Pressure tanks and vessels come in various shapes and sizes and are designed to hold gases, vapors, and liquids at high pressures, usually above 15 PSIG. Storage tanks hold various liquids. Each type of tank has a unique set of properties and applications, but all play an important role in the safe and efficient operation of various businesses.

What’s the Difference Between Pressure Tanks & Storage Vessels?

Pressure tanks and storage vessels are pressurized containers that store gases and liquids. The main difference between these two types of tanks is the pressure at which they contain their media.

Pressure vessels store gases or liquids at a pressure above atmospheric pressure. Their Maximum Allowable Operating Pressure (MAOP) starts at 15 PSI but can reach up to 150,000 PSI. On the other hand, storage tanks have an MAOP of 15 PSI and only hold gases or liquids at atmospheric pressure. Also, pressure vessels are typically made from stronger materials such as steel or fiberglass, as they need to withstand higher pressures.

Different Types of Tanks & Vessels


There are three main types of pressure tanks:

  • Bladder: Bladder tanks have a rubber or synthetic rubber bladder that stores water. The principle behind a bladder tank is that as fluid fills the bladder it compresses the air in the tank. This air then puts pressure on the water in the tank, keeping the pressure constant.
  • Diaphragm: Diaphragm tanks work similarly, but instead of a bladder, they have a flexible diaphragm that divides the steel tank into two chambers. One chamber holds water, and the other chamber holds air. As water fills one chamber, the air applies force against the water chamber, maintaining constant pressure.
  • Air-over-water: Air-over-water tanks are traditional versions of pressure tanks with air filling the top part of the tank and fluid filling the bottom. The air puts pressure on the water, keeping the pressure constant until water is drawn out of the tank, decreasing the pressure. Air-over-water tanks are also commonly referred to as galvanized or stainless steel tanks.


Pressure vessels are designed to contain fluids or gases at high pressures and are used in various industries, from food and beverage processing to manufacturing.

  • Heat exchangers: Heat exchangers transfer heat between two liquids or between a liquid and a gas while preventing the two types of media from coming into direct contact with one another.
  • Process vessels: Process tanks carry out reactions or other production processes, such as distillation or filtration.
  • Storage vessels: Storage vessels store liquids or gases at high pressure, often for long periods.

How does a Pressure Vessel or Pressure Tank Fail?

There are several ways pressure vessel tanks can fail. The most common type of failure is material degradation, which happens when the material used to construct the vessel is not strong enough to withstand the pressure to which it is subjected. This can be due to an improper selection of material, incorrect design, or poor fabrication.

Another type of failure is structural discontinuity, which happens when there is a break or crack in the vessel’s structure. This can be caused by improper maintenance or a sudden increase in pressure. Finally, a reduction in the load-bearing capacity can also lead to failure. This happens when the vessel is not properly supported and begins to sag or collapse under its weight.

The safe operation of pressure vessels is essential for the welfare of workers and the general public. Unfortunately, pressure vessels can sometimes fail, leading to serious consequences. The most common types of failures are:

  • Brittle fracture
  • Stress rupture
  • Elastic deformation
  • Corrosion fatigue

Uses and Applications of Stainless Steel Tanks & Vessels

Highland Equipment Inc. specializes in designing and manufacturing high-quality stainless steel tanks and vessels for various industries. Below is an overview of the applications and uses of our sanitary tanks and vessels:

  • Pharmaceutical tanks store and transport sensitive materials for the pharmaceutical industry.
  • Food and beverage manufacturers use our tanks to store everything from wine and beer to milk and olive oil.
  • Dairy farms utilize our dairy tanks for the pasteurization of milk.
  • Breweries rely on our tanks for the fermentation and aging of beer.
  • We also create custom tanks and vessels for the cosmetics industry.

No matter the industry, Highland Equipment Inc. can provide the perfect solution for your storage needs.

Rely on Highland Equipment For High-Quality Pressure Tanks & Vessels

Tanks and vessels are an important part of many industries. Our process systems are vital to industrial food & beverage processing, pharmaceutical drug synthesis, dairy processing, alcohol production, cannabis extraction, and cosmetics processing.

If you need tanks or vessels for your company, request a quote from us. We can provide you with the best products for your needs, ensuring you get the most value for your money.