[0001] The present invention relates to an improved gas fireplace, particularly suitable
for heating house spaces.
[0002] Numerous fireplaces have been proposed in the art that are fed with gas, generally
methane gas or, more recently, gpl (liquefied petroleum gas).
[0003] Conventional gas fireplaces generally comprise either a frontally closed combustion
chamber or a frontally open fireside, a comburent air intake, an exhaust duct for
flue gases, and an air circuit designed to suck room air to be heated, to heat the
sucked air, and to discharge the heated air into the room where the gas fireplace
is located.
[0004] Such fireplaces have a number of serious drawbacks. As a matter of fact, room air
is sucked from the room where the fireplace is located, typically through openings
or mouths formed in the lower portion of the fireplace, is heated mainly owing to
convective heat exchange through metal walls of the combustion chamber or fireside,
and is then fed back into the room through one or more warm air delivering mouths
formed in the upper front portion of the fireplace.
[0005] Warm air released from the upper front of the fireplace is often a source of nuisance
for people standing in front of the fireplace, since they are hit by a warm air flow.
In any case, such a fireplace system is unsuitable for quickly heating room air below
the warm air delivery level, where instead a quick warming is desirable as warm air
flow obviously tends to flow upwards towards the room ceiling, thus resulting in an
undesired heat gradient being generated, at least at the initial stage of heating
a room, between the air close to the ceiling and the air below the level of the air
outlet mouth or mouths, which means uneven heating of the room.
[0006] A conventional fireplace of this type is disclosed in
US-6 050 259 patent.
[0007] The operations of sucking room air and feeding it back, once heated, into the same
room are carried out by a motor-driven fan generally driven by an electric motor,
which is designed to suck relatively cold air from the room and deliver it in a warmed
and forced condition back into the same room through the one or more delivery mouths.
[0008] To obtain a good heating efficiency of the fireplace, it is generally necessary,
besides providing an efficient heat exchange between flue gases and sucked room air,
to keep a relatively high flow of room air through the fireplace,
[0009] For obtaining this desired result, in recent years increasingly more powerful fans
have been used, which results in a considerable increase in the noise pollution caused
by large amounts of air flowing through the fan and ventilation chambers, and intake
and delivery ducts.
[0010] The main object of the present invention is to provide a gas fireplace which makes
it possible to eliminate or at least substantially reduce the above mentioned drawbacks.
Another object of the present invention is to provide a gas fireplace having optimum
efficiency, very high yield and autonomy, and suitable for quickly and evenly heating
the space where it is located.
[0011] A further object of the present invention is to provide a gas fireplace that can
be manufactured at a low production cost and can be easily installed.
[0012] These and other objects, which will better appear below, are attained by a gas fireplace
according to the present invention, comprising a support and housing frame, a gas
combustion chamber, at least one chimney duct for releasing flue gases coming from
said combustion chamber, at least one inlet duct for external comburent air leading
to said combustion chamber, a ventilation and heating circuit designed to suck environment
air, and to heat and feed it at least partly into the space where the fireplace is
located, and at least one motor-driven fan designed to operate in said ventilation
and heating circuit, characterized in that at least one silencer device is provided
along said ventilation and heating circuit.
[0013] Advantageously, said silencer device is arranged downstream of said motor-driven
fan.
[0014] Preferably, said motor-driven fan is arranged downstream of said ventilation and
heating circuit, whereby room air is sucked through one or more suction mouths provided
at at least one upper portion of the fireplace above said combustion chamber, and
fed in a warmer state into the space at at least one delivery mouth provided at at
least one lower portion located below said combustion chamber,
[0015] To increase the heat exchange efficiency between the relatively hot flue gases and
the external comburent air as well as the relatively cold room air, the external inlet
comburent air is pre-heated through heat exchange with the flue gases being discharged
along the or each chimney duct, and transfer a portion of its pre-heating heat to
the room air to be heated.
[0016] Preferably, pre-heating of external comburent air is carried out by locating the
or each chimney duct inside a respective outer comburent air feeding duct so that
a gap is formed therebetween through which external comburent air can flow, thereby
countercurrent heat exchange is obtained between flue gases and external comburent
air.
[0017] Advantageously, said gas fireplace has a hood adapted to delimit a space above said
combustion chamber for a desired room air conveyance.
[0018] Preferably, said ventilation and heating circuit comprises at least one humidifier
device for the heated air delivered into the room.
[0019] Further aspects and advantages of a gas fireplace according to the present invention
will be better apparent from the following detailed description given with reference
to the accompanying drawings, in which:
Figure 1 is a front view of a gas fireplace according to the present invention;
Figure 2 shows a side cross sectional view taken along a vertical line of the fireplace
in Figure 1 provided with a hood; and
Figure 3 is a front cross sectional view taken along a vertical line of the fireplace
in Figure 2.
[0020] With reference to the above listed Figures, a gas fireplace according to the present
invention, generally designed with reference numeral 1, comprises a support and housing
frame including a base 2, preferably covered with lining members, e.g. made of marble
or ceramic material, from which a substantially parallelepiped housing 3 rectangular
in top view rises. The housing 3 delimits a closed inner space and comprises a lower
or bottom wall 4, two side walls 5a, 5b, a rear wall 6, an upper or ceiling wall 7,
as well as a front door 8, preferably made of glass or, more preferably, ceramic glass,
in order to ensure a good heat-tight arrangement.
[0021] The inner space of the housing 3 is subdivided into a number of adjacent chambers,
as described below.
[0022] In the innest portion there is provided a combustion chamber 9, where a gas burner
10 is located, to which fuel gas can be fed through a feeding duct 11 in fluid communication
with a suitable fuel gas source (not shown in drawings), e.g. a methane gas pipe network
or a gpl feeding tank or even a bottle of another suitable liquefied gas fuel, as
it is well known in the art. The combustion chamber 9 is sealed and made of metallic
material, preferably cast iron, thereby ensuring an efficient heat exchange between
the inner and outer portions of the combustion chamber. If desired, the combustion
chamber is internally covered with refractory material. More particularly, the combustion
chamber 9 is delimited by a lower or bottom wall 12, two side walls 13a and 13b, a
rear wall 14, an upper wall or ceiling 15, and the front door 8.
[0023] Outside the combustion chamber 9 one or more ventilation chambers are delimited,
preferably a rear ventilation chamber 16, two side ventilation chambers 17a and 17b,
preferably in direct communication with the rear chamber 16, and an upper ventilation
chamber 18, owing to the presence of one or more metal partitions 19, which are located
in such a manner as to extend around the combustion chamber 9, but at a given distance
therefrom.
[0024] Advantageously, the walls of the ventilation chambers 16, 17a, and 17b can have finnings
A to enhance the heat exchange efficiency between hot flue gases and air to be heated.
[0025] Between the rear wall 6 and the side walls 5a and 5b of the housing 3 and the metal
partitions 19 one or more chambers 20 for external comburent air are delimited, which
extend at the lower portion thereof below the combustion chamber 9 between bottom
wall 12 of the latter and the bottom wall 4 of the housing 3, and lead to the burner
10, whereas at the upper portion thereof the same chambers are in fluid communication
with a metal inlet duct 21 for external comburent air.
[0026] Duct 21 has its inlet mouth 22 for external comburent air outside the space or room
to be heated where the gas fireplace 1 is located (Figure 2), and advantageously extends
through a wall P of a building,
[0027] The combustion chamber 9 at its ceiling 15 is in communication with a metal chimney
duct 23 arranged to exhaust the flue gases and preferably extends inside the inlet
duct 21 for external comburent air, thereby delimiting therewith a gap 24 suitable
for delimiting a comburent air passage, which passage is in countercurrent heat exchange
with the relatively hot flue gases coming from the combustion chamber 9. As known
in the art, the chimney duct 23 ends with an exhaust diffuser 25 beyond the inlet
mouth 22 for comburent air.
[0028] The upper ventilation chamber 18 is in communication with both the rear and the side
ventilation chambers 16, 17a, and 17b, respectively, and a plurality of upper openings
26, only one of which is shown in Figure 2, above which, in the case in which the
gas fireplace is equipped with a hood K, there is preferably provided a space S for
conveying room air sucked through one or more mouths 27 arranged in the hood K and
preferably provided with grid 28, before entering in a ventilation and hearting circuit
through openings 26.
[0029] The ventilation and heating circuit for room air also comprises, besides the ventilation
chambers 16, 17a, 17b, and 18, a motor-driven fan 30, preferably a solenoid valve
having a relatively large flow rate, whose suction side is in fluid communication
with a lower manifold 31, which is in turn in communication with the ventilation chambers
16, 17a, 17b, and 18, whereas its delivery side is connected to a feeding duct 32
for heated room air located at the base 2 below the combustion chamber 9.
[0030] The delivery duct 32 is intercepted by a silencer device 33 of any suitable type
designed to eliminate or substantially deaden noises produced in the forced air flow
inside the feeding duct 32. Downstream of the silencer device 33 there is provided
a mouth 34 for delivering heated room air into the space to be heated, optionally
together with one or more intakes for a duct (not shown in drawings) for heated room
air to be supplied to rooms adjacent to the space in which the gas fireplace 1 is
located.
[0031] At the front of the gas fireplace 1, preferably above the combustion chamber 9, a
humidifcation device 35 can be provided which comprises a water reservoir, that owing
to heat exchange with hot flue gases coming from the combustion chamber, as well as
to heat exchange with room air conveyed into the space S, in the case of a gas fireplace
provided with a hood K, evaporates, thereby causing heated air delivered into the
room in which the gas fireplace 1 is located to become less dry, and thus more pleasant.
[0032] Relatively cold external comburent air enters the fireplace through one or more wall-type
or roof-type mouths 23, flows through inlet duct 21 for comburent air, and reaches
the comburent air chamber 20, from where it flows below the combustion chamber 9 before
entering the same from below to feed the combustion of gas supplied to burner 10 through
the gas feeding duct 11.
[0033] Due to the combustion reaction, relatively hot flue gases are generated in the combustion
chamber 9, which leave the combustion chamber along the chimney 23, to be thus discharged
and dispersed in the environment through diffusor 25.
[0034] Advantageously, since the chimney duct 23 extends into inlet duct 21 for external
comburent air, as specified above, inlet air is in convective countercurrent heat
exchange relationship with the hot flue gases, which results in comburent air flowing
through the gap 24 being progressively pre-heated and the outlet flue gases being
consequently cooled.
[0035] On the contrary, room air to be heated enters the ventilation and heating circuit
of the gas fireplace 1 at the upper openings 26, or, if the gas fireplace 1 is equipped
with a hood K, through mouths 27 provided with grid 28, formed in the hood K. Owing
to the motor-driven fan 30, room air sucked into the ventilation and heating circuit
is forced to flow through ventilation chambers 16, 176a, and 17b arranged between
the combustion chamber 9 and the comburent air chamber or chambers 20. Inside the
ventilation chambers 16, 17a, 17b air is heated owing to a double heat exchange, i.
e. with the walls 13a, 13b, and 14, respectively, of the combustion chamber 9, which
are licked by hot flue gases, and the partitions 19, licked by comburent air which
was previously heated due to heat exchange with hot flue gases being discharged through
the chimney duct 23.
[0036] The delivery mouth of the fan 30 is connected, through the silencer device 33 for
eliminating any tedious noises generated in the heated air delivery flow, to one or
more heated air delivery ducts through which heated air is delivered through openings
34 in the room in which the gas fireplace 1 is located, or is also partly supplied
through suitable ducts into adjacent rooms.
[0037] The above described invention is susceptible to numerous modifications and variations
within the scope as defined by the claims.
[0038] Thus, for example, in the ventilation and heating circuit, side ventilation chambers
17a and 17b can be placed into communication with one another through one or more
tubular members 29 extending from one chamber to another through the combustion chamber
9 at the upper wall or ceiling 15 thereof. Moreover, ventilation chambers 16, 17a,
17b can be located outside the comburent air chamber 20, rather than being provided
between the external comburent air chamber 20 and the combustion chamber 20.
[0039] Furthermore, although in the above described embodiment a chimney duct 23 for discharging
flue gases and an inlet duct 21 for comburent air are arranged so as to delimit a
gap 24 therebetween for comburent air flowing through and being preheated, the present
invention also relates to an arrangement comprising a direct intake of comburent environment
air, i.e. through an comburent air inlet duct 21 for connecting the combustion chamber
9 to the external environment without preheating the inlet comburent air along the
chimney.
[0040] Of course, the silencer device 33 will also be provided upstream of the solenoid
valve 30, whereby it can operate both on the intake or delivering side thereof.
1. A gas fireplace comprising a support and housing frame (2, 3), a gas combustion chamber
(9), at least one chimney duct (23) for releasing flue gases coming from said combustion
chamber (9), at least one inlet duct (21) for external comburent air leading to said
combustion chamber (9), a ventilation and heating circuit (16, 17a, 17b, 18, 26, 29,
32) designed to suck environment air, and heat and feed it at least partly into the
space where the fireplace (1) is located, and at least one motor-driven fan (30) designed
o operate in said ventilation and heating circuit (16, 17a, 17b, 18, 26, 29, 32),
characterized in that at least one silencer device (33) is provided along said ventilation and heating
circuit (16, 17a, 17b, 18, 26, 29, 32).
2. A gas fireplace as claimed in claim 1, characterized in that said at least one silencer device (33) is arranged upstream or downstream of a respective
motor-driven fan (30).
3. A gas fireplace as claimed in claim 1 or 2, characterized in that the or each chimney duct (23) and a respective inlet duct (21) for external comburent
air are arranged one inside another thereby delimiting a gap (24) through which a
comburent air flow is in countercurrent heat exchange relationship with flue gases
flow in said chimney duct (23).
4. A gas fireplace as claimed in claim 1 or 2, characterized in that said inlet duct (21) for external comburent air is designed to feed comburent air
to said combustion chamber (9) with no pre-heating of the comburent air.
5. A gas fireplace as claimed in any previous claim, characterized in that said ventilation and heating circuit comprises at least one ventilation chamber (16,
17a, 17b, 18, 29).
6. A gas fireplace as claimed in any previous claim, characterized in that said motor-driven fan (30) has a suction side thereof in fluid communication with
at least one ventilation chamber (16, 17a, 17b) and a delivery side thereof in fluid
communication with at least one heated room air feeding duct (32).
7. A gas fireplace as claimed in any previous claim, characterized in that said at least one ventilation chamber (16, 17a, 17b) is located in heat exchange
relationship between said at least one comburent air chamber (20) and said combustion
chamber (9).
8. A gas fireplace as claimed in any previous claim, characterized in that said at least one ventilation chamber (16, 17a, 17b) is located outside said at least
one comburent air chamber (20) and in heat exchange relationship therewith.
9. A gas fireplace as claimed in any previous claim, characterized in that it comprises a hood (K) delimiting an upper space (S) for room air to be heated and
conveyed to said ventilation and heating circuit (16, 17a, 17b, 18, and 29),
10. A gas fireplace as claimed in any previous claim, characterized in that it comprises at least one humidification device (35) for heated air delivered into
the room.
11. A gas fireplace as claimed in any previous claim, characterized in that said at least one combustion chamber (16, 17a, 17b) of said ventilation and heating
circuit in heat exchange relationship with said at least one comburent air chamber
(20) and said combustion chamber (9) has a plurality of finnings (A).