Smiths Group Plc

Robert James Tribe

Anthony Richard Cobb

Chris Pickles

A syringe pump has a motor rotating a leadscrew, which drives a plunger head retainer to push a plunger along the barrel of a syringe so as to dispense medication to a patient. A force sensor in the head retainer measures the force on the plunger to detect when there is an occlusion restricting flow of medication. When an excess force is detected an alarm is generated and the motor is reversed to reduce the force to about 10% of that at which the occlusion is detected. The occlusion can be removed with a reduced risk of a bolus of medication being dispensed after which the user restarts the pump so that the plunger is driven normally.

Syringe pumps

A syringe pump has a motor rotating a leadscrew to drive a plunger head actuator along it. The head actuator engages the plunger of a syringe and moves the plunger along the syringe barrel to dispense medication. An optical encoder mounted on the leadscrew is rotated by the motor to produce a pulse output. A control unit times the interval between the pulses and compares these timings with a stored value representative of a predetermined multiple of the minimum time. If the head actuator is obstructed, the speed of rotation of the motor is slowed and the time interval between pulses rises. When this exceeds the stored value, the control unit stops the drive to the head actuator and generates an alarm.

A syringe pump has an arm swung against the barrel of the syringe. The arm is coupled to a strip mask having a row of transparent apertures of differing length. The mask extends above a CCD array of sensing elements and below a concave mirror, which produces a collimated beam of radiation on the mask from an LED. The length of sensing elements exposed to radiation through an aperture in the mask gives an approximate indication of barrel size; the position of an edge of the aperture gives an accurate indication. The pump compares the barrel size with information relating size to syringe type and produces an indication of syringe type on a display.

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Loughton, United Kingdom

Robert James Tribe