EP0691440B1 - Building block with insulating hollow spaces - Google Patents

Description

The invention relates to a , preferably cuboid, building block according to the preamble of claim 1. A building block of this kind e.g. in EP-A-0599283 and can also be a brick be. It is used to create heat-insulating walls and is with adhesive, thin bed, medium bed or a fibrous mortar that does not fall into the cavities, bricked up. The cavities can be parallel to the wall surface run vertically, as with so-called perforated bricks, or also horizontally.

With conventional insulating modules, such as Perforated bricks, gas concrete blocks and building blocks cement-bound lightweight materials, attempts are being made Thermal insulation ability by using a possible optimize light building material. That's why you use highly porous clay for bricks, foamed concrete, Pumice, pearlite or the like. But this technology finds its way Limits in the limited compressive strength of the Lightweight materials.

It is also state of the art, the thermal insulation to improve by clever arrangement of louvers, the transverse to the heat flow direction from one side of the block go through others completely or at least for the most part. In particular, improve aligned in the longitudinal direction of the stone and offset against each other transversely to the heat flow direction slit-shaped cavities the thermal insulation ability. The elongated, extruded for bricks and therefore continuous cavities weaken the Cohesion, especially the transverse tensile strength of the Insulating blocks. Therefore, a minimum of Cross-sectional area of heat-conducting webs in The heat flow direction must not be undercut.

It is known that for a given thickness of the transverse to Longitudinal webs the optimal flow average slot width or the average Number of consecutive in the heat flow direction Let slot holes be calculated (Swiss Patents 476 181, 482 882 and 516 057). Under the mean slot width is understood as Cross-sectional area of a generally elongated cavity divided by its largest dimension across Heat flow direction. The number of slot holes will be averaged over a variety of in the heat flow direction guided cuts through the brick. It corresponds to one more common parameter, namely the number of Rows of slots. The cavity cross sections usually face oblong shapes such as ellipses across the heat flow direction, Rectangles, trapezoids, cuboids, triangles, etc. The cavities can also be square, round, five, six and have polygonal shapes.

For blocks made of fired clay, the web thickness is 6 mm and more common. If the web thickness is reduced, for example to 4 or 2 mm, so increases based on the above mentioned patents the optimal number of slot holes very strongly, so that brick with the theoretically determined optimal number of slots rows can no longer be produced can, because when extruding the clay masses much too high Pressures arise. For example, one would have to be 30 cm thick Brick with a web thickness of 2 mm according to Leitner (see above CH-PS 516 057) or Amrein (see above CH-PS 476 181) Slotted hole width is 3.5 mm. That would be over 50 Row of slotted holes necessary to achieve the theoretically determined To reach the maximum approximately. Today produced 30 cm thick Bricks usually have 17 rows of slots, maximum 21 rows of holes. 30 rows of holes are currently a borderline case represent the producibility.

Another way to use heat insulating blocks Manufacture is described in FR-A-2192226 and consists of the block with several to create larger cavities and to keep heat loss in to limit the cavities with them afterwards Insulating inserts made from a wide variety of materials fill, but this is a complex operation.

Conventional insulation modules using these methods have been optimized, achieve thermal conductivity values of 0.12 W / mK or worse, for bricks at best 0.15 W / mK.

The invention is based, to isolating modules create the statically resilient to a conventional extent are, but have a much better thermal insulation than previously known, and are easier to produce.

Starting from a module of the type described in the introduction this task is characterized by the characteristic of Claim 1 and by the claimed process features solved.

The heat transfer in an insulating block of the type mentioned takes place on the one hand by heat conduction in the base material, d. H. in the walkways, and on the other hand by convection, conduction and Radiation in the cavities. Have more recent insights show that especially with blocks with thin webs the proportion of heat transport through the air-filled dark voids on the entire heat transfer is significant. Furthermore, the heat transport in the Cavities by radiation. This outweighs the shares of the Heat transport through conduction in the air and through Convection. Heat transfer by convection is in Slot holes with a height of 25 cm up to a slot width of about 3 cm next to the radiation component small and also smaller than the heat transfer through the heat conduction in the air. The large theoretical number of webs one of the above This is basically the only reason why fonts are optimized necessary because the bridges like umbrellas always Interrupt heat radiation. The same happens with known ones Building blocks whose cavities are filled with insulating materials are. For cavities that are much wider than 3 cm the insulated inserts also prevent convection all filled cavities, especially those with one Widths of 3 cm and smaller result in the insulated inserts but primarily an interruption in heat radiation. The Still air alone would be without convection and radiation optimal isolator.

While it is well known for insulation purposes heat reflective surfaces on the front from heat radiation too protective objects, especially at high ones Temperatures and against solar radiation. Drawing on that mentioned knowledge that the heat radiation in the cavities a surprisingly high influence even at room temperature has, the invention proposes this possibility Reduction of heat radiation through heat reflective Surfaces in the cavities of insulating blocks too use. It should be noted that in the interest of the maximum Use the coating the optimal number of rows of holes must be defined.

Fortunately, it was found that building blocks with inner cavities coated with heat reflecting wider cavities can be provided than if the Cavities are uncoated. It is therefore proposed that Contrary to the formulas according to the ones mentioned at the beginning Swiss patents fewer and broader To provide rows of slots. With this, more heat-conducting webs can be saved and that Thermal insulation capacity of the block can be further increased will. These wide internal cavities don't just bring an additional insulation gain, but also improve the producibility of the building block.

The coated inner cavities do not need to to be provided with additional insulation inserts because the coating of the cavities is due to the heat exchange Radiation between the opposing ones Ridges delimiting the cavity are sufficiently reduced. However, the cheapest thermal conductivity values are included Cavity widths less than 3 cm realized, otherwise Convection currents can arise in the cavity. From the same reason is the height of the cavity to a stone height of usually 25 cm and make sure that the cavities do not connect to channels when bricked up, but separated from each other by a layer of mortar. This can be achieved in particular in that a building block with large cavities up to three centimeters wide next to this also has small cavities that when bricking be sealed by the mortar used and the cover large cavities. In any case, it is about make sure that not too much mortar falls into the cavities, these dirty, partially fills and thus the insulation behavior lowers. In particular, it makes sense to have finger holes heat reflective to coat and arrange so that they do not overlap when bricking in the usual offset. With Such modules become an advantage in the immersion process bricked up, d. H. just a few millimeters into the mortar dipped and mixed with the mortar adhering to the stone.

By largely preventing heat radiation in the Cavities is a reduction in the total heat transfer in the cavities at the usual climatic temperatures in the Cavities possible by more than half. For example is the coefficient of thermal conductivity for coated inside Slotted holes with a width of approx. 2 cm less than 0.05 W / mK instead over 0.11 W / mK for uncoated cavities.

When using this technique on good insulation modules, the Made from lightweight materials using the traditional method and with regard to the hole width and the number of holes take into account the heat reflective coating, succeeds in building blocks for structurally resilient insulating walls without additional insulation with thermal conductivities below 0.10 W / mK to manufacture.

In a development of the invention it is proposed that except the cavities also the butt sides of the insulating blocks are coated with heat reflecting. This is especially true for Blocks that have recesses on the butt sides that after placing on a next stone in the same position with its depressions to closed cavities combine. So these cavities are also on theirs Inside surfaces coated.

The heat reflective layer can be aluminum or a contain similar heat reflective component. In question there are also various oxides such as zirconium oxide, titanium oxide, Magnesium oxide etc. The heat-reflecting component can in Clay, in a glaze, a varnish or any Cover layer embedded or connected with an adhesive layer be.

A preferred method of applying the heat reflective layer is that this on the traditionally produced insulating block or is sprayed on. Especially with bricks suggested that if a smooth surface is necessary before applying the heat reflecting layer as Underlay for this a glaze is applied. This forms a hard, smooth surface on which z. B. Aluminum can be evaporated or sprayed on. Instead of vapor deposition can also use special ceramic or inorganic masses are sprayed on afterwards be branded.

The cavities can also be coated by spraying a synthetic resin paint with reflective components done because the coating does not have high temperatures is exposed.

Another method, the surfaces of To coat insulating modules, in particular bricks, is that the mass to be molded or the clay water-soluble products with a low Emission coefficients are added. During the Drying and firing processes migrate to the Surfaces of the blank and coat it evenly. If this on the wall-parallel outer surfaces Coating is undesirable, this can be brushed off or be sanded.

Another possibility of coating is that a glaze containing the heat reflecting component is co-extruded with the molding. The glaze is included great pressure over the cores of the mouthpiece.

The effectiveness of a heat reflective coating can be by the so-called emission coefficient ε specify numerically. With burnt clay it is or cement-bound lightweight building materials without coating 0.93, at aluminum-coated surfaces, on the other hand, only 0.05. Paintings with aluminum bronze have one Emission coefficients ε of about 0.20 and therefore quite suitable for coating the cavities.

Fig. 1

die Draufsicht eines Bruchstücks eines Hochlochziegels mit wabenförmig angeordneten sechseckigen Hohlräumen (Wabenziegel),

Fig. 2

die entsprechende Draufsicht eines Hochlochziegels mit versetzten rechteckigen Hohlräumen (Schlitzlochziegel),

Fig. 3

die entsprechende Draufsicht eines Hochlochziegels mit elliptischen Hohlräumen,

Fig. 4

die Draufsicht eines ganzen Ziegels mit Grifflöchern im kleineren Maßstab,

Fig. 5

ein Kurvenschaubild, das bei einem Hochlochziegel bestimmter Abmessungen unter bestimmten Voraussetzungen die rechnerische Abhängigkeit des Wärmedurchlaßwiderstandes R von der Anzahl n der Lochreihen darstellt, und

Fig. 6 und 7

entsprechende Kurvenschaubilder, bei denen andere Parameter gelten.

Exemplary embodiments of insulating modules in which the invention is implemented are described below with reference to the drawing. This also shows some arithmetically obtained graphs that underline the importance of the invention. In detail shows

Fig. 1

the top view of a fragment of a perforated brick with honeycomb-shaped hexagonal cavities (honeycomb brick),

Fig. 2

the corresponding top view of a perforated brick with offset rectangular cavities (slotted perforated brick),

Fig. 3

the corresponding top view of a perforated brick with elliptical cavities,

Fig. 4

the top view of an entire brick with handle holes on a smaller scale,

Fig. 5

a graph showing the mathematical dependence of the thermal resistance R on the number n of rows of holes in a perforated brick of certain dimensions under certain conditions, and

6 and 7

Corresponding graphs where other parameters apply.

In Figures 1 to 3 there is a neighboring tile indicated by dash-dotted lines. The cavities are on theirs Wall surfaces coated with heat reflecting. A corresponding coating is of course included any shape of the cavities possible.

At the abutting surfaces 1, these bricks are designed so that the the respective hole pattern should be added to adjacent brick ends. Accordingly, not only are the inner surfaces of the cross section differently shaped, to the storage area of the brick vertically running holes 2 heat reflecting coated, but also the butt surfaces 1 to also the Inner surfaces of the trapezoidal, rectangular or to capture wedge-shaped grooves in which after the Joining the bricks also through heat transfer Radiation takes place. On the visible sides 3 are the Wall thickness of the brick 6 mm thick. The The wall thickness of the inner webs is 3 mm.

1 has 15 rows of holes. Masonry made with such bricks achieves a k-value of 0.38 W / m ² with a wall thickness of 30 cm unplastered, taking into account the standardized heat transfer coefficients and with a thermal conductivity of the cullet material of 0.30 W / mK for non-reflecting inner surfaces K. The emission coefficient of the clay surface is 0.93. If the surfaces are reflective with an emission coefficient ε = 0.1, a k-value of 0.25 W / m ² K is achieved instead of 0.38 W / m ² K.

4 is the honeycomb pattern refined again. The brick floor plan measures 30 in natura x 27 cm. There are 21 rows of holes in the heat flow direction realized. Another special feature of this brick are two embedded handle holes 4 and each on the butt sides a half-cavity 5. These half-cavities complement each other in Add another brick to an entire cavity. Of course, here as in the previous ones Examples of all cavities and the butt sides be heat reflective coated. A very cheap one Influence can also be expected if only that Handle holes 4 and the half-cavities 5 accordingly are coated. This brick has four on one end vertical springs 6 each containing a hexagonal cavity, which engage in corresponding grooves 7 of the neighboring tile.

In Figures 5, 6 and 7 the influence is one heat reflective coating of the cavities on the Thermal resistance R and the theoretically optimal Number n of rows of slots of a 30 cm wide and 25 cm high building blocks with different bridge widths graphically shown. These representations apply to the following Requirements: The thermal conductivity of the body is 0.30 W / mK, which are the two outer edge webs on the visible surfaces twice as thick as the inner bars. Heat conductive Cross bars made of clay are neglected, as are the Heat transfer through convection currents, making the Validity of the diagrams on hole widths of a maximum of 3 cm remains limited. Generally the Thermal resistance R of the brick with increasing quality the coating and the optimal number n of Row of slotted holes decreases, the slotted holes becoming wider will. The emission ratio ε that this Calculation between 0.05 and 0.9 with three intermediate levels was changed in Fig. 5 for the individual curves specified. One sees that with increasing quality the heat reflective coating, d. H. with smaller ones Emission ratio ε, the thermal resistance R not only gets bigger in principle, but the curve shape changes so that a maximum becomes visible at all. At Fig. 7 (web thickness 6 mm) this is particularly clear.

It can be seen that with blocks coated with Cavities in more than 25 rows of slots Thermal resistance R with web thicknesses of 4 mm and 6 mm very strong and decreases even at 2 mm. It is therefore not useful with the cavities of building blocks Slit hole widths less than 8 mm reflect heat coat.

Claims (10)

1. Building block with a plurality of empty internal cavities which extend over the entire height of the building block and are 8 to 30 mm wide in the heat flow direction and with webs which are less than 6 mm thick and separate the cavities, characterized in that the internal surfaces of the cavities (2) are provided all around with a heat-reflecting coating.
2. Building block according to claim 1, characterized in that the abutting surfaces (1) are also provided with a heat-reflecting coating.
3. Building block according to claim 1, characterized in that larger cavities such as handling holds (4) are provided with a heat-reflecting coating and are so arranged that the cavities are not directly superimposed when constructing walls with the building blocks.
4. Building block according to claim 1, characterized in that the heat-reflecting coating contains aluminium or a similar heat-reflecting component such as other metals or oxides.
5. Walling produced using building blocks according to one of claims 1 to 4 assembled using adhesive, thin-setting, medium-setting or fibrous mortar, so the cavities are not filled or contaminated with mortar.
6. Method of producing building blocks, in particular bricks, according to one of claims 1 to 4, characterized in that a water-soluble heat-reflecting component is added to the clay raw material, this component travelling to the surface, even of the cavities, during the drying and baking process and coating them.
7. Method of producing building blocks, in particular bricks, according to one of claims 1 to 4, characterized in that the heat-reflecting layer is applied to bricks by coextrusion.
8. Method of producing building blocks according to one of claims 1 to 4, characterized in that the heat-reflecting layer is applied by vaporization or atomization.
9. Method according to one of claims 6 to 8, characterized in that the heat-reflecting layer of bricks is optionally burnt in only after the baking thereof.
10. Method according to one of claims 6 to 9, characterized in that, prior to application of the heat-reflecting layer, a glaze is applied as a substrate therefor.

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