FR2506909A1 - Solid fuel central heating boiler - has water ducts to sides and above grate and specified pattern of further vertical water ducts - Google Patents

Abstract

The central heating boiler (1) comprises water spaces at two sides which are connected via water ducts (19,21,22) with passages for the combustion gas between them. Two ducts (21,22) are arranged to either side above the grate and form an upwardly converging central passage between them, whilst an inverted U-section duct (19) is arranged above the fire. To either side of this duct there is at least one vertical water duct (9,11,13;10,12,14) whilst a second vertical water duct (15,16) is arranged above either side of the duct (19) leaving passages above and below (58,59) it. A third vertical water duct (17,18) is placed inward of each duct (15,16) leaving a passage below it to a fly ash settling chamber whilst its upper end connects with the top (2) of the boiler via a baffle (25,26). FL.

Description

 The present invention relates to a heating boiler for the combustion of coal and, more particularly, for the combustion of what is called "fatty coal", this boiler being provided with incorporated separators of soot and dust, as well as d '' automatic cleaning elements, the smoke flues being installed so that despite the many changes of direction that must undergo the smoke gases, the boiler requires only a small draft, so that it becomes superfluous to provide an extractor.

The heating boiler according to the invention consists mainly of two end collectors connected to one another by water channels between which smoke flues are formed, this boiler being characterized in that two of the channels d are installed next to and above the burner, diverging from bottom to top; above these two water channels, there is an inverted U-shaped water channel; on either side of the water channel in
U, at least one vertical water channel is provided; next to the latter and at a well-determined distance, a second vertical water channel is provided which is placed above the relevant lateral edge of the U-shaped water channel and which, both at the top and at the bottom, leaves a passage; next to each of the second water channels mentioned last, there is a third vertical water channel which, at the top, forms a tight seal with the upper wall of the boiler and which, at the bottom, allows it to remain a passage to a dust precipitation chamber opening into the chimney.

In order to better emphasize the characteristics of the invention, a preferred embodiment will be described below, by way of example and without any limiting nature, with reference to the accompanying drawings in which
Figure 1 is a schematic cross section of a combustion boiler according to the invention;
Figure 2 is a section taken on the line II-II in Figure 1.

 The combustion boiler according to the invention mainly consists of a casing 1 which, at the top, is provided with a cover 2 provided with an outlet 3 in order to connect the boiler to a chimney, this casing being provided, below, a burner 4 to which coal is automatically conveyed via a line 5.

 The burner 5 also receives forced air circulation (in a manner not shown) in order to ensure efficient combustion.

 In the casing 1, at least at one end but, preferably at both ends, there is provided a door 6 through which one can access the burner 4 and the lower part of the boiler.

 In addition, the heating boiler consists of two end collectors 7 and 8 respectively into which open connections (not shown in the drawings) for the admission and evacuation of the circulating water.

 These end collectors 7 and 8 are connected to each other by means of vertical water channels 9-10, 11-12, 13-14, 15-16 and 17-18 respectively, by means of a inverted U-shaped water channel 19 comprising an inverted V-shaped body 20 above the burner, as well as by two water channels 21, 22 inclined near the burner and installed below the channel 19.

 It should be noted that the above-mentioned water channels are installed so that the channels 21, 22 diverge from bottom to top, the upper ends being situated higher than the lower ends of the flanges 23, 24 of the water channel ~ 19; the water channels 9 and 10 extend over the entire height of the boiler; the upper ends of the water channels 11, 13, 15, on the one hand, and 12, 14, 16, on the other hand, are arranged in steps, the lower ends of the water channels 11, 13, of on the one hand, and 12, 14, on the other hand, also being arranged in steps at a level lower than that of the lower ends of the above-mentioned flanges 23-24, while the lower ends of the water channels 15 and 16 terminate at above and at a well-determined distance from the water channel 19; the water channels 17 and 18 are installed so that their lower ends are located at a relatively large distance from the water channel 19, while their upper edges are placed against the cover 2 or against a seal 25 and 26 respectively.

 It should be noted that, in the accompanying drawings, the smoke flues 27, 28, 29 and 30 have a width equal to that of the smoke flues 31-32 at the location of the water channel 19, while, on the entire height of the water channels 15 and 16, the width of these channels 31-32 is slightly greater than that of the smoke flues 27 to 30, the total width of the smoke flues 27, 29, 31 being at least equal to the width of a smoke flue 33 or 34.

 The device described above is further completed by a cleaning mechanism which, in this case, consists of three rows of scraping elements or slats 35, 36 and 37 respectively which, in each row, are connected one to the other. the other by means of a bar 38, 39 and 40 respectively, these bars being able to be controlled each separately from the outside of the boiler, while, thanks to the back and forth movement of each row of scraper slats thus arranged, the upper wall of the boiler can be cleaned by scraping off the dust and soot.

 In the aforementioned slats 35, 36 and 37, cleaning elements 41, 42, 43, 44, 45 and 46 are further assembled respectively, on one side, as well as 47, 48, 49, 50, 51 and 52-, of the other side; to the cleaning elements 43, 44, 46 and 49, 50, 52, are fixed scraper slats 53 which can be moved above the upper wall of the water channel 19.

 The cleaning elements 41 to 52 can be formed by slats, bars, chains or the like, which are thus moved back and forth together with the aforementioned slats 35, 36 and 37, in order to clean , on the one hand, the smoke flues and, on the other hand, the upper wall of the water channel 19, this cleaning can be carried out while the boiler is in service.

 Thanks to the device thus produced, above the hearth, is formed a combustion compartment proper 54 having divergent side walls, thus creating a venturi effect having the consequence of causing, in this combustion compartment, a depression resulting from the dynamics. flame and flue gases blown upwards out of the coal burner 4.

 Behind each water channel 21-22, is formed a dust separation compartment 55-56 respectively in which the dust is separated from the gases, on the one hand, by expansion and reduction of speed of the gases and, on the other hand , by the cyclone effect, in particular the sudden change of direction of the gases at an angle of 1800.

 The smoke gases which continue to rise through the flues 27 to 32 are necessarily brought down into the flues 33-34 to exit into the so-called precipitation chamber 57.

 As a result of the widening of the smoke flues 31 and 32 at the location of the lower edges of the water channels 15 and 16, we obtain, at points 58 and 59, a venturi effect by which the gases flow or are sucked from places 60, 61 respectively to the smoke flues 31 and 32 rather than vice versa.

 This venturi effect is very important, since this avoids direct evacuation of the heating gases from the lower part of the smoke flues 31 and 32 to the compartment 57 without having to provide a sealing device between the lower ends of the water channels 15 and 16 and the upper wall of the water channel 19.

 Because a continuous opening remains between the ends of the aforementioned water channels 15, 16 and the upper end of the water channel 19 over the entire length of the boiler, the soot, the fly ash and the dust which deposit on the water channel 19, can simply reach, by sliding, in the lower part of the smoke ducts 31 and 32, then arriving in the dust separation chamber 55, 56, as is the case for soot, fly ash and dust depositing on the walls of smoke flues 27, 29, 31 and 28, 30, 32.

 The dimensions of the passage section of the so-called precipitation chamber 57 are chosen so that the speed of the gases moving towards the chimney is less than the speed at which the particles entrained in dust and soot fall. In this way, these particles of dust and soot can be recovered from the fact that, in this precipitation chamber, they have time to swirl out of the smoke gases to descend to the bottom of this chamber, in other words , on the upper wall of the water channel 19.

 In addition, by tilting the water channels 21-22, the smoke gases are accelerated at points 62 and 63, thus ensuring, in chambers 55 and 56, a more powerful cyclone effect and better separation of dust. Between the lower edge of each water channel 21-22 and the surface 64 is formed a slot 65, 66 which, during the operation of the boiler, fills with ash and dust, so that it does not there is no loss of draft from the chamber 54 towards one of the chambers 55 and 56. However, the dust and the soot being in the chambers 55, 56 can be constantly drawn through the small doors 6 towards the burner 4 by means of '' a tacky, hook or the like, if these dusts were piled up too high in the chambers 55 and 56. In this way, the separate dusts themselves form the tight seal between the chambers 55-56 and chamber 54, so that it is not necessary to provide a metal sealing device, which would be quickly damaged at the temperature prevailing there.

 So that the upper wall of the boiler, the upper wall of the water channel 19 and the outer walls of the water channels 9 to 18 remain free of dust, soot or fly ash, it is possible, at appropriate times, move the rows of slats 35, 36 and 37 to thereby also move the slats 53 and animate the cleaning elements 41 to 52 with a back-and-forth movement, all these movements being able to take place while the boiler is in service .

 In this way, the dust, soot and scraped fly ash fall by themselves through the smoke flues, either directly into the chambers 55, 56, or first of all onto the water channel 19 and then, below the water channels 15 and 16 as far as the chambers 55, 56 where these dust and ashes are, as has already been exposed, attracted towards the hearth where the collected soot is subjected to combustion complementary, while the dust agglomerates with the coal ash undergoing sintering.

 In this way, a combustion chamber is obtained in which the gases carry out an exclusively vertical or practically vertical movement, a cleaning device being incorporated into this boiler, while the various smoke flues and the water channels are installed in such a way. so that the soot, the fly ash and the dust are separated by a cyclone effect, a precipitation chamber being also provided for separating the soot and the ash from the gases moving towards the chimney.

 The boiler according to the invention does not require any extractor, since both the different smoke flues are installed so that there are different venturi effects, thus also making it possible to obtain a dedusting device operating automatically while, in providing a built-in cleaning device, the combustion boiler is, in a way, self-cleaning, so that the cleaning and dust removal doors can be omitted.

 In a slightly modified variant of embodiment, as shown diagrammatically by a plate 67, 68 respectively, the passages situated below the water channels 15-16 will be closed, these plates or closing devices which, preferably, will consist of several parts, being pushed upwards by the slats 53 during the movement of the latter in order to let pass the dust and the soot. In this case, the width of the smoke flue 31 can remain constant or not over the entire height, thus causing or not the aforementioned venturi effect.

 FIG. 1 also schematically represents an alternative embodiment according to which, above the water channels 21-22, refractory bricks 69 are fitted, the latter being placed at well-determined distances from one another in order to form passages for smoke gases. The slots or passages made between these bricks 69 may or may not be different from each other but, preferably, in the center of the boiler, in other words, above the hearth, the passages will be smaller than those directed towards the ends of the boiler.

 By using bricks of this type, radiation is obtained on the hearth ensuring better combustion; better spreading of the flames is obtained, thus also improving the yield while, at the location of the aforementioned bricks 69, an afterburning of the unburnt gases is obtained.

 In addition, it is obvious that the present invention is in no way limited to the embodiments described above by way of example and illustrated in the accompanying drawings, but that the combustion boiler according to the invention can be carried out in any shapes and dimensions without departing from the scope of the invention.

Claims (18)

CLAIMS.  1.- Heating boiler for the combustion of coal, this boiler being of the type formed by two end collectors (7-8) connected to each other by water channels between which smoke flues are formed , characterized in that two of the water channels (21-22) are installed near and above the burner (4) diverging from bottom to top; above these two water channels (21-22), there is an inverted U-shaped water channel (19); on either side of this U-shaped water channel (19), at least one vertical water channel (9-10) is installed; next to the latter and at a well-defined distance, a second vertical water channel (15-16) is provided, placed above the relevant lateral edge of the U-shaped water channel (19), leaving a passage so long at the bottom than at the top; next to each of the second water channels mentioned last, there is a third vertical water channel (17-18) which, at the top, forms a tight seal with the upper wall of the boiler and which, in the bottom, leaves a passage to a dust precipitation chamber (57) opening into the chimney (3).  2. A heating boiler sui.vant claim 1, characterized in that the lower edges of the divergent water channels (21-22) are located at a certain distance from the bottom (64) of the boiler.  3. A heating boiler according to claim 1, characterized in that the lower ends of the flanges (23-24) directed towards the bottom of the water channel in the form of U inverted (19) are located at a lower level than the upper edges of the aforementioned divergent water channels (2122).  4. A heating boiler according to claim 1 or 3, characterized in that the body of the aforementioned U-shaped water channel (19) is produced in the form of an inverted V.  5.- Heating boiler according to one of the preceding claims, characterized in that, in the case of a single water channel (9-10) placed vertically next to each side edge of the U-shaped water channel ( 19), this single channel extends over the entire height of the boiler.  6.- Heating boiler according to one of the preceding claims, characterized in that, in the case of several vertical channels (9-10-11-12-13-14) located near each side of the U-shaped channel (19), the channel occupying the extreme external position (9-10) extends over the entire height of the boiler, while the channel occupying the extreme internal position (13-14) is arranged so that its lower edges terminate at a level below that of the lower end of the flanges (2324) directed towards the bottom of the inverted U-shaped water channel (19), while its upper edges terminate at a well-defined distance from the upper wall (2) of the boiler.  7. A heating boiler according to claim 6, characterized in that, as much the lower ends as the upper ends of the above-mentioned vertical water channels (9 to 14), are arranged in steps, the highest water channels being located outside.  8.- Heating boiler according to one of the preceding claims, characterized in that the widths of the smoke flues (27-28-29-30-31-32), formed between the above-mentioned vertical water channels, between them and between the water channel (13-14) occupying the extreme interior position with the flange (23-24) adjacent to the inverted U-shaped water channel (19), are equal.  9. Heating boiler according to one of the preceding claims, characterized in that, at the top, the aforementioned second water channel (15-16) ends at a level located lower than that of the neighboring vertical water channel (13-14).  10.- Heating boiler according to claim 8 or 9, characterized in that the opening formed between the lower edge of the second water channel (15-16) is closed by a movable sealing plate (67-68) .  11.- Heating boiler according to one of the preceding claims, characterized in that the distance between the aforementioned second water channel (15-16) and the neighboring vertical water channel (13-15) is greater than the distance between this same water channel (13-15) and the flange concerned (23-24) directed towards the bottom of the water channel in the shape of an inverted U (19).  12.- Heating boiler according to one of the preceding claims, characterized in that the lower edge of the above-mentioned third vertical water channel (17-18) is situated at a level significantly higher than that of the above-mentioned second vertical water channel ( 15-16), the distance between the third (17-18) and the second (15-16) vertical water channel being at least equal to the sum of the distances between the water channels located on one side the second water channel (15-16).  13. Heating boiler according to one of the preceding claims, characterized in that the so-called dust precipitation chamber (57) has dimensions calculated so that the speed of the ascending gases is less than the speed at which the fly ash, the soot or dust present in these gases falls.  14.- Heating boiler according to one of the preceding claims, characterized.en that refractory bricks (69) are placed, providing intermediate spaces, on the two water channels (21-22) installed alongside and au- above the burner (4).  15.- Heating boiler according to one of the preceding claims, characterized in that it comprises a cleaning device formed by rows of horizontal slats (35-36-37) bearing on the upper edges of the water channels, these slats (35-36-37) being connected to each other by one or more bars (38-39-40) one end of which protrudes outside the boiler, from where they can be operated, while that, on these horizontal slats, bars, slats, chains or the like (41 to 52) are suspended vertically in the smoke flues (27) formed between the water channels so that by moving the above-mentioned horizontal slats , the above bars, slats, chains or the like vertical elements (41 to 52) are also moved along the walls of the water channels (9 to 18).  16.- Heating boiler according to claim 15, characterized in that, on the water channel in the form of an inverted U (19), slats or the like (53) providing the shape of this water channel are provided. (19), these slats (53) being fixed to two or more bars, chains or the like suspended downwards, forming part of the cleaning device.  17. A heating boiler according to claim 15 or 16, characterized in that three rows of horizontal slats are provided, in particular a row (37) above the aforementioned precipitation chamber (57), the ends of these slats horizontal resting on the upper edges of the aforesaid third vertical water channels (17-18), as well as two similar rows of horizontal slats (35-36) each resting on a first (11-12) and a third (17-18) ) vertical water channel.  18. A heating boiler according to one of the preceding claims, characterized in that it comprises an access door (6) at least at one end but, preferably, at both ends.