Armstrong Pumps 572005-099 AX-40 Expansion Tank

Armstrong Expansion Tanks are designed to reduce tank sizes by up to 80% over standard designs. Expansion tanks use compressed air to maintain system pressures by accepting and expelling the changing volume of water as it heats and cools. Diaphragm or bladder tank designs isolate the expanded water from the pressure controlling air cushion – which is pre-charged at the factory and can be adjusted in the field to meet final system requirements

Manufactured in accordance with ASME Section VIII for unfired pressure vessels, the pre-charged diaphragm and bladder type tanks separate the air and water within the tank providing the following benefits.

• Tanks can be size up to 80% smaller than a conventional tank
• Improved system performance
• Reduced system corrosion
• Reduced requirement for chemical treatment
• Eliminates water-logged Expansion Tanks
• Stabilizes system pressure
• Dampens pressure transients (Water Hammer)
• Prevents Air Ingress

When a tank is pre-charged to the minimum system operating pressure (PMIN), it accepts only the expanded system water as the temperature increases. The highest temperature condition will have compressed the pre-charge to the maximum system operating pressure (PMAX). As the temperature decreases, the expanded water is pushed back into the system by the tank pressure. This design allows for a smaller tank, since space for charge water to compress air at atmospheric pressure to PMIN is no longer necessary, as it is when using a conventional expansion tank.

Applications
Pressure stabilization in water based mechanical systems such as booster installations, boiler systems, and chiller plants

Materials
Carbon steel (shell), heavy duty Butyl (diaphragm)

Performance range
AX diaphragm expansion tanks: 8 to 211 US gpm flow