laajenemissäiliöön

A laajenemissäiliö, often translated as an expansion tank or expansion vessel, is a crucial component in many closed-loop hydronic systems, particularly those involving heating and cooling. Its primary function is to accommodate the natural expansion and contraction of the fluid within the system as it heats up and cools down. Water, like most substances, increases in volume when heated and decreases when cooled. Without a mechanism to manage this volume change, significant pressure fluctuations would occur within the system.

In a typical heating system, as the water heats, it expands, and this excess volume needs a place to go. The expansion tank provides this space. It usually contains a diaphragm or bladder that separates the system water from an air or gas cushion. As the system water expands, it pushes against the diaphragm, compressing the air cushion. This compression absorbs the increased volume, preventing excessive pressure buildup. Conversely, when the system cools and the water contracts, the compressed air cushion expands, pushing fluid back into the system and maintaining adequate pressure.

Expansion tanks are vital for protecting system components like pipes, radiators, boilers, and pumps from damage caused by overpressure or underpressure. They help ensure consistent system performance and longevity by maintaining a stable operating pressure range. The size and type of expansion tank are determined by factors such as the total volume of water in the system, the expected temperature range, and the desired operating pressure.