U.S. patent number 3,601,118 [Application Number 04/867,439] was granted by the patent office on 1971-08-24 for downdraft safety device for combustion gas flues.
This patent grant is currently assigned to Joh. Vaillant KG. Invention is credited to George Hein, Erich Tropp.
United States Patent |
3,601,118 |
Hein , et al. |
August 24, 1971 |
DOWNDRAFT SAFETY DEVICE FOR COMBUSTION GAS FLUES
Abstract
This invention relates to an improvement in a downdraft safety
device, e.g., for a gas-heated liquid heater. The device is
arranged inside of a cowling provided with lateral outlets, and
includes a lower flue gas collecting hood defined in front and in
the rear by the front and back panels of the downdraft safety
device, and a baffle arranged above the glue gas collecting hood in
the vicinity of the outlet connected between front and back panels.
The hood defining, inwardly inclined portions of the front and back
panels, each provide an opening at their tops for venting the
device through the respective front and back panels.
Inventors: |
Hein; George (N/A), Tropp;
Erich (N/A, DT) |
Assignee: |
KG; Joh. Vaillant
(N/A)
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Family
ID: |
5715061 |
Appl.
No.: |
04/867,439 |
Filed: |
October 20, 1969 |
Foreign Application Priority Data
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Dec 3, 1968 [DT] |
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P 18 12 361.0 |
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Current U.S.
Class: |
126/307A |
Current CPC
Class: |
F24H
9/205 (20130101); F24H 9/2042 (20130101) |
Current International
Class: |
F24H
9/20 (20060101); f23j 011/00 () |
Field of
Search: |
;125/307,37A |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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531,032 |
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Aug 1931 |
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DD |
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634,044 |
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Aug 1936 |
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DD |
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998,554 |
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Jul 1965 |
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GB |
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Primary Examiner: Myhre; Charles J.
Claims
We claim:
1. In a gas-heated liquid heater downdraft safety device, which
device is arranged inside a cowling having lateral cowling outlets,
which device includes lateral outlets aligned with said lateral
cowling outlets and side panels inwardly of said outlets of the
device, which device includes a lower flue gas inlet defined in
front and rear by front and back panels, respectively, and said
side panels of the downdraft safety device, which device includes a
baffle arranged between the flue gas inlet and a flue gas outlet,
the baffle being positioned at a level above the tops of the
lateral outlets, and at a level substantially below the flue gas
outlet from the safety device, the improvement in which:
front and back portions of the flue gas inlet are defined by
upwardly and inwardly inclined panels connected at the bottom
thereof to the respective front or back panel, said inclined panels
forming an inner wall of a conduit connecting the interior of the
safety device to the exterior of the safety device.
2. In a downdraft safety device adapted for use in a conduit
connecting a combustion chamber to a stack, which device includes a
front and back panel, a flue gas inlet at the bottom thereof, a
flue gas outlet at the top thereof, baffle means positioned between
said inlet and said outlet for preventing direct flow between said
inlet and said outlet, said device including relatively large,
laterally positioned vents, the top of said vents being at a level
below said baffle means, said baffle means permitting flow around
all sides thereof, the improvement in which:
the inlet comprises an upwardly and inwardly narrowing hood having
a front, back and sidewalls, said front and backwall being stamped
from said front and back panel, respectively, each of said front
and backwalls providing an opening between the top thereof and the
adjacent front or back panel of the device, each of said openings
providing communication between the interior and the exterior of
the device.
Description
BACKGROUND OF THE INVENTION
It is well known that a downdraft safety device of the type
indicated is intended, if downdraft occurs, i.e., if wind enters
into the flue stack from above, to direct the downdraft, together
with uprising flue gases, to lateral outlets of the cowling, and to
prevent the downdraft from passing into the combustion chamber. For
this purpose, a baffle is provided by which the downdraft is
deflected towards lower-lying lateral outlets. If no downdraft is
present, the baffle is circumcirculated by the uprising flue
gases.
Prior art downdraft safety devices of the type indicated, such as
in accordance with the German Pat. Application P 16 79 775.4,
fulfil their function for a specific rated output of the apparatus.
With the prior constructions, an overload is possible only to a
limited extent without endangering the specified burning safety. It
is an object of this invention to provide an apparatus of higher
output in which the above described principle of the draft diverter
is utilized and, for reasons of economy, the same fins are used in
the apparatus having a higher output. By way of example, the rated
output of a type of apparatus of previously 79,400 BTU/h can be
increased to approximately 95,280 BTU/h. The fin block is increased
by the addition of fins. The diameter of the flue pipe being
maintained, the flue gas system for the greater flue gas volume in
all three states, namely, updraft, obstructed flow, and downdraft,
must satisfy the known specifications. By increasing the number of
fins, it has already been determined that the apparatus shall be
changed only with respect to its width. Therefore, first the flue
gas collecting hood following the fin body, of the draft diverter
is enlarged. This enlargement renders the lateral exhaust of the
flue gas volume more difficult, particularly in the presence of
downdraft.
For feeding the greater flue gas volume, a greater height of
updraft is required in the apparatus, when the diameter of the flue
pipe is maintained, in order to achieve a stronger updraft of the
flue gases. To increase this updraft, the height of the upper draft
portion-measured from the upper edge of the lateral openings of the
draft diverter to the flue pipe-is increased. At the same time,
these upper edges are shifted outwardly in keeping with the
enlargement of the fin block. Thereby, the great amount of flue gas
is trapped in a wider upper portion of the draft diverter and is
exhausted by the greater updraft through the flue pipe of same
diameter as with an apparatus of less output. The height of the two
lateral openings of the draft diverter enters only irrelevantly
into this reflection.
To control downdraft from the stack, a baffle plate is used which
is known per se. In the enlarged apparatus, this baffle plate is
acting to deflect the downdraft towards all sides. The laterally
deflected portion of the downdraft volume escapes through the upper
portion of the two lateral openings of the downdraft safety device.
One portion of the partial downdraft deflected forwardly and
backwardly by the baffle plate is divided at the closed front and
back panels of the downdraft safety device and joins the two
laterally directed flows. The central portion of this downdraft
deflected forwardly and backwardly by the baffle plate cannot join
the lateral partial flows and evades downwardly.
It is an object of the present invention to provide a downdraft
safety device of the type indicated in the beginning, in which the
central portion of the downdraft deflected forwardly and backwardly
by the baffle plate cannot act in opposition to the uprising flue
gas flow from the fin body and impair the combustion.
It is another object of the present invention, with a downdraft
safety device of the type indicated in the beginning to render
possible an increase of the rated output of the apparatus by the
measures hereinbefore described, without impairing the burning
safety.
SUMMARY OF THE INVENTION
According to the invention these objects are attained by providing
one blade-type stamped element open at the top and projecting
inwardly in that portion of both the front and back panels,
respectively, defining the lower flue gas collecting hood. By these
stamped elements, the two residual flows are discharged forwardly
and backwardly out of the draft diverter.
DESIGNATION OF THE FIGURES
An illustrative draft diverter in accordance with the present
invention will now be described with reference to the accompanying
drawing in which:
FIG. 1 is a schematic front elevational view of the downdraft
safety device positioned within a cowling.
FIG. 2 is a side elevational view of the safety device without the
cowling.
DESCRIPTION OF PREFERRED EMBODIMENT
Fin body 1 of a heat exchanger 2 of a gas-heated instantaneous flow
heater is followed, at the top, by a downdraft safety device
generally referenced 3. Such downdraft safety devices serve the
function of ensuring the safe burning of the gas burner (not
illustrated) disposed below the heat exchanger 2, under updraft,
obstructed flow, and downdraft, in the stack.
The downdraft safety device comprises a flue gas collecting hood 4.
This collecting hood is formed by the flat front and back panels 5
and 6 of the downdraft safety device (FIG. 2) as well as by two
guide plates 7 and 8 facing each other, inclined over the fin
block. After the hot fuel gas has transmitted its heat to the heat
exchanger 2, it enters the collecting hood 4. Under updraft, the
flue gas then circumcirculates a baffle plate 9 disposed above the
collecting hood 4, in order to reunite behind the same. Then, it is
exhausted into a stack (not shown) through a flue gas conduit 10
terminating a spaced distance above the baffle plate 9.
When flow in the stack is obstructed, the flue gases discharge into
the installation space of the apparatus on both sides through
openings 11 and 12 of the downdraft safety device as well as
through openings 13 and 14 of cowling 15. Openings 11 and 12 are
defined, laterally, by the spaced-apart flat panels 5 and 6 of the
downdraft safety device. Openings 11 and 12 are defined below, by a
lower end plate 16 closing off the space between the heating body 2
and the cowling 15 and surrounding the fin body 1; openings 11, 12
are defined, at the top, by two panels 17 and 18 inclined towards
each other and joining the mouth of flue conduit 10.
Gases flowing downwardly from the flue conduit 10 under downdraft
impinge upon the baffle plate 9 from which they are deflected
towards all sides. At the same time, the flue gases directed
upwardly from flue gas collecting hood 4, from below, impinge upon
the underside of the baffle plate 9 and are also deflected towards
all sides. By the deflection two main flows are created discharging
through openings 11, 13, and 12, 14, respectively.
A portion of the rising flue gas as well as a portion of the
downdraft gas impinge upon each other centrally in front of, and
behind, baffle plate 9, and are not carried along by the two main
flows created. For this reason, one cavitylike, stamped element 19,
20, respectively, is provided in flat front panel 5 and in back
panel 6, respectively, each element 19, 20 providing upwardly
directed openings 19' and 20', respectively. Openings 19', 20' are
about as long as the opening of flue gas collecting hood 4. When
stack flow is obstructed, or under downdraft conditions, the
previously mentioned central portion of the flue gas flow in front
of, and behind, baffle plate 9 are discharged through openings,
19', 20'.
* * * * *