Which equipment is known for controlling pressure in a system?

The pressure vacuum breaker is specifically designed to control pressure within a liquid system by preventing back siphonage and maintaining pressure balance. It functions by allowing air into the system when a negative pressure condition occurs, which helps to prevent any potential collapse of the system due to pressure differences. This mechanism ensures that the system operates efficiently and safely under varying pressures.

In contrast, a vacuum seal is primarily used for creating airtight seals, which is not directly related to pressure control. A ballast pump is a component used to manage the ballast water on ships, which involves filling and emptying tanks to maintain stability and buoyancy, but it does not primarily focus on pressure management. An oil separator is designed to remove oil from water, usually in waste management applications, and while it may deal with pressure in its operation, it is not fundamentally a piece of equipment used for pressure control.