Wolter · 4 series
Centrifugal fans
Wolter centrifugal fans serve where the ductwork creates high resistance: in air handling units, industrial systems, kitchen extract and aggressive media.
In a centrifugal fan the air enters along the impeller axis and leaves radially, and the scroll casing collects the flow and guides it to the outlet. This design develops higher pressure than an axial fan, which is why centrifugal fans are the main type for air handling units and long duct networks.
The Wolter range:
- ERS / DRS — direct drive from an external-rotor motor, single (ERS) or double (DRS) inlet, sizes 180–400;
- TN / HN — single inlet on an IEC flange or foot motor, forward-curved (TN) or backward-curved (HN) blades, 160–630;
- TRZ / HRZ and TRE / HRE — belt drive, up to 150,000 m³/h and 3,500 Pa, 160–1000;
- KAF / KAT — insulated kitchen extract boxes with the motor out of the airstream, air up to 120 °C;
- CHEM — chemical resistant plastic fans for aggressive media (described below).
Series
Wolter centrifugal fan series
ERS / DRS — direct-driven centrifugal fans
Scroll centrifugal fan with the impeller on an external-rotor motor: single (ERS) or double (DRS) inlet, sizes 180–400.
TN / HN — centrifugal fans on IEC motors
Single-inlet centrifugal fan on an IEC flange (F) or foot (Q) motor; forward-curved (TN) or backward-curved (HN) blades.
TRZ / HRZ — belt-driven centrifugal fans
Belt-driven scroll fans: single and double inlet, forward-curved, backward-curved or PP impellers; up to 150,000 m³/h and 3,500 Pa.
KAF / KAT — kitchen extract boxes
Insulated extract box with the motor out of the airstream on a swing-out door: kitchen extract and heavily contaminated air, −30…+120 °C.
Series comparison
Forward- or backward-curved
Forward-curved impellers are used in the TRZ, TRE, TN and KAT series, backward-curved ones in HRZ, HRE, HN and KAF. On the belt-driven fans Z stands for double inlet (TRZ, HRZ) and E for single inlet (TRE, HRE). The impeller type is chosen from the duty point, the permissible noise and the energy use.
CHEM chemical-resistant fans
For laboratories, electroplating and chemical plants, hospitals, food and electronics production and clean rooms, Wolter offers CHEM plastic centrifugal fans. Casings are polypropylene (PP), PVC, polyethylene (PE), PVDF or GRP; the backward-curved impeller is PP with a cast-in steel hub (PA, PC, PVC or PVDF on request). The permissible temperature depends on the material: PVC up to 60 °C, PP up to 80 °C, GRP up to 100 °C, PVDF up to 120 °C.
Sizes 75–400, direct or belt drive; the Chemco programme covers airflow up to 100,000 m³/h and static pressure up to 4,000 Pa. An anti-static casing material is available; the manufacturer does not state ATEX certification. CHEM fans are made under the Chemco name by Wolter’s joint venture in China (Dongguan Wolter Chemco Ventilation).
What we need for a selection
Airflow, total system pressure, composition and temperature of the medium, noise requirements and the installation location. From this we select the impeller type, drive, casing version and accessories and compare the options by energy use.
Applications
Where they are used
Malls, offices and hotels
Roof, centrifugal, duct and cabinet fans for retail, office and hotel buildings.
Learn moreIndustrial ventilation
Axial and centrifugal fans for workshops, chemical-resistant plastic fans, versions for hot air and explosive atmospheres.
Learn moreMarine and port ventilation
Marine versions of axial and centrifugal fans for ships, ports and shipyards on the Baltic, the Black Sea and the Caspian.
Learn moreFAQ
Frequently asked questions
Which centrifugal fan suits an air handling unit?
What are KAF/KAT boxes for?
They are insulated extract boxes with the motor out of the airstream, for kitchen extract and heavily contaminated air from −30 to +120 °C. The motor is mounted on a swing-out door.
Are there fans for aggressive media?
Yes, CHEM plastic fans with casings in PP, PVC, PE, PVDF or GRP, for temperatures of 60–120 °C depending on the material.
Are there centrifugal smoke extract fans?
Need equipment selection or a system design?
Send us the layouts or the brief — we will prepare a selection, a calculation and a quotation.