Circulating Pumps

Circulating pumps are centrifugal pumps built to move liquid around a closed loop. They keep the flow rate, pressure and temperature steady. Their job is to push water, coolant or heat transfer fluid through pipes that form a closed circuit. They do not lift liquid to a higher place - they only offset the friction that the liquid meets as it moves through the loop. Installers use those pumps in house plus building HVAC systems, hydronic heaters, solar thermal arrays and industrial coolants or lubrication lines. In heating the pump sends hot water from the boiler to radiators or underfloor tubing and brings it back again - every room stays at the set point. In cooling the pump moves chilled water to air handlers or process exchangers but also returns it to the chiller. The pump contains an electric motor and a spinning impeller inside a casing. The blades hurl the liquid outward raising its speed - the casing turns that speed into pressure. Because the loop is sealed, the same liquid repeats the trip indefinitely. To save power as well as run quietly, the motor turns only as fast as needed. Makers select metals, seals and coatings that tolerate the expected temperatures and resist corrosion - the unit lasts for years in houses, offices and plants. Circulating pumps keep the liquid moving or the temperature uniform in closed loop systems.