UWE Bristol Engineering showcase 2015

Jack Bottomley
BEng – Electronic Engineering
Project Supervisor
Nigel Gunton
Solid State PCB Valve Design
Aircraft need the ability to control the flow of liquids around the entire airframe; examples include re-directing or stopping the flow of
fuel and air in the air conditioning as well as controlling the amount of fuel being provided to the engines. Until now, mechanical valves
have been implemented to do these processes, however as technology develops in the aviation industry, there is becoming a need for
smaller, lighter and more reliable solutions.
Printed circuit boards are commonly used in a variety of applications due to their versatile functionality; however until now they have
never been used to control a solid state valve. Opening a valve that controls the flow of a liquid between two chambers, using only a
PCB is a new concept, which has not yet been developed. This method has the potential to replace the mechanical alternative if the
concept is feasible.
Design
Once all the possible ideas for the PCB valve had been compared and selected the design
stage was completed. Auto cad was used to design the physical parts and they were sent
off to be manufactured for a strong , high temperature material called polyimide.
A reactive filler was designed to hold the a plug into the board, which would deform and
open the valve once heated to 140◦c via the PCB tracks. Calculations were made for track
width and circuit designs were made so that the system would work as required once the
PCB was powered up from a power supply.
Research
Initial research into possible solutions was completed. The
materials and set-up for the PCB and valve were chosen after
looking into different options. Materials such as Zirconium
tungstate (Zr(WO 4 ) 2 ) which display characteristics of
negative thermal expansion ,were considered but rejected
due to high cost and difficulty of manufacturing them to
required specification
Build & Test
After all the separate parts of the system had been manufactured, they could be
brought together and integrated ready for testing and verification. A circuit breaker
was used for circuit protection and added safety. A weight was applied to the PCB
valve to represent the force being applied to the valve from water trying to pass
through. The valve was then opened on command, allowing the weight to fall,
demonstrating that the valve could be used to open and control the flow of water.
Project summary
The project was to research then design and
build a prototype PCB board that has the
ability to open a valve ,allowing the flow of a
liquid to be controlled.
This project was initiated so that a modern
solution could be developed with a view of
replacing a mechanical valve that is currently
used for this application.
Project Objectives
The objective of this project, was to prove a
conceptual idea that a valve can be controlled
by a PCB using minimal components. The aim
was to design and build a prototype that
could be verified against the requirements,
proving that there are alternative options to
using a relatively unreliable mechanical valve.
Project Conclusion
The project was successful in the fact that a
prototype was manufactured and tested. The
concept was proven to be a valid idea that
with further development could be used for
future applications within the aviation
industry.
Out of five tests, the system worked correctly four times, giving it an 80% success
rate. The test results were analysed against requirements so that the success of the
project could be determined.