Pipe joints or couplings – Packed – Wedge
Reexamination Certificate
1999-11-29
2001-02-27
Browne, Lynne H. (Department: 3629)
Pipe joints or couplings
Packed
Wedge
C285S110000
Reexamination Certificate
active
06193285
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a duct joining system, and more particularly to a duct joining system that provides an air-tight seal and that fastens the ducts together.
BACKGROUND
Air ducts, such as that used with central furnaces and air conditioning units and the like, are typically made from sheet metal or a plastic flexible material having cylindrical, rectangular, or other cross sections as are well known in the art. The ducts are conventionally joined by sliding an end of one duct into an end of another duct and fastening and sealing the joint with duct tape, fasteners and/or other sealants. Often ducts are joined to one another or to an air conditioner/heater unit or a vent using a fitting in a similar manner.
Unfortunately, over time the seal fails and air is permitted to escape from the duct joint. In many cases the mechanical connection is partially or fully broken. Thus, air from the duct system leaks into areas of the building where the air is neither intended nor desired, such as in the attic, basement, or between the walls. Consequently, the energy that was used to heat or cool the escaped air, in addition to the energy used to move the escaped air, is wasted.
Attempts to prevent the unintentional leakage of air from duct joints include placing a gasket between the two ducts. While gaskets prevent air from leaking out of the duct joints, the ducts still require some fastening mechanism to prevent the ducts from slipping apart during installation as well as over time. Thus, it is good practice to securely fasten the joints of a duct together, and in fact the Uniform Mechanical Code §602.4 requires a mechanical connection between joints. Sheet metal screws or other similar fasteners are sometimes used to prevent partial or complete disconnection of the ducts and to meet the requirements of the Uniform Mechanical Code. However, the installation of the duct system requires holding ducts in place while fastening the joints, which can be awkward and time consuming and is often simply not done, particularly when the installer is uninformed or is in a hurry. Consequently, many duct joints are held together with nothing more than duct tape, which quickly fails permitting partial or complete disconnection of the ducts.
Thus, there is a need for a duct joining system that quickly and easily fastens and seals ducts together to form an air-tight conduit.
SUMMARY
A duct joining system for providing an air-tight and mechanical connection includes a flexible gasket affixed to a male end of a first duct at an angle relative to normal of the male end of the duct. The female end of a second duct includes a raised bead in which the flexible gasket is seated when the ducts are properly joined together. The angled flexible gasket seated in the raised bead forms an air-tight seal as well as fastens or locks the joints together.
A stop bead on the first duct prevents the male end from being inserted too far into the female end. Thus, the ducts may be joined by simply inserting the male end into the female end until the female end contacts the stop bead. The male end also includes an indented portion near the flexible gasket to accommodate the flexible gasket while the male end is inserted into the female end. Thus, the flexible gasket will not interfere with the insertion of the first duct into the second duct.
A band clamp with a raised bead may be used to clamp the female end of a duct, particularly a flexible duct, over the male end of the first duct. The flexible gasket is thus seated in the raised bead along with the flexible duct, thereby forming an air-tight seal and a fastened connection.
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Brochure from SPIRO for SPIROsafe duct system, 1996 (two pages).
Browne Lynne H.
Dunwoody Aaron
Halbert Michael J.
Ogonowsky Brian D.
Proctor John P.
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