GULLY ARRANGEMENT

[0001] This invention relates to a gully arrangement which may form, for example, part of a drainage system.

[0002] Conventional drainage systems, for example provided as part of the

infrastructure in residential and commercial areas, receive waste water, sewage and the like from residential premises and convey the waste to a sewage works or the like by way of a sewer which generally runs beneath a road. The drainage system includes a plurality of gullies which are conventionally provided at the side of a road or in another convenient location to receive rain water and transfer the same to the sewer. Such gullies are generally referred to as road gullies.

[0003] Under normal circumstances, such conventional drainage systems

function adequately, but in the event of a flood there is often excess surface water which requires to drain away by way of the road gullies as well as increased flow through the sewer of the drainage system. If the flow through the sewer increases to a rate that the sewer is unable to accommodate, then backflow occurs and waste from the sewer flows back through the gully which may further increase the amount of surface water, but additionally may allow the escape of untreated sewage, which is not only inconvenient but also potentially harmful.

[0004] If a conventional drainage system is unable to cope in flood conditions, then it would be preferable to control the point or points in the drainage system where excess water and/or untreated sewage can escape, ideally at a location remote from residential or commercial areas.

[0005] It is therefore an object of the present invention to provide a gully, such as a road gully, which overcomes, or at least ameliorates, the likelihood of backflow under flood conditions.

[0006] According to the present invention there is provided a gully arrangement comprising: a housing having an inlet at an upper end thereof, a reservoir in a lower region thereof, and an outlet in a side of the housing at a level between the reservoir and the inlet; and a valve provided in an upper region of the housing and adapted to close the inlet in the event liquid in the housing rises substantially to the level of the valve.

[0007] The housing may be provided with a continuous inwardly-extending lip for sealing with the valve. The valve may be adapted to seal with a lower surface of the lip. A peripheral region of the valve may engage with the lip.

[0008] The valve may comprise a flap valve pivotably mounted along one edge thereof.

[0009] The specific gravity of the valve may be less than 1. That is, the valve may be made of a material having a specific gravity less than 1 and/or the valve may be provided with a float, for example along a free edge thereof.

[0010] The valve may be provided with reinforcing ribs, for example extending in two transverse directions.

[001 1] In an open configuration of the inlet, the valve may be received in a recess provided in a wall of the housing.

[0012] The outlet may extend in use in an upwardly inclined direction to form a trap.

[0013] For a better understanding of the present invention and to show more

clearly how it may be carried into effect reference will now be made, by way of example, to the accompanying drawings in which:

[0014] Figure 1 is a cross-sectional view of one embodiment of a gully according to the present invention in a first configuration; and

[0015] Figure 2 is a cross-sectional view of the gully of Figure 1 in a second

configuration.

[0016] The gully shown in Figures 1 and 2 is similar to a conventional road gully, but includes non-return valve means to prevent backflow in the event of flood conditions. Excess water and/or sewage can then be directed to a location set aside to receive the overflow in flood conditions.

[0017] The illustrated gully according to the present invention includes a housing 1 which is conveniently of substantially square or rectangular

configuration. The housing is formed with a reservoir 3 in a lower region thereof and with a conduit system in an upper region thereof. An upper outlet conduit 5 is normally closed by a removable stopper (not shown), while a lower outlet conduit 7 exits the housing at a lower level than the upper conduit 5 and extends in an upwardly inclined direction to communicate with the upper conduit 5 in a lateral protrusion 9 of the housing 1 , the removable stopper and the rising conduit 7 giving rise to a baffle forming a trap between the reservoir and the conduits. The trap prevents the escape of odours from the remainder of the drainage system (not shown). Not all gullies require a trap. The housing 1 may be made, for example, of cast concrete or glass-filled polypropylene or polyethylene.

[0018] Conventionally, one or more courses of bricks 1 1 are provided on an

upper edge of the housing 1 and are surmounted by a grill 13 to prevent large items entering the housing.

[0019] The housing is formed with a continuous inwardly-extending lip 15 around the region of the upper edge thereof so as to form an inlet opening 17, the lower surface of the lip providing a sealing surface. The lip may have a width of, for example, about 25 mm. A flap valve 19 is pivotably mounted along an edge thereof, for example by means of a suitable pivot pin and is movable between first and second positions. The flap valve 19 is configured to close the opening 17 in the first position and is configured substantially not to obstruct the opening in the second position. To this end, in the second position the flap valve 19 is in a substantially vertical position and is received in a lateral recess formed in a side of the housing 1. In the first position, a peripheral region of the flap valve 19 engages with the lower sealing surface of the lip 15 so as to prevent flow out of the opening 17 of the housing. The flap valve 19 may be made of a plastics material, such as acrylonitrile-butadiene-styrene (ABS) or polypropylene.

[0020] The flap valve 19 has an overall specific gravity less than 1 such that it floats on the liquid as it rises within the housing 1. That is, the flap valve may be made of a material, such as a plastics material, having a specific gravity less than 1 and/or the flap valve may be provided with a float 23, for example along a free edge thereof, in order to cause the valve to rise as the liquid level within the housing rises. The flap valve may be provided with reinforcing ribs, for example in two transverse directions in order to reinforce the valve and to reduce flexing thereof.

[0021] In use of the gully shown in Figures 1 and 2, under normal conditions the configuration of the gully is as shown in Figure 1 , that is, the flap valve 19 is pivoted downwardly and is received in the lateral recess formed in the side of the housing and there is free communication between the interior of the gully and the exterior. When water enters the gully, the water level in the reservoir 3 rises and, if it reaches a certain level, will flow out of the gully and into a drainage system (not shown). However, under flood conditions the water level in the reservoir may rise above the outflow conduit 5 due to backflow into the gully from the drainage system. In this case, the flap valve 19 pivots upwardly with the rising water level until the valve contacts the sealing surface provided by the lip 15 around the opening 17 so as to prevent the flow of water out of the gully and into a road or the like.

Thus, in addition to water and/or untreated sewage being unable to escape to the surface through the gully according to the present invention, surface water will not be able enter the gully, and therefore the drainage system, until the flow within the drainage system has diminished

sufficiently for the flap valve 19 to open. Such an arrangement is likely to reduce significantly the time taken for flood water to recede in addition to eliminating the risk of untreated sewage flowing out through the gully.