"Clean-Air" Upright Design & Benefits
An upright type of vacuum cleaner is
a self-contained unit which has the motor,
main cleaning nozzle, filtering system, etc.
all built together in an overall vertical shape. All upright types today
have motor driven revolving brush rolls and
are used primarily for cleaning carpeted floors. They are pushed forward
and pulled backward in front of the user by gripping the narrow handle
extending upward from the main case.
The general upright type can be subdivided into three basic types
having three unique design characteristics. They are the
Traditional Upright, the "Clean-Air" Upright
and the Two-Motor Upright. The
"clean-air" upright design has been around for many years, originally
introduced by The Hoover Company with their
innovative Dial-a-Matic series.
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Main Characteristics of the "Clean-Air" Upright |
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The "clean-air" upright designation is used since the air which passes
through the suction producing fan or fans is
already "clean", having passed through most of the
filtering system before reaching it. While
two-motor uprights usually fit this description as well, this designation
typically is used to refer to an upright using only one motor to create the
suction and drive the brush roll. As such, it is often used when comparing
"clean-air" uprights to "dirty-air" (traditional) uprights.
The air enters the nozzle near the floor and travels toward the paper
or cloth filter bag, carrying the dirt with it. The bag retains most of
the dirt and dust while allowing the air to pass through its filter media.
The air then travels through a filter pad to be cleaned further before
entering the high speed suction fan or fans. Since the air is quite
clean, it is allowed to flow through the
motor to cool it. After leaving the motor the air is often filtered by
additional exhaust filters to remove even more fine particles and carbon
from the motor brushes before it leaves the
vacuum cleaner.
The "clean-air" upright combines a canister
type motor and filtration system in the main body with a more
traditional type nozzle for cleaning carpeted floors. The basic vertical
configuration of the upright is maintained while performance with the
attachments is improved. Most uprights having this design conveniently
carry the attachments on-board with the hose always attached and ready to
use.
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Performance with Attachments |
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The canister motor design creates significantly more actual
suction (pressure difference) than the
traditional upright motor design. This is important for effective cleaning
with a hose and attachments due to the higher
resistance to air flow present in the hose. The velocity of the
air flow plus the amount of the carpet
agitation determines how well a vacuum
cleaner will pick up the dirt so the shorter the distance the air travels
and the larger the air passages, the better the performance will be.
Some "clean-air" uprights pull all the air through a long hose even when
cleaning with the main carpet nozzle, reducing their performance. For
more about suction motor and fan designs, see our articles on
Suction Motor Design & Operation and
Fan or Impeller Types & Performance.
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Increased Motor Protection |
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In addition to better performance with attachments, the "clean-air"
upright tends to have a significantly better track record than many
"dirty-air" uprights when it comes to fan and motor problems. The
manufacturers of "dirty air" uprights with on-board attachments often
use a high speed, small diameter fan to help overcome the lower suction
produced by that design. This often can have the adverse effect of
unusually high fan breakage rates and motor failures, especially when
the motor's amperage is higher than
about nine amps.
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Examples of Efficient "Clean-Air" Uprights |
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A number of companies are manufacturing uprights with the "clean-air"
design that are sold in the U.S.A. Some examples of this type of upright
are the Lindhaus HEALTHCAREpro HEPA,
SEBO X5 and
X4,
Miele S184 Powerhouse and
Panasonic MC-V5745 Powerwave and,
Hoover U6436-900 Self Propelled WindTunnel. The
current Eureka uprights use the "clean-air"
design. Ironically, Hoover, the originator of this
design, stopped making "clean-air" uprights for many years until their recent
introduction of the "WindTunnel" clean-air upright
series. Their focus has been more on carpet cleaning ability than attachment
cleaning performance so they have preferred the "dirty-air" design. Their
lower powered motors have less risk of fan breakage. Although Hoover's
efficiency ratings on their "dirty-air"
machines are in the seventeen to twenty-two range, the actual
amperage ratings are less
than eight. Their new "WindTunnel" clean-air upright is rated at 12 Amps. Their tests with it demonstrate that it outperforms their "dirty-air"
machines. For more about these ratings, see our articles on the
Power of the Suction Motor and
Hoover's Efficiency and Performance Ratings.
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Identifying "Clean-Air" Uprights |
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In summary, "clean-air" uprights typically produce better performance
when using on-board attachments. They also have significantly longer fan
and motor lives compared to most "dirty-air" uprights with on-board
attachments. Operating noise levels are typically much lower than from
their "dirty-air" counterparts. This design can be identified by looking
at the filter bag and the supporting container. If the paper bag is
supported by a flexible outer cloth or vinyl bag you can be sure that it
is the "dirty-air" design. If the bag is supported by a rigid enclosure,
open it and look for seals around the edges. If none are present, it is
probably the "dirty-air" design as well. If the rigid bag enclosure is
sealed and a foam or fiber filter pad is at the bottom of the enclosure,
it is probably the "clean air" design.
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