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BURP PROUDLY:The Importance of Air Valves
Brian GongolDJ Gongol & Associates, Inc.
March 30, 2016
Iowa WEA Region 5 ConferenceHuxley, Iowa
Let's start with a beer keg
If you pump a few times, you add pressure
Pumping too much creates foamy beer
Beer is relatively incompressible
Releasing a little volume eases lots of pressure
Water in a pressurized system: Same behavior
Not zero like a solid (steel or concrete)
But close
Squirt guns and belly flops prove it
Everyone knows two ways you can get gas
1. Swallowing too much air
2. Eating something that generates gas
There are two ways to get rid of it
Having gas in your system is unpleasant
Gas stretches your elastic innards
Wastewater systems do not have the same elasticity
When gas collects, it doesn't have anywhere to go
But gas inside a force main is just as realas the gas you get from eating a burrito
Force mains are not elastic
Pressure inside does two things
1. Displaces water that should be flowing through
2. Places pressure on pipes that can cause damage
This is why we use air-release valves
[ ENTER: THE WIRE HANGER ]
But unlike your digestive tract, hard pipes have to stay full of something at all times
In addition to releasing air, we have to break vacuums as well
Four different types of valves need to be considered
1. Air-release
[ AIR-RELEASE VIDEO ]
2. Vacuum-breaker
[ VACUUM-BREAKER VIDEO ]
3. Air-vac
4. Combination air valves
[ COMBINATION AIR VALVE VIDEO ]
Where these are located
Typically some kind of air release at the pump site
Needed for priming
Frequently a site of air capture
Air-release at the highest point is not enough
Air release is needed at all local high points
Also recommended on long stretches of pipe rise
Vacuum-breakers typically needed at the same points
Weight of a column of water
4" diameter, 500' long 43.55 cubic feet 325.75 gallons
At 8.3 lbs per gallon: 2700 lbs. (a Honda Civic)
For big exhaust, air-vac valves may be enough
But if mains needs to "burp", get combination valves
Sizing is a little bit of black magic, but not too much
When in doubt, go big
Filling a pipeline/force main
Filling a pipeline/force main
Filling a pipeline/force main
Filling a pipeline/force main
Filling a pipeline/force main
Filling a pipeline/force main
Filling a pipeline/force main
Filling a pipeline/force main
Filling a pipeline/force main
Filling a pipeline/force main
Filling a pipeline/force main
Filling a pipeline/force main
Filling a pipeline/force main
Breaking a vacuum
Breaking a vacuum
Breaking a vacuum
Breaking a vacuum - refilling
Air valves are not shock absorbers, too
Water is not like air in a storm door cushion
But also unlike pushing on a pool cue
Energy is transmitted quickly but not instantly
Energy is conducted as a wave
Air valves and surge valves are complementary
Air is vastly more compressible than water
Water needs surge control to protect pipes
Surge is like a train starting or stopping
Energy transmits through couplers
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Surge in a filled force main
Don't make a bad situation worse
Low point main break - with vac breakers
Low point main break - with vac breakers
Low point main break - with vac breakers
Low point main break - with vac breakers
Low point main break - with vac breakers
Low point main break - with vac breakers
Low point main break without vac breakers
Low point main break without vac breakers
Low point main break without vac breakers
Low point main break without vac breakers
Low point main break without vac breakers
Low point main break without vac breakers
Low point main break without vac breakers
Low point main break without vac breakers
Low point main break without vac breakers
All the sizing in the world is useless if you don't maintain
Backflushing
[ BACKFLUSHING VIDEO ]
Risks damaging parts
May not remove buildup
Could just temporarily move the clog
Alternative: Wiping and scrubbing
[ CLEANING VIDEO ]
Isolation is important
Knife gate valves for isolation
Plug valves for isolation
Valves aren't just an accessory or a "want"
Proper valving is essential to the proper operation of a force main
Slam is the train sliding back downhill
Vacuum-breaking upon pressure drop
Air in solution in water: About 2%
Air restricts pipe diameter
Can be significant
Air pockets will build
Imagine trapping a tough balloon in the pipe
Lots of compression possible...
...but dangerous high pressure results
Upsurge and downsurge are hydraulic
Slam is mechanical
Slam comes from column reversal
Slam and surge are independent
Check valves are used for protection
Prevent simple column reversal
Ball check valves
Weighted-flapper check valves
Cushioned check valves
Non-slam check valves
Close fast enough to prevent slam
Example: Sudden power loss
Example: Sudden power loss
Example: Sudden power loss
Example: Sudden power loss
Don't close too fast for pumps and systems
Quick self-closure isn't actual slam
Slam is involuntary seating of the valve
Some valves can control both surge and slam
Checktronic Overcoming high head after bringing pump up to speed
Surge control valve
Water air-release valve
Sewage air-release valve
Wide-body air-release valve
To recap
Force mains need to burp Force mains need to pass gas Force mains need to swallow air Air absorbs some wave energy, but not all Air pressure, vacuums, and surge waves can damage pipes Well-maintained automatic valves are an important feature
You don't have to figure it out alone
Free surge analysis available Air-release analysis also available Call: 515-223-4144 Email: [email protected]
Questions?
Thank you for coming!
Thank you for your attention!
Contact us anytime with questions
Brian Gongol DJ Gongol & Associates 515-223-4144 [email protected]
References
Catalog photos of valves are courtesy GA Industries All other photos are original work by Brian Gongol. All rights
reserved.