JUST WHEN YOU HAD SEEN IT ALL: THE VALUE OF HIGH FREQUENCY PRESSURE DATA James Dunning, CEO james.dunning@syrinix.com tel: 415-992-8040
PEOPLE DON T UNDERSTAND THE PRESSURE ON ME
AGENDA Why worry about transients? The optimal measuring rate Strain Rate v Pressure Case studies
PRESSURE TRANSIENTS Sources Events Pain
WATER HAMMER OR TRANSIENTS The Proper opening and closing of valves is fundamental to safe pipeline operation An example: 800 ft. long pipeline, water flowing at 4 ft. per second The pressure in the line at the downstream valve is 60psi If the valve is closed over a 10 second period, the pressure increases to 82psi, i.e. water hammer increased pressure by 22 psi Pf = ((0.070VL)/t)+Pi Pf = Pressure resulting from transient (water hammer) V = Change of velocity of liquid L = upstream pipe length t = Valve closing time Pi = inlet pressure (before transient)
Change in Pressure (psi) AND AGAIN BUT FASTER 250 200 150 100 50 0 1 3 5 7 9 Valve Time to Close (seconds)
SOURCES OF TRANSIENTS Aggressive pump control Un-moderated commercial and industrial customers Configuration changes Hydrant flushing Pump failure PRV instability Pipeline burst Incorrect valve operations
Pressure (PSI Gauge) GAINING A CLEARER VIEW 400 LVVWD - transient at 16 samples/second 350 300 250 200 150 100 50 75 PSI 0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 Time (seconds)
Pressure (PSI Gauge) GAINING A CLEARER VIEW 400 LVVWD - same transient at 32 samples/second 350 300 250 200 206 PSI 150 100 50 0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 Time (seconds)
Pressure (PSI Gauge) GAINING A CLEARER VIEW 400 LVVWD same transient at 128 samples/second 350 300 323 PSI 250 200 150 100 50 0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 Time (seconds)
LAS VEGAS VALLEY WATER DISTRICT BEFORE Maximum pipeline rating 13 psi to 323 psi and immediately fell to -13 psi. This range was spanned in 0.047 seconds
LAS VEGAS VALLEY WATER DISTRICT BEFORE Maximum pipeline rating Repeated unexpected transients exceeding 300psi
LAS VEGAS VALLEY WATER DISTRICT AFTER Maximum pipeline rating Changes made to valve operations to calm the network, mitigate the risk of further breaks and prolong the life of the main.
ALIASING
128 s/s
IT IS NOT JUST ABOUT PRESSURE
FLAVOURS OF TRANSIENT THE TRADITIONAL User sets pressure threshold Pressure monitored at X samples per second continually if a transient detected If pressure exceeds threshold then alert triggered
WHEN TRADITIONAL IS NO LONGER ENOUGH Rapid pressure changes are overtly unacceptable when pressure rises to a high level The traditional measurement of pipeline maximum pressure ratings geared to that BUT
WHEN TRADITIONAL IS NO LONGER ENOUGH Rapid pressure changes are overtly unacceptable when pressure rises to a high level The traditional measurement of pipeline maximum pressure ratings geared to that BUT Rapid changes in pressure are similarly stressful to pipes even if the maximum pressure does not reach a designated pressure threshold each pressure change places a strain on the pipeline if that strain is applied/removed rapidly within a short period then it can be as damaging
FLAVOURS OF TRANSIENT THE TRADITIONAL Maximum pipeline rating Patented S3 approach Monitor at high speed continuously no sampling Focus not on pressure but on energy dissipation If the level of energy dissipated is sufficient, an alert is triggered Combine with precision time sync ing
NETWORK CALMING WORKS!
COBB COUNTY MARIETTA Background: Wholesale water provider to 12 customers/ municipalities 850,000 end users 150MGD 75 mile transmission main 36-54 line Combination of PCCP and DI 3 pump stations Pressure varies from 20 psi to 230psi Several of failures of 6 saddles in remote areas Large leakage undetected for several weeks
EXAMPLE OF HOW TRANSIENTS TRAVEL ROUND A SYSTEM This client has 75 miles of transmission main (PCCP and DI) 10 monitoring units deployed Transients can be tracked around the entire system Emergency Pump shut down
TAPPING SADDLE FAILURE ON 42 SECTION High sample data allows you to locate the event very accurately, by timestamping the transient wave at each monitoring location Pressure data SCADA showing flow data
TRANSIENT SIGNAL PICKED UP AND TIMESTAMPED AT TWO LOCATIONS
PATENTED TECHNOLOGY TRIANGULATES THE SOURCE OF THE TRANSIENT i.e. we locate the main break by monitoring pressure
WASTEWATER Standard PipeMinder-S uses hose to connect pipeline to pressure transducer in unit Significant risk of ragging and blockage of hose, with performance impact. PipeMinder-C is designed specifically for Force Main environments.
ACTUAL DATA FROM NA INSTALLATION Repeated pump starts and stops, every 20 mins Showing 15 minute average maximum and minimum pressures, but also high sample data
SUMMARY Monitor pressure on force mains Identify when the pump cycle is abnormal Early warning of an issue that is causing the pumps to work harder Back up Blockage Cavitation Pump failure Deviations from normal pumping head can indicate block main, clogged pump, burst or large leak. Drain down of main due to leaks or passing NRV Allows operators to take remedial action Identifies potentially damaging pressure surges, or repetitive pressure waves which may cause line failure due to repetitive stress More information on what s going on in your force main.
QUESTIONS? James Dunning Syrinix Inc james.dunning@syrinix.com Tel : 415-992-8040