Patent Publication Number: US-6905285-B2

Title: Slot drain

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to drainage systems. More particularly, the present invention relates to slot drains or line drains, which facilitate high capacity drainage of surface water or other liquid through a narrow linear slot, while ensuring a high drainage capacity. 
   Slot drains generally consist of cylindrical pipes or channels embedded beneath the surface to be drained with relatively narrow slots or throats extending upwardly from the pipe to the surface. Water present on the surface to be drained enters the throat through the opening in the surface and falls into the pipe or channel via which it is carried away to an appropriate drainage outlet, possibly via a silt box. The main advantage of slot drains is that, although the area of the drainage opening on the surface is small, the conduit along which the water is carried to the drainage outlet is large. This means that the drainage system can cope with heavy rainfall without requiring an excessive area of opening to be present. This is extremely important in some situations such as, for example, on roads and runways where surface water can be hazardous but where large drainage openings would be equally hazardous. 
   GB 2 311 549 discloses a slot drain in which the throat and channel are made from two pieces of steel, which are joined at the region of the base of the channel, each piece of sheet pressed steel forming one side of the channel and one wall of the throat. The hydraulic slot between the throat walls is formed by a series of spacer plates or separators that are welded to the throat walls and can extend the full depth of the throat. Restricted access tends to make the welding operating both tedious and time consuming. The separators are welded to the walls of the throat before the slot drain is galvanised and before being transported to the site at which the slot drain is to be used. 
   It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art. 
   THE INVENTION 
   According to the invention, there is provided a slot drain including a throat portion with two opposed side walls. At least one of the side walls has a hoe therein. The slot drain also includes a separator arranged to separate the side walls by abutment of the walls against opposite sides of the separator. The separator has a lateral projection which passes through the hole and is deformed so it cannot pass back through the hole without further deformation. The respective wall being retained against or adjacent to the separator. A kit of parts is provided for the slot drain. A method of constructing a slot drain includes the steps of passing the lateral projection of the separator through the hole; and retaining the respective wall against or adjacent the separator by deformation of the lateral projection so the lateral projection cannot pass back through the hole without further deformation. A drainage system includes a plurality of slot drains connected end to end. A road or runway includes a drainage system having a plurality of slot drains connected end to end. 
   An advantage of the invention is that the lateral projection of the separator retains the throat side walls from the outside of the throat portion. This allows simple construction and assembly of the slot drain and reduces assembly time. The throat side walls can be fixed to the separators without any specialist tools and without precision workmanship, as the lateral projection on the separator can be mechanically deformed by hand or using a simple mechanical tool. It is not necessary to weld the separator to the inside walls of the throat portion. Thus no sophisticated techniques are required for assembly, and the disassembled slot drains can be assembled anywhere in the world. 
   Preferably, the lateral projection comprises a projecting portion projecting away from the separator in the plane of the separator and a retaining portion parallel to the side of the separator. This provides the lateral projection with a retaining portion which can be deformed either by hand or with the aid of a simple mechanical tool in order to stop the lateral projection from passing back through the hole in the wall. Preferably, the lateral projection is bent about an axis perpendicular to the plane of the wall adjacent the lateral projection. If there is a said retaining portion, the retaining portion is deformed so that it abuts the wall of the throat portion. 
   Alternatively, the deformation may be bent about an axis parallel to the plane of the wall adjacent the lateral projection. In this case, the lateral projection may be bent over towards the wall, either manually or with a simple tool, e.g. a hammer, in order to retain the wall within a predetermined range of separations. 
   As a further alternative, the separator may be arranged to retain the walls by receiving a separate retaining member. This may be achieved by the lateral projection comprising a hole and the retaining member comprising a pin passing through the hole in the lateral projection and abutting the outer surface of the wall adjacent the lateral projection. An advantage of this is that no deformation of the lateral projection is required. The pin may be removable to facilitate disassembly of the throat portion, or may be welded in place. 
   Preferably, the separator comprises a plurality of projections. This provides increased securing of the separator to the walls of the throat portion. 
   Each wall may comprise a plurality of holes. This allow a lateral projection to pass through each hole, or allows adjustability of the separators to allow adjustability of the separation of the throat portion. However, preferably, the respective throat wall has a single hole for each separator. 
   Preferably, an upper projection and a lower projection are provided on a side of the separator, the upper projection providing an upper shoulder against which the upper edge of the respective hole abuts and the lower projection providing a lower shoulder against which the lower edge of the respective hole abuts, in order to locate the separator vertically with respect to the respective throat wall, whether there is one hole or two separate holes. 
   Preferably,.the separator is a flat piece. This allows drainage water to flow freely down the throat portion. Preferably, the lateral projection is integral with the separator. This provides extra strength to the separator. 
   Preferably, each wall has at least one hole. This allows a lateral projection to pass through each wall in order to retain the walls within a predetermined range of separations. 
   Normally, a plurality of separators would be used, spaced along the throat. This provides extra rigidity to the throat portion. 
   Preferably the slot drain also includes a hole adjacent an end of the drain and the lateral projection can be bent so as to project beyond the end of the drain and be adjacent to or touching the throat wall to provide horizontal registration with the end portion of a second drain slot. 
   Preferably, at least one of the separators comprises means for handling the slot drain. When the separator is in position, the slot drain can be handled using the means for handling, so easing positioning of the slot drain. To provide the handling means, the separator can have a lateral handling projection on each side, projecting out through respective holes in the throat walls, and handling holes can be provided in the handling projections. For handling, bars can be inserted in the handling holes so that the bars extend parallel to the slot drain. The bars can be used to lower the slot drain into a trench. Preferably the handling projections are separate from the lateral retaining projections though it may be convenient to arrange for the handling projection to pass through the same hole in the throat wall as a retaining projection. 
   Preferably, at least one of the separators comprises means for securing the slot drain in position when installed. To provide the securing means, the separator can have a lateral securing projection and e.g. a hook can be provided by or on the securing projection, for attaching to an external securing member such as a reinforcement rod or reinforcement mesh. The external securing member may be set in concrete, so providing the slot drain with stability against sideways movement. The handling projection can also form the securing projection. 
   Preferably, the drain is formed from two parts and further comprises a channel portion arranged to carry drainage water through the drain, the two parts being joined at the base of the channel portion. This means that the two parts may be substantially symmetrical, and substantially identical. As the parts can be made of sheet material, the parts can be nested. Thus in addition to the parts being of lighter weight, being formed of sheet material, and thus easier to handle, they can be stacked in nested form for transport, warehousing and on site, taking up less space and reducing the dangers of unstable stacking. In particular, this can greatly reduce transport and warehousing costs. 
   Preferably, a mounting member is provided for mounting the slot drain, the mounting member being connected to the channel. Preferably the mounting member is connected to opposite sides of the channel, and preferably comprises two substantially parallel vertical portions for securing to the channel, the mounting portions being connected by a transverse portion. The transverse portion provides a foot upon which the slot drain may be stood during assembly and fixing in position. The transverse portion may be set in concrete before the rest of the slot drain is covered. 
   Preferably, the transverse portion has a plate connected to it to aid retention in the concrete. Preferably, the plate is at least twice the width of the transverse portion. 
   A collar may be fixed to the mounting member, for joining a second slot drain to the first-mentioned slot drain. If the collar is generally of a U-shape, it provides a simple cradle type joining of two slot drains, the second slot drain resting on the collar so that the sides of the channel are aligned. If the channel portion has a downwardly projecting flange, the U-shape can have a gap at the bottom to accommodate the flange. Preferably, the collar is arranged to be connected to the mounting member in the plane of the sides of the channel of the slot drains. This aids alignment of the two slot drains. 
   Alternatively or in addition, the mounting member may comprise a projecting portion arranged to engage with a second mounting member on a second slot drain. In this alternative, the mounting members provide the alignment between two slot drains. The projecting portion may be arranged to rest on the top of the second mounting member, to provide vertical alignment. The slot drain may have a mounting member with a projecting portion at each end, for cooperating with slot drains having mounting members with no projecting portions. Alternatively, the slot drain may have a mounting member with a projecting portion at one end and a mounting member with no projecting portion at the other end. 
   The slot drain may be formed into a line drainage system comprising a plurality of slot drains. The slot drain can be used in a multitude of applications where surface water drainage is required including roads, airport taxiways and aprons, car parks, warehouses, in fact any hard standing area. 
   As indicated above, the slot drain can be made of two sheet-like parts, suitably profiled. Preferably, the slot drain and/or the separator(s) are made from galvanised or coated steel sheet. 

   
     EMBODIMENTS OF THE INVENTION 
     Embodiments of the invention will now be described, purely by way of example, with reference to the accompanying drawings, in which: 
       FIG. 1  shows a perspective view of a first slot drain according to the present invention, before bending the retaining projections into position; 
       FIG. 2  shows a side view of the slot drain of  FIG. 1 ; 
       FIG. 3  shows an end view of the slot drain of  FIG. 1 , installed in position; 
       FIG. 4  shows a separator in the slot drain of  FIG. 1 ; 
       FIG. 5  shows an alternative separator according to the present invention; 
       FIG. 6  shows a side view of an end of the slot drain of  FIG. 1 , showing the end of another such slot drain, the retaining projection being shown bent into position; 
       FIG. 7  shows a perspective view of a second slot drain according to the present invention; 
       FIG. 8  shows a further perspective view of the slot drain of  FIG. 7 ; 
       FIG. 9  shows a separator in the slot drain of  FIG. 7 ; 
       FIG. 10  shows an end view of the slot drain of  FIG. 7 , installed in position; 
       FIG. 11  shows a perspective view of a mounting bracket of the slot drain of  FIG. 7 ; 
       FIG. 12  shows a further perspective view of another mounting bracket of the slot drain of  FIG. 7 ; 
       FIG. 13  shows a detail of a slot drain according to the present invention incorporating the separator of  FIG. 5 ; and 
       FIG. 14  shows a perspective view of a third slot drain according to the present invention. 
   

   FIGS.  1  TO  6  AND  13 —A FIRST SLOT DRAIN AND A MODIFICATION 
     FIGS. 1 ,  2  and  3  show a slot drain  100  comprising a channel portion  102  and throat portion  104 . The channel portion  102  is substantially hexagonal in shape with the throat portion  104  extending substantially vertically up from the channel portion  102 . 
   The channel portion  102  has six planar sides  106  of substantially equal length. Sides  106  meets at corners  108 . One of the corners  108  is arranged to be located at the lowermost point of the slot drain  100 , substantially diametrically opposite throat portion  104 . The channel portion  102  may be about 300 mm wide. 
   Throat portion  104  consists of two upwardly extending side walls  110 . The walls  110  converge slightly away from the channel portion  102 , so as to form a slightly flared throat, preventing debris from becoming permanently lodged and blocking the opening. The throat opening width may be varied to facilitate variance in the intake capacity of the slot drain. The angle of convergence may be about 4.5°. The slot may be about 30 mm wide. 
   Inside the throat portion  104  are vertically extending spacer plates or separators  112  (see FIG.  3 ). The separators  112  are transverse to the walls  110 , and extend substantially the whole height of the throat between the top and the junction with the channel portion  102 . Alternatively, the separators  112  may be shorter in length, for example extending only half of the height of the throat portion  104 . The separators  112  provide strength and stability to the throat portion  104  to ensure separation of the walls  110  so that the walls  110  do not bow or collapse towards each other. 
   At one end of the slot drain there is provided a first mounting bracket  114 . The mounting bracket is attached to the channel portion  102  on each of its two vertically extending sides  106 . At the other end of the slot drain a second mounting bracket  116  is attached to the vertical sides  106  of the channel portion  102 . 
   The slot drain  100  is formed from two identical parts or halves of e.g. 3 mm galvanised sheet steel. Each half is pressed into shape and comprises one of the walls  110  of the throat portion, together with three of the sides  106  of the channel portion  102 . A flange  118  is provided along the lower side of the half. Prior to assembly, the halves can be nested, with other such halves. In order to assemble, the two halves forming the channel  102  and throat  104  are brought together with the separators  112  between the walls  110 . The two pressed halves are fixed together where the flanges  118  meet. The flanges  118  will be parallel when placed together and are mechanically fixed together using e.g. rivets  119  through the flanges  118 , to provide a join at the bottom corner  108  of the channel  102 . A sealing material or mastic can be introduced between abutting flanges  118  effect a leak tight joint. The sealing material may be a suitable mastic, a suitable tape, for example “DENSO” (RTM), or a suitable rubber seal. The side walls  110  are fixed to the separators  112  as described below. 
   Instead of galvanised steel, the halves could be made from any material suitable for this application, e.g. plastic/GRP/polymer concrete. 
     FIG. 4  shows a separator  112 . The separator comprises a body  120 , the sides of which converge towards the top at the same angle as the wall  110  of the throat portion  104 . The body  120  is flat and has upper and lower lateral retaining projections  122 ,  124  on each side. 
   The walls  110  have holes or slits  128  cut in them. The holes  128  are generally rectangular in shape, the dimensions corresponding to the thickness of the lateral projections  122 ,  124  and the distance between the top of the upper lateral projection  122  and the bottom of the lower lateral projection  124 . The holes  128  in the walls  110  are e.g. laser cut to provide accurate location for the lateral projections  122 ,  124  to pass through the walls  110 . 
   The lateral projections  122 ,  124  pass through the holes  128  in the walls  110 . Each lateral projection  122 ,  124  is L-shaped, being formed of a projecting portion  130  projecting perpendicularly away from the body  120  in the plane of the body, and a retaining arm  132  parallel to the side of the body  120 . The arm  132  of the upper lateral projection  122  extends downwardly, while the arm  132  of the lower lateral projection  124  extends upwardly. This is so that the projecting portions  130  locate on the upper and lower edges of the slit or hole  128 , providing positive vertical location of the separator  112  with respect to the wall  110 . The gap between the side of the body  120  and the inside of the retaining arm  132  is sufficient for the arm  132  to pass through the hole  128  and be bent so that the inside of the arm  132  abuts the external surface of the wall  110 , while the side of the body  120  abuts the internal surface of the wall  110 . The gap need not be exactly the same as the width of the wall  110 . Some play may be introduced. The separators  112 , and therefore the walls  110 , are fixed in place because the retaining arms  132 , once deflected, cannot pass back through the holes  128  without further deflection. 
   Because the slot drain is not welded, it can be assembled on site. A conventional, welded slot drain cannot be assembled on site because the galvanising step must occur after the welding step. If the welding is carried out on galvanised steel then poisonous fumes are produced. 
     FIGS. 5 and 13  show an alternative form for the separator  112 . The separator body  120 A comprises a slot  136 . The slot  136  accommodates a steel plate  138 . The steel plate  138  extends substantially the whole height of the slot  136  and is perpendicular to the plane of the body  120 A. 
   As shown in  FIG. 13 , the steel plate  138  divides the throat in two longitudinally, providing a central support for objects resting on the top of the throat portion  104 , above the slot drain. The steel plate  138  also reduces the size of the minimum dimension of an object which can pass into the throat portion  104 , such as the heel of a shoe. The steel plate  138  is held in place in the slot  136  by compressive force from the sides of the slot  136  caused by force of the walls  110  on the separator  112 . 
   The slot  136  is laser cut for precision. In one embodiment, the slot  136  is 25 mm high and 3 mm wide. 
     FIG. 6  shows the retaining arms  132  of the separator  112  once they have been passed through the holes  128  in the walls  110  and have been bent. All the retaining arms  132  are bent about an axis substantially perpendicular to the plane of the walls  110  (and with a suitable tool, both retaining arms  132  on one side of the separator  112  can be bent simultaneously). This ensures that the walls  110  cannot separate without bending back of the upper and lower lateral projections  122 ,  124 . The retaining arm.  132  of the upper lateral projection  122  is bent to a greater extent than the other retaining arms  132  to provide a lateral location for the next channel. This occurs because the portions of the lateral projections  122  extending beyond the end of the throat portion  104  ensure that a throat portion of a second slot drain is held in register with the throat portion  104  of the first slot drain. 
   The separators  112  can be laser cut or punched from say 3 mm galvanised steel or any other suitable material. 
     FIGS. 3 and 6  show a first mounting bracket  114 . The bracket  114  comprises two vertical members  150  connected at their lower ends by a transverse member  152 . The separation of the vertical members  150  is equal to the distance between the vertical sides  106  of the channel portion  102 , so that the vertical members  150  can be e.g. riveted to the vertical side  106  of the channel portion  102 . The transverse member  152  abuts the flanges  118  at the base of the channel  102 , providing extra structural support for the channel  102 . The vertical members  150  of the first mounting bracket  114  have horizontal arms  162  projecting substantially parallel to the sides  106  of the channel  102 . The arms  162  project from the top of the vertical members  150 . The arms  162  project past the end of the channel  102 . 
     FIGS. 3 and 6  show a second mounting bracket  116 . The second mounting bracket  116  is the same as the first mounting bracket  114  except that there are no horizontal arms  162  extending from the vertical members  150 . Instead, the vertical members  150  extend upwardly only as far as height corresponding to the lower edge of the arm  162  of the first mounting bracket  114 . This gives the effect that when the mounting brackets  114 ,  116  are attached to the channel  102 , two channels can be joined accurately with a first mounting bracket  114  engaging a second mounting bracket  116 . The arm  162  of the first mounting bracket  114  extends to and rests upon the top of the second mounting bracket  116 , when two slot drains are brought together. This means that the ends of all the channel sides on one slot drain register with the corresponding ends of the other slot drains, so that they can easily and effectively be joined. 
   As shown in  FIG. 3 , the slot drains  100  can be lowered into a trench which is then back-filled with concrete  170  to the height of the top of the slot drains  100 . Some arrangement must be employed to prevent the drains  100  rising due to their buoyancy. 
   FIGS.  7  to  12 —A Second Slot Drain 
   The second slot drain  200  is the same as the first slot drain  100 , except that the separators and mounting brackets are altered and the throat portion  204  is less high. 
   As shown in  FIG. 9 , the body  220  of the separator in the second slot drain  200  has a cross-member or lateral handling projection  226  which projects out on each side of the body  220  approximately one third of the way down the height of the body  220 . The cross-member  226  has a securing member or hook  228  on either side of the cross-member  226 , distal to the body. Between the hook  228  and the body, on each side of the cross-member  226 , there is provided a mounting or handling hole  230 , which can be used to lift and move the slot drain  200  into position. The upper and lower lateral retaining projections  222  and  224  are the same as in the first slot drain  100  and function in the same manner. The hooks  228  are attached to e.g. reinforcement mesh  234  (see FIG.  10 ), the mesh  234  being set in concrete to secure the slot drain  200  in position. 
   The separator of the second slot drain  200  may have a vertical slot (not shown) in the body  220 , in the same manner as that shown in  FIG. 5  with regard to the first slot drain  100 . The purpose and arrangement of the slot are the same as for the first slot drain  100 . 
     FIG. 11  shows a detailed view of the first mounting bracket  214  of the second slot drain  200 . As in the first embodiment, the bracket  214  comprises two vertical members  250  connected at their lower ends by a transverse member  252 . The separation of the vertical members  250  is equal to the distance between the vertical sides  206  of the channel portion  202 , so that the vertical members  250  can be connected to the vertical sides  206  of the channel portion  202 . 
   The arrangement is such that a blinding layer of concrete  272  ( FIG. 10 ) is filled into the bottom of the trench, before or after placing the slot drains  200  in position. When it has at least partially set, the remaining concrete  274  is poured and the blinding layer  272  prevents the slot drain  200  rising due to natural buoyancy. Attached to the transverse member  252  is a plate  254 . The plate  254  increases the engagement with the blinding layer  272  while pouring the remaining concrete. The dimensions of this plate  254  should be calculated with respect to the size of the channel portion  202  being used and should minimise the stress in the blinding layer  272  to an acceptable figure with respect to the quality of concrete being used. In one embodiment for example, a channel with body width of 300 mm and a throat height of 300 mm should be provided with a plate of dimensions 455 mm×100 mm. The plate  254  may be attached to the transverse member  252  by rivets. Preferably, the vertical members  250  and transverse member  252  are made from one piece of steel. The plate is also preferably made from steel. 
   A collar  256  is connected to each of the vertical members e.g. by welding. Each of the collars  256  comprises a vertical portion  258  and an inwardly inclined portion  260 , forming a generally U-shaped cradle. The inwardly inclined portion  260  is arranged so that it is parallel with one of the lower sides of the channel portion  202 . A gap is left between the ends of the inwardly deflected portions  260  of the collars  256 , through which the flanges  218  pass when the channel portion  202  is placed in the bracket. The slot drain  200  rests on the collars  256 . The transverse member  252  is therefore separated from the bottom of the channel portion  202 . 
   The vertical members  250  also comprise handling holes  262 . These holes  262  allow attachment of the slot drain units  200  to a jig (not shown) on the surface of the trench via rods (not shown), which facilitates faster and easier installation. 
   This jig is attached at the collar  256  end of the slot drain  200  and has a lateral limiter. By varying the position of the lateral limiter and the length of rod between the holes  262  and the jig, the position of the slot drain  200  in the trench can be set before the blinding layer of concrete  272  is poured. The collar  256  provides positive location for an end of the next slot drain  200 . 
     FIG. 12  shows the second mounting bracket  216 . The second mounting bracket  216  is the same as the first mounting bracket  214 , with the exception that the second mounting bracket  216  has no collars  256 . The second mounting bracket  216  is connected to the channel portion  202  sufficiently far from the end of the channel portion  202  that a collar  256  from a first mounting bracket  214  attached to another slot drain  200  can engage with the sides  206  of the channel portion  202 . 
   The transverse members  252  may be set in a concrete blinding layer  272  which is 7.5 cm deep and has a minimum grade of C 20 -C 25 . The trench is then filled with concrete  274  with the minimum quality grade of C 40 . A layer of pavement quality concrete is placed on the top of the trench. The cross member  226  is arranged such that its top is 7 cm below the surface, the opening of the throat portion  204  being level with the surface. 
   The lateral projections  122 ,  124  or  222 ,  224  need not be deformed about an axis perpendicular to the walls. They may instead be deformed about an axis substantially parallel to the walls, or about a combination of these axes. In fact, any deformation may be used, which need not include rotation at all, as long as the lateral projections cannot pass back through the holes in the walls without further deformation. For example, the lateral projections may be in the form of barbs or hooks. 
   The slot drain  100  or  200  can therefore be assembled without the need for any welding. In addition, the manner of assembly is very simple and is also fast when compared with the previous assembly methods. The assembly of the separators  112  or  212  may be completed without any specialist tools and without precision workmanship. The mechanical assembly of the throat and channel portions by riveting at the base of the channel, and the placement of the separators in the throat by deformation, facilitates on site manufacture, and can result in an eight fold increase in output when compared with the previous method. Transportation costs can be reduced by on site construction, as the parts can be stacked more densely or nested prior to assembly. 
   It should be appreciated that the channel portion may be another shape, other than hexagonal. These may include many types of polygon, regular or non-regular. Some or all of the sides can be arcuate, or the channel portion can be circular or ovoid. If there are no vertical sides to the channel portion, the sides of the mounting brackets can be angled to match any of those of the channel sides. 
   The separators  212  of the second slot drain  200  can be used without alteration in the first slot drain  100 , and vice versa. Similarly, the mounting brackets  214  of the second slot drain  200  can be used in the first slot drain  100 , and vice versa. 
   FIG.  14 —A Third Slot Drain 
   The slot drain  300  of  FIG. 14  is in many respects the same as the slot drain of  FIGS. 7  to  10 , and the same references, with the addition of  100 , are used as in  FIGS. 7  to  10 . 
   As the top of the throat portion  304 , the side walls  310  are provided with horizontally-extending outwardly-turned lips  311 . 
   In the channel portion  302 , the side walls are provided with openings  332 . These serve the purpose of enabling the slot drain to be suspended from the surface of a trench by placing transverse rods through the opening  332  and putting hooks on the transverse rods. As the channel side walls  310  are further apart than the holes  330  in the cross-members  326 , this gives better stability than suspending the slot drain using the cross-members  326 . 
   At the base of the channel  302 , each vertical flange  318  has a horizontal flange  334  along its bottom so that the two horizontal flanges  334  project in opposite directions. The flanges  334  are for resting on a surface and supporting the slot drain  300 , should this manner of installation be desired. The vertical flanges  318  are provided with openings  336  so that concrete can flow through from side to side and securely anchor the slot drain  300  in position in the bottom of a trench. 
   The openings  332 ,  336  can be formed in any suitable way, for instance by laser cutting. 
   For aligning the slot drains  300 , a generally U-shaped cradle can be formed, in effect like the cradle shown in  FIG. 11 , made of the collars  256 , by riveting pieces to one end of the lower half of the channel portion  302 . This riveting can be done before the slot drain is assembled. 
   When using the slot drain of  FIG. 14 , after suspending from the surface as indicated above, the trench can be filled with concrete up to a level slightly below the openings  332 , the concrete allowed to set, the horizontal bars removed, the openings  332  closed with builder&#39;s tape, and the rest of the concrete poured. 
   With suitable modification, the lips  311  and/or the openings  332  and/or the horizontal flanges  334  and/or the openings  336  can be applied to the first and second slot drains  100 ,  200  described above. 
   Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field. 
   Unless the context clearly requires otherwise, throughout the description and the claims, the words ‘comprise’, ‘comprising’, and the like, are to be construed in a inclusive as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”. 
   The present invention has been described above purely by way of example, and modifications can be made within the spirit of the invention. The invention also consists in any individual features described or implicit herein or shown or implicit in the drawings or any combination of any such features or any generalisation of any such features or combination. In particular, the dimensions and ratios given in the description above are not intended to be limiting, but merely examples of possible construction dimensions. Other dimensions giving a slot drain as claimed may also be used. 
   The slot drain is described as though it were in its installed orientation, for convenience. However, during for instance manufacture, transport and storage, the orientation of the slot drain can be otherwise, and the invention extends to the slot drain in such other orientations.