Device for purifying a liquid

The claimed invention relates to a filtering device for purifying a liquid, intended for softening and purifying tap water and other liquids for domestic use. A device for purifying a liquid, having an inlet channel and an outlet channel, consists of at least two tanks, one for a softening agent and one for a regenerating solution, and a control mechanism including a housing, which consists of at least three parts which form chambers and liquid-conducting cavities, at least two pistons, which are located in the chambers and which are linked by means of a cam mechanism to an engine, a saline valve, and a discharge valve; the control mechanism is designed such that the pistons can move simultaneously in the chambers in opposite directions, at the same time alternately shutting off the liquid-conducting cavities in the housing; at least two liquid-conducting cavities are formed between the indicated portions of the housing, and at least one cavity is formed between the closest portion of the housing to the upper portion of the tank for the softening agent and the upper portion of the tank for the softening agent. The technical result consists in increasing the reliability and simplifying the design of a device for purifying a liquid, and in decreasing the weight of the device for purifying a liquid.

TECHNICAL FIELD

The invention relates to a filtering device for fluid treatment intended for softening and cleaning of tap water and other fluids utilized for domestic purposes.

BACKGROUND

Currently, one of the most effective methods to combat increased water hardness is the use of automatic filtering softeners. Such devices, as a result of the liquid processing, provide a replacement of“hard” salts with “soft” salts. Thus, there is a change in the chemical composition of the liquid to be treated, i.e., the calcium and magnesium ions are replaced with sodium ions, with which the ion-exchange resin is enriched. The treated liquid is fed through an inlet duct into a container device filled with a softening agent. After that, softened liquid is fed to the consumer via an output device channel. Over time, the absorption properties of the resin are reduced, and, therefore, it is necessary to regenerate the ion-exchange resin. The recovery process of ion-exchange properties of the resin is carried out by supplying a saline solution into a container with a softening agent, resulting in the inverse substitution of the accumulated calcium and magnesium ions with sodium ions. Then, the ion exchange resin is backwashed, and the eluted contaminants are dumped into drainage.

Fluid treatment devices used for softening a liquid and formed with different design features are known in the prior art and generally operate according to the same algorithm. These devices are primarily characterized by cumbersome and complex technical execution. As used herein, the prior art shows the closest analogs to the technical essence, namely, mechanisms constructed using valve-piston systems for the distribution of liquid in the device for cleaning liquid.

Known design of the device for water purification, according to the U.S. Pat. No. 5,116,491 (IPC B01J 49/00, C02F 1/42, B01D 21/30; . . . 26, May 1992 publ), consists of a control mechanism with two pistons on one shaft and two tanks in one case, where a first tank is filled with the softening agent, and the second tank is filled with a solution promoting regeneration of the softening agent. For purposes of a given algorithm of the device, and to provide liquid interface between the nodes, the device utilizes a valve-piston fluid flow distribution system having a horizontally positioned shaft with two pistons and a master controller. Raw liquid is fed under pressure into the inlet of the housing of the valve-piston system and enters into the chamber, in which the shaft with its rigidly affixed two valves is positioned. The shaft is connected to a drive mechanism for horizontal reciprocating movement of said shaft within said chamber allowing for regulation of the liquid flow within the device for water purification. Chamber, in which the piston shaft is located, has slotted holes, where each hole is an inlet/outlet aperture for raw water, purified water, for drain water discharge and a hole for fluid communication with the tank filled with the solution promoting regeneration of the softening agent. This arrangement of pistons in the chamber allows the passage of fluid through the container filled with the softening agent and the yield softened fluid consumer. After a certain time, the control module includes a motor that moves the rod and piston, and the location of the piston is changed, and they cover the feed stream of liquid into a container with a softening agent in the opposite direction, and the first backwash stage begins, accompanied by a discharge of water into the drain. In the second stage backwashing the simultaneous movement of the rod and including an injector, thereby supplying the regenerate saline solution container of softening agent. After time regeneration is disabled by moving the injector rod and the wash softening process is performed by regenerating the reagent solution, followed by displacement of the rod and the switching of the initial fluid flow into the container filled with softening agent. The input and output channels in the apparatus provide the initial fluid flow into the cavity, where the piston rod with pistons, so this system does not eliminate the pressure drop which reduces the performance of the device. Solving this substantial lack possible by increasing the center distance between the input and output channels, but this will increase the piston stroke and, as a consequence, increase the size of the device.

In the prior-known patent design technology U.S. Pat. No. 6,176,258 (IPC F16K 31/52, F16K 31/524, F16K 11/06, publ. 23 Jan. 2001g). This invention relates to the control device a fluid treatment system which includes two vessel control mechanism with two pistons and drive rotational motion into a reciprocating movement, where the switching of fluid flow using the valve-piston system for distributing fluid streams with a horizontal arrangement of main and additional stocks. When this movement of the piston by means of follower connected to the cam member interconnected with the drive mechanism (motor). As rotation of the cam member a cam follower moves along the path deposited on a side of the cam surface and the piston, respectively, moves in a longitudinal horizontal direction along the axis to the extreme left and right positions (reciprocating) connecting the liquid flow depending on the predetermined algorithm system operation. As soon as rotary cam element continues to rotate, the cam follower passes through track and at this time, respectively, the piston advances to the left and right on the horizontal axis and connecting disconnecting fluid flows. further movement of the piston in accordance with a predefined algorithm, and can perform various functions, such as controlling the regeneration step of softening agent. by U.S. Pat. No. 6,176,258, the main drawback of the design are the external dimensions, where the horizontal position of the piston (rod) is extremely inconvenient for the user since significantly increases the size of the product.

The prior art known to the controlling mechanism of the device for cleaning liquid with two tanks on the U.S. Pat. No. 5,628,899 (C02F 1/42, B01D 24/46, publ. 13 May 1997 city). This device includes two containers filled softening agent, and a container of saline solution (FIG. Not shown), where the relationship of said containers through a controlling mechanism. The controlling mechanism has a housing with inlet and outlet conduits for the treated liquid tank switching valve comprising a rotor, wherein the rotor provides fluid communication between said containers in accordance with a predetermined algorithm device. The rotor has an upper end and a lower end, and the upper and lower chambers separated by a partition. The upper chamber of the rotor has a number of inlet openings in the upper end of the rotor where inlet holes provide fluid communication between the outlet and the upper chamber when the rotor is in the first and second positions. Furthermore, the upper chamber has an outlet which provides fluid communication between the upper chamber and the rotor inlet tank with softening agent. When the rotor turns, this outlet is closed. The lower chamber of the rotor has a number of outlet openings in the upper end of the lower chamber of the rotor. Between the inlet and outlet openings rotor has pads arranged on the rotor circumference, which excludes fluid flow between the inlet and outlet openings on the outside of the rotor, between the rotor and the frame or housing of the valve switching tanks. It is connected to the rotor shaft through the cam member, which selectively rotates about an axis that provides selective rotation of the shaft and rotor about an axis between first and second positions according to a predetermined algorithm device. When the piston has an aperture disposed in the longitudinal direction so that when the piston moves in the longitudinal direction is provided by selectively opening and closing the liquid channel. According to the measurements of the flowmeter, the rotary cam member is installed in the position in accordance with a predetermined algorithm of the system when the cam follower and the piston moving to another position. The motor rotates the cam member and thereby of the rotor shaft in order to provide selective rotation of the rotor from the first position to the second. The advantage of such fluid treatment systems is that the consumer, due to the fact that the system comprises two containers with a softening agent, purified water is always received. Lack of fluid purification system according to the U.S. Pat. No. 5,628,899 is as follows. For the distribution of liquid in the device is used for a joint movement of the piston rod in the longitudinal direction and the rotation of the rotor with the holes, which increases the size and weight of the device for cleaning liquid.

In the prior art device is known by the U.S. Pat. No. 3,797,523 (IPC V01D 29/38, publ. Mar. 19, 1974), which describes the water softener valve assembly design, which uses the valve-piston system for the distribution of liquid within the water softener, the valve assembly has a main body consisting of the lower and upper portions sealingly coupled with standard fasteners. The upper part of the housing is provided with two chambers and a piston disposed therein, wherein each chamber has upper end and a lower end and connected by a channel with a tank for softening agent. The input channel for the source liquid is connected directly to one of said chambers. The maximum lower position of both pistons ensures the flow of incoming feed liquid through the vessel for regenerating the reagent, in accordance with a predetermined algorithm device. In the regeneration step, and the initial backwash liquid flowing in the inlet channel, it is sent directly to the outlet, thereby preventing interruption of water flow to the user performing the regeneration or backwash. Similar features of the claimed device for cleaning fluid and said analog design is the presence in the two control pistons which, in accordance with a predetermined algorithm the respective open and close liquid flows in the device. Moving is done by means of hydraulic piston valve, for example, by means of electromagnetic valves, and springs. In the description, the author refers to the application U.S. application Ser. No. 256,172 (U.S. Pat. No. 3,792,614), and points out that the present system can be equipped with an automatic controller, represented by the analogue contains a number of shortcomings. The disadvantage of this analog is the presence of six hydraulic valves involved in the distribution of fluid within the device. Failure of the valve can result in malfunction of the entire valve assembly of the water softener, and to allocate, for example, saline consumer. Construction pistons comprising as means ensuring movement of said pistons—the spring is not sufficiently reliable. Furthermore, the presence of the springs in the structure of U.S. Pat. No. 3,797,523 may result in the reciprocating motion of the pistons to the accumulation of insoluble impurities on the sealing elements during operation. This significant shortcoming will be eliminated after the structure shown in U.S. Pat. No. 8,302,631, wherein for eliminating the above drawback side walls made of a soft abrasive material.

The prior art discloses a device for cleaning liquid to a node on the control valve U.S. Pat. No. 8,302,631 (IPC F16K 31/48, C02F 1/00, C02F 1/42, F17D 3/00, C02F 5/00, publ. 6 Nov. 2012) selected as the prototype of the claimed invention. Cleaner fluid includes input and output channels, the tank for softening agent and the tank for regeneration solution, housing with conductive fluid channels and six compartments (chambers) designed to contain the cartridges to ensure the efficient movement of them six pistons, drive provided with a number of individual radial cams, driven by a motor, wherein each of said cams able to drive each respective piston and said end cam has an outer edge which has at least one projection and recess for engagement with respective piston. Thus each cam are interconnected through a reduction gear driven by the motor, wherein the pistons are moved by means of a spring and the water pressure, and fluid channels shut-off is performed due to the shape of the radial-piston cam in accordance with a predetermined algorithm. Those. the location of each piston defined in the system configuration of the cam, namely, end peripheral edge configuration of the cam designed to engage with one of said pistons. A significant drawback of the known technical solutions is a complication of the construction by introducing a reducer and a series of cams connected to the individual pistons, which separate the piston performs an appropriate algorithm one operation. Furthermore, the use of radial movement of the cam provides a piston in one direction only, which is used for reverse kinematical additional elements, such as springs, creating additional load on the body of the control mechanism.

DISCLOSURE OF INVENTION

The problem to be solved by the claimed technical solution is the creation of a new control mechanism for purifying liquid and reducing operational costs.

The technical result that can be obtained by carrying out the claimed invention is an increase in reliability and simplification of the design for a liquid treatment device, and weight reduction for devices for purifying liquid.

The claimed technical result is achieved due to the fact that a device for cleaning liquid, having an inlet and an outlet, consists of at least two tanks, i.e., one for the softening agent and one for the regenerating solution, the control mechanism comprising a housing, consisting of at least three parts forming chambers and fluid conducting cavities, at least two pistons disposed in the chambers and interconnected via a cam mechanism with a motor, a saline valve, and a discharge valve, wherein the control mechanism is configured to facilitate a simultaneous movement of the pistons in the chambers in opposite directions and simultaneous variable shut-off of liquid conducting cavities in the housing, wherein at least two liquid conducting cavities are formed between said housing parts, and at least one liquid conducting cavity is formed between the part of the housing closest to the top of the tank for softening agent and the uppermost part of the tank for softening agent, wherein the cam mechanism is in the form a cylindrical cam having an outer profile to provide a two-way movement of these two pistons, wherein two rollers are connected with the shafts of said pistons on which the rollers are installed on the outer profile at an equal distance from each other, each part of the housing has projections and depressions forming said cavity, wherein, in the axial plane, the cavities are combined into the chambers, wherein the parts of the housing are configured to sealingly interconnect at the protrusions, wherein the housing parts are adapted to be inserted into each other, wherein the projections are arranged on the perimeter said housing parts, where the upper part of the housing with the inlet and outlet channels is sealingly connected to the top of the tank for the softening agent so as to position at least two housing parts therebetween, wherein one of said two pistons is connected to a saline valve via the lever mechanism, and the other piston is formed integrally with the discharge valve, wherein the lever mechanism comprises a pusher fixedly mounted on the shaft of the piston, and a lever fixedly mounted on the saline valve, wherein the lever has a shaped groove for the entry therein of said pusher, thus shaped groove being located along the piston stroke and, when the pusher is in said recess or does not contact with the lever, the saline valve is closed, where the pistons and valves are interconnected via a cam mechanism, wherein the apparatus comprises at least two tanks for softening agent and one tank for the regenerating solution, connected interconnected via working lines through a corresponding control mechanism, wherein each tank for softening agent is provided with a control mechanism which are provided with a single controller, wherein each control mechanism is provided with an individual controller, where the apparatus is provided with one drain channel, wherein each tank for softening agent is provided with its own drain channel, wherein the wall of the tank for softening agent includes zones characterized by increased resistance to deformation, where the zones are formed by radial and vertical elements made integrally with the tank wall, wherein at least one side opening for loading softening agent is disposed between the radial elements, wherein an opening for loading softening agent is made at the bottom of the tank for softening agent, wherein the radial elements are spaced preferably not less than 1/7 and not more than ⅓ of the diameter of the tank, preferably ⅕ of the diameter of the tank, wherein at least one lateral opening is preferably reinforced with a vertical element, wherein the radial and vertical elements are disposed relatively in between the input and output means for containment of the softening agent, and the radial and vertical elements are arranged relatively in between the input and output means for containment of the softening agent, wherein said means are advantageously in the form of a corrugated grid and disposed on the inner surface of the wall of the tank for softening agent.

A distinctive feature of the claimed invention is the design of the control mechanism, the relative positions and the interaction of its components. The invention simplifies the design of the control mechanism and thereby improves the reliability and reduces the weight of the device for purifying liquid.

DESCRIPTION OF THE INVENTION

The inventive apparatus1for purifying fluid having the inlet channel2and the outlet channel3comprises at least tank4for a softening agent and tank5for a regenerating solution, the control mechanism6(FIG. 1), the mechanism comprising a housing, having at least three parts7,8,9(FIG. 3) forming chambers10,11(FIG. 4) and liquid-conducting cavities12,13,14,15(FIGS. 3-6), at least two pistons16,17(FIG. 4) arranged in the chambers10,11(FIG. 4) and saline valve20(FIGS. 2,5) and discharge valve21(FIG. 6) interconnected through a cam mechanism18(FIG. 5) with a motor19(FIG. 2). The apparatus1may be connected to the pipeline under pressure, such as a drinking-water supply system, therefore the inlet channel2can be formed as a nozzle (not shown) with a shut-off hydraulic valve, for example, mechanical22(FIG. 1). To the outlet channel3can be connected, for example, a water supply pipe of residential buildings. Tank4for the softening agent and tank5for the regenerating solution are interconnected via the control mechanism6, for example, via a flexible connecting tube23(FIG. 1). The housing of the control mechanism6may be formed, for example, integrally with the upper portion of the tank4for the softening agent (FIG. 6) or as a separate body connected with the upper part of the tank4for softening agent, for example, via a threaded connection (not shown). The control mechanism6is intended for distribution of the incoming fluid to be cleaned, and of the liquid located inside the apparatus1in sequence according to a predetermined algorithm of the apparatus1. The housing of the control mechanism6(FIG. 2) includes at least three parts7,8,9(FIGS. 3-6) sealingly interconnected to each other using the sealing elements24(FIG. 3), which sealing elements24are, preferably, circular O-rings. In the inventive construction, part7of the housing with an inlet channel2and an outlet channel3(FIG. 7) is sealingly connected to an upper portion of the tank4for softening agent via, for example, a clamp25(FIG. 1), while the other two parts8and9of the housing are located therebetween, with each housing part being adapted to be insertable into another (FIGS. 3-6). Parts7,8,9(FIG. 7) of the housing can be made, for example, using an injection-molding machine utilized to manufacture parts from thermoplastic materials by injection molding, that enables the use of the parts without any additional machining. The starting material for the manufacture of parts8,9of the housing is, for example, polyoxymethylene. Parts7,8,9(FIG. 7) of the housing can be made, for example, in a circular shape or any other shape (not shown). Each part7,8,9(FIG. 7) of the housing has projections26and depressions27forming the liquid-conducting cavities12,13,14,15, wherein in the axial plane said cavities are combined by chambers10,11. Projections26are located at the perimeter of parts7,8,9of the housing, wherein the upper part7of the housing with inlet channel2and outlet channel3is sealingly connected to the top of the tank4for the softening agent such that at least two parts8,9of the housing can be positioned therebetween. Cavities12,13,14,15(FIG. 3) intersect with at least two chambers10,11(FIG. 4) such that said cavities12,13,14,15(FIGS. 3-6) in the inventive design function as fluid-conductive channels, shut-off or connection of which is achieved using at least two pistons16,17located in chambers10,11(FIG. 4). These pistons16,17have slots in which sealing elements28are installed (FIG. 4) to enable hermetical sealing between the respective cavities12,13,14,15(FIG. 3). Algorithm of the apparatus1is installed in the controller (not shown) and is carried out due to a unitary structure of the housing of the control mechanism6(FIG. 1) and the reciprocating movement of the pistons16,17in chambers10,11(FIG. 4). Each piston16,17has a shaft which is fixed to a cam mechanism18via a pusher (FIG. 4), where the cam mechanism is connected, for example, via a gear, to the motor19(FIG. 2). During operation of the apparatus1, movement of the pistons16,17is achieved by the design of the rotary cam mechanism18driven by motor19(FIG. 2). The cam mechanism18is formed as a cylindrical cam29with the outer profile30to provide a two-way movement of the two pistons16,17(FIG. 5). The outer profile30includes at least two rollers31set equidistant from each other (FIG. 3) and connected with said pistons16,17on the shafts. Course of the cam can be determined by those skilled in the art, depending on the dimensions of the device for purifying the fluid and its performance. The claimed apparatus1for purifying fluid provides a stage of backwash and regeneration of the softening agent. Backwash of the softening agent provides cleaning of the most contaminated lower layers, where the pollution settles, followed by discharge of flushing liquid through the discharge valve21into the drainage channel32(FIG. 6). For the best removal of such contaminants from the fluid being cleaned, generally, the tank for softening agent is provided with the input and output means of containment of the softening agent, which also perform pre-filter and post-filter function, respectively. These means are usually disposed on and fixed to the inner surface of the tank's wall. In the claimed invention, in order to increase the filtering capacity of the area, preferably such means are corrugated or formed as a corrugated grid (not shown). Regeneration of the softening agent is carried out by passing a saline solution through a layer of the softening agent. The saline solution is prepared and stored in a tank5for the regenerating solution, wherein the tank5is equipped with a feed opening (not shown) provided for the replenishment of the tank5(FIG. 1) with the regenerating agent, such as table salt. Outsource of the saline solution for regeneration of the softening agent from the tank5(FIG. 1) is performed by means of an ejector33(FIGS. 2, 6) located outside the housing of the control mechanism6(FIG. 1) and interconnected with the saline valve20(FIG. 2, 6) and saline node34(FIG. 1). Saline node34is configured as a housing with a tube35conducting saline solution and a filter36, such as a mesh for trapping undissolved salt granules (FIG. 1). Saline node34may be provided, for example, with a saline flow sensor or a salinity sensor (not shown) informing the consumer of the need to refill the tank5for the regenerating solution. Saline valve20(FIG. 5) is connected via a lever mechanism to the shaft of the nearest piston (in this case, the shaft of the piston17). The lever mechanism comprises a pusher37, which is fixedly mounted on the shaft of the piston rod17, and a lever38fixedly mounted on the saline valve20, where lever38has a shaped groove for the entry therein of said pusher37, and wherein the shaped groove is located along the course of piston17, and, when pusher37is positioned in said shaped groove of the lever38(FIG. 5) or when it is not in contact with the lever38(for example, at the maximum upper position of the piston17,FIG. 3), then saline valve20is closed. The inventive apparatus1is provided with a discharge valve21(FIG. 6) and a drain channel32(FIGS. 6, 9). Discharge valve21is actuated and operates synchronously with the nearest piston shaft (in this case with the shaft of piston16), as shown inFIGS. 3-6. Pistons16,17have the same purpose, namely enclosing some cavities and connecting other cavities to create predetermined flows of liquid, but they have differences in design concept. The shaft of piston17is connected to saline valve20(FIG. 5) via the leaver mechanism, wherein the saline valve20is turned on and off in accordance with a predetermined algorithm of the apparatus1. The opposing piston16is formed integrally with a discharge valve21designed to open and close the drain channel32(FIG. 6), where the discharge valve21is opened and closed in accordance with a predetermined algorithm of the apparatus1(FIG. 1). For better understanding of the distribution algorithm for the fluid located within the apparatus1for fluid treatment, control mechanism6is presented by a longitudinal section A-A, cross section B-B, as well as cross-section C-C (FIGS. 3-6). Device for purifying the liquid may be executed in various modifications, and may include additional tanks with softening agent or, for example, tanks filled with sorption material, and/or ultra-violet sources. Within the claimed invention, the apparatus1for purifying liquid comprises at least two, for example, four, tanks4for the softening agent and one tank5for the regeneration solution (FIG. 8), the tanks being connected therebetween, for example, in series or in parallel using at least three working lines via a corresponding control mechanism6, wherein each tank5for the softening agent includes an operating mechanism6(FIG. 8). This construction of the purifying apparatus allows to receive softened water at all stages of fluid purifying process. Additionally, such an apparatus1(FIG. 8) may be provided with a single controller (not shown) or each control mechanism6may be provided with its own individual controller (not shown), where apparatus1is provided with a single drain channel (FIG. 8) or each tank4for the softening agent is provided with its own drain channel32(FIG. 9). In the disclosed apparatus1, tank4for the softening agent is used for purifying the liquid, where the wall of the tank4is formed with areas39(FIG. 9), characterized by an increased resistance to deformation, wherein areas39are formed by radial40and vertical elements41made in one piece with the wall of the tank4for the softening agent (FIG. 1), and wherein at least one lateral opening42(FIG. 9) is located between the radial elements40. This opening42is used for loading the softening agent into the tank4. Radial elements40and vertical elements41(FIG. 9), in this case, are preferably spaced by not less than 1/7 and not more than ⅓ of the diameter of the tank4, most preferably by ⅕ of the diameter of the tank4. The purpose of manufacturing tank4with the radial elements40and vertical elements41is to increase the reliability of strength of the at least one side opening42, located between the radial elements40, wherein the at least one lateral opening42is preferably reinforced with the vertical element41. In order to ensure minimum deformation of the tank4for the softening agent, radial elements40and vertical elements41are arranged between the output43and input44means of containment of the softening, said means being arranged on the inner surface of the wall of the tank4for the softening agent (FIG. 9). The opening42for loading the softening agent into the tank4can be disposed at the bottom portion of the tank4for the softening agent.

Apparatus for purifying the fluid performs as follows. Liquid to be purified, enters from the inlet channel2into the apparatus1(FIG. 1) for purifying the fluid and flows into the housing of the control mechanism6(FIG. 3). The inlet channel2, in this case, can be connected, for example, to the water supply system or another source of raw liquid under pressure. Within the housing of the control mechanism6, the flow of raw liquid fills the inner space of the cavity12conducting the fluid and further spreads along the open chamber10(FIG. 3), where piston16(FIG. 3) is located in the lowest most position, and into the tank4(FIG. 1) for the softening agent, which is, for example, an ion exchange resin. Such position of the piston16allows the passage of the raw liquid into the tank4filled with the softening agent. The design of the tank4with the softening agent includes a housing with a pipe45, located in a central portion of the housing (FIG. 1) for output of fluid which passed through the softening agent layer in the interior of the tank4. Pipe45for the output of treated liquid from tank4with the softening agent is always in fluid communication with the cavity14conducting fluid that provides fluid communication with the outlet channel3of the apparatus1for purifying the fluid. Piston17is positioned at the topmost position that allows the treated liquid to output from the cavity15conducting the fluid along chamber11(FIG. 4) into the outlet channel3of the apparatus1. Thus, the arrangement of the pistons16,17in the filtering mode (first position of the control mechanism.FIG. 3) enables the supply of the raw liquid into the tank4with the softening agent and the subsequent delivery of the treated liquid to the consumer. In the disclosed apparatus1for purifying liquid, automatic switching of the modes is performed by a controller (not shown), for example, in accordance with the flow rate of treated liquid, or the time or the total amount of soluble solids in the treated liquid. Repositioning of the pistons16,17is carried out via their interconnection through the cam mechanism18with the motor19. The cam mechanism18is rotated to provide movement of the pistons16,17, and a control mechanism6takes an intermediate position with a brief opening of the saline valve20(the second position of the control mechanism,FIG. 4). In this position, pistons16,17do not change the direction of the main flow of the source liquid described above. Because the saline valve20is connected to the shaft of the piston17via a lever mechanism, there is a brief opening of the saline valve20, which in turn allows for the connection tube23and the tube35conducting the saline solution to be filled with purified water. Such an option is required to remove the stagnant air (air pockets) which may be formed in these tubes since the last opening of the saline valve20, in the saline solution supply mode into the tank4with the softening agent at the regeneration of the softening agent stage, and is a preparatory operation prior to regeneration of the softening agent. This option is performed during rotation of the cam gear18and is an intermediate position, when piston17continues to descend in chamber11and piston16continues to rise in chamber10. The subsequent stop of the cam mechanism18and, accordingly, of the two pistons16,17, leads to closing of the saline valve20connected to the piston17(FIG. 5) and a separation of the fluid conducting cavities12and13(FIG. 5) with piston16(FIG. 4). The control mechanism6takes the backwash position (third position of the control mechanism,FIG. 5). Raw fluid continues to flow through the inlet channel2of the apparatus1into the housing of the control mechanism6through the cavity12(FIG. 5) and, because the cavity13(FIG. 3) is closed and the piston17(FIG. 5) has moved downwards and created a fluid communication between cavity12and cavity15, the liquid reverses its direction. This arrangement of pistons16,17provides a flow of source fluid through the cavity12into the cavity15and further along the chamber11, in which piston17is positioned, and into the cavity14, which is always in a fluid relationship with the pipe45. The raw liquid passes along the entire length of pipe45and flows through a layer of the softening agent into the cavity13. The piston16is formed integrally with the discharge valve21(FIG. 6), the upward movement of which along the chamber10enables a fluid communication with the drain channel32. Such positioning of the control mechanism6provides a backwash of the contents of tank4. During backwashing, outlet channel3of the apparatus1is open, and the consumer receives initial raw liquid, as the piston arrangement16,17provides a fluid communication between the inlet2and the outlet3of the apparatus1through the cavities12and15. After the backwash time expires, in accordance with a predetermined algorithm of the apparatus1, the controller sends a signal to the motor19, which carries rotation of the cam mechanism18. The piston17is moved to the lowest most position and the piston16is moved to the topmost position. The control mechanism6(FIG. 1) takes the position of the regeneration of the softening agent (the fourth position of the control mechanism,FIG. 6). In this position, the piston17via the lever mechanism opens the saline valve20, and separates the cavity14from the cavity15so that the raw liquid is fed into the tank4with softening agent through the ejector33, located outside the housing of the control mechanism6, and by the ejection effect saline solution from the tank5is fed into the cavity14interconnected with the tube45of the tank4with the softening agent, saline valve20is normally open. Piston16is located in the topmost position and divides cavities12and13, wherein the fluid connection is created between the cavity13and the drain channel32, the discharge valve21is normally open. The softening agent regeneration step continues until the entire saline solution in the tank5is utilized. During regeneration, outlet channel3of the apparatus1is open, and the consumer receives the original raw liquid, as the piston arrangement16,17provides fluid communication between the inlet2and the outlet3of the apparatus1through cavities12and15. Regeneration of the softening agent ends with a backwash, wherein the wash water is passed in the opposite direction in order to agitate the softening agent. Backwashing is done at a predetermined time and depends on the volume of the tank4with the softening agent, and is performed at a slower rate than the backwashing performed before the regeneration step. At the end of the regeneration, the controller (not shown) sends a signal to the motor19, which drives the cam mechanism, and pistons16,17perform a corresponding movement. The outer profile30of the cylindrical cam29provides a two-way movement of the pistons16,17, wherein lifting of the profile30of the cylindrical cam29corresponds to a stroke of the piston16,17from the topmost position to the lowest most position and vice versa, respectively, for a ½ turn of the cam18. Movement of the pistons16,17is performed in the reverse order, the control mechanism6takes the backwash position (third position of the control mechanism,FIG. 5). After backwashing is performed, the cam mechanism18is rotated with a corresponding movement of the pistons16,17(the second position of the control mechanism,FIG. 4). During the water intake to the tank5for the regenerating solution, cam mechanism18stops. Further rotation of the cam mechanism18and the movement of pistons16,17brings apparatus1purifying fluid into the filtering stage. With full rotation (360°) of the cam mechanism18, control mechanism6passes through all stages in accordance with the predetermined algorithm of the apparatus1for purifying the fluid. In the claimed invention, all the elements of the control mechanism6operate in conjunction with a structure of the housing of the control mechanism6, where at least two fluid conducting cavities12and15are formed between the parts of the housing, and cavities13,14are formed between the housing part nearest to the top of the tank4for softening agent and the uppermost part of the tank4. Below is a table showing the device algorithm and position of the control mechanism at each stage of the apparatus for purifying the fluid.

Although the present invention has been described in connection with the embodiment thereof which is currently considered the most practical and preferred, it should be understood that the invention is not limited to the disclosed embodiments, but rather cover various modifications and variations within the spirit and scope of the appended claims.