Frequently Asked Questions (FAQs)
1. What kind of duct for dust collection?
There are two main types of ducts for dust collection: flexible hose duct and hard, fixed duct. Flexible hose duct is made of rubber or plastic with a metal grounding helix to prevent static electricity buildup. It is important to ground the hose at each end to avoid sparks.
Using a regular vacuum cleaner may not be sufficient for dust extraction. The HSE regulations state that a vacuum cleaner must extract at least 99.9% of dust, while a normal vacuum only extracts around 80%. A proper dust extractor ensures that even the smallest particles are effectively removed.
3. How do you size ductwork for a dust collection system?
The sizing of ductwork for a dust collection system depends on the type of dust. For metalworking dust, the recommended velocity is 5000 FPM in branches and 4500 FPM in the main trunk line. For woodworking dust, the velocity should be 4500 FPM in branches and 4000 FPM in the main trunk line. For plastic or other light dust, the velocity should be 4500 FPM in branches and 4000 FPM in the main trunk line.
4. What is the minimum duct velocity for dust collection?
Dust collectors are designed to move a high volume of air at low static pressure levels. The minimum air velocity required for effective waste capture at the tool is typically 3500 - 4500 FPM (feet-per-minute). This ensures efficient removal of dust and debris.
Yes, round, galvanized steel ducting is suitable for conveying airborne dust and debris. It is designed to withstand the high air pressures created by dust collection systems. The components are specifically designed to minimize air resistance, featuring gradual splits and large radius turns.
6. Can I use dryer duct for dust collection?
While some people have used dryer duct for dust collection, it is not recommended as it may not be designed to handle the requirements of a dust collection system. It is best to use ducting specifically designed for dust collection to ensure optimal performance and safety.
7. Can I use a vacuum instead of compressed air?
Using a vacuum cleaner instead of compressed air is not recommended for cleaning computer components. A vacuum can create static electricity that can damage the components, and the suction can be strong enough to damage fans. It is best to use canned air or other appropriate cleaning methods.
8. How many CFM can a 4 inch duct handle?
A 4-inch pipe can handle approximately 395 CFM (cubic feet per minute) at a velocity of 4500 FPM. This means that if a machine requires around 400 CFM for waste removal, a 4-inch pipe would be suitable for that purpose.
9. What size pipe to use for dust collection?
For dust collection, it is recommended to use PVC sewer and drain pipe instead of the heavier and more expensive schedule 40 PVC. Joints should be fastened with screws instead of glue for easier access in case of jams. In terms of diameter, a 5-6 inch line is typically run to the heaviest chip-producers, such as planers and jointers.
10. What is the minimum CFM for shop dust collection?
The CFM (cubic feet per minute) required for shop dust collection varies depending on the size and number of woodworking tools being used simultaneously. Most woodworking equipment requires approximately 250-1000 CFM. For example, an average size table saw, planer, or jointer with 2-5 inch diameter ports would need around 300-600 CFM for effective cleaning.
11. Can duct velocity be too low?
If the velocity in ductwork is too low, it can lead to dust settling in the ducts. However, if the velocity is too high, it can cause premature wearing of the ductwork, especially when dealing with abrasive dust. Additionally, high velocity can result in increased static pressure within the system. It is important to find the right balance to ensure optimal dust collection performance.
