GB2210803A - Swimming pool filtering arrangement - Google Patents

Abstract

A swimming pool has a peripheral overflow duct 8 from which water is normally returned to the pool through a pump and filter (not shown). The filter is periodically cleaned by reversing the flow therethrough, but instead of using warm water from the pool for this purpose the duct 8 is repeatedly filled with cold water from another source and this water backwashes the filter and is then discharged to waste. The duct 8 shown is defined between two sections of matting 2, but in Fig. 1 a single matting section separates the pool from the duct (5) which is covered by a grating 6. <IMAGE>

Description

SWIMMING POOL FILTERING ARRANGEMENT This invention relates to a swimming pool filtering arrangement.

With known swimming pools, both domestic and municipal, water is pumped from the pool via a filter and back into the pool. To clean the filter, the water flow is periodically reversed so that water is taken from the pool and is passed through the filter in the reverse direction which has the effect of clearing the dirt which has accumulated in the sand or other filtering medium during normal filtration. The dirty water is then dumped through a drain. Such a process normally requires about 10% of the pool water volume and so this water which has been dumped must be replaced and reheated. More disinfecting materials must also be added.

According to one aspect of the present invention, there is provided a method of cleaning a filter of a swimming pool which has a peripheral draining duct, comprising filling at least partly the draining duct with water from an external source and using this water to backwash the filter, the water being drained away after having passed through the filter.

According to another aspect of the present invention, there is provided a swimming pool comprising a draining duct surrounding the periphery of the swimming pool, the draining duct having a conduit leading via a pump and a filter back into the swimming pool and there being means whereby an external source of water can be supplied to said draining duct, the flow of water through said filter being reversible such that, in a backwashing mode, water is fed from said external source, via said draining duct, said conduit and said filter to backwash said filter, the water being led thence to drain away.

The draining duct may be for setting in the ground so that one wall of the duct lies beside the pool, the duct being partially covered by an overhanging draining member which has an upper surface which is sloped towards the duct and which extends over and beyond a second wall of the duct which opposes said one wall, the arrangement being such that, in use, water landing on said draining member flows down into said duct, the draining member acting to absorb the result of any surge of water from the pool.

To accommodate the slope of the draining member, said second wall is lower than said one wall of the duct.

The swimming pool may have a flexible liner of sheet material set into a hollow, the liner extending over a border surface adjacent the hollow, which surface slopes upwardly away from the hollow, the liner extending beyond said surface down into the draining duct, and having in the region of said border surface a matting to provide a non-slip or gripping surface for the user.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a diagrammatic, cut-away perspective view illustrating part of a liner for a deck-level swimming pool installed in a deck level swimming pool, and Figure 2 diagrammatically illustrates an alternative draining arrangement for the deck level pool.

Referring to Figure 1, the liner 1 is of a flexible plastics sheet material such as PVC and has a major central portion 1A set in a hollow forming the major volume of the swimming pool. Beyond the upright walls of the pool, the liner 1 has a border region 1B carrying a strip of matting 2. The border region extends right around the outside of the swimming pool and the strip of matting 2 provides a non-slip or gripping surface for the user in the border region of the pool, since the normal water level, as illustrated at 3, extends onto the border region.

To provide a surface that slopes towards the main volume of the pool, the pool is provided with a glass fibre supporting structure 4 which includes a surrounding draining duct 5. The draining duct 5 is partly covered by spaced-apart bars 6 extending across the duct 5 and resting on ledges 7 thereby forming a draining grille.

The edge of the liner 1 extends beyond the sloping surface provided by the structure 4 and down into the adjacent wall of the duct 5 and is trapped there. This arrangement prevents any water surging over the edge of the sloping surface getting underneath the liner. A concrete beam 11 can be provided beneath the duct 5 to support it.

It will be appreciated that the water level 3 extends onto the sloping surface and onto the matting 2 but any surging of the water easily drains away either over the edge of the sloping surface into the duct or directly back into the pool through the matting, whose tortuous stranded structure is such as to allow almost unimpeded flow of water through it.

Instead of the grille draining arrangement shown in Figure 1, a form of drain duct 8 can be provided as shown in Figure 2.

In this case also, the walls 8A of the drain duct 8 are also made of fibreglass and the arrangement is such that a sloping surface formed by a sloping slab 9 is provided, the slope being towards the duct and pool and preferably of the same or similar angle of slope as the sloping surface provided by the fibreglass structure 4 beneath the matting 2.

The sloping slab 9 partially covers the upper side of the duct 8 and the edge of the slab 9 closest to the pool itself is at a lower level than the highest part of the sloping surface beneath the matting 2, this highest part forming the uppermost boundary of the wall of the duct 8 which is closest to the pool. Preferably, the difference in height between the edge just mentioned of the slab 9 and the highest point of the duct 8 is about 3 cm. The gap between the edge just discussed of the slab 9 and the opposed wall of the duct 8 nearest the pool is about 2 cm. The slab 9 adjacent the edge 9A overhangs the duct 8 by about 5 cm.

The slab 9 can also be at least partially covered by the matting 2 as shown.

It will be appreciated that the form of draining arrangement shown in Figure 2 has advantages over that shown in Figure 1 in that a surge of water running over the sloping surface can largely be accommodated on the sloping surface of the slab 9 which will then run of its own accord into the duct 8 and only a comparatively small gap strip is needed all the way around the duct.

The swimming pool can be of any desired shape, for example, circular or rectangular and the liner 1 can be set in the hollow against screeded earth or the walls of the pool can be formed by a block wall 10.

In both embodiments illustrated, the draining duct is connected by one or more conduits via a pump and a filter (which may be a sand filter or other) back to the pool. The draining duct has a large capacity and in normal use it is intended that about 20% of its volume should be full of water. Water spills into the duct from the pool when it is pushed over the edge by the action of the pump and when people jump into the pool.

The level of water in the duct is controlled by a sensor, and with the duct being only about 20% full of water normally, this allows the remaining 80% or so to act as a ballast tank, thereby obviating the need for a separate ballast tank. To backwash the filter, the draining duct is filled with cold water from an external source such as from the mains and it is this water that is fed through the filter in the reverse direction to normal to flush the debris out of it, the soiled water being led to a drain. The process is repeated a sufficient number of times to backwash the equivalent of about 10% of the water in the pool, this being the normal, hitherto required volume of pool water needed to backwash the filter. Thus, if the draining duct has 1/20th of the volume of the water in the pool, then the backwashing process is performed twice. In practice, the draining duct would have a smaller volume than that, so that maybe the process is repeated ten times. Although the process could be controlled manually, it is preferred that a microprocessor be employed. This enables the water levels to be closely monitored and the backwashing to be performed automatically when required.

Backwashing in fact occurs when a sensor at the filter detects a rise in pressure in the filter as a result of debris build-up. Leaks from the pool are able to be detected also and the system can generally check for any malfunctions. The flow through the pump and filter can be directed as needed by a five-part valve.

Thus, normally, the sensor in the draining duct acts to keep the water level in the duct at about 20% of the volume of the duct. If the level drops for any reason, then the sensor acts to supply fresh water from the mains to replenish the loss. The sensor of course acts to cut off the supply once the loss has been replenished.

A second sensor can be located in the draining duct, this second sensor being located at a higher position than the first one. If for any reason the water level reaches this higher level, then the second sensor acts to cause the surplus to drain away.

By utilising the water in the draining duct to backwash the filter, energy is saved by not having to reheat the water from the pool itself which has to replace the water dumped through the drain. Also, the chemically balanced pool water will not be affected by low or high pH values in the mains water and so no additional chemicals are needed to correct that balance.

Claims (11)

1. CLAIMS : 1. A method of cleaning a filter of a swimming pool which has a peripheral draining duct, comprising filling at least partly the draining duct with water from an external source and using this water to backwash the filter, the water being drained away after having passed through the filter.
2. 2. A method according to claim 1, wherein the method is repeated a sufficient number of times to backwash the filter the equivalent of substantially ten per cent of the normal pool capacity.
3. 3. A method according to claim 1 or 2, wherein backwashing is started when a sensor at the filter detects a rise in pressure in the filter as a result of debris build-up.
4. 4. A method of cleaning a filter of a swimming pool which has a peripheral draining duct, substantially as hereinbefore described with reference to the accompanying drawings.
5. 5. A swimming pool comprising a draining duct surrounding the periphery of the swimming pool, the draining duct having a conduit leading via a pump and a filter back into the swimming pool and there being means whereby an external source of water can be supplied to said draining duct, the flow of water through said filter being reversible such that, in a backwashing mode, water is fed from said external source, via said draining duct, said conduit and said filter to backwash said filter, the water being led thence to drain away.
6. 6. A swimming pool according to claim 5, wherein said draining duct is for setting in the ground so that one wall of the duct lies beside the pool, the duct being partially covered by an overhanging draining member which has an upper surface which is sloped towards the duct and which extends over and beyond a second wall of the duct which opposes said one wall, the arrangement being such that, in use, water landing on said draining member flows down into said duct, the draining member acting to absorb the result of any surge of water from the pool.
7. 7. A swimming pool according to claim 5 or 6 and having a flexible liner of sheet material set into a hollow, the liner extending over a border surface adjacent the hollow, which surface slopes upwardly away from the hollow, the liner extending beyond said surface down into the draining duct and having in the region of said border surface a matting to provide a non-slip or gripping surface for the user.
8. 8. A swimming pool according to claim 5,6 or 7, wherein a sensor is provided to detect a rise in pressure in the filter as a result of debris build-up and thereby to start backwashing of the filer.
9. 9. A swimming pool according to any one of claims 5 to 8, wherein a sensor is provided in the draining duct to keep a certain water level in the draining duct to provide water for backwashing the filter upon starting of the backwashing process, the remainder of the capacity of the duct allowing the duct to act as a ballast tank to accommodate water surge from the pool.
10. 10. A swimming pool according to claim 9, wherein a second sensor is located in the draining duct to sense if water in the duct reaches a certain level, which sensor then acts to cause surplus water to drain away.
11. 11. A swimming pool, substantially as hereinbefore described with reference to the accompanying drawings.