MXPA06010208A - Water purification system - Google Patents

Abstract

The invention concerns a gravity fed water purification system comprising:- a filtration unit adapted to separate particulate and soluble material from the input water, which unit is in fluid communication with - a chemical dispensing unit such that flow rate of water exiting the filtration unit is controlled by - a flow control means before the water encounters a biocide dispensed by the chemical dispensing unit, the water thereafter being retained in - a retention chamber for a predetermined period of time before exiting the water purification system through - a scavenger means adapted to separate the dispensed biocide from the exit water.

Description

WATER PURIFICATION SYSTEM Technical Field The present invention relates to a gravity-fed water purification system, which provides purified drinking water of superior quality. The water purification system provides consistently high rates of potable water flow over a long period while ensuring the removal of harmful contaminants.

Background and prior art A large population in the world lives in countries where there is a severe shortage of hygienic potable water. People have to depend directly on terrestrial water sources such as wells, lagoons and rivers. Frequently, these water sources are contaminated by sewage, industrial effluents and agricultural by-products such as pesticide residues. It is known to have gravity-fed water filters for domestic use, such as decanter filter, in which water enters the filter element through a series of small perforations to the larger upper part of a trapezoidal shaped filter. and flows through the filter to the narrower bottom in the process, traversing through a porous bed of loose absorbents. Such filters have inherent limitations to achieve effective flow rates, because water is required to pass through a deep bed of absorbent particles and frequently clog after a small amount of water has passed. Moreover, such filters do not effectively separate the harmful pathogens present in the water. WO9529878 (Recovery Engineering Inc. 1995), discloses a water purifying device, comprising a disinfectant unit comprising an iodinated resin unit and an activated carbon unit. This unit has its limitations due to the high cost of iodized resin units. Moreover, the residual iodine present in water can be harmful to some people. Hence, there is still a need to develop improved water purification systems that are not costly to use and are consistently more effective in producing healthy drinking water at the desired rate, while ensuring the removal of all harmful contaminants including particulate matter. and soluble material such as noxious odor, residues of pesticides and other organic matter and also harmful microorganisms such as cysts, bacteria and viruses. It is also very important that all biocide chemicals used to kill the pathogenic microorganisms are removed by the system before the purified water is consumed by people. More importantly, the system must provide the desired consistently high flow of purified water over long periods from a gravity head of a few centimeters. There is also a felt need for a water purification system that does not require cleaning, replacement of parts or frequent maintenance. The prior art does not provide all of these desirable characteristics.

OBJECTIVES OF THE INVENTION In this manner, an object of the present invention provides a gravity-fed water purification system that provides clean potable water at a consistently high flow rate of water of about 100 to 200 ml / minute, over long periods. , where the flow rate does not change appreciably with the change in the inlet water head. Another objective of the invention is to provide a gravity-fed water purification system that provides drinking water that is free of contaminants such as particulate matter and dissolved impurities such as odor, pesticide residues and other organic matter and also harmful pathogens such as quiestes, bacteria and viruses. Yet another object of the invention is to provide a gravity-fed water purification system that does not require any external energy as electrical energy to run the unit. Another object of the invention is to provide a gravity-fed water purification system that does not require the use of expensive replacement parts and therefore provides a low maintenance cost.

BRIEF DESCRIPTION OF THE INVENTION In this manner, the present invention provides a gravity-fed water purification system comprising a filter unit adapted to separate particulate and soluble material from the inlet water, which is in fluid communication with a dispensing unit. chemical, so that the flow rate of water leaving the filtration unit is controlled by a flow control means before the water encounters a biocide dispensed by the chemical dispensing unit, the water being subsequently retained in a chamber of retention lasts a predetermined period before leaving the water purification system through a purifying medium adapted to separate the biocide dispensed from the exit water.

DETAILED DESCRIPTION OF THE INVENTION In this manner, the present invention provides a gravity-fed water purification system, comprising - a filter unit adapted to separate particulate and soluble material from the inlet water, which is in fluid communication with - a chemical dispensing unit, so that the flow rate of water leaving the filtration unit is controlled by - a flow control means before the water finds a biocide dispensed by the chemical dispensing unit, the water being subsequently retained in a holding chamber for a predetermined period before leaving the water purification system through - a purifying medium adapted to separate the biocide dispensed from the exit water. It is preferred that the flow control means comprise a flow control reservoir of pre-selected dimensions adapted to discharge the volume of water required, comprising at least one inlet means for the water inlet from the outlet of said filtration unit. towards the reservoir and at least one siphon discharge means operatively connected to said flow control reservoir and adapted to control the flow velocity of the water from said reservoir. The filtration unit preferably comprises a carbon block filter medium. The carbon block filter medium comprises powdered activated carbon (PAC) and a binder, which are well mixed and made in a block by pressure and heat treatment. Preferably, the PAC is selected carbon derived from bituminous coal, coconut shell or wood coal, or petroleum tar. Preferably, the PAC used has a size uniformity coefficient of less than 2, or more preferably less than 1.5, a carbon tetrachloride number exceeding 50%, more preferably exceeding 60%. Suitable carbon block filter media are those described in GB2390987, more preferably that described in our co-pending application 320 / MUM / 2004. The copending application discloses a carbon block filter medium for use in gravity fed filters comprising powdered activated carbon (PAC) having a particle size such that 95% by weight of the particles passes through 50 mesh and does not more than 12% passes through 200 mesh and a binder material having a melt flow rate (MFR) of less than 5. In addition, the preferred carbon block filter media have 55 to 80% by weight of the particles of PAC in the range of 100 to 200 mesh particle size in the 50% lower volume of the carbon block. By means of the above filtration unit, it is possible to maintain a water flow rate, with a water head of 75 mm, under gravity, of 100-300 ml / min, consistently with the long period without compromising the removal requirements of particulate contaminants of chemical contaminants. The filtration unit can be used in conjunction with other known filtration means, such as sediment filter media, preferably, a washable or replaceable sediment filter to remove fine dust and other micro-particulates. The sediment filter may be a non-woven fabric, preferably a microporous fabric with a pore size suitable for retaining particles of 3 μm and above. Most preferably, the water passes first the sediment filter before passing to the carbon block filter medium. The gravity-fed water purification system of the invention comprises a flow control means that regulates the flow rate of water exiting the filtration unit. The flow regulation is preferably achieved by using means that do not require external energy input, for example, electrical power. The flow control means may include flow choke means such as stopcocks, valves, venturis or deflectors. More preferably, the flow control means can be used as described in our co-pending application 927 / MUM / 2002, which comprises a combination of a straight path and at least one elbow adapted to control the water flow rate. The particularly preferred flow control means for the purposes of the invention are those described in WO2004 / 074182. This last means of flow control comprises a flow control reservoir of pre-selected dimensions adapted to discharge the required volume of water comprising at least one inlet means for the entrance of water from the outlet of said filtration unit to the reservoir and at least one siphon discharge means operatively connected to said flow control reservoir and adapted to control the flow velocity of the water from said reservoir. The water flow rate as described in the above copending application can be regulated to a high degree in the manner of selected dimensions of the control reservoir and selective embodiment of the siphon discharge means of a tubular member of pre-selected dimensions including diameter and shape, preferably an inverted tubular "U / V" shaped member to facilitate flow rate control. The use of this preferred aspect of the flow control means ensures excellent regulation of the water flow rate regardless of the flow rate of water exiting the filtration unit.

The water leaving the flow control means finds a biocide dispensed by a chemical dispensing unit. The chemical dispensing unit is preferably a unit that dispenses the biocide without the use of external energy as electrical energy. It is possible for water to flow through the chemical dispensing unit, configured to deliver the desired concentration of the biocide to the water. The biocide in the chemical dispensing unit may be present in liquid form and be dispensed into the water in controlled quantities. Preferably, the biocide is present in solid form and leaches into the water at a controlled rate when the water contacts the surface of the solid. More preferably, the solid is in the form of one or more tablets. When there is more than one tablet, it is preferred that the chemical dispensing unit copulates a tubular body, in which the tablets are placed stacked one on top of the other. The tablet leaches the biocide into the water in a controlled manner and any means can be used to achieve this. Preferably, the chemical dispensing unit of the invention may comprise the chemical sanitization system described in our co-pending application 926 / MUM / 2002. Preferably, during the leaching the tablet dissolves slowly and a new tablet comes in contact with the water as the previous one dissolves. The chemical sanitization system described in the above copending application comprises a sanitization unit containing the chemical sanitizing agents and having an opening at the bottom thereof, means for feeding in water to be sanitized having an upper part as a nozzle selectively disposed adjacent thereunder and that said opening at the bottom of said unit and said upper part as a nozzle having a selective angular conical exterior surface, so as to favor the regulated contact and delivery of said active sanitizing agent on the current contact flowing from the water with the sanitizing agent exposed through said opening. The chemical dispensing unit is preferably of cylindrical cross-section holding the biocide tablets stacked one on top of the other on a perforated disk or a non-woven fabric. There is a water inlet located centrally under the biocide support. Water enters through the entrance, touches the surface of the tablets and exits through the windows (openings) in the periphery of the bra. It is preferred that the biocide be a chemical that delivers active chlorine to water to ensure the death of microorganisms. Any biocide that releases chlorine can be used including chlorinated trisodium phosphate, calcium hypochlorite, lithium hypochlorite, the various N-chlorinated compounds known in the art to release active chlorine, such as sodium or potassium dichloroisocyanurate, trichlorocyanuric acid, monochloramine, dichloramine , [(monotrichloro) -tetra (monopotassium dichloro)] pentaisocyanurate, 1,3-dichloro-5,5-dimethylidethonone, chloramine T, p-toluene sulfodichloroamide, trichloromelamine, N-chloramine, N-chlorosuccinimide, N, N'- dichloroazodicarbonamide, N-chloroacetyl-urea, N, N-dichloroazo-dicarbonamide, N-chloroacetyl-urea, N, N-dichlorobiuryl, chlorinated diacyiamide.

In a preferred aspect of the invention, the water purification system additionally comprises a reporter means which provides an indication when all available biocide tablets are consumed after a period. Preferably, the indicator means provide a visual indication of complete or almost complete consumption of the biocide tablets. Any indicator means known in the art can be used. In particular it is preferred that the indicator means include a colored tablet placed at the top of the biocide tablet stack and a light-transparent window at the bottom of the chemical dispensing unit to allow visual inspection of the tablet below . The colored tablet may be inert, in which case it is highly stable in the biocide and water environment.

When the biocide is a chemical that releases chlorine, the inert tablet is made of a material which is highly inert to the oxidizing properties of chlorine. Alternatively, the inert tablet is coated with a material of preference, a polymeric material which is highly inert to chlorine. In a further preferred aspect of the invention, the water purification system further comprises a water shut-off means which ensures that no more water flows through the flow control means if the biocide is finished. The water closure means preferably comprises said inert tablet. That tablet can be made of magnetic material, preferably iron or nickel, suitably coated with an inert coating for the biocide and a counter magnet can be placed on the bottom of the chemical dispensing unit, so that when the entire biocide is used , the two magnetic pieces are close enough to attract each other, thereby effecting a valve means that ensures the closure of the water leaving the control means. After passing the biocide dispenser, the water containing the biocide is maintained in the system in a holding chamber for a predetermined period. Although it is not desired to link to a theory, it is believed that keeping the water containing the biocide during this period ensures that all pathogenic microorganisms such as bacteria and viruses are killed. It is preferable that the water be maintained for a time that is in the range of 30 to 300 minutes and more preferably 60-180 minutes in the holding chamber. Any means to maintain water during this period in the water purification system can be used. Highly suitable media are illustrated in WO2004 / 000732. An alternate preferred means for ensuring that water is maintained in the holding chamber during this period is by providing riser duct pipes leading the water from the base of the chemical dispensing unit to the holding chamber, which ensures a flow of water. almost laminar water in the retention chamber, which is separated into two or more horizontal sections by baffle plates. The distance between the water inlet to the retention chamber and the water outlet out of each section of the retention chamber is maximized by providing entry and exit points at the distances furthest from each other. This long distance traveled by the water combined with the almost laminar water flow in the retention chamber ensures the desired maintenance time. The water leaving the holding chamber passes through a purifying medium before leaving the water purification system. The purifying medium separates the biocide dispensed from the water. The purifying medium is preferably bacteriostatic activated carbon. Although water can flow through the purifying medium in the downward or upward direction, it is preferred that the water flows through the purifying medium in the upward direction. Various modalities may be contemplated for such a flow, including those described in WO2004 / 014803. According to a further preferred aspect of the invention, there is provided a gravity-fed water purification device comprising: a feeding chamber having a coarse filter through which the water to be purified is fed into the chamber of feeding - a carbon block filter medium and a sediment filter correspondingly configured of nonwoven fabric, which is replaceable / washable adapted to screen particulate and soluble material from the inlet water, - which is in fluid communication with a chemical dispenser unit comprising indicator means, so that the flow velocity of water exiting the filtration unit is controlled by a flow control means comprising a flow control reservoir and a siphon medium before of water finding a biocide dispensed by the chemical dispensing unit, - the water is subsequently retained in a holding chamber for a predetermined period before leaving the water purification system through an upstream flow purifying means adapted to separate the dispensed biocide from the exit water. The invention will now be illustrated with the aid of a specific non-limiting example of a water purification system according to the invention in Figure 1.

Example Figure 1 is an embodiment of the water purification system according to the invention. The system has a feeding chamber (FC) to which the water to be purified is added through a coarse filter (FC), which is adapted to trap large particles. The feed container is of a small height of a maximum of 20 cm, which provides a low gravity head for water filtration through the carbon block filter (CBF) medium. A sediment filter (SF) made of nonwoven fabric and corresponding to the shape of the carbon block filter medium (CBF) is placed therein. The sediment filter removes particulates in the size range of 3 to 6 μm, the carbon block filter separates particles finer than 3 μm, dissolved organics and pesticides. It also filters cysts resistant to chlorine. The carbon block filter water flows by gravity to the flow control means (FCM), which comprises a control tank and a siphon discharge means to effectively control the water flow rate before finding the biocide The safe flow control means that the flow rate is controlled to a very narrow range regardless of the water head in the feed chamber (FC). The biocide is dispensed into the water leaving the flow control medium (FCM) from the chemical dispensing unit (CDU). The chemical dispensing unit has a stack of biocide tablets (BT) and a reporter medium (IM) comprising an inert colored tablet. A transparent window (TM) is provided at the base of the chemical dispensing unit (CDU) through which the indicator means (IM) can be seen once all the biocide tablets are used. The water containing the biocide then enters the retention chamber (RC), where it is held for a predetermined time, in which all viruses and bacteria are annihilated. Baffles (B) are provided in the holding chamber (RC) to ensure a selected path of the water flow and hence the desired retention time. The water then flows in the direction of flow up through the purifying medium (SM), which separates the biocide from the water. The water is then collected in a collection chamber (CC). Purified water free of all contaminants can be dispensed through the tap (T). In this way, it is possible by means of the present invention to provide a simple and cost-effective water-fed water purification system that provides clean drinking water of all contaminants including particulates, microorganisms and soluble matter, including pesticide residues. at the desired high flow rate consistently over a long period.

Claims (21)

1. CLAIMS 1 . A gravity-fed water purification system comprising - a filter unit adapted to separate particulate and soluble material from the inlet water, which is in fluid communication with - a chemical dispensing unit so that the flow rate of the Water leaving the filtration unit is controlled by a flow control means before the water finds a biocide dispensed by the chemical dispensing unit, the water being subsequently retained in a holding chamber for a predetermined period before that it leaves the water purification system through a purifying medium adapted to remove the biocide dispensed from the outlet water. A water purification system as claimed in claim 1, wherein the flow control means comprises: - a flow control reservoir of pre-selected dimensions adapted to discharge the volume of water required, the reservoir comprises at least one inlet means for entering the water from the outlet of said filtration unit to the tank and - at least one siphon discharge means operatively connected to said flow control reservoir and adapted to control the flow velocity of the water from said reservoir. 3. A water purification system as claimed in claim 1 or 2, wherein the filtration unit comprises a carbon block filter medium. 4. A water purification system as claimed in claim 3, wherein the carbon block filter means comprises activated carbon powder (PAC) and a binder material, which are mixed well and a block is formed by pressure and heat treatment. 5. A water purification system as claimed in any preceding claim, wherein a water flow rate of 100-300 ml / minute is maintained under a water head of approximately 75 mm. 6. A water purification system as claimed in any preceding claim, wherein the filtration unit additionally comprises a sediment filter. 7. A water purification system as claimed in claim 6, wherein the sediment filter is a nonwoven fabric with a pore size suitable for retaining particles with a particle size of 3 μm and greater. 8. A water purification system as claimed in any preceding claim, wherein the biocide is present in the form of one or more tablets. 9. A water purification system as claimed in claim 8, wherein the tablets are stacked one on top of the other. 10. A water purification system as claimed in any preceding claim, wherein the biocide is a chemical that delivers active chlorine to water. eleven . A water purification system as claimed in any preceding claim, further comprising a indicating means that provides an indication when all the available biocide is consumed after a period. 12. A water purification system as claimed in claim 1, wherein the indicating means provides a visual indication. 13. A water purification system as claimed in claim 12, wherein the indicator means includes an inert colored tablet placed on top of the biocide tablet stack and a light-transparent window at the bottom of the chemical dispensing unit to allow visual inspection of the tablet below. 14. A water purification system as claimed in any preceding claim, further including a water shut-off means ensuring that no more water flows through the flow control means if the biocide is finished. 15. A water purification system as claimed in claim 14, wherein the water shut-off means comprises said inert tablet made of magnetic material suitably coated with a coating inert to the biocide and a magneto clocado in the bottom of the unit. chemical dispenser, so that when all the biocide is used, the two magnetic pieces are close enough to attract each other, thereby effecting a valve means that ensures the closure of the water leaving the control means. 16. A water purification system as claimed in any preceding claim, wherein the water is maintained for an average time in the range of 30 to 300 minutes in the holding chamber. 17. A water purification system as claimed in claim 16, wherein the water is maintained for a time averaging in the range of 60 to 80 minutes in the retention chamber. 18. A water purification system as claimed in any preceding claim, wherein the retention chamber is separated into two or more horizontal sections by baffle plates. 19. A water purification system as claimed in any preceding claim, wherein the purifying medium comprises bacteriostatic activated carbon. 20. A water purification system as claimed in any preceding claim, wherein the water flows through the purifying medium in the upward direction. twenty-one . A gravity-fed water purification device comprising: - a feed chamber having a coarse filter through which the water to be purified is fed into the feed chamber - a carbon block filter medium and a filter of corresponding shaped non-woven fabric sediment, which is replaceable / washable adapted to separate particulate and soluble material from the inlet water, - which is in fluid communication with a chemical dispenser unit comprising an indicator means, so that The flow rate of water exiting the filtration unit is controlled by a flow control means comprising a flow control reservoir and a siphon means before the water encounters a biocide dispensed by the dispenser unit. chemical, - the water being subsequently retained in a holding chamber for a predetermined period before leaving the system of purification of water through an upstream flow-purifying means adapted to separate the biocide dispensed from the exit water.