EP2944731B1

EP2944731B1 - Chamber for a rainwater drain and method for its manufacturing

Info

Publication number: EP2944731B1
Application number: EP14167533.0A
Authority: EP
Inventors: Harri Ulmanen; Niclas Bolander; Jan-Olof Olofsson
Original assignee: Uponor Infra Oy
Current assignee: Uponor Infra Oy
Priority date: 2014-05-02
Filing date: 2014-05-08
Publication date: 2019-07-10
Anticipated expiration: 2034-05-08
Also published as: EP2944731A1; DK2944731T3

Description

The invention relates to a chamber for a rainwater drain with a bottom, an inlet for collecting rainwater and an outlet for routing the rainwater. The invention further relates to a method for manufacturing such a chamber.
Chambers for a rainwater drain are known from the art, for example from the German utility model DE 20107460 U1 . Such chambers are typically used on roadsides, parking lots, sealed surfaces or the like. These chambers are provided for collecting rainwater and leading it further below the earth's surface, in order to control the rainwater drain.
GB 1 363 302 A discloses a manhole for use in drainage systems.
GB 1 358 986 A discloses drainage traps.
GB 2 319 542 A discloses a prefabricated plastics road gully having an outlet socket projecting from the gully.
US 2005/0178721 A1 discloses a septic tank formed of a blow moulded body.
GB 2 145 444 A discloses manhole components moulded from a plastics material.
GB 2 097 030 A discloses a plastics gully and a method of manufacturing such gully.
GB 2 046 811 A discloses an inspection chamber and a method of manufacturing such chamber.
One object of the invention is to disclose a chamber and a method for its manufacturing, which facilitate a reliable and cost-saving production of the chamber.
According to a first aspect of the invention, a chamber for a rainwater drain is disclosed. The chamber comprises a main body with a bottom, an inlet for collecting rainwater and an outlet for routing the rainwater. The chamber is manufactured by blow moulding. The outlet comprises a cylindrical first pipe connection with a first outer diameter for a pipe to be attached to and a cylindrical second pipe connection with a second outer diameter for a pipe to be attached to, wherein the second pipe connection is adjacent to the first pipe connection and wherein the first diameter is larger than the second diameter. Rotational axes of symmetry of the first pipe connection and the second pipe connection are arranged parallel offset such that cross sections of both pipe connections touch each other in at least one bottom point, if the cross sections are projected in a plane that runs normally to both rotational axes of symmetry.
Due to the blow molding, the chamber is produced as one piece. This means that the chamber is manufactured in one single blow moulding cycle. Hence, manufacturing costs can be highly reduced compared to handmade chambers, e.g. by up to 50%. In contrast to handmade chambers, single parts of the chamber do not need to be joined in subsequent manufacturing steps, such as welding. Further, quality problems with regard to water tightness or tolerances are avoided or at least reduced.
Further, the chamber enables a constant flow channel without any gaps or flow obstacles. Furthermore, a chamber of high quality with regard to material usage and flow properties of the rainwater can be manufactured. Further, the chamber offers ease of inspection, in particular with regard to water leaks or the like.
In an embodiment, the main body of the chamber is at least partially cylindrical and the outlet extends in an essentially radial direction with regard to a central longitudinal axis of the main body. The inlet of the main body is typically opened in the direction of gravity. This makes it possible to conduct the rainwater via the outlet substantially parallel to the earth's surface.
In a further embodiment, an inner surface of the bottom of the main body is inclined and/or rounded towards a center of the main body and/or towards the outlet in direction of gravity. The bottom within the main body is inclined and/or rounded such that the bottom surface is funnel-shaped in a direction of gravity towards the center and/or the outlet. This guarantees that the rainwater can fully flow out of the chamber via the outlet. Further, no rainwater remains in the main body when it is not raining and no rainwater enters the main body via the inlet. Thus, the chamber can dry fast, for example, such that growing of bacteria is avoided or reduced.
In a further embodiment, a transition of a sidewall of the main body and the bottom of main body is rounded. Preferably, the transitions of every sidewall of the main body and the bottom are rounded. This ensures an even material distribution in the blow moulding process. This enables a constant wall thickness of the chamber. Further, flow properties of the rainwater within the chamber are improved.
In a further embodiment of the invention, the main body comprises, with regard to a central longitudinal axis, a first section with the inlet and a second section with the bottom and the outlet, wherein a cross-sectional area of the first section is larger than the second section. Preferably, a transition of the inner contour of the main body from the first section to the second section is rounded and/or funnel-shaped.
In a further embodiment, an outer end of the outlet lays within a projected cross section of the first section normally to a central longitudinal axis of the main body. Thus, a compact design of the chamber is achieved. In particular with regard to the blow molding process, such a design can be manufactured with an even material usage. Since the outlet does not exceed the main body in the radial direction, an even distribution of melted material during the blow moulding process is improved.
According to a second aspect of the invention a method for manufacturing a chamber according to the first aspect of the invention is described, wherein the method comprises blow moulding of the chamber. In particular, the chamber is produced in one blow moulding cycle.
The method for manufacturing the chamber substantially enables the aforementioned advantages.
Further embodiments of the invention are given in the dependent claims and the description of detailed embodiments.
Two exemplary embodiments of the invention are explained in the following with the aid of schematic drawings and reference numbers. Identical reference numbers designate elements or components with identical or similar functions.
The figures are as follows:

Figures 1 to 4: four views of a chamber according to a first embodiment of the invention,
Figure 5: a detailed side view of a pipe connection of the chamber
Figures 6 and 7: two views of a chamber according to a second embodiment of the invention and
Figure 8: a sequence diagram of a method for manufacturing a chamber.

Figures 1 to 4 show different views of a chamber 1, which is provided for a controlled rainwater drain. Figure 1 shows a perspective view, figures 2 and 3 show side views and figure 4 shows a top view of the chamber 1.
The chamber 1 is produced in one single blow moulding cycle and is made of a plastic material. The plastic material consists of polyethylene (PE). Alternatively other plastic materials like low density polyethylene (LD-PE), polypropylene (PP), polybutene (PB), temperature-resistant polyethylene (PERT) or others are suitable.
The chamber 1 has a main body 2, which is partially corrugated. The main body 2 has a bottom 3, an inlet 4 for collecting rainwater and an outlet 5 for disposal of the rainwater. The bottom 3 may also be called bottom part of the main body 2. The main body 2 is cylindrical around a central longitudinal axis 6. The central longitudinal axis 6 is a rotational axis of symmetry of the main body 2. The inlet 4 is an opening of the main body 2. The opening of the inlet 4 is limited by the cylindrical sidewall 7 of the main body 2. An inner diameter of the main body 2 is about 317 mm. An outer diameter of the main body 2 is about 350 mm.
The chamber 1 is buried on roadsides, in order to collect rainwater via the inlet 4 and dispose it via the outlet 5. Conventional chamber covers can be connected to the main body 2 covering the inlet 4, e.g. in a gully installation. Thus, the chamber 1 enables a controlled rainwater drain, wherein the rainwater is conducted essentially parallel to the earth's surface. Thereby, the chamber 1 is arranged such that the opening of the inlet 4 is opened against the direction of gravitational force. In other words, the central longitudinal axis 6 of the chamber 1 falls with the direction of gravity. Alternatively, the chamber 1 is buried at parking lots or other sealed surfaces, which are exposed to rain.
The outlet 5 essentially extends in a radial direction 8 (see figure 3) with regard to the central longitudinal axis 6. The outlet 5 has a first pipe connection 9 and a second pipe connection 10. The pipe connections 9 and 10 are adapted for a pipe to be attached by conventional means. The pipe connections 9 and 10 are subsequently arranged along the radial direction 8. Both pipe connections 9 and 10 are designed cylindrically, wherein a first diameter of the first pipe connection 9 is larger than a second diameter of the second pipe connection 10. The first diameter of the first pipe connection 9 may be 160 mm and the second diameter of the second pipe connection 10 may be 110 mm.
The second pipe connection 10 is opened such that a respective pipe can be attached or connected to the second pipe connection 10 in the field. Alternatively, the second pipe connection 10 is closed or sealed, in order to avoid dirt entering the chamber 1 during installation. Then, before connecting pipes thereto, the pipe connection 10 needs to be exposed or opened.
If a pipe having a respective diameter is connected to the first pipe connection 9, the second pipe connection 10 needs to be removed. In particular, the second pipe connection 10 needs to be cut off, e.g. by a saw or a crusher. In order to facilitate this, a groove 11 surrounds the circumference of the first pipe connection 9. The groove 11 is shown in figure 5, which shows an enlarged and detailed view of an area 21 of figure 4. Due to the groove 11, the first pipe connection 9 can easily be exposed. Alternatively, the groove 11 is formed as a notch or the like.
By providing at least two pipe connections, the chamber provides a universal connector. This allows a user to decide in the field during installation, whether to use a pipe with a diameter according to the first diameter of the first connection or a pipe with a diameter according to the second diameter of the second pipe connection.
The first pipe connection 9 has a first rotational axis of symmetry 12 and the second pipe connection 10 has a second rotational axis of symmetry 13. Both rotational axes of symmetry 12 and 13 are arranged parallelly offset and each form an angle of 1° with a plane 14 in the direction of gravity. The plane 14 runs normally to the central longitudinal axis 6. Due to the angle, rainwater entering the main body via the inlet 4 is to leave the main body via the outlet 5 due to gravitational force. Alternatively, the angle may be at least more the 0.5°. The parallel offset is chosen such that a cross section of the first pipe connection 9 and a cross section of the second pipe connection 10 touch each other in at least one bottom point 19, if the cross sections are projected in a plane, that runs normally to both the rotational axes of symmetry 12 or 13 (see Figure 2). Thus, a transition of the inner bottom from the first pipe connection 9 to the second pipe connection 10 is straight lined, such that the rainwater can leave the first pipe connection 9 into the second pipe connection 10 without any flow obstacles.
The sidewall 7 of the chamber 1 and the bottom 3 have transitions which are rounded and comprise two different radii 15. The radii 15 may be, for example, 40 and 80 mm. Due to the roundings, a distribution of material during the blow moulding process is improved. Also, good flow properties for the rainwater within the chamber 1 are achieved.
The inside of the chamber 1 is rounded and does not comprise any gaps or edges, which could form obstacles to the rainwater during its flow through the chamber 1. In general, the chamber 1 has a round form, in particular in the middle of the chamber 1, which gives stiffness to the chamber 1 and eases up anchoring of the chamber 1 during installation.
In particular, with respect to Figure 4, the outlet 5 has an inner opening area 16 facing an inside of the main body 2 (see hatched area). An inner surface of the bottom 3 is inclined and rounded towards the inner opening area 16 of the outlet, e.g. forming an angle α of 4° with egdes of the inner opening area 16. In particular, the bottom surface is rounded and inclined towards a center of the main body 2 in the direction of gravity. This has the effect that the bottom 3 within the main body 2 is funnel-shaped towards the inner opening area 16 and thus towards the outlet 5. This guarantees that the rainwater leaves the main body 2 via the outlet 5 without any leftover water within the main body 2. This makes it possible that the chamber 1 fully and quickly dries, when there is no rainwater entering the main body 2 via the inlet 4.
Figures 6 and 7 show two views of a chamber 1 according to a second embodiment. The depicted chamber 1 essentially has the same features as described above with regard to figures 1 to 5, with the exception that the main body 2 is separated in a corrugated first section 17 and a second section 18.
The cylindrical sidewall 7 of the first section 17 is formed around the central longitudinal axis 6. A cross-sectional area of the first section 17 is larger than a cross-sectional area of the second section 18. The second section 18 is arranged decentrally with regard to the central longitudinal axis 6. Further, the second section 18 does not exceed the first section 17 in the radial direction 8. Hence, an outer end 20 of the outlet 5 lays within the projected cross section of the first section 17 along the axis 6. A transition of an inner contour of the main body from the first section 17 to the second section 18 is rounded and/or funnel-shaped. This guarantees substantially the same advantages with regard to flow properties, as described above.
Due to the compact design of the chamber 1 by not having any part exceeding the imaginary cylindrical in radial direction, the blow moulding process is improved. For example, a material distribution during the blow moulding process is improved. For example, a wall thickness of the chamber 1 is even.
Figure 8 shows a sequence diagram of a method M for manufacturing a chamber 1 according to the embodiments described with the aid of figures 1 to 7.
The method M describes one cycle of a blow moulding process, in particular an extrusion blow moulding process.
In a step S1, a plastic material is melted down. The material may comprise one of the aforementioned materials. In a next step S2, the melted plastic is formed into a parison. In a next step S3, the parison is clamped into a mould, which consists at least of two parts. The mould can also be named forming tool. The mould consists of two parts, each representing a negative contour of half of the chamber 1. In a next step S4, compressed air is pressured into the parison. Due to the compressed air the parison is pressed against the mould in order to match it and to form the chamber 1. In a next step S5, the blow molded chamber 1 within the mould is cooled. In a next step S6, the two-part mould is opened such that the blow moulded chamber 1 is ejected.
If there are high requirements regarding tolerances of the chamber 1, in particular tolerances of the outlet 5, the chamber 1 is finished by turning, polishing or other machining processes in an optional step. In particular, the first pipe connection 9 and the second pipe connection 10 may need exact dimensions, in order that pipes can be attached to the chamber 1. Thus, these connections 9 and 10 are finished such that a secure and watertight connection to an adjoining pipe is enabled.
Alternatively or optionally, the mould is designed such that dimensions and/or diameters of the chamber 1 are larger than intended for use. For example, a diameter of the two part-mould corresponding to the main body 2 or the first section 17 may be larger. This allows to blow mould all parts of the chamber 1, especially the outlet 5 of the chamber 1 according to the first embodiment with its pipe connections 9 and 10. Thus, a sufficient wall thickness and/or even material usage of all parts of chamber 1 is achieved. This means that there may be left some extra or excess material of the chamber 1, in particular with regard to the corrugated parts of the chamber 1, the main body 2 and/or the first section 17. This excess material, for example flash, can be removed later in a subsequent step in particular by one or several machining processes. Thus, the chamber 1 is finished into its intended form. For example, the intended diameters and/or the outlet 5 can be carved out.
Alternatively, the two-part mould may designed such that the chamber 1 does not need to be finished. Then for example, a diameter of the two-part mould corresponding to the main body 2 or the first section 17 may be identical to the intended diameter of the main body 2 of the chamber 1.
The described method M defines one blow moulding cycle, such that the chamber 1 is blow moulded in one cycle. The chamber 1 has no parts in the inside, such that blow moulding of the chamber 1 is enabled.
In an alternative not-shown method, the chamber 1 is blow molded of a preform, for example a preform in shape of a sock. In this case, instead of blow moulding a parison according to step S3 as described above, the preform is put in a mould and is blow moulded therein by compressed air, in order to produce the chamber 1. In other words, the chamber 1 is blow moulded of the preform. The preform has larger dimensions and/or diameters than the chamber 1, especially than the corrugated part of the main body 2 or the first section 17. In other words, the preform is oversized when the blow molding process starts. Due to this oversized preform, the outlet 5 of the chamber 1 can be blow molded, wherein a sufficiently thick wall thickness of the outlet 5, in particular the first and second pipe connection 9 and 10, is achieved. Again, there may be left some extra or excess material of the chamber 1, in particular with regard to the corrugated parts of the chamber 1, the main body 2 and/or the first section 17. This excess material, for example flash, can be removed later in a subsequent step in particular by one or several machining processes. Thus, the chamber 1 is finished into its intended form. For example, the intended diameters and/or the outlet 5 can be carved out.
The preform may be produced in one or several steps before blow molding of the chamber 1. Thereby, the preform is produced by injection molding. Other alternatives in producing the preform are suitable, for example a further, previous blow molding process.
The described blow moulding processes can vary and is not limited to the described embodiment. Alternatively, if suitable, injection blow moulding processes or injection stretch blow moulding processes are also possible.
In an alternative embodiment not shown in the figures, the chamber according to the figures 1 to 7 may comprise a collector, which extends along the central longitudinal axis 6 in the direction of gravity below the outlet 5. The collector collects dirt like sand, stones or the like, since these elements sink into the collector due to the gravitational force. The collector avoids clogging of the outlet 5 and its pipe connections.

Reference Signs

1: chamber
2: main body
3: bottom
4: inlet
5: outlet
6: central longitudinal axis
7: sidewall
8: radial direction
9: first pipe connection
10: second pipe connection
11: groove
12: first rotational axis of symmetry
13: second rotational axis of symmetry
14: plane
15: radius
16: inner opening area
17: first section
18: second section
19: bottom point
20: outer end
21: area
α: angle
M: Method

Claims

Chamber (1) for a rainwater drain,
comprising a main body (2) with a bottom (3), an inlet (4) for collecting rainwater and an outlet (5) for routing the rainwater, wherein the chamber (1) is manufactured by blow moulding,
wherein:
- the outlet (5) comprises a cylindrical first pipe connection (9) with a first outer diameter for a pipe to be attached to and a cylindrical second pipe connection (10) with a second outer diameter for a pipe to be attached to, wherein the second pipe connection (10) is adjacent to the first pipe connection (9) and wherein the first diameter is larger than the second diameter, and

- rotational axes of symmetry (12, 13) of the first pipe connection (9) and the second pipe connection (10) are arranged parallel offset characterized in that the offset is such that cross sections of both pipe connections (9, 10) touch each other in at least one bottom point (19), if the cross sections are projected in a plane that runs normally to both rotational axes of symmetry (12, 13).
Chamber (1) according to claim 1, wherein the main body (2) is at least partially cylindrical and wherein the outlet (5) extends in an essentially radial direction (8) with regard to a central longitudinal axis (6) of the main body (2).
Chamber (1) according to any of the preceding claims, wherein an inner surface of the bottom (3) is inclined and/or rounded towards a center of the main body (2) and/or towards the outlet (5) in direction of gravity.
Chamber (1) according to any of the preceding claims, wherein a transition of a sidewall (7) of the main body (2) and the bottom (3) of the main body (2) is rounded.
Chamber (1) according to any of the preceding claims, wherein the main body (2) comprises with regard to a central longitudinal axis (6) a first section (17) with the inlet (4) and a second section (18) with the bottom and the outlet, wherein a largest cross sectional area of the first section (17) is larger than a largest cross sectional area of the second section (18).
Chamber (1) according to claim 5, wherein a transition of an inner contour of the main body (2) from the first section (17) to the second section (18) is rounded and/or funnel-shaped.
Chamber (1) according to claim 5 or 6, wherein an outer end of the outlet (5) lays within a projected, largest cross section of the first section (17) normally to a central longitudinal axis (6) of the main body (2).
Chamber (1) according any of the preceding claims, wherein the first pipe connection (9) and/or the second pipe connection (10) comprise a rotational axes (12, 13) of symmetry, which form an angle of more than 0.5° with a plane (14) in the direction of gravity, wherein the plane (14) runs normally to a central longitudinal axis (6) of the main body (2).
Chamber (1) according to any of the preceding claims, wherein the first pipe connection (9) comprises a groove (11), in particular a notch, forming a cutting mark, the groove (11) at least partially surrounding the outer circumference of the first pipe connection (9).
Method (M) for manufacturing a chamber (1) according to one of the preceding claims, comprising blow moulding of the chamber (1).
Method (M) according to claim 10, wherein a blow moulded chamber (1) is finished by a machining process.
Method (M) according to claim 10 or 11, wherein the chamber (1) is blow moulded of a preform.
Method (M) according to one of the claims 10 to 12, wherein excess material of a blow molded chamber (1) is removed.