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Technical Section Phone: 516-328-3970 www.technocnc.com  21 The Dust Collection System An  important  addition  to  workshops and machines is a dust collection system. Dust  collection  systems  make  shops cleaner,  safer,  and  extend  the  life  of  a machine. A   clean   shop   is   a   safe   shop. Uncontrolled dust can cause potentially serious health risks, contribute to messy work  environment  that  can  cause personal injury, and be the cause of premature machine failures.   Sawdust,   wood chips, and any other particles generated  by  cutting  the wood, particle board, plywood,   etc.,   become hazardous if they are inhaled. These products are created with   the   use   of   resins, alkaloids, silica, tannins, toxic organic    and    inorganic elements. Not to mention the insecticides, formaldehydes, and other toxins that come in contact with the tree in nature. Exposure  to  dust  containing  any  of  these  can  cause respiratory ailments, allergic reactions, skin problems, and liver, kidney, or blood diseases. Keep in mind, the finer dust particles can be easily inhaled and ultimately end up within the bloodstream. These are the realities as pertaining to proper dust collection in the modern workshop. DESIGNINGTHEPROPERDUSTCOLLECTIONSYSTEM FOR YOUR SHOP In  order  to  design  a  cost-effective  and  efficient  dust collection system, the ducting must be carefully planned. The simpler the system, the cheaper and more efficient it will be. Before getting started, there are many variables which should be considered, such as:  type of dust collector, type of ducting material, location, layout, and the budget for your system. Dust Collectors There are basically two types of dust collectors: single- stage, and two-stage. A single-stage unit is an inherently cheaper system which consists of an inline impeller which passes debris through the impeller and deposits the dust and debris into a filter bag. As dust and debris collects in the bag or drum, the system becomes increasingly less efficient. Precautions need to be taken with single-stage systems to prevent large objects, or any objects that can cause sparks when passing through the impeller. Objects that are too large can cause damage to the impeller, thus resulting in impaired  performance.  Objects  that  cause  sparking exponentially increase the chance of a fire or dust explosion. A good dust separator should be installed so that it will trap metal objects before they reach the impeller. If you suspect a spark was generated, the unit should be shut down immediately and the bag emptied into a safe airtight container. Two-stage units draw dust and debris into the system, but  deposit  the  majority  of  the  debris  in  the  first  stage collection  container  before  entering  the  impeller.  At  this point, only fine dust passes through the impeller. As this fine dust passes through the impeller, the second stage consists of a fine micron filter element which filters the fine dust as the air is exhausted from the dust collector back into the shop. Choosing Piping There are two types of piping to choose from: metal or plastic. There are several different types of metal ducting such as stove, heat, and ventilation piping, as well as piping designed  specifically  for  dust  collection  systems.  Metal piping  is  generally  more  expensive,  but  has  many advantages over plastic piping. One advantage of using metal piping is the fact that it is a conductor and does not contribute  to  static  electrical  charge  build-up.  Although suspended dust within the ducting still generates a static electrical charge, metal piping is a conductor that can be easily grounded, dissipating the charge. If metal piping is to be used for the system, it should be of 26 gauge material or heavier  so  that  the  ducting  will  not  collapse  from  the vacuum.  The  ideal  ducting  is  piping  that  is  specifically designed for dust collection purposes because it is the most efficient;  however, this is the most expensive. The use of metal piping does make installation more difficult, and may not  be  airtight  if  it  is  not  specifically  designed  for  dust collection.  All  leaks  should  be  sealed  for  optimum performance. Plastic piping, such as PVC or ABS, is the least expensive, readily available and easily assembled, but it has many inherent problems. Plastic piping is an insulator; thus static electricity is generated as dust particles travel through the ducting.  It  is  very  important  to  ground  a  plastic  ducting system in order to dissipate the static electrical charge. This can  be  accomplished  by  running  bare  16  AWG  copper grounding wire, which should be stranded, braided and run inside  the  entire  ducting  system  (braided  antenna  wire works well too). At any joints, the wire should be soldered