We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

What Is a Flow Line?

Malcolm Tatum
Updated: May 17, 2024

Flow lines are pipe lines that are constructed to direct the flow of some type of liquid or gas from a source to either equipment used to process the substance or to some type of storage facility. It is not unusual for a flow line to be equipped with electronic monitoring devices and other features that make it possible to control the rate of that flow during the transfer. Depending on the exact function of the pipe flow line, various safety regulations may apply to the construction and ongoing operation of the system.

A common example of a flow line is used in the collection and processing of oil. While system designs for the line may vary somewhat, a basic line on a drilling rig will require the use of piping that has a larger diameter. At one end, the pipe is connected to what is known as a bell nipple just under the drill floor. It is at this point that the oil enters the pipeline. At the opposite end, the line is connected to what is known as a possum belly. The belly, which is simply a wider section that serves as a return line, then routes the product to tanks that filter impurities from the oil and store the collected product.

A similar process is used with a water flow line. Many municipal water systems utilize the line to route water that is extracted from sewage systems and route the contaminated water to purification facilities. Some systems utilize a series of filters that help to remove some of the larger contaminants for processing in a different area of the plant. The pipe flow line moves the water through the plant, where it emerges and can be returned to the municipal water system or allowed to flow into a body of water such as a stream, river, or lake. Since the water has been decontaminated, it poses no threat to any marine life in the body of water.

The construction of a flow line normally involves the need to comply with any governmental safety and structural regulations that are in force in the area where the line is located. Doing so helps to ensure that the potential for the system to fail and the opportunity for contamination or danger to lives and the surrounding environment is kept to a minimum. Periodic inspections of each section of the line help to make sure the system remains in compliance with those rules and regulations.

About Mechanics is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Malcolm Tatum
By Malcolm Tatum
Malcolm Tatum, a former teleconferencing industry professional, followed his passion for trivia, research, and writing to become a full-time freelance writer. He has contributed articles to a variety of print and online publications, including About Mechanics, and his work has also been featured in poetry collections, devotional anthologies, and newspapers. When not writing, Malcolm enjoys collecting vinyl records, following minor league baseball, and cycling.
Discussion Comments
By anon254317 — On Mar 12, 2012

How are flowlines stored in the supply base before the movement offshore?

By allenJo — On Mar 01, 2012

@Charred - A flow line in a drilling rig is a great tool, until it ruptures. Some of the worst oil rig disasters have had broken flow lines that have seeped millions of gallons of oil into the ocean, contaminating wildlife for miles on end.

I remember watching one such disaster a couple of years ago, and every day the news would come on telling you how much oil was leaking into the ocean.

Onscreen you would see the actual flow meter which measures how much and how rapidly oil was leaking. I’m all in favor of drilling for oil but there is no excuse for these kinds of disasters.

By Charred — On Feb 29, 2012

Isn’t it wonderful to realize that polluted water is directed from a sewer and into a lake after filtration? Actually the thought seems kind of grotesque when you think about it but it’s a testament to the effectiveness (I hope) of modern filtration systems that this process takes place.

I think we should be using flow lines to large basins to collect, purify and redirect rain water. Some people say that rain water is polluted and that you shouldn’t drink it, but it can be treated just like anything else I’m sure. Even the industrial pollutants can be removed in my opinion.

Malcolm Tatum
Malcolm Tatum
Malcolm Tatum, a former teleconferencing industry professional, followed his passion for trivia, research, and writing...
Learn more
About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.

About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.