2014 12-22 - functional analysis of a sterilizer (rb)

Functional analysis of a sterilizer

Renata Bertocchi

Open Source for Biomedical Engineering - OS4BME


Projecting an UVC Sterilizer:

Analysis of real needs

Analysis of physical principles

The Project

Mechanics

Electronics

Software


Lack of hygienic condition:

35.3 million people living with HIV/AIDS worldwide in 2012

1.6 million people died of AIDS-related illnesses worldwide in 2012

More than 780,000 people die every year due to the consequences of hepatitis B

Ebola: over 4,500 deaths in ten months

WHO Data


Main blood diseases vectors:

Surgical tools

Dentist tools

Podiatrist tools


“An estimated 4,100 children under the age of five die each day from diarrhea globally. Malnutrition, due to dirty water, inadequate sanitation, and hygiene, is estimated to lead to death in an additional 2,350 children under the age of five each day.”

WHO data


Water crisis caused by:

Climate change

World population growth

Bad management


Water crisis (2008)


Water crisis (2025)





The Project

Mechanics

Electronics

Software


UV radiation


UV radiation: brief history

All started in 1672 with Isaac Newton’s decomposition of light


UV radiation: brief history


UV radiation


UV radiation inactivation


UVC uses

Air sterilization (typically in cellular culture systems)

Water sterilization (aquriums and bioreactors)

Surface sterilization (surgical rooms, surgical tools)


UVC uses





The Project

Mechanics

Electronics

Software


UVC material interaction

Absorption can cause an increase of temperature which can damage material like polymers.



Polymers tend tolose their propertiesbecause thepresence ofimpurities causesphotodegradation.



Even if penetration is verynegligible (75 µm), UV

irradiation can degradewood surfaces more than

visible light.

Material containingcellulose is generally

bleached



Glass has nearly zerotransmission level

Glass solarization

Textiles generallylose their coloursexciting cromophores



Transparent material to UVC are mainly soft glass (Sodium-Barium), quartz glass, Teflon

Metal are generally UV stable, some of them have good reflective coefficient (Aluminium)


Material choice and dimensioning

Aluminium Dimensions- ρ = 70-80% - lamp size- low cost - surgical tools dimensions- low weight


Material choice and dimensioning

Aluminium

1) 2) 3)

- cheap - less processing - ready-to-use- need of processing - round angles - round angles- big quantities - big quantities - expensive


Dimensioning: 3D-modelling


blue print


3D printed parts





The Project

Mechanics

Electronics

Software


UVC LED

- power output - shape - viewing angle - cost


The lamp

- size- power- shape- useful life


Modelling the system

k = 2*10-4 m2/J



Aluminium ρ = 70-80%


Modelling the systemµController



Arduino isOpen-sourceEasy to useLow cost





The Project

Mechanics

Electronics

Software



Arduino (www.arduino.cc) usesa simple Integrated DevelopmentEnvironment (IDE) allowing allkinds of users to write programs

using a language similar to C/C++.

http://www.arduino.cc/


Finally...

We have a surface sterilization system safe and low-cost, capable of sterilize surgical tools in 1 h (30 min per part).

Sterilization: regulations & standards

Case of study: UVC sterilizer

UVC is an emerging method of sterilization and there is not a precise regulation to observe. This implies more caution and a long research for articles and footprints of who has already work on it.


About sterilization of health care products...

Over 60 ISO rules!!!


Case of study: UVC sterilizer

Radiation


Case of study: UVC sterilizer – gluing the pieces...

Choosing is fundamental- to save time in consulting- ISO rules are not free...


About water sterilization



“At sufficiently high doses, all waterborne enteric pathogens are inactivated by UV radiation.” WHO



Problems:- filtration- flux- UVC interaction with glass


References:

1. Many data from www.who.inc

2. Scientific America, some articles about water crisis

3. Ultraviolet Germicidal Irradiation Handbook - UVGI for Air and Surface Disinfection. Kowalski, Wladyslaw

4. www.arduino.cc

5. www.wikipedia.org

6. Philips lamp catalogue and Omron µSwitch catalogue

http://www.who.inc/

http://www.arduino.cc/

http://www.wikipedia.org/


Thank you for your Thank you for your attention!attention!

2014 12-22 - functional analysis of a sterilizer (rb)

Engineering

Transcript of 2014 12-22 - functional analysis of a sterilizer (rb)