Woodstock manual Flexible Duct, Plastic Duct, Operations, Model W1823 Mfg. Since 9/10

OPERATIONS

Model W1823 (Mfg. Since 9/10)

Flexible Duct

Flexible hose is generally used for short runs, small shops and at rigid duct-to-tool connections. There are many different types of flex hose on the market today. These are manufactured from materials such as polyethylene, PVC, cloth hose dipped in rubber and even metal, including steel and aluminum.

The superior choice here is metal flex hose that is designed to be flexible, yet be as smooth as possible to reduce static pressure loss.

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 Figure 27. Example of flexible metal duct. not quite have the flexibility 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 drainage-type vent hose in your 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. For example, polyethylene hose is well suited for the removal of particulate matter, especially sawdust, since it is durable and completely flexible. Also, it is very economical and available in a wide variety of diameters and lengths for most applications.

Plastic Duct

The popularity of plastic duct (Figure 28) 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 build- up.

Figure 28. Example of plastic duct and

components.

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