U.S. patent number 3,800,748 [Application Number 05/322,074] was granted by the patent office on 1974-04-02 for fluid heater appliance.
This patent grant is currently assigned to M.M.S. Limited. Invention is credited to Herbert Schindler, Willard O. Ware.
United States Patent |
3,800,748 |
Schindler , et al. |
April 2, 1974 |
FLUID HEATER APPLIANCE
Abstract
A fluid heating appliance of the stackless type particularly
adapted for heating swimming pool water. A rectangular housing or
cabinet is assembled and contains a combustion chamber, a heat
exchanger capable of carrying the fluid to be heated and disposed
within said combustion chamber whereby to intercept the flow of
combustion products, a flue collector immediately adjacent said
heat exchanger, a flue products outlet chamber or duct adjacent
said flue collector and adapted to receive the combustion products
from the flue collector and having an outlet for discharge of
collected combustion products to the atmosphere, a fresh-air
intake, a control chamber communicating between said fresh-air
intake and said combustion chamber, a restricted aperture disposed
between said fresh-air intake and said control chamber for
aspirating a given quantity of air to the control chamber and at
least one passageway communicating between said fresh-air intake
and the exterior of the appliance by-passing said control chamber
whereby in adverse weather conditions, any excessive quantity of
air is directed by way of said passageway for discharge to the
atmosphere by-passing said control chamber, yet without requiring
the use of additional draft diverters, baffles, spoilers and the
like structures.
Inventors: |
Schindler; Herbert (North
Hollywood, CA), Ware; Willard O. (Stockton, CA) |
Assignee: |
M.M.S. Limited (Alameda,
CA)
|
Family
ID: |
23253299 |
Appl.
No.: |
05/322,074 |
Filed: |
January 8, 1973 |
Current U.S.
Class: |
122/367.3;
126/85B; 126/307A |
Current CPC
Class: |
F24H
1/145 (20130101) |
Current International
Class: |
F24H
1/14 (20060101); F24H 1/12 (20060101); F22b
021/00 () |
Field of
Search: |
;122/250,367R,367C,406,DIG.11 ;165/78 ;126/85B,37A |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Sprague; Kenneth W.
Assistant Examiner: Yeung; James C.
Attorney, Agent or Firm: Silverman & Cass
Claims
What we claim is:
1. A fluid heater comprising a housing, means defining air-intake
means for introducing atmospheric air into the cabinet, means
defining a combustion chamber interior of the housing, fuel burner
means within said combustion chamber, control chamber means
communicating between said air-intake means and said combustion
chamber means for feeding air thereinto, flue collector means
disposed within said housing to receive the flue products of
combustion from the combustion chamber means, heat transfer means
interposed between the flue collector means and the combustion
chamber means in intercepting relation to the path of said flue
products and capable of transferring generated heat energy from
said flue products to a fluid carried within said heat transfer
means, means defining an outlet duct communicating with said flue
collector means, said outlet duct including port means for
discharging said flue products from said outlet duct to the
exterior of the housing and means for aspirating atmospheric air
from said air-intake means to the control chamber means in
controlled quantities and including means capable of directing
quantities of air in excess of said controlled quantity from said
air-intake means to the exterior of said housing by-passing said
control chamber.
2. The fluid heater as claimed in claim 1 wherein said housing
includes front, rear and side walls, said air-intake means
comprising plural perforations formed at least in said side walls
near the upper portions thereof between said front and rear walls,
and said aspirating means comprises at least one passageway formed
interior of said housing, said plural perforations opening into
said passageway and means defining a restricted orifice interposed
between said passageway and said control chamber and said
passageway also opening to the exterior of said housing at a
location spaced from said control chamber.
3. The fluid heater as claimed in claim 2 in which said means
defining a restricted orifice comprises a wall separating said
passageway from said control chamber and an aperture defining the
sole entry to said control chamber through said wall.
4. The fluid heater as claimed in claim 3 in which said means
defining a restricted orifice includes valve means for varying the
diameter of said aperture.
5. The fluid heater as claimed in claim 2 in which said housing and
said flue collector is in heat exchange relation with said
passageway.
6. The fluid heater as claimed in claim 1 in which said housing
includes a cover defining the top wall thereof.
7. The fluid heater as claimed in claim 6 in which said cover forms
one wall of said outlet duct and port means formed in said cover
for discharging said flue products from said duct.
8. The fluid heater as claimed in claim 6 in which said port means
includes an outlet spaced from the edges of said cover and second
cover means removably secured to said cover.
9. The fluid heater as claimed in claim 1 in which said combustion
chamber is spaced from the walls of said housing to substantially
define surrounding dead-air spaces.
10. The fluid heater as claimed in claim 1 in which said housing
includes an upper covering wall and said covering wall has
perforations formed therein, said covering wall forming one wall of
said outlet duct.
11. The fluid heater as claimed in claim 7 in which said port means
includes at least two groups of perforations formed in said cover
and arranged spaced apart one group from the other.
12. The fluid heater as claimed in claim 10 in which said
perforations are arranged in at least two groups, one group spaced
from the other.
13. The fluid heater as claimed in claim 12 in which there is a
removably covered port disposed between said groups.
14. The fluid heater as claimed in claim 2 in which said plural
perforations are arranged in at least one row along the side and
rear walls.
15. The fluid heater as claimed in claim 2 in which said outlet
duct is disposed over said flue collector means and extending
across substantially the entire upper portion of the housing, said
housing including a top wall defining, with said side walls, front
and rear walls, said outlet duct.
16. The fluid heater as claimed in claim 15 in which said
passageway is defined between the housing and the flue collector
and extends along the side and rear wall of said housing, said
perforations opening to said passageway.
17. The fluid heater as claimed in claim 1 in which said port means
comprise plural perforations formed in the end walls of the duct at
the front and rear walls of the housing.
18. The fluid heater as claimed in claim 17 in which said end walls
are recessed.
19. The fluid heater as claimed in claim 16 in which said top wall
is spaced from the upper ends of said front, rear and side walls of
said housing, imperforate spacing wall means secured to the top
wall and to the upper ends of said front, rear and side walls to
define a recess, and said port means comprise perforations formed
in said spacing wall means whereby to define a clear channel
opening to the front and rear of the housing.
20. The fluid heater as claimed in claim 19 in which there is an
interior horizontal wall seated upon said flue collector means and
forming the bottom wall of said outlet duct, said horizontal wall
having a port formed therein arranged to communicate with said flue
collector means.
21. The fluid heater as claimed in claim 20 in which said interior
horizontal wall is spaced from said spacing wall means to define a
path communicating to at least one said passageway.
22. A fluid heating device comprising a housing, a combustion
chamber within the housing, burner means for combusting fuel within
said combustion chamber, heat transfer means capable of carrying
fluid and disposed in communication with said combustion chamber to
intercept the combustion products for transferring the generated
heat energy from said combustion products to the fluid, wall means
defining at least two inlet chambers within said housing,
air-intake means formed in said housing in communication with said
inlet chambers, means defining a passageway between said inlet
chambers and communicating to said combustion chamber and burner
means, flue collector means for receiving said combustion products
subsequent to passage thereof past said heat transfer means, means
defining at least one outlet chamber in communication with said
flue collector, first port means formed in said flue collector to
enable passage of combustion products thereinto and second port
means formed in said outlet chamber for discharge of said
combustion products to the exterior of said housing and air-flow
restriction means disposed within said passageway whereby a given
quantity of air from said air-intake means is introduced into said
combustion chamber and burner means and air quantities in excess of
said given quantity are directed through said housing by way of
said inlet chambers to and through said air-intake means to the
exterior of the housing.
23. The fluid heating device as claimed in claim 22 in which at
least one wall of each inlet chamber is defined by said flue
collector and another wall thereof is defined by said housing, said
last mentioned wall having a plurality of perforations formed
therein and comprising said air-intake means.
24. The fluid heating device as claimed in claim 22 wherein at
least one wall of each inlet chamber is in heat-exchange
relationship with said flue collector.
25. The fluid heating device as claimed in claim 22 in which said
wall means defining said inlet chambers and said passageway include
said flue collector, and said air-intake means comprises a
plurality of perforations substantially co-extensive with said
inlet chambers.
26. The fluid heating device as claimed in claim 22 and means
interior of said housing defining a feeding chamber forming a flow
path leading to said combustion chamber from said air-flow
restriction means.
27. The fluid heating device as claimed in claim 26 in which said
air-flow restrictor means comprise valve means.
28. The fluid heating device as claimed in claim 26 in which said
feeding chamber includes radiation shield means interposed in the
air-flow path adjacent the entrance to said combustion chamber,
said radiation shield means including leg means defining a first
path adjacent said housing and leading to said combustion chamber
and a second path between said leg means, said burner means being
arranged in said second path whereby primary air is introduced
therein for mixing with said fuel and secondary air is introduced
to said combustion chamber by way of said first and second
paths.
29. The fluid heating device as claimed in claim 28 in which baffle
means is formed in said leg means in intercepting relation relative
to said first path.
30. The fluid heater as claimed in claim 22 in which said second
port means comprises openings formed in a pair of oppositely
disposed walls of said outlet chamber to define a path in a
direction substantially normal to the axis of said first port means
and the flow of combustion products into said outlet chamber.
31. The fluid heater as claimed in claim 22 in which said second
port means comprises at least one opening formed in the wall of
said outlet chamber opposite to the first port means.
32. The fluid heater as claimed in claim 31 in which said first and
second port means are axially aligned to enable introduction of an
exterior tubular stack member therethrough.
33. The fluid heater as claimed in claim 22 in which said second
port means includes plural openings formed in said wall of said
outlet chamber.
34. The fluid heater as claimed in claim 33 in which said plural
openings are disposed in at least two groups spaced one from the
other.
Description
FIELD OF THE INVENTION
This invention relates generally to fluid heaters and more
particularly is directed to a fluid heater of the stackless type
for heating swimming pool water, said heater having air aspirating
means capable of directing sufficient air into the combustion
chamber thereof while discharging excessive air and the flue
products of combustion whereby to render the operation of the
appliance independent of varying wind velocities.
BACKGROUND OF THE INVENTION
Generally, fluid heater appliances particularly of the type which
are intended for outdoor use which are adapted for heating swimming
pool water for example, are of the gas burning type in preference
to other fuel use. Such gas burning appliances usually are provided
with a combustion chamber having a gas burner located therein. In
such devices, a quantity of gas and air under pressure is supplied
to the burner in such a manner that the air-gas mixture is ignited
by a pilot burner as it leaves the burner unit through burner
ports. Thereafter, the gas and air mixture continuously combusts
within the combustion chamber. A quantity of so-called secondary
air, that is, fresh air, also enters into the combustion chamber
from an intake opening so as to mix with the original gas-air
mixture there to complete the combustion process.
Accordingly, complete combustion of the gas is accomplished within
the combustion chamber. The so-called flue products of combustion
rise within the combustion chamber and are exhausted through a port
or outlet located above said combustion chamber. Heat transfer
devices are located below the port or outlet directly in the path
of the combustion products. Generally, the heat transfer device is
a heat exchanger including a plurality of conduits extending to
intercept the flue product flow whereby the generated heat energy
is transferred through the device to heat a fluid traveling through
the conduits. Thereafter the flue products are vented through the
port or outlet to the atmosphere. Additionally, the combustion per
se generates radiant heat also partially absorbed by the heat
exchanger and transferred to the fluid passing therethrough. The
pressure relationships within the heater are such that the hot
products of combustion rise within the combustion chamber and exit
through the outlet or port because of the difference in static
pressure that results from the reduced weight of the column of flue
products of combustion in their heated state as compared to their
state at ambient temperature. The aforesaid static pressure
differential is called "draft" and more specifically is described
as "natural draft."
Normally, gas burning appliances have been provided with various
means for equalizing the static air pressure at the outlet with the
static air pressure existing at the fresh air intake. This fresh
air is referred to in the art as so-called secondary air in
contrast to the primary air forming the air-gas combustible
mixture. Imbalance in the static air pressures adversely effects
the combustion characteristics within a reasonable range of draft.
Most known gas-burning appliances of this type normally permit
completion of the combustion within the combustion chamber.
However, excessive draft sometimes referred to as "updraft" or
"downdraft" depending upon the location of the imbalance, usually
causes either incomplete combustion, poor flame stability, flashing
of the flame or combustion outside the combustion chamber,
extinction of the flames, poor heat exchange or similar conditions
which are not only undesirable but may be hazardous and dangerous.
If the static air pressure were greater at the outlet port, a
so-called downdraft would be created which would enter the
combustion chamber through the outlet port and cause the burner
flame to deflect or mushroom sometimes passing outside the
combustion chamber. This would probably result in substantial
damage to the temperature controls, usually thermostatically
operated. Conversely, if the static air pressure were greater at
the intake, then an updraft would be created and an excessive
amount of combustion air would pass through the chamber causing the
burner to lift and carry a significant amount of the generated heat
out of the chamber without permitting or performing any useful
work. Many devices of this character locate their air intake near
the bottom of the appliance close to the gas burners and remote
from the outlet port. The distance itself makes possible a
substantial difference in static air conditions between the inlet
or intake and the outlet.
However, excessive drafts which may be created by adverse wind
conditions such as gusts, storms, act directly on the appliance or
at least act indirectly by reflection from nearby structures. Such
drafts further add to the imbalance causing draft conditions which
are detrimental to the efficient operation of the appliance. There
is a safety factor in directing a significant amount of uncombusted
products to the atmosphere by way of the outlet and of course,
often causes extinguishment of the pilot burner. This results in
down-time and erratic operation.
Heretofore, prior gas burning appliances of this type included a
stack connected to the outlet to permit the outlet to function
independently of wind velocities and static air pressure around or
near the stack. However, notwithstanding the provision of simple
stacks, downdrafts still occur. Accordingly, various means such as
draft diverters, barometric dampers, vent hoods or covers, spoilers
or the like are required to correct deficiencies described. A draft
diverter provides a relief opening through which any downdrafts
from the atmosphere are spilled or deflected into a surrounding
area rather than entering the flue ways of the appliance itself. A
barometric damper is an adjustable device of the same type and
function. A vent hood is a device that is usually located at the
terminal point of the stack to deflect the downdraft and further to
protect the interior of the appliance from precipitation.
In addition, of course, stack means that have been provided to
overcome the above mentioned deficiencies, have their own
considerable shortcomings which make their utilization undesirable.
One objection is that the stack means heretofore provided are quite
unsightly. Stacks are usually required by law or customs to extend
over the surrounding structure such as fences or eaves. If the
appliance is used as a swimming pool heater the unslightly stack
usually is clearly visible and thus reduces the esthetic appearance
of the surrounding area. Additionally, one has to recognize the
increased expense involved in the heretofore provided solutions to
the mentioned problems.
The art also indicates that one could provide a plurality of
baffles both interior and exterior the appliance to direct the
primary and secondary air and the flue products properly so as to
minimize the static pressure differential between the air intake
and the outlet, that is the exhaust port.
In addition to being generally costly, fluid heaters heretofore
necessarily equipped with draft diverters, barometric dampers, vent
covers, spoilers, baffles or similar devices required for normal
operation as an outdoor installation, were unsightly, generally
inconvenient to install, and, most often required a variation of
the designs for various different capacity appliances. Further, the
appliances were designed either for outdoor or indoor installation,
with conversion requiring substantial modifications.
Accordingly, it would be desirable to provide a fluid heater
appliance which is capable not only of outdoor installation but
also easily convertible to an indoor use without substantial
modification of the design.
It is also desirable, in an effort to reduce the cost of the fluid
heater appliance, to provide a structure which is capable of being
assembled, disassembled and reassembled conveniently, thus reducing
the cost of manufacture and also, preventing dislocation of the
various operational sections of the appliance. In addition, it is
desirable that all the advantages above mentioned be obtained
without loss in the efficiency of the appliance and in fact perhaps
with a gain in efficiency.
SUMMARY OF THE INVENTION
There is provided a fluid heater which includes a housing, means
defining air-intake means for introducing atmospheric air into the
housing, means defining a combustion chamber interior of the
housing, fuel burner means within said combustion chamber, control
chamber means communicating between said air-intake means and said
combustion chamber, flue collector means disposed to receive the
flue products of combustion from the combustion chamber, heat
transfer means interposed between said flue collector means and
said combustion chamber and capable of transferring generated heat
energy from said flue products to a fluid carried therein, means
defining an outlet duct communicating with said flue collector
means, said outlet duct having port means for discharging said flue
products from said outlet duct to the exterior of said housing and
means for aspirating atmospheric air from said air-intake means to
the control chamber means in controlled quantities, said aspirating
means, including means capable of directing quantities of air in
excess of said controlled quantity from said air-intake means to
the exterior of said housing by-passing said control chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a fluid heater constructed in
accordance with the invention;
FIG. 2 is a sectional view taken along lines 2--2 of FIG. 1 as
viewed in the direction of the arrows;
FIG. 3 is a sectional view taken along lines 3--3 of FIG. 1 as
viewed in the direction of the arrows;
FIG. 4 is a sectional view taken along lines 4--4 of FIG. 1 as
viewed in the direction of the arrows;
FIG. 5 is a perspective view of the radiation shield illustrated in
FIG. 4;
FIG. 6 is a perspective detail illustrating one of the support
channels as shown in FIG. 2;
FIG. 7 is a fragmentary sectional view taken along lines 7--7 of
FIG. 6 as viewed in the direction of the arrows;
FIG. 8 is a perspective detail illustrating one of the angle
brackets illustrated in FIG. 2;
FIG. 9 is a fragmentary perspective view of a modified embodiment
of the invention;
FIG. 10 is a fragmentary sectional view taken along lines 10--10 of
FIG. 9 as viewed in the direction of the arrows;
FIG. 11 is a fragmentary sectional view taken along lines 11--11 of
FIG. 9;
FIG. 12 is a detail view in section of the front portion of the
device illustrated in FIG. 11; and
FIG. 13 is a fragmentary detail of a channel member forming the
side wall of the outlet chamber included in the device illustrated
in FIG. 9.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, FIG. 1 illustrates a fluid heater
appliance, indicated generally by reference character 10, that is
adapted to be used as an outdoor water heater for swimming pool
water. Appliance 10 illustrated herein is a gas burning device,
although other fuels can be utilized and as well, other fluids can
be heated.
The fluid heater appliance 10 comprises an exterior housing 12
defined by front and rear walls 14 and 14', a pair of opposite side
walls 16, a base 18 and an exterior cover 20. The base 18 is formed
as a generally U-shaped channel member having depending feet 22
along the edges thereof. The walls are secured to the base 18 along
the edges of said base, each wall having flange means 24 for
securement to the feet 22 of said base 18 whereby to enclose the
interior of the appliance 10. The front wall 14 is removable to
permit access to the interior of the appliance.
A combustion chamber 26 is defined by fire walls 28 which are
supported on channels 30, 30' and 30", channels 30 and 30' being
secured to the base 18, thereby defining a rectangular enclosure
forming the combustion chamber. The channels 30 each include
horizontal flange 32 having upstanding tabs 34 formed therein, as
by cutting U-shaped slits through the flange 32 and bending the
cutout portions to an upright disposition relative to flange 32.
Flange 32 has an offset depressed edge portion 32'. L-shaped flange
36 is secured, as by spot welding along the free edge thereof to
the flange 32 so that a slot 36' is defined between it and flange
portion 32'. This provides means for sliding radiation shield 84 in
and out after assembly of the remainder of apparatus 10. Each fire
wall 28 which defines the combustion chamber 26 is seated on flange
32 between tabs 34 and flange 36. The fire walls 28 are formed of a
castible refractory material.
Heat transfer means in the form of a conventional heat exchanger 38
is located directly above the combustion chamber 26 adjacent to the
upper ends 40 of the fire walls 28. The heat exchanger 38 comprises
a bank of conduits 42 providing a continuous path for the fluid to
be heated. The ends of said conduits 42 are secured to header means
44, including inlet and outlet ports 46 and 48 respectively.
Generally the conduits are thin-walled finned tubes 50 and may
include baffle means 52 to distribute the so-called flue products
over the extent of the heat exchanger 38. The fluid to be heated is
introduced into the tubes 50 with suitable temperature measuring
means (not shown) provided to regulate the operation of the
appliance 10 in accordance with the needs for heating the
fluid.
A flue collector 54 of generally rectangular cross section
substantially is provided including a portion generally similar to
the cross section of combustion chamber 26. The flue collector 54
is positioned with its bottom edges 56 mounted to the heat
exchanger 38 and to the upper ends 40 of the fire walls 28. A pair
of angle brackets 58, each having a plurality of extensions or tabs
60 cooperating with the upper ends 16' of the exterior walls 14,
14' and 16 act to interlock the position of the flue collector 54
relative to the remaining structure. A pair of duct walls 62 and 64
each having an angle shaped cross section, further restrain the
pair of brackets 58 from dislocating, thus completely restraining
the movement of the flue collector 54 and preventing its
dislocation.
The exterior cover 20 is mountable directly to the upper ends 66 of
the exterior walls 14, 14' and 16. A plurality of gas burners 68
are positioned longitudinally spaced across the mouth 70 of the
combustion chamber 26 with each burner 68 extending completely
across the mouth 70. One end 72 of each gas burner 68 is coupled to
conventionally constructed gas supply means (not shown). The
opposite end 74 of each burner 68 is sealed and mounted to the rear
wall 85 of the radiation shield 84 by passing through L-shaped
slots 87. The end 72 is open to permit entrainment of air by the
gas received from said gas supply means, this entrained air called
"primary air".
A vertically arranged interior wall 76 bridges the front of the
housing 12 spaced rearwardly of front wall 14 and is secured, on
two sides, to the side walls 16. Wall 76 cooperates with front wall
14 and those portions of the side walls 16 to define a control
chamber 78 which houses the gas supply means, valves and other
control means (not shown), including the header means 44 containing
the temperature control means (not shown). Wall 76 prevents the
header means from becoming a part of the chamber 78. The control
compartment 78 also defines the first of a pair of air-feed
chambers to be discussed hereinafter.
The interior wall 76, at its lower end, is integral with the
channel 30" which supports the front fire wall 28. A bottom
radiation shield 84 is provided with two spaced side walls 80, 82
which join with support channels 30, 30' and cooperate with the
base 18 to form a pair of passageways 86 extending parallel to the
side walls 16. The radiation shield 84 is shown in perspective in
FIG. 5 with the passageways 86 being visible in FIG. 4.
An aperture 88 is defined at the rear portion of the walls 80, 82
of radiation shield 84 so as to permit communication of the
passageways 86 with the interior of the combustion chamber 26. Each
aperture 88 has adjacent thereto and extending into the passageway,
a guide panel 90 which aids in the turbulent free transfer of air
from said passageways 86 to the combustion chamber 26.
A plurality of somewhat regularly spaced perforations 92 are formed
in parallel rows near the upper ends 16' portion of the exterior
side walls 16 to permit communication between atmosphere and a pair
of passageways 94, 96 defined by the pair of angle brackets 58, the
flue collector 54, and the heat exchanger means 26 in cooperation
with the exterior walls 14, 16. The pair of passageways 94, 96 also
are in communication one with the other by way of front and rear
passageways 98, 100. Passageway 98 is defined across the front of
the appliance 10 by the flue collector 54 and the upper portion of
the adjacent fire walls 28, in cooperation with the front wall 14.
The rear disposed passageway 100 is defined between the rear wall
of flue collector 54 and the rear wall 14' in cooperation with one
of the fire walls 28. The passageway 98, which shall be defined in
terms of its principal function, that is of an air intake chamber,
is in communication with the interior of the combustion chamber 26
by way of restricted air-flow means in the form of aperture 102
formed in bridging wall 104 connecting the front wall 14 with the
interior wall 76 and leading to control chamber 78. The fire walls
28 are spaced a small distance from the adjacent exterior walls to
define a somewhat stagnant-air space 105 serving to heat insulate
the appliance 10. The dead air space 105 also provides an escape
path for precipitation entering the appliance.
A plurality of perforations 106, 106' are formed on the forward and
rearward regions of the exterior cover panel 20 so as to permit
communication with outlet chamber or duct 108 which is defined by
cooperation of the pair of angle brackets 58, duct walls 110 and
112, the flue collector 54 and the exterior cover panel 20. The
flue collector 54 is provided with an aperture 114 so as to permit
communication between the outlet chamber or duct 108 and the
combustion chamber by way of the spaces between the tubes or
conduits 42 of the heat exchanger 38 and said flue collector
54.
The exterior cover panel 20 is provided with a centrally located
aperture or outlet 116 which can be closed with a removably secured
cover plate 118. Any precipitation, such as rain, entering the
outlet duct 108 by way of the perforations 106, 106' formed in the
exterior cover panel 20 will be discharged from the outlet duct 108
through a plurality of drain holes (not shown) provided in the
floor 109 thereof into the dead-air spaces 104. Any rain entering
the spaces 104 from the outlet duct 108 or entering through the
perforations 35 in the side walls 16, will drop to the base 18 and
be discharged from the appliance 10 through a plurality of drain
holes located thereon (not shown).
In operation, gas under pressure is supplied to the gas burners 68,
there mixed with primary air received through aperture 102 by way
of control chamber 78 and is ignited initially by a conventional
pilot burner (not shown) as the primary air-gas mixture leaves the
burner interior through a plurality of burner ports 69 of the
burners 68. The primary air-gas mixture then combusts within the
combustion chamber 26 aided by a quantity of secondary air which is
required to complete the combustion process. The so-called
secondary air is defined as air traveling by way of aperture 102
and control chamber 78 other than the air entrained into the
burners 68 by the gas. The flue products of combustion which are
created within the confines of the combustion chamber 26 are
transferred upwards by convection through the spaces between the
conduits 42 of the heat exchanger 38 where the major portion of the
heat energy of such flue products of combustion is transferred to
the fluid moving through the conduits 42 of the heat exchanger 38.
Thus, the temperature of the flue products are reduced and the
temperature of the fluid within the confines of the heat exchanger
conduits 42 increased. The flue products of combustion then are
collected inside the flue collector 54 and transferred to the
outlet duct 108 by way of aperture 114 and are discharged from the
outlet duct 108 through perforations 106, 106' in the cover panel
20 and discharged from the appliance 10.
Under normal wind conditions, the quantity of primary and secondary
air required for complete combustion enters through the plurality
of perforations 92 into air intake chamber 98, thence is aspirated
through aperture 102 into the control compartment 78 and
transferred by way of natural draft to the interior of radiation
shield 84 and passageways 86 defined by walls 80, 82 of radiation
shield 84, thence to the burners 68 and combustion chamber 26. The
amount of air admitted into the control chamber 78 is determined by
the cross section of aperture 102. The required amount of primary
air enters the burners for mixing with the gas fuel. The required
quantity of secondary air is transferred to the combustion chamber
by way of passageways defined between the walls 80 and 82 of
radiation shield 84 and the support channels 30, and also, by
moving through the pair of passageways 86 defined between the walls
of the housing and the exterior of the radiation shields. Each of
walls 80 and 82 of radiation shield 84 is provided with a pair of
angularly outwardly extending baffles or guide panels 90 defining a
pair of apertures 88. The manner of supplying secondary air to the
combustion chamber results in the uniform supply with reduced
turbulence to the plurality of burner ports 69 thus increasing
flame stability and improving the combustion process. The guide
panels 90 function to reduce turbulence.
Under excessive wind conditions, the quantity of primary and
secondary air required for complete combustion and a quantity of
additional or excess air enters through the air-intake means
defined by the plurality of perforations 92 into the air-intake
chamber 98. The desired quantity of primary and secondary air is
transferred to the control chamber 78 by means of aperture 102 and
directed to the combustion chamber as described above. The
additional or excess quantity of air which is not required for
completing the combustion, is transferred directly from the air
intake chamber 98 to passageway 100 by way of the side passageways
94 and 96 and from there, is discharged through perforations 92 in
wall 14' to the exterior of appliance 10. If the gusts of air enter
the appliance 10 by way of perforations 92 in wall 16, the air will
travel by way of passageway 100 to side passageways 94, 96, then to
passageway 98 where the required quantity will pass through
aperture 102, the excess or remainder exiting by way of
perforations 92 of wall 16. It should be noted that perforations 92
are of rectangular configuration but, of course may take other
shapes.
It should be noted that the gas burning heater appliance 10 impedes
the excessive wind or gust causing an increased pressure at the
plurality of perforations facing the direction of the path of the
wind or gusts, and also causes a decrease in pressure at the
plurality of perforations 92 on the opposite side of the gas fired
appliance 10. A similar pressure differential will be created by
the same wind or gust at the plurality of perforations 106, 106'
formed in the exterior cover. Accordingly, any air which is caused
to enter the plurality of perforations 106 in one region of the
exterior cover, which faces the direction of the path of wind or
gust, is discharged together with the flue products of combustion
to the exterior of the housing 12 by way of the plurality of
perforations 106' formed in the other region of the cover panel
20.
It should be further noted that any wind or gusts acting on a path
downward will be impeded by the exterior cover panel and cover
plate thus preventing air from entering the combustion chamber
through the aspirating aperture 102 leading to the control chamber
78.
It should be further noted that because the inner walls of air
intake chamber 98 and of the passageways 94, 96 and 100 are formed
by the flue collector, the primary and secondary air required for
complete combustion is brought into intimate contact with the flue
collector walls and thus heat energy is transferred by conduction
through said walls from the flue products by way of the flue
collector walls to the primary and secondary air. In this way, the
temperature of the flue products is reduced and the temperature of
the primary and secondary air is increased. Accordingly, by this
means, the stack losses will be reduced and the efficiency of the
combustion process and flame stability will be improved.
It should be noted that no stack means whatsoever are required to
be connected to the outlet port 116 of the outlet duct 108 and
further, no barometric dampers, vent covers, spoilers, baffles or
the like are required. Valve means shown in broken outline, may be
provided at the aspirating aperture 102 so as to control, i.e., to
vary, the input rating to enable the appliance to be modified to
operate on a much smaller quantity of gas supply simply by varying
the size of the aspirating aperture 102.
The appliance 10 can be installed indoors simply by removing the
cover plate and inserting a conventional draft diverter (not shown)
through the outlet 116 and duct 108, mounting said draft diverter
to the discharge port 114 of the flue collector already formed of
standardized size and configuration capable of receiving such draft
diverter. The draft diverter then is connected to the conventional
outside air ducting in a conventional manner. Outlets 114 and 116
preferably are axially aligned to enable a tubular stack (not
shown) to be introduced therein if desired.
Referring now to FIG. 9, a portion of a modified embodiment of the
invention is illustrated, the modified fluid heater appliance being
designated generally by reference character 10'. Fluid heater 10'
is substantially identical to fluid heater appliance 10 but for the
outlet chamber 120 thereof. The outlet chamber 120 of appliance 10'
is defined by a pair of side walls 122 and 124 and a pair of
perforate walls 126 and 128 arranged to define the front and rear
respectively of said outlet chamber 120. The walls 122, 124, 126
and 128 are formed of U-shaped channeled members. The bottom wall
130 is seated upon the flue collector in the same manner as shown
in the description of appliance 10. A port 132 is formed in the
bottom wall 130 of the outlet chamber 120 in communication with the
interior of the flue collector.
The top wall of the outlet chamber 120 is defined by cover panel
134. Cover panel 134 carries a port 136 axially aligned with port
132. Removable cover 138 is provided to close off port 136. Except
for port 136, exterior cover 134 is imperforate, the perimetric
edges thereof being secured to said walls 122, 124, 126 and
128.
Both the front and rear walls 126 and 128 are provided with spaced
openings 140 so as to define a through path in the outlet chamber
in a straight line from the front to the rear of the appliance 10'.
The channel members defining the outlet chamber walls, that is the
side walls 122, 124 and front and rear walls 126, 128, comprise
U-shaped sections 141 having top and bottom flanges 144 and 146,
with the bottom flanges 146 only of walls 122 and 124 having
depending tabs 148 formed by slitting said flange 146 in spaced
locations along its length and bending the resulting slit portions
at an angle relative to the flange 146. The tabs 148 so defined
interlock with edge flange 129 of floor 130 of the outlet chamber
with the remaining flange 146 fixedly secured to flanges 152
provided at the upper ends of the exterior walls of the housing
12'.
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