WATER RESERVOIR
This invention is concerned with a water reservoir reservoir in particular intended for use in combination with surface water and drain water system.
The systems laid down today taking care of sur¬ face water and drain water are regretfully of economic rea¬ sons dimensioned too small really to cope with the maximum possibly water amounts, which are actually received at reall heavy rains. It would quite simply be too expensive to dimen sion a pipe-line system for these extremely heavy rains, and as they are not a daily occurence an economical/statistical evaluation is made. It should also be mentioned that it is not always a question of dimensionment but sometimes the pi- pes can clog with sludge giving them a reduced transporting capacity. Dislocations in the ground etc. can of course also contribute to this .
A possible way of solving this economical problem would of course be to use a water tank or reservoir temporarily storeing the great amounts of water until the flow of water is diminished. Fortunately most very heavy rains are also rather short. Regretfully the solution of the problem is not quite that simple as to arrange a waterreser- voir. Water reservoirs are also costly and have also other drawbacks. Caissons require large areas and volumes in parti¬ cular since they require a far greater space than the space they provide for taking up water. They are further rather easily clogged. Big tanks reduce the capacity.of the ground for carrying a load and is also very expensive as is also the use of caissons.
Even if it is not economical to prepare onself for these very heavy rains one must also remember that they cause considerable damage when they occure. As a result there is today a great need of a water magazine that can be used eco- nomically- The requirement is a reservoir that can.be used in
combination with new systems as well as with already existing systems.
In order to solve the above problems it is in accor¬ dance with the invention suggested that a water reservoir is fabricated from a roof and a floor connected with each other and supporting the roof on the floor by means of a great number of pipes . The pipes are preferably all perforated so that also their inner volume can be used for the storage of water. Laterally the reservoir according to the invention can be surrounded by fabric- supported by a net, this struc¬ ture only having as it's purpose to prevent soil from ente¬ ring the reservoir. In a preferable method making use of the invention a pipe carrying drain water, surface water or the like is branched of and at a suitable nearby site a suffi- cient amount of earth is excavated to allow the placing of a reservoir according to the invention. The depth of the reser voir is corresponding to the. niveau of the water pipe. The reservoir is- allowed to extend upwards to- a few decimeters below the ground if for instance the site is to be covered bγ grass. Due to the enormous sturdy structure of the reser¬ voir it can however also be placed under a road or street. The reservoir can preferably be surrounded by or the excava¬ tion carried out in an area where the ground consists of clay. The reservoir can be provided with connections extending upwards through a covering layer of soil and grass i.e. in order to allow the flushing and cleaning of the internal of the reservoir. The area covered by the reservoir is calculated corresponding to the required volume of the .'reservoir which is in turn calculated from the amount of "water provided by heavy rains .
Further aspects of the invention will be apparent from the following description of a preferred embodiment shown on the drawings and the appended claims .
In the drawings Fig 1 and 2 shows cross-sections of a reservoir according to the invention, Fig 3 a perspective view
of a part of the reservoir, Fig 4 a detail of the invented device and Fig 5 how a part of the reservoir is transported prior to mounting and" use.
The reservoir embodiment shown in Figs 1-3 consists of vertical perforated pipes 11. These are at their ends closed by means of panels each panel closing a row of in this case five pipes . These panels or lids 1 are for the location of the pipes provided with circular protrusions. Preferably the pipes are press fit over or inside these prot- rusions . The panels are provided with right angled edges with holes therein. These holes serve to fasten the panels to each other s o that united floor and roof surface is obtained. The roof and bottom panels can be identical. In order to clean the reservoir on the inside if sludge is with time deposited there special pipes 6 and 7 are provided extending through the roof down to the bot¬ tom of the reservoir. One 7 of these pipes is used to flush water into the reservoir so that the sludge on the bottom of it is stirred and it can then be removed through a pipe 6 that can also serve as an inlet for water coming from the above lieing surface. Ofcourse yet another pipe 7 or the same pipe can be used for removal of the water with stirred sludge. The pipe 7 is in order to fulfil it's pur¬ pose only opened at the lower end where an oblique cut 8 is made in it. The pipe 6 may also serve to connect the reservo with the atmosphere so that no air pressure is built up in¬ side the reservoir preventing water from entering it. It can also serve as an overflow for the reservoir so that the maga¬ zine is not subjected to pressures that it can not handle. In Fig 3 only a part of a big reservoir is shown.
The panels are interconnected with each other to cover a rather great surface, depending on the requirements tenth or hundreds of square metres. Normally however the depth of the reservoir will be small since it cannot be deeper than the fall of the water. Normal figures will presumably extend
from a couple of decimeters up to a metre or so. The per¬ forated pipes can of course be arranged closer and in a greater number or in a lower number and with greater dis¬ tances between them depending on the loads that is to be taken. One can also within the scoop of the invention have the pipes closer spaced at the edges of the reservoir since it there has to cope with the pressure from the surrounding ground. In some cases one can o -course also consider the use of horizontal pipes as a reinforcement against these forces. The holes a in the side edges of the panels 1 used for bolt connections 2 is around the edges of the reservoir used for the fastening of plastic nets and/or plastic sheets or fabric preventing soil from entering into the reservoir. It is however not necessary that the reservoir is water tight.
In Fig 4 is shown how the panels 1 can be provided with a number of concentric protrusions 3 capable of loca¬ ting pipes 4 with a different width. In Fig 4 the protru¬ sions are all extending on the outside of the pipes but of course it can be the other way around too. This parti¬ cular arrangement with different possible diameters of the pipes results in two great advantages. To start with the pipes can be transported to the location of the reser¬ voir inside each other and this reduction in transported volume reduces the transportation costs.
The second adavantage is that the big diameter pipes can be used along the edges of the reservoir and the smaller diameter pipes on the inside so that the required lateral strength against the pressure from the surrounding soil is obtained. In Fig 5 is shown how pipes and panels can be compactly packed.
The water reservoir according to the invention recei¬ ves a very great water holding capacity in relation to it's volume, the porosity can be calculated to above 97%. This in turn means that the excavated volume can be made rather
small.
Due to the perforations of the pipes and the distan ces between the pipes the water flow through thereservoir is very unrestricted. As has been said above the reservoir is not fabrica¬ ted to be water tight and the bottom of the reservoir does no have to cope with the weight of the water in the reservoir since water will penetrate under the reservoir bottom and takes care of these forces. Of course however the reservoir must be able to cope with the loads imposed on it from above. Normally however these will be very small in compa¬ rison to the load of the water on the inside of the reser¬ voir. It should furthermore be mentioned that the reservoir can due to it's block character be adapted in shape as well as in size to the needs and to the possible site of the reservoir. It is furthermore easy to expand an already built reservoir by simply excavating and_ extending it.
Panels and pipes are preferably made of plastic and in standardized sizes (one or several different) . If it is considered desirable an access manhole can of course be arranged in the roof of the reservoir and a man¬ hole shaft can extend upwards from the reservoir to allow inside inspection and improved cleaning.