GB2192655A

GB2192655A - Slot drain throat

Info

Publication number: GB2192655A
Application number: GB08716907A
Authority: GB
Inventors: Geoffrey Edward Austin
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-07-18
Filing date: 1987-07-17
Publication date: 1988-01-20
Also published as: GB8617668D0; GB2192655B; GB8716907D0

Abstract

A throat (3) for a slot drain pipe is flared in transverse section such that its upper opening (4), which is adapted to receive in-flow of water (6), is less wide than its lower opening; which is adapted to be joined to a slot drain pipe (1). The throat is provided with fins (7) which extend transversely between the internal throat sides and are inclined to the vertical so as to provide water (8) falling down the throat into the slot drain pipe with a common horizontal flow component. <IMAGE>

Description

SPECIFICATION Slot drain throat This invention relates to slot drains, and more particularly to a throat for a slot drain pipe.

Slot drains are surface water drainage systems by which the water drained off a surface enters the carrier pipe, which is generally horizontal, by means of an upper slot in the pipe parallel to the axis of the pipe. This slot usually has a throat to space the pipe soffit from the surface.

As the flow of surface water into a slot drain is usually tangential to the axis of the drain pipe, there is no component of that flow in the direction of the pipe axis. Water from the surface enters the drain pipe via the throat and the entry of the water tends to disturb and interupt the flow of water in the pipe. As a result, silt tends to build up in such pipes, and has to be cleared out periodically.

An object of the present invention is to overcome the above disadvantage of conventional slot drains by the provision of an improved throat for a slot drain which produces a self-cleansing effect in the slot drain pipe.

The present invention accordingly provides a throat for a slot drain pipe, said throat being fiared in transverse section such that its upper opening, which is adapted to receive inflow of water, is less wide than its lower opening, which is adapted to be joined to a slot drain pipe, and having diaphragms extending transversely between the internal throat sides, characterised in that the diaphragms are inclined to the vertical so as to provide water falling down the throat into the slot drain pipe with a common horizontal flow component.

The flare to the throat has the result of preventing blockage of the throat. This is because any object which is able to enter the smaller opening at the top will be able to pass through the wider lower opening.

The diaphragms in the throat arse preferably substantially parallel to each other so that the horizontal flow component given to the downflowing water is substantially uniform along the drain pipe. The angle of the diaphragms relative to the horizontal can be varied according to local conditions, depending on the expected flow of water. For example, in tropical conditions where heavy rain fali may be expected, the diaphragms may be positioned at a smaller angle relative to the horizontal (e.g.

30 ) than in temperate conditions where a larger angle (e.g. 45 ) may be more suitable.

The diaphragms are preferably straight to min imise manufacturing costs, although curved or otherwise shaped diaphragms might be suitable in certain circumstances.

The pitch of the diaphragms, i.e the spacing between adjacent diaphragms, is preferably such that there is a slight overlap, when viewed in a vertical direction, between one diaphragm and the next. This is so that substantially all the water flowing into the throat is provided with the horizontal flow component. If there were to be gaps between adjacent diaphragms, then some water would be permitted to fall vertically into the drain pipe, and this would tend to disturb the flow conditions.

Reference is now made to the accompanying drawings, in which: Figure 1 is a transverse section of a slot drain in which the drain pipe is provided with a throat according to an embodiment of the invention; and Figure 2 is a longitudinal section of the slot drain on the line A-A of Figure 1.

The slot drain incorporates a substantially horizontal cylindrical drain pipe 1 having a longitudinal slot 2 along its upper surface. A throat 3 is joined to this slot, the throat having sloping sides so that it is flared in transverse section, its upper opening 4 being less wide than its lower opening which is in common with the slot 2.

In use, the drain pipe 1 is positioned below a surface 5 from which water is drained, the water flow along this surface being shown by arrows 6 and being substantially tangential relative to the axis of the drain pipe and entering the throat 3 at its upper opening.

A plurality of diaphragms 7 are provided in the throat and extend transversely between the internal throat sides. These diaphragms are inclined to the vertical so as to provide water falling down the throat, indicated by arrows 8, with a common horizontal flow component, i.e. in the direction of flow 9 of the water in the drain pipe.

The diaphragms 7 are straight and substantially parallel to each other. The pitch of the diaphragms is such that they overiap slightly in the vertical direction, so that substantially all of the water flowing down the throat into the drain pipe is provided with the same horizontal flow component.

In principle, any materials can be used for construction of the slot drain. Plastics materials of appropriate grade are particularly suitable, but it is also possible, for example, to use cast iron, steel or concrete.

In contrast to previous designs of slot drains, where vertical down-flow of water through the throat results in turbulance in the drain pipe and deposition of silt, the horizontal flow component of the water produced in the present invention results in a smooth flow of water in the drain pipe with a consequent self-cleansing effect. Moreover, the rate of flow of water in the drain pipe is also im proved. According to the invention, all fluids collected are deflected by the angled dia phragms thereby inducing and enhancing the drainage flow in the drain pipe.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Slot drain throat This invention relates to slot drains, and more particularly to a throat for a slot drain pipe. Slot drains are surface water drainage systems by which the water drained off a surface enters the carrier pipe, which is generally horizontal, by means of an upper slot in the pipe parallel to the axis of the pipe. This slot usually has a throat to space the pipe soffit from the surface. As the flow of surface water into a slot drain is usually tangential to the axis of the drain pipe, there is no component of that flow in the direction of the pipe axis. Water from the surface enters the drain pipe via the throat and the entry of the water tends to disturb and interupt the flow of water in the pipe. As a result, silt tends to build up in such pipes, and has to be cleared out periodically. An object of the present invention is to overcome the above disadvantage of conventional slot drains by the provision of an improved throat for a slot drain which produces a self-cleansing effect in the slot drain pipe. The present invention accordingly provides a throat for a slot drain pipe, said throat being fiared in transverse section such that its upper opening, which is adapted to receive inflow of water, is less wide than its lower opening, which is adapted to be joined to a slot drain pipe, and having diaphragms extending transversely between the internal throat sides, characterised in that the diaphragms are inclined to the vertical so as to provide water falling down the throat into the slot drain pipe with a common horizontal flow component. The flare to the throat has the result of preventing blockage of the throat. This is because any object which is able to enter the smaller opening at the top will be able to pass through the wider lower opening. The diaphragms in the throat arse preferably substantially parallel to each other so that the horizontal flow component given to the downflowing water is substantially uniform along the drain pipe. The angle of the diaphragms relative to the horizontal can be varied according to local conditions, depending on the expected flow of water. For example, in tropical conditions where heavy rain fali may be expected, the diaphragms may be positioned at a smaller angle relative to the horizontal (e.g. 30 ) than in temperate conditions where a larger angle (e.g. 45 ) may be more suitable. The diaphragms are preferably straight to min imise manufacturing costs, although curved or otherwise shaped diaphragms might be suitable in certain circumstances. The pitch of the diaphragms, i.e the spacing between adjacent diaphragms, is preferably such that there is a slight overlap, when viewed in a vertical direction, between one diaphragm and the next. This is so that substantially all the water flowing into the throat is provided with the horizontal flow component. If there were to be gaps between adjacent diaphragms, then some water would be permitted to fall vertically into the drain pipe, and this would tend to disturb the flow conditions. Reference is now made to the accompanying drawings, in which: Figure 1 is a transverse section of a slot drain in which the drain pipe is provided with a throat according to an embodiment of the invention; and Figure 2 is a longitudinal section of the slot drain on the line A-A of Figure 1. The slot drain incorporates a substantially horizontal cylindrical drain pipe 1 having a longitudinal slot 2 along its upper surface. A throat 3 is joined to this slot, the throat having sloping sides so that it is flared in transverse section, its upper opening 4 being less wide than its lower opening which is in common with the slot 2. In use, the drain pipe 1 is positioned below a surface 5 from which water is drained, the water flow along this surface being shown by arrows 6 and being substantially tangential relative to the axis of the drain pipe and entering the throat 3 at its upper opening. A plurality of diaphragms 7 are provided in the throat and extend transversely between the internal throat sides. These diaphragms are inclined to the vertical so as to provide water falling down the throat, indicated by arrows 8, with a common horizontal flow component, i.e. in the direction of flow 9 of the water in the drain pipe. The diaphragms 7 are straight and substantially parallel to each other. The pitch of the diaphragms is such that they overiap slightly in the vertical direction, so that substantially all of the water flowing down the throat into the drain pipe is provided with the same horizontal flow component. In principle, any materials can be used for construction of the slot drain. Plastics materials of appropriate grade are particularly suitable, but it is also possible, for example, to use cast iron, steel or concrete. In contrast to previous designs of slot drains, where vertical down-flow of water through the throat results in turbulance in the drain pipe and deposition of silt, the horizontal flow component of the water produced in the present invention results in a smooth flow of water in the drain pipe with a consequent self-cleansing effect. Moreover, the rate of flow of water in the drain pipe is also im proved. According to the invention, all fluids collected are deflected by the angled dia phragms thereby inducing and enhancing the drainage flow in the drain pipe. CLAIMS

1. A throat for a slot drain pipe, said throat being flared in transverse section such that its upper opening, which is adapted to receive inflow of water, is less wide than its lower opening, which is adapted to be joined to a slot drain pipe, and having diaphragms extending transversely between the internal throat sides, characterised in that the diaphragms are inclined to the vertical so as to provide water falling down the throat into the slot drain pipe with a common horizontal flow component.

2. A slot drain throat according to claim 1, in which the diaphragms are substantially parallel to each other.

3. A slot drain throat according to claim 1 or 2, in which the pitch of the diaphragms is such that the diaphragms slightly overlap in a vertical direction.

4. A throat for a slot drain pipe, substan tialiy as hereinbefore described with reference to and as shown in the accompanying drawings.