|
|
|
|
|
 |
Major advances have been made in vacuum filtration
in recent years, but all filtration is still a compromise. On the one hand,
vacuums require maximum air flow for maximum cleaning; the more air that
moves, the more dirt can be removed. On the other hand, dirt needs to be
separated from the air, and removing dirt usually means 'straining' it through
a filter. This impedes or even strangles air flow.
Fortunately, SuperVac's centralized architecture and advanced filtration
allow maximum airflow.
In conventional vacuum cleaner designs, bags stop visible dirt from being
blown back into the room after the vacuum has picked the dirt up from the
floor. Air and dirt entered the vacuum bag; the dirt stopped and the air
continued through the bag and back into the home.
SuperVac™ does not use bags. You simply empty the SuperVac™ dirt
receptacle 2 or 3 times a year.
Today we know the portable or canister vacuum bag allows microscopic, harmful
particles to pass through primary filtration with the air. The industry
is developing better vacuum filters to capture the tiny, invisible particles
as well as the bigger, visible ones. See HEPA
filters below.
Fortunately, central vacuums avoid blowing air back into the home by their
design . Instead, exhaust air is blown outdoors if the vacuum is properly
vented. So why does SuperVac™ even need filters?
- To protect the fans and motor from a dust buildup
that could shorten motor life.
- To remove visible dirt before it can be blown
outdoors in an unsightly way.
SuperVac has two filtration stages; dual-cyclonic and
a secondary cartridge filter.
In dual cyclonic filtration, air is forced into a cyclone-like swirl as
it enters the round vacuum canister. The air swirls down in the canister.
At the bottom of the swirl, over 95% of dirt falls to the floor of the dirt
container. As it falls, it passes through the separator cone, which prevents
the swirl from reaching to the bottom. Then the air moves upward toward
the vacuum exhaust, in a second swirl inside the outer downward swirl.
As the air is being exhausted, it passes through a second type of filtration,
the cartridge filter. Here finer remaining dust is captured before it can
be exhausted outdoors.
There have been many advances in filter media, and the thermoplastic cellulose
used in Hayden cartridge filters has been chosen because it allows greatest
airflow, while still capturing fine dust.
The Hayden cartridge filter media is pleated, to increase the filtering
surface area and thus airflow. The Hayden standard filter is over 7 square
feet, 3 times the size of the cloth filter bags common in many central vacuums;
and 8 to 15 times the size of the filter area in portable vacuums.
The cartridge filter doesn't need to be cleaned very often because the dual
cyclonic filtration has already removed most of the dirt.
A word about HEPA filters.
Most vacuum manufacturers offer some version of 'HEPA' filtration |
- HEPA stands for High Efficiency Particle Arrestor,
and a HEPA filter can remove many of the invisibly-small particles found
in indoor air.
- HEPA filters are found in industrial clean rooms
and hospitals where they are typically used in several hundred square
foot sizes. We would not have today's computer chips without HEPA filters
to remove particles that would otherwise contaminate the manufacturing
process.
- HEPA filters can be brittle, and can break when
pleated or when knocked around inside a portable vacuum in use. Tests
in the filter industry found HEPA filters often leaked because their
seal was imperfect.
- HEPA filters cannot be effectively cleaned so
they must be replaced, and they can easily cost $100 or more.
- HEPA filters, to capture very small particles,
are made of several layers and have only very small air passages. Even
first installed, they greatly constrict airflow. A typical HEPA filter
has perhaps a third the airflow of a Hayden cartridge filter. When they
get dirty, and choke airflow even more.
- Many filters are advertised to sound as if they're
HEPA when they're not. "HEPA-like" is not HEPA
|
|
In typical indoor air, almost half
of the respirable particles are so small they'll pass through a HEPA filter,
and back into the home's indoor air. With a good central vacuum, the particles
are blown harmlessly outdoors.
|
|
