Peristaltic Pump

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Introduction

A peristaltic pump, also commonly known as a roller pump, is a type of positive displacement pump used for pumping a variety of fluids. The fluid is contained within a flexible tube fitted inside a circular pump casing (though linear peristaltic pumps have been made). A rotor with a number of “rollers”, “shoes”, “wipers”, or “lobes” attached to the external circumference of the rotor compresses the flexible tube. As the rotor turns, the part of the tube under compression is pinched closed (or “occludes”) thus forcing the fluid to be pumped to move through the tube. Additionally, as the tube opens to its natural state after the passing of the cam (“restitution” or “resilience”) fluid flow is induced to the pump. This process is called peristalsis and is used in many biological systems such as the gastrointestinal tract. Typically, there will be two or more rollers, or wipers, occluding the tube, trapping between them a body of fluid. The body of fluid is then transported, at ambient pressure, toward the pump outlet. Peristaltic pumps may run continuously, or they may be indexed through partial revolutions to deliver smaller amounts of fluid

Source Wikipedia.

The core of this project is a 3D printed part, which is a peristaltic pump controlled Arduino.

The user can control the pump to :

  1. pump a liquid continuously
  2. pump a defined quantity separated by interval, for this the pump offers three type of programs:
    1. fixed quantity: repeat a number of times pumping a fixed quantity and wait a defined time
      • example: repeat = 3 times, quantity = 6ml, interval = 9 sec
    2. incremental quantity: repeat a number of times pumping an incremental quantity and wait a defined time
      • example: repeat = 6 times, starting quantity = 6ml, increment by = 3ml, interval = 9 sec ( This option is not yet complete, but I will update it each time I make some advance.)
    1. and program from file: pump 18 different quantities, with a fixed interval between each quantity, the quantities can be random as: dose1 = 10ml, dose2 = 0.1ml…dose17 = 8ml, dose18 = 0ml
  • The pump uses text files “.txt” stored to an SD card, are easy to edit on your computer or by a tactile button via Arduino.
  • the user can calibrate and configure the pump by entering a setting menu.
  • the smallest quantity that can be pumped is 0.1ml
  • about 200 ml/min can be pumped
  • the direction can be changed
  • A default speed and direction can be set and stored to the SD card for continuous pumping so the user doesn’t need to press hundreds of times each time the pump is started.

The pump have 3 sections that offers different informations for the user:

  1. top section: the path(or breadcrumbs), which is a text showing the navigation tree:
    • when you enter settings and speed is selected: settings>speed
  2. right section:
    • shows the state of the pump(run/pause)
    • direction: fill/empty
    • control: local/remote(a place holder for future update, not yet available)
  3. foot section: guides the user with different messages about actions needed, successful changes, selections, errors..etc

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