Designing the System, General, Material Selection

SECTION 5: DESIGNING THE SYSTEM

General

The Model G9958 can be operated as either a stationary or a mobile unit. There are advantages and disadvantages to both set-ups. The advan- tage of the mobile system is eliminating the cost of many ducts and fittings. On the other hand, the stationary system is more versatile and conve- nient.

The Model G9958 is designed to be a central dust collector system. Locate the dust collector in an out of the way location such as a corner or sepa- rate room. The dust collector is capable of col- lecting dust from up to four machines running simultaneously. Because of the large suction capacity of the Model G9958, great flexibility is possible in the planning and designing of your dust collection duct layout. Grizzly offers a com- plete line of dust collection accessories for setting up a stationary system. Additionally, Grizzly offers a complete guide book entitled Dust Collection Basics.

Whatever system you choose, always make sure there are no open flames or pilot lights in the same room as the dust collector. There is a risk of explosion if dust is dispursed into the air.

Material Selection

You have many choices regarding main line and branch line duct material. In most commercial workshops, the main line and branch lines are usually metal duct. Flexible hose is then used to connect each machine to the branch lines. In the case of small home shops, flexible hose may be used for both main line and branch line ducts. Plastic duct is also a popular material for home shops. Please be aware that there is a fire or explosion hazard if plastic duct material is used for dust collection without being grounded against static electrical charge build-up. This topic will be discussed later in the manual.

G9958 4 H.P. Dust Collector

METAL DUCT

Metal duct comes in many varieties. Stove pipe, heating/ventilation duct and duct made especially for dust collection are all options. Advantages of metal duct is its conductivity and that it does not contribute to static electrical charge build-up. However, static charges are still produced when dust particles strike other dust particles as they move through the duct. Since metal duct is a con- ductor, it can be grounded quite easily to dissipate any static electrical charges. However, metal duct is generally more expensive than plastic duct and it is not usually airtight unless specifically manu- factured for dust collection. Specially manufac- tured metal duct, on the other hand, is quite expensive. Metal duct is also generally more diffi- cult to cut and assemble.

FLEXIBLE HOSE

Flexible rubber hose, polyethylene, plastic flex- hose and other flexible ribbed 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 polyethyl- ene, PVC, cloth hose dipped in rubber and even metal, including steel and aluminum.

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 flexi- bility 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.

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

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