©1997, AMERICAN HAKKO PRODUCTS, INC.
ALL RIGHTS RESERVED
7
THEORY OF OPERATION.
The HJ3100 is a
high-mass flow, low-vacuum
system, which means that it depends upon air flow across the work area for
effective fume extraction. Contaminated air is captured from the workplace surrounding the soldering station by the hood
or hoods, and transferred to the HJ3100 by flexible or rigid ducts. Within the HJ3100, two filters, comprising three stages
of filtering, remove the contaminants from the air. The purified air is then returned to the area where the HJ3100 is
located.
Because the HJ3100 depends upon mass flow for its operation, free flow of air must be guaranteed between the station
where fumes are to be extracted and the main filter unit. The maximum length of flexible duct recommended for greatest
efficiency is 25 feet of unimpeded 3" duct. The maximum length of rigid duct is not significant, as this duct does not
materially restrict air flow.
F
ILTERING
.
There are three stages of filtering (Figure 1, below, illustrates the Hakko filtering process):
¾
The
pre-filter
is made of a treated polyester material. It removes coarse particles, such as dust, that may be
suspended in the air, and thus extends the service life of the HEPA filter. Particles as small as 30 microns diameter
are trapped by the pre-filter. It should be checked at least once a week, and replaced when clogged. Under normal
conditions
3
this will be every two to three weeks.
¾
The
main HEPA/carbon filter
purifies the air in two ways:
•
The
HEPA filter
is a special case of a particulate filter. It incorporates a pleated fiberglass paper medium, thus
providing the greatest amount of surface area within the volume of the filter case. It is rated as a 'hospital grade
HEPA filter' - greater than 98% efficiency per the DOP test - and removes particles as small as 0.3 micron.
•
The activated carbon filter adsorbs gases and odors from the filtered air. Adsorption efficiency is 80%.
•
The main filter should be changed every four months or 640 hours of use, whichever comes first.
¾
The
carbon filter
adsorbs gases and odors from the filtered air at an adsorption efficiency of 84%. It has a much
larger surface area than the carbon portion of the standard HEPA/carbon filter, hence a longer life. It should
always be used with a pre-filter to preclude being clogged by particulate matter.
¾
The particulate filter removes particles of 1 micron diameter and larger from the air. See page 5.
3
Normal conditions’ - Defined as single-shift operation, eight hours per day, five days per week.
Figure 1a. Figure 1b. Figure 1c.
The standard Hakko filter. The Hakko activated carbon filter. The Hakko particulate filter.
incoming
air
exhaust
air
HEPA/carbon
activated
pre-filter
filter
carbon
incoming
air
pre-filter
cellulose
exhaust
air
(optional)
filter
incoming
air
exhaust
air
carbon
pre-filter
activated
filter
