|Title of Invention||
A DISINFECTANT UNIT
|Abstract||The present invention relates to a disinfectant unit for water stored in a container. It is an object of the invention to maintain water held in a container sanitized during storage. The present invention provides a disinfectant unit for maintaining water held in a container sanitised by releasing gaseous disinfectant into the head space of the container while ensuring the disinfectant is spatially seperated from the water to be sanitised.|
|Full Text||FORM - 2
THE PATENTS ACT, 1970
(39 of 1970)
The Patents Rules, 2006
(See Section 10 and Rule 13)
A DISINFECTANT UNIT
HINDUSTAN LEVER LIMITED, a company incorporated under the Indian Companies Act, 1913 and having its registered office at Hindustan Lever House, 165/166, Backbay Reclamation, Mumbai -400 020, Maharashtra, India
The following specification describes the invention
FIELD OF THE INVENTION
The present invention relates to a disinfectant unit for water stored in a container. It is particularly useful for maintaining purified water sanitized during storage.
BACKGROUND AND PRIOR ART
A large population of people in the world live in countries where there is a severe shortage of hygienic potable water. Various types of water purification systems like those that
10 utilize UV radiation, halogenated resins, reverse osmosis, etc are used to purify water. Many resort to boiling of water. A large number of chemical methods of purifying water have been known and used at municipal, local and domestic levels. Some of the disinfection agents such as iodine,
15 bromine, chlorine or ozone are used to reduce the concentration of microorganisms like bacteria and viruses.
Many of the commercially available water purification devices aim at providing water that meet the standards set
20 by EPA. EPA Specifies that water from any unknown origin can be rendered microbiologically safe to drink if removal of log 6 of bacteria, log 4 of virus and log 3 of cysts is attained. Thus a generally accepted removal criteria for bacteria, virus and cysts are log 6, log 4 and log 3 removal
After purification of water, the water is stored for various periods of time before consumption. Heterotrophic bacteria (HPC Bacteria) are widely prevalent in air, soil, foods, and
30 in all sources of water and are generally present throughout the environment. HPC bacteria developed in water that
had been treated by an in-line device such as a carbon filter or softener, in water-dispensing devices and in bottled water and indeed in all water that has suitable nutrients. These organisms cause problems of aesthetic
5 nature in stored water. They form slimy films on water making it unsuitable for drinking. The USEPA has an informal standard of 500 colony forming units of HPC bacteria/ml.
The issues that are relevant with regard to HPC bacteria are
10 relationship between HPC in drinking water and health risks for general public. HPC bacteria can be an indirect indicator of pathogens of concern in drinking water and thus may play a role in assessing the functioning of water purifiers and aesthetic acceptability of water if
15 contaminated with HPC bacteria.
There have been some attempts to reduce and prevent these bacteria from growing in stored purified water.
20 US20030222013, (Yang et.al.,), discloses a drinking water filter capable of inhibiting retrograde bacterial growth at the user outlet with the combination of a non-carbonaceous submicron filter element immediately upstream of the system outlet and a copper orifice element in the outlet downstream
25 of the filter element.
US2005121387, (Alticor Inc) , discloses that copper particles in the carbon filter and the combination of silver treated
30 carbon and copper particles, inhibit growth of bacteria in the filter and the water.
The prior art refers to controlling °HPC bacteria in the filter and during purification but does not provide a disinfectant mechanism for storing water without getting it further contaminated. According to the present invention it
5 is now possible to maintain water sanitised during prolonged storage. It is not linked to the device used for purifying the water that is stored.
It is an object of the invention to maintain water held in a 10 container sanitised during storage.
It is another object of the invention to maintain purified
water sanitised and prevent the growth of HPC bacteria
during the time gap between the purification process and
It is yet another object of the present invention to ensure reduction of microbial counts in slightly impure water.
20 It is yet another object of the present invention to provide a disinfectant means in gravity fed water purification systems to prevent the growth of HPC bacteria during the time gap between the purification process and consumption.
25 SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided a disinfectant unit for water stored in a container, comprising a holder and a halogen source, said halogen source capable of releasing a gaseous disinfectant
30 into the head space of the container through a vent provided in said holder wherein the disinfectant unit is positioned
such that said halogen source is not in contact with the water.
According to another aspect of the present invention there
5 is provided a process for maintaining water held in a container sanitised during storage comprising releasing gaseous disinfectant from a source of halogen into the head space of the container comprising stored water wherein the halogen source is positioned such that it is not in contact
10 with the stored water.
It is particularly preferred that the halogen source is selected from a source of chlorine, bromine or iodine and in particular it is solid source of these materials.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a disinfectant unit for maintaining water held in a container sanitised by releasing gaseous disinfectant into the head space of the container
20 while ensuring the disinfectant is spatially separated from the water to be sanitised.
Thus according to the present invention it is possible to maintain water held in a container sanitised during storage
25 by a process whereby gaseous disinfectant is released into the head space of the container. According to the invention the halogen source of the disinfection unit is not in contact with the stored water. The process is preferably achieved by placing the halogen source in a holder, said
30 source capable of releasing a gaseous disinfectant in to the head space of the container wherein the disinfection unit is
so positioned as to ensure that the halogen source is not in contact with the stored water.
Any water that has to be stored for a given period of time
5 can be kept sanitised by the disinfection unit and by the process described in the present invention. It is particularly useful to keep purified drinking water that is stored sanitised because generally there will be a time gap between the purification process and consumption.
Gravity fed water purification systems are gaining popularity especially in places where there is scarcity of power and running water supply. In these water purification systems also it is quite possible that there is a time gap
15 between the purification process and consumption. In such cases, the disinfection unit and the process according to the invention is useful in maintaining the stored water free of contamination by bacteria especially the HPC bacteria which are so universally prevalent in air and on other
The disinfectant unit is preferably fitted to a gravity fed water purification device comprising .a filtration unit adapted to separate particulate and suspended solids from
25 the input water, which 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
30 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. It is preferable to fit the disinfection unit in such a way that the halogen source capable of releasing a gaseous disinfectant into the head
5 space of the container where the water that exits the scavenger means is collected.
The halogen source is held in a holder provided with a vent
10 to enable the release of the gaseous disinfectant. The halogen source is selected from a source of chlorine, bromine or iodine. It is preferred to use a source of chlorine as the halogen source.. It is preferred that the halogen source is solid. The solid form is preferably
15 powder, granule, tablet or a block. It is particularly preferred that the halogen source is provided as a tablet or a block.
The size of the halogen source is determined by the size of
20 the container and the volume of water that has to be sanitised. It is preferred that the weight of the halogen source is in the range from 2 - 20 g, more preferably 3-12 g and the most preferred range is 5-10 g.
25 The source of chlorine is preferably selected from potassium
dischloroisocyanurate, sodium dichloroisocyanurate,
chlorinated trisodium phosphate, calcium hypochlorite,
lithium hypochlorite, monochloramine, dichloramine,
30 pentaisocyanurate, 1,3 dichloro-5,5-dimethylidanotone, paratoluene sulfodichloroamide, thrichloromelamine, N-
chloramine, N-chlorosuccinimide, N,N'-
dichloroazodicarbonamide, N-chloroacetyl-urea, N,N-
dichloroazodicarbonamide, N-chloroacetyl-urea, N,N-
dichlorbiurile, chlorinated dicyandiamide or a mixture
The concentration of the gaseous disinfectant released from the halogen source in the head space is preferably in the range 0.5 to 5 ppm, more preferably 1 to 3 ppm and most
10 preferably 1 to 2 ppm. It is preferred that the container in which the water is stored is kept covered by a lid to optimise the benefits of the gaseous disinfectant. It is particularly preferred that the container in which the water is stored is a substantially closed system.
The disinfection unit has a holder preferably housing a halogen source and is provided with a vent to allow the passage of the gaseous disinfectant into the head space of
20 the container in which the water is stored. The disinfectant unit is held in the container in such a way that the halogen source is not in direct contact with the water to be kept sanitised.
25 The holder is of any suitable geometric shape and size and designed so as to accommodate it conveniently in the water storage container. The size of the holder depends on the volume of water and the size of the container that has to be sanitised.
The holder housing the halogen source is preferably a hollow cylinder. The holder preferably comprises a base and sidewalls and the vent is provided on the base or sidewalls. It is convenient to provide the vent as slits or holes on
5 the sidewalls. The material used for the construction of the holder is any suitable material that does not chemically react substantially with the halogen source and is selected from polymers used for halogen source storage. The more preferable materials are acrylonitrile butadiene styrene,
10 styrene acrylonitrile or high density polyethylene.
The holder can be fitted on to a container with water which is stationary or in motion.
15 The invention will now be illustrated by the following non-limiting drawing and examples.
Figure 1, shows a perspective view of the disinfection unit which can be fixed inside a container used for storage of
20 water. The disinfection unit has a holder (1), within the hollow space of the holder there is provided an inner support (2) for holding a block of halogen source (3) . The holder is provided with longitudinal slits which act as vents (4) to allow the passage of the gaseous disinfectant
25 into the head space of the container. This disinfection unit can be fitted to any part of the container or the lid of the container in such a way that the halogen source is not in direct contact with the water stored in the container.
i. Growth of HPC bacteria in purified water: Three litres of water purified by various methods described below were stored in closed containers for 0, 2 and 7 days
5 at 25°C. These containers were not air tight containers. The methods used for purifying water in the various experiments were as follows:
Example 1 Example 2 Example 3 Example 4 Example 5
Boiling for 20 minutes
Municipal source which is chlorinated.
Commercially available bottled water
Autoclaved water kept in a sterile
beaker under sterile air condition of a
laminar air flow with 0.22 micron filter
The growth of HPC bacteria was determined by standard microbial plating on R2A agar medium obtained from DIFCO at various time periods. The data is presented in Table 1.
Samples HPC Counts, CFU/ml
0 day 2 day 7 day
Example 1 0 0 10J
Example 2 0 0 55
Example 3 0 0 10*
Example 4 300 10a io4 -
Example 5 0 0 0(Sterile till~ 22 days)
The data presented in Table 1 show that water purified to various levels by various means get contaminated considerably when stored and exposed to external environment. This also indicates atmospheric air becomes
5 major source of HPC contamination in stored water. However, when stored under specific sterile conditions they remain sterile upto about 22 days.
ii. Effect of a halogen source to disinfect stored water:
10 Water was purified using a standard water purification
device and three litres of this water was used for each of
the following study. Purified water was maintained as
control and compared with water that was spiked with HPC
bacteria at 104 CFU/ml. The control and spiked water was
15 kept covered with a lid in a beaker and stored in a closed
condition for 1, 5 and 10 days without exposing to any
gaseous disinfectant. In a similar experiment a 2.5g tablet
of trichloroisocyanuric acid (TCCA) was placed in a
disinfection unit as described in Fig.l, which was attached
20 to the bottom surface of the lid of the container having
water. The various samples tested were as follows:
Example 6 : Purified water without spiking
25 Example 7 : Purified water spiked with 104 CFU/ml
Example 8 : Purified water of Example 6 provided
with a disinfectant unit according to the invention having 2.5g of TCCA.
Example 9 : Purified water of Example 7 provided
with a disinfectant unit according to the invention having 2.5g of TCCA.
Water samples were analysed for microbial contamination at the end of 1, 5 and 10 days by standard method described in Example 1 and the data is presented in table 2.
Sample Counts, CFU/ml
0 day 5 day 7 day
Example 6 0 348 4.2 X 10J
Example 7 110 X 104 2 X 10b 3 X 106
Example 8 0 0 0
Example 9 110 X 104 0 0
10 The data presented in Table 2 show that the gaseous disinfectant released into the head space of the container in which water was stored was effective in controlling the growth of the HPC bacteria. It is also apparent that the disinfectant unit of the invention apart from maintaining
15 the sterile status of purified water also ensures reduction of microbes in slightly impure water.
Dated this 18th day of April 2007
|Indian Patent Application Number||751/MUM/2007|
|PG Journal Number||05/2012|
|Date of Filing||18-Apr-2007|
|Name of Patentee||HINDUSTAN UNILEVER LIMITED|
|Applicant Address||HINDUSTAN LEVER HOUSE, 165-166, BACKBAY RECLAMATION, MUMBAI 400 020|
|PCT International Classification Number||B01D39/02|
|PCT International Application Number||N/A|
|PCT International Filing date|