Boiler

© Start of patent period: 1984 11 15 Longest possible duration:

t issued: 1985 07 10

Inventor:

© dependence:

© Pamphlets considered to delineate the prior art:

AT 378 257

Nr.378257

The invention relates to a heating boiler for burning liquid or gaseous fuels, in particular for smaller power ranges, consisting of a water-bearing housing made of sheet steel, in which a liquid-tight cross through the front and rear walls of the housing chamber for receiving the combustion chamber and the Heizgaszüge with upstream Deflection chamber is arranged, which chamber of a plurality of distributed over the entire circumference, is surrounded in spaced juxtaposed Zugkanälen, which are in communication with the flue gas collection chamber with flue, wherein the front and rear walls sweeping chamber is designed as a thin-walled, in Kondensatkritischen areas unprocessed gray cast iron and the Zugkanäle from cast on the inner surface of the cast iron body, in the area the combustion chamber radially inwardly directed and the combustion chamber sleeve supporting webs are formed.

Such a boiler is known according to AT-PS no. 78270, in the design principle, for example, but also according to CH-PS no. 485182 and AT-PS no. 282884.

Although these latter boilers may meet the requirements set for possible heat usability, practical implementation and cost-effective production pose considerable problems, which is why the two latter boilers could presumably not be introduced to the market.

When heating boiler according to AT-PS no. 78270 on the other hand, the favorable performance characteristics and on the other hand, the good processability of steel combined, where also by the formation of the chamber of gray cast iron training is included with the training and thus eliminates all welding in this area. With regard to the advantage of such a boiler is supplementary to note that it allows the material combination steel sheet / casting provided there to accommodate the corrosion behaving, flame and heating gas-carrying part of gray cast within a water-bearing housing made of sheet steel with one or more hot water tanks, which in the case of boilers made only of cast iron, in practice because of the complexity of the cast members, connected with sealing problems is not possible. Also, it allows the proposed material combination steel sheet / cast to arrange several such gray cast iron body within a steel housing on top of each other and operate with separate burners, so that a heat demand adapted operation is possible.

Experiments with the boiler according to the AT-PS no. 78270 have now shown that this can be further improved, in particular in terms of condensate control, and therein is also the object of the invention.

This object is achieved with a boiler of the type mentioned according to the invention in that the gray cast body is formed over at least a portion of its length as a slimmer, converging to the exhaust side truncated cone and at least in the lower front wall area is provided with a Kondensatstaubord.

If one uses namely the boiler of the type mentioned above for sliding temperatures, must be expected with a considerable amount of accumulating condensate. It has been found that it is very difficult to make the sealing of the door to the gray cast body so that no condensate penetrates through the seal. The seal is dissolved and destroyed. The condensate, consisting of sulfuric acid and sulphurous acid, then runs down the outside of the boiler and destroys the boiler body and / or the insulating jacket.

If you open a boiler for cleaning and afterwards the shutter is not properly screwed, then even with perfect seal, the boiler then although gas-tight, but does not need to be liquid-tight. For this reason, it is advantageous to design the boiler so that condensate can accumulate in a larger amount before the closure and evaporates there, without this condensate enters the seal between the closure and boiler body.

The same applies to the back of the boiler, if the boiler back wall is not cast and the back closure is screwed on as a casting. Also there must be a step, ie, the diameter of the closure opening and boiler rear wall must be smaller, if possible, be much smaller than the inner diameter of the gray cast iron body.

Nr.378257

- 3 The lower the temperature of the hot gases, the more they tend to condense, ie, the combustion gases in the rear of the boiler in the flue gas collecting chamber condense the most and form the most condensate.

Since the temperature of the combustion gases is relatively low and thereby the tendency and the possibility to evaporate accumulated condensate is not very large, it is advantageous to make the gray cast body so that the condensate forward into the hot zone of the boiler, after Possibility flows into the deflection chamber. This is, as mentioned, achieved by forming the gray cast body either conical overall or this front tapers to a quarter or a third of the length, for example, zyindrisch and then tapered backwards.

If one makes the gray cast body as a whole conical, it is advisable to conically form the cup-like combustion chamber to be inserted. In such an embodiment, namely, there is the advantage that you can form the mounting unit with a so-called green core, ie, the gray cast iron body would be shaped and molded vertically. Due to the conicity of all surfaces in the boiler and if one makes the cast-on ribs thinner at the front than at the back, the mold could be made so that the core is normally formed from sand inside. It can be cast in this way, the boiler rear wall with the same, including the Ausputzöffnüng and the opening for a ring, which is used to complete the flue pipe. The production costs would be lower in such a casting process, as if the gray cast iron body is to be cast inside with separately prepared cores, which would be necessary for cylindrical gray cast iron bodies.

On the one hand to save on manufacturing costs, but on the other hand, to initiate forces for pressing the closures, as far as they are not already cast with the gray cast iron in the cast gray iron, but also in some ways to make the production more efficient, for example, hinges or mounting cams cast on the gray cast iron body at the front or cast on the back of the gray cast iron body.

The gray cast iron body, which is conical only in the rear, can still be equipped with a cylindrical combustion sleeve, since the taper of the gray cast iron body to the rear, although a reduction of cast-on ribs for the trains in height brings with it. Basically, this is not a disadvantage, but an advantage, because it must be assumed that the combustion gases that flow through the trains, give off heat, become colder and thereby assume an ever smaller volume on the way through the hot gas flues to the flue , Thus, if the cross-section of the trains decreases backwards due to the conicity of the gray cast iron body, the heating gases can pass through the trains at approximately the same flow velocity, thereby increasing the heat transfer.

The invention advantageously and additionally trained boiler is explained in more detail with reference to the drawings of exemplary embodiments. FIG. 1 shows a longitudinal section through an embodiment of the heating boiler; FIG. 2 shows a cross section through the trained as an installation unit gray cast iron body; 3 shows a simplified longitudinal section through another embodiment of the gray cast body; 4 shows a simplified longitudinal section through a further embodiment of the gray cast body; 5 shows a simplified longitudinal section through yet another embodiment of the gray cast body; 6 shows a partial section through a particular embodiment of the gray cast body and Figure 7 shows a section through a particular embodiment.

In the drawings, with -1- the chamber forming a mounting unit, flame and flue gas carrying chamber of a tubular gray cast body -2-, with -3, 4- the front and rear walls of the water-bearing housing -6- made of sheet steel, with -5- the inner surface of the cast iron body -2-, on which the combustion chamber sleeve -7- supporting webs -8- and the less high webs -8'- in the region of one hand the deflection chamber -9- and on the other hand the flue gas collecting chamber -10- arranged or are molded with, and denoted by -11- the burner-side Kondensatstaubord.

According to Fig.l of the gray cast body -2- is a total of frusto-conical shape, wherein the abutment edges -12- of the webs for the loose-fitting combustion chamber sleeve -7-, which consists for example of stainless steel, extend in a cylindrical plane. That's inevitable

Nr.378257

In the case of this embodiment, if the boiler is moved at a sliding temperature, the condensate that forms is not allowed to reach the seals -13- for the closures -14- that could otherwise be eaten away. In this embodiment, condensate dust fences are located at the ends of the the installation unit forming gray cast iron -2- provided. Incidentally, the conicity of the inner surface 5 ensures that the condensate which precipitates, in particular in the lower half of the boiler, passes forwards into the part of the boiler which is exposed to hot flue gases.

According to Figure 3, the abutment edges -12'- of the webs -8- parallel to the conical inner surface -5- extending formed. The same also applies to the embodiment of Figure 4, in which the gray cast body as a whole, as can be seen bell-shaped cast, so with back-molded closure -14'-, which also has a connection piece -15'- for the withdrawal of the flue gases.

The connection of the installation unit or the gray cast body -2- with the steel sheet housing -6- is shown in Fig.l advantageous without any Sch white work effort, which would be liquid-tight in the combination of steel / cast iron considerably and not always with certainty, if one taken into account the different thermal stresses.

For this purpose, the gray cast iron body -2- on the outside with machined surfaces -16- and with Anlagingbunden -17- provided, the front and rear walls -3, 4- with their Ringbundabkröpfungen -18- to the stop to the Anlagingbunde -17- and with the addition of lubricants and sealants -19- be pressed. The inner diameter of the Ringbundabkröpfungen -18- are for this purpose kept correspondingly smaller than the outer diameter of the surfaces -5- on gray cast iron body -2-.

With much greater effort, however, could be a liquid-tight connection in the sense of Fig.6 produce, the front and rear wall -3, 4- with the interposition of sealing rings or the like. against Ringflanschanschlüsse -20- of the gray cast body -2- laid and bolted to it.

In order not to have to initiate by the attachment of the closures -14- resulting loads in the sheet-steel housing -6-, the gray body -2- with corresponding sprues -21- (Fig.2), whereby the mounting unit and the support function for these parts takes over.

In Figure 5 is shown very simplified, as a partial frusto-conical gray body -2- would look like.

Figure 7 shows a particular embodiment of the connection formation, wherein the cranked opening edge -22- is held slightly conical and also the Preßsitzfläche -23-, in front of which a small annular collar -24- is arranged, behind which a small groove can be provided. The outer diameter of the annular collar -24- is approximately between the largest and the smallest diameter of the cranked opening edge -22- of the annular collar.

When pressing snaps the narrower end of the cranked opening edge -22- on the annular collar -24- and is thus additionally secured against the Innendruek. Should leaks really occur, such a position can be secured by means of a suitable bandage.

The installation unit made of cast iron could also be oval-shaped in cross-section, ie be designed in the sense of a slot cross-section with main axes, which have only a small difference in length, with the larger main axis is vertical.