How Does a Hydropneumatic Water Tank Work?

Written By
Alex Burke
Alex Burke
Published: May 22, 2009
Updated: Nov 20, 2021
2 minute read

Functions Of Hydropneumatic Tanks

Components Of Hydropneumatic Tanks

Tanks vary in size and get very large. They're usually horizontal in design, with a capacity from about 2,000 gallons to 30,000 gallons or more. The system's needs determine the size of the tank. Sensors monitor the level of the water and pressure in the tank. These sensors are the automatic controls that operate the compressor. There are openings at either end of the tank; one is a tank access opening (where the water enters the tank), and at the other end is the pressure gauge and pressure switch (which controls the well pump). At the bottom of the tank is a drain opening and valves that are opened and closed to allow the regulated release of the water into the system. At the top is the air compressor and water level sensors, along with a pressure relief valve.

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Adding More Air

There are two ways air can be added to a pressure tank: air volume control systems or air charging systems. Air is added when the water pump cycles. More modern pumps use the air volume control system, which contains an air compressor, pressure switch and a liquid level switch. A sensor connected to the liquid level switch drops down into the tank and monitors the water level. The pressure switch monitors the air pressure via a sensor. When air dissolves into the water, it causes the water level to rise and the air pressure to fall. The compressor triggers and pumps air into the tank when the water falls below the water level sensor and the air pressure falls below the setting on the pressure switch. A time delay prevents rapid cycling of the compressor.

Hydropneumatic Water Tanks

Common uses for hydropneumatic tanks are in well water processes. They can also be found in irrigation pumps and sprinkler pumps. Drawdown is the term used to describe the amount of water a particular system uses during a water cycle. This amount of water or drawdown must be known before a hydropneumatic water tank size can be chosen. Tanks can also have linings or bladders that separate the water from the inside of the metal tank.

Alex Burke

Alex Burke holds a degree in environmental design and a Master of Arts in information management. She's worked as a licensed interior designer, artist, database administrator and nightclub manager. A perpetual student, Burke writes Web…

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