What is a K-Bottle?

There is a lot of jargon when it comes to pressure vessels, and k-bottles are a good example. You might have seen k-bottles annotated in a schematic or diagram, or listed in an email from a colleague, but do you know what they’re referring to? K-bottles are used to store pressurized gases, but they’re also referring to a specific type of gas storage container, which this article will explain below.

How are compressed gases stored?

When storing and transporting gases, many manufacturers and users will compress the gas so they can fit more of it in the same amount of space. This is because gases are made up of energetic molecules that are much more widely spaced than those in a liquid or solid, so it’s possible to compress them.

The energy in gas molecules resists compression. They want to be able to move around, and the closer together the molecules are, the less they can move. To keep them compressed requires specialized equipment and storage capabilities. This is where pressure vessels come in.

Pressure vessels are designed to withstand pressures greater than atmospheric pressure, so they can hold compressed gases that are denser than they would be under standard conditions. Different types of pressure vessels are used for different gases, sizes, and other requirements, and they have a lot of different names.

What is a k-bottle?

A k-bottle is a type of pressure vessel used for a variety of common compressed gases that holds a specific volume of gas. The “k” part of the name refers to the size of the bottle, and “bottle” is sometimes used in industry to refer to small cylindrical pressure vessels. K bottles meet the following specifications:

• Diameter: 9.25 inches
• Height: 60 inches
• Weight: 135 lbs
• Internal volume: 50 liters

You might also see k-bottles referred to as bottles or cylinders meeting the U.S. Department of Transportation standard 3AA2400.

Learn more

Have questions about k-bottles or other pressure vessel sizes? Rexarc is an expert manufacturer of standard and custom pressure vessels in carbon and stainless steel. We’d be happy to answer your questions and direct you to resources to learn more about pressure vessels – reach out to us today!