Better filtration for single-stage collectors
by Dave Munkittrick
The cartridge filter is the first significant improvement in single-stage dust collection in more than 30 years.
Cartridge filters offer better filtration, better airflow and easier cleaning than bag filters (Photo 1). They are available on new dust collectors or as a replacement for the old filter bag on your existing single-stage machine. The upgrade doesn’t come cheap (approx $200 for the 20-in. cartridge). What’s really amazing about these filters, however, is they pack five to six times the filter area into a cartridge that’s smaller than the bag it replaces!
The filter material in cartridge filters is made of spun-bond polyester, capable of filtering dust particles down to 2 microns. Compare that to a typical woven fabric bag filter that struggles to capture dust at 30 microns.
A disposable plastic collection bag replaces the lower bag, because the lower bag no longer needs to do double duty as a collection sack and a filter.
A single-cartridge filter offers much more filter area than a single-bag filter (Photo 2). That’s because the filter material is folded or pleated like an accordion (Photo 1). The pleated filter design fits a ton of filter material into a small package. The increased filter area makes it easier for air to flow through the filter. We did some testing on the 1-1/2-hp single-stage collector in our shop and found that switching to a cartridge filter resulted in a 20-percent bump in cfm performance.
Dust-Free Filter Cleaning
Cleaning a bag filter often means transferring fine dust from the bag to your clothes, shop and lungs. Cartridge filters put an end to that nonsense. There’s no need to remove a cartridge filter from your collector to clean it. Jet and Penn State cartridge filters feature a set of offset paddles built into the filter (Photo 1) that allow you to knock the dust cake off the pleats with a few turns of a crank (Photo 3). All that nasty wood dust drops harmlessly into the plastic collection bag for easy disposal. This system keeps you, your shop and lungs cleaner.
Easy Installation and Bag Changes
The cartridge filters we tried were easy to install on older model single-stage collectors. Just drop them onto the bag flange where your upper filter bag normally goes. The foam gasket on the cartridge filter makes an airtight seal on the rim (Photo 1).
Better Than Aftermarket Bags
High-performance aftermarket bags cost less than a cartridge, and some claim to filter to 1 micron. The trouble is these bags are undersized and that means reduced cfm performance for your collector. Also, because the bags are too small for the amount of air being forced through them, a lot of dust gets pushed right through the bag and back into your shop.
You can get custom bags made to the correct size that cost about $120. That’s almost the cost of a cartridge filter and you’d still be faced with the cleaning hassles inherent in any bag system.
There are some brand-new cartridge filter systems in the pipeline for the coming year:
– Delta is developing a new filtration system to replace their bags. Still in the research phase, this system may be completely different than the cartridge filters featured in this article.
– Laguna is completely redesigning their line of cartridge-based dust collectors. Expect their release sometime soon.
– SECO offers a complete line of dust collectors with cartridge filters. Plus, they have a new line of self-contained hybrid dust collectors that use cartridge filters and offer some of the benefits of a cyclone system without the space requirements.
Photo 1: Pleated filter material offers increased airflow and better filtration than typical bag filters. A foam gasket creates an airtight seal on the collector-bag flange. No more hassles with leaky band-clamp seals. Flappers allow you to clean the pleats of dust build up without having to remove the cartridge.
Photo 2: Cartridge filters contain 5 to 6 times the filter area of a standard bag filter but they take up less space. The large filter area allows more air to pass through, which in turn increases the air-moving performance of your dust collector by about 20 percent.
Photo 3: Cartridge filters are easy to clean. There’s no need to remove the cartridge. Just turn the handle and a pair of flappers (Photo 1) inside the cartridge knock the dust cake from the pleats. The fine dust from the filter drops harmlessly into the disposable collection bag below.
This story originally appeared in American Woodworker November 2003, issue #104.
amazon.com, www.amazon.com Jet DC-1100CK, 1-1/2 hp, #708626CK; $450 Jet DC-1200CK 2 hp, #708634CK; $500 Jet DC-1900CK 3 hp, #708637CK; $870 Retrofit canister and filter for 20″ collectors, #708739K; $190 Replacement plastic collection bags, #709563; $14 for a pack of 5. Kufo Industries Corp. (888) 558-4628, www.kufogroup.com DC102 2 hp; $899 DC103 3 hp; $1,095 DC105 5 hp; $1,795. Laguna Tools (800) 234-1976, www.lagunatools.com Laguna Filter 25; $895 Laguna Filter 50; $1,500. Penn State Industries (800) 377-7297 www.pennstateind.com DC2-CF 1 1/2 hp; $450 DC250-CF 2 hp; $470 Retrofit canister for 20″ collectors, #DCANISTER; $20 Replacement plastic collection bags, #DCPB7; $16 for a pack of 10.