|
(11) | EP 1 357 231 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
|
|
|
|
|||||||||||||||||||||||
| (54) | Grating and a frame for a grating |
| (57) The invention relates to a rainwater grating which comprises a frame (1) and a grate
(2) settled on the frame, the frame comprising a flow-through opening (4) and a flange
(6) circumferentially surrounding the flow-through opening, the flange having a top
end (9), bottom end (10), outer rim (7) and inner rim (8). To achieve a better than
normal water receptivity for the rainwater grating, the flange (6) comprises at least
one rainwater groove (11) arranged to guide water arriving at the top end (9) of the
flange through openings (17 to 19) of the grate (2) to the flow-through opening (4)
of the frame. |
BACKGROUND OF THE INVENTION
[0001] The invention relates to a grating which comprises a frame and a grate settled on the frame, the frame comprising a flow-through opening and a flange circumferentially surrounding the flow-through opening, the flange having a top end, bottom end, outer rim and inner rim. The invention also relates to a grating frame according to the preamble of the attached claim 15. The grating can also be called a rainwater grating.
[0002] This type of grating is well known. It is typically used on roadways in urban areas to guide rainwater falling on the roadways to the grating. It is also used on the walk and drive surfaces of squares and courtyards. So as to efficiently guide water accumulating on the drive surface away from it, the grating is installed at a level that is lower than the level of the surrounding area. Due to what is stated above, gratings are very often installed on the roadway close to the edge of the pavement, because the roadway usually slopes towards the pavement.
[0003] Even a small installation error may cause the flange to remain too high, thus preventing water from entering the gully.
[0004] When conventional gratings comprising a planar top surface are installed close to the edge of the pavement, the outer rim of the grating flange settles, perforce, in practice, at a distance from the edge of the pavement. This is due to the fact that the pavement prevents the installation of the grating right next to the edge of the pavement. When the roadway slopes towards the pavement, rainwater flows against the edge of the pavement, and if the road is not horizontal, rainwater flows along the edge of the pavement past the grating. This problem naturally results in that another grating positioned lower along the road is overloaded and cannot suck in the large amount of water. This situation causes a flood. Alternatively, a large amount of water may, owing to the slope of the road, be directed to a point where water should not flow.
[0005] To solve the above-mentioned problem, a step-shaped grating is known that is installed partly on the pavement and partly on the roadway, whereby the grate of the grating settles at a point that corresponds to the edge of the pavement. Even though this known step-shaped grating is well suited for certain installations, its complex structure constitutes a problem, its installation requires difficult work stages and, in addition, it is naturally not suitable for installation in locations where the surrounding area is planar.
[0006] Thus, a problem with the prior-art gratings is that they - at least in respect of their size - cannot efficiently guide rainwater to the flow-through opening of the frame when the grating is installed in the conventional horizontal position. Theoretically thinking, by installing the prior-art gratings in such a manner that their top surface is below the drive/walk surface, it is possible to improve their ability to guide water into the flow-through opening, but gratings installed in this manner provide a poor and at the same time dangerous walk/drive surface.
BRIEF DESCRIPTION OF THE INVENTION
[0007] It is thus an object of the invention to provide a novel grating that eliminates the above-mentioned problems and is thus capable of efficiently guiding rainwater into the flow-through opening of the frame when the grating is installed horizontally at the height of the walk surface / roadway. To achieve this, the grating of the invention is characterized in that its flange comprises at least one rainwater groove arranged to guide water arriving at the top end of the flange to the flow-through opening of the frame. Said at least one groove serves as a water-guiding groove in a grating that is installed fully horizontal, for instance.
[0008] Owing to the fact that the grating flange comprises one or typically several rainwater grooves, the flange of a grating installed close to the pavement and level with it is capable of guiding rainwater away from the area where, when the prior-art gratings are used, water is guided along the flange past the grating. Considering that, as a rule, the flange is quite wide in so-called floating gratings (because the flange is used as the bearing surface of the grating), the surface area of the flange is also large (typically as large as the surface area of the perforated grate of the grating), it can be understood that the flange of the grating of the invention is capable of guiding a considerable amount of water to the flow-through opening of the grating.
[0009] The groove is preferably at a 2- to 20-degree angle to the plane defined by the flange. If the angle is too big, the frame and grate of the grating become, perforce, cumbersome. Too small an angle cannot provide an efficient water flow. The bottom of the groove does not need to be at the same angle along its entire length, but the angle can vary along the length of the groove. Naturally, the aim is to give the bottom of the groove such a shape that the groove can as efficiently as possible guide water to the flow-through opening of the frame.
[0010] Most preferably, between the rainwater grooves, there are substantially horizontal ridges that are arranged to form a drive/walk surface, on which it is possible to walk or drive with a vehicle without problems. The width of the rainwater grooves is then preferably 5 to 40 mm and the width of the ridges is at least 5 mm so as to provide good support for pedestrians and vehicle tyres. The width of the rainwater grooves can advantageously narrow as seen from the outer rim of the flange to the inner rim, i.e. in the direction, in which the rainwater grooves deepen. For conventional applications, the width of the rainwater grooves is 10 to 20 mm.
[0011] The grating flange is preferably circular, because a circular grating is usually easy to install on the road surface. If the road is paved with stone blocks or tiles, flanges having other shapes, for instance squares, can preferably be used.
[0012] For rainwater to flow efficiently to from the flange to the flow-through opening of the frame, the grate preferably comprises a groove or grooves corresponding to the groove or grooves of the flange on its outer rim. The top plane of the grate also preferably comprises ridges that form a suitable drive and walk surface. The width of the ridges corresponds to the width of the ridges of the flange.
[0013] Preferred embodiments of the grating of the invention are described in the attached claims 2 to 15.
[0014] The grating frame of the invention is characterized by what is stated in the characterizing part of the attached claim 16. Preferable features of the frame are the same as those of the grating, i.e. as stated in the attached claims 2 to 10.
[0015] The biggest advantages provided by the grating and grating frame of the invention are that the water receptivity of the grating becomes significantly better than in a conventional grating. At the same time, the danger of blockage of the grating, due to leaves, for example, is reduced. The top plane of the grating can be installed on the same plane as, i.e. level with, the walk/drive surface without weakening the operation of the grating. Due to what is stated above, the grating of the invention provides a vehicle an even surface (that does not shake the car) and a person an even walk surface. The grating works without problems even when its installation is not quite exact.
BRIEF DESCRIPTION OF THE FIGURES
[0016] The invention will now be described by means of one preferred embodiment with reference to the attached drawing, in which
Figure 1 is a top view of the grating,
Figure 2 is a view of the grating cut along the line II-II of Figure 1,
Figure 3 is a perspective view of the frame of the grating in Figure 1, and
Figure 4 is a perspective view of the grate of the grating in Figure 1.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The figure shows that the frame 1 comprises a cylindrical part 3 with a central flow-through opening 4 inside it. The inner surface of the cylindrical part 3 has a shoulder 5 and the grate 2 supports on the top surface of the shoulder. The top end of the cylindrical part 3 has a flange 6. The flange 6 comprises an outer rim 7, inner rim 8, top end 9 and bottom end 10. The surface area of the bottom end 10 of the flange 6 serves as a bearing surface for the grating, which is a floating grating, so the flange 6 should be sufficiently big. The width of the flange 6 (i.e. the distance between the outer rim and inner rim of the flange) is typically 50 to 120 mm.
[0019] Figures 1 and 2 show that the flange 6 of the frame 1 has several rainwater grooves 11 (42 in total) that extend radially from the outer rim 7 of the flange to the inner rim 8 of the flange. The grooves preferably start at a distance of 0 to 15 mm from the outer rim 7 of the flange and are arranged to provide unobstructed flow for water. If the grooves start at a great distance, for instance 30 mm, from the outer rim 7, the ability of the grooves to guide water is poor, which is contrary to the aims of the invention. The grooves 11 extend to the inner rim 8 of the frame.
[0020] The bottom 12 of the grooves 11 is at an angle α = approximately 5 degrees to the plane defined by the flange, i.e. the top surface of the flange. The size of the angle α may preferably vary within the range of 2 to 10 degrees. The angle α can be smaller than 2 degrees, but when the angle is very small, the ability of the groove 11 to guide water towards the flow-through opening 4 becomes poorer; the minimum value for the angle α is assumed to be approximately 1 degree. The angle α can be bigger than 10 degrees, but then the grating becomes cumbersome: the flange and grate would become unreasonably thick. Due to what is stated above, the top limit of the angle α is approximately 20 degrees in practice.
[0021] The width L of the grooves 11 in the flange 6 is 5 to 20 mm depending on the size of the grating, for instance. A width of approximately 10 to 40 mm is suitable for nearly all applications and a width of 10 to 30 mm is suitable for most applications. A typical number of grooves 11 is 10 to 60 depending on the size of the grating. If the number of grooves 11 is small, for instance 2 to 5, the grooves should be very wide so as to efficiently transport water to the flow-through opening 4. However, wide grooves make it impossible to form an even drive and walk surface; they may also cause difficulties for bicycle traffic. Due to what is stated above, the number of grooves 11 can in practice be small only if the grooves are centred at a specific point/area of the flange 6 and the grating is installed in a location where water from the surrounding area naturally flows on the grooves of the grating. A location of this type is typically found close to the edge of the pavement, in which case the grooves are installed to point towards the edge of the pavement.
[0022] Figures 1 and 2 show that the grate 2 also comprises several grooves 13 (14 in total). The number of grooves 13 in the grate is smaller, because one groove is arranged to receive water flowing from three of the flange 6 grooves 11. The grooves 13 start from the outer rim 20 of the grate 2 in such a manner that the bottoms 14 of the grooves are level or almost level with the bottoms 12 of the flange grooves 11 on the inner rim 8 of the flange. The grooves 13 are directed radially towards the flow-through opening 4 and the bottoms 14 of the grooves are, in the example of the figure, at the same angle as the grooves 11. The size of the angle of the bottom 14 of the grooves 13 may preferably vary within the range of 0 to 50 degrees, an angle of 2 to 30 degrees being the most preferable. When the angle of the bottom of the groove 13 of the grate is 0, the bottom does not slope, in which case the bottom must settle sufficiently low so as not to form a disadvantageous obstruction for the flow of water from the grooves 11. The slope of the bottoms of the grooves 13 naturally improves flow, i.e. the guiding of water to the flow-through opening 4. The angle preferably increases towards the flow-through opening 4. This way, the grooves 13 can be at a very slight angle and even horizontal, because the water in the grooves 11 pushes the water in the grooves 13 to the flow-through opening 4. An angle of at least 2 degrees is, however, preferable, because then water does not remain at the bottom 14 of the grooves 13. If the bottom 14 of the grooves 13 is at too big an angle relative to the top surface of the grate, the frame of the grate 2 becomes cumbersome, because it is necessary to have a bearing surface in the grate to rest against the shoulder 5. As seen radially along the groove 13, the bottom 14 is preferably rounded, because this improves the flow of water.
[0023] The grooves 13 on the grate are made to narrow towards the flow-through opening 4. The width of the grooves 13 is approximately 2 to 4 times the width of the grooves 11 in the flange. The width of the grooves 13 should not exceed 30 to 40 mm so as to avoid gaps in the walk surface that hamper walking. The bigger the grate 1 is, the larger the number of grooves 13 it typically has.
[0024] Between the flange grooves 11 of the frame, there are ridges 15, which can also be called bridges. The top surface of the ridges 15 is horizontal or substantially horizontal, whereby sufficiently close together positioned ridges form a drive or walk surface. For the ridges 15 to work well as a walk surface, the width S of the ridges is at least 5 mm, typically 10 to 15 mm, and the width L of the grooves 11 between the ridges is 5 to 20 mm.
[0025] There are ridges 16 or bridges also between the grooves 13 of the grate 2. The top surface of the ridges 16 is substantially level with the top surfaces of the flange ridges 14. The width of the top surface of the ridges 16, i.e. the thickness of the ridges, is at least approximately 5 mm, typically 10 to 15 mm.
[0026] Reference numerals 17, 18 and 19 indicate openings formed in the grate 2, from which water is guided to the flow-through opening 4.
[0029] In the above, the invention is described by means of only one example and, therefore, it should be noted that the invention may vary in detail in many ways within the scope of the attached claims. Thus, the flow-through opening does not necessarily need to be positioned symmetrically and the grating does not necessarily need to be round; it can for instance be rectangular in shape. A round shape is, however, usually most preferable for the installation of the grating. The number of rainwater grooves 11 may vary: typically, there are several grooves, but in theory, even one groove may help water flow from the flange to the flow-through opening. A small number of grooves does, however, cause the above-mentioned problems (i.e. restrictions on the use of the grating, and the flange needs to be installed in a specific direction, and/or the flange is not a good drive and walk surface). The bottoms of the grooves 11, 13 need naturally not be straight, even though a substantially straight shape is preferable for manufacturing. Therefore, the slope of the bottom of the rainwater groove 11 may change along the length of the groove. The flange grooves need not start exactly at the outer rim 7 of the flange, even though in practice, the aim is to position the starting point of the grooves as close as possible to the outer rim, because the water receptivity of the flange is then at its best. The grating does not need to have grooves on its entire top surface, but part of the top surface of the grating, and preferably part of the flange, for example 10 to 30 and even 50 degrees of the circular grating circumference, can be without grooves. In the latter case, the flange of the grate has a largish even surface for text, letters, patterns, etc. If the even section is large, it is preferably divided into several parts. The flow-through opening 4 does not necessarily need to be positioned centrally to the grating or its frame.
1. A grating which comprises a frame (1) and a grate (2) settled on the frame, the frame
comprising a flow-through opening (4) and a flange (6) circumferentially surrounding
the flow-through opening, the flange having a top end (9), bottom end (10), outer
rim (7) and inner rim (8), characterized in that the flange (6) comprises at least one rainwater groove (11) arranged to guide water
arriving at the top end (9) of the flange to the flow-through opening (4) of the frame.
2. A grating as claimed in claim 1, characterized in that the bottom (12) of said at least one rainwater groove (11) is at an angle (α) of
1 to 20 degrees with respect to the plane of the flange (6).
3. A grating as claimed in claim 2, characterized in that the bottom (12) of said at least one rainwater groove (11) is at an angle (α) of
2 to 10 degrees with respect to the plane of the flange (6).
4. A grating as claimed in any one of the preceding claims, characterized in that the flange (6) comprises several rainwater grooves (11).
5. A grating as claimed in claim 4, characterized in that the number of rainwater grooves (11) is 10 to 60.
6. A grating as claimed in claim 4 or 5, characterized in that the rainwater grooves (11) extend at least approximately radially from the outer
rim (7) of the flange towards the inner rim (8) of the flange.
7. A grating as claimed in claim 6, characterized in that the rainwater grooves (11) begin at a distance of 0 to 15 mm from the outer rim (7)
of the flange (6).
8. A grating as claimed in any one of the preceding claims, characterized in that between the rainwater grooves (11), there are substantially horizontal ridges (15)
that form a walk and drive surface.
9. A grating as claimed in claim 8, characterized in that the width (L) of the rainwater grooves (11) is 5 to 40 mm and that the width (S)
of the ridges (15) between the rainwater grooves is at least 5 mm.
10. A grating as claimed in claim 4, characterized in that most of the rim area of the flange (6) in the area between the outer rim (7) and
inner rim (8) comprises said rainwater grooves (11).
11. A grating as claimed in any one of the preceding claims, characterized in that the grate (2) comprises at least one channel (13) that is arranged to receive and
guide water from the rainwater groove (11) of the flange to the flow-through opening
(4) of the frame, for which the bottom of the end of the channel towards the flange
(6) of the grate is arranged to be level with or lower than the bottom of the end
of the rainwater groove (11) of the flange towards the grate.
12. A grating as claimed in claim 11, characterized in that the flange (6) comprises several rainwater grooves (11) and that the grate (2) comprises
several channels (13) that are arranged to receive water from the rainwater grooves
of the flange and to guide the water to the flow-through opening (4) of the frame.
13. A grating as claimed in claim 12, characterized in that the channels of the grate are in the form of grooves (13), that between the rainwater
grooves (11) of the flange, there are substantially horizontal ridges (15) and that
between the grooves (13) of the grate (2), there are substantially horizontal ridges
(16) that are substantially level with the ridges (15) of the flange and form a walk
and drive surface.
14. A grating as claimed in claim 13, characterized in that the end of the channel (13) on the grate towards the flange (6) is below the walk
and drive surface formed by the ridges (16).
15. A grating as claimed in any one of the preceding claims, characterized in that the flange (6) is circular.
16. A grating frame (1) which comprises an flow-through opening (4) and a flange (6) circumferentially
surrounding the flow-through opening, the flange having a top end (9), bottom end
(10), outer rim (7) and inner rim (8), characterized in that the flange (6) comprises at least one rainwater groove (11) arranged to guide water
from the top end (9) of the flange to the flow-through opening (4) of the frame.