Designing

 

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Last week we came up with a design criteria and it was evaluated using pairwise comparison chart. 

We brainstormed 8 designs of protecting compressor from dust which were evaluated using Pugh scoring matrix and the selected design criteria.

Three designs were selected to be tested then implemented if they meet the desired requirement:

·         Improved external filter

·         Filter box to be attached outside the concentrator

·         Attach a positive pressure fan

A 240v Ac positive pressure fan was connected to the concentrator and tested to determine if it can control the entry of air into the concentrator thereby reducing entry of dust.  So far the results are positive.

Shown above are some of the filtering materials which were bought last week from Cash Build and Shoprite. They are to be used to improve external filter and to build a filter box with the aim of controlling entry of dust into the concentrator.

We designed an air flow test experiment consisting of a fan, two cylindrical plates, Arduino, pressure sensor, connecting pipes, in order to test the porosity of each filter. Each filtering material was placed in between the cylindrical plates to test how much air it could allow to flow. The reading of pressure was printed on the computer after the fan was switched on. The control filter (black) gave a reading of 49 units (lots pf airflow), the cleaning sponge (pink and green) indicated 51 units (moderate airflow) and scotch brite (green) and filter roll allowed 52 units (moderate airflow). 

 

Hospital visits

We visited Thyolo ,Mulanje, Zomba and Chiradzulu district hospitals located in the southern region of Malawi. The purpose for this trip was to investigate the reasons why compressors in oxygen concentrators break down and find out ways of protecting concentrators from dust.

 

Common types of oxygen concentrators:

  • Devilbliss
  • New life

Usually these concentrators work for 24 hours everyday.

The concentrators have filters to trap dust and bacteria.

  • Two air filters which are reusable
  • Bacteria filters cannot be cleaned or reused.

Common problems in oxygen concentrators

  • Over heating of motor
  • Bursting out of cables.
  • Wearing out of seal and cups in the compressor due to friction.

Ways of protecting concentrators from dust

  • Clean air filters weekly
  • Mop floor everyday.