Infusion Pump

Glossary

Pressure: The pressure is a physical magnitude that allow measure the force in perpendicular direction of area unit. The pressure its represented by P = F/A .

Sensors: Its an instrument that is capable of measure a magnitude and may vary its value when the magnitude measured  have a change.

Volume: Its a magnitude that represent the occupied space for any object.

Infusion: Its a verb that describes the action of transmit some medicine from the package to patient body.


Infusion Pump

The infusion pump is a device that provides by controlled way a determined medicine intravenous. Currently we can find four kinds of infusion pumps, for example, peristaltic pump, syringe pump, elastomeric pump and implantable pumps.

Peristaltic pump

The peristaltic pump have 2 ways to provide de medicine, rotatory peristaltic pump or lineal peristaltic pump.

Rotatory pump: The rotatory system have a circular capsule with a variable number of rollers (called fingers) that press the pipe whereby the medicine cross, the rollers are in charge of push the liquid in a specific rate.

Figure1. Peristaltic pump rotatory system

Lineal pump: The lineal system have a rectangular capsule with many rollers inside, that  rollers are in charge of press the pipe vertically, at the time of some rollers are pressing the pipe others are leaving the pressure to allow the liquid movement.

Figure2. Peristaltic pump with lineal system

Syringe pump

The syringe pump allow provide small amounts of medicine, from 1 ml to 60 ml.This device use a syringe where the medicine is placed and the system push the plunger to nudge the medicine.

Figure3.Syringe pump

Design of a infusion pump

To design a infusion pump we had to use a 12 DCV motor (see the figure4), with an adaptation of 3 rollers inside.
To control the motor we used a different pwm values, to find the correctly values we had to do a characterization (see the figure5).

Figure4. 12 DCV motor with peristaltic adaption.

Figure5. Characterization table of DC motor

Then we made a graph using flow and PWM, to obtain the lineal regression and the linear equation, the equation obtained is y = 0,0043x - 0,1042,(see the figure6).

Figure6. Linear regression 

We used a simple circuit with a H-bridge (l293d) to control the motor

Figure7. L293D H-bridge circuit.

To download the arduino code  CLIC HERE