The document generally relates to an auto shut off system for a water treatment device. Particularly, the document provides an auto shut off system for stopping the flow of water through the device once a predetermined quantity of water has passed through it. The document also provides a water treatment device having such an auto shut off system.

BACKGROUND

Clean potable water is a basic human requirement. However, a large portion of the world's population, especially those living in developing counres do not have access to i. clean potable water.

A number of water treatment devices are well known in the art. Such devices are employed directly in a water system, either in-line or at a terminal end, or in self-contained batch systems. An example of an in-line system is an under-the-counter device which filters water prior to reaching the faucet. Terminal end devices include counter top and faucet mounted filtration systems. Self-contained batch systems include devices such as carafe units.

Typical water treatment devices employ mechanical filtration or chemical treatment. Mechanical filters treat water by preventing passage of particulates and / or bio-organisms. Chemical treatment (e.g., activated carbon-based and ion exchange media) employs processes such as adsorption and ion exchange for removing undesirable chemical species and inactivation of microorganisms. A major drawback associated with chemical treatment is that the chemical media eventually becomes inactive, providing no indication that the useful life of the chemical element has been exhausted. Various methods have been employed to indicate end of life to the user where it is not inherently provided by the behaviour of the filter media. One such means of indicating end of useful life of treatment units is through devices that use a process commonly referred to as "flow totalization". These devices totalize the liquid volume which passes through the treatment media. Both electrical and mechanical "flow totalization" devices are known in the art.

Electrical flow totalization devices employ pressure transducers. The transducers include integrated outputs to calculate total volume. After a predetermined volume has been reached, a valve is electrically actuated to stop the flow.

A mechanical flow totalization device may employ a turbine interconnected with a series of gears. The gears are designed and adapted to mechanically "?dd up" the volume of water passed through the device.

Other mechanical flow totalization devices employ a float mechanism. The float is designed and adapted to rotate a pre-determined distance upon each fill cycle of the water treatment unit. Once that float has made a specific number of rotations and has travelled the complete distance across a support rod, the float rests in a position where it is visible through an opening in housing, indicative of the end of life of the water treatment unit.

Although these devices address the end of life problem, they have drawbacks. Electronic totalizers require batteries as a power source, which are expensive and hence the cost of the totalizing device may become comparable to the purification cartridge itself. On the other hand mechanical totalizers devices are generally complicated and often expensive and fragile. Moreover, these devices are generally in good working condition even after the purification cartridge, in which device is fitted, is exhausted, hence adding to a redundant cost within the purification cartridge. Indian patent application number 917/MUM/2006 discloses a biocide cartridge for purification where the absence of the biocide prevents further flow of water. The device comprises of a container containing a water teachable biocide tablet resting on a base. A movable support having an external arm with a plug is stacked on the biocide tablet, such that as the water teachable biocide tablet is consumed, the movable support descends and at a predetermined end-of-life position the external arm plugs the water outlet, thereby shutting off the flow of water.

However, this device has a number of disadvantages. As the arm and plug in this device are external, this makes the device bulky. Moreover, the external arm and plug are delicate and prone to breakage. As the plug for stopping the flow of water is external, the system is open that may allow dirt and microorganisms to enter into the- pL'rified water. Moreover, the external arm and plug allows for external tampering of the device.

Indian patent application no. 1724/MUM/2009 discloses an auto shut off device for liquids. As illustrated in figure 1, the auto shut off device disclosed therein comprises of one liquid inlet, one liquid outlet and a casing that defines an opening. The device further comprises of a stopper shaped to close the opening and comprises of a top, bottom and side surfaces such that the top surface is positioned within the casing and the bottom surface is positioned outside the casing when the stopper is received in engagement in said opening. The stopper further defines a liquid inlet aperture on the top surface and a liquid outlet aperture on the top surface. The stopper further defines a connecting passage connecting the liquid inlet aperture to the liquid outlet aperture. The stopper further comprises of a liquid inlet passage connecting the liquid inlet to the liquid inlet aperture, and a liquid outlet passage connecting the liquid outlet aperture to the liquid outlet. The device further comprises of a water dissolvable tablet within the casing and configured to rest on the top surface of the stopper. The device further comprises of a plunger resting on the water dissolvable tablet, the plunger including a plug configured to block the liquid inlet aperture and a spring member above the plunger and configured to urge the plunger downwards towards the stopper such that water exiting the liquid inlet aperture impinges on the water dissolvable tablet before entering the liquid outlet aperture.

In this device, water enters through the liquid inlet and rises up through the liquid inlet passage. Once water reaches the liquid inlet aperture of the liquid inlet passage, air in the casing gets trapped within the casing. As the water rises up further in casing, the trapped air in the casing starts getting compressed till the pressure of the compressed air becomes equal to the water pressure at the liquid inlet. This rise in pressure of the compressed air prevents water from rising further up in the casing. Water rises up the liquid inlet passage and impinges onto the bottom surface of the lowermost tablet. The water is diverted by the tablet towards the liquid outlet.

The device disclosed in Indian patent application no. 1724/MUM/2009 suffers from the disadvantage that both air and water are forced to first travel upwards and then downwards. This leads to trapping of air in the casing, which may result in air blockage. This air blockage offers resistance to the flow of water through the auto shut off device causing a drop in pressure head with or without blockage of flow of water.

There is therefore a need for an improved system to stop the flow of water once a predetermined quantity of water has passed through the water treatment device without resulting in air blockage or uneven flow. The system should be simple and compact without any external parts such that the total system is a closed system.

SUMMARY

An auto-shut off system for a water treatment device is disclosed. The auto-shut off system comprises of a casing defining a top edge and a bottom edge; the casing including an inlet configured to receive a water inflow proximate the top edge and an outlet for the water outflow proximate the bottom edge, the casing defining a hollow passage for the unidirectional flow of water under gravity from the inlet to the outlet; a base configured to be received and retained within the casing, the base including a bottom surface and one or more sidewalls extending upward therefrom to define a hollow cavity and forming a rim disposed in contact with the casing, the base further defining an opening at or proximate the bottom surface, the opening in fluid communication with the outlet; at least one water soluble tablet positioned within the hollow cavity and configured to extend above the rim; the water soluble tablet sized smaller than the hollow cavity to define a clearance passage between itself and the base; the clearance in fluid communication with the opening on the base; the water soluble tablet configured to dissolve after contact with a pre-determined quantity of water; and a plunger supported over the water soluble tablet and sized smaller than the casing to define a side channel such that water from the inlet flows via the side-channel to pass through the opening and out of the outlet; the plunger further configured to descend downwards and engage the base on dissolution of the water soluble tablet and close the fluid communication between the inlet and the outlet.

A water treatment device is also disclosed. The water treatment device comprises of a housing including a water filtration system installed therein, the housing defining a chamber therein; an auto-shut off system positioned inside the chamber, including a casing defining a top edge and a bottom edge; the casing including an inlet configured to receive a water inflow proximate the top edge and an outlet for the water outflow proximate the bottom edge, the casing defining a hollow passage for the unidirectional flow of water under gravity from the inlet to the outlet; a base configured to be received and retained within the casing, the base including a bottom surface and one or more sidewalls extending upward therefrom to define a hollow cavity and forming a rim disposed in contact with the casing, the base further defining an opening at or proximate the bottom surface, the opening in fluid communication with the outlet; at least one water soluble tablet positioned within the hollow cavity and configured to extend above the rim; the water soluble tablet sized smaller than the hollow cavity to define a clearance passage between itself and the base; the clearance in fluid communication with the opening on the base; the water soluble tablet configured to dissolve after contact with a pre-determined quantity of water; and a plunger supported over the water soluble tablet and sized smaller than the casing to define a side channel such that water from the inlei flows via the side- channel to pass through the opening and out of the outlet; the plunger further configuredl ^' to descend downwards and engage the base on dissolution of the water soluble tablet and close the fluid communication between the inlet and the outlet.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 illustrates an auto shut off system of prior art; : I

Figure 2 illustrates an auto shut off system in accordance with a preferred embodiment of the present invention;

Figure 3 illustrates a base in accordance with a preferred embodiment of the present invention.

DETAILED DESCRIPTION

For the purpose of promoting an understanding of the principles of the invention, reference will now be made to embodiments and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the disclosed process, and such further applications of the principles of the invention therein being contemplated as would normally occur to one skilled in the art to which the invention relates.

Reference throughout this specification to "one embodiment" "an embodiment" or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrase "in one embodiment", "in an embodiment" and similar language tliroughout this specification may, but do not necessarily, all refer to the same embodiment.

The present disclosure provides an auto-shut off system for a water treatment device. Figure 2 illustrates an auto shut off system (10) fo'r indicating the total amount o water that has passed through a water treatment device ( 12) and stopping further flow of water once the predetermined amount of water has passed through the water treatment device (12). The auto shut off system (10) comprises of a casing (14) and a base (16) including an opening (18). A water soluble tablet (20) is placed in the casing (14) such that it rests on the base (16). A plunger (22) rests on top of the water soluble tablet (20). Water enters the auto shut off system (10) from the top and flows downwards over the water soluble tablet (20) and enters the base (16). The casing (14) defines a top edge (28) and a bottom edge (26); the casing including an inlet (34) configured to receive a water inflow proximate the top edge (28) and an outlet (24) for the water outflow proximate the bottom edge (26), the casing defining a hollow passage (38) for the unidirectional flow of water under gravity from the inlet (34) to the outlet (24); a base (16) configured to be received and retained within the casing (14), the base (16) including a bottom surface (40) and one or more sidew alls (42) extending upward therefrom to define a hollow cavity and forming a rim (30) disposed in contact with the casing (14), the base (16) further defining an opening (18) at or proximate the bottom surface (40), the opening (18) in fluid communication with the outlet (24). The auto-shut off system further comprises of at least one water soluble tablet (20) positioned within the hollow cavity and configured to extend above the rim (30); the water soluble tablet (20) sized smaller than the hollow cavity to define a clearance passage (36) between itself and the base; the clearance (36) in fluid communication with the opening (18) on the base (16); the water soluble tablet (20) configured to dissolve after contact with a pre-determined quantity of water; and a plunger (22) supported over the water soluble tablet (20) and sized smaller than the casing to define a side channel (32) such that water from the inlet flows via the side-channel to pass through the opening (18) and out of the outlet (24); the plunger (22) further configured to descend downwards and engage the base (1 ) on dissolution of the water soluble tablet (20) and close the fluid communication between the inlet (34) and the outlet (24).

In accordance with an embodiment, the sidewalls of the base extend in a taper manner between the bottom surface and the rim.

In accordance with an embodiment, the auto-shut off system includes one or more water soluble tablets stacked on top of each other to vary the allowable predetermined quantity of water before the plunger engages the base.

In accordance with an embodiment, the water soluble tablet (or tablets) is wrapped with parafilm or coated with epoxy resin to control the dissolution of the tablet.

In accordance with a further embodiment, the water soluble tablet(s) is wrapped with parafilm or coated with epoxy resin such that at least one surface of the tablet is exposed to water for dissolution.

Referring to figure 2, the base (16) has an opening (18) for water to pass out of the base (16) and out of the auto shut off system (10). The opening (18) may be positioned either on the bottom surface (40) or on the sidewalls (42) of the base (16). Referring to figure 3, the opening (18) is of two parts with the first part located on the sidewalls (42) and the second part located on the bottom surface (40). The first part and the second part are in fluid communication with each other. Alternatively, the opening (18) of the base is located such that it extends partially on the sidewall (42) and partially on the bottom surface (40). Preferably, the opening (18) is positioned on the bottom surface (40) to aid the unidirectional flow.

In accordance with an embodiment, the bottom surface of the base includes serrations extending upwards to hold and locate the water soluble tablet within the hollow cavity. The number of water soluble tablets provided in the casing (14) depends on the desired end of life and the solubility of the tablet. The water soluble tablet is made of a chemical having low solubility in water. The water soluble tablet includes but ϋ not limited to tablet composed of CaS04.2H20, CaO or MgO.

In accordance with an embodiment, the water soluble tablet is made of CaS0 ₄ .2H ₂ 0 by adding and mixing water to CaS0 ₄ .2H ₂ 0 and compressing the mixture in a pressure die. The amount of CaS0 ₄ .2H ₂ 0 per tablet may vary from lgm to lOOgm. Specifically the amount of CaS0 ₄ .2H ₂ 0 per tablet may be lOgm. The proportion of water to CaS0 ₄ .2H ₂ 0 may vary from 0 to 50% and is preferably 20%. The compression pressure may vary from 0 to 50 tons and is preferably 8 tons.

The plunger (22) is in the form of a disk or plate that is sized to fit within the casing (14) with a clearance to form a side-channel (32) that enables water from the top to flow down towards the base (16). In the embodiment illustrated the plunger (22) is a cylindrical shaped component. The plunger (22) is configured to be received by the base (16) and block the flow of water through the auto shut off system once the tablets dissolve by a predetermined amount by water. Preferably, the plunger is configured to engage the rim (30) of the base (16) to provide a simple and reliable auto-shut off. In accordance with an embodiment, surface of the plunger which is configured to engage the rim (30) as well as the rim (30) are provided with gaskets to accommodate any variation in size of the plunger or the rim upon engagement thereof. Such gaskets facilitate complete blockage of the flow of water through the side channel (32) and provides reliable auto-shut off. In accordance with an embodiment, the gaskets are made up of plastic or rubber. By way of specific example, the gaskets are made up of silicon rubber.

In accordance with an aspect, the plunger may provide a visual indicator of the amount of water that has passed through the water treatment device. The casing of the auto-shut off system may be completely transparent for visual inspection f the plunger or may have a transparent column along a selected portion. The plunger may be a brightly colored component. Alternatively, a separate indicator in the form of a bright coloring or tape may be provided on the periphery of the plunger. The plunger or the indicator may be visually inspected to determine the level of the water soluble tablets remaining in the casing of the auto shut off system. Alternatively, the casing may be provided with a transparent window for visual inspection of the plunger or the indicator when the plunger is at or close to the end-of-life position. In accordance with an embodiment, the casing may also be provided with marking that indicates the amount of water that has passed through the water treatment device. The casing includes a scale such that a relative position of the plunger with respect to the scale indicates a measure of the quantity of water that has passed through the casing.

In accordance with an aspect, a biasing means is provided between the plunger and the top edge of the casing such that the plunger is biased to descend downward inside the casing. The biasing means include spring and bellow. By way of example, a spring may be provided between the plunger (22) and the top edge (28) of the casing (14) as seen in figure 2. The spring provides an additional downward force to the plunger (22) ensuring that it descends tlirough the casing (14) as the water soluble tablets (20) are dissolved by water.

The dissolution of water soluble tablets relates to the amount of water passed through the water treatment device. The plunger or any indicator attached to it incrementally moves down as the water soluble tablets dissolve indicating the cumulative amount of water passed. After the passage of a predefined amount of water through the water treatment device the water soluble tablets are configured to dissolve. Once the water soluble tablets (20) dissolve by a predetermined amount by water, the spring forces the plunger (22) onto the base (16). This shuts off the flow of water through the water treatment device (12).

The auto shut off system (10) is vertically oriented and allows unidirectional flow of water from the top to bottom of the water treatment device. In accordance witli a preferred embodiment, the outlet (24) of the auto shut off system (10) is made sufficiently wi de to ensure smooth exit of water and avoid any air bubble or water film formation.

The disclosure also provides a water treatment device comprising a housing including a water filtration system installed therein, the housing defining a chamber therein and the auto-shut off system, as disclosed above, inside the chamber. The water filtration system may include any conventionally available water filtration system, preferably a cartridge as disclosed in Indian patent application no. 2807/MUM/2009 which is incorporated herein by reference.

SPECIFIC EMBODIMENTS ARE DESCRIBED BELOW

An auto-shut off system for a water treatment device, comprising a casing defining a top edge and a bottom edge; the casing including an inlet configured to receive a water inflow proximate the top edge and an outlet for the water outflow proximate the bottom edge, the casing defining a hollow passage for the uni-directional flow of water under gravity from the inlet to the outlet; a base configured to be received and retained within the casing, the base including a bottom surface and one or more sidevvalls extending upward therefrom to define a hollow cavity and fonning a rim disposed in contact with the casing, the base further defining an opening at or proximate the bottom surface, the opening in fluid communication with the outlet; at least one water soluble tablet positioned within the hollow cavity and configured to extend above the rim; the water soluble tablet sized smaller than the hollow cavity to define a clearance passage between itself and the base;, the clearance in fluid communication with the opening on the base; fee water soluble tablet configured to dissolve after contact with a pre-determined quantity of water; and a plunger supported over the water soluble tablet and sized smaller than the casing to define a side channel such that water from the inlet flows via the side-channel to pass through the opening and out of the outlet; the plunger further configured to descend downwards and engage the base on dissolution of the water soluble tablet and close the fluid communication between the inlet and the outlet.

Such auto-shut off system(s), wherein the sidewalls are extending in a taper manner between the bottom surface and the rim.

Such auto-shut off system(s), wherein the opening of the base is located such that it extends partially on the sidewall and partially on the bottom surface.

Such auto-shut off system(s), wherein the opening comprises of a first part and a second part in fluid communication with each other, the first part located on the sidewall and the second part located on the bottom surface.

Such auto-shut off system(s), wherein the bottom surface includes serrations extending upwards to hold and locate the water soluble tablet within the hollow cavity. Such auto-shut off system(s), wherein the plunger is biased to descend downward inside the casing by a biasing means.

Such auto-shut off system(s), including two or more water soluble tablets stacked on top of each other to vary the allowable predetermined quantity of water before the plunger engages the base.

Such auto-shut off system(s), wherein the casing includes a scale such that a relative position of the plunger with respect to the scale indicates a measure of the quantity of water passed through the casing.

FURTHER SPECIFIC EMBODIMENTS ARE DESCRIBED BELOW

A water treatment device, comprising a housing including a water filtration system installed therein, the housing defining a chamber therein; an auto-shut off system positioned inside the chamber, including a casing defining a top edge and a bottom edge; the casing including an inlet configured to receive a water inflow proximate the top edge and an outlet for the water outflow proximate the bottom edge, the casing defining a hollow passage for the uni-directional flow of water under gravity from the inlet to the outlet; a base configured to be received and retained within the casing, the base including a bottom surface and one or more sidewalls extending upward therefrom to define a hollow cavity and forming a rim disposed in contact with the casing, the base further defining an opening at or proximate the bottom surface, the opening in fluid communication with the outlet; at least one water soluble tablet positioned within the hollow cavity and configured to extend above the rim; the water soluble tablet sized smaller than the hollow cavity to define a clearance passage between itself and the base; the clearance in fluid communication with the opening on the base; the water soluble tablet configured to dissolve after contact with a pre-determined quantity of water; and a plunger supported over the water soluble tablet and sized smaller than the casing to define a side channel such that water from the inlet flows via the side-channel to pass tlirough the opening and out of the outlet; the plunger further configured to descend downwards and engage the base on dissolution of the water soluble tablet and close the fluid communication between the inlet and the outlet.

INDUSTRIAL APPLICABILITY

The auto shut off system 10 disclosed indicates the amount of water that has passed through a water treatment device and stops further flow of water once the predetermined amount of water has passed through. The auto shut off system 10 as disclosed is simple, closed, compact, accurate and reliable. It is inexpensive and easy to manufacture. The specific configuration of the auto-shut off system and in particular the positioning of the opening on the base; the positioning of the water soluble tablet within the base; size of the water soluble tablet being smaller than the base; and the unidirectional flow from top to bottom under gravity provide a simple and reliable solution. The smaller size of the bottom surface viz-a-viz the rim, which may be achieved by the tapered sidewalls, also ensure that not only the water is directed towards the tablets but also enable a larger opening 18 to be formed on the base.