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AssigneeRite-Hite Holding Corporation
InventorsNicolas B. Paschke, Kevin J. Gebke
Estimating the term…
A fabric flow restriction and method for conveying a volume of air through a fabric duct prevents the violet popping that may occur with a fabric duct upon start-up. The fabric ducts are air permeable and/or include discharge openings that evenly disperse supply air from within the duct to a room being heated, cooled, ventilated, or otherwise conditioned by the air. The ducts are typically in a collapsed positioned prior to blower start-up. With the initial airflow, the ducts quickly fill with air and may make a popping sound at their distal ends as the airflow fills the entire fabric duct. The flow restrictions disclosed may be formed of a flexible fabric that has an airflow resistance that varies with radius across the flexible fabric. The flow restrictions may have a first region and a second region each with different resistances, for example. Varying the resistance across the fabric flow restriction reduces or eliminates the popping condition. The condition may also be eliminated by using a uniform resistance flow restriction that has a high resistance during start-up and a low resistance during normal operation.
An air duct assembly comprising:
For use in a fabric duct, a fabric flow restriction comprising:
A method of conveying a volume of air, comprising:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
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In the form of perforated plates: placed transversely
With forced air circulation, e.g. by fan positioning of a ventilator in or against a conduit: fan combined with single duct; mounting arrangements…
Ducting arrangements: flexible soft ducts, e.g. ducts made of permeable textiles
Outlets for directing or distributing air into rooms or spaces, e.g. ceiling air diffuser: perforated ducts
Term end not estimated
1. Field of the Invention
The subject invention generally pertains to fabric air ducts and more specifically to a damper for such a duct.
2. Description of Related Art
FIG. 1 is a front view with a partial cut-away showing a fabric air duct assembly that includes fabric flow restrictions.
FIG. 2 is a bottom view of FIG. 1.
FIG. 3 is a closer view of the cut-away portion of FIG. 1.
An air duct assembly 10, shown in FIGS. 1 and 2, includes several fabric ducts 12, 14, 16, 18 and 20 that are suspended within a building 22 by series of connectors 24, which hang from one or more elongated support members 26, such as a track or a taut cable. Several fabric flow restrictions 28, 30, and 32 help balance the volume of airflow through the ducts. An air handler 34, such as a fan or blower disposed within an enclosure, forces air 36 into a main duct 12. In this example, duct 12 consists of fabric; however, it could also be made of sheet metal or of another material. The term, “fabric,” refers to any pliable sheet of material that may or may not be air permeable or porous. Examples of a fabric include, but are not limited to, woven or knit cloth, flexible plastic sheeting that is not necessarily woven, plastic impregnated cloth, fiber reinforced plastic, and various combinations thereof.
Main duct 12 feeds air 36 into two branch ducts 14 and 18, which in turn feed air 36 into two other branch ducts 16 and 20 respectively. Thus, ducts 14 and 16 are in series-flow relationship to each other, and so are ducts 18 and 20. Duct 14 is in parallel-flow relationship with ducts 18 and 20 and so is duct 16. The term, “parallel-flow” refers to airflow being split between two different paths. Forced air 36 from air handler 34 or another source inflates each of the fabric ducts to a tubular shape, as shown. Porosity and/or other openings in the ducts' fabric allow the air within ducts 14, 16, 18 and 20 to disperse into a room or area that is being ventilated or otherwise conditioned by air 36. In some cases, main duct 12 may be air-permeable to disperse some air into part of the building as well.
Flow restrictions 28, 30 and 32 each have a flow resistance that has been individually set to apportion the airflow being discharged through the fabric wall of each of ducts 14, 16, 18 and 20. The term, “flow resistance” is a measure of a restriction's ability to create a pressure drop for a given volume of airflow through the restriction. Thus, for a given volume of airflow, a higher pressure drop is created by a restriction having a higher flow resistance. Likewise, for a given pressure drop across a restriction, a lower volume of airflow is conveyed through a restriction having a higher flow resistance. The flow resistance of a flow restriction can be set or adjusted by a variety of methods, depending on the structural design of the restriction.