Note: Descriptions are shown in the official language in which they were submitted.
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DOOR SEAL
sackground of the Invention
The present invention relates to a new and improved
seal for a door on a combustion chamber of a fluid heater
or boiler and to the method for sealing the door and to
the kit that may be used to seal the door.
Most combus-tion chambers of fluid heaters include a
rear door at the opposite end of the combustion/heat
exchanger structure to allow access for service and
assernbly. During operation of these prior art heaters
over a substantial length of time, the refrac-~ory in the
rear door deteriorates due to the intensity of radiation
and the impingement of combustion products. This deteri-
oration results in the loss of refractory and poor per-
formance of the unit due to increased heat losses in the
area of the door. It is desirable that this deteri-
oration of the refractory in the door and resultant heat
loss be eliminated or substantially reduced. In
addition, it is also desirable that a kit or similar
device be available such that doors on existing heaters
can be sealed in order to avoid deterioration of the
refractory and resultant heat loss.
Surnmary of the Invention
The object cf the present invention is to provide a
new and improved device for sealina a door in a combus-
tion chamber of a fluid heater.
Another ob~ect of the present invention is to provide
a new and improved method for sealing a door in a
combustion chamber of a fluid heater.
~ still further object of the present invention is to
provide a new and improved kit for sealing doors on
existing combustion chambers in fluid heaters.
Briefly, the present invention is directed to a new
and improved seal for sealing an access or rear door in a
2 --
combustion chamber of a fluid heater. The seal incll~des
a gasket to which is applied adhesive material. A preferred
form of gasket is a preformed ceramic fiber gasket. The
gasket is then secured to the interior surface of the access
door after adhesive material has also been applied to the
surface. An observa-tion port may be cut in the gasket if
an observation port exists in the door.
srief Description of the Drawing
The above and other objects and advantages and novel
features of the present invention will become apparent
from the following detailed description of a preferred
embodiment o~ the invention illustrated in the accompa-
nying drawing; wherein:
FIG. 1 is a vertical, cross-sectional ~iew of a fluid
lS heater including a door sealed .in accordance with the
principles of the present invention;
FIG. 2 is a reduced, partially schematic view of an
access door on the fluid heater illustrated in FIG. l;
FIG. 3 is a partial view of the door illustrated in
FIG. 2 with the seal applied thereto; and
FIG~ 4 is a view similar to FIG~ 3 with an obser-
vation port provided therein.
FIG. 5 is a detailed section of circled portion 5 of
FIG. 1, showing the seal and rear door in place.
Description of the Preferred Æmbodiment
Referring initially to FIG. 1 there is illustrated a
fluid heatPr generally designated by the reference
numeral 10 of the type described in United States Patent
NoO 3 9 282~257. The device of the present invention is a
seal intended to seal the rear access door on a combu5-
tion chamber employed in a heater of the type described
in United States Patent No. 3,282,257. Accordinglyt the
fluid heater 10 will only briefly be described with ~he
understanding ~hat a more complete descrip~ion of the
fluid heater 10 may be obtained by reEerence to the above
noted patent.
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--3--
The fluid heater 10 lncludes a heat exchanger gener-
ally designated by the reference numeral 12 that includes
a burner 14 and a coil housing 13. Not shown in FIG. 1
is a steam separating drum employed when said heater is
used as a steam generator, that is connected -through a
manifold to a plurality of outlet water tubes 16, 18, 20
and 22. The outlet water tubes 16, 18, 20, and 22 are
connected to a bank of water tubes generally designated
by the reference numeral 24 that in turn are connected to
inlet water tubes 26, 28, 30 and 32. The inlet water
tubes 26, 28, 30, and 32 are in turn connected to an
inlet manifold 34. The inlet maniold 34 is in turn
connected to a recirculating water pump (not shown~
through a pipe 36.
As will be readily understood by those skilled in the
art, if the heater is used with high boiling point heat
transfer liquids, this flow direction would be reversed.
Liquid heating without entering the vapor phase is best
accomplished by introducing the lowest temperatur~ on
return liquid where it comes in contact with the highest
temperature combustion gases.
In steam generator operation, the hot combustion
gases generated by the burner 14 are forced through a
center opening 38 in the bank of water tubes 24 and radi-
ally outwardly to wipe across the surfaces of the water
tube coil counter to the flow of the water through the
coils and into a flue gas collection chamber 40 and from
there into a stack connection or fitting 42 and out a
stack connected thereto. The combustion products that
pass from the burner 14 through the opening 38 impinge on
and heat a rear door generally designated by the
reference numeral 44. The rear door 44 is connected to a
hinge 48 that is mounted on the housing 13 by a pivot
hinge mechanism generally designated by the reference
numeral 50. The inner surface of the door 44 is covered
by bxick or refractory material 52. The refractory mate-
rial 52 abuts against an annular ring of firebrick 54
mounted within the housing 13. In the closed position (FIG.
1) the refractory material 52 abuts against the firebrick
5~.
Typically, in the prior art the firebrick 52 is
subject to high temperatures and the impingement of combus-
tion product resulting in deterioration of the refractory or
firebrick 52. It is this surface that is desired to be
sealed in order to protect it from these deliterious
effects. This surface is sealed by a deformable preformed
ceramic fiber pad or gasket 56 that is secured to the sur-
face by an adhesive such as ceramic fiber coating cement
such as Carborundum's "FIBERFRAX". The gasket or pad may be
a Fiber Frax Locon felt pad that is 8 lbs/ft3 and one and
one-half inches thick. Fiberfrax is the reyistered trade
mark of The Carborundum Co, Insulation Division, Niagara
Falls, N.Y. The door 44 and specifically the surface 52 is
first cleaned in preparation for the application of the
gasket 56. Thereafter the surface 52 may be coated with the
adhesive cement using a brush9 One side of the preformed
ceramic gasket pad 56 is also coated with the adhesive
cement and the coated surface of the gasket pad 56 is then
placed upon the coated surface 52. The corners of the
gasket pad 56 may be secured to the door 44 by pieces of
masking tape 58 in order to hold the pad securely, and
prevent interference between the door closure 44 and the
firebrick 54.
After the pad 56 has been placed on the surface 52
and secured thereto by the masking tape 58, the door 44 may
be closed and locked to assure proper setting of the seal.
Closing the door/seal assembly provides a self adjusting,
insulating, gas tight seal intermediate adjacent and mating
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peripheral surfaces of the door and combustion chamber
(reference FIG. 1 and 5). It should be noted that, as parti-
cularly shown in FIG. 5, applicant's discovery that utiliz-
ing a deformable preformed ceramic fiber material positioned
between the combustion chamber refractory 54, and refractory
door surface 52, essentially establishes a labyrinth seal
between the far end of the combustion chamber pexiphery and
door mating surface. As indicated above, prior attempts at
utilizing refractory cement in this type of seal were
largely unsatisfactory, due to the inability of the cement
to retain sufficient resilience during high temperature
operation of the boilerO As will be well known to those
skilled in the art, expansion and contraction of the adja-
cent refractory surfaces requires that a seal follow or
expand and contract to fill voids created.
If the door 44 includes an observation port, an
observation port 60 may be cut into the pad 56 as illus-
trated in FIG. 4.
Use of the unit disclosed ~or heating fluids other
than water such as low vapor pressure thigh boiliny point)
petroleum base heat transfer liquids is also contemplated.
This so-called ~ uid phase" hea~ing wherein the heating
fluid is not allowed to change phase as in boiling results
in nearly identical refractory temperatures. Therefore, the
invention disclosed provides equivalent advantages for a
wide range of fluid heating applications.
