects with a positive displacement pumping member. A sensor beam is attached to the flexible beam at a connecting point spaced from said pivot end. A first capacitor plate is mounted on the flexible beam at a point which is spaced from the connecting point. A second capacitor plate is mounted on the sensor beam in a position facing and spaced apart from the first capacitor plate at a distance therefrom which permits formation of a capacitance coupling therebetween.

Abstract: A back pressure sensor for a positive displacement pump comprises at least one flexible beam having a pivot end and a drive connector end, and a pump actuator mounted between the pivot end and the drive connector end. The pump actuator connects with a positive displacement member of a pump. At least one sensor beam is connected to the flexible beam at a mounting position between the distal end and vibration damping end thereof. A first capacitor plate is mounted on the flexible beam at a position adjacent to the pivot end thereof, and a second capacitor plate is mounted adjacent the distal end of the sensor beam in a position facing the first capacitor plate at a distance which permits a capacitance coupling between the capacitor plates. A vibration damping mass is secured to the vibration damping end of the sensor beam for damping drive motion vibrations in the sensor beam.

Abstract: A detector for determining when an occlusion has occurred in the fluid line of an IV administration set comprises means associated with an IV infusion pump to determine the resistive force exerted by fluid in the line against the pumping mechanism of the pump. The detector includes a flexible beam which is mounted between the plunger and the activator of the pumping mechanism and which bends proportionately to the magnitude of the resistive force. A strain gauge attached to the beam activates an alarm which stops the IV pump when flexure of the beam indicates an occlusion in the line has occurred.

Abstract: Disclosed is an implantable device for the injection of fluid into a patient's body. The device includes a non-invasive external part which magnetically cooperates with the implanted portion through a magnetic field. The device is entirely mechanical and is capable of delivering both a continuous dose of fluid as well as instantaneous dose of fluid. The mechanism comprises a fluid reservoir, a catheter, an elastic means, a regulating means, a magnetic drive means, a gear transmission means and a flow adjustment means.

Abstract: An irrigation device for injecting and withdrawing liquid from a body cavity, comprising a first chamber separated into two compartments by a partition provided with a one-way valve, wherein one compartment is operatively connected to a rolling diaphragm in combination with a piston member and the other compartment provided with a nozzle adapted to be coupled to a catheter already inserted in the body cavity.A second chamber is removably attached to the first chamber with a gasket and filter member therebetween. With the device filled with irrigating liquid, manually pushing the piston member into the operatively connected compartment forces liquid through the one-way valve into the other compartment and through the nozzle and catheter into the body cavity.

Abstract: A pump for oscillating a fluid into and out from a body area. The pump forms a fluid chamber for holding the fluid, and comprises a piston for forcing fluid outward from the fluid chamber and into the body, and for drawing fluid inward from the body and into the fluid chamber. A motor is connected to the piston, and a control circuit is connected to the motor to control movement of the piston. The control circuit has a first state actuating the motor to force the fluid into the body, and a second state actuating the motor to draw the fluid from the body, and the control circuit may be adjusted to vary the rates at which fluid is forced into and drawn from the body.

Abstract: A muscle powered liquid dispensing insert is provided for use with an implanted anchor having a hollow anchor sleeve extending into the subcutaneous fascia of a region behind an animal's ear. The insert includes one or more balloon-like reservoirs, each containing a drug or other medicant in substantially liquid form. Each reservoir means additionally provides effective means for anchoring the insert in the animal. A pump assembly draws the medicant(s) from the reservoir(s), and dispenses such to the animal. The pump assembly has a toroidal pump body defining a pump chamber and including a flexible impermeable pump diaphragm. The pump chamber communicates through inlet check valve means with each of the reservoirs, and through outlet check valve means with the tissue of the animal. The outlet check valve means operate at a higher activation pressure than the inlet check valve means. A piston powered solely by the animal's muscle and tissue operates the pump diaphragm.

Abstract: A pump wherein an armature (64) is reciprocated between an electromagnetic core (54) and a housing (48). A diaphragm (68) is responsive to movement of the armature (64) and cooperates with a body (10) to form a pumping chamber (80). Expansion of the pumping chamber (80) by spring (66) draws fluid through a valve (20) at a slow rate. Contraction of the pumping chamber (80) by electromagnetic attraction of armature (64) to core (54) expels fluid through valve (42).

Abstract: A method and apparatus for aspirating secreted fluids from a wound is disclosed which involves the placement of a drain into a wound via the tissue adjacent the wound. After the wound is closed, a secretion aspiration and collection device, which is connected to the drain via a tube, is placed into operation. The device is designed to have a suction effect controlled between a minimum value and a maximum value according to the quantity of secreted fluid to be aspirated. This is achieved by one or more sensors which control a tube pump. When a second sensor is used, the pump will not be shut off by a passing air bubble in the fluid. A sleeve may also be provided to facilitate introduction of the drain into the wound. Additionally, a needle may be detachably connected to the sleeve to aid the insertion of the sleeve.

Abstract: A method for dissolving a solidified mass in vivo, and apparatus for oscillating a fluid into and out from a body area. The method comprises introducing a dissolving agent into a body area, and oscillating an agitating fluid into and out from that body area to stir the dissolving agent therein. Body fluids withdrawn from the body area with the agitating fluid are separated therefrom, and the separated agitating fluid is reintroduced into the body area to further stir the dissolving agent. The apparatus comprises a pump to force fluid into and to draw the fluid from a body area, a trap for collecting body fluids aspirated from the body area, and fluid lines to connect the pump to the trap and the trap to the body area.

Abstract: A device for evacuating body fluids under sub-atmospheric pressure is disclosed using a suction device in which a constant force means is utilized to create substantially constant vacuum in a chamber of the suction device, and the device progressively fills with fluid drawn thereinto through a catheter or the like. The device includes an elongated cylindrical chamber with a movable piston therein and with peripheral seal means on the side wall of the piston to seal against the inner wall of the elongated cylindrical chamber to provide a seal thereat. An intake means to the cylindrical chamber is provided with a check valve therein which provides for only a unidirectional flow of fluid through the intake means.

Abstract: An IV filter and pump assembly having first and second bodies secured into a unitary assembly. The first and second bodies provide a chamber. One of the bodies has an opening therein in communication with said chamber and an inlet port therein. The other of the bodies has an outport therein. The inlet and outlet ports are in communication with the chamber. An inlet valve controls the flow of liquid through the inlet port and an outlet valve controls the flow of liquid through the outlet port. A hydrophobic filter is carried by the unitary assembly and is in communication with the upper portion of said chamber for venting to ambient small quantities of air in said chamber. An actuator supplies a pumping action to the liquid in the chamber so that liquid is caused to be moved out of the chamber through the outlet valve and into the chamber through the inlet valve.

Abstract: A fluid infusion pump driver device for pumping fluid from the chamber of a disposable cassette. The pump driver includes a reciprocatable plunger which is driven by a stepping motor. The motor and plunger are coupled through a universal joint which provides a threaded connection translating the incremental angular movements of the motor into incremental linear movements of the plunger, and the plunger is coupled directly to the frame through a flexible leaf spring to prevent wear in the threaded connection from generating undue noise or creating accuracy problems.

Abstract: An implantable, anti-reflux, fluid displacement peritoneovenous shunt system. The system includes a double chambered multi-micro-orifice ascites collection device, a magnetically driven pump, and an anti-reflux, anti-backdiffusion, non-thrombogenic catheter tip, all connected by flexible tubing. The shunt is used to transfer fluid from the peritoneum to the cardiovascular system to prevent accumulation of fluid within the peritoneal cavity. The magnetically operated pump may be of either the reciprocating diaphragm or piston type or it may be a rotary driven bellows displacement pump.

Abstract: A gravity flow cassette for use with an I.V. infusion pump has a fluid inlet, a fluid outlet and a pump chamber with associated pump piston. A valve body having an annular groove and a partial groove parallel thereto is slidably disposed in the cassette for reciprocal movement between a first position and a second position. Engagement of the cassette with the pump firmly holds the valve body in the first position wherein the annular groove is sealed and the valve body can be rotated to alternately provide fluid communication through the partial groove between the inlet and the pump chamber or between the pump chamber and the outlet. Upon disengagement of the cassette from the pump, the valve body can be moved into the second position to seal the partial groove and provide for simultaneous fluid communication through the annular groove between the input, the output and the pump chamber.

Abstract: A hose assembly for use to regulate flow from a dispensing device that provides a generally constant pressure on a liquid to be dispersed. The hose assembly includes a length of capillary tubing through which the liquid must pass as it is dispersed which has a length of at least 45 centimeters and a volume of less than about 0.25 cubic centimeters so that the assembly can provide a slow steady predetermined flow rate while containing a small amount of the liquid being dispensed.

Abstract: An dispenser characterized by provision for use of a replaceable needle and a prefilled cartridge.The dispenser comprises an elongated body separable into two body sections, with the front end section adapted to contain a prefilled cartridge and with provision at the front end for mounting a needle removably thereon.The back end section contains the operating mechanism shown by FIG. 10 to convert the longitudinal movement of a pushable element into unidirectionally rotary movement, then into longitudinal movement of a piston rod that acts to expel fluid through the needle.A multipurpose cap is protective of the needle end when mounted on the front end, and is an operating member when mounted on the rear end, as is illustrated by FIGS. 1 and 2.

Abstract: In a mouth and tooth spray apparatus, a handle is mounted in a mounting such that the handle can be pivoted out of an upright position about an axis into a horizontal position parallel to the long wall of the appliance base of the mouth and tooth spray apparatus. This design makes it possible to push the water container, as a cover, over the appliance base from the narrow side of the appliance base.

Abstract: A medical suction device is provided in which a constant force means is utilized to create substantially constant vacuum in a chamber of the suction device, as the device progressively fills with fluid being drawn thereinto from a catheter or the like. The fluid drawn into the chamber of the suction device is selectively dischargeable therefrom into a discardable receptacle that is attached through a drain valve to the chamber. Multiple, folded, discardable receptacles, each connected through a separate drain valve, are connected to the storage chamber of the suction device. The arrangement operates to effect isolation against transmittal of infection. The multiple discardable receptacles accommodate a high volume of discardable material, while the suction device apparatus is of low bulk and is provided with means to prevent exposing the suction chamber to atmosphere, and to atmosphere-borne contamination.

Abstract: An infusion pump system is described containing a valved cassette which is used as a pumping chamber for conducting fluid from an upstream portion to a downstream portion of the system. The removable cassette contains magnetically biased valves at both ends. Externally mounted magnets bias the valves within the cassette to provide an opening of the inlet valve and closing of the output valve during the fill cycle and closing of the inlet valve and opening of the outlet valve during the pump cycle. Free flow of infusion fluid is allowed when the valved cassette is removed from the pump mounting member which houses the actuating magnets and the reciprocating actuator for the pumping chamber.

Abstract: A disposable syringe cartridge including a molded plastic cylinder having an open end and a closed end with inlet and outlet nipples integrally formed in the closed end, and a plastic piston head slidably received in the open end of the cylinder and pivotably connected to a plastic piston rod. The piston head utilizes a quad-type sealing ring providing a pair of adjacent sealing surfaces with the cylinder, and includes a square expansion flange rounded at each of its corners to conform in shape to the cylinder, with a rubber annular sealing boot extending between the open end of the syringe cylinder and the piston rod. A flange formed on the outer circumferential edge of the sealing boot is received over the open end of the cylinder and is captured by an annular cap that is ultrasonically welded to the cylinder, while a bead formed on the inner circumferential edge of the sealing boot is received in a groove defined by a pair of adjacent annular flanges formed on the piston rod.

Abstract: An implantable microinfusion pump system for dispensing medication at a prescribed infusion rate within the human body includes a hermetically sealed housing in which a power source and circuitry for actuating the pump are contained. A permanently magnetized piston is mounted for reciprocative fill and pump strokes within a pump chamber defined by a pump body member which extends between parallel-spaced walls of the housing. The body member communicates at one end with an expandable medicament reservoir adjacent one wall of the housing, and at the other end with a catheter for conveying medicament to the body. A two stage valve arrangement causes medicament to enter the pump chamber during fill strokes of short duration and to be dispensed from the pump chamber at the prescribed infusion rate during longer duration pump strokes.

Abstract: An integral valve and pumping unit is provided for infusing medication into the body which employs only one moving part. This pumping unit is connected to the medication supply reservoir through a first flow restriction device which has no moving parts but has directional flow characteristics so that liquid medication can flow readily from the reservoir to the pumping unit but flow from the pumping unit to the reservoir encounters a relatively high resistance. A second flow restriction device is connected between the pumping unit and the outlet catheter which is employed to infuse medication into the body, this second flow restriction device likewise having no moving parts and offering relatively little resistance to liquid flow from the pumping unit to the catheter while having relatively high resistance to flow in the opposite direction.

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.