CA1155017A - Stove - Google Patents

Stove

Info

Publication number
CA1155017A
CA1155017A CA000377324A CA377324A CA1155017A CA 1155017 A CA1155017 A CA 1155017A CA 000377324 A CA000377324 A CA 000377324A CA 377324 A CA377324 A CA 377324A CA 1155017 A CA1155017 A CA 1155017A
Authority
CA
Canada
Prior art keywords
combustion
chamber
secondary chamber
improvement
air
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA000377324A
Other languages
French (fr)
Inventor
Morten H. Soma
Tor A. Oftedal
Stdle Rustad
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AKSJESELSKAPET JOTUL
Original Assignee
AKSJESELSKAPET JOTUL
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by AKSJESELSKAPET JOTUL filed Critical AKSJESELSKAPET JOTUL
Application granted granted Critical
Publication of CA1155017A publication Critical patent/CA1155017A/en
Expired legal-status Critical Current

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23BMETHODS OR APPARATUS FOR COMBUSTION USING ONLY SOLID FUEL
    • F23B5/00Combustion apparatus with arrangements for burning uncombusted material from primary combustion
    • F23B5/04Combustion apparatus with arrangements for burning uncombusted material from primary combustion in separate combustion chamber; on separate grate
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23BMETHODS OR APPARATUS FOR COMBUSTION USING ONLY SOLID FUEL
    • F23B10/00Combustion apparatus characterised by the combination of two or more combustion chambers
    • F23B10/02Combustion apparatus characterised by the combination of two or more combustion chambers including separate secondary combustion chambers
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23BMETHODS OR APPARATUS FOR COMBUSTION USING ONLY SOLID FUEL
    • F23B90/00Combustion methods not related to a particular type of apparatus
    • F23B90/04Combustion methods not related to a particular type of apparatus including secondary combustion
    • F23B90/08Combustion methods not related to a particular type of apparatus including secondary combustion in the presence of catalytic material
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23LSUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
    • F23L17/00Inducing draught; Tops for chimneys or ventilating shafts; Terminals for flues
    • F23L17/005Inducing draught; Tops for chimneys or ventilating shafts; Terminals for flues using fans
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24BDOMESTIC STOVES OR RANGES FOR SOLID FUELS; IMPLEMENTS FOR USE IN CONNECTION WITH STOVES OR RANGES
    • F24B1/00Stoves or ranges
    • F24B1/006Stoves or ranges incorporating a catalytic combustor
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24BDOMESTIC STOVES OR RANGES FOR SOLID FUELS; IMPLEMENTS FOR USE IN CONNECTION WITH STOVES OR RANGES
    • F24B1/00Stoves or ranges
    • F24B1/02Closed stoves
    • F24B1/026Closed stoves with several combustion zones
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24BDOMESTIC STOVES OR RANGES FOR SOLID FUELS; IMPLEMENTS FOR USE IN CONNECTION WITH STOVES OR RANGES
    • F24B5/00Combustion-air or flue-gas circulation in or around stoves or ranges
    • F24B5/02Combustion-air or flue-gas circulation in or around stoves or ranges in or around stoves
    • F24B5/021Combustion-air or flue-gas circulation in or around stoves or ranges in or around stoves combustion-air circulation
    • F24B5/025Supply of secondary air for completing combustion of fuel
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02ATECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A40/00Adaptation technologies in agriculture, forestry, livestock or agroalimentary production
    • Y02A40/90Adaptation technologies in agriculture, forestry, livestock or agroalimentary production in food processing or handling, e.g. food conservation
    • Y02A40/924Adaptation technologies in agriculture, forestry, livestock or agroalimentary production in food processing or handling, e.g. food conservation using renewable energies
    • Y02A40/928Cooking stoves using biomass

Abstract

ABSTRACT

In order to render the secondary combustion more complete in a stove for burning solid fuel, the stove is provided with heat insulated combustion chamber.

Description

~550~7 The present invention relates to an improve-ment in stoves for combustion of solid fuel for example wood, coke, coal etc., comprising a primary combustion chamber and a secondary combustion chamber, both chambers with separate supply of combustion air.
Attempts have been made with previously known stoves of this type to achieve an after combustion of incompletely burned gases by supplying secondary air to same in the combustion chamber. Tests have, however, shown that the effect aimed at very rarely is obtained in small stoves and that if the result is obtained, it is due to particularly advantageous circumstances.
Due to the signs of a future shortage of energy recently, the interest has increased in utilization of forest products as a source for domestic heating.

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. ~
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~.~55~7 There will then be a demand for a stove which without pollution of the environments, is able to burn forest products and similar fuels with the highest possible efficiency and the best possible degree of controlled combustion.
It is a feature of this type of stoves that the fuel undergoes an incomplete (pyrolytic) combus-tion at a comparatively low temperature in a primary chamber. In this process inflammable gases (pyro-lytic gases) are liberated at a rate which is depen-dent on the temperature and the form and composition of the fuel. The temperature in the primary chamber is dependent on the rate of combustion which takes place therein, and consequently dependent on the supply of primary air and the heat insulation of the primary chamber. The total potential energy dissipation will consequently be the sum of the intensity of the primary combustion and the heating value of the pyrolytic gases. A controlled dissi-pation of energy requires at all times an adjustment of the quantity of primary air and the insulation of the primary chamber to the fuel which is in use.
In order to secure complete combustion of the pyrolytic gases and thereby obtain a high efficiency it will be necessary to supply secondary air to the gases under controlled conditions ~550~7 concerning quantity, temperature and resting tirne.
The combustion can in an effective manner take place in a separate secondary chamber with suitable heat insulation and supply of air.
The purpose of the present invention is consequently to provide a stove for combustion of solid fuel in which the combustion takes place in two stages, viz. firstly in a primary chamber and thereafter in a secondary chamber in such a manner that a high efficiency of the stove is obtained, and the stove should further be so designed that a con-trolled combustion is obtained.
According to the invention this is achieved by an improvement in stoves of the previously men-tioned kind, which is characterized in that both chambers are thermally insulated in such a manner that the production of pyrolytic gases in the primary cham-ber takes place within a predetermined space, and that the temperature in the secondary chamber is sufficiently high to cause a complete combustion of all pyolytic gases. Usually the highest temperature is required in the secondary chamber, and this suggests a better heat insulation for this chamber than in primary chamber.
Another feature of the invention is that the secondary chamber is designed as a two stage combustion ~S50~7 chamber. The size of an optimal secondary chamber will be denendent on the energy dissipation of the stove. A two-stage secondary chamber will thereby ensure good secondary combustion over a wide range of adjustment, as the combustion with low dissipations will take place in the first stage and at higher dis-sipations the combustion will be completed in the second stage.
A further feature of the invention consists in the provision of a heat exchanger surface between an inlet passage for secondary air, and an outlet passage for the hot combustion gases from the secondary chamber in order to preheat the combustion air admitted to the secondary chamber.
Another feature of the invention is that the secondary air passage opens out in the space between the primary and the secondary chamber.
A preferred embodiment of the invention is characterized in that the secondary air passage lS located in the partition between the primary chamber and the secondary chamber and in that the passage is insulated against the primary chamber and has a heat exchanger surface towards the secondary chamber. The result is a pre-heating of the secondary air.

. . .

; ~ .
: ' ' ;' , ~ ':
, ~ ~55017 Still another feature of the invention is that a source of heat is located in the secondary chamber or in the air supply passage to the secondary chamber, the source of heat being supplied with external energy and may, for example be an electric heating element. The energy dissipated by this source of heat can in accordance with the invention, be controlled by a) the temperature in the secondary chamber, or, b) the temperature rise in the secondary chamber, or c) the temperature in the primary chamber or d) a combination of the parameters (a,b,c).
In order to lower the ignition temperature for the gases in the secondary chamber it is a feature of the present invention that the secondary chamber can be provided with a catalyst. An alternative to this feature is that the secondary chamber is provided with plates, rods or similar means having a large thermal inertia so that ignition of combustion gases will take place easier than with a free gas atmosphere.
In order to ensure a self-controlled combus-tion process with high efficiency under all conditions independent of the type of fuel or form or varying draft conditions, one feature of the invention may be that-a fan is provided to ensure a uniform air _ 5 _ ; ' ' `

1~551)17 upply to the combustion. In an advantageous embodiment the fan is driven by a thermoelectric element positioned on one of the walls in one of the combustion chambers, preferably the secondary chamber. The fan can be controlled by a thermo-stat.
The invention will in the following be explained with reference to the diagrammatic drawing which shows one embodiment of the invention.
The stove shown as an example, consists of a primary chamber 1, in which at least the top wall
2 is insulated. It is, however, possible to insulate also the side walls if this should prove necessary in order to increase the temperature in the primary chamber when a predetermined rate of combustion is desired. Combustion air to the primary chamber 1 is drawn through draft openings 4 in the front of the stove.
The combustion gases from the primary chamber 1 is conveyed through an opening 5 at the rear wall
3 into the secondary chamber 6. This chamber is constructed as a two-stage chamber in which the combustion when the energy dissipation is low, takes place in stage 1, while the combustion will be com-pleted in stage 2 when the enerqy dissipation is high.
Combustion air to the secondary chamber is drawn ~sso~

in through a draft opening 7 in the front of the stove to a passage 8 in the top wall of the primary chamber 2. The supply of combustion air is so adjusted that the primary air and secondary air is controlled simultaneously. The passage 8 is insulated against the primary chamber as shown on the drawing, but is provided with a heat exchanger surface 9 towards the outlet passage 10 from the secondary chamber. The secondary chamber has a good thermal insulation, so that sufficiently-high temperatures (750-1000C) are obtained therein.
To ensure ignition with a complete combustion of the combustion gases in the secondary chamber, viz. that the temperature will be higher than the ignition temperature for the gases, a heating element 12 with external supply of energy can be used. The heating element 12 can be an electric heating element as in the shown embodiment, or the heating element can be an oil burner, gas burner etc. The heating element can be located in the supply passage 8 or the secondary air instead of in the secondary chamber proper. As mentioned above the secondary chamber may have a catalytic surface, for example a platinum or rhodium compound so that the ignition temperature for the combustion gases is lowered.

"~,',J 7 ~SS017 The secondary chamber can also be provided with plates, rods or similar means having a certain thermal inertia, so that the ignition of the combustion gases will take place easier than in a free gas atmosphere. It should be pointed out that the provision of heating element, catalyst or rod or similar means with thermal inertia can be used alone or in combination.
The hot gases from the secondary chamber 6 is conveyed out through the outlet 10, re-enters at the forward edge of the top wall 1 and flows through a passage 13 on the upper side of the top wall 11 to the flue 14. From the outlet of the passage 10 to the flue the combustion gases dissipate the largest possible quantity of heat, and the passage 13 is therefore provided with a heat exchanger for transfer of the heat to the environments.
The flue 14 may be provided with a fan 15 which could be supplied with electric current from a thermocouple 16 located on the hot wall surface of the passage 13. The thermocouple will generate an electric current which is dependent on the tempe-rature difference between the hot side of the wall and the environments. The fan 15 can be controlled by a termostat so that the supply of combustion air ~1550~7 is made dependent on a desired room temperature.
The starting of a cold stove can be made with a booster battery as the thermocouple does not gene-rate any current, or natural draft through the flue can be utilized.
The external supply of energy to the secondary chamber will not be required at all time.
To control this supply of energy the following parameters should be taken into account:
a) the temperature in the secondary chamber.
If this temperature falls below 800C, supply of external energy is required of combustion gas still is flowing from the primary chamber. A temperature sensor could then be provided in the secondary chamber.
b) Temperature rise from inlet to outlet in the secondary combustion zone. A positive value which is not due to supply of energy, indicates that combustion gas to be burned still is flowing, c) The temperature in the primary chamber.
A low limiting value indicates that the stove has no more fuel and therefore there is no need for external supply of energy.
By combination of these parameters in the form of for example electrical signals from thermi-_g_ ~550~7 stors or similar means it is possible to achieve a fully automatic and complete combustion of allinflammable gas.

:::
~: ~

,

Claims (12)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. Improvement in a stove for combustion of solid fuel, comprising a primary combustion chamber, and a secondary two stage combustion chamber, each said combustion chambers having separate supply of combustion air and both chambers being thermally insulated with higher insulation efficiency in the secondary chamber than in the primary chamber.
2. Improvement as claimed in claim 1, having a heat exchanger surface between an inlet passage for secondary air and an outlet passage for the hot combustion gases from the secondary chamber in order to preheat the combustion air to the secondary chamber.
3. Improvement as claimed in claim 2, the passage for supply of air to the secondary chamber opening into the space between the primary chamber and the secondary chamber.
4. Improvement as claimed in claim 2, the air passage for supply of air to the secondary chamber being located in a partition between the primary chamber and the secondary chamber and the outlet for the secondary chamber, and has heat exchanger surface towards the outlet.
5. Improvement as claimed in claim 1, the volume, insulation and the supply of combustion air to the primary chamber, being dimensioned to result in a uniform rate of combustion and pyrolysis in order to produce a correctly adapted quantity of unburned gases, i.e. CO which is conveyed to the secondary chamber.
6. Improvement as claimed in claim 1, the volume, insulation and supply of secondary air to the secondary chamber being dimensioned to achieve ignition and complete combustion of the pyrolitic gases.
7. Improvement as claimed in claim 1, the secondary chamber or the supply passage for secondary air being provided with a heat source with supply of external energy.
8. Improvement as claimed in claim 1, the secondary chamber being provided with a catalyst, so that the ignition temperature for the gases in chamber is lowered.
9. Improvement as claimed in claim 1, the secondary chamber being provided with plates, rods or similar means having a certain thermal inertia so that the ignition of combustion gases will take place easier than with free gas atmosphere.
10. Improvement as claimed in claim 1, having a fan to ensure uniform air supply to the combustion, so that controlled combustion is achieved.
11. Improvement as claimed in claim 10, the fan being driven by a thermocouple provided at one of the walls in one of the combustion chambers or at the outlet from the secondary chamber.
12. Improvement as claimed in claim 7, the heat source being controlled by:
a) the temperature in the secondary chamber or b) the temperature rise in the secondary chamber or c) the temperature in the primary chamber or d) a combination of the above parameters.
CA000377324A 1980-05-13 1981-05-11 Stove Expired CA1155017A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO801421A NO146444C (en) 1980-05-13 1980-05-13 DEVICE BY OVEN.
NO801421 1980-05-13

Publications (1)

Publication Number Publication Date
CA1155017A true CA1155017A (en) 1983-10-11

Family

ID=19885484

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000377324A Expired CA1155017A (en) 1980-05-13 1981-05-11 Stove

Country Status (17)

Country Link
JP (1) JPS576205A (en)
BE (1) BE888739A (en)
CA (1) CA1155017A (en)
CH (1) CH654645A5 (en)
DE (1) DE3117290A1 (en)
DK (1) DK210481A (en)
ES (1) ES502191A0 (en)
FI (1) FI65666C (en)
FR (1) FR2482702B1 (en)
GB (1) GB2081888B (en)
IE (1) IE51048B1 (en)
IT (1) IT1137009B (en)
LU (1) LU83344A1 (en)
NL (1) NL8102249A (en)
NO (1) NO146444C (en)
PT (1) PT73025B (en)
SE (1) SE446904B (en)

Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4651709A (en) * 1982-12-23 1987-03-24 Hellmut Schnetker Fuel burning stove
JPS6068301U (en) * 1983-10-14 1985-05-15 株式会社テクロツク stove
GB8519577D0 (en) * 1985-08-03 1985-09-11 Nova Stove Ltd Heating apparatus
FR2641056A1 (en) * 1988-12-23 1990-06-29 Fondis Sa Improved postcombustion method with rapid triggering for solid fuels and means intended for implementing it
RU2134838C1 (en) 1999-01-14 1999-08-20 Скроцкий Виктор Георгиевич Furnace
CN101151492B (en) * 2005-03-29 2011-07-06 皇家飞利浦电子股份有限公司 Improvements in cooking stoves
AT503815B1 (en) * 2006-09-27 2008-01-15 Gs Components Handelsgmbh Power regulator for solid fuel heated chimney ovens and stoves in combination with oxidation catalyst, comprises combustion air that is divided in two air channels using regulators
GB2466229A (en) * 2008-12-15 2010-06-16 Graham Thornhill Fuel burning stove with directed air vents to produce air rotation in combustion chamber
JP5985995B2 (en) * 2013-01-16 2016-09-06 株式会社岡本 Wood-burning stove
DE102014104778A1 (en) * 2014-04-03 2015-10-08 Mayr Heiztechnik E.K. wood stove
JP6334298B2 (en) * 2014-07-04 2018-05-30 株式会社ダイセル Smoke generator
GB201417050D0 (en) * 2014-09-26 2014-11-12 Island Pellet Stoves Ltd Stove
FR3033625B1 (en) * 2015-03-09 2018-10-19 Supra SOLID FUEL BURNER AND HEATING APPARATUS COMPRISING SUCH A BURNER
USD982445S1 (en) 2021-01-21 2023-04-04 Graham Packaging Company, L.P. Grooved container
CN113339846B (en) * 2021-06-03 2023-07-21 韩宇泉 Heating structure of heating furnace and heating furnace

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1077373A (en) * 1900-01-01
DE385496C (en) * 1922-09-26 1923-11-23 Heinrich Tritschler Herd Und O Half gas firing for ovens, stoves, etc. Like. With suction of the carbonization gases formed in the filling chamber after the flame has been extracted
GB1059345A (en) * 1962-11-22 1967-02-15 Kenneth Richardson Morton Improvements in or relating to incinerators
US4196713A (en) * 1978-03-06 1980-04-08 Atlanta Stove Works, Inc. Fuel burning heater

Also Published As

Publication number Publication date
NO146444B (en) 1982-06-21
FI65666B (en) 1984-02-29
IT8121659A0 (en) 1981-05-12
LU83344A1 (en) 1981-07-24
ES8204131A1 (en) 1982-04-01
JPS576205A (en) 1982-01-13
BE888739A (en) 1981-08-28
FI65666C (en) 1984-06-11
PT73025A (en) 1981-06-01
IE811065L (en) 1981-11-13
GB2081888A (en) 1982-02-24
FI811442L (en) 1981-11-14
DE3117290C2 (en) 1990-10-31
IE51048B1 (en) 1986-09-17
GB2081888B (en) 1985-01-30
ES502191A0 (en) 1982-04-01
FR2482702B1 (en) 1988-01-29
CH654645A5 (en) 1986-02-28
NO146444C (en) 1985-10-08
SE8102975L (en) 1981-11-14
FR2482702A1 (en) 1981-11-20
IT1137009B (en) 1986-09-03
SE446904B (en) 1986-10-13
NL8102249A (en) 1981-12-01
PT73025B (en) 1982-06-17
DK210481A (en) 1981-11-14
NO801421L (en) 1981-11-16
DE3117290A1 (en) 1982-03-25

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