Wessels Bladder & Diaphragm Expansion Tanks

February 9, 2010  |   Posted in Auxiliary Equipment, Expansion Tanks, Products, Wessels    

Thermal expansion tanks are designed for pressure control in a hot water system. The building’s water heater or water heating system typically creates the thermally expanded water. A properly sized thermal expansion tank will accommodate this additional volume of water created through expansion during the heating cycle, and control the system pressure increases, keeping pressures from reaching critical limits.  Wessels’ thermal expansion tanks are offered in industry’s broadest range from 2 to 4,000 gallons and up to 250 psi.

Pressurized thermal expansion tanks differ from plain steel expansion tanks in that a flexible bladder or diaphragm separates the air cushion from the system fluid. The air side pre-charge of the tank must be field adjusted to equal the system supply pressure. As the system water expands, the bladder expands open, pushing against the air cushion to accept the expanded water.

Bladder Tanks

TXA Series (ASME)

The TXA Series bladder style tanks boast many advantages over other styles of thermal expansion tanks. The bladder can be easily replaced in the field. The free standing models have a system connection at the bottom of the tank.  The TXA tank is designed to prevent any harmful build-up of dirt, grit or system contaminants in addition to providing for easy draining to assist in establishing proper air charge.

Diaphragm Tanks

TTA Series (ASME)

TTA Series tanks are actually a tank within a tank. A non-ASME bladder tank is placed in an ASME tank. The bladder cannot expand any larger than the inner tank that contains it so the acceptance volume of the TTA tanks is less than the total tank volume. The bladder is fixed and cannot be replaced. TTA tanks are generally less costly than the comparable TXA tank.