EP0848781B1 - Heat-insulated composite profiled section - Google Patents

Abstract

The outer and inner profiled metal sections (3,4) are joined by a mating profiled insulating rib (5,6) fitting in grooves in them. The insulating rib comprises two parallel walls (6.1,6.2) joined by transverse ribs so as to form lengthwise chambers (11). Dependent on the degree of resistance required to heat-transfer, the width of the insulating rib is 20,30,40 or 50 mm. The chamber width is equal to or less than the insulating rib width where the chamber height is 5 mm. or less, and wall thickness also regulates the resistance to heat transfer.

Description

The invention relates to a thermally insulated Composite profile, especially for windows, doors, Facades or the like, consisting of outer and inner metal profiles that have at least one with Insulation bridge provided with connection profiles connected and spaced apart, the connection profiles in the grooves of the Metal profiles grip and the insulating bridge two in essentially parallel, a cavity between them has defining boundary walls, wherein between the Boundary walls transverse to them can be arranged, whereby the cavity in Inside the isolating web in several, towards arranged one behind the other between the metal profiles Hollow chambers is divided.

Such thermally insulated composite profiles are known for example from DE 42 38 750, the Insulating web or the insulating webs for a thermal Separate the outer and inner metal profiles.

When dimensioning the insulating bars, it should be noted that that the heat transfer from the warmer to the colder Metal profiles are made in three different ways can, namely by heat conduction, by heat radiation as well as by heat entrainment (convection), whereby in the Usually all three transport mechanisms side by side occur.

In heat conduction, heat energy is transferred between directly adjacent parts of solid bodies or immobile liquids or gases. The degree of heat conduction in the present case is made up of the proportion of heat that flows over the boundary walls on the one hand and the still air inside the cavity or the hollow chambers and the air space adjacent to the outside of the insulating web on the other. The proportion of heat flowing over the insulating web is essentially influenced by the thickness and width of the boundary walls and the thermal conductivity of the material. However, the mechanical parameters (strength, thickness, wall thickness, width) likewise determine the mechanical properties of the statically load-bearing insulating web which forms a spacer. The further reduction in heat conduction is therefore usually limited for structural reasons (wall thickness, width). In the case of thermal radiation, on the other hand, a transmitting medium is not required, so that the dimensioning of the insulating web is insignificant insofar as shading, reflections or the like influencing the radiation by the insulating web are not to be taken into account.

When carrying the heat, heat energy flows to it Liquids, gases or vapors due to thermal conduction or possibly also transmit radiation and carried along by the current. Since the heat transfer medium the absorption of heat energy reduces its density and consequently experiences a buoyancy, which causes Heat transfer itself as free convection designated heat flow.

It has now been shown that the design of the Isolierstegs not the proportion of heat carry insignificantly influenced, so that it is the task of present invention is, in composite profiles type mentioned the design of the insulating web to improve so that the convection, ie the proportion heat transfer, limited to such a value is that the resulting heat transfer from is of the same order of magnitude as pure heat conduction with still air, and that at the same time the Radiation exchange (heat transfer through long-wave Infrared radiation) is reduced. This is supposed to a 30% reduction in heat loss achieved compared to the current state of the art become.

This object is achieved according to the invention in that - starting from a wall thickness s = 0.5 mm and a thermal conductivity lambda = 0.35 W / mK of the boundary walls - to achieve a thermal resistance of the insulating web in the range between 0.15 m ² K / W and 0.30 m ² K / W the width (D) of the insulating web measured in the direction of the spacing of the metal profiles, the width in the range between 0.25 m ² K / W and 0.50 m ² K / W (D) of the insulating web 30 mm, in the range between 0.35 m ² K / W and 0.65 m ² K / W the width (D) of the insulating web 40 mm, in the range between 0.40 m ² K / W and 0.80 m ² K / W the width (D) of the insulating web is 50 mm, the width (d) of the cavity or the hollow chamber also measured in the direction of the spacing of the metal profiles being less than or equal to the width (D) of the insulating web and is greater than or equal to one third of the width (D) of the insulating web, as long as the height of the cavity or the hollow chamber is less than or equal to 5 mm, and at a height of the cavity or the hollow chamber in the range above 5 mm to 20 mm and at least one transverse web present, the ratio of the height (h) to the width (d) of the hollow chamber is greater than or equal to 0.2 and less than or equal to 5, wherein further the wall thickness (s) lies in the range between 0.25 mm and 1.0 mm with a dependence of the thermal resistance on the wall thickness (s) according to the relationship R (s) = R (s = 0.25 mm) + (s - 0 , 25) / 0.25 * delta R and with a range of values for delta R between 0.025 and 0.05, and with a 10% increase in the thermal conductivity of the boundary walls in the range between 0.15 W / mK and 0.40 W / mK leads to a reduction of the thermal resistance by 2 to 4%.

Intermediate values in the relationship between the interval the thermal resistance and the width (D) of the Insulating bars can be linearly interpolated.

Even more favorable conditions result if at a height of the cavity or cavity in the Range over 5 mm to 20 mm and at least one existing crossbar the ratio of height (h) to Width (d) greater than or equal to 0.5 and less than or is equal to 2.

The aspect ratio of the vertical height (h) to the horizontal width (d) of the cavity or the hollow chambers can in particular be such that, taking into account the temperatures to be expected on the outer and inner metal profiles, the square of this aspect ratio multiplied by the Rayleigh Number (Ra _h ), smaller than the numerical value 72.

The dimensionless Rayleigh number Ra _h is the product of the Grashof number and the Prandtl number that characterizes only the material properties of the fluid in the enclosed cavity, which can be assumed for air to be Pr = 0.71. The size of the Grashof number is a measure of the heat that is transported due to convection from the warm to the cold side of the cavity or hollow chamber. If the geometry of the insulating web, that is to say the aspect ratio h / d of the cavity or the hollow chambers, is selected taking into account the expected temperature conditions so that the product of the square of the aspect ratio and the Rayleigh number remains smaller than the numerical value 72 This ensures that convection is restricted within the cavity or the hollow chambers to such an extent that the heat transfer is of the same order of magnitude as with pure heat conduction in still air.

In a preferred embodiment of the invention, the Number of hollow chambers depends on the width and height of the insulating bar and the specified aspect ratio determine.

It has also proven to be advantageous if the wall thickness of each of the two boundary walls is in the range between 0.4 mm and 1.0 mm.

A preferred embodiment of the invention is characterized in that the insulating web has three hollow chambers and the geometry ratio related to the outer contour of the insulating strip (width D and height H) within the interval 1.3 * D - 0.022 * D ² <H <4.14 * D -0.088 * D ² .

In the context of the invention, it has also proven to be advantageous if the thermal conductivity L of the boundary walls is between 0.17 and 0.35 W / (mK). It is also advisable to select the width of the boundary walls that determines the distance between the metal profiles depending on the wall thickness so that the specific heat flow q ₀ , i.e. the heat flow through a 1 m long strip at delta T = 1 K, over the boundary walls flows, remains less than 0.02 W.

The advantages achieved in this are essential that in training the Insulating bars according to the specified characteristics except optimal thermal insulation also with regard to achievable strength of the insulating bars a cheap Vote is reached. This dimension lies further based on the knowledge that for the Insulating webs in question materials, especially PVC, polypropylene and polyamide, in this Order of increasing thermal conductivity have. To increase their mechanical strength enlarge, aggregates are often in this Materials that, while strength, at the same time, however, increase the thermal conductivity.

If the width of the boundary walls is chosen to be small, so the load on the insulating web is small, at the same time, however, increases due to the low Way between the two metal profiles Heat conduction. On the other hand, due to the lower load with lower aggregates be worked, which in turn the Thermal conductivity decreases.

The proposed according to the invention Parameter combination thus sets the frame, within which, in addition to optimum thermal insulation also the required strength of the insulating bridge is achieved. Even with a larger width of the Boundary walls become the one that then enters Deterioration of the heat flow due to the dimensioning of the air pockets, due to the profit overcompensated.

It is further proposed within the scope of the invention that the wall thickness of the boundary walls and / or the Thermal conductivity of the boundary walls in the predetermined interval chosen so small enough are that the width of the boundary walls in the area is between 20 and 50 mm.

In addition, it has in the context of the invention as exposed advantageously when the clear distance the boundary walls in the range between 1 and 15 mm lies. However, it is particularly favorable if the clear distance of the boundary walls in the area is between 5 and 10 mm.

The crossbar or crossbars can expediently perpendicular to the Boundary walls aligned and fixed with these be connected. However, it is basically also possible that the between the cross bar and the Boundary walls formed angles in the area between 75 ° and 105 °.

In the context of parameter optimization, it did furthermore proven to be advantageous if the Wall thickness of the two boundary walls in the area is between 0.5 mm and 0.8 mm.

Finally, a further advantageous embodiment the invention characterized in that the Connection profiles symmetrical (center) to the insulating bridge are arranged.

Fig. 1

einen einzelnen Isoliersteg in schematischer Darstellung, wie er der Ermittlung der Bemessungsgrundlagen dient,

Fig. 2

ein Verbundprofil in einer Schnittdarstellung,

Fig. 3

eine weitere Ausführungsform in der Fig. 2 entsprechender Darstellung.

In the following the invention is explained in more detail using exemplary embodiments shown in the drawing; show it

Fig. 1

a single insulating bridge in a schematic representation, as it serves to determine the design bases,

Fig. 2

a composite profile in a sectional view,

Fig. 3

another embodiment in FIG. 2 corresponding representation.

1 is of the thermally insulated composite profile, especially for windows, doors, facades or the like is provided, the outer and inner Metal profile 3, 4 indicated and with each a connection profile 5 on both sides provided insulating web 6, the two Metal profiles 3, 4 connects together and on Keeps a distance from each other.

The insulating web 6 has two essentially parallel, forming a cavity between them Boundary walls 6.1.6.2, whereby between the Boundary walls 6.1,6.2 running transversely to them Crosspieces 10 are arranged, whereby the cavity in the Inside of the insulating web 6 in several, in Longitudinal direction of the insulating web 6 one behind the other arranged hollow chambers is divided.

The heat transfer can be taken into account transport mechanisms mentioned at the beginning calculate appropriate procedures. Will that Aspect ratio of vertical height (h) to horizontal width (d) of the cavity or Hollow chambers varies, so it shows that the Share of heat transfer from warmer to colder Metal profile on convection in the hollow chambers 11 declines, by appropriate choice of Aspect ratio can be reduced so that his share compared to the heat conduction and the Heat radiation becomes insignificant.

If you wear the thermal resistance for different widths of the insulating web 6 over the Height of the insulating web, there is an area in which the thermal resistance is a maximum owns. This shows that when considering the the outer and inner metal profiles 3, 4 expected temperatures and suitable choice of Aspect ratio of the hollow chambers an improvement thermal insulation can be achieved. Even with one Plotting the dependency of the Thermal resistance of the height of the Insulating web for different wall thicknesses shows a maximum for a certain range of values. The variation in wall thickness does result because of the changing heat conduction to one as expected Change in total thermal resistance; the influence of However, the convection component can also be seen here.

This can be used for dimensioning the insulating bridge in take advantage of the following:

Starting from a wall thickness s = 0.5 mm and a thermal conductivity lambda = 0.35 W / mK of the boundary walls 6.1.6.2, a thermal resistance of the insulating web in the range between 0.15 m ² K / W and 0.30 m ^{2 is achieved} K / W the width (D) of the insulating web to 20 mm, in the range between 0.25 m ² K / W and 0.50 m ² K / W the width (D) of the insulating web to 30 mm, in the range between 0, 35 m ² K / W and 0.65 m ² K / W the width (D) of the insulating bridge to 40 mm, in the range between 0.40 m ² K / W and 0.80 m ² K / W the width (D ) of the insulating web is set to 50 mm. The width (d) of the cavity or hollow chamber is chosen to be less than or equal to the width (D) of the insulating web and greater than or equal to one third of the width (D) of the insulating web, as long as the height of the cavity or hollow chamber 11 is smaller or is 5 mm. With a height of the cavity or the hollow chamber in the range above 5 mm to 20 mm and at least one transverse web 10 present, the ratio of height (h) to width (d) is chosen to be greater than or equal to 0.2 and less than or equal to 5. If the wall thickness (s) is varied in the range between 0.25 mm and 1.0 mm, the thermal resistance is dependent on the wall thickness (s) according to the relationship R (s) = R (s = 0.25mm) + ( s - 0.25) / 0.25 * delta R and with a range of values for delta R between 0.025 and 0.05. An increase in the thermal conductivity of the boundary walls (6.1,6.2) by 10% in the range between 0.15 W / mK and 0.40 W / mK leads to a reduction in the thermal resistance by 2 to 4%, which is correspondingly the case with the initially selected output variables is taken into account.

When determining the shape of the insulating web can then proceed in such a way that the number of Hollow chambers 11 from the width and height of Isolierstegs and the specified aspect ratio certainly.

If the insulating web has three hollow chambers 11, the aspect ratio can be estimated in a simplified manner: The geometric ratio relating to the outer contour of the insulating strip (width D and height H) should then be 1.3 * D - 0.022 * D ² <H <4 within the interval , 14 * D -0.088 * D ² . Corresponding interval specifications can be made for a different number of hollow chambers 11. In the exemplary embodiments shown in FIGS. 2 and 3, the composite profile is used in a window, of which, however, only the lower sash profile and frame profile cross section are shown.

Both the frame profile 1 and that Wing profile 2 are a thermally insulated composite profile trained and also consist of outer 3 and inner 4 metal profiles, each with two with Connection profiles 5 provided insulating webs 6 connected and at a distance from each other are held. The essentially dovetail-shaped connecting profiles 5 engage positively in the grooves of the Metal profiles 3, 4.

The glass pane 7 itself is over Glazing seals 8 by means of a glazing bead 9 on Wing profile 2 held.

The insulating webs 6 in turn have two essentially parallel boundary walls 6.1, 6.2, that form a cavity between them. The Boundary walls 6.1, 6.2 are over several Crosspieces 10 connected to each other, the number of Crosspieces 10 from the boundary conditions already explained is dependent.

In the illustrated in Figs. 2 and 3 In exemplary embodiments, the crosspiece 10 is rectangular aligned to the boundary walls 6.1, 6.2 and firmly connected to them. However, there is Possibility of this crossbars 10 under one Angle between 75 ° and 105 °, possibly even under one even larger angles to the boundary walls 6.1, 6.2 to the extent that this does not result in too much significant deterioration in thermal insulation occurs.

The wall thickness of the boundary walls 6.1, 6.2 can in Range between 0.4 mm and 1 mm, the Wall thicknesses of the two boundary walls 6.1, 6.2 are equal to each other. To be particularly advantageous it has been shown if the wall thickness of the Boundary walls 6.1, 6.2 in the range between 0.5 mm and 0.8 mm.

When selecting the materials for the boundary walls 6.1, 6.2, care must be taken that the thermal conductivity L is between 0.17 and 0.35 W / (mK). It should be taken into account that the addition of additives to the material increases the strength, but at the same time increases the thermal conductivity, so that a compromise must be found within the interval proposed according to the invention and the wall thickness of the boundary walls 6.1, 6.2, but it does allows the specific heat flow q ₀ , i.e. the heat flow through a 1 m long strip at delta T = 1 K, which flows over the boundary walls 6.1, 6.2, to remain smaller than 0.02 given the corresponding width and wall thickness of the boundary walls 6.1, 6.2 Watt. Since the width of the boundary walls 6.1, 6.2 leads to an increased load, the wall thickness of the boundary walls 6.1, 6.2 and / or their thermal conductivity in the predetermined interval should be chosen to be sufficiently small that the width of the boundary walls 6.1, 6.2 is in the range between 20 and 50 mm.

2 are the Connection profiles 5 symmetrical, i.e. in the center of Insulating web 6 arranged. However, there is also Possibility to connect the connection profiles 5 asymmetrically Insulating web 6 to be arranged, especially if Insulating webs 6 with comparatively far from each other spaced boundary walls 6.1, 6.2 application Find. Such an example is in FIG. 3 shown, in which both insulating webs 6 in Frame profile 1 and the upper insulating web 6 in Wing profile 2 in the manner just described are trained. There is also the possibility the distance of the boundary walls 6.2 Insulating webs 6 in the frame profile 1 of the Boundary walls 6.1 to enlarge even further.

Claims (15)

1. A heat-insulated composite profile member, in articular for windows, doors, facades or the like, comprising outer and inner metal profile members (3, 4) which are connected together and held at a spacing from each other by way of at least one insulating bar (6) provided with connecting profile portions (5), wherein the connecting profile portions (5) engage into receiving grooves in the metal profile members (3, 4) and the insulating bar (6) has two substantially parallel boundary walls (6.1, 6.2) forming a cavity between them, wherein transverse bars (10) can be arranged between the boundary walls (6.1, 6.2) in a position of extending transversely with respect thereto, whereby the cavity in the interior of the insulating bar (6) is subdivided into a plurality of hollow chambers (11) which are arranged in succession in the direction between the metal profile members (3, 4), characterised in that - based on a wall thickness s = 0.5 mm and a thermal conductivity lambda = 0.35 W/mK of the boundary walls (6.1, 6.2) - to achieve a thermal resistance (R) of the insulating bar in the range between 0.15 m²K/W and 0.30m²K/W the width (D) of the insulating bar as measured in the direction of the spacing of the metal profile members (3, 4) is 20 mm, in the range between 0.25 m²K/W ana 0.50 m²K/W the width (D) of the insulating bar is 30 mm, in the range between 0.35 m²K/W and 0.65m²K/W the width (D) of the insulating bar is 40 mm, and in the range between 0.40 m²K/W and 0.80 m²K/W the width (D) of the insulating bar is 50 mm, wherein the width (d) of the cavity or the hollow chamber as also measured in the direction of the spacing of the metal profile members (3, 4) is smaller than or equal to the width (D) of the insulating bar and greater than or equal to a third of the width (D) of the insulating bar as long as the height (h) of the cavity or the hollow chamber (11) is less than or equal to 5 mm, and wherein with a height (h) of the cavity or the hollow chamber in the range above 5 mm to 20 mm and with at least one transverse bar (10) being present the ratio of the height (h) to the width (d) of the hollow chamber (11) is greater than or equal to 0.2 or less than or equal to 5, wherein moreover the wall thickness (s) is in the range between 0.25 mm and 1.0 mm with a dependency of the thermal resistance (R) on the wall thickness (s) in accordance with the relationship:
   R(s)=R(s=0.25 mm) + (s-0.25)/0.25 * delta R, and with a value range for delta R of between 0.025 and 0.05, and wherein an increase in the thermal conductivity of the boundary walls (6.1, 6.2) by 10% in the range between 0.15 W/mK and 0.40 W/mK leads to a reduction in the thermal resistance by 2 to 4%.
2. A neat-insulated composite profile member according to claim 1 characterised in that with a height of the cavity or the hollow chamber (11) in the range above 5 mm to 20 mm and with at least one transverse bar (10) being present the ratio of the height (h) to the width (d) is greater than or equal to 0.5 and less than or equal to 2.
3. A heat-insulated composite profile member according to claim 1 or claim 2 characterised in that the sides ratio of the vertical height (h) to the horizontal width (b) of the cavity or the hollow chambers (11) is such that having regard to the temperatures to be expect at the outer and inner metal profile members (3, 4) the square or product of that sides ratio multiplied by the Rayleigh number (Ra_h) is less that the numerical value 72.
4. A heat-insulated composite profile member according to one of claims 1 to 3 characterised in that the number of hollow chambers (11) is determined from the width and height of the insulating bar and the predetermined sides ratio of the hollow chambers.
5. A heat-insulated composite profile member according to one of claims 1 to 4 characterised in that the wall thickness of each of the two boundary walls (6.1, 6.2) is in the range of between 0.4 mm and 1.0 mm.
6. A heat-insulated composite profile member according to claim 5 characterised in that the insulating bar has three hollow chambers and the geometrical relationship related to the external contour of the insulating bar (width D and height H) is within the range 1.3*0 - 0.022*D² < H < 4.14*D - 0.188*D².
7. A heat-insulated composite profile member according to one of claims 1 to 6 characterised in that the thermal conductivity L of the boundary walls (6.1, 6.2) is between 0.17 and 0.35 W/(mK).
8. A heat-insulated composite profile member according to one of claims 1 to 7 characterised in that the width of the boundary walls (6.1, 6.2), which determines the spacing between the metal profile members (3, 4), is so selected in dependence on the wall thickness that the specific heat flux q₀, that is to say the heat flux through a 1 m long bar with delta T = 1 K, which flows by way of the boundary walls (6.1, 6.2), remains less than 0.02 W.
9. A heat-insulated composite profile member according to one of claims 1 to 8 characterised in that the wall thickness of the boundary walls (6.1, 6.2) and/or the thermal conductivity of the boundary walls (6.1, 6.2) are so selected to be sufficiently small in the predetermined range that the width of the boundary walls (6.1, 6.2) is in the range of between 20 and 50 mm.
10. A heat-insulated composite profile member according to one of claims 1 to 9 characterised in that the internal spacing of the boundary walls (6.1, 6.2) is in the range of between 1 and 15 mm.
11. A heat-insulated composite profile member according to one of claims 1 to 10 characterised in that the internal spacing of the boundary walls (6.1, 6.2) is in the range of between 5 and 10 mm.
12. A heat-insulated composite profile member according to one of claims 1 to 11 characterised in that the transverse bar (10) is oriented at a right angle with respect to the boundary walls (6.1, 6.2) and is fixedly connected thereto.
13. A heat-insulated composite profile member according to one of claims 1 to 11 characterised in that the angle formed between the transverse bar (10) and the boundary walls (6.1, 6.2) is in the range of between 75° and 105°.
14. A heat-insulated composite profile member according to one of claims to 13 characterised in that the wall thickness of the two boundary walls (6.1, 6.2) is in the range of between 0.5 mm and 0.8 mm.
15. A heat-insulator composite profile member according to one of claims 1 to 15 characterised in that the connecting profile portions (5) are arranged symmetrically (centrally) with respect to the insulating bar (6).

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