U.S. patent application number 11/106047 was filed with the patent office on 2006-10-19 for heat exchanger clean-out plug assembly.
This patent application is currently assigned to Burnham Services, Inc.. Invention is credited to Everett E. James, Joseph G. III Leszek, Gerald M. Rausch, Michael A. Sharkozy, Albert J. Wajda, Donald W. Zimmerman.
Application Number | 20060231088 11/106047 |
Document ID | / |
Family ID | 37107287 |
Filed Date | 2006-10-19 |
United States Patent
Application |
20060231088 |
Kind Code |
A1 |
Sharkozy; Michael A. ; et
al. |
October 19, 2006 |
Heat exchanger clean-out plug assembly
Abstract
A flue-gas to air heat exchanger having a flue-gas containing
shell with a heat exchange surface, flue-gas inlet and outlet
sections, and at least one tubular clean-out fitting is provided
with a removable plug having an outer peripheral portion
resiliently engageable with a section of the inner peripheral
portion of the fitting adjacent the shell. The plug periphery is
expanded into gas-tight sealing contact with the fitting inner
periphery by means affording installation and removal without
tools.
Inventors: |
Sharkozy; Michael A.; (North
Judson, IN) ; James; Everett E.; (Winamac, IN)
; Zimmerman; Donald W.; (North Judson, IN) ;
Wajda; Albert J.; (Knox, IN) ; Rausch; Gerald M.;
(Winamac, IN) ; Leszek; Joseph G. III; (North
Judson, IN) |
Correspondence
Address: |
HOWSON AND HOWSON
SUITE 210
501 OFFICE CENTER DRIVE
FT WASHINGTON
PA
19034
US
|
Assignee: |
Burnham Services, Inc.
Wilmington
DE
|
Family ID: |
37107287 |
Appl. No.: |
11/106047 |
Filed: |
April 14, 2005 |
Current U.S.
Class: |
126/307R |
Current CPC
Class: |
F23J 3/026 20130101 |
Class at
Publication: |
126/307.00R |
International
Class: |
F23J 13/02 20060101
F23J013/02 |
Claims
1. In a flue-gas to air heat exchanger having a flue-gas containing
shell with a heat exchange surface, said shell having flue-gas
inlet and outlet sections and at least one tubular clean-out
fitting having an inner peripheral portion of a predetermined
length extending away from said shell to afford access to the
interior of the shell for cleaning the shell interior, the
improvement comprising: a removable plug having an outer peripheral
portion resiliently engageable with a section of the inner
peripheral portion of said fitting adjacent said shell, and means
for expanding said plug section into gas-tight sealing contact with
said fitting inner periphery.
2. Apparatus according to claim 1 wherein said plug includes a
resiliently deformable tubular body having opposite end surfaces, a
distal disc engaging one of said body end surfaces and extending
transverse to said fitting, a proximal disc engaging the other of
said body end surfaces and extending transverse to said fitting,
and means for urging said discs axially toward one another for
peripherally expanding said tubular body into sealing engagement
with the inner periphery of said fitting.
3. Apparatus according to claim 2 wherein said proximal disc is
larger than said distal disc and extends across the outer end of
said fitting, and said tubular body is coextensive with a
substantial portion of said predetermined length of said
fitting.
4. Apparatus according to claim 3 where said means for expanding
said tubular body includes a rod extending axially through said
proximal disc, and means adjacent said proximal disc for tensioning
said rod axially and thereby effecting said expansion of said plug
body.
5. Apparatus according to claim 4 wherein said means for tensioning
includes threads on said rod extending through said proximal disc,
and a nut engageable with said threads and rotatable relative
thereto in engagement with said proximal disc.
6. Apparatus according to claim 5 including a hand grip carrying
said nut to afford manual turning thereof.
7. Apparatus according to claim 2 wherein said plug body is of
heat-resistant elastomeric material.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to heat exchangers, and more
particularly, the present invention relates to flue-gas to air heat
exchangers having clean-out access openings.
BACKGROUND OF THE INVENTION
[0002] Flue gas to air heat exchangers are used in hot air furnaces
to transfer heat from a combustion chamber to air flowed across the
heat exchanger surfaces for downstream distribution into an area to
be heated. One example of such a heat exchanger is a shell having a
hollow wall surrounding a combustion chamber to provide a
substantial surface area for heat transfer. The shell is connected
to the combustion chamber via a short pipe at one location, and the
shell is connected to a flue ring at another location. Hot
combustion, or flue, gases flow in a serpentine pattern through the
shell between the combustion chamber outlet pipe and the flue ring.
Over the course of time, soot from the combustion gases can form in
the shell, thereby necessitating cleaning.
[0003] In one model of such a furnace, a pair of access openings
are provided in the shell at spaced locations near where the air is
admitted to the heat exchanger. To afford access to the interior of
the shell, the openings have tubular extensions, and caps are
provided for the extensions remote from the heat exchanger shell.
While this structure has certain advantages, it has certain
limitations in that the extensions can accumulate soot and
condensate, which, over time, may cause corrosion under certain
conditions of use. Moreover, if the heat exchanger is not serviced
regularly, even the extension caps can become difficult to remove
and replace.
OBJECT OF THE INVENTION
[0004] The present invention overcomes the aforementioned
limitations by providing a shell heat exchanger access tube with a
plug that is capable of being removed and reinstalled readily
without tools to afford access to the heat exchanger shell interior
for periodic cleaning.
SUMMARY OF THE INVENTION
[0005] More specifically, a flue-gas to air heat exchanger having a
flue-gas containing shell with a heat exchange surface, flue-gas
inlet and outlet sections, and a tubular clean-out fitting having
an inner peripheral portion of a predetermined length extending
away from the shell to afford access to the interior of the shell
for cleaning the shell interior is provided with a removable plug
having an outer peripheral portion resiliently engageable with a
section of the inner peripheral portion of the fitting adjacent the
shell, and means for expanding the plug section into gas-tight
sealing contact with the fitting inner periphery. Preferably, the
plug includes a resiliently deformable tubular body having opposite
end surfaces, a distal disc engaging one of the body end surfaces
and extending transverse to the fitting, a proximal disc engaging
the other of the body end surfaces and extending transverse to the
fitting, and means for urging said the discs axially toward one
another for peripherally expanding the tubular body into sealing
engagement with the inner periphery of the fitting. More
preferably, the proximal disc is larger than the distal disc and
extends across the outer end of the fitting, and the tubular body
is coextensive with a substantial portion of the predetermined
length of the fitting.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The foregoing and other objects, features and advantages of
the invention should become apparent from the following description
when taken in conjunction with the accompanying drawings in
which:
[0007] FIG. 1 is a perspective view of a heat exchanger having a
pair of clean-out plug assemblies embodying the present
invention;
[0008] FIG. 2 is a longitudinal cross-sectional view taken on line
2-2 of FIG. 1 showing one of the plug assemblies in an
installation/removal mode;
[0009] FIG. 3 is a view similar to FIG. 3, but showing the plug in
its operational mode;
[0010] FIG. 4 is a transverse cross-sectional view taken on line
4-4 of FIG. 2; and
[0011] FIG. 5 is a transverse cross-sectional view taken on line
5-5 of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0012] Referring now to the drawings, FIG. 1 illustrates a flue-gas
to air heat exchanger 10 incorporating a pair of clean-out
assemblies 12 and 14 embodying the invention. The heat exchanger 10
comprises an upright octagonal shell 16 adapted to be confined in
an outer housing (not shown) to form a air plenum around the shell
for enabling air to be heated as it flows upwardly in the direction
of the solid line arrows in FIG. 1 lengthwise of the shell 16 along
an outer heat exchange surface 16a of the shell 16 and interiorly
of the shell 16 along an inner heat exchange surface 16b. An
upstanding cylindrical combustion chamber 18 is disposed centrally
within the shell 16 and is connected as its lower end via an elbow
(not shown) to a fuel burner, such as a oil burner, (not shown)
having a nozzle section extending into an aperture 20 of a front,
or proximal, burner mounting plate 22. The shell 16 is hollow and
contains flow directing baffles. The upper end of the combustion
chamber 18 is connected by a short pipe 24 to the upper rear, or
distal, end of the shell 16. A flue ring 26 is connected to the
upper front, or proximal, end of the shell 16. Combustion or
flue-gases are flowed in a serpentine path in the direction of the
arrows shown in broken lines in FIG. 1 to exit the flue ring 26. As
the flue-gases flow, they transfer heat to the heat exchange
surfaces 16a, 16b, and thus by convection to the air flowed
upwardly along them, as shown in solid lines in FIG. 1.
[0013] Over the course of time, soot can accumulate inside the
hollow shell 16, thereby necessitating cleaning to maintain the
thermal efficiency of the heat exchanger 10. To this end, a pair of
tubular clean out fittings 30, 32 are provided in the shell outer
wall adjacent its lower end outer wall 18a. Each fitting, such as
the fitting 30, is tubular and extends horizontally outward from
the heat exchanger shell wall 16a a predetermined distance
determined by the location of a front furnace housing wall (not
shown). Thus, the elongate fitting 30 facilitates access by a
maintenance technician to the interior of the shell from a proximal
location adjacent the fuel burner in the front of the furnace
without having to remove the furnace housing. Heretofore, the open
ends of the fittings were simply capped.
[0014] To overcome the limitations noted, supra, the present
invention provides a plug assembly which is readily removable and
reinstallable without the need for tools, and which keeps soot and
potential corrosion from forming in the clean-out fittings.
[0015] As best seen in FIG. 2, the plug assembly 34 preferably
extends from a location adjacent to the shell wall 16a to the open
front end 30a of the fitting 30. The plug assembly includes a
distal disc 36, a proximal disc 38 of larger diameter than the
distal disc 36 for engaging the front end edge 30a of the fitting
30, and a resilient tubular body 40 extending axially of the
fitting 30 between and engaging at its opposite end faces 40a and
40b, the discs 36 and 38, respectively. When the discs are urged
axially toward one another, they expand the resilient body 40 into
gas-tight sealing engagement with the inner periphery of the
fitting 30 as shown in FIG. 3.
[0016] In order to expand the tubular body 40, a means is provided
to urge the discs 36 and 38 toward one another. For this purpose, a
machine bolt 42 extends axially between the discs 36 and 38 with
its head 42a engaging the distal side of the distal disc 36 and
with its threaded section 42b extending through the proximal disc
38. A nut 46 is molded into a hand grip 48 having finger lugs 48a,
48b for engaging the threads of the bolt 42.
[0017] When the hand grip 48 is rotated clockwise (facing the
handle FIG. 1) the axial end surface 46a of the nut engages the
proximal side of the proximal disc and tensions the bolt axially.
This causes the body 40 to undergo a peripheral expansion from the
position shown in FIG. 2 to the position shown in FIG. 3. When the
hand grip 48 is thus fully tightened it remains in place until
again removed for cleaning the shell in a known manner. Removal for
cleaning is effected by reversely rotating the hand grip 48 to
allow the body 40 to return to its relaxed state shown in FIG. 2,
and then pulling on the hand grip 48 axially to disengage the plug
assembly 34 from the fitting 30.
[0018] Preferably, the resilient body 40 is about three (3) inches
long and is fabricated of heat resistant elastomeric material such
as neoprene rubber reinforced with polyester cord and is capable of
withstanding temperatures in excess of 180.degree. F. Preferably,
the outside diameter of the tubular body is slightly less than the
inside diameter of the fitting. By way of example, for a fitting
having a nominal inside diameter of 2.0 inches, the tubular body
has an outside diameter of 1.93 inches in its relaxed state before
being compressed axially between the discs. This dimensional
relation provides satisfactory insertion and removal and controlled
expansion with minimal turning of the hand grip.
[0019] While a preferred embodiment of the present invention has
been described in detail, various modifications, alterations and
changes may be made without departing from the spirit and scope of
the present invention as defined in the appended claims.
* * * * *