Brushing – scrubbing – and general cleaning – Machines – With air blast or suction
Reexamination Certificate
2000-02-03
2002-08-13
Moore, Chris K. (Department: 1744)
Brushing, scrubbing, and general cleaning
Machines
With air blast or suction
C015S304000, C015S315000, C015S340100, C015S345000
Reexamination Certificate
active
06430772
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to duct cleaning equipment and relates, in particular, to a truck-mounted vacuum unit for cleaning the air ducts of houses and other structures.
BACKGROUND OF THE INVENTION
Houses and other buildings are commonly heated and cooled using a heating, ventilation, and air conditioning (HVAC) system. Such systems typically include a furnace for heating air. This furnace is attached at one end to a supply duct and at another end to a return duct. When the HVAC system is turned on, air moves from the interior of the house, through the supply duct, and into the furnace. The furnace then heats the air and returns the air to the interior of the house via a return duct.
Because, when activated, the HVAC system pumps dusty air from the interior of the house through the air ducts of the house, dust and other debris frequently accumulate on the interior of the air ducts. Such a buildup of debris can cause the quality of the air within the house to deteriorate because, as streams of air move through the ducts, debris from within the ducts may dislodge from the interior of the ducts and travel along with the air as the air flows through the ductwork and back into the house. This can adversely affect the health of those inhabiting the house.
To solve this problem, a technique has been developed for removing debris from within the air ducts of the HVAC system. This technique involves placing a suction source within the air ducts of the HVAC system, and then, while the suction source is activated, inserting a high-pressure air hose into the ducts upstream from the suction. The high-pressure air hose is then used to blow a stream of highly-compressed air within the ducts to dislodge debris from the interior surfaces of the ducts. The debris is then sucked into the suction source and removed from the interior of the duct.
To accomplish this technique, a duct-cleaning apparatus is generally used that has the following components: (1) a compressor; (2) an air hose for delivering compressed air from the compressor to the interior of the air ducts; (3) a suction source; (4) a suction hose for connecting the suction source to the interior of the air ducts; (5) a filtration system for filtering debris from the air that is removed from the air ducts; (6) a transportation platform for transporting the duct cleaning apparatus; and (7) a storage compartment for storing the air hose and suction hose during transportation.
To use the apparatus, a technician generally cuts a hole, sufficient to receive a suction hose, into one of the air ducts near the furnace. The technician then connects one end of the suction hose to the suction source and feeds the other end of the suction hose into the hole in the air duct. Next, the technician cuts one one-inch hole in the air duct approximately every ten feet upstream from the suction hose, and attaches a nozzle to the end of the air hose. The technician then turns the suction source on, which creates a suction within the duct, as will be discussed in more detail below. Next, the technician feeds the nozzle of the air hose through each of the one-inch holes and uses the air hose to dislodge debris from the interior of the air duct by spraying the interior of the duct with a stream of highly pressurized air. The airborne debris is then sucked into the suction source and removed from the interior of the duct. A filtration system then removes the debris from the air passing through the suction hose.
In order to use the air hose to remove debris from the interior of an air duct, a technician may perform either a forward or reverse “air sweep” within the duct. Before performing a reverse air sweep, the technician attaches a reverse air sweep nozzle to the end of the air hose. Such reverse air sweep nozzles include a series of jets that point back toward the air hose. After the suction source has been activated, the technician activates the air compressor and then feeds the air hose into one of the one-inch holes in the ductwork. The technician then gradually feeds the air hose upstream in the air duct in relation to the suction hose. As the air hose moves through the duct, the air hose blows air downstream against the sides of the duct and dislodges debris from the sides of the duct.
Before performing a forward air sweep, the technician attaches a forward air sweep nozzle to the end of the air hose. Such forward air sweep nozzles include a series of jets that point away from the air hose. After the suction source has been activated, the technician activates the air compressor and then feeds the air hose into one of the one-inch holes in the ductwork. The technician then gradually feeds the air hose downstream in the air duct in relation to the suction hose. As the air hose moves through the air duct, the air hose blows air downstream against the sides of the air ducts and dislodges debris from the sides of the duct.
Two different general types of duct cleaning apparatuses are currently known in the art. The first type of apparatus is a portable duct cleaner that comprises a small, portable gas-powered compressor and suction source that may be transported within the interior of a van to the building to be serviced. Once there, the portable duct cleaner is lifted from the van, wheeled into the building to be serviced and then used to clean the air ducts of the building. The disadvantage of these portable duct cleaners is that, because the duct cleaner must be small enough to fit into the back of a van, the size (and, therefore, power) of the portable compressor and suction source is limited. Also, because these portable duct cleaners tend to be heavy, two technicians are required to remove them from the transport van. A further disadvantage of these portable duct cleaners is that they are gas-powered, and therefore should not be operated within an enclosed space. One advantage of these portable duct cleaners is that, because they are small and capable of being moved within the interior of a building, they can be used to access hard-to-reach ducts.
A second type of prior art duct cleaning apparatus is a duct cleaning truck that comprises a large compressor and suction source mounted in a truck and powered by the power takeoff (PTO) of the truck. As shown in
FIG. 7
, the typical prior-art-duct cleaning truck has an array of inflatable cloth filters disposed beneath top doors that open to extend the air filters in operation. A storage compartment receives suction hose that must be coiled or bent to fit within the compartment.
This prior art duct cleaning truck has several disadvantages. First, because the prior art truck has a box-like storage space for storing long lengths of suction hose, a technician must bend or coil the suction hose before placing the suction hose into the storage space in order to fit the suction hose into the storage space. Over time, this may kink the suction hose and obstruct the air flow within the suction hose. Thus, the repeated coiling and bending of the suction hose over time may decrease the efficiency of the suction hose.
A second disadvantage of the prior art duct cleaning truck is that these trucks are only capable of storing 100-150 feet of suction hose. This is because storing the hose in a coiled position is not an efficient storage method. Also, because the coiled suction hose tends to take up a large portion of the storage space in the truck, the truck can not accommodate both 100-150 feet of suction hose and large tools, such as a boroscope or a portable duct cleaner, at the same time.
Another disadvantage of the prior art duct cleaning truck is that these trucks tend to fill with water when they are used in the rain. This is because, when a prior art truck is operated, the hinged top doors of the truck must be open to allow an array of inflatable cloth filters to expand above the truck, as shown in FIG.
7
. Because these filters are not waterproof, when a prior art truck is operated in the rain, rainwater tends to seep through the cloth filters and into the truck. Over time, this can cau
IAQ, Inc.
Kilpatrick & Stockton LLP
Moore Chris K.
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