ВМ, ВМ-Дл, ВМ-I and ВВСМ types mill FD fans of single-side suction are designed for pulverized coal pneumatic transportation in pulverized-coal systems of the solid fuel fired boilers. Being of quite low capacity FD fans of this type generate high pressure. Besides they are subject to intensive abrasion effect of pulverized coal.
To protect ВМ-Дл type FD fans from wearing, additional wear-preventive blades are installed. Impeller blades of ВМ-I type FD fans are protected with surfacing of wear-resistant alloy. Along with surfacing, design of ВВСМ type FD fans provides a possibility of worn-out blades replacement. Inner surface of ВМ-I type FD fan scroll case shell ring is covered with detachable low-carbon steel armor plates aimed at protecting from abrasive wear. For the same purpose armor plates made of chilled cast iron are harnessed in ВВСМ type FD fans.