U.S. patent application number 14/396937 was filed with the patent office on 2015-03-19 for catalytic unit for solid fuel burning stoves.
The applicant listed for this patent is SKAMOL A/S. Invention is credited to Thomas Kristensen, Soren Norgaard Bertel.
Application Number | 20150075510 14/396937 |
Document ID | / |
Family ID | 48536659 |
Filed Date | 2015-03-19 |
United States Patent
Application |
20150075510 |
Kind Code |
A1 |
Kristensen; Thomas ; et
al. |
March 19, 2015 |
CATALYTIC UNIT FOR SOLID FUEL BURNING STOVES
Abstract
This invention describes a stove comprising a combustion chamber
and a flue for removing exhaust from said combustion chamber, where
said combustion chamber and said flue are connected via a
passageway; said combustion chamber comprising a top and a bottom,
where said top and said bottom are connected by one or more sides;
a catalytic unit arranged between said combustion chamber and said
flue in said passageway; said catalytic unit provides a guide way
for the exhaust, where said catalytic unit comprises at least one
isolating members and at least one catalytic member, said catalytic
member comprising a first wave-like structure, said first wave-like
structure being provided on at least one catalytic surface of said
catalytic member and, in use, at least partly being in contact with
the exhaust and, where, in use, the direction of the exhaust is
substantially transverse to the waves of said first wave-like
structure.
Inventors: |
Kristensen; Thomas;
(Thisted, DK) ; Norgaard Bertel; Soren; (Skive,
DK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SKAMOL A/S |
Nykobing M |
|
DK |
|
|
Family ID: |
48536659 |
Appl. No.: |
14/396937 |
Filed: |
April 25, 2013 |
PCT Filed: |
April 25, 2013 |
PCT NO: |
PCT/DK2013/050120 |
371 Date: |
October 24, 2014 |
Current U.S.
Class: |
126/77 ; 110/203;
126/80 |
Current CPC
Class: |
F24B 1/006 20130101;
F23J 15/02 20130101 |
Class at
Publication: |
126/77 ; 126/80;
110/203 |
International
Class: |
F24B 1/00 20060101
F24B001/00; F23J 15/02 20060101 F23J015/02; F24B 15/00 20060101
F24B015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 27, 2012 |
DK |
PA 2012 70216 |
Claims
1. A stove comprising a combustion chamber and a flue for removing
exhaust from said combustion chamber (117), where said combustion
chamber and said flue are connected via a passageway; said
combustion chamber comprising a top and a bottom, where said top
and said bottom are connected by one or more sides; a catalytic
unit arranged between said combustion chamber and said flue in said
passageway; said catalytic unit provides a guide way for the
exhaust, where said catalytic unit comprises at least one isolating
member and at least one catalytic member, said catalytic member
comprising a first wave-like structure, said first wave-like
structure being provided on at least one catalytic surface of said
catalytic member and, in use, at least partly being in contact with
the exhaust and, where, in use, the direction of the exhaust is
substantially transverse to the waves of said first wave-like
structure.
2. The stove according to claim 1 wherein said catalytic member is
integrated in an exposed isolating surface of at least one
isolating member.
3. The stove according to claim 1 wherein said exposed isolating
surface of at least one isolating member facing said catalytic
member comprise a second wave-like structure, where, in use, the
direction of the exhaust is substantially transverse to the waves
of said second wave-like structure.
4. The stove according to claim 3 wherein the mutual distance
perpendicular to the intended travel direction of the exhaust is
constant between said first and said second wave-like
structures.
5. The stove according to claim 1 wherein said at least one
isolating member forms at least a part of said top of the
combustion chamber.
6. The stove according to claim 1 wherein said stove further
comprises an additional member, said additional member is arranged
in said passageway, where said additional member extends said guide
way for the exhaust and said additional member preferably is an
additional isolating member.
7. The stove according to claim 1 wherein said at least one
isolating member comprises at least one end at at least one opening
of the catalytic unit, where, in use, said exhaust enters and/or
exits said catalytic unit and that at least one of said isolating
member comprises a bent edge where the bent edge is formed at least
partly along said at least one end of said isolating member.
8. The stove according to claim 1 wherein said catalytic member is
a plate.
9. The stove according to claim 1 wherein said catalytic member is
a grid.
10. The stove according to claim 1 wherein said catalytic unit
comprises two isolating members and one catalytic member, where
said catalytic member is arranged between said two isolating
members.
11. The stove according to claim 1 wherein said exposed isolating
surface on said at least one isolating member comprises at least
one protruding portion.
12. The stove according to claim 11 wherein said at least one
isolating member comprises at least two ends at at least an inlet
and an outlet opening of said catalytic unit, where, in use, said
exhaust enters and exits said catalytic unit, said at least two
ends is connected by at least two sides and where said at least one
protruding portion is arranged along at least one of said sides of
said isolating member.
13. The stove according to claim 1 wherein said catalytic member is
coated with at least one layer of metal; said metal is located on
the surface of said catalytic member for reacting with carbon
monoxide (CO), volatile organic compounds (VOC) and particles in
said exhaust.
14. The stove according to claim 1 wherein said catalytic unit is
inclined relative to said bottom of said combustion chamber.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a solid fuel burning stove
comprising a catalytic unit.
BACKGROUND OF THE INVENTION
[0002] Wood and coal burning stoves are employed for home heating
and purposes such as cooking. However, especially the burning of
wood often results in incomplete combustion and exhaust comprising
a high amount of particles, volatile organic compounds and carbon
monoxide, all of which are a hazard to the environment.
[0003] Furthermore, the incomplete combustion results in a loss of
overall combustion efficiency.
[0004] In order to increase the combustion efficiency and minimize
the pollution from the wood burning stove, the combustion
temperature in the combustion chamber has been increased, and
catalytic converters introduced into the stove.
[0005] EP0037281 describes a wood burning stove with a combustion
chamber and a flue, where a catalytic converter is located either
in said combustion chamber or in the flue. The catalytic converter
comprises a plurality of catalytic cells with a length oriented in
the direction of the flow. The catalytic converter is a honeycomb
structure with a plurality of mutually parallel cells extending
through the structure.
[0006] EP0354674 discloses a wood burning stove with a catalytic
cell for reducing exhaust emissions from the stove. The catalytic
cell forms a secondary combustion chamber within the stove
communicating with the primary combustion chamber. Hereby the
exhaust from the primary combustion chamber is catalytically
combusted in the secondary combustion chamber.
[0007] WO85/02455 discloses an insulated secondary combustion
chamber where a mixture of exhaust gasses from the primary
combustion chamber is burned. The secondary combustion chamber can
be retrofitted on existing wood burning stoves. The retrofitted
apparatus is formed as a heat exchanger with a first and second
passageway, where the heat exchanger has an undulating shape for
better heat exchange. Insulating material is provided along one
side of the first and second passageway, respectively. A perforated
catalytic igniter is provided in the lower portion.
[0008] However, in order to achieve the most powerful reduction of
pollutants from stoves, it is important to optimise the catalytic
unit with regard to temperature and catalytic power.
[0009] Additionally, the catalytic unit is to be designed in a
manner which results in a minimal pressure drop when the exhaust
passes through the catalytic unit. If the pressure drop is too
large, the combustion in the combustion chamber will be
insufficient and result for example in a large amount of
particles.
OBJECT OF THE INVENTION
[0010] It is the object of the present invention to provide a stove
having an alternative catalytic unit for effectively minimising the
exhaust of particles, carbon monoxide (CO) and volatile organic
compounds (VOC), hereby increasing the overall combustion
efficiency and decreasing the negative effects on human health and
the environment.
DESCRIPTION OF THE INVENTION
[0011] This object is achieved by a stove comprising [0012] a
combustion chamber and a flue for removing exhaust from said
combustion chamber, where said combustion chamber and said flue are
connected via a passageway; [0013] said combustion chamber
comprising a top and a bottom, where said top and said bottom are
connected by one or more sides; [0014] a catalytic unit arranged
between said combustion chamber and said flue in said passageway;
[0015] said catalytic unit provides a guide way for the exhaust,
where said catalytic unit comprises at least two isolating members
and at least one catalytic member, [0016] said catalytic member
comprising a first wave-like structure, said first wave-like
structure being provided on at least one catalytic surface of said
catalytic member and, in use, at least partly being in contact with
the exhaust and, where, in use, the direction of the exhaust is
substantially transverse to the waves of said first wave-like
structure.
[0017] In one embodiment, the stove is a solid fuel burning stove.
The solid fuel burning stove is to be understood as a stove capable
of burning for example wood and coal. The wood and coal are burned
in a combustion chamber releasing exhaust, which is transported to
the outside of a building by a flue. The exhaust is transported via
a passageway from the combustion chamber to the flue.
[0018] The passageway can be either just a connection or a
secondary chamber for heat exchange and/or secondary combustion of
the particles present in the exhaust. The passageway may also be a
combination of both a connection and a secondary chamber.
[0019] By "heat exchange" is meant that the heat from the exhaust
is transmitted to the surroundings, whereby the temperature of the
exhaust from the fuel is decreased.
[0020] The combustion chamber comprises a top and a bottom, which
are connected via one or more sides. Solid fuel is arranged at the
bottom of the combustion chamber for burning. The exhaust obtained
during burning exits the combustion chamber through an opening in
the combustion chamber, preferable in the top or next to the top of
the combustion chamber.
[0021] A catalytic unit is arranged in the passageway for boosting
the oxidation of compounds in the exhaust from the combustion
chamber. Hereby, the amount of particles, volatile organic
compounds (VOCs) and carbon monoxide (CO) is decreased in the
exhaust.
[0022] In one embodiment, the catalytic unit is arranged just after
the combustion chamber, i.e. when the exhaust leaves the combustion
chamber, it enters the catalytic unit. When the exhaust leaves the
catalytic unit, it enters into the secondary chamber for maximal
exploitation of the heat generated in both the combustion chamber
and during the secondary combustion in the catalytic unit. From the
secondary chamber, the exhaust is directed to the flue. Thus, the
catalytic unit provides a guide way for the exhaust on its way from
the combustion chamber to the flue.
[0023] In one embodiment, the catalytic unit is arranged in the
secondary chamber of the stove. A secondary chamber is commonly
present in multiple solid burning stoves, and the catalytic unit
can be fitted into existing stoves without the necessity of
redesigning presently known stoves.
[0024] In a further embodiment, the catalytic unit forms the
secondary chamber of the stove.
[0025] In one embodiment, the catalytic unit can be retrofitted
onto existing stoves.
[0026] In another embodiment, the catalytic unit is installed in
newly produced stoves. In one embodiment, the catalytic unit
comprises a catalytic member and at least two isolating
members.
[0027] The catalytic member preferably operates at temperatures up
to 1050.degree. C. More preferably, the catalytic member operates
at temperatures between 200.degree. C. to 900.degree. C. In another
preferred embodiment, the catalytic member operates at temperatures
between 200 and 350.degree. C.
[0028] In order to maintain the temperature of the exhaust after
exiting the combustion chamber, the catalytic unit further
comprises at least one isolating member. Hereby, the temperature is
kept in a range between 200 and 900.degree. C.
[0029] By "at least one isolating member" is to be understood that
the number of isolating members enclosing the catalytic member can
be one, two, three, four, five, six etc members.
[0030] More than one isolating member can be engaged with one
another in order to secure a high temperature close to the
catalytic member and to form a catalytic unit, which forms a guide
way for the exhaust.
[0031] In one embodiment, the guide way through the catalytic unit
is a closed space except for an inlet opening and an outlet
opening.
[0032] At least an inlet opening and an outlet opening is present
in the catalytic unit for allowing the passage of exhaust into the
catalytic unit and out of the catalytic unit. Hereby, the exhaust
is able to come into contact with the catalytic surface of the
catalytic member. Advantageously, the exhaust is able to come into
contact with all catalytic surfaces of the catalytic member.
[0033] In one embodiment, the inlet opening and the outlet opening
is one opening.
[0034] In one embodiment, the inlet opening is of a width similar
to the width of the passageway. In a further embodiment, the outlet
opening is of a width similar to the width of the passageway. In a
further embodiment, the inlet opening and the outlet opening are of
a width similar to the width of the passageway.
[0035] Isolating the catalytic unit along the flow direction of the
exhaust by isolating members results in a minimal temperature loss
over the catalytic unit. Thus, an optimal reaction temperature with
regard to the catalytic process can be maintained i.e. between
200.degree. C. and 900.degree. C. Furthermore, a large pressure
loss is prevented. Therefore, the exhaust easily exits the flue
though the amount of particles, VOC and CO is diminished.
[0036] The catalytic member is provided with a first wave-like
structure on at least one catalytic surface of the catalytic
member.
[0037] As an example, the first wave-like structure can be a
sinus-shaped curve having 5 cm between the first waves and a first
wave-height of 1 cm.
[0038] In one embodiment, the distance between the first waves
differs along the catalytic unit. In a further embodiment, the
height of the first waves differs along the catalytic unit. In a
still further embodiment, both the distance between the first waves
and the height of the first waves differ along the catalytic
unit.
[0039] The first wave-like structure is arranged in a manner,
whereby the intended travel direction of the exhaust is directed
substantially transverse to the first waves. Hereby, turbulence is
induced in the exhaust flow and the exhaust flow is continuously
mixed, whereby the entire flow comes into contact with the
catalytic member. Furthermore, the catalytic area is increased.
[0040] The intended travel direction of the exhaust is to be
understood as the primary travel direction of the exhaust.
[0041] The design of the catalytic unit minimises the pressure drop
between the air intake of the combustion chamber and the end of the
flue. Preferably, the pressure drop over the catalytic unit is no
different from the pressure drop over the secondary combustion
chamber not including a catalytic unit.
[0042] In one embodiment, the catalytic unit is designed in a
manner which allows a pressure drop between the combustion chamber
and the end of the flue to be at a maximum of 12 Pa (static
pressure) according to European standards (EN13240).
[0043] In one embodiment, the stove further comprises a blower in
order to force convection. In this embodiment, the design of the
catalytic unit can be more complex and hereby introduce a
significant pressure drop.
[0044] The catalytic member can be arranged with regard to the
isolating members by either resting the catalytic member against
the surface of one of the isolating members or by small attaching
means, where the attaching means are attached to both the catalytic
member and to one or more isolating members. By using the small
attaching means, a given distance between the isolating members and
catalytic member can be maintained.
[0045] In an advantageous embodiment, said catalytic member is
integrated in an exposed isolating surface of at least one
isolating member. Hereby, is to be understood, that the catalytic
member is part of at least one of the isolating members and that
the oxidative boosting takes place at a surface of the isolating
member, where the surface is exposed to the exhaust passing through
the catalytic unit.
[0046] The catalytic member can be integrated only partly on the
exposed surfaces of the isolating members. Hereby is to be
understood that only parts of the exposed surface can be provided
with the catalytic member.
[0047] By exposed isolating surface is to be understood the surface
of the isolating member which faces the guide way for the exhaust
and hereby is exposed at least partly to the exhaust passing
through the catalytic unit.
[0048] In another embodiment, the catalytic member is only
integrated with some of the exposed surfaces i.e. if the catalytic
unit comprises two isolating members and two exposed isolating
surfaces, the catalytic member is provided only on one of the
exposed surfaces or if the catalytic unit comprises four isolating
members and four exposed isolating surfaces, the catalytic member
is provided only on one, two or three of the exposed surfaces.
[0049] In another embodiment, the catalytic member is integrated
with all of the exposed isolating surfaces i.e. if the catalytic
unit comprises two isolating members and two exposed isolating
surfaces, the catalytic member is provided on both of the exposed
isolating surfaces or if the catalytic unit comprises four
isolating members and four exposed isolating surfaces, the
catalytic member is provided on four exposed isolating
surfaces.
[0050] In one embodiment, the catalytic member is formed by adding
a metallic layer onto the exposed surface of the isolating
member.
[0051] In an alternative embodiment, the exposed isolating surface
is formed by providing the surface with a ceramic layer and a
catalytic metal layer. Hereby, the catalytic surface area is
increased due to the porous structure of the ceramic layer.
[0052] In a further advantageous embodiment, said catalytic unit
comprises said catalytic member being surrounded by one isolating
member.
[0053] In this embodiment, the isolating member is formed as a pipe
or a tube, where the catalytic member can be arranged inside the
tube. Since the isolating member is not to be assembled from more
members the catalytic member is easily installed in the stove.
Furthermore, no assemblies will be present and thus, the
temperature of the catalytic unit can be kept at a high level to
obtain optimal reduction of particles, VOC and CO.
[0054] Alternatively, the catalytic member can be an integrated
part of the exposed surface of the isolating member.
[0055] In an advantageous embodiment, said exposed isolating
surface of at least one isolating member facing said catalytic
member comprises a second wave-like structure, where, in use, the
direction of the exhaust is substantially transverse to the waves
of said second wave-like structure.
[0056] The at least one isolating member comprises at least one
isolating surface. One of the isolating surfaces faces the
catalytic member and is thus, an exposed isolating surface. Between
this exposed isolating surface and the surface of the catalytic
member, the flow of exhaust moves.
[0057] The exposed isolating surface can comprise a second
wave-like structure.
[0058] In one embodiment, the exposed isolating surface at least
partly comprises a second wave-like structure.
[0059] As an example, the second wave-like structure can be a
sinus-shaped curve having 5 cm between the second waves and a
second wave-height of 1 cm.
[0060] In one embodiment, the distance between the second waves
differs along the catalytic unit. In a further embodiment, the
height of the second waves differs along the catalytic unit. In a
still further embodiment, both the distance between the second
waves and the height of the second waves differs along the
catalytic unit.
[0061] The second wave-like structure is arranged in a manner,
whereby the intended travel direction of the exhaust is directed
substantially transverse to the second waves. Hereby, further
turbulence is induced in the exhaust flow.
[0062] An increased number of collisions between CO, VOC, particles
and oxygen at the surface of the catalytic member at a temperature
between 200 and 900.degree. C. in combination with only a minor
pressure drop over the catalytic unit are obtained by providing the
catalytic unit with both first and second wave-like structures. The
concentration of the polluting components CO, VOC and particles are
hereby efficiently decreased.
[0063] In a further advantageous embodiment, the mutual distance
perpendicular to the intended travel direction of the exhaust is
constant between said first and said second wave-like structures.
Hereby, the flow of exhaust experiences turbulence and an increased
surface area of the catalytic member along the flow path, but the
pressure drop over the catalytic unit will only be minimal allowing
an efficient flow of the exhaust through the catalytic unit and out
the flue.
[0064] Arranging the catalytic member in the middle of the
passageway will constantly force the exhaust through the catalytic
member. Hereby the number of collisions and the reduction of
emissions will be increased by only a minimal loss of pressure.
[0065] In a further advantageous embodiment, at least one isolating
member forms at least a part of the top of the combustion
chamber.
[0066] One of the isolating members or a part of one of the
isolating members can be a part of the general insulation of the
combustion chamber especially when the catalytic unit is arranged
in direct connection to the combustion chamber. Hereby, less
material is to be used for optimal insulation and combustion in the
stove.
[0067] Furthermore, using an isolating member both as part of the
combustion chamber as well as for the catalytic unit is less space
demanding, which is advantageous especially for small stoves.
[0068] In a further advantageous embodiment, said stove further
comprises an additional member, said additional member is arranged
in said passageway, where said additional member extends said guide
way for the exhaust and said additional member preferably is an
additional isolating member.
[0069] Hereby, the travelling direction of the exhaust can be
further rearranged in the passageway and an extended guide way
through the passageway is formed. Thus, the duration of the exhaust
being in the passageway is increased and hence the amount of
particles, VOC and CO decreased.
[0070] In one embodiment, the additional member is made from
isolating material. The isolating material can be the same as
described below for the isolating members of the catalytic unit.
Hereby, the high temperature between 200.degree. C. and 900.degree.
C. of the exhaust is maintained and the combustion of the
particles, VOC and CO is increased.
[0071] In a further embodiment, the material of the additional
member is the same as for the isolating members.
[0072] In a further embodiment, said additional member is a
plate-like member.
[0073] In a still further embodiment, the additional member is
arranged in a first inclined position in the passageway in relation
to the bottom of the combustion chamber maintaining the exhaust in
the passageway for a longer time either forcing the exhaust
downwards or just modifying the natural upwards movement of the
exhaust.
[0074] The additional member can be arranged either before or after
the catalytic unit in the passageway with regard to the travel
direction of the exhaust.
[0075] In one embodiment, the additional member is a part of the
catalytic unit.
[0076] In a further advantageous embodiment, said at least one
isolating member comprises at least one end at at least one opening
of the catalytic unit, where, in use, said exhaust enters and/or
exits said catalytic unit and that at least one of said isolating
member comprises a bent edge where the bent edge is formed at least
partly along said at least one end of said isolating member.
[0077] To allow the inlet and outlet of the exhaust the catalytic
unit is provided with at least one opening for the exhaust to enter
into and out of the catalytic unit, the inlet and outlet opening,
respectively.
[0078] In this embodiment, the at least one opening is provided at
the end of the catalytic unit and thus, at the end of the at least
one isolating member.
[0079] In one embodiment, the opening is both an inlet and an
outlet opening for the exhaust.
[0080] In one embodiment, the bent edge is shaped to direct the
flow of the exhaust towards the catalytic member and is thus formed
at the inlet opening of the catalytic unit.
[0081] In one embodiment, the bent edge is arranged on the isolated
member opposite of the isolating member facing the combustion
chamber, and the bent edge is arranged next to the inlet of the
catalytic unit. Thus, the bent edge prevents the exhaust from not
entering the guide way through the catalytic unit. Hence, the
connection between the catalytic unit and the combustion chamber is
automatically generated by the bent edge.
[0082] Alternatively, the bent edge is formed at the outlet opening
of the catalytic unit to direct the exhaust properly towards the
flue.
[0083] The bent edge can be formed along the entire end of the
isolating member or one or more bent edges can be formed along the
end of the isolating member i.e. each bent edge only arranged along
part of the end.
[0084] In a further advantageous embodiment, said catalytic member
is a plate.
[0085] In a still further advantageous embodiment, the plate is
arranged between by at least two isolating members, where at least
one isolating member is arranged on either side of the catalytic
member. Hereby, a thin catalytic unit can be achieved, which takes
up only a minimal amount of space and still is provided with a
large surface area.
[0086] Furthermore, a plate only introduces a minimal pressure drop
across the catalytic unit.
[0087] In one embodiment, the thickness of the plate is preferably
between 0.1 to 3 cm. In a further embodiment, the thickness of the
plate is preferably between 0.5 and 2 cm. In a still further
embodiment, the thickness of the plate is approximately 1 cm. In a
still further embodiment, the thickness of the plate is preferably
between 0.01 and 3 cm. In a still further embodiment, the thickness
of the plate is preferably between 0.05 and 1 cm. In a still
further embodiment, the thickness of the plate is preferably
between 0.1 and 0.2 cm.
[0088] In a further advantageous embodiment, said catalytic member
is a grid. Hereby, the total surface area of the catalytic member
is enlarged, and thereby the capacity of the catalytic member for
promoting reduction of particles, VOC and CO.
[0089] The first wave-like structure of the catalytic member
introduces turbulence. Hence, the flow of exhaust is, besides
continuously mixing the exhaust, also able to pass through the
openings of the grid, and e.g. particles are thus capable of being
transported by the exhaust on both sides of the catalytic member as
well as from one side to the other side. Efficient contact is
therefore established between the components of the exhausts and
all surfaces of the grid.
[0090] Furthermore, introducing a grid as the catalytic member
lowers the pressure drop across the catalytic unit.
[0091] In one embodiment, the grid is a plate.
[0092] Potentially the passage through the grid can be clogged up
due to the particles in the exhaust. However, having both the first
and second wave-like structures increases the turbulence of the
exhaust to a degree, which reduces the risk of the grid being
clogged up. Thus, the catalytic effect of the catalytic member can
be exploited continuously without the risk of the grid clogging up
whereby the catalytic effect would decrease or the guide way clog
up whereby the exhaust would not be able to exit the combustion
chamber.
[0093] In a further advantageous embodiment, said catalytic member
is arranged between two isolating members. Hereby, is to be
understood that the catalytic unit comprises two isolating members
and one catalytic member, where the catalytic member is arranged
between the two isolating members. In one embodiment, the isolating
members are plate-like members, where the plate-like members
comprises two ends each at the inlet and outlet opening of the
catalytic unit, respectively. The isolating members further
comprise two sides each, connecting the ends of the isolating
members. Each of the plate-like members is arranged on either side
of a catalytic member in the form of a plate i.e. the catalytic
member is sandwiched between the two isolating members.
[0094] Advantageously, the catalytic member is a plate and a
grid.
[0095] In a further advantageous embodiment, said exposed isolating
surface on said at least one isolating member comprises at least
one protruding portion.
[0096] By providing at least one protruding portion on the exposed
isolating surface, a guide way is automatically created between
isolating members. The size of the guide way can easily be changed
by changing the size of the protruding portions. In one embodiment,
the catalytic member is arranged in the guide way.
[0097] The top of the at least one protruding portion rests against
the exposed isolating surface of the opposite arranged isolating
member. Alternatively, the top of the at least one protruding
portion arranged at a first isolating member can rest against the
top of another protruding portion arranged at a second isolating
member.
[0098] In a still further advantageous embodiment, said at least
one isolating member comprises at least two ends at at least an
inlet and an outlet opening of said catalytic unit, where, in use,
said exhaust enters and exits said catalytic unit, said at least
two ends is connected by at least two sides and where said at least
one protruding portion is arranged along at least one of said sides
of said isolating member.
[0099] To allow the inlet and outlet of the exhaust the catalytic
unit is provided with an inlet and an outlet opening, respectively.
In this embodiment, the at least one opening is provided at the end
of the catalytic unit and thus, at the end of the at least one
isolating member. The ends of the isolating members are connected
by isolating sides to form the isolating member. Along at least
part of the sides protruding portions can be provided.
[0100] A space will be formed between the isolating members when an
isolating member engages with another isolating member for forming
a catalytic unit if at least one side of one of the isolating
members is provided with protruding portions. The exhaust travels
through this space which forms a guide way for the exhaust.
[0101] In one embodiment, the catalytic unit comprises two
isolating members where both members comprise protruding portions.
The protruding portion of the first isolating member and the
protruding portion of the second isolating member engage during the
formation of a catalytic unit. Hereby, a space between the exposed
isolating surfaces is created.
[0102] In one embodiment, the catalytic member can be retained
between isolating members by being arranged between the protruding
portions and hereby being retained in position within the catalytic
unit.
[0103] In a further embodiment, the catalytic member is retained
between the isolating members by being arranged between the
protruding portions of one of the isolating members and the surface
of the other isolating member where the two isolating members
engage.
[0104] In a further embodiment, the catalytic member is arranged in
a recess formed along the sides of at least one of the isolating
members. Hereby, the engagement between the isolating members is
not influenced by the fact that part of the catalytic member is
present where the isolating members engage. Furthermore, the
catalytic member is kept in place by engaging with the recess of
the member.
[0105] In a further embodiment, the recess is provided in the at
least one protruding portion in at least one of the isolating
members.
[0106] In a further advantageous embodiment, said catalytic member
is coated with at least one layer of metal; said metal is located
on the surface of said catalytic member for reacting with particles
in said exhaust. In a still further advantageous embodiment, said
metal is palladium, platinum, cerium, rhodium, zinc, cupper or a
mixture hereof.
[0107] Hereby is to be understood that the catalytic member can
comprise one, two, three, four etc. layers of metal.
[0108] In one embodiment, the layer of metal fully coats the
catalytic member.
[0109] In a further embodiment, the layer of metal partly coats the
catalytic member.
[0110] By coating the entire surface of the catalytic member with
at least one metal layer, the catalysing compound will be
distributed over the entire surface of the catalytic member and
will be as effective as possible.
[0111] The metal can be provided in combination with a ceramic
monolith layer. The ceramic monolith is porous. Therefore, the
ceramic monolith has a high surface area pr. volume upon which
surface the metal can be coated. Hence, a large catalytic area can
be obtained. Thus, using both ceramic monolith and metal increases
the catalytic activity of the catalytic member.
[0112] In one embodiment, the catalytic member has a steel core,
preferably of stainless steel, where the steel core is coated with
a ceramic monolith layer comprising Al.sub.2O.sub.3 or SiO.sub.2
and a metal layer.
[0113] In another embodiment, the catalytic member has a core of a
ceramic monolith layer comprising Al.sub.2O.sub.3 or SiO.sub.2.
[0114] As a catalytic material can be used precious metals such as
platinum, palladium, rhodium or metal oxides of one or more of the
following metals: chromium, iron, molybdenum, wolfram, manganese,
cobalt, copper, nickel, zinc.
[0115] In a further advantageous embodiment, said catalytic unit is
inclined relative to said bottom of the combustion chamber. Thus,
the catalytic unit is arranged in a second inclined position in the
passageway maintaining the exhaust in the catalytic unit for a
longer time, either forcing the exhaust downwards or just modifying
the natural upwards movement of the exhaust. The catalytic unit is
inclined with a given angle relative to the bottom of the
combustion chamber.
[0116] In a first embodiment, the angle is between 0-70.degree.. In
a second embodiment, the angle is between 0-60.degree.. In a third
embodiment, the angle is between 0-45.degree.. In a fourth
embodiment, the angle is between 1-70.degree.. In a fifth
embodiment, the angle is between 1-60.degree.. In a sixth
embodiment, the angle is between 1-45.degree.. In a seventh
embodiment, the angle is between 15-70.degree.. In an eight
embodiment, the angle is between 25-60.degree.. In a ninth
embodiment, the angle is between 35-45.degree..
[0117] In a further advantageous embodiment, said catalytic unit is
downwardly inclined for forcing a downwardly movement of the
exhaust. The free movement of the exhaust is upwards due to the
temperature of the exhaust among other things. By forcing the
direction of the exhaust to be downwards in an inclined angle, the
exhaust is forced to flow in a direction different from the free
movement. Thus, the exhaust will maintain in the catalytic unit for
a longer time period whereby the secondary combustion will be
increased and fewer particles, VOC and CO will be directed to the
environment.
[0118] In one embodiment, the catalytic unit and the additional
member are inclined relative to the bottom of the combustion
chamber having a substantially similarly angle. Thus, the isolating
members and the additional member are substantially parallel.
[0119] In a further advantageous embodiment, said isolating members
are made of vermiculite. Vermiculite is a natural mineral that
expands with the application of heat. Vermiculite is formed by
weathering or hydrothermal alteration of biotite or phlogopite.
[0120] Vermiculite is a fire resistant material which can cope with
high temperatures without being damaged and which in addition shows
high isolating properties and non-reactivity against contents in
the exhaust from solid fuel burning stoves.
[0121] Alternatively, Calcium Silicate, Perlite and moler earth
(diatomaceous earth) can be used for the isolating members. All of
which are fire resistant material which can cope with high
temperatures as described for Vermiculite. Furthermore, these
materials along with Vermiculite are of an insulating nature
resulting in the isolating member being an insulating member as
well. This further has the advantage that the exhaust travelling
through the catalytic unit can be maintained in the high end of the
temperature range. This results in combustion automatically along
with combustion due to the catalytic member and the system is kept
adiabatic. Furthermore, it results in the temperature range between
200.degree. C. and 900.degree. C. can be kept for a longer time
period why the catalytic process can be maintained for a longer
period of time. Thus, more efficient removal of CO, VOC and
particles from the exhaust is achieved.
[0122] In a further advantageous embodiment, iron and iron alloys
including steel, nickel, chromium, cobalt, molybdenum, titanium,
wolfram, vanadium and other temperature resistant metals can be
used for the isolating members as well as alloys comprising one or
more of these metals. The advantages of these metals and the alloys
to be used are that they can cope with high temperatures as well as
they are relative easily shaped.
DESCRIPTION OF THE DRAWING
[0123] FIG. 1 illustrates a first embodiment of a catalytic
unit;
[0124] FIG. 2 illustrates a solid fuel burning stove comprising a
first embodiment of a catalytic unit;
[0125] FIG. 3 illustrates a close-up of the first embodiment of the
catalytic unit as illustrated in FIG. 2;
[0126] FIG. 4 illustrates a solid fuel burning stove comprising a
second embodiment of a catalytic unit;
[0127] FIG. 5 illustrates a close-up of the second embodiment of
the catalytic unit as illustrated in FIG. 4A;
[0128] FIG. 6 illustrates a solid fuel burning stove comprising a
third embodiment of a catalytic unit;
[0129] FIG. 7 illustrates a fourth embodiment of a catalytic
unit;
[0130] FIG. 8 illustrates a fifth embodiment of a catalytic
unit.
DETAILED DESCRIPTION OF THE INVENTION
[0131] FIG. 1 illustrates a first embodiment of a catalytic unit
101 comprising a catalytic member 103 and two isolating members
105.
[0132] The catalytic member 103 is shaped as a plate and comprises
a first wave-like structure 107.
[0133] The two isolating members 105a,b are plate-like members and
are arranged on either side of the catalytic member 103. The
surface 104a,b of the isolating members 105a,b facing the catalytic
member is provided with a second wave-like structure 109a,b. The
two isolating members each comprise two ends 110a,b,c,d and two
sides 108a,b,c,d.
[0134] Furthermore, one of the isolating members 105b comprises a
bent edge 111 along the end of the isolating member 105b. The bent
edge 111 secures the direction of the exhaust from the combustion
chamber and into the space 113 between the two isolating members
105a,b as illustrated in FIG. 2. This isolating member 105b further
comprises protruding portions 106, which rests against the other
isolating member 105a, when the isolating members 105a,b are
assembled to form a catalytic unit 101.
[0135] FIG. 2 illustrates a cross-section of a solid fuel burning
stove 115 comprising a first embodiment of a catalytic unit 101.
The catalytic unit 101 is arranged in the passageway 118 between
the combustion chamber 117 and the flue 119. In this illustration,
the intended travel direction of the exhaust 121 is shown for
illustration purposes alone as a white band moving in the direction
of the arrow. The exhaust 121 enters the catalytic unit 101 through
the inlet opening 112 and exits through the outlet opening 114. For
illustration purposes and in order to illustrate the inlet opening
112 the right side of the stove is removed in this figure.
[0136] The combustion chamber 117 comprises a top 123 and a bottom
122 connected by sides 124.
[0137] The exhaust 121 travels from the combustion chamber 117 to
the catalytic unit 101, where the bent edge 111 of the catalytic
unit 101 prevents the exhaust 121 from moving further up and
directs the exhaust 121 in between the isolating members 105a,b for
contact with the catalytic member before the exhaust 121 exits the
catalytic unit 101 and travels towards the flue 119.
[0138] In this embodiment, one of the isolating members 105a forms
the top 123 of the combustion chamber 117, as well as being an
isolating member 105a of the catalytic unit 101.
[0139] A close-up of the first embodiment of the catalytic unit 101
in use is illustrated in FIG. 3 which is a close-up of the region
defined by the circle A defined in FIG. 2.
[0140] In this close-up, it is illustrated how the catalytic member
103 is arranged between the two isolating members 105a,b, with the
mutual distance 125 being constant between the first wave-like
structure 107 and the second wave-like structure 109a,b i.e. that
the top of the first waves correlates with the top of the second
waves.
[0141] Furthermore, it is illustrated how the two isolating members
105a,b engage with one another at the sides of the catalytic unit
101 due to the protruding portion 106 of one of the isolating
members 105b.
[0142] The close-up, furthermore, illustrates how the exhaust 121
is able to pass between the catalytic member 103 and the isolating
members 105a,b on both sides of the catalytic member 10 i.e. both
between the first isolating member 105a and the catalytic member
103 as well as between the second isolating member 105b and the
catalytic member 103. In addition, the exhaust 121 is able to pass
through the catalytic member 103. The catalytic member 103 can for
example be a grid.
[0143] FIG. 4 illustrates a cross-section of a solid fuel burning
stove 215 comprising a second embodiment of a catalytic unit 201.
The catalytic unit 201 is arranged between the combustion chamber
217 and the flue 219. In this illustration, the intended travel
direction of the exhaust 221 is shown for illustration purposes
alone as a white band moving in the direction of the arrow. For
illustration purposes and in order to illustrate the inlet opening
the right side of the stove is removed in this figure.
[0144] The exhaust 221 travels from the combustion chamber 217 to
the catalytic unit 201, where the bent edge 211 of the catalytic
unit 201 prevents the exhaust 221 from moving further up and
directs the exhaust 221 in between the isolating members 205a,b for
contact with the catalytic member 203.
[0145] In this embodiment, an additional member 227 is arranged
after the catalytic unit 201 with regard to the travel direction of
the exhaust forcing the exhaust 221 to travel in a space between
the additional member 227 and one of the isolating members 205b
before the exhaust 221 travels towards the flue 219.
[0146] Advantageously, the additional member 227 is an additional
isolating member, in order to maintain a high temperature of the
exhaust 221. Increasing the travelling path of the exhaust 221
through the catalytic unit 201 reduces the amount of particles CO
and VOCs in the final exhaust 221 leaving the stove 215.
[0147] In this embodiment, one of the isolating members 205a forms
the top 223 of the combustion chamber 217, as well as being an
isolating member 205a of the catalytic unit 201.
[0148] A close-up of the second embodiment of the catalytic unit
201 in use is illustrated in FIG. 5 which is a close-up of the
region defined by the circle B defined in FIG. 4.
[0149] In this close-up, it is illustrated how the catalytic member
203 is arranged between the two isolating members 205a,b, with the
mutual distance 225 being constant between the first wave-like
structure 207 and the second wave-like structure 209a,b, i.e. that
the top of the first waves correlates with the top of the second
waves.
[0150] The close-up illustrates how the exhaust 221 passes between
the catalytic member 203 and the isolating members 205a,b.
Furthermore, it is illustrated how the direction of the exhaust 221
is changed by the additional member 227 in the passageway 218.
Hereby, the time spent by the exhaust 221 in the passageway 218
before it enters the flue is increased. Thus, the amount of
particles VOC and CO in the exhaust 221 is reduced further before
it exits the stove via the flue.
[0151] FIG. 6 illustrates a cross-section of a solid fuel burning
stove 315 comprising a third embodiment of a catalytic unit 301.
The catalytic unit 301 is arranged between the combustion chamber
317 and the flue 319. In this illustration, the intended travel
direction of the exhaust 321 is shown for illustration purposes
alone as a white band moving in the direction of the arrow.
[0152] In this embodiment, an additional member 327 is arranged in
the passageway 318, where the additional member 327 is part of the
top 323 of the combustion chamber 317. The exhaust 321 is forced
downwards from the combustion chamber 317 between the additional
member 327 and one of the isolating members 305b, before it
interacts with the catalytic member 303 between the two isolating
members 305a,b of the catalytic unit 301 and enters into the flue
319.
[0153] One of the isolating members 305b comprises a bent end 311.
In this embodiment, the bent end 311 directs the exhaust 321 out of
the catalytic unit 301 and towards the flue 319.
[0154] FIG. 7 illustrates a fourth embodiment of a catalytic unit
401 comprising a catalytic member 403 and two isolating members
405a,b.
[0155] The catalytic member 403 is integrated with the exposed
isolating surface 404a of one of the isolating members 405a and
comprises a first wave-like structure.
[0156] In a further embodiment, a catalytic member 403 can be
provided on the exposed isolating surface 404b of the other
isolating member 405b as well.
[0157] Furthermore, one of the isolating members 405b comprises a
bent edge 411 along the end of the isolating member 405b. The
isolating member 405b further comprises protruding portions 406,
which rests against the other isolating member 405a, when the
isolating members 405a,b are assembled to form a catalytic unit
401.
[0158] FIG. 8 illustrates a fifth embodiment of a catalytic unit
501 comprising a catalytic member 503 and one isolating member
505.
[0159] The catalytic member 503 is shaped as a plate and comprises
a first wave-like structure. The isolating member 505 surrounds the
catalytic member 503 but leaves an outlet and an inlet opening for
the exhaust to enter and exit the catalytic unit 501.
* * * * *