What are typically referred to as large tanks with hemispherical heads?

The term "large tanks with hemispherical heads" most accurately describes cryogenic liquid tanks. These tanks are specifically designed to store gases or liquids that are at very low temperatures, such as liquid nitrogen, liquid oxygen, and other cryogenic materials. The hemispherical shape of the heads on these tanks helps to manage the stress caused by the internal pressure of the cryogenic liquids, ensuring structural integrity and safety.

The design is crucial for maintaining the low temperatures required to keep these substances in liquid form, as well as allowing for efficient loading and unloading of the liquids. Their construction often includes insulation to prevent heat transfer, which would cause the cryogenic liquids to boil off.

Other types of tanks like storage tanks, pressure vessels, and aqueous tanks differ in their purpose and design features. Storage tanks are generally used for a variety of liquids and do not necessarily have the specialized hemispherical design. Pressure vessels are designed to hold gases or liquids at a pressure substantially different from the ambient pressure, but they can take various shapes and do not specifically refer to those with hemispherical heads. Aqueous tanks typically hold water or water-based solutions and might not share the same structural design as cryogenic tanks.