Furnaces – Draft regulators – Fan exhaust
Reexamination Certificate
2001-08-15
2003-07-22
Lazarus, Ira S. (Department: 3749)
Furnaces
Draft regulators
Fan exhaust
C110S297000, C415S207000
Reexamination Certificate
active
06595146
ABSTRACT:
BACKGROUND OF THE INVENTION
(i) Field of the Invention
The present invention relates in general to blower housings used in furnaces to remove the products of combustion and particularly to the exhaust transition of the blower housing. The blower housing includes an integrally formed portion of the exhaust transition and is of a two-piece construction.
(ii) Description of the Related Art
Furnaces utilize a blower to induce a draft through the furnace to draw the heated air and the products of combustion through a heat exchanger and exhaust them through an exhaust pipe. The blower housings used in prior art furnaces are typically made of sheet metal and have an exhaust port that is rectangular. However, the exhaust pipe to which the blower exhaust port is to be connected is usually circular in cross-section. Therefore, to accomplish the transition from a rectangular exhaust port to a circular exhaust pipe inlet, a transition piece is attached to the blower housing that converts the rectangular exhaust port into a circular exhaust port that can be connected to the circular exhaust pipe. The transition piece has opposite first and second ends. The first end is rectangular and is adapted to be attached to the rectangular exhaust port on the blower housing. The second end is circular and is adapted to allow connection to a circular exhaust pipe.
The transition pieces are typically made of cast aluminum. Cast aluminum exhaust transition pieces are expensive to manufacture and increase the costs of the blower assembly and the associated furnace within which the blower assembly is utilized.
Additionally, the prior art exhaust transition pieces are often attached to the rectangular blower housing exhaust ports by screws. Usually, three or four sheet metal screws are used to attach an exhaust transition piece to the exhaust port of the blower housing. Because the exhaust transition piece is attached to the exhaust port for the blower housing by screws, the labor to attach the transition piece adds to the cost of the blower assembly. Furthermore, because the exhaust transition piece is only secured to the blower housing by three or four screws, the connection often becomes loose over time and the exhaust transition piece may rattle or produce undesirable noise when the blower is being run.
Therefore, what is needed is an exhaust transition piece that is less expensive to manufacture, less labor intensive to install, and reduces the possibility of rattling.
SUMMARY OF THE INVENTION
The present invention overcomes the shortcomings of prior art cast aluminum transition pieces by providing an exhaust transition having a portion that is integrally formed with the blower housing and is of a two-piece construction that is considerably less expensive to manufacture. The exhaust transition is also less likely to rattle and requires less labor to assemble.
The blower housing and exhaust transition of the invention is comprised of a blower housing body and a discharge pipe that is comprised of first and second sections. The first section of the discharge pipe is a part of the blower housing body and is a one-piece construction with the body. The second section of the discharge pipe is adapted and configured to attach to the first section of the discharge pipe to produce the tubular configuration of the pipe. The discharge pipe has first and second ends and a length between the ends. The first end of the discharge pipe is an inlet and is adjacent the body. The second end of the discharge pipe is an outlet and is generally circular in cross-section. When the second pipe section is attached to the first pipe section, the discharge pipe is formed and a circular outlet is created.
The inlet of the discharge pipe is generally rectangular in shape. The discharge pipe transitions from being generally rectangular in shape at the inlet to being generally circular in shape at the outlet. The transition is made progressively along the length of the pipe.
In variations of the blower housing and exhaust transition, the inlet is not always generally rectangular in cross-section. The blower housing may have a portion of the body adjacent the inlet that curves or bows outwardly from the body as the portion of the body extends towards the pipe inlet. With the body having a portion that curves outwardly as it approaches the inlet, the first discharge pipe section will also curve or bow outwardly from the body as it extends from its inlet end to its outlet end so that it is aligned with and complementary to the curved portion of the body. In essence, this configuration of the blower housing begins the transition to the generally circular outlet prior to the inlet to the discharge pipe.
The blower housing body is formed with front and back walls connected together by a generally volute sidewall. The back wall has an opening that leads to the interior of the body. The interior is defined by the front and back walls and the sidewall. The interior is configured and adapted to receive a fan which rotates within the interior and generates a flow of air through the housing. A throat in the body leads to the exhaust transition. The transition is comprised of first and second sections and forms an outlet through which the flow of air leaves the housing. The first transition section is formed as part of the body and creates a first portion of the outlet. The second transition section forms a second portion of the outlet and is complementary to the first transition section. The second transition section is configured and adapted to attach to the first transition section by crimping the second transition section to the first transition section.
The two piece blower housing and exhaust transition of the present invention overcomes the disadvantages of the prior art. The invention provides for one of the exhaust transition sections to be part of the body. This piece is formed when the body is stamped and is formed of the same material as the body. Additionally, the second piece is also preferably formed of the same material as the body. Because the body is typically made of sheet metal, the first and second pieces of the exhaust transition are also made of sheet metal, which is significantly less expensive than the prior art transition pieces which are made of cast aluminum. The two pieces of the exhaust transition can be attached to one another by crimping one to the other. The crimping provides for a tight connection that will resist rattling better than the prior art use of sheet metal screws in attaching the transition piece to the body. Finally, the process of crimping is less labor intensive and further reduces the costs of manufacturing the housing over that of the prior art.
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Jakel Incorporated
Lazarus Ira S.
Rinehart K. B.
Thompson & Coburn LLP
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