Device for dispensing a unit-dose of disinfecting agent

Field of the invention

The present invention relates to a device for disintegrating and dispensing a unit-dose of disinfecting agent for use in a water purifier. The invention further relates to a water purification device comprising said device for disintegrating and dispensing a unit-dose of disinfecting agent, which is capable of regulated and controlled discharge of a pre-determined dose of any water-soluble disinfecting material into a batch of water.

Background and Prior art

There are various devices known and in use for household disinfection of drinking water. In most of these devices, calcium hypochlorites, chloro- isocyanurates etc. in the form of pellets or tablets are used for chlorinating or treating water. These tablets or pellets generate chlorine when they come in contact with water which kills the microorganisms present in the water, thus purifying the water and making it safe for drinking. Some of the materials used to make the tablets or pellets or such unit-doses do not easily dissolve in water and need to be disintegrated into nearly powder form to facilitate dissolution. Thus, while on the one hand such compact unit-doses are desirable from the standpoint of ease of handling and availability of controlled dosage amounts, it is sometimes difficult to ensure quick dissolution of these unit-doses when dropped into a batch of water and therefore they require to be disintegrated when added to water that has to be purified.

For a long time mortar and pestle units have been used to crush tablets and such unit-doses. The drawback associated with such an approach to crushing is that the tablet or a portion thereof may escape from the mortar especially under impact from the pestle, thereby causing insufficient dosing. The crushed powder may stick to the inside surface of the mortar, which need to be scraped

out consuming additional time and effort and concomitant danger of contamination while failure to do so may lead to reduced dosage.

GB 2327093 combines a detergent tablet and a dispensing device to disperse a tablet in an aqueous medium, the device at least partially being formed from a flexible, water permeable material. This device is not suitable for use in a water purification device.

EP1072716 discloses a device for controlling the dispersion characteristics of a tablet, the device comprising a first region which is housed inside the device and contains the tablet, as well as a second region which is outside the device. The characteristic of the device is to allow controlled dispersion of the tablet by means of a separation between a first region and a second region. The device disclosed is not suitable for the release of a disinfecting tablet into water. Further, the device cannot be housed inside a water purification system and is thus not suitable for water disinfection purposes.

WO 98/40550 discloses a device to disperse a detergent tablet comprising a sleeve having at least one opening to insert the tablet, the sleeve being at least partially formed from a water permeable material, the tablet fitting loosely in the sleeve. However such devices typically comprise a closing means in order to prevent the tablet from escaping from the device during the wash, such closing means rendering the manufacture of the device and its use more complex. Further, the device is not suitable for use in a water purification device.

EP 1072715 discloses a device to disperse a detergent tablet, the device comprising a sleeve having at least one opening to insert the tablet, the sleeve being at least partially formed from a water permeable material, the tablet fitting loosely in the sleeve, characterized in that the sleeve has length and flexibility which prevents the tablet escaping from the sleeve during a normal wash operation. Moreover, this device comprises a very long sleeve, which being flexible would be very cumbersome to be included and used in a tablet dispensing device housed within a water purification system.

In conventional candle type domestic water filters, disinfecting tablets are manually added to filtered or unfiltered water. Such manual addition while being very disadvantageous, cumbersome and unfriendly from the user point of view, does not seek to solve the problem of quick dissolution of difficult to dissolve unit-doses of disinfecting material. Thus a need exists for a device for dispensing disinfecting material in unit-doses e.g tablets in a water purification device in a crushed form to overcome the problems associated with the prior art.

In our co-pending application 43/MUM/2005, there is disclosed a tablet dispensing device for use in a water purification device in which unit-doses of the disinfecting material are delivered into the water in the unit-dose form itself. Such a device is useful for easy-to-disperse and dissolve material but would be not so effective when difficult to disperse and dissolve materials are used.

Summary and objects of the invention

It is an object of the invention to provide for a device for dispensing unit-doses of disinfecting material in a water purification device in a disintegrated form.

Another object of the invention is to provide water purification device comprising a unit-dose disintegrating and dispensing device device and that can store multiple unit-doses of water disinfecting material and release one or more units of the same into a batch of water in the water purification device when required.

A further object of the present invention is to provide a water disinfection device, which is portable and inexpensive and provides for fast and easy generation of disinfected water and in which disinfecting agents are not required to be manually added.

Yet another object of the present invention is to provide a disinfecting device in which a pre-determined unit-dose of any sparingly soluble disinfecting material

in the form of a tablet or pill or similar form is released in a crushed or small particulate form or similar disintegrated form into a batch of water, thus enhancing the dissolution rate of the disinfecting material.

Description of the invention

For the purposes of this invention a unit-dose is defined as a single dose of disinfectant in a solid shaped form, such as a tablet or pill or a capsule filled with powder or fluid, that is suitable for disinfecting a predefined batch of water.

In one aspect the invention provides a unit-dose disintegrating and dispensing device for dispensing disinfectant in water, comprising:

(a) a container having a base provided with a unit-dose dispensing aperture; (b) said aperture being provided with a plurality of tabs that are capable of supporting a unit-dose

(c) a cam-operated unit-dose disintegrating and dispensing mechanism disposed in said container, said mechanism comprising: (i) a handle for driving the cam (ii) a cam-driven shaft capable of rotational and axial motion along its own axis; (iii) an open-ended column for holding a stack of unit-doses of disinfecting material, said column offset from and attached to said shaft and capable of being rotated on rotation of said shaft (iv) a crushing arm offset from and attached to said shaft and capable of rotation around the axis of said shaft and capable of axial motion parallel to the axis of said shaft, such that at one position at which said column is aligned with said aperture, only one unit-dose is released from said column and held on said tabs, and on driving said cam, at the disintegrating and dispensing position, said crushing arm aligns with and axially pressurizes said unit- dose against said tabs thereby disintegrating the unit-dose to dispense it from said container.

According to another aspect of the invention there is provided a water purification device comprising:

(a) an upper chamber comprising an inlet means for receiving input water and a lower chamber comprising an outlet means for collecting purified water; said upper chamber in fluid communication with

(b) a filter medium for removing suspended particulates and dissolved organics; and

(c) said unit-dose disintegrating and dispensing device; such that when feed water is fed into the upper chamber, the water is filtered through said filter medium and fed into the lower chamber where the water is disinfected by the unit-dose of disinfectant dispensed from said unit-dose disintegrating and dispensing device.

It is desirable that the disinfected water from the lower chamber passes through a scavenger means to remove any disinfection byproducts that may be present in the water.

The unit-dose disintegrating and dispensing device comprises a container which has a cam-operated unit-dose disintegrating and dispensing mechanism. The container may be of any shape suitable for housing the mechanism. A cylindrical shape is very suitable for most cases. The base of the container has an aperture whose cross-section corresponds to the shape of the unit-dose to be dispensed. Thus, if the unit-dose to be dispensed has a circular cross- section, the aperture is constructed to have a circular cross-section. The aperture is provided with tabs which are so configured that they can hold the unit-dose and prevent it from being dispensed straight into the water without being disintegrated. When a certain amount of pressure is applied on the unit- dose, e.g through axial force through a crushing arm, the compressive force on the unit-dose between the crushing arm and the tabs, causes the unit-dose to disintegrate and pass through below the tabs.

In one particular embodiment the aperture is configured such that the unit-dose to be dispensed passes through it. The tabs are provided below the bottom surface of the base and are so configured that the unit-dose dispensed through the aperture is held on the tabs.

The unit-dose disintegration and dispensing mechanism has a shaft which is preferably cylindrical. The shaft is driven by a cam mechanism and is capable of rotational and axial motion along its own axis. The shaft is preferably disposed in the centre of said container. The rotatable shaft is also attached to a column which is offset from said shaft. The column is capable of containing a stack of the tablets to be dispensed and is open on both ends. The upper end facilitates addition of fresh unit-doses while the lower end enables dispensing of them into the water when the cam is actuated. The shaft comprises a handle for driving the cam. The disintegrating and dispensing mechanism comprises a crushing arm offset from and attached to said shaft and capable of rotation around the axis of said shaft and capable of axial motion parallel to the axis of said shaft. In the embodiment where the unit-dose is held on the tabs below the aperture, it is desirable that the crushing arm has a cross-section marginally smaller than the aperture such that the crushing arm is capable of passing through it. Optionally a means to resiliently bias the position of the column from the disintegrating and dispensing position to the position at which the column is aligned with the aperture, may be provided e.g a spring.

The unit-doses, e.g. tablets, may be made from any chlorine releasing material e.g. potassium or sodium dichloroisocyanurate, trichlorocyanuric acid, chlorinated trisodium phosphate, calcium hypochlorite, lithium hypochlorite, monochloramine, dichloramine, [(monotrichloro)-tetra(monopotassium dichloro)] pentaisocyanurate, 1,3 dichloro-5,5-dimethylhydantoine, N-chloro-paratoluene sulfonamide, trichloromelamine, N-chloramine, N-chlorosuccinimide, N ₁ N'- dichloroazodicarbonamide, N-chloroacetyl-urea, N.N-dichlorbiurile, chlorinated dicyandiamide. The disinfectant is preferably non-hygroscopic. In cases where the material is hygroscopic, a dessicating material may be provided in the

column where the unit-doses are stacked which preferentially absorbs the moisture thereby maintaining the purity and integrity of the unit-doses.

The water purification device of the invention comprising the unit-dose disintegrating and dispensing device has a filter medium. The filter medium is so disposed in the purification device such that water fed in to the upper chamber flows through said filter medium into said lower chamber. The filter media which may be used include sediment filters which may be woven or non- woven cloth, granular adsorbent media e.g clay or activated carbon or combinations thereof. When particulate activated carbon is used, it may be bonded into a block or unbonded. When bonded, the preferred binding agents include polymers, e.g high molecular weight polyethylene. The filter medium facilitates removal of suspended particulates and dissolved organic compounds like pesticides and pesticide residues. When bonded into a block, the block may be used to remove particulates generally above 3 micrometer in size including chlorine resistant microorganisms like cysts.

The water thus free of the dissolved and suspended impurities is collected in the lower chamber where the disinfecting agent is dispensed by the unit-dose disintegrating and dispensing device, thus killing micro-organisms like viruses and bacteria.

The water may then optionally pass through a scavenger means before exiting the water purification device. The scavenger means separates the excess disinfectant and its byproducts from the water, thus making it suitable for drinking. The scavenger means is preferably bacteriostatic activated carbon.

The water may flow through the scavenger means in the downward direction or in the upward direction. Various embodiments may be envisaged for such flow, including the one described in WO04014803. It is preferred that the volume of water collected post the scavenger means in for example, a collection chamber is kept to a minimum. A particularly preferred embodiment of this is to have the water post the scavenger means directly connected to an outlet means e.g. a

tap so that water is in contact with the disinfecting agent for the longest time possible and is dispensed for use through the scavenger means only on opening the tap.

Drawings

The invention will now be illustrated with reference to a non-limiting exemplary embodiment in the drawings wherein:

Figure 1 is a perspective view of a tablet disintegrating and dispensing device with the column aligned with the aperture on the bottom plate;

Figure 2 is a perspective view of the tablet disintegrating and dispensing device with the crushing arm aligned with the aperture;

Figure 3 is a schematic of a water purification device comprising the tablet disintegrating and dispensing device.

Figure 1 :

The column (1 ) for holding the stack of tablets (2) is attached to the shaft (3) with the plate (4) and with support plate (5). The column is open on both the bottom end (6) and the top end (7). The cam-operated unit-dose disintegrating and dispensing mechanism is disposed in container (8). The container has aperture (9) on the bottom plate (10). The shaft is driven by a cam provided with a handle (11) to enable rotational (R) and axial (A) motion of the shaft along its own axis. The aperture is provided with tabs (12) attached to the bottom of the base. The thickness of the base and the configuration of the tabs are such that in the position indicated in Figure 1 , only one unit-dose passes through the aperture and is held on the tabs. A crushing arm 13 is configured parallel to the shaft and downwardly with respect to the support plate 5.

Figure-2: The aperture (9) in the base is aligned with the crushing arm (13). When the tablet is desired to be dispensed into the water, the handle (11) is moved along the slit (14) from position (a) to position (b), to bring the crushing arm (13) in line with the aperture (9). Further movement of the handle from position (b) to

position (c) causes the crushing arm (9) to force the tablet against the tabs (12) causing the tablet to disintegrate, thereby being dispensed from the disintegrating and dispensing device.

Figure-3:

The water purification device comprises the container (8) having the tablet disintegration and dispensing device. The water purification device (15) has an upper chamber (16) and a lower chamber (17). Water is fed into the water purification device through inlet means (18). The feed water is filtered first through a sediment filter (19) which is cup shaped and made of non-woven cloth and collects in the upper chamber. The water then passes through filter medium (20) which is a block made of activated carbon, to make the water free of dissolved organics, particulate matter with a size greater than 3 microns, and biologically active organisms like cysts. The water then flows through tube (21) and downcomer (22) into the bottom chamber. When the water flows through the downcomer, the tablet disintegration and dispensing device is actuated to dispense one disinfectant tablet into the bottom chamber also through the downcomer (22). The tablet dissolves in the water in the bottom chamber, thus generating the active biocide e.g. chlorine thereby killing the microorganisms like virus and bacteria. When the water reaches a level higher than the height h, the water then flows through the scavenger means (23) e.g. a bed of bacteriostatic granular activated carbon in the downflow direction into collection chamber (24). The bed of granular carbon adsorbs the residual chlorine in the water and any by products generated as a result of the biocide dissolution in water e.g. cyanuric acid as a byproduct when sodium di chloro iso cyanurate is used as the biocide. The water is dispensed from the outlet means (25).

The present invention thus provides a simple portable and convenient unit-dose disintegration and dispensing device that can store multiple units of disinfecting material and release one or more single units into a batch of water in a water purification device as and when required.