Tanks and Vessels Key Terms

Know tanks and vessels key terms to make the right choices for your business

By Denise Brown

If you need to store liquids on your property, you may need either tanks or vessels to do so. While tanks may or may not have pressure ratings, vessels do. Tanks and vessels also have a number of definitions associated with them; if you use tanks and vessels in any way, you should have a good understanding of tanks and vessels key terms. Read this guide to learn the basic terms you'll come across when shopping for the right product.

Tank

A tank is a storage unit that seldom has pressure applied to its contents. Tanks usually have thicker walls at their base to better support the contents.
Try: See the tanks at BHTank and read about welded tank construction.

Vessel

Vessels are containers that hold contents under pressure. The construction of a vessel must meet rigid specifications that put equal pressure on all parts of the vessel rather than on the base, as is the case with a tank.
Try: See the information about vessels at H2BestPractices. Shoemaker & Haaland make and install vessels for liquid processing facilities.

Head

The head is the top and bottom portion of a vessel. There are three basic forms of vessel heads: hemispherical, torispherical and elliptical. Hemispherical is one-half of a sphere. Torispherical vessels have a two-part head. The first part is the crown, and the knuckle connects the crown to the shell. Elliptical heads are oval shaped.
Try: Find examples of vessel heads at Technex.

Shell

The shell is the cylindrical part of a tank or vessel. Pressurized vessels have metal shells, while tank shells can be plastic, metal or concrete. Depending on the intended use of the shell, it may or may not have a lining.
Try: You can see a cylindrical shell at United Industries.

Buffer tank

A buffer tank serves as a pressure release source for a vessel. If necessary, overflow may run into a buffer tank. A buffer tank can also work efficiently to keep the contents of a vessel at a precise temperature.
Try: Heat-Flo Heating Products has an example of a buffer tank.

Couplings

Tank and vessel couplings connect storage containers with hoses or pipes so you can use the contents. Couplings extend from the head and are female-threaded connections.
Try: Find out more about couplings in the spec sheets at Central Fabricators.