WO2013046215A1

WO2013046215A1 - Device for dosing of chemicals

Info

Publication number: WO2013046215A1
Application number: PCT/IN2012/000403
Authority: WO
Inventors: Dilshad Ahmad
Original assignee: Tata Consultancy Services Limited
Priority date: 2011-09-20
Filing date: 2012-06-07
Publication date: 2013-04-04

Abstract

The subject matter described herein relates to a device (104) for dosing of a chemical in a liquid is described. The device (104) includes a dosing unit (116) and a fluid chamber (118) coupled to the dosing unit (116). The fluid chamber (118) is configured to receive the liquid and comprises a regulating means configured to regulate a level of the liquid in the fluid chamber (118). The dosing unit (116) is configured to release a predetermined amount of the chemical in the liquid flowing through the fluid chamber (118) when the liquid reaches a predetermined level to come in contact with a bottom contact surface of the dosing unit (116).

Description

DEVICE FOR DOSING OF CHEMICALS TECHNICAL FIELD

[0001] The present subject matter relates, in general, to dosing of a chemical in a liquid and, in particular, to a device for automatic dosing of the chemical into the liquid.

BACKGROUND

[0002] Liquids, such as water, have been consistently used in various industrial as well as household processes for varying purposes, such as for drinking, cleaning, bathing, and construction. These processes usually require enhancing the quality of the liquid to achieve better results by, for example, adding chemicals. For instance, drinking water may be purified by adding various chemicals, such as chlorine, aluminum hydroxide, and magnesium oxide to make the water suitable for drinking. Similarly, chlorine may be added to water in swimming pools. In another example, chemicals such as detergents are added in water to facilitate efficient washing of clothes, for example, in households or laundry industry.

[0003] Further, in order to achieve a desired result, the amount of chemical added in the liquids is usually controlled. Consistent and controlled dosing of chemicals in a liquid is thus of both domestic and industrial importance. Typically, the chemical is dosed in the liquid using dosing devices configured to dose a controlled amount of the chemical in the liquid. The dosing devices generally include various electrical components, such as water pumps, solenoid valves, and controllers, and are thus costly and also bulky in size. Further, using the electrical components also leads to an increase in operational and maintenance costs as these electrical components usually require regular maintenance.

SUMMARY

[0004] This summary is provided to introduce concepts related to a device for dosing of a chemical in a liquid, which is further described below in the detailed description. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.

[0005] In one embodiment, a device for dosing of a chemical in a liquid is described. The device includes a fluid chamber and a dosing unit coupled to the fluid chamber. The fluid chamber is configured to receive the liquid and comprises a regulating means configured to regulate a level of the liquid in the fluid chamber. The dosing unit is configured to release a predetermined amount of the chemical in the liquid when the liquid flowing through the fluid chamber reaches a predetermined level to come in contact with a bottom contact surface of the dosing unit

BRIEF DESCRIPTION OF DRAWINGS

[0006] The detailed description is provided with reference to the accompanying figures.

In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and components.

[0007] Figure 1 illustrates an apparatus for dosing a chemical into a liquid, according to an embodiment of the present subject matter.

[0008] Figure 2 illustrates a device for dosing a chemical into a liquid, according to a first embodiment of the present subject matter.

[0009] Figure 3 illustrates a device for dosing a chemical into a liquid, according to a second embodiment of the present subject matter.

[0010] Figure 4 illustrates a device for dosing a chemical into a liquid, according to a third embodiment of the present subject matter.

[0011] Figure 5 a device for dosing a chemical into a liquid, according to a fourth embodiment of the present subject matter.

[0012] Figure 6 illustrates a graph depicting performance of a device for dosing a chemical into a liquid, in accordance with the first embodiment of the present subject matter.

[0013] Figure 7 illustrates a graph depicting performance of the device, in accordance with the fourth embodiment of the present subject matter.

DETAILED DESCRIPTION

[0014] Devices and methods for dosing of a chemical into a liquid, such as water, are described herein. Dosing of chemicals into water is of importance in various industrial and domestic applications. For example, water available from natural sources is usually treated by adding a controlled amount of chemicals with the help of a dosing mechanism in order to make the water potable. Laundry industry also requires a controlled concentration of detergents to be dosed into the water to have efficient washing of clothes.

[0015] Continuous dosing of chemical in a controlled way is similarly required for various other commercial and household purposes, such as in water desalination plants. Similarly, in swimming pools, it is generally desirable to obtain controlled dosing of chlorine to the water flowing into the swimming pools. Additionally, many adsorption based water purification techniques require conditioning of water pH before adsorption of the chemical on to an adsorption column. Further, pH control of the water is also an important aspect of producing potable water, which is generally controlled by adding a controlled amount of a suitable chemical with the help of a dosing mechanism.

[0016] Controlled dosing of chemicals in water is thus of high importance, and various methods and systems have been employed to dose the chemicals into water. Typical dosing devices include various electrical components such as water pumps, solenoid valves, and controllers, and are thus costly and also bulky in size. Other conventional devices use microprocessors, such as sensors, to measure a concentration of chemicals in the water and a circuitry to control a dosing rate of the chemical based on the concentration. Similar controlled dosing devices may also be used for adding chemicals to other liquids, for example, while adding additives to crude oil and petroleum products.

[0017] Using such complex devices for dosing the chemicals usually involves high installation charges and requires regular maintenance, thus increasing the operational and maintenance costs of these devices. Other conventional methods usually require maintaining a desired pressure of flowing liquid while dosing the chemical into the liquid. Such methods may thus be less effective if there is a loss in pressure.

[0018] Device(s) for dosing of a chemical into a liquid are described herein. According to an embodiment of the present subject matter, an apparatus for dosing chemicals into a liquid includes a dosing device, interchangeably referred to as a chemical doser, with an inlet and an outlet. The inlet is used for receiving a liquid such as water from one or more water sources. In one implementation, the inlet may be connected to a reservoir of the liquid. The liquid is subsequently received by the chemical doser for dosing the chemical. Dosed liquid, i.e., liquid dosed with a chemical, exits from the chemical doser through the outlet. The chemical doser releases a controlled amount of the chemical at a predetermined rate so as to ensure that the concentration of the chemical is maintained in a predetermined range in the dosed liquid. For ease of explanation, and not as a limitation, the explanation of the embodiments will be provided with respect to the liquid being water. However, it will be understood that embodiments and implementations described herein can be used for controlled dosing of any suitable chemical in any liquid.

[0019] In one embodiment, the chemical doser includes a dosing unit, a fluid chamber, and a mixing chamber. The dosing unit is configured to store and release a predetermined amount of the chemical into the water to receive dosed water, i.e., water dosed with a chemical. The fluid chamber is coupled to the dosing unit and is configured to regulate the level of the water so as to ensure that the concentration of the chemical is maintained in a predetermined range in the dosed water for variable flow of water through the chemical doser.

[0020] In operation, the water to be dosed with the chemical first enters into the fluid chamber. Depending upon the flow rate of the water the fluid chamber regulates the level of the water such that at a predetermined level the water comes in contact with a bottom contact surface of the dosing unit. On establishment of the contact between the bottom contact surface and the water, the dosing unit begins dosing of the chemical into the water. The water along with the chemical subsequently exits the fluid chamber and enters the mixing chamber, where the chemical is uniformly mixed with the water to achieve uniform concentration of the chemical in the dosed water coming out of the water mixing chamber. Once the outflow of the water from the fluid chamber matches with the inflow of the water, water level attenuates to a predetermined value ensuring that a predetermined amount of the chemical is being mixed with the water. With increase in flow rate of water, the water level in the fluid chamber also rises, which in turn increases an amount of the chemical dosed by the dosing unit.

[0021] As soon as the inflow of the water decreases, the water level in the fluid chamber falls below the predetermined level. The dosing unit and the water are thus no more in contact due to which the dosing unit stops the dosing of the chemical in the water. The dosing unit is thus configured to dose the chemical in accordance to the flow rate of the water and stops the dosing in absence of or in case of a decrease in the flow rate of the water. Additionally, the dosing unit doses the chemical into the water with variable flow rate so as to maintain a predefined concentration of the chemical into the dosed water irrespective of the flow rate of the water entering the fluid chamber.

[0022] These and other advantages of the present subject matter would be described in greater detail in conjunction with the following figures. While aspects of described systems and methods for dosing of chemicals in water can be implemented in any number of different dosing devices, the embodiments are described in the context of the following exemplary device(s).

[0023] Figure 1 illustrates an apparatus 100 for dosing a chemical into a liquid, according to an embodiment of the present subject matter. In said embodiment, the apparatus 100 includes a source container 102 for storing liquid, such as water that needs to be mixed with the chemical, a dosing device 104 for dosing the chemical in the liquid to provide dosed liquid, and a collection container 106 for receiving the dosed liquid. In one implementation, the dosing device 104 may be connected to the source container 102 in a leak proof manner. Further, the chemical may be any of a hygroscopic chemical, a non-hygroscopic chemical, a crystalline chemical, and an amorphous chemical. Examples of the chemical include, but are not limited to, an aluminium salt, such as aluminium acetate, aluminium chloride, aluminium hydroxide, aluminium sulphate, aluminium nitrate, and aluminium carbonate, or an iron salt, such as ferric bromide, ferrous carbonate, ferrous chloride, ferrous hydroxide, ferrous sulphate, ferrous oxalate, ferric sulphate, and ferric chloride. Further, the chemical used for dosing can also be used in the form of a chemical composition, such as a mixture of two or more of the aforementioned chemicals, a detergent composition, a pH conditioner, and a water softener. For ease of explanation, and not as a limitation, the explanation of the embodiments will be provided with respect to the liquid being water. However, it will be understood that embodiments and implementations described herein can be used for controlled dosing of any suitable chemical in any liquid.

[0024] Water from any source, such as ground water and other surface water sources may be poured in to the source container 102 through a water inlet 108 for mixing with the chemical for various household and industrial purposes, such as purification. The water from the source container 102 then enters the dosing device 104 as shown by an arrow 1 10. The dosed water, having the chemical mixed in a predetermined amount may then flow into and get collected in the collection container 106 as shown by an arrow 1 12. In an embodiment, the collection container 106 is provided with an outlet, such as a tap 114 from which the purified water may be drawn for consumption. Additionally the dosing device 104 can be used for dosing chemicals in water running in a passage without altering pressure and flow rate of the running water.

[0025] In one embodiment, the dosing device 104, interchangeably referred to as the chemical doser 104 includes a dosing unit 116, a fluid chamber 118, and a mixing chamber 120. The dosing unit 116 is configured to store and release a predetermined amount of the chemical into the water to receive the dosed water. In one implementation, the dosing unit includes a chemical storage (not shown in this figure) to store the chemical and a doser (not shown in this figure) coupled to the chemical storage to receive the chemical from the chemical storage and release the chemical in the water. The fluid chamber 1 18 is coupled to the dosing unit 1 16 and is configured to ensure regular dosing of the chemical in the dosed water for variable flow and pressure of water through the chemical doser 104. The fluid chamber 118 includes a breathing mechanism (not shown in this figure) to maintain uniform pressure inside the dosing unit and a regulating means (not shown in this figure). The regulating means is configured to regulate the level of the water such that at a predetermined level the liquid comes in contact with the dosing unit 1 16 to receive the predetermined amount of the chemical. Water from the fluid chamber 118 along with the chemical dosed by the dosing unit 116 is subsequently received by the mixing chamber 120. In the mixing chamber 120, the chemical is mixed with the water so as to achieve a uniform concentration of the chemical in the dosed water coming out of the mixing chamber 120 and into the collection container 106.

[0026] In operation, as the water enters into the chemical doser 104 the water initially gets collected in the fluid chamber 1 18. As the water starts collecting, the water level (not shown in the figure) increases inside the fluid chamber 118 and starts touching a bottom contact surface (not shown in the figure) of the chemical doser 104, making the chemical doser 104 release the chemical. With the increase of the water level, the regulating means starts draining out the water along with the chemical from the fluid chamber 118 to the mixing chamber 120 to regulate the predetermined level of the water in the fluid chamber 118. With further increase of the water level, outflow of the water and the chemical in the mixing chamber 120 also increases. Once the outflow of the water, through the regulating means, matches with the inflow of the water in the fluid chamber 118, the water level attenuates to a predetermined level ensuring that a predetermined amount of the chemical is mixed with the water. As the rate of inflow further increases, the water level further increases inside the fluid chamber 118. At this point the water starts entering the dosing unit 1 16, thus increasing the surface of the dosing unit 1 16 in contact with the water, which in turn increases the amount of the chemical dosed in the water. Rate of flow of water entering the fluid chamber 118 thus controls the increase of water level and in turn the amount of the chemical dosed in the water.

[0027] Further, with the decrease in the inflow of the water, the water level in the fluid chamber 1 18 falls below the predetermined level. The water thus stops touching the bottom contact surface of the dosing unit 116 due to which the dosing unit 116 stops the dosing of the chemical in the water. The dosing unit 1 16 is thus configured to dose the chemical in accordance to the flow rate of the water and stops the dosing in absence of or in case there is a substantial decrease in the flow rate of the water. Additionally, the dosing unit 1 16 doses -the chemical into the water with variable flow rate so as to maintain a the concentration of chemical into the dosed water in a predetermined range irrespective of the flow rate of the water entering the fluid chamber 118.

[0028] Figure 2 illustrates components of the chemical doser 104 for automatic and metered dosing of a chemical into a liquid, according to a first embodiment of the present subject matter. As previously discussed, the chemical doser 104 includes the dosing unit 1 16, the fluid chamber 1 18, and the mixing chamber 120. In said embodiment, the dosing unit 116 includes a chemical cartridge 202, as a chemical storage, containing the chemical, and a doser 204 to release a predetermined amount of the chemical into the liquid. Although the Figure 2 has been described in considerable detail with respect to water, it will be understood that the chemical doser 104 can be used to dose a chemical in any liquid.

[0029] In one embodiment, the chemical cartridge 202 includes the chemical soaked in a fibrous matrix 206. The chemical can be any hygroscopic or non-hygroscopic in nature such as sodium bisulfate, poly aluminum chloride, aluminum sulfate, ferric chloride and ferric sulfate in the form of granules, powder or paste. Further, the chemical may be provided in the form of granules, powder, or paste. In one implementation, the fibrous matrix 206 may be a fiber composed of a fabric, mesh, foam, cotton, felt, nylon, polypropylene, polyamide, and polyester. In one implementation, diameter of the felt fiber used for the fibrous matrix 206 is in the range of about 5 micrometer (μηι) to 100 μπι. The chemical cartridge 202 holds the fibrous matrix 206 soaked in the chemical and allows a controlled release of the chemical through it. Further, the amount of the chemical soaked in the fibrous matrix 206 is determined based upon predefined conditions. The predefined conditions include, for example, the concentration of the chemical desired to be dosed in the water and amount of the water to be dosed with the chemical. In one implementation, the chemical cartridge 202 may be of any shape including, but not limited to, a circular, square, elliptical, and cylindrical shape.

[0030] Further, the dosing unit 116 is kept inside a casing 208 to make the chemical doser 104 leak proof. The casing 208 includes a dosing inlet 210 for receiving the water from a source of water and the .. dosing outlet 212 to provide the dosed water. The casing 208 further includes a breathing orifice 214 to maintain equal pressure between the dosing unit 116 and the fluid chamber 118 so that the device can also operate under variable pressure flow. In one implementation the breathing orifice 214 has a diameter in the range of about 1 millimeter (mm) to 3 mm.

[0031] The doser 204 is attached to the chemical cartridge 202 such that it receives one end of the fibrous matrix 206. The fibrous matrix 206 thus establishes a physical link between the doser 204 and the chemical cartridge 202 facilitating transfer of the chemical to the doser 204 for being dosed in the water. In one implementation, the doser 204 is in the shape of a circular cylinder and is provided with a slanting tip 216 having an elliptical cross section. The slant of the slanting tip 216 is made in such a way that the amount of the chemical dosed in the water varies in proportion to the flow rate of the water into the chemical doser 104. Varying the amount of the chemical in proportion to the flow rate of the water helps in ensuring that a controlled amount of the chemical is dosed, in the water. Further, height of the doser 204 and area of the slanting tip 216 in contact with the water may also be varied in order to vary the amount of the chemical released in the water. In one implementation, the height of the doser 204 varies from 2 centimeter (cm) to 4 cm. In another implementation, height of the slanting tip 216 varies in the range of about 0.5 cm to 2 cm. [0032] In one implementation, the fluid chamber 118 is provided such that it houses the doser 204. The fluid chamber 118 is configured to regulate the water level of the water flowing in through the fluid chamber 1 18 in order to control the area of the slanting tip 216 dipped in the water. For the purpose, the fluid chamber 1 18 includes regulating means such as orifices 218-1 , 218-2, and 218-3, hereinafter collectively referred to as regulating orifices 218. The regulating orifices 218 are provided to drain out water from the fluid chamber 1 18 into the mixing chamber 120 in order to maintain a desired rate of flow of the water in the fluid chamber 118. The regulating orifices 218 thus also work as water outlet for the fluid chamber 118. In one implementation, diameter of the orifices 218-1 is much smaller than the diameter of the dosing inlet 210. This difference in diameters results in accumulation and rise of level of water inside the fluid chamber 118. At larger flow rate the orifices 218-2 and 218-3 also start working as water outlets thus controlling the level of water inside the fluid chamber 1 18. The rise of water level in the fluid chamber 1 18 is controlled in such a way that the area of the slanting tip 216 dipped in the water is proportional to the flow rate of the water. Controlling flow rate of the water and the area of the slanting' tip 216 dipped in the water ensures proportional increase in amount of the chemical dosed in the water.

[0033] Thus, concentration of the chemical in the dosed water may be maintained in a predetermined range irrespective of the flow rate and water level of the water. The water along with the chemical drained by the regulating orifices 218 is received by the mixing chamber 120. The mixing chamber 120 mixes the chemical with the water so as to achieve uniform concentration of the chemical in the dosed water received from the dosing outlet 212 as shown by an arrow 220.

[0034] In operation, the water to be dosed is received by the chemical doser 104 via the dosing inlet 210 as shown by an arrow 222. The water subsequently enters into and gets collected in the fluid chamber 118. As the water starts collecting, the water level (not shown in the figure) increases inside the fluid chamber 118. On reaching a predetermined level, the water starts touching a bottom contact surface, i.e., the slanting tip 216 of the dosing unit 1 16, making the doser 204 release the chemical. With the increase of the water level, the outflow of the water through the orifice 218-1 also increases. Once the outflow through the orifice 218-1 matches with the inflow of the water through the dosing inlet 210, the water level attenuates to a predetermined value ensuring that a predetermined amount of the chemical is being mixed with the water. As the rate of inflow through the dosing inlet 210 increases, the water level further increases inside the fluid chamber 118 until it reaches the orifices 218-2 and 218-3. As the level of the water crosses the orifices 218-2 and 218-3, the orifices 218-2 and 218-3 also start acting as outlets and drain the water into the mixing chamber 120. This increases the rate of total outflow from the fluid chamber 1 18 and thus controls the increase of water level in a desired fashion.

[0035] In one implementation, the bottom most portion of the slanting tip 216 is placed just above the orifice 218-1. As the water flows into the fluid chamber 118, the water level increases and the slanting tip 216 starts touching rising water as soon as the water reaches the predetermined level. With the increase of the inflow of water, the water level increases and hence the area of the slanting tip 216 in contact with the water also increases. The water level is thus controlled in such a way that the contact area of the slanting tip 216 is proportional to the inflow rate of water into the fluid chamber 118.

[0036] Further, as stated previously, the doser 204 is also filled with the fibrous matrix

206 that generate numerous capillaries inside the doser 204. Water touching the slanting tip 216 rises up in the doser 204 due to the capillary action and touches the chemical cartridge 202 at a bottom surface. The water thus dissolves the chemical loaded within the chemical cartridge 202 and a concentration gradient of the chemical is set in the doser 204. The chemical present at the slanting tip 216 subsequently gets dissolved into the water. Further, as the water inflow into the fluid chamber 1 18 increases, the water level increases, and in turn touching area of the slanting tip 216 also increase and hence the amount of the chemical dosed into the water also increases. This maintains the chemical concentration into the dosed water. As the inflow of the water into the fluid chamber 118 stops, the water level starts decreasing. Consequently, the doser 204 stops dosing of the chemical as soon as the water level goes below the predetermined level. As the inflow of the water into the fluid chamber 1 18 resumes, the water level starts rising and comes in contact with the slanting tip 216, thus restarting the dosing of the chemical into the water, thus making the chemical dosing process consistent and automatic. The chemical doser 104 is thus configured to be synchronized with the flow of the liquid such that the chemical doser 104 starts and stops dosing of the chemical in accordance with the flow of the liquid. [0037] Figure 3 illustrates components of the chemical, doser 104 for automatic and metered dosing of a chemical into a liquid, according to a second embodiment of the present subject matter. In said embodiment, the chemical doser 104 includes the chemical in a crystal or a powder form. As previously discussed, the chemical doser 104 includes the dosing unit 1 16, the fluid chamber 118, and the mixing chamber 120. In said embodiment, the dosing unit 1 16 includes a container 302 to store the chemical and the doser 204 having the fibrous matrix 206. In one implementation, the doser 204 is attached to the container 302 in such a way that the chemical is always in a physical contact with the fibrous matrix 206 of the doser 204. The fluid chamber 1 18 and the mixing chamber 120 are similar to the embodiment described in the figure 2. The fluid chamber 118 thus includes the regulating means such as the regulating orifices 218 to regulate level of the liquid in the fluid chamber 118 such that at a predetermined level the liquid comes in contact with a bottom contact surface of the dosing unit 1 16 to receive the predetermined amount of the chemical. Although the Figure 3 has been described in considerable detail with respect to water, it will be understood that the chemical doser 104 can be used to dose a chemical in any liquid.

[0038] In operation, the water to be dosed is received by the chemical doser 104 via the dosing inlet 210 as shown by the arrow 222. The water subsequently enters into and gets collected in the fluid chamber 118. As the water starts collecting, the water level (not shown in the figure) increases inside the fluid chamber 1 18. On reaching a predetermined level, the water starts touching a bottom contact surface, i.e., the slanting tip 216 of the dosing unit 1 16, making the doser 204 release the chemical. With the increase , of the water level, the water starts rising inside the doser 204 via the capillary tubes formed in the fibrous matrix 206. With the rise of the water in the fibrous matrix 206, the portion of the fibrous matrix 206 touching the chemical gets wet. The chemical touching the wet fibrous matrix 206 subsequently starts dissolving in the vicinity of the fibrous matrix 206 and the container 302. The dissolved chemical gets diffused in the fibrous matrix 206 and reaches to the slanting tip 216. The chemical reaching the slanting tip in turn 216 gets released into the water touching the slanting tip 216 in the fluid chamber 118. The water along with the chemical enters the mixing chamber 120 that mixes the chemical with the water so as to achieve uniform concentration of the chemical in the dosed water received from the dosing outlet 212 as shown by the arrow 220. [0039] Further, as the inflow of the water varies, the water level in the fluid chamber 118 is controlled using the same mechanism as discussed in the first embodiment of the chemical doser 104 described in the figure 2. The dissolution of the chemical in the container 302 and releasing of the dissolved chemical into the water keeps on happening as long as the water remains in contact with the slanting tip 216. This makes chemical dosing process consistent and automatic enabling it to automatically start, stop, and adjust dosing of the chemical. The chemical doser 104 is thus configured to be synchronized with the flow of the liquid such that the chemical doser 104 starts and stops dosing of the chemical in accordance with the flow of the liquid. Further, providing the chemical in the form of crystals or powder makes the chemical doser 104 compact as the fibrous matrix 206 are now only provided in the doser 104.

[0040] Fig. 4 illustrates components of the chemical doser 104 for automatic and metered dosing of a chemical into a liquid, according to a third embodiment of the present subject matter. In said embodiment, the chemical doser 104 includes the chemical in a crystal or a powder form. As previously discussed, the chemical doser 104 includes the dosing unit 1 16, the fluid chamber 118, and the mixing chamber 120. In said embodiment, the dosing unit 116 includes the container 302 to store the chemical, the doser 204 having the fibrous matrix 206, a disc 402 in contact with the chemical for compressing the chemical towards the fibrous matrix 206. The disc 402 is supported by a spring 404 placed near the top surface of the container 302. In one implementation, the doser 204 is attached to the container 302 in such a way that the chemical is always in a physical contact with the fibrous matrix 206 of the doser 204.

[0041] Further, the disc 402 keeps the chemical compressed to ensure that a proper physical contact is maintained between the fibrous matrix 206 and the chemical. Further, as the chemical gets consumed, the spring 404 starts expanding, pushing the disc 402 and the chemical downwards. This gives an indication of unused amount of the chemical and thus acts as a life indicator of the chemical doser 104. Providing an indication of the unused amount of the chemical doser 104 helps in ensuring that the chemical doser 104 is not used beyond a safe prescribed limit The mechanism of the dissolution of the chemical and dosing of the chemical into the water is similar to the embodiment of the chemical doser 104 as described in the figure 3.. [0042] Figure 5 illustrates components of the chemical doser 104 for automatic and metered dosing of a chemical into a liquid such as water, according to a fourth embodiment of the present subject matter. As previously discussed, the chemical doser 104 includes the dosing unit 1 16, the fluid chamber 118, and the mixing chamber 120. In said embodiment, the dosing unit 1 16 includes a chemical releasing component 502 provided inside a doser 504. The doser 504 is provided with a perforated contact plate 506 at the bottom surface to release a predetermined amount of the chemical in the water. The perforated contact plate 506 helps water to reach to the bottom most chemical releasing component 502 to dissolve it from a bottom surface.

[0043] In one implementation, the chemical releasing component 502 is composed of the chemical intended to be dosed into the water, additives, binders and lubricants made in the form of a tablet by compressing at high pressure or in the form of a candle cast in a mould and dried at a suitable temperature to obtain a structural integrity. Examples of the additive include, but are not limited to, calcium hydroxide, calcium oxalate, calcium phosphate, D-galactose, magnesium carbonate, magnesium hydroxide, magnesium phosphate, magnesium oxalate or any combination thereof, and starch such as maize starch, potato starch etc.

[0044] In one embodiment, the chemical releasing component 502 is made in the form of a tablet composed of a chemical such as aluminum sulphate in the range of about 60% to 80% by weight, mixed with an additive such as maize starch in the range of about 20% to 40% by weight. A dry mixture thus obtained is compressed at pressure of about 1 ton to 5 tons for a time period of about 1 minute to 10 minutes in a suitable tablet press. The resulting tablet is ready to be used in the dosing unit 116.

[0045] In another embodiment, the chemical releasing component 502 is made in the form of a candle composed of a chemical such as aluminum sulphate in the range of about 60% to 80% by weight, mixed with an additive such as maize starch in the range of about 20% to 40% by weight. A suitable amount of water is added to a dry mixture thus obtained and molded in a die under a suitable pressure ranging from about 70 kilograms (kg) to 200 kg. The resulted candle is dried till the structural integrity is obtained. The resulting candle is ready to be used in the dosing unit 116. [0046] In one implementation, the fluid chamber 118 is provided such that it houses the doser 504. The fluid chamber 118 is configured to regulate the flow rate of the water flowing in through the fluid chamber 1 18 in order to control the chemical dipped in the water. For the purpose, the fluid chamber 118 includes regulating means such as a siphon tube 508. The siphon tube 508 controls the filling and emptying of the fluid chamber 118 thus regulating level of the water in the fluid chamber 1 18 such that at a predetermined level the water comes in contact with a bottom contact surface of the chemical composition 502, i.e., the face of the chemical composition 502 touching the perforated contact plate 506 of the dosing unit 116 to receive a predetermined amount of the chemical. The fluid chamber 1 18 further includes a dosing inlet 510 to receive water to be dosed with the chemical, a dosing outlet 512 to provide the dosed water, and a breather tube 514 to maintain equal pressure between the fluid chamber 1 18 and the mixing chamber 120 thus facilitating the operation of the dosing device 104 at variable pressure of the water flow.

[0047] In operation, the water to be dosed is received by chemical doser 104 via the dosing inlet 510 as shown by an arrow 516. The water subsequently enters into and gets collected in the fluid chamber 118. As the water starts collecting, the water level (not shown in the figure) increases inside the fluid chamber 118. Subsequently, the water starts entering into the siphon tube 508 via a siphon inlet 518. The water level keeps on rising within the fluid chamber 1 18 till it reaches up to the top of the siphon tube 508. In one implementation, the dosing unit 1 16 is placed inside the fluid chamber 118 such that the perforated contact plate 506 is little below the maximum height of the water level in the fluid chamber 118 and the siphon tube 508. Thus, on reaching a predetermined level, i.e., just below the top of the siphon tube 508, the water starts touching the perforated contact plate 506. As the water reaches up to the perforated contact plate 506 it enters into dosing unit 116 and touches the bottom most chemical releasing component 502 from its bottom surface, making the doser 204 release a predetermined amount of the chemical into the water.

[0048] Further, as the water level rises within the fluid chamber 1 18, the trapped air in the fluid chamber 1 18 is displaced to the mixing chamber 120 via the breather tube 514 making the pressure in the two chambers equal. As the water level reaches up to a top of the siphon tube 508, the siphon tube 508 starts draining the water from the fluid chamber 118 to the mixing chamber 120 through a siphon outlet 520 at a high flow rate. As the siphon tube 508 drains water from the fluid chamber 118, the water level comes down and when water level is below the predetermined level, it stops touching the perforated contact plate 506, thus stopping the further dissolution of the chemical releasing component 502. The water along with the chemical drained by the siphon tube 508 is received by the mixing chamber 120. The mixing chamber 120 mixes the chemical with the water so as to achieve uniform concentration of the chemical in the dosed water received from the dosing outlet 512 as shown by an arrow 522. Further, as the inflow of the water into the fluid chamber 1 18 stops, the water level starts decreasing. Consequently, the doser 504 stops dosing of the chemical as soon as the water level goes below the predetermined level. As the inflow of the water into the fluid chamber 1 18 resumes, the water level starts rising and comes in contact with the perforated contact plate 506, thus restarting the. dosing of the chemical into the water, thus making the chemical dosing process consistent and automatic. The chemical doser 104 is thus configured to be synchronized with the flow of the liquid such that the chemical doser 104 starts and stops dosing of the chemical in accordance with the flow of the liquid.

[0049] Although the Figure 5 has been described in considerable detail with respect to water, it will be understood that the chemical doser 104 can be used to dose a chemical in any liquid.

[0050] Figure 6 illustrates a graph depicting performance of a dosing device, such as the dosing device 104, in accordance with the first embodiment of the present subject matter. The graph 600 shows the results obtained after experiments were performed for testing performance of the dosing device 104 as a pH conditioner for conditioning pH of water. The pH conditioner was tested using 72 liters of untreated water having a pH level of about 8. The acidic salt used for dosing and the pH change was measured using known methods of measuring pH of water.

[0051] In the graph 600, a total amount of the untreated water, in liters, passed through the pH conditioner is taken as a reference position and is represented along a horizontal axis 602. Vertical axis 604 represents the pH value of the untreated water and the dosed water, while the flow rate of the untreated water through the pH conditioner is represented on a vertical axis 606. [0052] Curve 608 represents pH level of the untreated water provided to the pH conditioner. Curve 610 depicts pH level of the dosed water received after adjusting the pH level of the untreated water. Curve 612 depicts flow rate of untreated water through the pH conditioner. The graph 600 shows that the pH level in the dosed water is about 5.5 to 7.5 and is consistent across variable flow rates ranging from 2 liters per hour to 7 liters per hour.

[0053] Figure 7 illustrates a graph depicting performance of a dosing device, such as the dosing device 104, in accordance with the fourth embodiment of the present subject matter. The dosing device 104 is supplied with about 400 liters of water having negligible sulphate into it. An aluminum sulphate candle is used for dosing of aluminum sulphate into the water and dosing is measured by measuring sulphate concentration in the output water using known methods of sulphate measurement.

[0054] In the graph 700, a total amourit of water, in liters, passed through the dosing device 104 is taken as a reference position and is represented along a horizontal axis 702. Vertical axis 704 represents sulphate ion concentration in the water. Curve 706 represents sulphate ion concentration in the chemical dosed water.

[0055] As seen in Figure 7, the sulphate ion concentration in the chemical dosed water is in the range of about 300 to 350 parts per million (ppm) across the predicted life of the chemical candle except at the start and end of the dosing process. Further, the dissolution of the sulphate ions stabilizes at the beginning of the dosing process, i.e., when the chemical candle is new, and tapers off at end of dosing process, i.e., when the chemical candle is dissolved.

[0056] Although implementations of a dosing device have been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as implementations of the dosing device.

Claims

I/We claim:

1. A device (104) for dosing a chemical in a liquid, the device comprising:

a fluid chamber (1 18) to receive the liquid, wherein the fluid chamber (1 18) comprises a regulating means configured to regulate a level of the liquid in the fluid chamber (1 18); and

a dosing unit (1 16) having the chemical, wherein the dosing unit (116) is coupled to the fluid chamber (118) to release a predetermined amount of the chemical in the liquid flowing through the fluid chamber (1 18) when the liquid reaches a predetermined level, and wherein the liquid comes in contact with a bottom contact surface of the dosing unit (116) at the predetermined level.

2. The device (104) as claimed in claims 1, wherein the predetermined amount of the chemical dosed in the liquid is based in part on flow rate of the liquid entering the fluid chamber (1 18).

3. The device (104) as claimed in claim 1, wherein the dosing unit (1 16) comprises:

a chemical cartridge (202) comprising a fibrous matrix (206) soaked in the chemical; and

a doser (204) attached to the chemical cartridge (202), wherein the doser (204) is provided with the bottom contact surface having a slanting tip (216) to release the predetermined amount of the chemical.

4. The device (104) as claimed in claim 1, wherein the dosing unit (1 16) comprises:

a container (302) to store the chemical; and

a doser (204) attached to the container (302), wherein the doser (204) comprises: a fibrous matrix (206) for providing the chemical; and

the bottom contact surface having a slanting tip (216) to release the predetermined amount of the chemical, through the fibrous matrix (206), in the liquid.

5. The device (104) as claimed in claim 4, wherein the dosing unit (116) further comprises:

a disc (402) to compress the chemical to maintain a physical contact between the chemical and the fibrous matrix (206); and

a spring (404) to support the disk (402)..

6. The device (104) as claimed in any of the claims 3 to 5, wherein the predetermined amount of the chemical dosed in the liquid is based at least in part on area of the slanting tip (216) in contact with the liquid entering the fluid chamber (118).

7. The device (104) as claimed in any of the claims 3 to 6, wherein height of the slanting tip (216) is in a range of about 0.5 centimeters (cm) to 2 cm.

8. The device (104) as claimed in any of the claims 3 to 7, wherein the predetermined amount of the chemical dosed in the liquid is based at least in part on height of the doser (204).

9. The device (104) as claimed in any of the claims 3 to 8, wherein height of the doser (204) is in the range of about 2 cm to 4 cm.

10. The device (104) as claimed in any of the claims 3 to 9, wherein the fibrous matrix (206) comprises a fiber selected from a group consisting of a fabric, mesh, foam, cotton, felt, nylon, polypropylene, polyamide, and polyester.

1 1. The device (104) as claimed in claim 10, wherein a diameter of the fiber is in the range of about 5 micrometer (μιη) to 100 μπι.

12. The device (104) as claimed in claim 1, wherein the regulating means comprises regulating orifices (218) to transfer the liquid along with the chemical, dosed by the dosing unit (1 16), from the fluid chamber (1 18) into a mixing chamber (120) to regulate the level of the liquid in the fluid chamber (118).

13. The device (104) as claimed in claim 1, further comprising a breathing orifice (214) to maintain equal pressure between the dosing unit (116) and the fluid chamber (1 18).

14. The device (104) as claimed in claim 1, wherein the dosing unit (116) comprises a doser (504) to release the predetermined amount of the chemical in the liquid, and wherein the doser (504) comprises,

at least one chemical releasing component (502) having the chemical; and a perforated contact plate (506) provided at the bottom contact surface to allow, at the predetermined level, the liquid to enter the doser (504) such that the liquid comes in contact with the at least one chemical releasing component (502) to dissolve the predetermined amount of the chemical.

15. The device (104) as claimed in claim 14, wherein the at least one chemical releasing component (502) comprises an additive selected from a group consisting of calcium hydroxide, calcium oxalate, calcium phosphate, D-galactose, magnesium carbonate, magnesium hydroxide, magnesium phosphate, magnesium oxalate, starch, arid combinations thereof.

16. The device (104) as claimed in claim 14, wherein the at least one chemical releasing ( component (502) comprises at least one of binders and lubricants.

17. The device (104) as claimed in claim 14, wherein the at least one chemical releasing component (502) is formed as one of a tablet and a candle.

18. The device (104) as claimed in claim 14, wherein the at least one chemical releasing component (502) comprises:

aluminum sulphate in the range of about 60% to 80% by weight; and

starch in the range of about 20% to 40% by weight.

19. The device (104) as claimed in claim 1, wherein the regulating means comprises a siphon tube (508) to transfer the liquid along with the chemical, dosed by the dosing unit (116), from the fluid chamber (1 18) into a mixing chamber (120).

20. The device (104) as claimed in claim 19, further comprising a breather tube (514) to maintain equal pressure between the fluid chamber (118) and the mixing chamber (120).

21. The device (1,04) as claimed in claim 1, further comprising a mixing chamber (120) coupled to the fluid chamber (1 18), wherein the mixing chamber (120) is configured to:

receive, from the fluid chamber (118), the liquid along with the chemical dosed by the dosing unit (1 16); and

uniformly mix the chemical and the liquid to provide a dosed liquid having a substantially uniform concentration of the chemical.

22. The device (104) as claimed in claim 1, wherein the chemical comprises a chemical composition selected from a group consisting of a detergent composition, a water softener, and a pH conditioner.

23. The device (104) as claimed in claim 1, wherein the chemical is at least one of a hygroscopic chemical, a non-hygroscopic chemical, a crystalline chemical, and an amorphous chemical.

24. The device (104) as claimed in claim 1, wherein the device (104) is configured to be synchronized with the flow of the liquid such that the device (104) starts and stops dosing of the chemical in accordance with the flow of the liquid.

25. The device (104) as claimed in claim 1, wherein the device (104) is configured to dose the chemical at variable pressures of the flow of the liquid without altering the pressure of the flow of the liquid.