NL2028045B1

NL2028045B1 - Roof drain

Info

Publication number: NL2028045B1
Application number: NL2028045A
Authority: NL
Inventors: Adrianus Baijense Leendert
Original assignee: Dyka B V
Priority date: 2021-04-22
Filing date: 2021-04-22
Publication date: 2022-11-02

Abstract

The invention relates to a roof drain comprising a. mounting shell having a support flange, and. a bottom funnel having a bottom spout for receiving and draining off water, wherein the roof drain comprises a ring wall that 5 inwardly merges into a gutter wall that extends downwards and under an angle with respect to the ring wall, wherein the roof drain comprises multiple first reinforcement walls that are distributed. around. an outer side of the gutter wall and that merge into the ring wall and into the gutter 10 wall, wherein the roof drain comprises a thermal insulation ring having a top surface that faces the ring wall, and first accommodation slots that extend from the top surface, wherein the first reinforcement walls are accommodated in the first accommodation slots.

Description

P139495NL00 Roof drain

BACKGROUND The invention relates to a roof drain to drain off rainwater from a roof construction, in particular a flat roof construction.

A known roof drain for a flat roof construction comprises an aluminum funnel having a support flange that merges via multiple concentric steps into a bottom spout. The bottom spout is connected to rainwater tubing that is suspended under the roof construction. The funnel is manufactured by pressing and rolling the steps into a flat aluminum plate.

SUMMARY OF THE INVENTION A disadvantage of the known roof drain is that the concentric steps that are rolled into the aluminum plate form relatively weak areas, in particular at the edges between the steps. The roof construction and the rainwater tubing that is connected with the bottom spout regularly move with respect to each other, for example due to the weight of rainwater that falls on the roof construction and that subsequently passes through the suspended rainwater tubing. In the long term this leads to crack initialization in the aluminum. During rainfall, the rain water that is drained off temporary cools down the aluminum funnel, whereby moisture may condensate against the side of the funnel that is embedded in the roof construction. This condensation causes oxidation in the initial cracks, which expands and causes leakage of the funnel. Furthermore, the condensation may also accumulate inte water droplets which in the long run damage the roof construction. Taking into account a typical funnel outer diameter of more than 30 centimeter, another disadvantage of the known roof drains employing aluminum is that it is quite heavy and difficult to handle.

It is an object of the present invention to provide a roof drain that can withstand or absorb small movements between the roof construction and the rainwater tubing that is connected to it, that may have a decreased weight and/or that has improved moisture resistance.

The invention provides a roof drain comprising a mounting shell having a support flange for mounting the roof drain in a roof construction, and a bottom funnel having a bottom spout for receiving and draining off water, wherein the roof drain comprises a ring wall between the support flange and the bottom spout that extends parallel to the support flange, and that inwardly merges into a gutter wall that extends downwards and under an angle with respect to the ring wall, wherein the ring wall and the gutter wall are concentric with respect to the bottom spout, wherein the roof drain comprises multiple first reinforcement walls that are distributed around an outer side of the gutter wall and that merge into the ring wall and into the gutter wall, wherein the roof drain comprises a thermal insulation ring having a top surface that faces the ring wall, and first accomodation slots that extend from the top surface, wherein the first reinforcement walls are accommodated in the first accommodation slots.

The roof drain according to the invention comprises a ring wall and a gutter wall that are under an angle with each other, which angle is reinforced by means of the distributed first reinforcement walls. This provides a lightweight roof drain having rigidity around the ring wall and the gutter wall, which are thermally insulated by the thermal insulation ring. Other parts, such as the support flange which rests on the roof construction, may be thermally insulated by the roof construction itself, for example by means of prescribed additional glass wool. In this manner the water conducting parts that are in contact with the drained off rainwater can cool down without risk of damage caused by moisture condensation. In the roof drain according to the invention the rigidity is located at the ring wall and the gutter wall, whereby deformations that are for example caused by small movements between the roof construction and the rainwater tubing that is connected to the bottom spout, are diverted to parts that can better withstand such deformations due to their location or specific properties. Examples of such parts are a relatively large support flange, or a long bottom spout.

In an embodiment the angle is 45-90 degrees.

In an efficient embodiment the first reinforcement walls extend radially from the outer side of the gutter wall.

In an embodiment the first reinforcement walls are straight reinforcement walls.

In an embodiment the top surface of the thermal insulation ring abuts the funnel mounting flange to ensure an optimal thermal insulation of the funnel mounting flange.

In an embodiment the thermal insulation ring forms a bottom surface of the roof drain, which can be brought in contact with abovementioned additional glass wool for example to form one continuous thermal insulation body therewith.

In an embodiment the roof drain comprises a second reinforcement wall that extends around and spaced apart from the gutter wall, wherein the second reinforcement wall merges into the ring wall and crosses the first reinforcement walls, wherein the thermal insulation ring comprises a second accommodation slot that extends from the top surface, wherein the second reinforcement wall is accommodated in the second accommodation slot. The second reinforcement wall may provide a reinforcement along the entire circumference of the ring wall in addition to the reinforcement as provided by the first reinforcement walls.

In an embodiment the mounting shell comprises a shell mounting flange, wherein the ring wall forms or defines a funnel mounting flange of the bottom funnel that is mounted to the shell mounting flange. In this embodiment the mounting shell and the bottom funnel form different parts that are mounted to each other by means of the mounting flanges. The mounting shell and the bottom funnel can therefore be manufactured separately, whereby weak areas can be prevented. The first reinforcement walls prevent the shell mounting flange and the funnel mounting flange from deforming when the different parts are tightened together.

In an embodiment the bottom funnel flange comprises multiple screw bushes that merge into the ring wall and that project therefrom, wherein the thermal insulation ring comprises accommodation holes that extend from the top surface, wherein the screw bushes are accommodated in the accommodation holes.

In an embodiment thereof the screw bushes are located on crossings of the first reinforcement walls and the second reinforcement wall.

In an embodiment the shell mounting flange and the funnel mounting flange are mounted to each other with mounting screws that extend through the shell mounting flange into the screw bushes.

In an embodiment the thermal insulation ring is of a hard or form stable plastic foam, whereby it can be installed against the bottom funnel as one piece.

In an embodiment thereof the thermal insulation ring is of expanded polystyrene (PS) or polystyrene hard foam.

In an embodiment the roof drain furthermore comprises a valve body that is mounted to the mounting shell or to the bottom funnel, wherein the valve body comprises a bottom wall that extends inside the bottom funnel, above and spaced apart from the bottom spout. The 5 valve body preferably enables the roof drain to drain off the rain water at sub-atmospheric pressure in the rainwater tubing that is connected to the bottom spout, whereby a higher drain off capacity is reached when compared to draining off rainwater in a natural way. In the art this is called a siphonic roof drain system or an UV roof drain system.

In an embodiment thereof the valve body is of a plastic.

In a particular embodiment thereof the valve body is of polyethylene (PE) or polypropylene (PP).

In an embodiment the roof drain furthermore comprises a dirt grid that is mounted to the valve body and that extends over the bottom wall of the valve body to prevent obstruction of the bottom funnel.

In an embodiment thereof the dirt grid is of a plastic.

In a particular embodiment thereof the dirt grid is of polyethylene (PE) or polypropylene (PP).

In an embodiment the mounting shell is of a material that differs {from the material of the bottom funnel, whereby for each of these parts a suitable material can be applied.

In an embodiment thereof the mounting shell is of a metal, preferably a metal sheet, whereby a watertight top layer of the roof construction, such as an EPDM roof foil or a bituminous layer, can be adhered to the mounting shell in a watertight manner.

In a particular embodiment thereof the mounting shell is of aluminum or stainless steel.

In an alternative embodiment the mounting shell is of a plastic.

In an embodiment thereof the mounting shell is of polyethylene (PE) or polypropylene (PP).

In an embodiment the bottom funnel is of a plastic, whereby it can be manufactured as one piece by injection molding for example.

In an embodiment thereof the bottom funnel is a thermoplastic polymer.

In a specific embodiment the bottom funnel is of a plastic selected from polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polycarbonate (PC) Oor blends thereof, preferably polycarbonate-acrylonitrile- butadieen-styreen (PC-ABS) or polycarbonate-acrylonitrile- styrene-acrylate {PC-ASA). The use of polycarbonate- acrylonitrile-butadieen-styreen (PC-ABS) blends or polycarbonate-acrylonitrile-styrene-acrylate (PC-ASA) blends for the bottom funnel is preferred in order to achieve improved fire and UV resistance. The fire resistance is desired as it has been found that in particular during mounting on roofs having a bituminous top layer, the funnel may otherwise become damaged by the heat applied to melt the bituminous top layer to the mounting shell.

In particular embodiments, the mounting shell is of a metal and the bottom funnel is of a plastic.

The various aspects and features described and shown in the specification can be applied, individually, wherever possible. These individual aspects, in particular the aspects and features described in the attached dependent claims, can be made subject of divisional patent applications.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be elucidated on the basis of an exemplary embodiment shown in the attached drawings, in which: Figures 1A and 1B are an isometric top view and a

: cross sectional view of a horizontal roof construction in which a roof drain system with a roof drain according to a first embodiment of the invention is installed; Figure 2 is a cross sectional view of the roof drain as shown in figures 1A and 1B; Figure 3 is an exploded top view of the roof drain as shown in figures 1A and 1B; Figure 4 is a bottom view of two components of the roof drain as shown in the exploded view of figure 3; Figures 5A and 5B are an isometric top view and a cross section of a horizontal roof construction in which a roof drain system with a roof drain according to a second embodiment of the invention is installed; Figure 6 is an exploded top view of the roof drain as shown in figures 5A and 5B; and Figure 7 is a partial exploded top view of the roof drain as shown in figures 5A and 5B;

DETAILED DESCRIPTION OF THE INVENTION Figures 1A and 1B show a horizontal roof construction 1 comprising multiple steel girders 2 that extend horizontal and parallel to each other to support a rigid roof bottom layer 3. The roof bottom layer 3 is formed with flat metal sheets or profiled metal sheets, such as trapezoidal sheets. The roof construction 1 comprises a thermal insulation layer 6 that is supported by the bottom layer 3. The thermal insulation layer 6 is typically made of a hard or form stable plastic foam, such as expanded polystyrene (PS) or polystyrene hard foam or polyisocyanurate (PIR), having at its bottom side a shape that mates with the shape of the roof bottom layer 3. The thermal insulation layer 3 is covered with a watertight layer 8, in this example a watertight foil, such as EPDM roof foil. The rigidity of the thermal insulation layer 6 is generally sufficient to withstand some spot contact on the watertight foil 8, which may be caused by a person walking on the roof construction, or by an air conditioning unit that is installed on the roof construction. The roof construction 1 is provided with a roof drain system 20 according to a first embodiment of the invention to drain off rainwater from the roof construction

1. The roof drain system 20 comprises a partially embedded roof drain 30 with a main axis $8 that is connected with a rainwater tubing 22. In this example the rainwater tubing 22 comprises a horizontal tube 23 that is suspended from the steel girders 2 by means of brackets 25, and a bend 24 at the end thereof that is connected to the roof drain 30. As best shown in figures 2 and 3, the roof drain 30 comprises a stepwise flanged mounting shell 40. The mounting shell 40 comprises a flat support flange 41 with a circular outer edge 42. At the inner side the support flange 41 merges via a slantingly recessed support wall 44 into a circular flat ring wall 46 that extends parallel to the flat support flange 41 and that in this example forms a lower clamping flange. The mounting shell 40 is provided with screw bushes 48 on the lower clamping flange 46 that are regularly distributed around it and that project therefrom. The lower clamping flange 46 merges via a conical gutter wall 50 into a circular flat shell mounting flange 53 that is provided with multiple mounting holes 55 that are regularly distributed around it. The shell mounting flange 53 has a circular inner edge 57% that defines a bottom opening 58. As best shown in figure 3, the roof drain 30 comprises an upper clamping ring 60. The upper clamping ring 60 comprises a circular flat upper clamping flange 61 that merges into a slanting inner wall 62 having a circular inner edge 63 that defines an opening 65. The upper clamping flange 61 mates with the lower clamping flange 46 and is provided with mounting holes 64 that coincide with the screw bushes 48 of the mounting shell 40. The mounting shell 40 and the clamping ring 60 are in this example made of a metal, in particular a metal sheet, in particular an aluminum metal sheet. Alternatively these parts are made of a plastic by means of injection molding, for example polyethylene (PE) or polypropylene (PP).

As best shown in figure 3, the roof drain 30 comprises a flat upper roof seal ring 70 and a flat lower roof seal ring 75 that are in this example identical and that fit between the lower clamping flange 46 and the upper clamping flange 61. The roof seal rings 70, 75 are provided with multiple mounting holes 71, 76 that coincide with the screw bushes 48 of the mounting shell 40. The watertight layer 8 1s inserted between the roof seal rings 70, 75, and tightened under the upper clamping flange 61 by means of mounting screws 68 that are screwed into the screw bushes

48.

As shown in figures 1B, 2, 4 and 5, the roof drain 30 comprises a bottom funnel 80. The bottom funnel 80 comprises a flat ring wall 81 that extends parallel to the flat support flange 41 and that in this example forms a funnel mounting flange that mates with the shell mounting flange 53 and that extends parallel to the support flange

41. The bottom funnel 80 is provided with screw bushes 82 that debouche into the funnel mounting flange 81 and that coincide with the mounting holes 55 of the shell mounting flange 53. The funnel mounting flange 81 merges inwardly into a cylindrical gutter wall 83, wherein the funnel mounting flange 81 and the gutter wall 83 are in cross section under an angle of in this example 90 degrees. The gutter wall 83 merges inwardly into a bottom wall 85 that extends parallel to the funnel mounting flange 81. The bottom wall 85 inwardly merges via a conical funnel wall 89 into a bottom spout 86 that can be connected with the rainwater tubing 22. The bottom funnel 80 comprises multiple bayonet slots 87 in the gutter wall 83 that are regularly distributed around it.

As best shown in figure 4, the bottom funnel 80 comprises multiple radially extending flat first reinforcement walls 90 that are regularly distributed around the outer circumference of the gutter wall 83. The bottom funnel 80 comprises a cylindrical, circumferentially extending second reinforcement wall 88 at a constant distance to the gutter wall 83 that merges into the funnel mounting flange 81 and into the screw bushes 82 or the first reinforcement walls 90, wherein for each screw bush 82 one first reinforcement wall 90 and the second reinforcement wall 88 together form a reinforcing crossing. The first reinforcement walls 90 merge into the gutter wall 83, into the funnel mounting flange 81 and into the second reinforcement wall 88 or screw bush 82, and define air gaps 93 in between that are open towards the bottom spout 86 to provide a lightweight and form stable bottom funnel 80. Cutside the second reinforcement wall 88 the first reinforcement walls 90 have a straight outer edge 92 that extends obliquely onto the main axis S. The bottom funnel 80 is in this example of a plastic by means of injection molding, for example plastic selected {from polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polycarbonate (PC) or blends thereof, preferably polycarbonate-acrylonitrile-butadieen- styreen (PC-ABS) or polycarbonate-acrylonitrile-styrene- acrylate (PC-ASA).

The roof drain 30 comprises a circular flat bottom seal ring 77 that fits between the shell mounting flange 53 and the funnel mounting flange 81. The bottom seal ring 77 is provided with multiple mounting holes 78 that coincide with the screw bushes 82 of the bottom funnel

80. The mounting shell 40 is mounted to the bottom funnel 80 with the bottom seal ring 77 in between by means of mounting screws 47 that extend through the mounting holes 55, 78 into the screw bushes 82.

The roof drain 30 comprises a thermal insulation ring 94 that extends around and against the bottom funnel

80. The thermal insulation ring 94 comprises a straight top surface 98 that abuts the funnel mounting flange 81 inside the air gaps 93, and multiple radially extending first accommodation slots 97, a circumferentially extending second accommodation slot 96, and multiple cylindrical accommodation holes 95 on some of the crossings for tight insertion and accommodation of respectively the first reinforcement walls 90, the second reinforcement wall 88 and the screw bushes 82 of the bottom funnel 80. The thermal insulation ring 94 thereby practically entirely fills the air gaps 93 of the bottom funnel 80. The thermal insulation ring 94 has an circumferentially extending side surface 99 that extends obliquely to the center line S and that at the top side is located practically against the outer edge of the funnel mounting flange 81. The thermal insulation ring 94 is in this example made of a hard or form stable plastic foam, such as expanded polystyrene (PS) or polystyrene hard foam.

The roof drain 30 comprises an internal valve body 100. As best shown in figures 2, 3 and 4, the valve body 100 has a cylindrical wall 101 that merges at the lower side into a straight bottom wall 102 with air holes 104, and that at the upper side merges into a straight top wall 105 with a circular outer edge 106. The valve body 100 comprises multiple radially extending supports 110 that are regularly distributed around the valve body 101. The supports 110 merge into the cylindrical wall 101 and into the top wall 105, and project radially from the outer edge 106 of the top wall 105. The supports 110 merge at their ends into a cylindrical support wall 103 that thereby extends spaced apart from the outer edge 106. The air valve 100 comprises multiple connectors 111 having a hook 112 that fits inside the bayonet slots 87 to twist mount the air valve 100 onto the bottom funnel 80. When installed as shown in figures 1A, 1B and 2, the bottom wall 102 of the air valve 100 extends inside the bottom funnel 80 spaced apart from the bottom wall 85 of the bottom funnel 80. The cylindrical wall 101 of the air valve 100 extends parallel and spaced apart from the gutter wall 83 of the bottom funnel 80, and the top wall 105 of the air valve 100 extends above and spaced apart from the shell mounting flange 53 of the mounting shelve 40, wherein the separating distance is practically equal for these three spaces. The roof drain 30 comprises a hat shaped dirt grid 114 that is bayonet mounted to the support wall 103 and that extends over the valve body 100.

The valve body 100 and the dirt grid 114 are in this example made of a plastic by means of injection molding, for example polyethylene (PE) or polypropylene (PP).

As best shown in figure 1, the roof drain 30 is installed in the roof construction 1 by making a recess 10 in the thermal insulation layer 6 having dimensions such that the recessed support wall 44 of the mounting shell 40 fits inside it while the support flange 41 remains above the thermal insulation layer 6. In the roof bottom layer 3 a passage 4 is made for the bottom spout 86. The recess 10 is filled up with a compliant thermal insulation material 11, such as glass wool. The mounting shell 40 with the bottom funnel 80 mounted to it is inserted in the compliant thermal insulation material 11, wherein the bottom spout 86 passes through the insert opening 4. When the watertight foil 8 is installed, it is placed between the upper roof seal ring 70 and the lower roof seal ring 75, where after the upper clamping ring 60 is installed to the lower clamping flange 46 by means of the mounting screws 68.

The compliant thermal insulation material 11 enters in tight contact with the roof drain 30, and in particular the thermal insulation ring 94 ensures that there are hardly any air gaps around the bottom funnel 80. Thereby it is prevented that vapor condensates against the bottom funnel 80 and drips for example along the bottom spout 86 into the building.

The valve body 100 prevents that air is sucked into the roof drain system 20 above a predefined flow rate of rainwater into the roof drain 30. Below that threshold, rainwater is drained off in a natural way. After reaching that threshold, the rainwater is drained off at sub- atmospheric pressure, whereby a higher drain off capacity is reached when compared to draining off rainwater in a natural way. In the art this is called a siphonic roof drain system or an UV roof drain system.

Figures 5A and 5B show a horizontal roof construction 201 that is provided with a roof drain system 220 according to a second embodiment of the invention to drain off rainwater from the roof construction 201. Figures 6 and 7 show the roof drain system 220 separately. The parts that correspond with the roof construction 1 according to the first embodiment are provided with the same reference numbers. Only the deviating {features are hereafter discussed.

In this example the thermal insulation layer 3 is covered with a watertight layer 208, in this example a bituminous layer.

The roof drain 230 comprises a flanged mounting shell 240. The mounting shell 240 comprises a circular flat support flange 241 that at the inner side merges via a cylindrical gutter wall 250 directly into the circular flat shell mounting flange 53 to which the bottom funnel 80 is mounted.

The mounting shell 240 is in this example made of a metal, in particular a metal sheet, in particular an aluminum metal sheet. Alternatively the mounting shell 240 is made of a plastic by means of injection molding, for example polyethylene (PE) or polypropylene (PP).

As opposed to the first embodiment, the second embodiment does not have a clamping ring 60, an upper roof seal ring 70 and a lower roof seal ring 75 which is provided in the first embodiment to clamp the watertight foil. The bituminous layer 8 is adhered onto the entire support flange 241, for example by heating the bottom side thereof with a burner just before it is pressed against the support flange 241. In this way a watertight connection is obtained without a need for clamping foil between seal rings.

It is to be understood that the above description is included to illustrate the operation of the preferred embodiments and is not meant to limit the scope of the invention. From the above discussion, many variations will be apparent to one skilled in the art that would yet be encompassed by the scope of the present invention.

Claims

CONCLUSIONS

Roof drain comprising a mounting shell with a support flange for mounting the roof drain in a roof construction, and a bottom funnel with a bottom spout for receiving and draining water, the roof drain comprising an annular wall between the support flange and the bottom spout extending parallel to the support flange , and which merges inwardly into a gutter wall extending downwardly and at an angle to the ring wall, the ring wall and the gutter wall being concentric with respect to the bottom spout, the roof outlet comprising a plurality of first stiffening walls distributed around an outer side of the gutter wall and merging into the ring wall and into the gutter wall, the roof drain comprising a thermal insulation ring having an upper surface facing the ring wall and first receiving slots extending from the upper surface, the first reinforcement walls being received in the first receiving slots .

Roof drain according to claim 1, wherein the angle is 45-90 degrees.

A roof drain according to any one of the preceding claims, wherein the first reinforcing walls extend radially from the outside of the gutter wall.

4. Roof drain according to one of the preceding claims, wherein the first reinforcing walls are straight reinforcing walls.

A roof drain according to any one of the preceding claims, wherein the top surface of the thermal insulation ring abuts against the ring wall.

A roof drain according to any one of the preceding claims, wherein the thermal insulation ring forms a bottom surface of the roof drain.

7. Roof drain according to one of the preceding claims, comprising a second reinforcing wall extending around and at a distance from the gutter wall, the second reinforcing wall continuing into the annular wall and traversing the first reinforcing walls, the thermal insulation ring comprising a second receiving slot extending from the upper surface extends, the second reinforcement wall being received in the second receiving slot.

A roof drain according to any one of the preceding claims, wherein the mounting shell comprises a shell mounting flange, and wherein the annular wall forms or defines a funnel mounting flange that is attached to the shell mounting flange.

A roof drain according to claim 8, wherein the mounting shell comprises a plurality of bushings that merge into and protrude from the ring wall, the thermal insulation ring having receiving holes extending from the top surface, the bushings being received in the receiving holes.

10. Roof drain according to claims 7 and 9, wherein the screw bushes are located at intersections of the first reinforcing walls and the second reinforcing wall.

A roof drain according to claim 9 or 10, wherein the shell mounting flange and the funnel mounting flange are secured together with mounting screws extending through the shell mounting flange into the threaded sockets.

A roof drain according to any one of the preceding claims, wherein the thermal insulation ring is made of a hard or dimensionally stable plastic foam.

13. Roof drain according to claim 12, wherein the thermal insulation ring is made of expanded polystyrene (PS) or polystyrene rigid foam.

A roof drain according to any one of the preceding claims, further comprising a valve body attached to the mounting shell or to the bottom spout, the valve body comprising a bottom wall extending within the bottom funnel, above and spaced from the bottom spout.

15. Roof drain according to claim 14, wherein the valve body is made of a plastic.

16. Roof drain according to claim 15, wherein the valve body is made of polyethylene (PE) or polypropylene (PP).

A roof drain according to any one of claims 14-16, further comprising a dirt grid attached to the valve body and extending over the bottom wall of the valve body.

18. Roof drain according to claim 17, wherein the dirt grid is made of a plastic.

19. Roof drain according to claim 18, wherein the dirt grid is made of polyethylene (PE) or polypropylene (PP).

A roof drain according to any one of the preceding claims, wherein the mounting shell is of a material that differs from the material of the bottom funnel.

21. Roof drain according to one of the preceding claims, in which the mounting shell is made of a metal, preferably a metal plate.

22. Roof drain according to claim 21, wherein the mounting shell is made of aluminum or stainless steel.

23. Roof drain according to one of the preceding claims, in which the mounting shell is made of a plastic.

24. Roof drain according to claim 23, wherein the mounting shell is made of polyethylene (PE) or polypropylene (PP).

A roof drain according to any one of the preceding claims, wherein the bottom funnel is made of a plastic.

The roof drain of claim 25, wherein the bottom funnel is of a thermoplastic polymer.

27. Roof drain according to claim 25 or 26, wherein the bottom funnel is of a plastic selected from polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polycarbonate (PC) or mixtures thereof, preferably polycarbonate-acrylonitrile-butadiene -styrene (PC-ABS) or polycarbonate-acrylonitrile-styrene-acrylate (PC-ASA).

A roof drain according to any one of the preceding claims, wherein the mounting shell is made of a metal and the bottom funnel is made of a plastic.

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