What is Air Lock?

A demonstration and brief explanation of air lock in fluid pipelines.

If you assume that gasses don’t get into pipes or that they can’t constrict the flow, you might design a pipeline that doesn’t work. Luckily for engineers, this is a well-known phenomenon in pipe systems. It’s just one of the complexities that come with the job and we’ve come up a with a lot of creative ways to overcome it.

Writing/Editing/Production: Grady Hillhouse
Director: Wesley Crump

Tonic and Energy by Elexive is licensed under a Creative Commons Attribution License

This video is sponsored by HelloFresh.

[SuomiFinlandPerkelee]

This may be the only YouTube channel that answers the question brought up in the video title during the first few lines. No clickbait nonsense, no long-dragging filler talk just to make the video longer. Just simple, straightforward and straight to the point explanations. Keep up the good work!

[gufu]

Grady: A civil engineer who frequently discusses the strengths and limits of materials within specific design parameters and expected uses.
Also Grady at 8:47: scrapes a metal spoon around the inside of a teflon-coated pot.

[juanyeap]

This channel inspired me to become a student of Civil Engineering, never thought I'd be interested in sewage and drainage and other public infrastructure. Thanks dude!

[woods-garage]

I have to say, I love how you deal with sponsors. I appreciate it so much that I often end up watching the full sponsor add at the end of the video. It is really irritating when you’re watching another channel, and mid sentence, a commercial interrupts what I was trying to learn about. In those cases, I completely ignore the commercial and focus on the timer counting down to when I can skip the commercial. Thanks again, and I love the content.

[fidjeenjanrjsnsfh]

Another form of air lock is very deadly.
An air emboli is when a bubble of air manage to enter your blood vessels and can block it leading to that organ not able to get blood and can prove fatal indeed.

[jamesnorris]

I was recently hired as a Process Operator for what will eventually be a Polypropylene plant. Having no experience in the industry previously, it amazed me to see the amount of trapped air that exist in our large 24" cooling water lines (when we filled them up we opened vents on top). Vapor lock in general has been a difficult concept for me, and your video was the first to answer and demonstrate it visually in a way that is easy to understand. Thanks a bunch!

[dylanhatch]

I’m graduating with a civil engineering degree in May! With an emphasis in water resource. I’m going to work at a firm that specializes in large scale irrigation systems, continuous acting air vents are a necessity in these large diameter pipelines! I love seeing the backyard experiments to better visualize what’s happening in the pipe. Love the videos thanks for all you do!!

[reid]

As a project manager for a mechanical contractor this concept is so important when flushing and filling any building’s piping system. Awesome video.

[jessephillips]

this was absolutely the most overlooked and frustrating yet easily avoidable problem that I dealt with when commissioning new wastewater facilities over the last decade. not only was this a problem in itself, but it effected system monitoring instruments and almost always set off alarms that indicated a different problem. I lost so many nights of sleep over "critical alarms" that amounted to "just air in the pipe"

[CarltonS]

This analysis is exactly right, but in my experience designing pipelines, it was not commonly understood by other engineers. I figured it out myself and used it in designing several pressure pipes (force mains) carrying sewage, and in many cases these had high points where gas from the sewage could accumulate. The problem there was that (1) a gas release valve at the high point could quickly become fouled with scum from the sewage, and (2) these high points were often in locations that were not practical to access for maintenance. So, I often designed the pumps to discharge against the added pressure created by air in descending legs of the pipe (referred to here as "waterfalls"). That required more electrical energy for pumping, but worked reliably with little maintenance, which is an example of trade-offs that are inherent in good engineering design.

[Coastfog]

You're one of the channels I'm most excited about when they release something new, maybe because you don't release new content that often. But boy do I know I'm in for a few minutes of some of the best content on YouTube...

[ProjectileGrommet]

God you are such a good writer. I’m a sophomore in biomedical engineering and your videos are such a fun buffer from my coursework to allow me to step back and appreciate the industry as a whole. I love your topics, but your scripts are just amazing. Keep it up!

[biggreenblob]

I work in wastewater treatment, and airlock is one of the more vexxing problems we have to deal with. It is unbelievablely frustrating to tear down and rebuild a large pump only to find that it still is not pumping enough, or not at all, then realize the air relief valve is simply plugged.

[Rottypops]

Practical Engineering : "Don't do it, don't do it..."
Brain : "Put googly eyes on it"

[dzim]

As someone who works as a engineer at an valve manufacturer who makes air valves, I really appreciate this video. I can now share this video to help explain to people why someone would even need something my company makes.

[ibrahimkhan]

Good video, learnt something new today: hydraulic grade line

@1:50 Besides increase in temp, agitation or chemical rxn, Pressure drop/ change in elevation also leads to the release of dissolved gases. One of the reasons why engineers must be careful where they place a pump during design is because pressure drops within a pump housing at certain elevations can lead to vapor locks.

Vapor locks are also not wanted in PFRs (plug flow reactors) because, as you said, dissolved air consume valuable space in a set pipe length where chemical rxn needs to reach an equilibrium within the given space-time.

[nloughner]

It's entertaining to me the differences and similarities in our industries. I do mechanical and plumbing design for buildings and we always go the way of sizing the pumps larger, even for some rather big runs of piping.

We do try and remove the air for open loop water systems but those are rather easily naturally vented. And the principles of flow with sir present are accounted for with drainage piping in building codes by having them oversized. I work with civil engineers and it seems somtimes we use different principles to handle the same problems before and after the pipes leave the building

[karrr]

The avergae view-time-to-length-of-video ratio on Practical Engineering must be through the roof. All videos are so concise and engaging.

[The.Talent]

Back when you first did the “what’s that infrastructure” series I sent you a photo of a 5 meter vertical pipe that comes directly out of the ground in my local park. Our suburb was once a swamp and I assumed that there was probably some gasses that somehow needed to vent from somewhere underground, but now I think I would probably guess it was one of these airlock valves. And I think I remember seeing sewage department signs near by to this pipe so I guess methane and other nasties could contribute to this airlock problem.
One weird thing though: why the height? The suburb was fairly flat and this was probably already at about the highest spot in the area, so maybe just to prevent tampering, or to allow nasty smells to dissipate before they fall to pedestrians nose height or something like that.

[davetourle]

Not only did I learn from this video, I also enjoyed the way it was explained and presented. Enjoyed it, thanks.