1. GAS PURGE SYSTEMS ‘Manly Hydraulics Laboratory’ 28 th June 2011

2. HS23SL Bubble Unit Operating Principle Uses ‘dry nitrogen’ cylinder Transducer port Riverline port Purge valve Supply Metering valve Balance tube Flow tube Manifold Differential regulator Provides a constant ‘differential’ of 3-5 PSI (21-35 kPa) to maintain a ‘positive’ pressure at the orifice HS23 bubble rate ‘pre-set’ at factory Eliminates risk of silicon oil entering ‘riverline’ ‘Quick Connect’ fitting available for field check of bubble rate Available in ‘dual-line’ or ‘dual orifice’ versions

3. Bubble Unit Typical Installation

4. Air Compressors – General Alternative to gas cylinders (Safety Issues) Effective air drying system essential - moisture ingress - aquatic growth Some Limitations – ‘riverline’ length < 200 metres - maximum head of 30 metres Low powered types available (12V: 38aH with solar) Can be used with either standard orifice (BU07) or large volume type GCO1P

5. HS45 AND HS55 COMPRESSORS Bubbler type system Two stage air dryer 12V Compressor HS55 comes with HS23 bubbler Available in single or dual line versions

6. HS45 Compressor (No Bubble Unit) Air entry point 12V motor 2 stage air dryer 13L tank (obscured) Controller Pressure gauge Supply line valve 12V power leads

7. HS55 Compressor (With Bubble Unit) Air entry point 12V motor 2 stage air dryer 13L tank (obscured) Controller Pressure gauge Supply line valve 12V power leads HS23SL bubbler

8. HS40/3100 ‘Air Force’ Compressor Dual Air Dryer cartridges Riverline port Riverline valve Tank pressure gauge WL3100 P/T LED Status indicator 12V DC power lead Transducer isolation valve Test port

9. REMOTE MONITORING SYSTEMS Surface Water Level Monitoring HS40/WLS ‘Air Force’ Mk. II iCE³ modem (behind panel) 12V: 18ah battery iRIS150 data logger 20W solar panel (obscured)WL3100 transducer Bracket to suit 75mm NB pipe

10. Gas Purge (Open) System ‘Bubbler’ Single Orifice / Single Line

11. Gas Purge (Open) System ‘Bubbler’ Single Orifice / Dual Line

12. Gas Purge (Open) System ‘Bubbler’ Dual Orifice

13. Questions? Questions ?