GB2106156A - Gutter system - Google Patents

Abstract

The capacity of a gutter system is improved by adapting the outlet to provide for an increased rate of flow from the gutter into the downpipe. A gutter outlet has gutter connecting portions 3 and a downpipe connecting portion 2. The throat portion 6 has a radius of curvature substantially greater than 1 DIVIDED 2 inch (12.5 mm), preferably it is about 2 inch (51 mm). Ribs 9 aid the directional flow of water through the outlet. <IMAGE>

Description

SPECIFICATION Gutter systems The present invention relates to gutter systems. More particularly it relates to outlets for gutter systems.

Such outlets may be known as running outlets where the outlet is situated midway of a length of gutter, or stop-end outlets where the outlet is situated at the end of a length of gutter. A stop-end outlet may be formed with an integral end plate or be made up from a running outlet and an end plate fitting for attachment thereto.

A gutter system will comprise a length of gutter for receiving rainfall from a roof and a number of downpipes for carrying the water to ground, connected to the gutter via outlets. The provision of a downpipe is a considerable expense, not only because of the required material and fixing, but also because of the need for an associated gully or soakaway to run the water into ground or the sewer etc.

A gutter system is designed so that its capacity will meet the maximum anticipated rainfall that is likely to occur, apart from during abnormal conditions. This can be predicted from a knowledge of local climate, direction of rainfall, roof dimensions and slope and the direction in which a roof faces etc. In the British Isles, for example, a maximum rainfall intensity of 75 mm/hour is normally used to calculate designs of gutter systems.

When a gutter system is overloaded it is found to over-flow in a region between downpipes, or between a down pipe and an end of the gutter. It can be seen that in a length of gutter having a downpipe at one end there will be a build up of water in a central portion because, whilst an end of the gutter distal of the downpipe receives only water directly from a roof area, a central portion of the gutter will receive water from a roof area and also water travelling along the gutter to the downpipe, and at downpipe end water is run away to ground.

It has long been considered that in a gutter system the maximum capacity is dictated by the size of the gutter - by its cross-sectional area and shape.

Hence, the flow capacity of a length of gutter of particular cross-section is determined, at say 100 litres per minute, and the expected flow load per metre of gutter or eave will be determined, at say 10 litres per minute, and hence the required frequency of downpipes, in the case given one in the middle of a 20 metre length, is determined.

The capacity of a gutter system can be increased by mounting the gutter on a slope, of say 1 in 600, or by increasing the frequency of downpipes in the system. The former method has the disadvantage that it tends to look unsightly when compared with the lines of a building, and the latter involves extra expense.

In order to reduce the required number of downpipes per length of gutter the cross-sectional area of the gutter is increased. In a typical gutter system it is generally found that the capacity of the downflow pipe is much greater than that of its associated length of gutter, say 500 litres per minute compared to 200 litres per minute for the length of gutter.

Considerable investigation has been made into the cross-sectional shape and area of gutter to optimise the capacity, bearing in mind the constraints of gutter strength, weight, volume of material required, aesthetic appeal etc. Examples are the half-round gutter having a semi - or near semi-circular cross-section, the rectilinear which provides for higher capacity than a half-round of the same width and depth by providing a greater cross-sectional area, and the elliptical or deep-flow which forms the subject of British Patent Specification No. 1,105,069.

In the past, little attention has been paid to the design of running outlets, other than to provide a simple and easily made junction between a gutter and a downpipe.

It has now been unexpectedly realised that a further limiting factor on the rating or capacity of a gutter system is the rate of flow of water into the downpipe. By paying special attention to the design of the outlet it has been found that the capacity of a system may be increased whilst retaining a constant cross-sectional area for the gutter. This provides for the up-rating of known systems and hence fewer down pipes and/or gutter of a smaller cross-sectional area may be used.

Accordingly, a first aspect of the present invention provides a method of improving the capacity of a gutter system comprising a gutter downpipe and an outlet, which method comprises adapting the outlet to provide for an increased rate of flow from the gutter into the downpipe.

It has been found that provisions for creating swirling at the junction between the gutter and the downpipe and off-setting the downpipe each provide an improvement in the capacity. Also sharply increasing the slope of the gutter in the region of the junction provides an improvement, but may require an outlet fitting of large size incorporating sloping gutter portions, and of limited aesthetic appeal.

Accordingly, a second aspect of the present invention provides an outlet for a gutter system, which outlet comprises a gutter connecting portion, a downpipe connecting portion and a throat portion wherein, in a plane containing the axis of the downpipe connecting portion the throat portion is curved and has a radius of curvature substantially greater than 2 inch (12.5 mm).

More preferably the radius is substantially greater than 2 inch around all of the circumference of the throat portion.

Preferably the radius is in the range 1 to 3 inches and more preferably approximately 2 inches when viewed in a plane longitudinal or axial of the gutter connecting portion.

Ribs of the type disclosed in Patent Specification No. 1,248,204 are provided advantageously in the lower part of the gutter connecting portions and extending down into the downpipe connecting portion to aid the directional flow of water.

The invention will be further described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a cross-section of a know type of running outlet for a rectilinear gutter, marketed by Hunter Plastic Industries Ltd., under the trade mark squareflo, reference R382; Fig. 2 is a side elevation of a rectilinear gutter outlet formed in accordance with the present invention; Fig. 3 is an end view of the outlet of Fig. 2; Fig. 4 is a plan view of the outlet of Fig. 2; Fig. 5 is a perspective view from above and to one corner of the outlet of Fig. 2; Fig. 6 is a cross-section longitudinal of the gutter portion of the outlet of Fig. 2 along the line 6-6 of Fig. 4; Fig. 7 is a cross-section transverse of the gutter portion of the outlet of Fig. 2, along the line 7-7 of Fig. 4.

Figure 1 shows a known type of running outlet 1, incorporating a pipe connecting portion 2, gutter connecting portions 3 and a throat portion 4. The gutter connecting portions 3 are each formed of a short gutter length provided with channel 5 which is adapted to receive a gasket (not shown) for forming a seal with a respective length of gutter (not shown). The radius of curvature of the throat portion 4 in the view shown is 2 inch.

Fig. 2 shows a running outlet incorporating a throat portion 6 having a radius of curvature in accordance with the present invention. Pipe connecting portion 2 is insertable into a downpipe (not shown) which abuts against a lip 7. Gutter portions 3 are provided with channels 5 which receive gaskets as mentioned above.

Fig. 3 shows clipping nibs 8 which retain a gutter length in position against the gutter portion.

Also seen in Fig. 3 are ribs 9 which are provided on the base of gutter portion 3 and extend into the throat portion 6 and aid the directional flow of water in the outlet.

Fig. 4 is a plan view illustrating the square section of the pipe used with this rectilinear type of fitting and gutter. It is to be understood that the invention is applicable to all gutter systems, utilising a variety of gutter cross-section such as the half-round, rectilinear and elliptical. Similarly, circular and other section downpipes may be used.

Fig. 5 is a perspective view from above illustrating the smooth downward curve obtainable at the throat portion with fittings according to this invention.

Figs. 6 and 7 are cross-sections of the gutter fitting of Fig. 2, taken in a plane containing the axis of the pipe connecting portion 2 and taken longitudinally of the gutter portion 3 and transversely thereof respectively. Shown in Fig. 4 are holes 10 for fixing the fitting to the gutter fascia board etc. and stops 11 for preventing creep of gutter across the outlet during expansion and contraction.

It will be understood that the invention is applicable to outlets and gutter systems made from a variety of materials as are known, and that it is particularly readily applied with moulded materials such as plastics.

TABLE 1 Max. Flowrate (litres/min)

Outlet Outlet Outlet Position of Fig. 1 of Fig. 2 Gutter horizontal Central 133 209 Atone end 86 115 Gutter with 1 in 600 Central 160 261 fall At one end 104 136 Table 1 shows results obtained from a test rig utilising a length of rectilinear gutter of width 4.5 inches (1 14 mm) and a single downpipe using a known outlet as shown in Fig. 1, and a modified outlet as shown in Figs. 2 to 7. It will be seen that a considerable increase in the measured capacity of the gutter is found, both with the gutter horizontal and with a 1 in 600 fall.

Claims (11)

1. A method of improving the flow capacity of a gutter system comprising a length of gutter, a downpipe and an outlet, which method comprises adapting the outlet to provide for an increased rate of flow from the gutter into the downpipe.

2. An outlet for a gutter system, comprising a gutter connecting portion, a downpipe connecting portion, and a throat portion between the gutter connecting portion and the downpipe connecting portion, wherein in a plane containing the axis of the downpipe connecting portion the throat portion is curved and has a radius of curvature substantially greater than 2 inch (12.5 mm).

3. An outlet as claimed in claim 2, wherein the said plane contains the axial direction of the gutter connecting portion.

4. An outlet as claimed in claim 2 or 3, wherein the radius is from 1 to 3 inches (25 to 76 mm).

5. An outlet as claimed in claim 4, wherein the radius is approximately 2 inches (51 mm).

6. An outlet as claimed in any one of claims 2 to 5, wherein the radius is within the defined range for substantially all of the perimeter of the throat portion.

7. An outlet as claimed in any one of claims 2 to 6 wherein there are provided ribs extending from the gutter connecting portion into the pipe connecting portion.

8. An outlet for a gutter system, substantially as hereinbefore described with reference to Figs. 2 to 7 of the accompanying drawings.

9. An outlet as claimed in any one of claims 2 to 8, formed of plastics material.

10. The features hereinbefore disclosed or their equivalents in any novel combination.

11. An outlet for a gutter system comprising a length of gutter having a rectilinear cross-section, a downpipe and a said outlet, wherein the outlet comprises a gutter connecting portion of rectilinear cross-section, a downpipe connecting portion, and a throat portion between the gutter connecting portion and the downpipe connecting portion, wherein, in a plane containing the axis of the downpipe connecting portion, the throat portion is curved and has a radius of curvature substantially greater than T inch (12.5 mm).