Note: Descriptions are shown in the official language in which they were submitted.
CA 02611161 2007-12-05
WO 2006/135145 PCT/KR2006/000580
Description
DISCRETE DOUBLE HEAT EXCHANGE TYPE HOT WATER
BOILER
Technical Field
[1] The present invention relates, in general, to hot water boilers and, more
particularly,
to a discrete double heat exchange type hot water boiler in which a water
chamber,
which is provided around a sidewall of a firebox and is nonresistant to the
high
pressure of service water, is not affected by the pressure of service water,
thus
preventing a lower part of a main body of the boiler from being damaged by the
high
pressure of service water, and in which an exhaust hood, a heat exchange unit
and the
firebox are manufactured apart so as to be separable from each other, so that
their
packing and carrying processes are easy, and they can be easily assembled
together on
site.
Background Art
[2] Boilers are devices which generate heat water by exchanging heat between
water
and hot burners. Generally, according to the intended purpose, such boilers
are
classified into heating boilers, hot water boilers and heating and hot water-
combined
boilers.
[3] The hot water boilers are mainly used in places where a large amount of
hot water
is used, for example, public bathhouses, saunas, factories, etc. FIG. 1 is a
sectional
view showing a conventional hot water boiler. As shown in Fig. 1, in the
conventional
hot water boiler, a main body 1 is formed in a single body, and a water
chamber 2, into
which fire tubes 6 are inserted, is defined in the main body 1. Furthermore, a
firebox 5
is provided at a lower position in the main body 1, and an exhaust hood 9 is
provided
on the upper end of the main body 1.
[4] An inlet 3 and an outlet 4, which communicate with the water chamber 2
that is
provided in the main body 1 to contain water therein, are formed in the main
body 1
such that running water is drawn through the inlet 3 and is discharged through
the
outlet 4 after being processed through a heat exchange process. The fire tubes
6 are
vertically provided through the water chamber 2, so that combustion gas of a
burner 10
transfers heat to water, which is in the water chamber 2 surrounding the fire
tubes 6,
while passing through the fire tubes 6.
[5] In the conventional hot water boiler having the above-mentioned
construction, the
water chamber 2, having the fire tubes therein, extends to the lower end of
the main
body 1 and surrounds the firebox 5, which is provided at the lower position in
the main
body 1. The surface 7 of the water chamber at the junction with the firebox 5
has a
2
WO 2006/135145 PCT/KR2006/000580
corrugated shape. Furthermore, a lower support plate 8 made of a refractory
material is
coupled to the lower end of the water chamber.
[6] The burner 10 is mounted at a predetermined position through the lower
part of the
main body 2. Combustion gas of the burner 10 flows through the firebox 5 to
the fire
tubes 6, then is exhausted outside through a gas duct after getting together
in the
exhaust hood 9 provided on the upper end of the main body.
[7] The conventional hot water boiler having the above-mentioned construction
has the
following differences from a heating boiler with respect to manufacturing
process.
[8] The heating boiler uses water, which is heated by combustion gas, as
heating water.
The term heating water means heated water that circulates in a pipeline to
heat a room.
On the other hand, the hot water boiler uses water that is heated by
combustion gas, as
hot water. The term hot water means heated water, which is discharged through
for
example a water tap so as to be used in a bath or the like.
[9] Therefore, heating water of the heating boiler is not necessary to be
clean, but the
cleanliness of hot water of the hot water boiler must be maintained so that it
can be
used in a bath or the like. For this reason, the main body of the conventional
heating
boiler can be made of iron material which is inexpensive and has superior
strength.
However, in the case of the hot water boiler, if the main body thereof is made
of iron
material, because there is the likelihood of the occurrence of rust, the main
body of the
conventional hot water boiler must be made of metal, such as copper or
stainless steel,
or must be manufactured by using zinc-galvanized iron material.
[10] Furthermore, in the case that a hot water coil, which is connected to a
running water
pipe, is provided in the heating boiler so as to make it possible to use hot
water, the hot
water coil is made of copper, differently from the material of the main body
of the
heating boiler.
[11] Meanwhile, the main body of the conventional hot water boiler is formed
in an
single structure. The water chamber, which contains therein water for the
supply of hot
water, extends to the lower end of the sidewall of the firebox. The water
chamber is
constructed such that it sustains the pressure of service water, the pressure
of a water
tank which is placed on the top of a house or the pressure of a water supply
pump, as
well as expansion pressure of its own water when hot water is generated.
However, the
part of the water chamber disposed around the firebox in the lower part of the
main
body and the part of the water chamber around the burner seating hole, to
which heat
from the burner is directly applied, are directly affected both by flames of
the burner
and by the pressure of running water to be supplied. Accordingly, these parts
are
structurally fragile, so that they can not bear up against expansion pressure
of heated
water and pressure of exterior water service, thus be easily ruptured by
excessive high
pressure of running water and the pressure difference between their inside and
outside.
CA 02611161 2007-12-05
3
WO 2006/135145 PCT/KR2006/000580
[12] To prevent these problems, regulators or safety pins have been used.
However, the
regulator has a disadvantageous effect on mass water supply, in which a large
amount
of hot water is discharged in a short time. The safety pin wastes energy by
draining hot
water when the hot water boiler is not in service to control pressure in the
boiler.
[13] Furthermore, a large amount of material is required to ensure sufficient
thickness of
the sidewall of the main body of the boiler, and the surface of the water
chamber which
is around the sidewall of the firebox is corrugated to form a pressure-
resistant
structure. Therefore, the conventional hot water boiler has disadvantages in
that the
workability is reduced and the manufacturing cost thereof is increased.
[14] As well, unlike the heating boilers for home use, almost all of mass
storage-hot
water boilers, which have capacities from 50,000 kcal to 500,000 kcal and are
used in
public bathhouses, saunas and factories that require a large amount of hot
water, are
installed in basements of buildings. Accordingly, in the case of the
conventional hot
water boiler having an single structure, it is difficult to carry it to a
basement, so that it
may be required to hire a professional company for transport and installation.
Disclosure of Invention
Technical Problem
[15] The present invention has been made to solve the above problems occurring
in the
prior art. An object of the present invention is to provide a discrete double
heat
exchange type hot water boiler, in which an exhaust hood, a heat exchange unit
and a
firebox constituting a main body are manufactured apart so as to be separable
from
each other, so that their packing and carrying processes are easy, and so that
they can
be easily assembled together on site, and in which a water chamber defined in
the
firebox is not damaged by water pressure.
Technical Solution
[16] In order to accomplish the above object, the present invention provides a
discrete
double heat exchange type hot water boiler comprising a heat exchange unit
having a
hot water chamber defined in a cylindrical outer casing and containing hot
water
therein, a plurality of fire tubes formed through the hot water chamber, and
an inlet and
an outlet formed through the outer casing to communicate the hot water chamber
with
an outside; a firebox coupled to a lower end of the heat exchange unit and
having a
heat exchange water chamber defined in a cylindrical outer casing, with a
burner
mounted to the firebox through a burner seating hole formed at a predetermined
position through a sidewall of the firebox; an exhaust hood coupled to an
upper end of
the heat exchange unit and having a gas duct through which combustion gas from
the
fire tubes is exhausted outside; and a heat exchange coil installed in the hot
water
chamber of the heat exchange unit, the heat exchange coil having an inlet end
and an
CA 02611161 2007-12-05
4
WO 2006/135145 PCT/KR2006/000580
outlet end respectively connected to the outlet and the inlet of the heat
exchange water
chamber of the firebox through a circulation pipe, whereby when heat exchange
water
circulates in the heat exchange coil, heat is transferred between heat
exchange water
and the hot water in the hot water chamber,.
[17] Preferably, the exhaust hood, the heat exchange unit and the firebox may
be man-
ufactured separately to be transportable, and are assembled together using
brackets.
The discrete double heat exchange type hot water boiler may further comprise a
circulation pump provided on the circulation pipe, which connects the heat
exchange
water chamber of the firebox with the heat exchange coil, whereby forcibly
circulating
the heat exchange water; and an expansion tank connected to the heat exchange
water
chamber through a running water pipe.
[18] Preferably, a plurality of heat exchange coils may be installed in the
hot water
chamber of the heat exchange unit, inlet ends and outlet ends of the heat
exchange
coils being respectively connected to outlets and inlets formed in the heat
exchange
water chamber through circulation pipes and circulation pumps are respectively
provided on the circulation pipes, so that the heat exchange water transfers
heat from
the heat exchange water chamber to the hot water chamber while forming a
plurality of
flow streams.
Advantageous Effects
[19] In the hot water boiler according to the present invention, an exhaust
hood, a heat
exchange unit and a firebox constituting a main body are manufactured apart so
as to
be separable from each other. Particularly, because the heat exchange unit and
the
firebox with relatively large sizes are separably provided, their packing and
carrying
processes become easy, thus making it easy to carry them in a basement, in
which the
hot water boiler is mainly installed. Furthermore, the elements of the hot
water boiler
can be easily assembled together on site. As such, the present invention has
advantages
of ease of transport and installation. As well, when repair is required, it is
possible to
separate only the related element from the main body to repair or replace it
with a new
one. Therefore, after-sales service is simplified.
[20] Furthermore, according to the present invention, because the firebox is
not in
contact with hot water, it is possible to manufacture the firebox from iron
material,
which is inexpensive and has superior strength but has been limitedly used due
to the
probability of occurrence of rust. The iron material has a superior pressure-
proof
feature and superior workability, for example, superior welding process.
Therefore, the
present invention reduces manufacturing costs and simplifies the structure
thereof. In
addition, the present invention is constructed such that the water chamber of
the
firebox is not dependent on the pressure of service water. Accordingly, unlike
the con-
CA 02611161 2007-12-05
5
WO 2006/135145 PCT/KR2006/000580
ventional art where the lower part of the boiler is structurally fragile, the
present
invention has a structure such that the lower part of the main body of the
boiler is not
affected by the pressure of service water, thus preventing the lower part of
the main
body from being damaged. Furthermore, because the firebox does not require
high
pressure resistance and the probability of damage to the firebox is low,
processes of
machining and manufacturing the boiler are simplified. Moreover, the present
invention has an advantage in that the stability of the main body of the
boiler is
ensured even without a safety pin or a regulator.
[21] In addition, according to the present invention, hot water is heated by
both
combustion gas flowing in fire tubes and heat exchange water rapidly heated at
a
position adjacent to the flames. Therefore, the hot water can be rapidly
heated as well
as can be maintained in a clean state, so that the heat exchange efficiency
and the
performance of the boiler are markedly enhanced.
Brief Description of the Drawings
[22] Fig. 1 is a sectional view showing a conventional hot water boiler;
[23] FIG. 2 is an exploded sectional view showing a main body of a discrete
double heat
exchange type hot water boiler according to a first embodiment of the present
invention;
[24] Fig. 3 is a view showing the construction of the assembled discrete
double heat
exchange type hot water boiler according to the present invention;
[25] Fig. 4 is a sectional view showing a firebox of a discrete double heat
exchange type
hot water boiler according to a second embodiment of the present invention;
and
[26] Fig. 5 is a view showing the assembled discrete double heat exchange type
hot
water boiler according to the second embodiment of the present invention.
Best Mode for Carrying Out the Invention
[27] Hereinafter, preferred embodiments of the present invention will be
described in
detail with reference to the attached drawings.
[28] Fig. 2 is an exploded sectional view showing a main body of a discrete
double heat
exchange type hot water boiler according to a first embodiment of the present
invention. Fig. 3 is a view showing the construction of the assembled discrete
double
heat exchange type hot water boiler of the present invention.
[29] As shown in Fig. 2 and Fig. 3, the first embodiment of the present
invention
comprises an exhaust hood 20, a heat exchange unit 30 and a firebox 50 which
are
manufactured apart so as to be assembled together. The first embodiment
further
comprises a heat exchange coi160 provided in the heat exchange unit 30.
[30] The heat exchange unit 30 includes a hot water chamber 35 which is an
upper water
chamber that is defined by a cylindrical outer casing 32 and by upper and
lower plates
CA 02611161 2007-12-05
6
WO 2006/135145 PCT/KR2006/000580
34, 36 respectively coupled to the upper and lower ends of the outer casing.
The heat
exchange unit 30 further includes a plurality of fire tubes 38 vertically
arranged
through the hot water chamber 35, and combustion gas flows in the fire tubes
38. Heat
is transferred between combustion gas flowing in the fire tubes 38, and water,
that is,
hot water, which is in the hot water chamber 35 and surrounds the fire tubes
38.
[31] Furthermore, the heat exchange unit 30 includes an inlet 42 and an outlet
44 which
are formed at predetermined positions through the outer casing 32 and
communicate
with the hot water chamber 35. The inlet 42 is connected to a water supply
pipe and
serves as a passage which receives water to be used for hot water. The outlet
44 serves
as a passage which discharges water, which has been heated in the hot water
chamber
35, towards a water tap of a bathroom or the like.
[32] Meanwhile, the heat exchange coi160, which is wound in a spiral shape, is
installed
in the hot water chamber 35 of the heat exchange unit 30. An inlet end 62 and
an outlet
end 64 of the heat exchange coi160 extend outside through the outer casing 32
of the
heat exchange unit 30 and are connected to circulation pipes 65.
[33] The firebox 50 is manufactured separately from the heat exchange unit 30,
and is
attached to the lower end of the heat exchange unit 30. The firebox 50
includes a heat
exchange water chamber 55, which is a lower water chamber defined in a
cylindrical
outer casing 52 and is formed separately from the hot water chamber 35 of the
heat
exchange unit 30. Heat exchange water is not discharged outside, unlike hot
water, but
is used as a heat exchange medium, which circulates to realize heat exchange.
The heat
exchange water chamber 55 has an outlet 58, which is formed through a sidewall
at a
position adjacent to a burner seating hole 11, and an inlet 57, which is
formed through
the sidewall at a position opposite the burner seating hole 11 and adjacent to
an upper
end plate 56. The outlet 58 and the inlet 57 are respectively connected to the
inlet end
62 of the heat exchange coi160 and to the outlet end 64 through the
circulation pipes
65, such that heat exchange water circulates in the heat exchange coi160
provided in
the hot water chamber 35 of the heat exchange unit 30. The burner seating hole
11 is
formed at a predetermined position through the sidewall of the heat exchange
water
chamber 55.
[34] Furthermore, a circulation pump 70 is provided on one of the circulation
pipes 65,
which connects the heat exchange water chamber 55 to the heat exchange coi160
to
circulate heat exchange water. Preferably, the circulation pump 70 is provided
on the
circulation pipe 65, which is disposed between the outlet 58 of the heat
exchange
chamber 55 and the inlet end 62 of the heat exchange coi160, so that heat
exchange
water, which is discharged through the outlet of the heat exchange water
chamber 55
by pumping pressure of the circulation pump 70, is pumped into the heat
exchange coil
60, thus the heat exchange water forcibly circulates between the heat exchange
water
CA 02611161 2007-12-05
7
WO 2006/135145 PCT/KR2006/000580
chamber 55 and the heat exchange coi160.
[35] The heat exchange water chamber 55 is connected to an expansion tank 80.
The
heat exchange water chamber 55 and the heat exchange coi160 define a heat
exchange
water circulation path. Here, because the heat exchange water chamber 55 is
connected
to the expansion tank 80, the heat exchange water, which circulates in the
heat
exchange water chamber 55 and the heat exchange coi160, is maintained at at-
mospheric pressure, thus preventing the boiler from being affected by
expansion
pressure generated when heating water. Furthermore, the expansion tank 80 is
connected to the water supply pipe and is constructed such that water is
automatically
supplied into the expansion tank 80 using a float valve 82. Thus, even if some
heat
exchange water is lost through, for example, evaporation, in a circulation
process, an
amount of water corresponding to the lost amount is automatically
supplemented.
Furthermore, the expansion tank 80 may be coupled to an extension line of the
circulation pipe 65 through a branch pipe. In this case, because the
circulation pipe 65
is connected to the heat exchange water chamber 55, it is substantially equal
to the case
in which the expansion tank 80 is directly connected to the heat exchange
water
chamber 55 through a branch pipe, in that the heat exchange water is open to
the
atmosphere.
[36] Meanwhile, the heat exchange unit 30 is installed on the upper surface of
the upper
end plate 56, which has a U-shaped cross-section and is bolted to the upper
end of the
heat exchange water chamber 55 of the firebox 50 using brackets 31 and 51. In
other
words, the upper end plate 56 serves as a support for the heat exchange unit
30.
[37] A burner 10 is mounted to the firebox 50 through the burner seating hole
11 formed
through the sidewall of the firebox 50. Combustion heat of the burner 10 heats
the heat
exchange water chamber 55 defined at the side of the firebox 50 and heats the
hot
water chamber 35 while moving along the fire tubes 38 of the heat exchange
unit 30.
Furthermore, an overheat detecting sensor 59 is installed in the heat exchange
water
chamber 55 so that, when the heat exchange water chamber 55 is overheated, the
operation of the burner 10 is automatically stopped.
[38] The exhaust hood 20 is placed on the upper end of the heat exchange unit
30 and is
bolted together using brackets 21 and 31. In the exhaust hood 20, combustion
gas,
which has passed through the fire tubes 38, is exhausted outside through a gas
duct 25.
[39] Fig. 4 and Fig. 5 illustrate a discrete double heat exchange type hot
water boiler
having a plurality of heat exchange coils according to a second embodiment of
the
present invention. Fig. 4 is a sectional view of a firebox of the hot water
boiler. Fig. 5
is a view showing the assembled hot water boiler.
[40] Referring to the drawings, Fig. 4 shows one set of two pairs of pipe
holes, that is,
two outlets 58a, 58b and two inlets 57a, 57b which are provided in a heat
exchange
CA 02611161 2007-12-05
8
WO 2006/135145 PCT/KR2006/000580
chamber 55 of the firebox. The two outlets 58a, 58b are provided in a sidewall
of the
firebox at positions adjacent to a burner seating hole 11. The two inlets 57a,
57b are
provided in the sidewall of the firebox at positions opposite the burner
seating hole 11.
Fig. 5 shows the two heat exchange coils 60a, 60b installed in a hot water
chamber 35
of a heat exchange unit 30.
[41] In the hot water boiler, as the capacity thereof is increased, the size
of the main
body of the boiler is increased. The increase in size of the boiler results in
an increase
of the amount of hot water contained in the hot water chamber 35. Thereby, the
capacity of hot water supply is increased, and, in addition, the capacity of
the heat
exchange chamber 55 is increased so that the amount of heat exchange water is
increased. Of course, an increase in the capacity of a burner 10 results in
increased
combustion heat. Due to the increase of combustion heat of the burner 10, an
increase
in the flow rate of heat exchange water is required to prevent the firebox 50
from
overheating, and to reduce heat loss. In this case, a method of increasing the
flow rate
of heat exchange water by increasing both the capacity of a circulation pump
and the
diameter of the heat exchange coi160 may be considered. However, it is more
efficient
to install a plurality of exchange coils 60a, 60b in the hot water chamber 35
of the heat
exchange unit 30 such that heat exchange water circulates in the plurality of
exchange
coils 60a, 60b.
[42] In detail, the first heat exchange coi160a and the second heat exchange
coi160b are
separately disposed at upper and lower positions in the hot water chamber 35
of the
heat exchange unit 30. Their inlet ends 62a, 62b and outlet ends 64a, 64b are
re-
spectively connected to the outlets 58a, 58b and the inlets 57a, 57b, which
are provided
in the heat exchange water chamber 55, through circulation pipes 65a, 65b.
Furthermore, circulation pumps 70a, 70b are respectively provided on the
circulation
pipes 65a, 65b, which respectively connect the outlets 58a, 58b of the heat
exchange
water chamber 55 with the inlet ends 62a, 62b of the heat exchange coils 60a,
60b.
[43] The operation and effect of the discrete double heat exchange type hot
water boiler
of the present invention with the above-mentioned construction will be
explained with
reference to Fig. 2 and Fig. 3.
[44] In the present invention, the exhaust hood 20, the heat exchange unit 30
and the
firebox 30 are manufactured separately and bolted together using the brackets
21, 31
and 51. Particularly, the heat exchange chamber 55, which is provided on the
sidewall
of the firebox 50, does not contain hot water to be used for bathing or the
like.
Therefore, while the heat exchange unit 30 and the heat exchange coi160, which
must
maintain superior cleanliness, should be made of copper or stainless steel
without
possibility of rust, as in the conventional art, the firebox 50 may be made of
iron
material, which is relatively inexpensive and ensures sufficient strength.
Furthermore,
CA 02611161 2007-12-05
9
WO 2006/135145 PCT/KR2006/000580
because the heat exchange water chamber 55 of the firebox 50 is not dependent
on the
pressure of service water supply, it is not required to form an inner casing
54 of the
heat exchange water chamber 55 in a corrugated shape to deal with excessive
water
pressure. Therefore, it is possible to make the inner casing relatively thin,
so it is easy
to machine and manufacture it.
[45] In addition, in the present invention, the heat exchange unit 30 is
mounted onto the
upper surface of the upper end plate 56 of the firebox 50. Therefore, the
firebox 50
serves as a support for the heat exchange unit 50, thus making it easy to
conduct the
assembly work. After the heat exchange unit 30 is placed on the upper end
plate 56 of
the firebox 50, the junction therebetween is sealed, and the brackets 31 and
51, which
are respectively attached to the sidewall of the heat exchange unit 30 and the
firebox
50, are fastened to each other by bolting, thus completing the assembly
process.
[46] Fuel supplied from a fuel supply device (not shown) is injected into the
firebox 50
through the burner 10 and is ignited to generate combustion heat. Combustion
gas first
heats the heat exchange water chamber 55 of the firebox 50 to warm the heat
exchange
water. Because the heat exchange water chamber 55 has a volume smaller than
the hot
water chamber 35 and is disposed at a position that is directly affected by
the flames,
the heat exchange water chamber 55 is heated relatively rapidly.
[47] Thereafter, the combustion gas flows upwards and heats the fire tubes 38
while
passing through the fire tubes 38, so that hot water in the hot water chamber
35
surrounding the fire tubes 38 is heated.
[48] At this time, the heat exchange water heated in the firebox 50 is
circulated in the
heat exchange coils 60, which are in the heat exchange water chamber 35 of the
heat
exchange unit 30, by the circulation pump 70. As a result, the hot water in
the hot
water chamber 35 of the heat exchange unit 30 is heated by double heat
exchange both
with the combustion gas which flows in the fire tubes 38, and with the heat
exchange
water which flows through the heat exchange coi160.
[49] Meanwhile, the heat exchange water maintains the state of being open to
the
atmosphere through the expansion tank 80, and water is automatically
supplemented
by the expansion tank 80, thus preventing the heat exchange water chamber 55
from
being damaged by the expansion pressure of water. Furthermore, even if some
heat
exchange water is lost by some causes, for example, by cold evaporation, an
amount of
water corresponding to the shortage is automatically supplemented.
[50] As well, to prepare for when the boiler is overheated by the accumulation
of
combustion heat by the burner 10, the overheat detecting sensor 59 is provided
in the
heat exchange water chamber 55, so that, when the boiler is overheated, the
operation
of the burner 10 is automatically stopped, thus increasing the safety thereof.
That is,
when the overheat detecting sensor 59 detects an overheat condition, the
operation of
CA 02611161 2007-12-05
10
WO 2006/135145 PCT/KR2006/000580
the burner 10 is stopped while heat exchange water is circulated by the
circulation
pump 70 and transfers heat from the firebox 50 to the heat exchange unit 30.
Meanwhile, the circulation pump 70 is controlled such that it is operated only
when the
temperature of heat exchange water is increased above a preset temperature.
CA 02611161 2007-12-05
