WO1987000909A1 - Procede et appareil brulant un combustible solide - Google Patents

Procede et appareil brulant un combustible solide Download PDF

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Publication number
WO1987000909A1
WO1987000909A1 PCT/GB1986/000465 GB8600465W WO8700909A1 WO 1987000909 A1 WO1987000909 A1 WO 1987000909A1 GB 8600465 W GB8600465 W GB 8600465W WO 8700909 A1 WO8700909 A1 WO 8700909A1
Authority
WO
WIPO (PCT)
Prior art keywords
combustion zone
combustion
primary
zone
air inlet
Prior art date
Application number
PCT/GB1986/000465
Other languages
English (en)
Inventor
John Edward Michael Barnatt Millns
John Roger Fillingham
Original Assignee
Nova Stove (1986) Limited
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 Nova Stove (1986) Limited filed Critical Nova Stove (1986) Limited
Publication of WO1987000909A1 publication Critical patent/WO1987000909A1/fr

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23M—CASINGS, LININGS, WALLS OR DOORS SPECIALLY ADAPTED FOR COMBUSTION CHAMBERS, e.g. FIREBRIDGES; DEVICES FOR DEFLECTING AIR, FLAMES OR COMBUSTION PRODUCTS IN COMBUSTION CHAMBERS; SAFETY ARRANGEMENTS SPECIALLY ADAPTED FOR COMBUSTION APPARATUS; DETAILS OF COMBUSTION CHAMBERS, NOT OTHERWISE PROVIDED FOR
    • F23M9/00—Baffles or deflectors for air or combustion products; Flame shields
    • F23M9/06—Baffles or deflectors for air or combustion products; Flame shields in fire-boxes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23B—METHODS OR APPARATUS FOR COMBUSTION USING ONLY SOLID FUEL
    • F23B5/00—Combustion apparatus with arrangements for burning uncombusted material from primary combustion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24B—DOMESTIC STOVES OR RANGES FOR SOLID FUELS; IMPLEMENTS FOR USE IN CONNECTION WITH STOVES OR RANGES
    • F24B1/00—Stoves or ranges
    • F24B1/02—Closed stoves
    • F24B1/026—Closed stoves with several combustion zones

Definitions

  • This invention relates to a method and apparatus for burning solid fuel.
  • solid fuel' as used in this specification there is meant fuels such as wood, coal, straw, lignite, peat and the like, and mixtures of such solid fue Is .
  • An object of the present invention is to provide apparatus for burning solid fuel, and a method thereof offering improvements in relation to one or more of the matters discussed herein. Certain aspects of the present invention are applicable not only to domestic heating apparatus, but also more widely.
  • the embodiment described below provides for improved secondary combustion during the first phase of combustion of a solid fuel, and enables the secondary combustion to be commenced at a particularly early stage, moreover means is provided for adapting existing domestic and other stoves and furnaces for these purposes .
  • the invention also pro ides a method and apparatus for burning solid fuel not limited by each feature of any claim herein, but comprising any novel feature or ' novel combination of features disclosed in this app Ii cati on .
  • the drawing apparatus 10 for burning solid fuel comprises a lower portion 12 providing a primary combustion zone 14, and an upper portion 16 providing a secondary combustion zone 18.
  • Solid fuel 20 is burnt in lower portion 12 of the apparatus.
  • Combustion products including volatile fuel constituents, hydrocarbons and the like pass upwards through combustion zone 18 where secondary combustion takes place. Heat is extracted by heat exchangers 22, 24,
  • zone 18 is shown approximately by dotted lines in the drawing .
  • Lower portion 12 of the apparatus comprises a body portion 32 supporting a fire grate 34 including riddling means for agitating the fire bed 20, an ash pan 36, and a thermostatically controlled primary air inlet 38.
  • Doors 40 are hinge-mounted and provided with glass windows 42 and a, regionally ad ustable secondary - plate ' J 7 air inlet 44.
  • a finned 46 supports the front
  • ATV entering via inlet 44 passes upwardly over the heated plate and thence past the glass 42 of the doors 40 and into secondary combustion zone 18.
  • the water-filled heat exchangers 22 and 24 extend along three sides of the fire bed 20 and are hydraulically interconnected with each other and with the water jackets 26, 28, which are themselves interconnected by a connection duct 48.
  • Upper portion 16 of apparatus 10 comprises lower and upper refractory members 50 and 52 respectively forming part of secondary combustion zone 18.
  • the refractory members 50 and 52 are generally of plate or baffle-like form and located directly above primary combustion zone " 14. They are mounted in vertically spaced positions one above the other and extend across the full width of the primary and secondary combustion zones. The arrangement is such that the combustion products from the primary combustion zone pass slowly through the secondary combustion zone, over the extensive surface areas of the refractory members, and these cause the volatile and combustible constituents of the primary combustion to undergo secondary combustion in zone 18, afte which heat is extracted by the heat exchangers 26, 28 and 48.
  • Lower refractory member 50 is in the form of a baffle formed from ceramic fibre board.
  • T is material is currently available in the UK under the name Morganite ceramic fibre board. Morganite is a trade mark.
  • Baffle 50 is mounted on supports 54 and 56, so as to be removable for servicing purposes. It has a protec lower steel plate 57 and/or a-n open-work jacket of stainless steel mesh material to -render it more durable.
  • Baffle 52 is likewise formed of ceramic fibre board and is of greater thickness than board 50 and formed with vertical openings 58 whereby the gases passing therethrough are caused to swirl and mi .
  • ceramic fibre board is presently the preferred material for the refractory members 50 and 52, other materials may be used if desired, and better materials may emerge in the future.
  • the preferred properties of the refractory members include having a low thermal capacity and a low thermal conductivity.
  • Alternative possibly suitable materials include fibreglass (but this may soften and distort), silica and asbestos. Certain fire clay materials may also be suitable. The need for both a low thermal capacity and from conductivity arises , the need for the refractory member to achieve a high surface temperture from a limited quantity of heat in a short time.
  • conventional refractory ceramic brick material has a relatively high specific heat and is therefore not a preferred material although it maybe usable in situations where a plentiful supply of hea.t is available.
  • the requirement for low thermal capacity is of less significance.
  • a simple test for suitability of a material for the purpose comprises heating the surface of a sample of the material with a small hand held gas torch. It is found that in the case of ceramic fibre board, such a torch produces a red hot glow in 5 seconds or less, and such a material is to be preferred. Periods of up to 10 and 20 seconds to produce such a glow may be acceptable for certain types of combustion appratus. This test serves also to test for low thermal conductivity.
  • Ceramic fibre board of thickness approximately one centimetre can glow red hot on one side while being merely 'hand hot' on the other.
  • the conductivity of the refractory material need not necessarily be as low as this, but must certainly be significantly less than that of a metal. Materials equivalent to ceramic fibre board may be identified thus.
  • the important function of the refractory members 50 and 52 is that they achieve, during the first phase of combustion, a temperature ithin zone 18 suff cient to produce spontaneous combustion of the combustion products, volatiles, hydrocarbons etc from the primary combustion zone.
  • the temperatures needed for this purpose are as low as 420 C to 460 C for acetylene, and 650 C to 750 C for methane and 644 C to 658 C for carbon monoxide and approxi ately 550 C for the remainder of the combustion products.
  • a tteemmppeerraattuurree ooff 550000 C or above will usually be sufficient for most purposes.
  • Heat exchangers 26 and 28 are of generally plate ⁇ like form being disposed generally horizontally, the former being mounted as a forward extension of refractory member 52. Gases passing through holes 58 in the latter are intercepted by heat exchanger 28 and pass around the side and forward edges of the latter.
  • a series of fins 60 are mounted on the upper surface of heat exchanger 28 and lie in planes extending from front to rear of apparatus 10. Mounted above ' the fins is a top plate 62 having a central opening 64 through which the cooled gases pass to flue 30.
  • a butterfly-type restrictor 66 operable by a handle 68 is provided to regulate the updraught applied to apparatus 10 by the chimney.
  • Heat exchangers 22, 24, 26 and 28 are connected through an inlet 70 and an outlet 72 to a hot water consuming system such as a domestic central heating system.
  • combustion products including unburnt volati les and gases pass upwards through primary combustion zone 14 to refractory baffle 50.
  • the latter causes the combustion products to circulate within combustion zone 14 thereby promoting a ra id rise in te perature and intimate mixing of the gases.
  • the surface temperature of the refractory members 50 and 52 rises much more rapidly than those of the surrounding structures and soon reach the level of 420 C to 460 C at which any acetylene present will ignite.
  • 500° C to 550 C a number of the other combustion products will ignite and then the surface temperatures of the baffles will soar, causing more of the combustible components entering the secondary combustion zone 18 to igni te.
  • the secondary combustion air entering through inlet 44 reaches combustion zone 18 in a relatively hot condition and is mixed with the combustion products there. Its relatively high temperature ensures that the gas mixture is not chilled, which in prior art apparatus has tended to damp down and sometimes prevent secondary combustion.
  • the relatively tortuous path which the gases adopt as they pass around the refractory members ensures inti mate mixing and intimate surface contact with the refractory members whereby combustion is promoted.
  • Control of the output of the apparatus 10 is by means of the thermostatic control of primary air inlets 38.
  • the control may be based upon water temperature in the heat exchangers. It is particularly to be noted that the secondary air supply is not throttled when the primary air supply is. In this way, although the fire bed combustion may be damped down by reduced air supply, the combustion in the secondary combustion zone is permitted to continue without hindrance, whereby more complete combustion is ac ieved than with conventional arrangements in which the secondary air supply is also throttled .
  • the heating means for the secondary combustion zone may comprise surface heating means such as an electrical heating element mounted on the refractory materials themselves. However, it is preferred to provide external heating means to effect surface heating of the refractory materials, for example by means of a blast of hot air or a flame. External electrical heating means could be provided to produce a hot air supply at, for example, 750° C to 1250° C. Such a hot air blast could be introduced into the apparatus in secondary combustion zone 18 so as to impinge on the surfaces of the refractory members, thereby raising them to the above -mentioned temperatures for producing spontaneous combustion of the primary combustion products.
  • a supply of preheated air in the above manner may replace the secondary air supply for normal operation of the apparatus.
  • a temperature probe may be provided to monitor the surface temperature of the refractory materials and a control system may then control the heat supply to the air blast or current .
  • Adoption of an external heat source for preheating the refractory materials by means of an air or gas current has the advantage that this heat source can be located outside the harsh env ronment of the secondary combustion zone, and thereby its working life extended.
  • the advantages of the present embodi ent are not limited to the general configuration shown in the accompanying drawing and the concept of preheating the secondary combustion zone is applicable to any form of solid fuel combustion appa ratus .
  • the secondary combustion zone need not be located directly above the pri ary combustion zone. It could for example be offset to one side or otherwise displaced, but connected to the primary combustion zone to receive combustion products rising therefrom.
  • the invention is appl cable to any form of solid fuel combustion appliance, and certain aspects are applicable to non-domestic combustion appliances,
  • the refractory members of the above embodiment may be retro-fitted to existing heating appliances in some cases so as to establ sh the possibility of secondary combustion.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Air Supply (AREA)

Abstract

Le procédé et l'appareil brûlant un combustible solide permettent la combustion secondaire de produits de combustion volatils ce qui a pour conséquence de réduire les émanations de fumée et d'augmenter le rendement. La combustion secondaire s'effectue au moyen de déflecteurs réfractaires en plaque de fibre céramique montés au-dessus de la zone de combustion primaire. Une alimentation préchauffée d'air secondaire est amenée dans la zone de combustion secondaire. L'invention prévoit une source de chaleur indépendante pour les organes déflecteurs réfractaires. Cette source de chaleur peut être une source externe d'air de combustion secondaire chauffé.
PCT/GB1986/000465 1985-08-03 1986-08-04 Procede et appareil brulant un combustible solide WO1987000909A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB858519577A GB8519577D0 (en) 1985-08-03 1985-08-03 Heating apparatus
GB8519577 1985-08-03

Publications (1)

Publication Number Publication Date
WO1987000909A1 true WO1987000909A1 (fr) 1987-02-12

Family

ID=10583298

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1986/000465 WO1987000909A1 (fr) 1985-08-03 1986-08-04 Procede et appareil brulant un combustible solide

Country Status (3)

Country Link
AU (1) AU6198186A (fr)
GB (1) GB8519577D0 (fr)
WO (1) WO1987000909A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995004242A1 (fr) * 1993-07-30 1995-02-09 System Teeg Ab Dispositif de combustion de combustibles solides
WO2010070275A2 (fr) * 2008-12-15 2010-06-24 Graham Thornhill Four de brûlage de combustible
JP2014137168A (ja) * 2013-01-16 2014-07-28 Okamoto Co Ltd 薪ストーブ

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3310009A (en) * 1964-03-05 1967-03-21 John H Jacobs Incinerator for refuse material
US3543700A (en) * 1969-07-07 1970-12-01 Environmental Control Products Air purifying incinerator apparatus
EP0025424A1 (fr) * 1979-09-10 1981-03-18 Aksjeselskapet Jotul Poêle
FR2482702A1 (fr) * 1980-05-13 1981-11-20 Joetul As Poele a combustible solide comportant deux chambres de combustion isolees thermiquement
FR2548759A1 (fr) * 1983-07-04 1985-01-11 Greneu Robert Accessoire permettant d'obtenir la quasi-totalite de la combustion des combustibles dans les appareils de chauffage et production d'eau chaude ou autre
DE3340107A1 (de) * 1983-11-05 1985-05-15 Franz X. 6200 Wiesbaden Wittek Verfahren zum betreiben von heizkesseln mit verduesbaren brennstoffen und heizkessel zur durchfuehrung des verfahrens

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3310009A (en) * 1964-03-05 1967-03-21 John H Jacobs Incinerator for refuse material
US3543700A (en) * 1969-07-07 1970-12-01 Environmental Control Products Air purifying incinerator apparatus
EP0025424A1 (fr) * 1979-09-10 1981-03-18 Aksjeselskapet Jotul Poêle
FR2482702A1 (fr) * 1980-05-13 1981-11-20 Joetul As Poele a combustible solide comportant deux chambres de combustion isolees thermiquement
FR2548759A1 (fr) * 1983-07-04 1985-01-11 Greneu Robert Accessoire permettant d'obtenir la quasi-totalite de la combustion des combustibles dans les appareils de chauffage et production d'eau chaude ou autre
DE3340107A1 (de) * 1983-11-05 1985-05-15 Franz X. 6200 Wiesbaden Wittek Verfahren zum betreiben von heizkesseln mit verduesbaren brennstoffen und heizkessel zur durchfuehrung des verfahrens

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995004242A1 (fr) * 1993-07-30 1995-02-09 System Teeg Ab Dispositif de combustion de combustibles solides
WO2010070275A2 (fr) * 2008-12-15 2010-06-24 Graham Thornhill Four de brûlage de combustible
WO2010070275A3 (fr) * 2008-12-15 2011-01-06 Graham Thornhill Four de brûlage de combustible
GB2478889A (en) * 2008-12-15 2011-09-21 Graham Thornhill A fuel-burning stove
GB2478889B (en) * 2008-12-15 2013-09-25 Graham Thornhill A fuel-burning stove
JP2014137168A (ja) * 2013-01-16 2014-07-28 Okamoto Co Ltd 薪ストーブ

Also Published As

Publication number Publication date
AU6198186A (en) 1987-03-05
GB8519577D0 (en) 1985-09-11

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