U.S. patent number 3,683,867 [Application Number 05/091,439] was granted by the patent office on 1972-08-15 for boiler.
Invention is credited to Hans Viessmann.
United States Patent |
3,683,867 |
Viessmann |
August 15, 1972 |
BOILER
Abstract
A boiler with a boiler casing carrying a heat exchange medium
and a double wall bulkhead in the casing receiving the heat
exchange medium therefrom and defining a combustion chamber. A fuel
burner is arranged at the inlet of the combustion chamber and
produces gases. A double wall bulkhead having a baffle wall portion
opposite the inlet and two arcuate lateral wall portions extending
from the baffle wall portion towards the inlet also receives the
heat exchange medium from the casing and is positioned in the
combustion chamber to define a baffle chamber reflecting and
reversing the combustion gases to combustion gas conduits laterally
adjacent the lateral arcuately shaped bulkhead wall portions. The
baffle chamber and the lateral combustion gas conduits have the
same height, and an exhaust flue receives the combustion gases from
the conduits at the outlet of the combustion chamber.
Inventors: |
Viessmann; Hans (Battenberg,
Eder, DT) |
Family
ID: |
25758291 |
Appl.
No.: |
05/091,439 |
Filed: |
November 20, 1970 |
Foreign Application Priority Data
|
|
|
|
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Dec 27, 1969 [DT] |
|
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P 19 65 037.4 |
Jan 28, 1970 [DT] |
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P 20 03 690.2 |
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Current U.S.
Class: |
122/136R;
122/33 |
Current CPC
Class: |
F24H
1/50 (20130101) |
Current International
Class: |
F24H
1/50 (20060101); F24H 1/48 (20060101); F22b
007/00 () |
Field of
Search: |
;122/33,37,136,149 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Sprague; Kenneth W.
Claims
What is claimed is:
1. A boiler using a fluid fuel comprising
1. a boiler casing carrying a heat exchange medium,
2. a double wall bulkhead receiving the heat exchange medium from
the casing and defining a combustion chamber having an inlet and an
outlet opposite to the inlet,
3. a fuel burner arranged at the inlet and producing combustion
gases in the combustion chamber,
4. a double wall bulkhead having a baffle wall portion opposite the
inlet and two lateral wall portions arcuate in horizontal cross
section and extending from the baffle wall portion towards the
inlet, said bulkhead receiving the heat exchange medium from the
casing and positioned in the combustion chamber opposite the fuel
burner so as to define a baffle chamber reflecting and reversing
the combustion gases to combustion gas conduits laterally adjacent
the lateral arcuately shaped bulkhead wall portions,
a. the baffle chamber and the lateral combustion gas conduits
having the same height, and
5. an exhaust flue for the combustion gases arranged at the outlet
and receiving the combustion gases from the conduits.
2. The boiler of claim 1, further comprising an additional double
wall bulkhead receiving the heat exchange medium from the casing
and positioned between the first-named bulkhead defining the
combustion chamber and the second-named bulkhead defining the
baffle chamber, the additional bulkhead being interrupted in the
range of the exhaust flue.
3. The boiler of claim 2, further comprising a pair of horizontally
extending sheet metal walls interconnecting the bulkheads, the
sheet metal walls defining openings permitting the heat exchange
medium to enter the bulkheads from the casing.
4. The boiler of claim 1, further comprising a pair of further
double wall bulkheads receiving the heat exchange medium from the
casing, the further bulkheads being positioned within the baffle
chamber symmetrically laterally adjacent the arcuately shaped
bulkhead wall portions on either side of the fuel burner inlet.
5. The boiler of claim 4, wherein the further bulkheads extend
towards the inlet and adjacently thereto, leaving a gap between
forward ends of the further bulkheads and the inlet.
6. The boiler of claim 4, wherein the further bulkheads extend to
the inlet and their respective ends are spaced apart to define the
inlet.
7. The boiler of claim 1, wherein the further bulkheads are so
positioned in respect of the arcuately shaped bulkhead wall
portions that they define tapering combustion gas conduits.
Description
BACKGROUND OF INVENTION
The present invention relates to water boilers.
Boilers having a casing which conducts heated media, e.g., water,
and in which a combustion chamber is formed by a screen or wall
about which run heating gas flues are well known. To attain optimum
combustion values, a good intermixing of the combustion air with
the fuel, which may be oil or gas, in the burner or burner head is
absolutely necessary. Good intermixing is, for instance, obtained
if the blower of the burner produces a sufficiently high pressure.
Generally, it is possible to produce the desired pressure in the
combustion chamber only after a period of operation of the burner.
However, it is sometimes possible to design the burners in such a
way that from the very outset they produce a specific combustion
chamber pressure. In either event, the burners must be in a
position to overcome the particular thermal resistance in the
boiler before efficient operation is obtained. If the boiler is
consistently designed for excess pressure in the combustion
chamber, considerable economies in the heating surfaces are
obtained. This is particularly so if the boiler is correctly
designed from its flow aspect and if the ratio of combustion
chamber volume to the flues and in particular the heating surface
of the combustion chamber to the heating surface of the flues is at
a calculated ratio, as well as if the transfer cross-sections from
the combustion chamber to the flues are sufficiently large.
In combustion chambers of the known and conventional type, these
fundamental criteria are only taken into consideration with a
corresponding increase in production costs. In addition, special
cleaning ports are required, causing the fitting of the external
boiler insulation to be correspondingly costly. The arrangement,
coordination and design of combustion chamber and flues generally
do not permit the rapid welding of parts and substantially prevent
the automatic fabrication of the boiler into a unitary
structure.
It is, therefore, an object of the present invention to remove
these difficulties, i.e., to provide a boiler which, while taking
into account the above-indicated requirements, permits a simple and
therefore cost-saving manufacture. It is also an object of this
invention to provide a boiler carrying a head exchange medium. A
double wall bulkhead receives the heat exchange medium from the
casing and defines a combustion chamber having an inlet and an
outlet opposite to the inlet. A fuel burner is arranged at the
inlet and produces combustion gases in the combustion chamber. A
double wall bulkhead having a baffle wall portion opposite the
inlet and two arcuate lateral wall portions extending from the
baffle wall portion towards the inlet also receives the heat
exchange medium from the casing and is positioned in the combustion
chamber opposite the fuel burner so as to define a baffle chamber
reflecting and reversing the combustion gases to combustion gas
conduits laterally adjacent the lateral arcuately shaped bulkhead
wall portions. The baffle chamber and the lateral combustion
conduits have the same height. An exhaust flue for the combustion
gases is arranged at the outlet and receives the combustion gases
from the conduits.
Full details of the present invention and its advantages are set
forth in the following description of certain now preferred
embodiments thereof.
BRIEF DESCRIPTION OF DRAWING
In the accompanying drawing
FIG. 1 is a vertical section through a boiler constructed in
accordance with the present invention and showing the combustion
chamber and the fluid storage chamber mounted above, the section
being taken along line I--I of FIG. 2;
FIG. 2 is a horizontal sectional view taken along line II--II of
FIG. 1, showing in plan view the interior construction of the
boiler;
FIG. 3 is a sectional view similar to that of FIG. 2 showing a
modified embodiment of the interior boiler construction; and
FIG. 4 is a sectional view similar to FIGS. 2 and 3 showing a third
embodiment.
DETAILED DESCRIPTION
The boiler is only schematically shown in all of the figures,
omitting those well known and conventional features, such as feed
pipes, conduits, sources of fuel, valve mechanisms and other
details, which are known to those skilled in this art.
As seen in FIGS. 1 and 2, the boiler comprises a combustion chamber
1 above which a consumption water storage tank 3 is located. The
two units are enclosed in a boiler casing 2 in which a liquid
heating medium is maintained. The combustion chamber 1 is enclosed
by upper and lower plates 5 and 6 respectively and vertical water
carrying double walls 2'. This combustion chamber is further
divided by double wall bulkhead or screen 7 which is arcuately,
i.e., generally oval, shaped but spaced from the double walls 2'
and open at one end, the bulkhead defining a central baffle chamber
and a laterally surrounding combustion gas conduit 4. In the
embodiment shown in FIG. 2, an additional double wall water
carrying bulkhead 7' is provided so that a second combustion gas
conduit 4' is formed along the lateral walls 2' of the combustion
chamber. The outer double walls 2' are integrally secured to the
front wall 10' and to the rear wall 10, respectively, the front
wall defining inlet 8 and the rearwall defining an outlet 9 leading
to an exhaust flue.
The double wall bulkheads 7 and 7' extend for substantially the
entire height of the combustion chamber and define gas intake
openings 14 communicating with the baffle chamber near the inlet 8
and a terminal portion communicating with the outlet 9 in the rear
wall 10 of the boiler casing. When the additional double wall 7' is
employed, it is provided with an interruption or opening 15 which
allows the interior gas conduit 4 as well as the exterior gas
conduit 4' to communicate with the exhaust flue 9.
Apart from the exhaust flue 9, the combustion chamber 1 is
preferably provided with only the one other opening 8 extending
through the casing 2 and located at the front of the combustion
chamber. The opening 8 also extends the entire height of the casing
and is closed by a door or other suitable closure member 13 which
carries or supports a burner-blower 12, conventionally gas or oil
fed. Because the opening 8 and the door 13 extend substantially the
height of the combustion chamber 1, the entire interior of the
combustion chamber is readily accessible. Since the inlets 14 to
the gas conduits 4 and 4' are adjacent to the front end of the
combustion chamber, they, too, are readily accessible when the
closure member 13 is removed.
A liquid medium inlet KV and a liquid medium return outlet KR are
provided for supplying and reducing the quantity of liquid heat
exchange medium (preferably water) located within the casing 2 and
surrounding the combustion chamber and the storage tank 3. The
storage tank 3 is itself provided with cold water inlet WI and hot
water outlet WO. The water in the double wall bulkheads 7 and 7' is
caused to flow upwardly into the area surrounding the storage tank
3 through openings 11, formed in the upper plate 5 and lower plate
6. The openings 11 are coextensive with the cross section of the
bulkheads 7 and 7' so that the combustion chamber is made
watertight. These plates 5 and 6 may also be made slightly curved
so as to provide improved flow and pressure characteristics.
The interruption or opening 15 in the additional double wall
bulkhead 7' can also have a height substantially equivalent to the
height of the combustion chamber 1 although this is not absolutely
necessary. On the other hand, the interruption 15 may be made only
in the lower half of the bulkhead 7' so that a gas from the inner
conduit 4 may be caused to flow downwardly before reaching the
exhaust flue 9, while the gases in the outer conduit 4' will have
an upward component. This gas flow may be aided by the use of
conventional sheet metal guides or plates located in the
conduits.
The sheet metal guides or plates may be used even when the
interruption 15 extends the entire height of the combustion
chamber.
In FIGS. 3 and 4 there is once again shown a combustion chamber
defined by bulkhead 2' and having an interior baffle chamber
defined by substantially U-shaped double wall bulkhead 7,
substantially as shown in FIG. 2. The base of the bulkhead 7 is
located in front of the flue chimney 9. The burner inlet 8 is shown
although the closure member 13 and the burner 12 are omitted.
Between the side arms of the double wall bulkhead 7 and in the
interior of the combustion chamber 1 of FIG. 3 there is located an
additional pair of double wall water carrying bulkheads 16 having
front edges 17 disposed adjacent the front wall of the boiler,
leaving narrow gaps 18 which serve as gas by-passes. In FIG. 3, the
front wall of the boiler is provided with double walls 19 which are
also water bearing. In FIG. 4, the interior water carrying
bulkheads 16 are extended beyond the front edges 17 to communicate
with the forward wall portions of the front of the boiler which are
here indicated as 19'. In the embodiment of FIG. 4, the by-pass gap
18 is omitted. The direction of gas flow, as seen in FIG. 3, is
from the opening 8 substantially to the rear of the baffle chamber
(although some gas passes through by-pass 18), thence through a
first pair of conduits 4 between the interior bulkheads 16 and
bulkhead 7, following a tortuous path between the bulkheads 7 and
the exteriour bulkheads 2' until it reaches the rear wall 10 and
exits through the flue chimney 9. A similar flow path is seen in
FIG. 4, except that, in the absence of the gaps 18, there is no
by-pass of gas.
In addition to the opening 8 in the embodiment of FIGS. 3 and 4,
which opening may extend substantially the height of the boiler,
the front wall may be provided with separable or removable covers
20. The covers 20 may or may not extend the entire height of the
boiler. Shields, guides, ridges or other baffle members 21 may be
inserted, as desired, between the walls of the bulkheads 7 and 2'
and/or the bulkheads 7 or 16. These flue guide members insure the
proper flow direction and control the flow resistance within the
boiler.
In each of the embodiments shown, water is introduced by
conventional means through inlet KV passing into the bulkheads 7,
7' and 16 as well as the outer bulkheads formed by the casing wall
2 and the rear casing walls 10 and/or the front casing wall 19'.
The burner 12 is caused to heat the combustion chamber 1 of the
boiler with the gases passing through the conduits 4 and 4' about
and between the bulkheads containing the water. In each of the
embodiments shown, there are at least two water carrying walls
forming a gas flow path from the baffle chamber reversing the flow
of gas coming from the burner and then back toward the flue 9.
Preferably, there are three substantially concentric bulkheads
containing water located symmetrically about the axes of the boiler
chamber. These plural bulkheads provide a tortuous flow path for
the gases and an extremely large area for heat transference from
the heated gases to the liquid heating medium. The heated liquid is
then caused to flow upwardly into the casing about the storage tank
along the path shown by arrows A where the heat is transferred to
the water in the storage tank 3. Meanwhile, the exhausted gases
exit along the path shown by arrows B through the flue chimney
9.
The concentric location of the bulkheads as well as their proximity
to opening 8 and the door 13 (as well as to the secondary closure
doors 20) permit the interior of the boiler to be readily cleaned
from the front of it and avoid the need for the provision of
additional openings and doors into the sides or rear of the
boiler.
It will be obvious that it is possible to obtain optimem combustion
values and a good intermixing of the combustion air with the fuel
in the combustion chamber. The concentric bulkhead walls and the
tortuous flue path provide a controlled environment for producing a
predetermined and desired pressure within the boiler itself. The
flow aspects of the boiler can be correctly designed and the ratio
of combustion chamber to flue and particularly the heating surfaces
and transfer surfaces can also be predetermined to obtain the
optimum advantages.
Such boilers can be produced at low cost because the boiler walls
and the bulkhead walls can be subjected to pressure loading without
having bolts or other stiffening means. Manufacturing costs are
also reduced by making all the boiler heating surfaces accessible
through the single cleaning port, namely a closure or door 13 which
also carries the burner. In this case, the boiler requires no
openings for cleaning the flues or other heating surfaces on either
the back, top or longitudinal sides. In those rear or side areas,
the boiler also requires no openings for the removal of the
combustion residues.
According to the invention, the combustion chamber can be either
oval or circular in horizontal cross-section, so that the
combustion chamber walls can be curved and thus are capable of
being pressure loaded. The wall thickness need not be made larger
than is necessary to resist corrosion. The combustion chamber is
divided by a water carrying double wall bulkhead 7 or 16 which
forms a screen defining a baffle chamber. The outer wall of the
combustion chamber forms with the nearest water carrying bulkhead
one or several combustion gas or flue inlets which extend parallel
to the combustion chamber and surround it concentrically. Thus, the
combustion chamber heating surface is easily adapted to the
combustion gas flue size because, if in a particular model the
boiler is made high overall, the combustion chamber will also be
correspondingly high and will offer a larger heating surface. The
height of the boiler flues, transfer surfaces, etc., are all in
direct correspondence. The passages have a larger heat transfer
surface area than the inside of the combustion chamber.
If the boiler is made high the heat transfer cross-section from the
combustion chamber to the flues is automatically made larger. This
is extremely important in order to keep the flow resistance of the
combustion gases as low as possible on passing from the combustion
chamber into the flues. To insure pressure in the combustion
chamber, baffle members for guiding the gases are inserted in the
flues.
Boilers with a lower capacity can be made of circular
cross-section. The relationship between the combustion chamber and
the flues, i.e., the transfer cross-sections from the combustion
chamber to the flues, is very favorable to such construction and
ease of cleaning is ensured in the same way as with boilers having
an oval combustion chamber.
The upper and lower closure (plates 5 and 6) of the combustion
chamber and the flues can be made in two ways: firstly, continuous
plates can be provided at the top and bottom having corresponding
apertures to the bulkheads; or, secondly, one wall of the bulkheads
can be chamfered at the top and bottom and placed against the other
wall and welded at the resulting edges.
While fundamentally adhering to the constructional principle
described, the embodiments of FIGS. 3 and 4 have a further
advantage in that they provide boilers with a large thermal
capacity.
The variants shown, namely, the front edges of the addition side
walls placed just in front of the wall carrying the burner or the
additional side walls made integral with a water carrying front
wall, have other advantages.
The first variant has the particular advantage that the pressure
wave caused on starting up the boiler can largely flow away
directly laterally through the gaps between the front edges of the
side walls and the boiler front wall.
In the second variant, in horizontal cross-section three water
carrying bulkheads are mounted one within the other. Obviously, the
boiler according to FIGS. 3 and 4 and its variants offer greater
possibility for using flow guide baffle plates, vortex devices or
the arrangement of wall ridge stampings to control resistance.
It is also possible for the lateral bulkheads to be arranged so
that the gas flues decrease in cross-sections, adapting the flue
passages to the increasing reduction in volume of the gases
occuring when they cool.
* * * * *