Product Range - Basic Operating Principles
Basically, our Controlled Pyrolysis Cleaning Furnaces
operate as follows.
 With the furnace empty, the afterburner
temperature is set to idle at approximately 870°C with the
furnace temperature at 370-540°C. The afterburner idle
temperature remains relatively constant due to a fixed air
and gas flow rate. There are no modulating gas valves or air
shutters on the afterburner. The air shutter is fixed at one
position and an orifice plate with a fixed incoming gas
pressure controls the gas flow rate. Thus, the afterburner
idle temperature is fixed.
When the furnace is loaded with
parts coated with cured paint, cured polymer, cured varnish,
or other organic material, this material will not start to
decompose until it reaches a temperature of about 315°
-370°C. When the material starts to decompose into smoke,
this smoke enters the afterburner chamber where it burns and
raises the temperature of the afterburner exhaust gases.
When enough smoke is entering the afterburner chamber to
drive the exhaust gas temperature up to its set point of
930°C, the furnace water sprays are activated to cool the
furnace and the parts and slow down the evolution of smoke
to the afterburner. This prevents overwhelming the
afterburner with large amounts of smoke and also prevents
the parts from catching on fire inside the furnace. Thus,
when smoke is actually being evolved off of the parts, the
afterburner temperature will operate at approximately 930ºC |
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The maximum amount of smoke allowed to enter the
afterburner chamber is limited to the amount that will raise
the afterburner temperature to 930ºC. Thus, the rate at
which the furnace will process the organic material off of
the parts is limited by the size of the afterburner. This
Controlled Pyrolysis system is unique to our technology and
is the subject of two patents. The afterburner chamber and
the exhaust stack volume insure that the exhaust gases are
maintained at a temperature at or above 930ºC for the
required minimum ½ to 2 second. When all of the organic
material has been removed from the parts, the afterburner
temperature will drop back down to its idle point of about
850ºC. At this point, the furnace typically runs for an
additional 1 or 2 hours in order to remove any remaining
residues on the parts. The furnace control system is
electrically interlocked so that the furnace can not run
unless the afterburner is operating. |
Inorganic materials such as the titanium dioxide pigment in some
paints, glass fibres, sand, etc., can not be removed by the furnace
since they are inorganic and will not burn. If present, these inorganic
materials either drop off of the parts and into the floor of the
furnace, or they may remain behind on the parts themselves as an ash
residue. It is generally possible to remove the remaining ash residue by
simply wiping or washing it off the parts after the cleaning cycle is
over, as the organic binder holding the material together will have been removed
during
the cleaning process.
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