Flexible Duct
Flexible hose is generally used for short runs, small shops and at rigid
The superior choice here is metal flex hose (see Figure 42) that is designed to be flexible, yet be as smooth as possible to reduce static pressure loss.
Figure 42. Example of flexible metal duct.
There are also many kinds of pure plastic flexible hose, such as non-perforated drainage type hose and dryer vent hose. Drainage type hose, while being economical, does not quite have the flex- ibility required for dust collection. The inside of the duct is also deeply corrugated and can increase the static pressure loss by as much as 50% over smooth wall duct. Dryer vent hose, while being completely flexible, is non-resistant to abrasion and has a tendency to collapse in a negative pressure system. We DO NOT recommend using dryer vent hose in the dust collection system.
If using flex-hose, you should choose one of the many types that are designed specifically for the movement of solid particles, i.e. dust, grains and plastics. However, the cost of specifically designed flexible duct can vary greatly. Grizzly offers polyethylene hose, which is well suited for the removal of particulate matter, especially saw- dust, since it is durable and completely flexible. Polyethylene is also very economical and avail- able in a wide variety of diameters and lengths for most applications.
Plastic Duct
The popularity of plastic duct (see Figure 43) is due to the fact that it is an economical and readily available product. It is also simple to assemble and easily sealed against air loss. The primary disadvantage of plastic duct for dust collection is the inherent danger of static electrical
