DE8517158U1 - Glow insert for furnaces, especially heating boilers - Google Patents

Description

Eduard Wandzel
Oilseed oil for oven, especially

The invention relates to a glow plug insert for ovens, in particular heating boilers according to the generic term of patent claim 1.

Stoves, in particular heating boilers for operating farm water heaters or for producing hot domestic water, are known in numerous designs. Also known in particular are stoves or heating boilers in which the fuel outlet is formed by the nozzle of a blower burner for liquid fuels and in which a liquid is heated in the combustion chamber by the flame of the blower burner |

interspersed, tubular glow insert* is provided. With &rgr;

The aim of the glow insert is to achieve the best possible combustion of the liquid fuel (oil) in the flame of the fan burner, and in particular by ensuring that the components of the liquid fuel that are not or only incompletely burned, which are carried along on the outside of the flame, evaporate on the glow insert, which is hot during operation of the furnace, and are returned to the flame in this state for complete combustion (afterburning). While it was previously suggested that such glow inserts be made of stainless steel, it has recently been suggested that glow inserts be made of ceramic, as these have a longer service life than those made of stainless steel.

The object of the present invention is to demonstrate an annealing insert for furnaces or heating boilers which, with a simple and inexpensive structural design, leads to a significantly more favorable heat recovery in relation to the afterburning processes within the combustion chamber compared to known annealing inserts.

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To solve this problem, a heating element* for ovens, in particular heating boilers, is designed in accordance with the characterizing part of patent claim 1.

The glow insert according to the invention or its tube section can be manufactured relatively easily and therefore, above all, inexpensively from ceramic. The glow insert achieves optimal combustion of a liquid, but also gaseous fuel and above all optimal afterburning of the part of this fuel that has not yet been burned or has only been burned insufficiently, whereby in particular the inwardly drawn sections of the peripheral wall of the individual pipe sections, which are formed at the ends of these pipe sections with a smaller diameter, on the one hand form openings or channels with a large cross-section for recirculation of air or gases within the combustion or flame area between the pipe sections at their overlapping points, and inwardly projecting noses or bridges are formed inside the pipe sections, which cause or cause a division of the flame at least on its circumference, so that the flame builds up again at these noses or behind them in the direction of the flame, so that intensive "turbulence" also occurs within the flame, through which (turbulence) the afterburning processes are significantly improved.

Because of the very intensive combustion and in particular because of the intensive afterburning processes, the exhaust gases of a furnace or heating boiler equipped with the glow insert according to the invention contain practically no unburned residues, so that it is possible to design the furnace as a heating boiler in such a way that the combustion chamber is directly surrounded by the inner walls of the boiler that receives the pickling or service water, whereby in this design of the heating boiler the combustion gas (flue gas) is then discharged via a flue gas duct to further increase the efficiency, which is located between a thermally insulated outer wall of the heating boiler and the outer walls of the boiler.

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The glow insert according to the invention is preferably used in conjunction with a blower burner for liquid or gaseous fuel, whereby "gaseous fuel" in the broadest sense is also understood to mean an air-coal dust mixture. The glow insert can also be an integral part of a burner.

Further developments of the invention are the subject of the subclaims.

The invention is explained in more detail below with reference to the figures and an embodiment. Bs pointers

Fig. 1 in a schematic representation and in section a furnace designed as a heating boiler together with a blower burner for liquid fuel and with a glow insert arranged in the combustion chamber, which is formed by three pipe sections or rings;

Fig. 2 shows an enlarged side view of the annealing insert of the furnace according to Fig. 1;

Fig. 3 is a plan view of the end with smaller cross-section of one of the tube pieces of the glow insert;

Fig. 4 is a schematic representation to illustrate the distribution of the V-shaped channels around the axis of the annealing insert when using several pipe sections for this annealing insert;

Fig. 5 shows an enlarged detailed view of a longitudinal section of the annealing insert in the area of the overlap of two pipe sections;

Fig. 6 shows a method of fastening the pipe sections of the glow insert in another embodiment.

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In the figures, the number "1" generally designates a heating boiler with a combustion chamber 2. In the illustrated embodiment of the heating boiler 1, the combustion chamber 2 is directly delimited on the sides, i.e. on its two vertical sides, at the top and preferably also at the bottom and at the back, by the boiler 3 which receives the heating or service water, or by its inner walls 4, 5 and 6, whereby the outer surface of the wall 7 is covered with a pre-layer made of foamed ceramic material. In contrast to conventional heating boilers, in which an intermediate wall is arranged between the inner walls of the boiler and the combustion chamber, a significantly improved efficiency is achieved simply because the heat generated by the flame 7 of the self-burning boiler 6 is reduced. The heat generated in the combustion chamber 2 is transferred directly to the Kess®! 3 or its inner walls 4 and 5.

The aforementioned intermediate wall can be omitted in the heating boiler 1 because a glow insert S is provided in the combustion chamber 2, which is located at the farthest point from the wall 7 of the fan burner S, which will be explained in more detail below and which ensures almost complete combustion of the fuel (preferably oil) fed to the fan burner 8, so that there is no risk of deposits of unburned components or residues on the walls 4, 5 and 6.

The heating boiler 1 has outer walls 10, 11 and 12, which delimit the interior of the heating boiler on the two vertical sides, on the underside, on the top and on the back, whereby these walls, which are also provided with thermal insulation, are arranged in such a way that a flue gas or exhaust gas channel 16 is formed between their inner surfaces and the outer walls 13, 14 and 15 of the boiler 3, which completely encloses the boiler 3 and leads to a Xamin connection 17 provided in the wall 12.

On the outer walls 13 and 14 of the boiler 3, fins 13 are provided which extend into this boiler and into the flue gas duct IS, which are only shown schematically*! in Fig. 1 and also contribute to a significant improvement in the transfer of the heat contained in the flue gas to the water absorbed by the boiler 3.

At the front of the heating boiler, i.e. on the left side in the illustration chosen for Fig. 1, the interior of the heating boiler, which accommodates the combustion chamber 2, the boiler 3 and the flue gas duct 16, is closed off by a front wall 19. The fan burner 8 is also attached to this front wall, which extends through the front wall 19 into the combustion chamber 2 with a part 8' having the burner nozzle. The arrangement is further such that the inner surface of the front wall 19 is at a distance from the wall sections 20 that border the interior of the boiler 3 at the front, so that the flue gas channel 16 continues between these wall sections 20 and the inner surface of the front wall 19 into the combustion chamber 2 or is connected to the combustion chamber 2 in the area between the wall sections 20 and the inner surface of the front wall 19. The flow direction of the hot combustion gases flowing around the boiler 3 inside and out is indicated in Fig. 1 with the arrows A.

The heating insert 9 made of ceramic or ceramic material is shown in detail in Fig. 2-5. In the embodiment shown, this heating insert consists of three rings or pipe sections 21a, 21b and 21c made of ceramic, each of which is open at both ends and which are truncated conically shaped on their peripheral wall 22, i.e. are designed in such a way that each pipe section has a substantially circular cross-section with the larger diameter D at one end and a maximum cross-section with the smaller diameter d at the other end. The information "I)" and "d" refer to the inner cross-section.

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section, which differs from the corresponding external cross section by twice the wall thickness of the peripheral wall 22.

As shown in particular in Fig. 1, the glow insert 9 consisting of the three pipe sections 21a, 21b and 21c is arranged in the combustion chamber 2 in such a way that all pipe sections are coaxial in their axes and coaxial with the flame 7 and are also arranged in such a way that for each pipe section the end with the larger diameter D is closer to the bulb burner 8 or its nozzle than the end with the smaller diameter d.

As shown in particular in Fig. 2, the pipe sections 21a, 21b and 21c are further arranged relative to one another in such a way that the pipe section 21a closest to the fan burner 8 extends with its end with the diameter d into the end with the larger diameter D of the pipe section 21b, which follows the pipe section 21a with increasing distance from the fan burner 8. Furthermore, the pipe section 21b extends with its end with the smaller diameter d into the end with the larger diameter D of the pipe section 21c, which follows the pipe section 21b with greater distance from the fan burner 8. It is understood that if necessary (depending on the expansion of the flame 7 or depending on the thermal output of the fan burner 8 and thus of the heating boiler 1 in the direction of the longitudinal extension of the flame 7 and depending on the spray angle of the nozzle of the fan burner) more than three or fewer than three pipe sections can be arranged in an interlocking manner in the manner described.

The diameters D and d of the pipe sections 21a, 21b and 21c are matched to one another in such a way that where the pipe section 21a extends into the pipe section 21b or the pipe section 21b extends into the pipe section 21c, ring gaps 23 are formed between the interlocking pipe sections, through which combustion gases can escape from the interior of the glow insert t at high pressure, as shown in Fig. 2 with

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indicated by arrow B. In order to prevent unburned or insufficiently burned quantities or droplets of liquid fuel (Ul) _from being carried along with the escaping combustion gases at high pressures (arrow B), at least the pipe sections 21a and 21b are provided with an inward-reaching flange 24 (Fig. 5) at least in the area of the annular gap 23, which serves as a "scraping edge" for any unburned or insufficiently burned parts (droplets) of the liquid fuel carried along in the area of the flame 7, ie it retains these unburned or incompletely burned parts of the liquid fuel and feeds them to the combustion process (final combustion).

As Fig. 3 further shows, the circumference 22 of at least the pipe sections 21a and 21b is shaped or

drawn inwards in some areas in such a way that it forms three channels on its outer surface, evenly offset around the longitudinal axis L of the sliding block 9, extending in the direction of the longitudinal axis L and with an approximately V-shaped cross-section, which are open towards the outer surface of the peripheral wall 22 and towards the end with the smaller diameter d. These channels 25, whose extension in the direction of the longitudinal axis L is greater than half the length of the respective pipe sectionβ in this axial direction, preferably approximately four fifths of the length of the respective pipe section, have a depth t which increases with decreasing distance from the end with the smaller diameter d.

Through the channels 25 or through the inwardly drawn partial areas 22' of the peripheral wall 22 forming these channels, which (partial areas) can also be referred to as bridges, three noses are formed in the interior of the relevant pipe section, evenly distributed around the longitudinal axis L, the height of which extends radially to the longitudinal axis L increases with decreasing distance from the end with the smaller diameter d. The height of these noses is of course equal to the depth t plus the thickness of the peripheral wall 22, i.e. of the section 22'.

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In a preferred embodiment of the invention, the maximum height of the grooves formed by the channels 25 is approximately in the range of 1/4 d to 1/6 d.

The channels 25 formed by the inwardly drawn areas or bridges 22' result in openings with relatively large diameters between the nested blanks 21a and 21b or 21b and 21c for a circulation flow, as indicated by the arrow C in Fig. 2.

The noses created by the bridges 22 and extending into the interior of the pipe sections create a division of the flame 7 at least in its edge area, whereby with a corresponding displacement of the noses created by the bridges 22' around the longitudinal axis L from pipe section to pipe section, a multiple deflection of the flame 7 at its outer areas and thus a certain turbulence in the flame are simultaneously forced, which also leads to a significant improvement in the combustion process, in particular also of the components of the liquid fuel that hit the surfaces of the pipe sections 21a, 21b and 21c during operation and evaporate there, and which were originally not yet or insufficiently burned. Precisely because of this deflection or turbulence effect, the pipe section 21c preferably also has the noses formed by the bridges 22', whereby the flanges or splash sections 24 are then also provided on this pipe section at least in the area between the three bridges 22'.

Fig. 4 shows the offset arrangement of the noses of all pipe sections 21a, 21b and 21c formed by the bridges 22'.

If all pipe sections have the same number of bridges 22' and if these bridges are offset from one another around the longitudinal axis L by the same angle or with the same pitch T, then the individual pipe sections 21a, 21b and 21c are offset from one another in such a way that

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arranged offset from one another, so that each pipe section following a pipe section with increasing distance from the fan burner 8 is offset or rotated relative to the first-mentioned pipe section by the amount of a ■ T/η u about the longitudinal axis L, where η is the number of pipe sections used. In the embodiment shown, the angle a is thus 40°, since three pipe sections 21a, 21b and 21c are provided and the pitch T on each pipe section with three noses or bridges 22' is 120°.

In a preferred embodiment of the invention, the diameters D and d of the pipe sections are selected such that the annular gaps 23 have a width of approximately 9 mm in the radial direction to the longitudinal axis L. In addition, the pipe sections 21a, 21u and 21c are designed with regard to their diameters D and d in accordance with the following table, so that the average cross section of the glow insert remains the same from the end facing the blower burner 8 to the end facing away from the blower burner 8.

Table 21a 9 mm 21b 5 mm 21c 1 mm 146, 2 mm 157, 7 mm 168, 4 mm D 129, 139, 150, d 4 6 6 H

However, it is also advantageous in the illustrated embodiment of the glow insert 9 that the individual pipe sections 21a, 21b and 21c can be attached to one another in a different way or order than that shown in Fig. 2, or that more than three or fewer than three pipe sections can be connected to one another to form the glow insert, depending primarily on the power, the size and design of the combustion chamber, the pump pressure for the liquid fuel and the spray angle of the nozzle of the fan burner 8. The annular gap can also be larger or smaller than

The diameter D also increases with a larger annular gap, so that the greater the distance from the fan, the greater the effective cross-section for the glow plug. The shape (M) of the bridges 22' can also be different for the individual pipe sections, as shown in the table above in sections N.

The individual pipe sections 21a, 21b and 21c are connected to one another or held together by the fact that angle elements made of corrosion- and heat-resistant material (e.g. stainless steel) are attached to the outer surface of the peripheral wall 22 of these pipe sections with one leg, the other leg of which has a hole. Threaded rods are passed through these holes in the angle elements 26, which carry nuts 28, whereby each angle element 26 or its leg protruding from the peripheral surface of the relevant pipe section is firmly clamped between two nuts 28. This not only achieves a particularly simple and effective attachment of the pipe sections 21a, 21b and 21s, but also provides the possibility of an exact position adjustment of the individual pipe sections relative to one another.

Fig. 6 shows a different type of fastening for the pipe sections 21a, 21b and 21c to one another than that shown in Fig. 2. In this embodiment, the pipe sections are provided with a flange 29 that projects radially outwards over the outer circumferential surface at their ends that have the larger diameter D. A strip 30 made of corrosion-resistant material (stainless steel) that is bent into an approximately Z shape is used for fastening. One leg (30') rests against the inner surface of the pipe section in question. The flange 29 is also surrounded by a circular bracket 31 made of corrosion-resistant flat material (stainless steel), one leg of which is connected to the middle section 30" of the strip 30 by means of a screw 32, so that the pipe section is held in the area of the flange 29 between the leg 30' and the bracket 31. The other leg of the strip 30 is connected to the

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a perforated plate 34, to which several similar fastening devices of the type described above are attached for all three roller pieces 21a, 21b and 21c. It goes without saying that several fastening devices (each consisting of the perforated plate 34, the strip 30 and the bracket 31) are provided offset around the longitudinal axis L. The individual perforated plates 34, each of which lies with its longitudinal extension in the direction of the axis L, are connected to one another to form a frame or cage by several transverse webs (not shown) running transversely or perpendicularly to this axis. By using the perforated plates 34, which each have a large number of holes for the screws 33 in their longitudinal extension, it is possible to choose the arrangement of the individual pipe sections 21a, 21b and 21c to one another in accordance with the respective requirements. In principle, it is also possible to assemble each perforated plate 34 from several sections 34", which then overlap in the area of the screw 33 and are connected to one another there.

The invention has been described above using an example embodiment. It is understood that changes and modifications are possible without thereby departing from the inventive concept underlying the invention.

For example, with the fastening method shown in Fig. 6, it is also possible to design the element 31 not as a bulky bracket, but as a Z-shaped element, in which the leg resting on the section 30" points upwards, as is indicated in Fig. 6 at 31' with broken lines. This simplifies the fastening using the screw 32, since no threaded hole, which is difficult to produce, is then required in the element 31 made of corrosion-resistant material, but only a simple hole. The screw is held in place by a threaded nut in this case.

In the embodiments shown in the figures, the inner surfaces of the tube covers 21a, 21b and 21c form an angle of approximately 12.5° with the longitudinal axis L, whereby the

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RohX'stUcke are formed in a truncated cone shape along their entire length on the inner surface. In contrast to this, it is also possible to provide the pipe sections with a short cylindrical or circular section at the end of the larger diameter D, as is indicated in Fig. 5 with the interrupted line 22". This design has the advantage that in the area of the ends of the larger diameter a greater thickness for the peripheral wall 32 and thus greater strength is obtained, which can be of particular importance for the type of fastening shown in Fig. S. Furthermore, the cylindrical or circular sections 22 have the advantage that in the lower part of the annealing oil insert there is a horizontal collecting surface on the inlet side of each pipe section for such unburned fuel that is on the annealing oil insert. could not yet evaporate. This sintering surface effectively prevents fuel from dripping downwards from the glow plug.

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Claims (5)

Expectations 1. Glow insert for a furnace, in particular a heating boiler, which is tubular and made of ceramic, characterized in that the glow insert (9) consists of at least two pipe sections (21a, 21b, 21c) each open at both ends, each pipe section being frustoconical on its peripheral wall (22) and having a first end with a larger cross section (D) and a second end with a smaller cross section (d), that at least one pipe section (21a, 21b) extends with its second end into the first end of an adjacent pipe section (21b, 21c) in such a way that at least one annular gap (23) is formed between the pipe sections (21a, 21b; 21b, 21c) overlapping or interlocking in this way. and the circumferential edge (22) of the pipe section (21a, 21b) at the second end of a pipe section (21a, 21b) projecting into an adjacent pipe section (21b, 21c) is drawn inwards in at least three areas (22') offset about the longitudinal axis (L) of the pipe section in such a way that on the outer surface of the circumferential wall (22) of the pipe section, channels (25) are formed which are open towards this outer surface and towards the second ends and are approximately V-shaped in cross section, which extend in the longitudinal direction of the pipe section and whose depth increases towards the second end, and in the interior of the pipe section, noses protruding inwards from the circumferential wall with a height which increases towards the second end of the pipe section. 2. Glow insert according to claim 1, characterized in that all tube parts (21a, 21b, 21c) of the glow insert (9) have the inwardly drawn regions (22') at their second end. 3. Glow insert according to claim 1 or 1, characterized in that the inwardly drawn regions (22') of two adjacent tube pieces (21a, 21b» 21c) are each offset from one another by a certain angular amount (a) about the longitudinal axis (L) of the QlQh insert (9). 4. Glow insert according to one of claims 1 to 3, characterized in that the pipe pieces (21a, 21b, 21c) are fastened to one another by means of continuous, rod-like elements (27). 5. Glow plug insert according to one of claims 1 to 4, characterized in that the pipe pieces (21a, 21b, 21c) each have a radially inwardly extending flange or flange section (24) at their second end at least between the inwardly drawn areas (22').