GB2229175A - Water purification apparatus - Google Patents

Abstract

An apparatus 10 is provided for purifying and sterilising water. The apparatus 10 has three chambers 16, 18 and 20 two of which 16 and 20 are filled with silica sand and act as filters, and one of which 18 is filled with activated carbon and removes excess colour taste and odour from the water being treated. The apparatus further comprises a chlorine tablet dispenser 14 and alum pot 28. A valve 34, 36 and 40 and pipe arrangement enables the flow of water to be controlled such that the two filtrating agent chambers 16 and 20 can be operated in tandem or independently of one another thereby enabling clean water produced from one of the chambers 16, 20 to backwash the other. <IMAGE>

Description

DESCRIPTION WATER TREATMENT APPARATUS The present invention relates to an apparatus for purifying and sterilising water.

Large scale water treatment apparatus are known but there is a great need for a small portable apparatus which can be used to provide clean sterile water in a variety of situations. UV radiation has been used to date to sterilise the water in such smaller apparatus but such a method does not lend itself to the production of a suitably small portable apparatus since UV units are bulky.

A small portable apparatus may for example be required to provide a complete water treatment to household water supplies, offices, hotels and the like.

For example, hospitals require ultra-pure sterile water, hotels require pure drinking water for guests and industry may require pure water for adequate functioning of their machines and processes.

A small portable apparatus would be of particular benefit in mobile systems. For example by fitting an apparatus to a vessel travelling in fresh water the vessel's water needs, including drinking water could be met from the water in which they sail.

Drinking water on trains and planes could be provided irrespective of the pick-up source and safe consumption by passengers could be achieved without fear of whether the initial source was contaminated.

Such an apparatus would be of particular use to those working in areas where the water supply is particularly likely to be contaminated. Thus, for the military forces, relief and emergency workers and in developing and third world countries pure water could be simply and cheaply obtained.

The object of the present invention is to provide an apparatus which can operate continuously rather than batchwise, and which purifies as well as cleans water, is small, light and, which can be produced cheaply enough, to enable it to be readily transportable and available in sufficient quantities.

According to the present invention there is provided a continuously-operable water purification apparatus comprising an inlet for untreated water and an outlet for purified water, filtration and sterilisation units located therebetween formed by two outer sand filters and an inner carbon filter respectively, said apparatus having means for introducing chlorine to the untreated water and a valve system enabling the flow of water therethrough to be controlled such that each of said outer sand filters can be operated in tandem or independently of one another thereby enabling clean water produced from one sand filter to be used to backwash and clean the other.

In one embodiment, a source of water, which may be contaminated, is fed by a pump into the apparatus via the water inlet. It passes into an alum pot where it is acted upon by flocculents therein and by chlorine dispensed from an associated tablet dispenser assembly.

Chlorine may be dispensed into the untreated water at a rate which is controlled by the rate of flow and pressure of the water introduced into the apparatus.

Using the valve system the water is then filtered through both sand filters to eliminate debris. The flow of water through these cylinders is preferably horizontal thereby enabling backwashing to be conducted more easily.

Chlorine is introduced into the water in a massive dose to create an overkill situation as far as the impurities are concerned. The water is later forced through the inner carbon filter to remove this excess chlorine and provide a colourless, odourless and tasteless potable water.

A specific embodiment of the present invention will now be described by way of example with reference to the acompanying drawings, in which: Fig. 1 is a perspective view of one embodiment of the apparatus in accordance with the present invention; Fig. 2 is a schematic diagram showing the flow of water and valve positions when the apparatus is in filtration use; Fig. 3 is a schematic diagram showing the flow of water and valve positions when the apparatus is undergoing backwashing of one of the sand filters; and Fig. 4 is a schematic diagram showing the flow of water and valve positions when the apparatus is undergoing backwashing of the other sand filter.

The water purifying apparatus 10 comprises a basic unit 12 and an integral tablet dispenser assembly 14.

The unit may be made of a synthetic plastics material such as UPVC so that it is corrosion-free, the only moving parts are the valves referred to hereafter. The basic unit comprises three filtration chambers 16, 18, 20. These chambers are disposed next to one another in a single horizontal plane, between two vertical supporting plates 22 and 24. The two outer filtration chambers 16 and 20 are filled with silica sand and these chambers function to remove dirt and other foreign particles from the water as it flows therethrough, whilst the inner chamber 18 is filled with activated carbon which functions to remove any excess colour, taste or odour from the filtrated water.

The water is introduced to the apparatus by means of gravity flow or a pump to the apparatus through an inlet 26 and travels under pressure into the alum pot 28 and up into the tablet dispenser 14. The water rises in the tablet dispenser to a point at which the water pressure equals the air pressure acting on the tablet dispenser thereby establishing proportional dosing. Thus the higher the water pressure, the further up the tablet dispenser the water will flow thereby disolving a higher proportion of the chlorine tablets 30 filled therein.

The chlorine dosed water leaves the alum pot 28 and tablet dispenser unit with a chlorine concentration of about 4ppm, it then continues its path along piping 32 to two L-port valves 34 and 36 disposed above chamber 16 and 20 respectively.

When valves 34 and 36 are in a first position (Fig.

2) untreated water flow into outer chambers 16 and 20.

In a second position (Fig. 3), the flow of water can be controlled, so that untreated water only enters chamber 16, and the cleaned water flows the opposite way through chamber 20 in a process known as backwashing. In a third position (Fig. 4), the flow of untreated water can be controlled such that it enters only chamber 20 and the cleaned water eminating therefrom flows the opposite way through chamber 16 in a process known as backwashing. Thus it can be seen that control of valves 34, 36, in association with outlet valves 38 and 40 the flow of water can be controlled allowing both filtration and self-cleaning by backwashing to be carried out.

When filtering untreated water, the water is directed into each of the chambers 16 and 20 at the end nearest front plate 24 by valves 34 and 36 and flows horizontally through the sand filters towards backplate 26, where the filtered water leaves by means of a pipe which takes the water to the inner chamber 18. Prior to entering chamber 18, the pipes leading from chambers 16 and 20 converge into a single pipe which enters chamber 18 near to the back plate 26. In filtration use, valve 40 is kept open thereby allowing clean and sterilised water to flow from the outlet 42 of the apparatus.

Thus, in normal operation the water enters sand chambers 16 and 20 at one end from above and travels in a downwards and lateral direction to the other end thereof where it is picked up and transferred to the upper and far end of the chamber 18 containing activated carbon.

The water then travels through chamber 18 in a generally horizontal direction to a water outlet 42 where it leaves via a valve 40 as pure clear potable water. By passing the water through the carbon filter, the concentration of chlorine can be lowered from 4 parts per million to around 0.15 to 0.20 parts per million.

In use, the apparatus can be operated continuously to purify up to 150 gallons of water an hour. Firstly, the water is passed through the alum chamber where a flocculent, such as aluminium sulphate is introduced and causes precipitation of any foreign particles in the water, whilst at the same time the untreated water is subjected to sterilisation as a result of the water passing through a tablet dispenser containing chlorine tablets. By proper control of the valves 34, 36 and 40, water is allowed to flow through both of the two outer sand filters 16 and 20 before passing through the inner carbon filter 18. One important feature of the apparatus is that a simple operation known as backwashing can be conducted on a regular basis to keep the system clean. This has advantages over other apparatus which require the periodic changing of filters.To conduct backwashing, the flow of water is altered by means of valves 34, 36 and 40 so that firstly, the water is purified by passing it through one of the sand chambers 16 and 20 and then, instead of immediately passing the water through chamber 18, the treated water obtained from chamber 16 or 20 is passed back through the other chamber 16 or 20 and out via an outlet 44.

This operation takes approximately 10 to 15 minutes and when the apparatus is used on a normally dirty water supply such backwashing should only be required once every 3 to 4 weeks. Having cleaned one of the filters 16 and 20 the procedure can be repeated for the other filter 16 or 20 by varying the positions of valves 34, 36 and 40 such that the water flows in the opposite direction.

Whilst the apparatus and method of operation has been described with reference to a particular embodiment, in certain circumstances it may be preferable to use several apparatus arranged in parallel to increase the volume of water which can be treated continuously.

Furthermore, where the water to be purified is of an abnormally high or low acidity, the apparatus described can be used in conjunction with a pH controlling unit. Similarly, where the water contains unacceptably high levels of undesirable metals e.g.

lead, zinc and manganese, a mineral collection unittmay be used in association with the units already described.

Claims (22)

1. A water purification apparatus comprising an inlet for untreated water and an outlet for purified water, two chambers for a filtrating agent and a chamber for a water purifying agent, said apparatus further comprising means for introducing chlorine into the untreated water, and a pipe and valve system enabling the flow of water through the apparatus to be controlled such that each of said two filtrating agent chambers filtrating agent can be operated in tandem or independantly of one another, thereby enabling clean water produced from one of said filtration agent chambers to be used to back wash and clean the other.

2. An apparatus as claimed in claim 1 wherein the components are connected to one another such that in use water will enter via said water inlet, pass through said means for introducing chlorine, through said filtration agent chambers and the purifying agent chamber and exit said apparatus via said outlet.

3. An apparatus as claimed in either of the preceding claims containing a filtration agent in the form of sand.

4. An apparatus as claimed in any one of the preceding claims containing a purifying agent in the form of activated carbon.

5. An apparatus as claimed in any one of the preceding claims in which the valve system comprises two valves via which, the flow of water into one or both of the filtration agent chambers can be controlled, and a valve via which the flow of water from said purifying agent chamber can be controlled.

6. An apparatus as claimed in claim 5 wherein the two valves via which flow of water into one or both of the filtration agent chambers can be controlled are L port valves.

7. An apparatus as claimed in claim 5 or 6 wherein the valve via which the flow of water from said purifying agent chamber can be controlled is an on/off valve.

8. An apparatus as claimed in any one of the preceding claims wherein the chambers are juxtaposed in a single horizontal plane.

9. An apparatus as claimed in claim 8 wherein the two filtration agent chambers are disposed one on either side of said purifying agent chamber.

10. An apparatus as claimed in any one of the preceding claims wherein the means for introducing chlorine to the untreated water is a tablet dispenser.

11. An apparatus as claimed in claim 10 in which an alum pot is associated with said tablet dispenser.

12. An apparatus as claimed in claim 11 wherein the alum pot contains a flocculant.

13. An apparatus as claimed in claim 12 wherein the flocculant is aluminium sulphate.

14. An apparatus as claimed in any one of the preceding claims made substantially from a material which is non corrosive.

15. An apparatus as claimed in claim 14 in which the non corrosive material is a synthetic plastics material.

16. An apparatus as claimed in claim 15 wherein the synthetic plastics material is UPVC.

17. An apparatus as claimed in any one of the preceding claims in which the only moving parts are the valves.

18. An apparatus as claimed in any one of the preceding claims which further comprises a pump.

19. An apparatus as claimed in any one of the preceding claims which further comprises a pH control unit.

20. An apparatus as claimed in any one of the preceding claims which further comprises a mineral collection unit.

21. A water purification apparatus substantially as herein described with reference to and as illustrated in figures 1 to 4.

22. A plurality of apparatus as claimed in any one of the preceding claims when arranged in parallel.