US3447329A - Drain structure - Google Patents

Description

J. E. EMBERSON DRAIN STRUCTURE June 3, 1969 Sheet Z 012 Filed Dec. 27. 1965 JOHN E. EMBERSONI mrorneg June 3, 1969 J, E. EMBERSON DRAIN STRUCTURE Sheet Filed Dec. 27. 1965 INVENTOR JOHN E. EMBERSON I Afiorngg United States Patent 3,447,329 DRAIN STRUCTURE John E. Emberson, Scarborough, Ontario, Canada, assignor to Wade International Limited Filed Dec. 27, 1965, Ser. No. 516,470 Claims priority, application Canada, Nov. 20, 1965, 945,828 Int. Cl. E03c 1/26 U.S. CI. 61-63 1 Claim ABSTRACT OF TIHI DISCLOSURE A drain head has a removable plate which contains a notch, the sides of which converge together and are shaped along their length in the form on one half of a parabola bisected through its focus.

This invention relates to a drain structure and has particular reference to a drain structure for controlling the rate of flow of water from a flat roof area into the downpipe and hence to the storm sewer system.

'Drain construction on a flat roof in the past has usually comprised a drain body set into the roof, the lower end of which is connected to the downpipe with the upper end sealed by a flashing clamp over which is positioned a grid sized to prevent the entry of solids large enough to cause blockage. No attempt has been made to control the flow even though there is a limit to the amount of water which the downpipes can handle before overloading occurs with the resultant backing up. A conventional method of dealing with this problem is to provide more downpipes than are generally necessary to deal with the average storm but sufiicient in number to ensure that flooding will not result in the occasional heavy storm; it will be realised though that this method has a disadvantage of increasing the cost of installation of the building.

It is obvious that the downpipes could be more scientifically and economically arranged if a drain structure is employed which would automatically regulate the supply of water to the downpipe irrespective of the nature of the storm.

Accordingly, it is one feature of the invention to provide a drain structure in which the flow rate is directly proportional to the head of water; it is a further feature of the invention that such a drain structure is adapted for incorporation into the flat roof drain construction hitherto employed.

The control of the flow rate through the drain head is accomplished by providing one or more notches in the wall of the drain head, the lower end of each notch being positioned just above roof level. The upwardly extending sides of each notch converge towards each other and are shaped along their length in the form of one half of a parabola bisected through its focus. The flow through such notches referred to hereafter as parabolic is linearly related to the head of Water on the roof; all the notches provide increasing resistance to the drainage of Water and the delay in run off prevents over-loading of the downpipes and storm sewers.

It is a further feature of the drain head according to the invention that the parabolic notches are located in plates which form the sides of a frame, the plates being adapted to be removably secured to the frame, the plates and the frames together forming the drain head. As a result the resistance to drainage of water from the roof may be adjusted by replacing an existing plate with one having a dilferent sized notch.

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The invention will now be described with reference to the accompanying drawings, in which:

FIGURE 1 is a perspective and exploded view of a drain structure according to the invention;

FIGURE 2 is a view of the removable plate of a drain structure according to the invention;

FIGURE 3 is a perspective view of the underside of a drain structure according to the invention.

With reference to the accompanying drawings the drain structure includes a base 10 having a centrally disposed orifice 12 to provide a flange on which are positioned spaced apart integral upstanding lugs 14. A centrally disposed aperture 16 is provided in each of the lugs 14, each aperture 16 serving the purpose of accommodating a respective threaded member 18, each of which extends upwards from an inwardly extending lug 20 of a conventional roof drain body 22 set into the surface of the roof. The threaded members 18 normally serve to secure in place a flashing clamp 24, the threaded members 18 passing through notched abutments 26, the flashing clamp 24 being secured in place by nuts and Washers 28. It is a particular advantage of the invention that the controlled drain structure described hereunder is adapted to be removably secured to the conventional flashing clamp 24 and roof drain body 22. Extending upwards integrally from the flange base 10 is a wall, generally denoted by the numeral 30, forming a frame which, in the preferred embodiment, is substantially square and surrounding the orifice 12. However, it will be appreciated that the configuration of the wall 30 is not necessarily square, e.g. it may be circular.

The frame 30 is provided with opposed apertures 32. A removable plate 34 closes each of the apertures 32; the plate 34 is secured to the frame 30 by means of an abutment 36 which is secured to the underside of the base 10 adjacent the orifice 12 by means of a screw 38, see FIGURE 2. The plate 34 is locked in position by the interaction of opposed flanges 40 hearing against the underside of the frame 30 and a tongue 42 which bears against the outside of the frame 30.

It is a feature of the invention that one or more of the plates 34 is provided with an inverted parabolic notch 44, the size of which is selected with respect to the average storm determined over a reasonable period of time and also relating to the maximum depth of water based on the usual minimum design roof load rating. Generally the size of the parabolic notch 44 is determined on the basis of using a 3" design water level which represents a roof load of approximately 15 lbs. per square foot which is only about half the usual minimum design roof load rating. Since there is a wide variation in rainfall depending on geographic conditions, it will be appreciated that in some cases each plate 34 will have a parabolic notch 44 or else in areas where rainfall is limited only say one plate 34 is provided with a parabolic notch 44, the other plates 34 being blank. The arrangement renders the flow rate directly proportional to the depth of water on the roof with the result that it makes accurate calculations and sizing of the downpipes possible, the maximum width of the parabolic notch 44 being at the bottom which ensures a minimum time for proper draining of the roof after the storm is over. Expressed in another way the arrangement may be such that the flow is below that of the rate previously found with a conventional rating with the result that the sewer system is not overloaded but at the same time the maximum level of water on the roof is kept within a safe limit which is approximately 50% of that for which the roof is designed.

In strict theory the lower edge of the parabolic notch 44 should extend outwards and terminate at the junction of the opposed lower corners of the plate 34 where it joins the wall 30. However, with this construction it is more difiicult to cast -the plate 34 since it will have a sharp corner and also a portion would be provided which could easily break away from the remainder on handling. Accordingly, the lower end of the parabolic notch '44 is turned downwards as at 46 some distance removed from the adjacent lower corner of the plate 34. The area of the parabolic notch 44 thus eliminated by turning down the edge 46 is compensated by deepening the base of the notch 44 in the plate 34 thereby providing comparable flow.

The controlled drain structure according to the invention may be used independently of the conventional roof drain construction but where it is utilized to adapt the latter it is simply secured in place by securing the threaded members 18 in the orifices 12 and applying screws and washers 48. A conventional grid, not shown, would then be positioned over the drain structure to limit the entry of solids which would cause blockage in the downpipe.

While certain embodiments have been illustrated and ated that the invention is not limited thereto, but contemplates such modifications and other embodiments as may be utilized without departing from the invention.

I claim:

1. A drain head secured to a surface area for removing water therefrom, said head including an upstanding wall and a notch in said wall, the lower end of said notch being just above said surface area and the upwardly extending sides of said notch converging towards each other, said sides being shaped along their length in the form of one half of a parabola bisected through its focus; said upstanding wall being removably secured to a frame and said frame being secured to said surface area.

References Cited UNITED STATES PATENTS 810,879 1/1906 Perry 61-10 3,158,171 11/1964 Eckert 137262 3,246,582 4/1966 Wade et al. 9433 REINALDO P. MACHA-DO, Primary Examiner.

J. K. BELL, Assistant Examiner.

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