Bag tyre and inverted cone type whirlwind dust collectors can be used hand-in-hand to from twice dust removing system. When the ventilation capacitilies are consistent. Doing this can both extend the endurance of cloth bag, and enlarge the disposal capacity for dust. Our company can design and manufacture conduits and supply ventilation machines inaccordence with the custem's requirements and the real positions of the customer's dustcollectors.