Burner for a solid fuel-fired steel construction boiler

Description

[0001] This invention relates to a burner of a solid fuel-fired steel construction boiler.

[0002] Known and available on the market are solid fuel-fired steel construction boilers for civil heating applications which comprise a space portion of vertically elongate shape, delimited by longitudinal side walls, a bottom and a cover lined with an interspace containing water to be heated, as well as front and rear faces also provided, at least partially, with a similar interspace.

[0003] Said space portion is subdivided into an upper zone and a lower zone, and a burner is provided at the sub-division between the two zones; the upper zone is intended for containing the fuel which is loaded from a door provided in the front face, whilst in the lower zone, there occurs the development of the flame issuing from said burner and conveyance of the flue gases toward a smoke box located at the rear face and provided with a connection to the chimney. Located on the front face is a combustion air metering unit which comprises an electric fan controlled by an automatic regulating circuit, and a distribution chamber whence primary air flows out toward the top of the upper zone of the boiler, whilst secondary air flows out at the burner to complete the combustion. Such a boiler is disclosed in the FR-A-1016208.

[0004] The boiler just described has considerable virtues and advantages; however, the burners proposed up to the present time have failed to provide fully satisfactory characteristics, but accumulated work experience has allowed the development of an improved burner which the present patent is directed to protect.

[0005] It is the aim of this invention to provide an improved burner for solid fuel-fired steel construction boilers, wherein no state of dangerous deformations is encountered in operation, and which can provide optimum mixing of the products of combustion promoted by the primary air with the secondary air.

[0006] Within the above aim, it is an object of the invention to provide a burner whereby the combustion temperature can be pushed to very high values so as to decrease the excess air and further improve the performance level.

[0007] Another object of the invention is to provide a burner which has those parts which are most liable to wear out of low cost and readily removable, thereby the damage is limited to a minimum with the replacement thereof at the end of a useful life cycle.

[0008] The proposed aim, and the mentioned objects, are achieved by an improved burner for a solid fuel-fired steel construction boiler, according to the invention, said boiler comprising a space portion lined with an interspace containing water to be heated, subdivided into an upper fuel-containing zone and lower zone wherein the development of the flame and conveyance of the flue gases generated from a burner situated at the subdivision between said upper and lower zones take place, and provided at the front face with a combustion air metering unit which comprises a distribution chamber supplied from an electric fan whence primary airflows outtoward the top of the upper zone whilst secondary air flows out at the burner, characterized in that it comprises a refractory stone block laid in a substantially horizontal plane to delimit the upper and lower zones of the boiler space portion, provided on the top face with a housing which has the bottom formed at a substantially center location with a hole adapted to put into communication said upper and lower zones of the boiler space portion, and adapted to contain, resting on the bottom at the periphery of the hole, at least one body formed from a refractory material having at the space portion directly overlying the hole means of holding the overlying embers, the housing bottom and surface of said body intended to rest on said bottom being configured to define, on coming into contact, a ducting opening in correspondence with the hole and communicating with the air distribution chamber for conveying secondary air.

[0009] Further features and advantages will be apparent from the description of two preferred but not exclusive embodiments of the invention, as shown by way of illustration and not of limitation in the accompanying drawings, where:

Figure 1 is a partly exploded view of a first embodiment of the invention;

Figure 2 is a fragmentary sectional view of a boiler incorporating a burner of the type shown in Figure 1, taken on the plane II-II of Figure 3;

Figure 3 is a section taken on the plane III-III of Figure 2;

Figure 4 is a partly exploded view of a first variation of the invention; and

Figure 5 is a detail view of a fire bar provided in the variation of Figure 4.

[0010] With reference to the cited Figures 1, 2, 3, generally indicated at 1 is the burner, which is supported on shelves 2 extending from the walls 3 of the boiler space portion lines with the interspace or jacket of water 4to be heated so as to delimit the upper zone 5a of said space portion containing the fuel, which in the figure is represented by firewood pieces but could indifferently be coal or any other solid fuel, separating it from the lower portion 5b wherein the flame development and conveyance of the flue gases toward a smoke box, not shown in the figure and located at the rear face, take place; provided in a known manner at the front face is a combustion air metering unit which comprises the distribution chamber 6 supplied from the electric fan 7, whence primary air flows out toward the top of the upper zone 5a whilst secondary air is delivered to the burner 1 as explained hereinafter.

[0011] The burner 1 comprises the refractory stone block 8, with a refractory material 8a filling at the edges thereof and which has at the top face the housing 9, at the bottom whereof there is provided the elongate hole 10 which communicates the upper zone 5a with the lower zone 5b of the boiler space portion.

[0012] Resting on the bottom of the housing 9, at the edges of the hole 10, are the fire bars formed from a refractory material 11 and 12 which have on the face confronting said hole a plurality of facing serrations: clearly visible in Figure 1 are those of the fire bar 11, respectively indicated at 13, 14, 15, 16, and owing to the particular choice of the sectional view taken on the plane III-III, also in Fig. 3, a serration indicated at 15 is visible in elevation; identical and, as mentioned, confronting them, are the serrations of the fire bar 12, one of which, shown in side elevation, is visible in Figure 3 and is indicated at 17.

[0013] As is apparent from the drawing figures, the serrations of the fire bars protrude, without coming into mutual contact, into the space portion overlying the hole 10 with surfaces which, extending substantially from the edges of said hole, have an inclined lower portion as at 13a and a substantially vertical upper portion as at 13b, thereby a means of holding the overlying embers is provided.

[0014] At the face resting on the bottom of the housing the fire bars 11 and 12 have a series of throughgoing transverse slots: clearly visible in Figures 1 and 2 are those of the fire bar 12, respectively indicated at 18, 19, 20, 21, 22, and the slot 20 is also visible in the sectional view of Figure 3; as regards the fire bar 11, visible in Figure 1 are the outlets of the slots 23, 24, 25, 26, 27, and the slot 25 is fully visible in the sectional view of Figure 3.

[0015] The aforesaid slots in the fire bar 12 are in communication with the longitudinal recess 28, and those in the fire bar 11 with the like recess 29, said recesses 28 and 29 are located to correspond with the holes 28a, 29a, respectively, formed in the block 8 facing holes such as 6a in communication with the distribution chamber for the combustion air 6.

[0016] In this way, the resting of the fire bars 11 and 12 on the bottom of the housing 9 results in the formation of a ducting at the longitudinal recesses and cross slots wherethrough secondary air, entering the holes 28a, 29a, reaches from the distribution chamber 6 the space portion directly overlying the hole 10.

[0017] Thus, in the space portion defined by the serrations of the fire bars 11 and 12 and the hole 10 there is defined a form of pre-chamber where the gas produced by the combustion of primary air with the fuel overlying the burner, still loaded with combustible substances, enter from above and combine with the secondary air which is advantageously pre-heated, to provide a complete combustion which, together with the possibililty of pushing much higher the flame temperature thanks to the contribution afforded by the very refractory material which has been adopted for the burner construction, ensures optimum performance.

[0018] In addition to this feature, it should be noted that the burner is configured so as not to develop dangerous deformations, and that those parts of it which are more liable to wear out, i.e. those in direct contact with the embers, have been formed of fire bars which are replaceable, with a very simple operation that any user can carry out, and at very low cost.

[0019] With reference to Figures 4 and 5 a variation of the burner will now be described; this variation again includes the refractory stone block 8 with housing 9 provided at the bottom with the hole 10 adapted to put in communication the upper and lower zones of the boiler space portion, and at the edges of the hole 10 there are laid onto the flat bottom of the housing the two fire bars 30 and 31 of refractory material which have, similarly to what has been described for the fire bars 11 and 12, the surface intended to rest onto the bottom formed with throughgoing cross slots 32, 33, 34, 35, 36 for the fire bar 30, in communication with longitudinal recesses such as 37 intended for arranging themselves at the holes 28a, 29a formed in the block 8 for admitting secondary air at the burner.

[0020] The embers holding means overlying the hole 10 with which the fire bars 30 and 31 are equipped in this variation comprises a metal grid which is constructed in several parts to avoid dangerous deformations, and is accordingly formed by the round cross-section rods 38 and 39, intended to arrange themselves in corresponding alignment at the axis of the hole 10 following resting of the cross-pieces 38a, 38b and 39a, 39b with which they are provided in the cutouts 40, 41, 42, 43 of the fire bar 30 and confronting cutouts 44, 45, 46, 47 of the fire bar 31.

[0021] The invention described herein is susceptible to many other modifications and variations: thus, as an example, the fire bars inserted into the housing provided in the refractory stone block may be replaced with a monolithic body, or a series of modular elements, and the secondary air conveying ducting may be formed, at least in part, on the bottom of said housing.

Claims

1. A burner of a solid fuel-fired steel construction boiler, said boiler comprising a space portion lined with an interspace or jacket containing water (4) to be heated, subdivided into an upper fuel-containing zone (5a) and a lower zone (5b) where the flame development and conveyance of the flue gases which are generated in a burner (1) located at the separation between said upper and lower zones (5a, 5b) take place, and provided at the front face with a combustion air metering unit which comprises a distribution chamber (6) supplied from an electric fan (7) whence primary air flows out toward the top of the upper zone (5a) whilst secondary air flows out at the burner (1), characterized in that it comprises a refractory stone block (8) laid in a substantially horizontal plane so as to delimit the upper zone (5a) and lower zone (5b) of the boiler space portion, provided on the top face with a housing (9) which has the bottom formed at a substantially center location with a hole (10) adapted to put into communication said upper and lower zones (5a, 5b) of the boiler space portion, and is adapted to contain, resting on the bottom at the periphery of the hole (10), at least one body (11, 12, 30, 31) formed from a refractory material provided at the space portion directly overlying the hole with a means of holding the overlying embers (13-16, 38-39b), the housing (9) bottom and the surface of said body (11, 12, 30, 31) intended to rest on said bottom being configured to define, when brought into contact, a ducting (28,29) opening at the hole (10) and communicating with the air distribution chamber (6) for conveying secondary air.

2. A burner according to Claim 1, characterized in the fact that the refractory stone block (8) has a substantially parallelepipedal shape and is supported on shelves (2) extending from walls (3) and faces of the boiler space portion.

3. A burner according to one or more of the preceding claims, characterized by the presence of a filling of a refractory material (8a) between the refractory stone block (8) and at least the walls (3) of the boiler space portion.

4. A burner according to one or more of the preceding claims, characterized in that the housing (9) provided in the refractory stone block (8) is adapted to contain two fire bars (11, 12, 30, 31) formed from a refractory material and resting on the flat bottom at the edges of an elongate hole (10), provided with a means (13-16) of holding the overlying embers consisting of confronting serrations (13-16) which.protrude monolithically therefrom, without coming into contact, in the space portion directly overlying said hole (10), extending substantially from the edges of the hole (10) with a surface which has an inclined lower portion (13a) and a substantially vertical upper portion (13b), each of said fire bars (11, 12, 30, 31) being further provided, at the face resting on the housing bottom, with throughgoing cross slots (18-27), communicating with a longitudinal recess (28, 29) located at a hole (28a, 29a) formed in the refractory stone block (8) communicating with the combustion air distribution chamber (6) for admission of secondary air.

5. A burner according to one or more of the preceding claims, characterized in that the housing (9) provided in the refractory stone block (8) is adapted to contain two fire bars (11, 12, 30, 31) formed from a refractory material resting on the flat bottom at the edges of an elongate hole (10), provided with a means of holding the overlying embers consisting of a metal grid (38-39b) adapted to rest in special cutouts (40-47) formed at the edge adjacent to the hole of the top surface thereof, each of said fire bars (30, 31) being also provided, at the face resting on the bottom of the housing (9), with throughgoing cross slots (32-36) communicating with a longitudinal recess (37) located at a hole (28a, 29a) formed in the refractory stone block (8) communicating with the combustion air distribution chamber (6) for admission of secondary air.

6. A burner according to claim 5, characterized in that the metal grid comprises a plurality of a round cross-section rods (38, 39) adapted to arrange themselves aligned at the longitudinal axis of the underlying hole (10), each of which is provided with at least two crosspieces (38a, 38b, 39a, 39b) resting in the fire bar cutouts (40-47).

Ansprüche

1. Brenner für einen mit festem Brennstoff betriebenen Heizkessel aus Stahl, mit einem Kesselraum, der mit einem das zu erwärmende Wasser (4) enthaltenden Zwischenraum oder Mantel umgehüllt und in eine obere, den Brennstoff enthaltende Zone (5a) und eine untere Zone (5b) unterteilt ist, in welcher die Entwicklung der Flamme und der Transport der Rauchgase stattfinden, welche von einem Brenner (1) erzeugt werden, der im Trennbereich zwischen der oberen und der unteren Zone (5a, 5b) angeordnet und an der Stirnseite mit einer Verbrennungsluft-Dosiereinheit versehen ist, die aus einer Verteilerkammer (6) besteht, welche von einem elektrischen Gebläse (7) gespeist wird, von wo aus Primärluft gegen den oberen Bereich der oberen Zone (5a) ausströmt, wogegen Sekundärluft beim Brenner (1) ausströmt, gekennzeichnet durch einen feuerfesten Steinblock (8), der in einer im wesentlichen horizontalen Ebene verlegt ist, um auf diese Weise die obere Zone (5a) und die untere Zone (5b) des Heizkesselraumes zu begrenzen, und an der oberen Fläche mit einem Gehäuse (9) versehen ist, in dessen Boden im wesentlichen im Bereich der Mitte desselben ein Loch (10) ausgebildet ist, durch welches die obere und die untere Zone (5a, 5b) des Heizkesselrau- , mes miteinander verbunden werden, und welches befähigt ist, indem es auf dem Boden an der Peripherie des Loches (10) aufsitzt, wenigstens einen aus feuerfestem Material gefertigten Körper (11, 12, 30, 31) aufzunehmen, der im Bereich des Raumabschnitts, der direkt oberhalb des Loches liegt, mit einer Einrichtung zur Halterung der darüberliegenden Glut (13-16, 38-39b) versehen ist, wobei der Boden des Gehäuses (9) und die Oberfläche des Körpers (11, 12, 30, 31), die zur Auflage auf dem Boden bestimmt ist, derart geformt sind, daß sie, wenn sie miteinander in Berührung gebracht werden, einen Kanal (28, 29) begrenzen, der beim Loch (10) ausmündet und mit der Luftverteilerkammer (6) zum Zwecke des Transportes der Sekundärluft in Verbindung steht.

2. Brenner nach Anspruch 1, dadurch gekennzeichnet, daß der feuerfeste Steinblock (8) eine im wesentlichen parallelepipedische Form besitzt und auf Konsolen (2) aufsitzt, die sich von den Wänden (3) und Flächen des Heizkesselraumes aus erstrecken.

3. Brenner nach einem oder mehreren der vorhergehenden Ansprüche, gekennzeichnet durch die Gegenwart einer Füllung aus feuerfestem Material (8a) zwischen dem feuerfesten Steinblock (8) und wenigstens den Wänden (3) des Heizkesselraumes.

4. Brenner nach einem oder mehreren der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß das im feuerfesten Steinblock (8) vorgesehene Gehäuse (9) zwei Roststäbe (11, 12, 30, 31) aufnehmen kann, die aus feuerfestem Material bestehen und auf dem flachen Boden an den Rändern eines langestreckten Loches (10) aufsitzen und mit einer Halterungsvorrichtung (13-16) für die daraufliegende Glut versehen sind, welche aus gegenüberliegenden Rippungen (13-16) besteht, die monolithisch von den Roststäben, ohne in Berührung zu kommen, in den direkt über dem Loch (10) befindlichen Raum hineinragen und sich von den Rändern des Loches (10) weg mit einer Oberfläche erstrecken, die einen schrägverlaufenden unteren Abschnitt (13a) und einem im wesentlichen vertikal verlaufenden oberen Abschnitt (13b) besitzt, wobei jeder der Roststäbe (11, 12, 30, 31) weiters an der auf dem Gehäuseboden aufsitzenden Fläche mit durchgehenden Querschlitzen (18-27) versehen ist, die mit einer Längsausnehmung (28, 29) in Verbindung stehen, die bei einem im feuerfesten Steinblock (8) ausgebildeten Loch (28a, 29a) liegen, welches zwecks Zufuhr der Sekundärluft mit der Verbrennungs-Verteilerkammer (6) in Verbindung steht.

5. Brenner nach einem oder mehreren der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß das im feuerfesten Steinblock (8) vorgesehene Gehäuse (9) zur Aufnahme von zwei aus feuerfestem Material bestehenden Roststäben (11,12,30,31) ausgebildet ist, die auf dem flachen Boden an den Rändern eines langgestreckten Loches (10) aufsitzen und mit einer Halterungsvorrichtung für die daraufliegende Glut versehen sind, welche aus einem Metallgitter (38-39b) besteht, der in besonderen Ausnehmungen (40-47) liegt, die am Rand neben der oberen Fläche des Loches ausgebildet sind, wobei jeder der Roststäbe (30, 31) weiters an der auf dem Boden des Gehäuses (9) aufsitzenden Fläche mit durchgehenden Querschlitzen (32-36) versehen ist, die mit einer Längsausnehmung (37) in Verbindung stehen, welche sich bei einem Loch (28a, 29a) befindet, das im feuerfesten Steinblock (8) ausgebildet ist und zwecks Zufuhr der Sekundärluft mit der Verbrennungsluft-Verteilerkammer (6) in Verbindung steht.

6. Brenner nach Anspruch 5, dadurch gekennzeichnet, daß der Metallgitter (38, 39) aus einer Vielzahl von Stäben (38, 39) mit rundem Querschnitt besteht, die derart vorgesehen sind, daß sie auf der Längsachse des darunterliegenden Loches (10) fluchtend zu liegen kommen, wobei jeder derselben mit wenigstens zwei Querstücken (38a, 38b, 39a, 39b) versehen ist, die in die Ausnehmungen (40-47) in den Roststäben einrasten.

Revendications

1. Brûleur de chaudière en acier à combustible solide, ladite chaudière comportant un espace garni par un doublage ou une chemise contenant de l'eau (4) à chauffer, subdivisé en une zone supérieure (5a) contenant le combustible et une zone inférieure (5b) où se produisent la formation des flammes et l'écoulement des gaz de combustion produits dans un brûleur (1) situé au niveau de la séparation entre les zones supérieure et inférieure (5a, 5b), et pourvu sur sa face antérieure d'un dispositif de dosage d'air de combustion qui comprend une chambre de distribution (6) alimentée depuis un ventilateur électrique (7) d'où de l'air primaire sort vers le haut de la zone supérieure (5a) tandis que de l'air secondaire sort dans le brûleur (1 ), caractérisé en ce qu'il comporte un bloc (8) de maçonnerie réfractaire disposé dans un plan sensiblement horizontal de façon à délimiter la zone supérieure (5a) et la zone inférieure (5b) de l'espace de la chaudière, pourvu sur sa face supérieure d'un logement (9) dont le fond possède sensiblement en son centre un trou (10) conçu pour mettre en communication lesdites zones supérieure et inférieure (5a, 5b) de l'espace de la chaudière, et est conçu pour contenir, reposant sur te fond à la périphérie du trou (10), au moins un massif (11, 12, 30, 31) en matière réfractaire, pourvu dans l'espace situé juste au-dessus du trou d'un moyen de retenue des braises sus-jacentes (13-16, 38-39b), le fond du logement (9) et la surface du massif (11, 12, 30, 31) destinée à reposer sur ledit fond ayant une configuration visant à définir, quand on les met en contact, un conduit (28, 29) débouchant dans le trou (10) et communiquant avec la chambre (6) de distribution d'air pour faire circuler t'air secondaire.

2. Brûleur selon la revendication 1, caractérisé en ce que le bloc (8) de maçonnerie réfractaire a une forme sensiblement parallélépipédique et est soutenu par des tablettes (2) s'étendant depuis les parois (3) et les faces de l'espace de la chaudière.

3. Brûleur selon une ou plusieurs des revendications précédentes, caractérisé par la présence d'un remplissage de matière réfractaire (8a) entre le bloc (8) de maçonnerie réfractaire et au moins les parois (3) de l'espace de la chaudière.

4. Brûleur selon une ou plusieurs des revendications précédentes, caractérisé en ce que le logement (9) présent dans le bloc (8) de maçonnerie réfractaire est conçu pour contenir deux barres (11, 12, 30, 31) de foyer en matière réfractaire reposant sur leur fond plat sur les bords d'un trou allongé (10), pourvues d'un moyen (13-16) de retenue des braises sus-jacentes constitué de dentelures (13-16) se faisant front qui dépassent d'une seule pièce de celui-ci, sans venir en contact, dans l'espace situé juste au-dessus du trou (10), s'étendant sensiblement depuis les bords du trou (10) avec une surface qui a une partie inférieure inclinée (13a) et une partie supérieure sensiblement verticale (13b), chacune des barres (11, 12, 30,31) de foyer étant en outre pourvue, sur la face reposant sur le fond du logement, d'encoches transversales (18-27) traversant d'un bout à l'autre, communiquant avec un évidement longitudinal (28,29) situé au niveau d'un trou (28a, 29a) ménagé dans le bloc (8) de maçonnerie réfractaire communiquant avec la chambre (6) de distribution d'air de combustion pour l'admission de l'air secondaire.

5. Brûleur selon une ou plusieurs des revendications précédentes, caractérisé en ce que le logement (9) réalisé dans le bloc (8) de maçonnerie réfractaire est conçu pour contenir deux barres (11, 12, 30, 31) de foyer en matière réfractaire reposant sur leur fond plat sur les bords d'un trou allongé (10), pourvues d'un moyen de retenue des braises sus-jacentes constitué d'une grille métallique (38-39b) conçu pour reposer dans des découpures spéciales (40-47) ménagées sur le bord contigu au trou de la surface supérieure de celles-ci, chacune desdites barres (30, 31) de foyer étant également pourvue, sur sa face reposant sur le fond du logement (9), d'encoches transversales (32-36) traversant d'un bout à l'autre communiquant avec un évidement longitudinal (37) situé au niveau d'un trou (28a, 29a) formé dans le bloc (8) de maçonnerie réfractaire communiquant avec la chambre (6) de distribution d'air de combustion pour l'admission de l'air secondaire.

6. Brûleur selon la revendication 5, caractérisé en ce que la grille métallique comprend une pluralité de barreaux (38, 39) à section circulaire conçus pour se trouver alignés selon l'axe longitudinal du trou (10) situé au-dessous, dont chacun est doté d'au moins deux traverses (38a, 38b, 39a, 39b) reposant dans les découpures (40-47) des barres de foyer.

Drawing