Modifying Hospital Sterilization Boiler for Countries Overseas

Justin Albrethsen1, Jacob Gorton1, James Gruss2, Michael Kibbe1, Jennifer Moran2

Marco Orlando2, Thomas Roache3

Mechanical Engineering1, Software Engineering2, Industrial Engineering3

Problem Statement

The stakeholder, Christian Hospitals Overseas

Secure Equipment Needs (CHOSEN), requires

a more automated steam generation system.

This system will be implement. In medical

sterilizers to be used in developing countries.

Vision Statement

To design a boiler system that will automate

both pressure and water level using minimal

electricity.

Design Requirements

Minimal electricity and technical

knowledge for operation

Capable of using variable heat sources

Constant boiler tank pressure of 80 ± 10 psi

Tank must maintain a water-to-steam ratio

of approximately 1:1

Automatic pressure regulation

Automatic water level regulation

Sight glass must have fittings greater than

NPS 1/2, have a drain greater than 1/4”, and

1” below the lowest allowable water level

must be visible (ASME)

Temperature gauge to quickly identify

internal temperature

Pressure gauge to quickly identify internal

pressure

Check valve and stop value must be present

between the water pump and boiler tank

A drain value of at least NPS 3/4 must be

present near the bottom of the tank (ASME)

Tank Schematic

Pressure Regulation Solution Regulator valve must be calibrated to stay

within pressure variance

When pressure limit is reached, valve will

open to relieve excess pressure

Steam generation will keep pressure above

lower limit

Failsafe emergency valve will open when

pressure reaches 100 psi and will stay open

until system is reset.

Water Level Maintenance Solution

Water level will be maintained through a

conductive probe apparatus, an Arduino Uno

microcontroller, and an electric pump

The pump motor will be controlled by a solid

state relay, which will be protected by a

circuit breaker

Three probes will be used: a 5V live probe, a

high level probe, and a low level probe

As water contacts a sensing probe, a circuit is

completed which sends an analog signal to

the Arduino

As water falls below the low level probe, the

pump will start; as water contacts the high

level probe, the pump will stop

Full System Diagram

Side View of Tank 1

Side View of Tank 2

Next Steps

Acknowledgements

The system has been tested and it is verified

that the regulator valve will keep the pressure

in the tank within the allowable 80 ± 10 psi

range. It was also verified that the probes

maintained the water level automatically.

Unfortunately, the failsafe emergency valve

did not open even when reaching a psi of 120.

Once this issue is resolved, CHOSEN will be

able to send these systems to developing

countries.

SEECS, Scholars of Excellence in

Engineering and Computer Science, is a

scholarship program funded by a National

Science Foundation S-STEM Award

#1153250

Pictured here is a view of the 3 water

sensing probes and their connections to

the Arduino microcontroller

Pictured here is a view of sight glass