New induced draft fans
GERMANY – Efficient induced draft fan designed by ebm-papst.
ebm-papst has expanded its existing range of EC induced draft fans specifically adapted for the large heating outputs required for use in biomass heaters. Their size 250 blower completes and extends the range of single-side intake centrifugal fans for wood pellet, wood chip or firewood heating systems. Sizes 140 to 210, principally used in ovens in residential buildings, were until now the only blowers available.
The size 250 blowers ensure and enable the extraction of hot combustion gases in applications such as wood chip heating systems of up to 250 kW. In this process, the blower delivers an air performance up to 1,000 m³/h. These systems are necessary for heating and hot water in public and commercial buildings.
In conjunction with the fan, the GreenTech EC external rotor motor forms a compact, space-saving unit which is also robust and durable. Other features of the EC motor are a 0-10V control input and an additional MODBUS-RTU interface. This interface renders the task of monitoring the motor (e.g. temperature or speed monitoring) a simple one.
The EC motor has been further modified so that the commutation electronics are located as far away as possible from the hot combustion chamber. As a result, the electronic components are better protected against the very high temperatures which are inevitably generated. An optional special shaft seal prevents any flue gas from leaking through the shaft gap. This is particularly important in a balanced flue operation, as the air quality of the room would otherwise suffer. The hood of the induced draft fan is made from hot-dip galvanised sheet steel, thus ensuring a robust construction. The cooling vents also help to ensure optimum heat dissipation for the motor. The fans conform to protection class IP54 requirements and also feature maintenance-free ball bearings.
Users of the new induced draft fan can now choose between AC and EC motors. However, induced draft fans combine considerably more efficiently with GreenTech EC motors. At full load, the EC blowers consume up to 30 percent less energy, and even less in the partial load range, reducing the cost to both operators and the environment. The new size 250 blowers will be available for purchase from mid 2015.