GB2422330A

GB2422330A - A water supply apparatus

Info

Publication number: GB2422330A
Application number: GB0501021A
Authority: GB
Inventors: Nigel Arthur Paston
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-01-19
Filing date: 2005-01-19
Publication date: 2006-07-26
Also published as: GB0501021D0

Abstract

A water supply apparatus comprises reservoir means 3, water inlet means 4 connectable to a supply of non-potable water 2, water outlet means 9, filtration means 19 adapted to remove a substantial proportion of any suspended solid matter from water intaken from the water supply 2 and means to detect and clear blockage or binding of the filter means with solid matter. Preferably a pressure switch 20 detects any change in pressure caused by blockage or binding of the filter means and preferably allows water in the apparatus to be diverted to copper tubes (28, Fig 2) at the interior of the filter means where the water is directed onto the surface of the filter means causing the filter means surface to be cleared. Advantageously the apparatus is used as a water supply for purposes not requiring mains quality water.

Description

1 2422330

WATER SUPPLY TANK

The present invention relates to a tank for supplying non-potable water to a standpipe, hose or the like. More particularly, but not exclusively, it relates to a break tank for a standpipe or the like that is operable with a feed of water containing particulate matter.

Our UK patent application No. GB2390637 discloses a water supply tank, fed with mains water, usable as a break tank to supply a standpipe for, e. g., washing down possibly contaminated premises, such as sewage works, chemical plants or slaughterhouses, without risking contaminants being sucked hack through the standpipe into a clean mains water supply.

There are many situations, however, in which it is not necessary to use potable mains water for such purposes. Indeed, it would he a waste of resources to use clean, sterile, chlorinated mains water if a suitable alternative were available. Sewage plants, chemical works and the like are usually set up to discharge so-called "final effluent" hack into adjacent watercourses.

There are strict limits on what may he present in final effluent; in general terms, it will normally he slightly cleaner than the watercourse into which it is discharged. This would make it in most regards sufficiently clean to be used for washing down equipment and premises where potable-quality wash water is not required.

The main drawback of final effluent, however, is that it may contain low but significant levels of suspended (inert) solid material. Ihis might cause wear and blockages in pumps, valves and the like, and in any case may simply appear unsuitable for washing and cleaning purposes.

Similar considerations as likely to apply where final effluent water is not available, but it is possible to take water froni a nearby watercourse, a well or the like for washing and cleaning purposes. Again, suspended particulate solids are likely to be a significant problem.

It is hence an object of the present invention to provide a water supply tank capable of supplying wash water at a useful working pressure from a feed containing suspended solid matter. It is a further object of the present invention to provide such a tank that obviates the risk of contamination being drawn back through the tank into the feed.

According to the present invention, there is provided water supply apparatus comprising reservoir means, water outlet means, water intake means connectable to a supply of non- potable water, filtration means adapted to remo'e a substantial proportion of any suspended solid matter from intaken non-potable water, and means to detect and clear blockage or blinding of the filter means by said solid matter.

Preferably, said detection means comprises pressure sensing means so connected to the water intake means as to detect a water pressure drop therein.

Advantageously, said clearing means comprises first pump means operable in response to a pressure drop in the water intake means to deliver water from the reservoir means to the filtration means to clear said blockage or blinding.

Optionally, the first pump means is also so operable in response to a signal from timer means.

The first pump means may also he so operable in response to a manual command.

The first pump means may comprise self-priming pump means.

The first pump means is preferably SO connected to the filtration means that it may produce a back-flush flow of water therethrough.

Advantageously, the filtration means is provided with means to direct said back-flush flow on to a filter medium thereof Said directing means may comprise one or more pipes means extending adjacent said filter medium and having a plurality of orifices directed generally towards the filter medium.

Preferably, the apparatus comprises second pump means to pump water from the supply to the reservoir means.

The second pump means may comprise self-priming pump means.

Advantageously, the apparatus comprises pumping means connected to the water outlet means to augment a delivery pressure of water from the reservoir means.

Said pumping means may comprise the first pump means.

Valve means, such as solenoid valve means, may then be provided, controllable so as to direct water from the first pump means selectably to the water outlet means or to the filtration means.

Preferably, the water supply comprises a final effluent tank, lagoon, stream or the like from a sewage plant, water treatment plant, chemical effluent treatment plant or the like.

Alternatively, the water supply may comprise a watercourse, lake, pond, well, spring, sea or the like.

In a preferred embodiment, the reservoir means comprises at least one wall having a section of lesser height than a remainder of the walls of the reservoir means so as to constitute weir means, such that a water level within the reservoir means cannot rise to a level adjacent a point at which water from the inlet means enters the reservoir means, optionally not within two inches (50 millimetres) of said point.

Advantageously, said section of lesser height extends along a major part of at least one wall of the reservoir means.

An overflow indicator means, such as an overflow indicator pipe, may be provided to warn of likely discharge over the weir means.

The reservoir means is preferably provided with cover means.

The cover means may comprise a top plate and cover side walls extending downwardly from each side of the top plate, dimensioned at least to conceal the weir means.

The cover side walls should be sufficiently spaced from the walls of the reservoir means to allow water to flow down from the weir means between a respective cover side wall and reservoir wall.

The water outlet means is preferably provided with control valve means, such as ballcock means, to interrupt flow of water into the reservoir means when the water level reaches a predetermined level within the reservoir means.

An embodiment of the present invention will now be more particularly described by way of example and with reference to the accompanying drawing, in which: FIgure 1 is a schematic cross-section of a water supply tank embodying the invention; and FIgure 2 is a cross-section of a filter unit isolated from the waler supply tank shown in Figure 1.

Referring now to the figures, and to Figure 1 in particular, a water supply break tank I is supplied with final effluent quality water from a storage tank 2, well, pond, or the like.

The break tank I comprises a reservoir 3, which is filled with water through a water inlet 4, provided with a hallcock valve 5 to cut off an inflow of water to the reservoir 3 when a desired water level 6 therein has been attained. A standard l-3SP ball valve will suffice.

At least one side wall of the reservoir 3 has a weir portion 7 of reduced height, over which water from the reservoir 3 will flow, should the hallcock valve 5 leak or fail, and the water level 6 rise above desired level. As a result, the water level 6 cannot reach the water inlet 4.

and water from the reservoir 3 cannot be sucked back through the water inlet 4 back into the storage tank 2. l'he break tank I is here provided with a cover 8 extending across a top of the reservoir 3 and down beside each of its walls to a level below that of the weir portion 7, thus keeping external material out of the water in the reservoir 3.

The reservoir 3 has an outlet pipe 9 leading from its floor via a first pump 10, a first controlmatic unit II and a regulator 12 to an outlet tap 13, located on an exterior wall of the break tank I. A first draincock 14 is provided in the outlet pipe 9 to allow the reservoir 3 to he drained for cleaning or repair. Note: throughout the Figures, arrows alongside a pipe indicate a direction of water flow therethrough.

The first pump 10 is preferably a conventional self-priming pump, rated at between about 0.25kW and 1.0kW depending on the delivery pressure required, typically 0. 35kW. The first controlniatic unit II is a standard control unit that remains off as long as the water pressure to each side thereof is the same, hut operates the lirst pump 10 should it detect a pressure imbalance. It normally incorporates a non-return valve. The regulator 12 is a conventional compression isolator valve, and ensures that the reservoir 3 is not emptied along the outlet pipe 9 faster than it can be filled. The outlet tap 13 may be a standpipe, a hose connection or the like, as required. A standard 3/4 BSP tap will suffice for most purposes.

Thus, when a user opens the outlet tap 1 3, the first controlmatic unit Ii registers a pressure drop to its downstream side and operates the first pump 10 to deliver water from the reservoir 3 to the outlet tap 13 at a required pressure. Once the outlet tap 13 is closed, the first pump 1 0 runs on for a short period until the pressure on either side of the first controlmatic unit I I has equalised. As water is taken from the reservoir 3, it is replenished through the water inlet 4.

To deliver water to the reservoir 3. an intake pipe 1 5 extends from the storage tank 2, via a second pump 16 to the water inlet 4 of the reservoir 3. A second conirolmatic unit 17 is located downstream of the second pump 16, as is a second draincock 18.

When the hallcock valve 5 opens to replenish the water in the reservoir 3, the second controlmatic unit 1 7 registers a pressure drop downstream and operates the second pump 16 to pump water up from the storage tank 2. As above, once the balicock valve 5 closes the second pump 1 6 is run for a short period until the pressure on either side of the second controlmatic unit 1 7 has equalised.

Because the final effluent water in the storage tank 2 (or equivalent well water or other water source) may contain suspended particulate matter, possibly harmful to pumps, valves and the like, a filter unit 19 is provided, submerged in the storage tank 2 (or equivalent) and connected to the intake pipe 1 5 so that water taken into the break tank 1 is filtered to remove such particulates. (Details of the filter unit 19 are shown in Figure 2, below).

however, as such particulates are filtered out of the water, they will build up on the filter unit, leading to partial or complete blinding or blocking of its filter medium. Passage of water into the intake pipe 15 will he slowed or halted, and the reservoir 3 could run dry.

A first pressure switch 20 is therefi-re tapped into the intake pipe 15 between the storage tank 2 and the second pump 16. This is a standard vacuum switch, adjusted to operate when a preselected pressure drop is detected. The first pressure switch 20 is operatively linked to a first solenoid valve 21, which is located in a backflush line 22, which splits off from the outlet pipe 9 of the reservoir 3, downstream of the first pump 1 0 and the first controlmatic unit 11. The first solenoid valve 21 is a conventional 240V AC solenoid valve, which opens only when powered on. (Note: electrical connections in the figures are represented by dashed lines). The hackflush line 22 leads to an interior of the filter unit 19.

Thus, if the second pump 16 attempts to pump water to replenish a partempty reservoir 3, but the filter unit 19 is partially or completely blocked, a pressure drop will he created upstream of the second pump 1 6. This is registered by the first pressure switch 20, which opens the first solenoid valve 21, taking water from the outlet pipe 9 into the backflush line 22. If the first pump 1 0 is not already in operation at this point, this will cause the first controlmatic unit 11 to turn it on. A high-pressure flow of water will thus be driven by the first pump 10, down the backflush line 22 to the filter unit 19, where it dislodges the collected particulates blocking or blinding the filter medium thereof Once the filter unit 19 is clear, sufficient water will again flow into the intake pipe 15 to re-establish a satisfactory water pressure therein, and the first pressure switch 20 closes the first solenoid valve 21 once more.

Optionally, timed or manual arrangements may also be used to open the first solenoid valve 21 to backflush the filter unit 19 clean, but the above automatic arrangement will usually suffice.

One further èature to allow for the eflécts of the filter unit 19 blocking is a pump priming line 23, leading from the reservoir 3 to upstream of the second pump 16. The second pump 16 is a self-priming pump, SO if no water were entering along the intake pipe 15, it could malfunction. A second pressure switch 24 is therefore fitted in the intake pipe 1 5 downstream of' the second pump 1 6. When this registers a pressure drop, it opens a second solenoid valve 25 in the pump priming line 23, allowing the second pump 16 to take in water from the reservoir 3 until pressure is re-established downstream. The second pressure switch 24 then closes the second solenoid valve 25. The second pump 1 6 is thus always primed and cannot run dry in the short period required fbr the backflush line 22 to clear the filter unit 19.

The filter unit 1 9 is shown in more detail in Figure 2. It comprises a conventional cylindrical filter, with a filter mesh 26 acting as a lilter medium. The intake pipe 15 is connected to an interior of the filter unit 19 via a non-return valve 27.

This conventional arrangement is here supplemented by the pressure of' two or more copper tubes 28 extending within the filter unit 19, close to the filter mesh 26, and connected to the hackflush line 22. (Only one tube 28 is shown so connected, for clarity). Each copper tube 28 is provided with a plurality of orifices 29. When water is driven down the hackflush line 22, it emerges through these orifices as directional jets, directed on to an inner face of the filter mesh 26, to blast away accumulated particulates causing the filter mesh 26 to blind or block.

The break tank I can thus he used as a water supply for washing down premises, equipment and the like, or any other purpose 1101 requiring mains quality water. Even where its water feed contains suspended particulates, the filter unit 19 prevents them entering the reservoir 3.

If there is any blockage of the filter unit 19, leading to an interruption in water supply to the reservoir, tile break tank 1 automatically backflushes the filter unit 1 9 to clear the blockage, and keeps the second pump 16 primed so that water delivery to the reservoir 3 can he resumed as soon as the filter unit is cleaned.

Claims

I. A water supply apparatus comprising reservoir means, water outlet means, water intake means connectable to a supply of non-potable water, filtration means adapted to remove a sLibstantial proportion of any suspended solid matter from intaken non- potable water, and means to detect and clear blockage or blinding of the filter means by said solid matter.
2. An apparatus as claimed in claim 1, wherein the detection means comprises pressure sensing means so connected to the water intake means as to detect a water pressure drop therein.
3. An apparatus as claimed in claim 2, wherein the clearing means comprises first pump means operable in response to a pressure drop in the water intake means to deliver water from the reservoir means to the filtration means to clear said blockage or blinding.
4. An apparatus as claimed in claim 3, wherein the first pump means is also operable in response to a signal from tinier means.
5. An apparatus as claimed in either claim 3 or claim 4. wherein the first pump means is so connected to the filtration means that it may produce a hack-flush flow of water therethrough.
6. An apparatus as claimed in claim 5, wherein the filtration means is provided with means to direct said back-flush flow to a filter medium thereo[
7. An apparatus as claimed in claim 6, wherein the directing means may comprise one or more pipes means extending adjacent said filter medium and having a plurality of orifices directed generally towards the filter medium.
8. An apparatus as claimed in any one of the preceding claims, further comprising second pump means to pump water from the supply to the reservoir means.
9. An apparatus as claimed in any one of the preceding claims, further comprising pumping means connected to the water outlet means to augment a delivery pressure of water from the reservoir means.
10. An apparatus as claimed in any of the preceding claims, further comprising valve means controllable so as to direct water from the first pump means selectably to the water outlet means or to the filtration means.
11. An apparatus as claimed in any of the preceding claims, wherein the reservoir means comprises at lease one wall having a section of lesser height than a remainder of the walls of the reservoir means so as to constitute weir means, such that a water level within the reservoir means cannot rise to a level adjacent a point at which water from the inlet means enters the reservoir means.
12. An apparatus as claimed in claim 11, further comprising an overflow indicator means to warn of likely discharge over the weir means.
13. A water supply apparatus substantially as described herein with reference to the Figures of the accompanying drawing.