A liquid purification device and a method for purifying liquid with a liquid purification device

Abstract

This invention relates to a liquid purification device (1) comprising an evaporation chamber (2) connecting to an inlet conduit (3) for receiving liquid to be purified to an upper portion (9) of the evaporation chamber (2), a low-pressure source (5) connecting to the evaporation chamber (2) through a condenser conduit (6), and at least one collector member (7) for receiving condensed liquid from the condenser conduit (6). The condenser conduit (6) has an inlet for receiving vapor from the evaporation chamber (2) and a condensing section (10) arranged between the inlet and the low-pressure source (5) for condensing the vapor received through the inlet. To further enhance vaporization of the liquid received in the evaporation chamber (2), the liquid purification device (1) further comprises a spraying unit (31) arranged between the inlet conduit (3) and the evaporation chamber (2) to spray the liquid to be purified received from the inlet conduit (3).

Description

A^LIQUID^PURIFICATION^DEVICE^AND^A^METHOD^FOR^PURIFYING^ LIQUID^WITH^A^LIQUID^PURIFICATION^DEVICE BACKGROUND^OF^THE^INVENTION^ FIELD^OF^THE^INVENTION^

[0001] ^ This invention relates to a liquid purification device and a method forpurifying liquid with a liquid purification device.DESCRIPTION^OF^PRIOR^ART

[0002] In relation to liquid purification, particularly in applications relating todesalination of sea water for producing fresh water, two principle technologies arecurrently used in large scale: reverse osmosis and thermal desalination. From thetwo technologies, reverse osmosis is currently used more widely, owing to itstypically lower energy consumption when compared to thermal desalination. Inthis process, sea water is forced through a filter membrane to separate thedissolved salt, and energy is thus saved by omitting the need for heating up of thetreatable water. However, reverse osmosis technologies currently in use aresensitive to impurities of the treatable water, resulting in the need for frequentreplacement of the filter membranes and thus relatively high level of maintenanceof the water treatment systems. Also, the energy consumption of these processesis linked with the level of salinity of the treatable water.

[0003] ^ On the other hand, thermal desalination, in which the treatable water isheated up to boiling point and the resulting vapor is then cooled down andcondensed into purified water, is highly energy intensive. The environmentalimpact of thermal desalination may be decreased by utilizing renewable energysources, such as solar energy, to heat up the water, but in praxis, high amounts ofenergy from non-renewable sources are still used for the purpose.

[0004] ^ The constantly growing global demand for desalinated water, combinedwith the target of reducing the global greenhouse gas emissions, creates a demandfor increasing the yield of sea water desalination while minimizing itsenvironmental impact. Therefore, an apparent driver exists for utilizing energy-conserving solutions in relation to water desalination. The same is true also forliquid purification processes relating to separation of other types of impurities,such as other dissolved minerals and fine solid particulates from different liquids.SUMMARY^OF^THE^INVENTION

[0005] ^ An object of the present invention is to solve the above-mentioneddrawbacks and to provide a liquid purification solution enabling low energyconsumption. This object is achieved with a liquid purification device according toindependent claim 1 and a method according to independent claim 13.

[0006] ^ By connecting an evaporation chamber to a low-pressure source andproviding a spraying unit between an inlet conduit and the evaporation chamber,it is possible to obtain a low-energy purification system utilizing low pressure forliquid vaporization.

[0007] ^ Preferred embodiments of the invention are disclosed in the dependentclaims. BRIEF^DESCRIPTION^OF^DRAWINGS

[0008] ^ In the following the present invention will be described in closer detailby way of example and with reference to the attached drawings, in which

[0009] ^ Figure 1 illustrates a first embodiment of a liquid purification device,

[0010] ^ Figure 2 illustrates a second embodiment of the liquid purificationdevice,

[0011] ^ Figure 3 illustrates a third embodiment of the liquid purification device,

[0012] ^ Figure 4 illustrates a part of an evaporation chamber of the liquidpurification device of Figure 2,

[0013] ^ Figure 5 illustrates a part of an evaporation chamber of a liquidpurification device according to a fourth embodiment,

[0014] ^ Figure 6 illustrates a cross-cut section of a condenser conduit of a liquidpurification device according to a fifth embodiment, and

[0015] ^ Figure 7 illustrates a cross-cut section of a condenser conduit of theliquid purification device of Figure 2.DESCRIPTION^OF^AT^LEAST^ONE^EMBODIMENT

[0016] ^ Figure 1 illustrates schematically a first embodiment of the liquidpurification device 1, in which liquid to be purified is received to the device. Thefigure as presented is only meant to illustrate the main structural components ofthe device and their mutual arrangement, and the dimensions and shapes aspresented may deviate from said example in other embodiments of the liquid purification device 1. Also, some structurally or functionally less significant components comprised in the construction may be omitted from the figure, so asto more clearly illustrate the main technical principle of the liquid purification device 1.

[0017] ^ As seen in the example of Figure 1, the liquid purification device 1comprises an evaporation chamber 2 connecting to an inlet conduit 3 for receivingliquid to be purified to an upper portion 9 of the evaporation chamber 2. In moredetail, the liquid to be purified is in this example received to the evaporationchamber 2 through its top wall, but in other embodiments of the device, the inlet conduit 3 may also connect to the evaporation chamber 2 at another part of itsupper portion 9. As illustrated in Figure 1 with dashed lines, the liquid purificationdevice 1 further comprises a spraying unit 31 arranged between the inlet conduit3 and the evaporation chamber 2, in other words such that the liquid to be purified is guided through the spraying unit 31 as it arrives to the evaporation chamber 2.In the arrangement as disclosed, the spraying unit 31 is used for spraying the liquidto be purified received from the inlet conduit 3, such that the feed of liquid isdispersed into fine droplets as it enters the evaporation chamber 2. The benefit ofsaid arrangement is that the surface area of the liquid feed is greatly increased as compared to an arrangement utilizing a uniform stream of liquid, therebyincreasing also the rate of evaporation of the liquid. In the example of Figure 1, thespraying unit 31 comprises a conventional spraying nozzle setup, but in other embodiments, also other means of forming a liquid spray may be utilized.

[0018] ^ In the example of Figure 1, the inlet conduit 3 is formed as an elongatedpipe comprising several functional sections, and it may be arranged to, for example, receive and convey saline sea water or other liquid to be purified from the vicinityof the liquid purification device 1, or from an external conduit delivering the liquid.For this purpose, the inlet conduit 3 may be connected to a pump system providedseparately or as an integral part of the liquid purification device 1, and is preferablyprovided with a valve system for controlling the intake and possible discharge of fluid. The outer end of the inlet conduit 3 is not shown in Figure 1.

[0019] ^ The liquid purification device 1 further comprises a low-pressuresource 5 connecting to the evaporation chamber 2 through a condenser conduit 6.In other words, the condenser conduit 6, which in the example of Figure 1 is alsoformed as an elongated pipe, connects to the evaporation chamber 2 and to thelow-pressure source 5 and serves as a passage for air and vapor to be removedfrom the evaporation chamber 2 by the low-pressure source 5 during use of the liquid purification device 1. With said arrangement, the low-pressure source 5 may be used for creating sub-atmospheric pressure condition inside the evaporationchamber 2, resulting in the boiling point of the liquid inside the evaporation chamber 2 to be lowered. This, in turn, causes the amount of vaporization of the liquid to be increased, as opposed to a setup in which the same temperature conditions were maintained under normal atmospheric pressure. As opposed to conventional thermal purification methods, such as thermal desalination, the sameyield of vapor may thus be obtained with reduced consumption of energy. In thesetup as described, the low-pressure source 5 may be a vacuum pump, for example.

[0020] ^ Alternatively, the low-pressure source 5 may comprise a conventionalmeans for providing suction, such that only a minor pressure difference is created between the inside and the outside of the evaporation chamber 2. In this case, themain function of the low-pressure source 5 is not to provide a sub-atmosphericpressure condition inside the evaporation chamber 2, but rather to draw air andvaporized liquid from the chamber through the condenser conduit 6. Suchconventional suction means may comprise a suction unit similar to the units foundin conventional vacuum cleaners, for example.

[0021] ^ Figure 2 illustrates schematically a second embodiment of the liquidpurification device 1, in which liquid to be purified has been provided to the device.As in the case of Figure 1, Figure 2 is only meant to illustrate the main structuralcomponents of the device and their mutual arrangement, and some structurally orfunctionally less significant components comprised in the construction may beomitted from the figure. For example, one end wall of the evaporation chamber 2has been left out, so as to illustrate the internal structure of the chamber. In theexample of Figure 2, the evaporation chamber 2 is provided as a cylindrical container having a horizontal orientation, as opposed to the example of Figure 1 in which the cylindrical container has a vertical orientation. In both arrangements,the evaporation chamber 2 may be comprised of, for example, a plastic container.In some embodiments, also a removable inner layer may be provided to thechamber, so that any residual liquid may be easily removed from the chamber atthe end of the purification process by removing the inner layer. In this arrangement, the inner layer may comprise, for example, a plastic bag.

[0022] ^ Figures 4 and 5 illustrate a detailed view of another end of theevaporation chamber 2, wherein Figure 4 corresponds to the embodiment ofFigure 2 and Figure 5 corresponds to another embodiment of the liquid purificationdevice 1. In both examples, an end wall of the evaporation chamber 2 has been leftout so as to illustrate the internal structure of the chamber. As seen in the examplesof Figures 4 and 5, the condenser conduit 6 has an inlet 8 for receiving vapor fromthe evaporation chamber 2, namely the vapor created through vaporization of theliquid inside the evaporation chamber 2. In the arrangement of said examples, theinlet 8 is arranged to receive the vapor from the upper portion 9 of the evaporationchamber 2, whereas the liquid to be purified is gravitationally guided to fill itslower portion 4 after being sprayed to the evaporation chamber 2 through thespraying unit 31. In more detail, the inlet 8 in said examples opens to the upperportion 9 at one end of a vertically arranged end section 24 of the condenserconduit 6 and is intended to remain above the surface level of the liquid inside theevaporation chamber 2 during use of the liquid purification device 1. The inlet 8 is at the same time used for receiving the air to be removed from the evaporationchamber 2 by the low-pressure source 5, and thereby an airflow is created towardsthe inlet 8 during a startup phase of the purification process by the low-pressuresource 5 that facilitates conveying of the vapor to the condenser conduit 6.

[0023] ^ In the examples of Figures 2 to 5, the liquid purification device 1 furthercomprises an absorption layer 11 extending between the lower portion 4 and theupper portion 9 of the evaporation chamber 2. The purpose of said absorption layer11 is to further enhance vaporization of the liquid received in the evaporationchamber 2 by breaking the smooth surface of the liquid accumulated to the lowerportion 4 of the evaporation chamber 2 otherwise held in form by surface tension,thereby increasing the surface area and vaporization of the liquid. More precisely,the absorption layer 11 is positioned inside the evaporation chamber 2 at theintended vertical position of the liquid surface 23, such that the surface of the liquidis brought into contact with the absorption layer 11 during use of the liquidpurification device 1. In the examples of Figures 2 to 5, the evaporation chamber 2is provided as a substantially horizontal tube, and the intended vertical position ofthe liquid surface 23 corresponds to the horizontal middle plane of the evaporationchamber 2 where the cross-sectional surface area of the evaporation chamber 2 ismaximized. Therefore, in said examples the absorption layer 11 is provided to ahorizontal middle portion 20 of the evaporation chamber 2.

[0024] ^ In the examples of Figures 2 to 4, the absorption layer 11 comprises aplurality of vertical slats 12. Said vertical slats 12 are preferably formed of thin foil,sheet or mesh, and they may be composed of, for example, any metal alloy orpolymer found to be compatible with the liquid to be purified in a given application.The distance between adjacent vertical slats 12 is preferably 2 mm to 4 mm, so asto allow capillary action to take place between the adjacent vertical slats 12. Inother words, when the surface 23 of the liquid inside the evaporation chamber 2 isbrought into contact with the two adjacent vertical slats 12 positioned as disclosed,the liquid will rise upwards between the vertical slats 12 due to the capillary action,thereby further increasing the surface area of the liquid. This phenomenon isparticularly prominent when the liquid to be purified is water, for example salinesea water.

[0025] ^ To further promote the capillary action between the adjacent verticalslats 12, the vertical slats 12 of the embodiment of Figure 2 are also arranged toutilize electric potential difference between them. More precisely, in said exampleat least one vertical slat of the plurality of vertical slats 12 is arranged to an electricpotential value V1 that is different from an electric potential value V2 of at leastone adjacent vertical slat 12. Said arrangement may be realized by, for example,connecting said at least one vertical slat 12 to an electric circuit isolated from thesurrounding structure of the liquid purification device 1, wherein the electric circuit is arranged to the electric potential value V1 and the surrounding structure,including said at least one adjacent vertical slat 12, is arranged to the differentelectric potential value V2. One of the values V1 and V2 may represent the ambientelectric potential level, while the other value V1 or V2 may represent the electricpotential value of an external electric potential source 27, as illustrated in Figure 2.

[0026] ^ With the utilization of electric potential difference as disclosed, thenatural polarity of water may be exploited to enhance the capillary action at thevertical slats 12. More precisely, when the electric potential difference isestablished between the adjacent vertical slats 12, the positive ends of the watermolecules comprised in the water inside the evaporation chamber 2 are attractedtowards the vertical slat or slats 12 arranged to the higher negative potential V1 or V2, while the negative ends of the molecules are correspondingly attracted towards the vertical slat or slats 12 arranged to the higher positive potential V1 or V2. Thereby, the adhesive force between the surfaces of the slats 12 and the watermolecules is increased, enhancing the capillary action and thus increasing thesurface area and vaporization of the water.

[0027] ^ In other embodiments of the liquid purification device 1, the absorptionlayer 11 may also be arranged into a different form preferably having a largespecific surface area. For example, the absorption layer 11 may be formed of finegranulates or particulates, as illustrated in the example of Figure 5, such that whenthe surface 23 of the liquid inside the evaporation chamber 2 is brought intocontact with the absorption layer 11, said granulates or particulates becomesurrounded by the liquid and enable the liquid surface 23 to rise up through theabsorption layer 11 through the capillary action. In such embodiments, thegranulates or particulates forming the absorption layer 11 are preferably held inposition by a frame structure extending inside the evaporation chamber 2, so as toprevent them from scattering or falling towards the lower portion 4 of theevaporation chamber 2.

[0028] ^ As seen in the examples of Figures 1 to 3, the condenser conduit 6further comprises a condensing section 10 arranged between the inlet 8 and thelow-pressure source 5. The purpose of the condensing section 10 is to condensethe vapor received through the inlet 8 into purified liquid, and in the examples ofFigures 1 to 3, it comprises a plurality of vertical sections 14 in which the condenserconduit 6 has a substantially vertical orientation. Said condensing of the vapor intoliquid may be accomplished utilizing several different principles simultaneously orseparately, and in the embodiments of Figures 1 to 3, this is achieved by utilizingcooling of the vapor as well as a structure of the condensing section 10 inducingdroplet nucleation. In other embodiments of the liquid purification device 1, thestructure of the condensing section 10 may deviate from the examples of Figures 1to 3, and it may comprise, for example, only one vertical section 14. In someembodiments, the condensing section 10 may also comprise condensing unitsseparate from the condenser conduit 6 structure, wherein the condensing units may be connected to the condenser conduit 6 by, for example, valves.

[0029] ^ More precisely, in the examples of Figures 1 to 3 said droplet nucleation-inducing structure of the condensing section 10 is arranged such that the innerside of the condensing section 10 is provided with a nucleator material 19. In theexamples of Figures 6 and 7, which illustrate a horizontal cross-cut section of thecondenser conduit 6 at the condensing section 10, different arrangements of the nucleator material 19 are further illustrated. Said nucleator material 19 may be formed of one of granulates, particulates, sheets and mesh, as illustrated in Figure 6, and its purpose is to provide a large surface area within the condensing section10 for the vapor received from the evaporation chamber 2 to condensate on. Inother words, the nucleator material 19 provides nucleation points for inducingformation and growth of droplets of purified liquid, while simultaneously allowing passage of air and vapor being removed from the evaporation chamber 2 towardsthe low-pressure source 5. This way, the vapor may proceed through the verticalsections 14 of the condensing section 10, and the liquid content in the mixture ofair and vapor is gradually decreased at each of the vertical sections 14 as more ofthe vapor is condensed into liquid. According to a preferred embodimentillustrated in Figure 7, the nucleator material 19 comprises gravel, in other words small stone particles, so as to simultaneously provide mineralization of the otherwise mineral-deficient purified water.

[0030] ^ The arrangement as disclosed, wherein the condensing section 10 islocated before the low-pressure source 5, as viewed in the direction of the flowwithin the condenser conduit 6, enables lower energy consumption of the low-pressure source 5 as opposed to an arrangement in which the vapor is condensedonly after passing the low-pressure source 5. That is, the relatively large mass ofvapor only needs to be conveyed by the flow induced by the low-pressure source 5until the condensing section 10, thus reducing the amount of energy needed formass transfer.

[0031] ^ In the examples of Figures 2 to 5, the condenser conduit 6 furthercomprises a horizontal section 13 extending in the lower portion 4 of theevaporation chamber 2. More precisely, in said examples the horizontal section 13extends from the lower end of the vertically arranged end section 24 of the condenser conduit 6 across the length of the evaporation chamber 2. According to a preferred embodiment of the liquid purification device 1, the inner side of saidhorizontal section 13 is also provided with the nucleator material 19, analogouslyto the arrangement disclosed above in relation to the condensing section 10. Withthe arrangement as disclosed, the horizontal section 13 may act as a firstcondensing element of the condenser conduit 6, condensing a part of the vapor received through the inlet 8 of the condenser conduit 6 before it is transferred tothe condensing section 10 as disclosed above. Because the horizontal section 13extends in the lower portion 4 of the evaporation chamber 2, which during use ofthe liquid purification device 1 is filled with the liquid to be purified, thermalenergy originating from the condensation of the vapor within the horizontalsection 13 is transferred back to the liquid in the evaporation chamber 2. This, inturn, increases the temperature of the liquid and thereby further enhances its vaporization.

[0032] ^ The liquid purification device 1 further comprises at least one collectormember 7 for receiving the condensed liquid from the condenser conduit 6. Moreprecisely, in the examples of Figures 1 to 3 one collector member 7 is arrangedbelow each vertical section 14 comprised in the condensing section 10, and eachcollector member 7 comprises a sealable container 16 connecting to the verticalsection 14 through a 3-way valve 17. In this context, the term sealable means thatthe container 16 has a structure preventing any fluid flow between the container16 and its surrounding other than through the 3-way valve 17, and together withthe other structural elements of the liquid purification device 1 forms a fluid-tightentity in which the low-pressure condition created by the low-pressure source 5may be maintained. With the arrangement as disclosed, namely by arranging thecollector members 7 below each vertical section 14, gravitation-induced flow of thecondensed liquid downwards along the length of the vertical sections 14 may beutilized for receiving the liquid to the collector members 7. In other embodimentsof the liquid purification device 1, the collector members 7 may also comprise, forexample, a conduit for conveying the condensed liquid away from the liquidpurification device 1.

[0033] ^ By connecting the sealable container 16 to the vertical section 14through the 3-way valve 17 as disclosed, the liquid purification device 1 may beoperated such that no interruptions are caused by the sealable container 16becoming full and requiring replacement or emptying. More precisely, the sealablecontainers 16 may be emptied while retaining the low-pressure condition providedby the low-pressure source 5 within other parts of the liquid purification device 1,and the atmospheric pressure required for discharging the liquid from the sealablecontainer 16 may be restored simultaneously with sealably closing the fluidconnection between the condenser conduit 6 and the sealable container 16.

[0034] ^ In praxis, this is accomplished by operating the 3-way valve 17 so as toclose the fluid connection between the condenser conduit 6 and the sealable container 16 when sufficient amount of liquid has accumulated to the sealablecontainer 16, preventing further fluid flow between them. Simultaneously, a newflow pathway is opened through the 3-way valve 17 between the sealable container16 and the surrounding environment, allowing the atmospheric pressure condition to be restored within the sealable container 16. After this, the sealable container 16 may be emptied through, for example, a typical 2-way valve preferably positioned at a lower part of the sealable container 16, and the steps as disclosedthen be repeated in a reversed order so as to return the operational state of thesealable container 16. Said sufficient amount of liquid being accumulated to thesealable containers 16 may be verified using, for example, a sensor, such as anoptical sensor, and the operation of the 3-way valve 17 and the emptying of thesealable container 16 as disclosed may be performed automatically based onsignals transmitted by said sensor.

[0035] ^ In some embodiments of the liquid purification device 1, the sealablecontainer or containers 16 may be provided to the device as fixed structures, whilein other embodiments, they may comprise removable containers facilitating thetransport and distribution of the purified liquid together with the containers. In theexamples of Figures 1 to 3, the liquid purification device 1 further comprises acollector container 25 located below the sealable containers 16, into which theaccumulated liquid is passed from each sealable container 16 through a 2-wayvalve 26 located between each sealable container 16 and the collector container25. With the arrangement as described, transportation of the purified liquid maybe accomplished either by utilizing a transportation conduit connecting to thecollector container 25 or by detaching and transporting the collector container 25 together with the liquid.

[0036] ^ In the examples of Figures 1 to 3, the liquid purification device 1 furthercomprises a condensation chamber 21 sealably connecting to the condenserconduit 6 after the low-pressure source 5. The condensation chamber 21 in saidexamples is an over-pressure chamber, and the low-pressure source 5 is arrangedto pressurize the chamber by providing remaining vapor from the condensingsection 10 to the chamber. With the arrangement as disclosed, the remaining vapormay be condensed into purified liquid by utilizing over-pressure, in other wordssuch that the boiling point of the vapor is increased sufficiently to force it into liquidstate.

[0037] ^ In more detail, the condensation chamber 21 may be provided with anexhaust valve 29 and a pressure valve, such that at a startup phase of the liquidpurification device 1, the exhaust valve 29 is open allowing air flow to bypass thecondensation chamber 21. Once air inside the device has been depleted and onlyvapor remains, the exhaust valve 29 may then be closed and the outgoing fluid flowthereby directed to the condensation chamber 21. Thereby, the pressure in thecondensation chamber 21 is increased to a level set to the pressure valve, forcingthe remaining vapor to condensate. In the examples of Figures 1 to 3, thecondensation chamber 21 is connected to a sealable container 16 in a wayanalogous to the arrangement disclosed above in relation to the vertical sections 14, so as to collect the resulting purified liquid.

[0038] ^ In the examples of Figures 1 to 3, the inlet conduit 3 has a helical section15 surrounding the vertical section 14 of the condenser conduit 6 at each of thevertical sections 14. More precisely, each vertical section 14 in said examples ispositioned in the middle of a helical coil forming the helical section 15, and thehelical section 15 forms a contact with the vertical section 14, namely the outersurface of the condenser conduit 6. With the arrangement as disclosed, the liquidto be purified arriving to the evaporation chamber 2 though the inlet conduit 3 isarranged to receive thermal energy from the vertical sections 14, said thermalenergy being originated from the condensation of the vapor within the verticalsections 14 though an exothermic process. In other words, the entity comprised ofthe vertical sections 14 and the helical sections 15 acts as a heat exchanger, pre-heating the liquid arriving to the evaporation chamber 2 and cooling down thevapor within the vertical sections 14. Thereby, vaporization of the liquid inside theevaporation chamber 2, as well as condensation of the vapor within the verticalsections 14 is enhanced, and the consumption of energy of the liquid purificationdevice 1 is reduced. Analogously, in the examples of Figures 1 to 3 a helical section15 is also arranged to surround the condensation chamber 21, allowing the samebenefit to be obtained as disclosed in relation to the vertical sections 14.

[0039] ^ In other embodiments of the liquid purification device 1, the helicalsections 15 may be provided only to some of the vertical sections 14, such thatpreferably at least one vertical section 14 is provided with the helical section 15. Inyet other embodiments of the liquid purification device 1, a dedicated conduit for a cooling liquid may be provided to the device, said conduit having a helical sectionsurrounding one or more of the vertical sections 14 independently orsimultaneously with the helical sections 15 of the inlet conduit 3. In theseembodiments, said cooling liquid may comprise, for example, liquid from the samesource as the one received to the evaporation chamber 2, such as sea water.

[0040] ^ In the examples of Figures 2 to 5, the liquid purification device 1 furthercomprises an auxiliary evaporator member 18 provided to the lower portion 4 ofthe evaporation chamber 2. In said examples, the auxiliary evaporator member 18comprises a conduit element 28, wherein a dedicated heating fluid, such as hotwater, is circulated so as to provide additional thermal energy to the liquidaccumulated to the evaporation chamber 2. With the arrangement as disclosed, thetemperature of the liquid to be purified may be further increased, if needed, compensating for any loss of thermal energy resulting from the evaporation of theliquid. In arrangements in which the auxiliary evaporator member 18 receivesenergy from a renewable energy source, for example through a solar powerelement, said providing of additional thermal energy to the liquid may beperformed without increased greenhouse gas emissions. In other embodiments ofthe liquid purification device 1, the auxiliary evaporator member 18 may alsocomprise one of an electric heating element, a sonicator element and anelectromagnetic radiation element, and said elements may be included in theconstruction separately or in any combination with each other.

[0041] ^ In the examples of Figures 2 and 3, the liquid purification device 1further comprises a sensor device 22 provided to the evaporation chamber 2, saidsensor device 22 being arranged to monitor the surface level of the liquid receivedto the evaporation chamber 2. More precisely, in said examples the sensor device22 monitors the elevation of the liquid surface 23 inside the evaporation chamber2, and when the surface level reaches a predetermined target height at thehorizontal middle portion 20 of the evaporation chamber 2, the sensor device 22 isarranged to transmit a signal so as to suspend the intake of liquid to the liquid purification device 1. Said suspending of the liquid intake may be accomplished by,for example, closing a valve provided to the inlet conduit 3 or by stopping a pumpsystem provided to the liquid purification device 1 for providing the flow of liquidto be purified to the evaporation chamber 2. The sensor device 22 may comprise, for example, an optical sensor.

[0042] ^ The sensor device 22 according to Figures 2 and 3 may be arranged tomonitor also the salinity level of the liquid received to the evaporation chamber 2.That is, said salinity level, which is particularly relevant in embodiments wherein the liquid to be purified comprises saline sea water, is bound to increase as a result of a part of the liquid being vaporized, and the resulting highly saline residual waterneeds to be removed from the evaporation chamber 2 after a predetermined levelof salinity has been reached. Said residual water, namely brine, may then beremoved from the evaporation chamber 2 based on a signal transmitted by thesensor device 22, for example by opening an outlet valve favourably provided to the lower portion 4 of the evaporation chamber 2. The liquid purification device 1 may also be provided with an additional container 30 for receiving the brine from the evaporation chamber 2, as illustrated in Figure 3, and said additional container30 may also be connected to the low-pressure source 5 for providing a low-pressure condition to the inside of the container. With the arrangement as disclosed, removing all remaining water from the brine becomes possible, such that only solidified salt is produced as a side stream by the operation of the liquid purification device 1.

[0043] ^ With a liquid purification device 1 according to the invention, liquidmay be purified by first receiving the liquid to be purified to the upper portion 9 ofthe evaporation chamber 2 and by then spraying the liquid to be purified. Saidreceiving of the liquid may be performed, for example, as disclosed above, namelyby utilizing the inlet conduit 3 that may be connected to, for example, a pump system. In embodiments where the absorption layer 11 is utilized, the process maybe continued by arranging the surface 23 of the liquid accumulated to the lowerportion 4 of the evaporation chamber 2 in contact with the absorption layer 11. Asa next step, pressure inside the evaporation chamber 2 is reduced to producevapor, which may be performed utilizing the low-pressure source 5 as disclosed,for example. As disclosed above, said pressure reduction may be only performed so as to draw air and vaporized liquid from the evaporation chamber 2 through the condenser conduit 6, rather than providing a sub-atmospheric pressure conditioninside the evaporation chamber 2. By arranging the surface 23 of the liquid incontact with the absorption layer 11, vaporization of the liquid may be furtherenhanced, as disclosed above. In embodiments of the liquid purification device 1 inwhich the absorption layer 11 comprises the plurality of vertical slats 12, also theelectric potential difference between adjacent vertical slats 12 as disclosed may beused, for example by switching on an external electric potential source connecting to at least one of the vertical slats 12.

[0044] ^ As a following step, the vapor is received to the condenser conduit 6,which may be performed simultaneously with said reduction of pressure inside theliquid purification device 1 by allowing the vapor to be conveyed by the fluid flowinduced by the low-pressure source 5. After this, the vapor in the condenserconduit 6 is condensed to produce purified liquid. Said condensing of the vapor inthe condenser conduit 6 may comprise cooling the vapor, for example by utilizinga condensing section 10 setup provided with the helical section or sections 15 ofthe inlet conduit 3 as disclosed above. Alternatively, said condensing of the vapormay be performed relying on condensation occurring as a result of a nucleation -inducing structure, for example in the form of the nucleator material 19 asdisclosed above, being provided to the condenser conduit 6.

[0045] ^ The method as disclosed may further comprise the step of receiving thepurified liquid to the collector member 7, which may comprise, for example, thesealable container 16 as disclosed above. Then, the 3-way valve 17 between thecondenser conduit 6 and the collector member 7 may be sealably closed to restorepressure in the collector member 7. In this context, said restoring pressure refersto the atmospheric pressure condition being restored in the collector member 7,which in the case of the 3-way valve 17 being used may take place simultaneouslywith the closing of the 3-way valve 17, as disclosed above. With said arrangement,the liquid accumulated in the collector member 7 may be extracted from the liquidpurification device 1 without allowing the low-pressure condition inside the deviceto be lost or compromised, and simultaneously enabling the collector member 7 toreach a state in which extracting liquid from the collector member 7 becomespossible, namely the atmospheric pressure condition.

[0046] ^ It is to be understood that the above description and the accompanyingfigures are only intended to illustrate the present invention. It will be obvious to a person skilled in the art that the invention can be varied and modified without departing from the scope of the invention.

Claims

CLAIMS:

1. A liquid purification device (1) comprising: an evaporation chamber (2) connecting to an inlet conduit (3) forreceiving liquid to be purified to an upper portion (9) of the evaporation chamber(2), alow-pressure source (5) connecting to the evaporation chamber (2)through a condenser conduit (6), and at least one collector member (7) for receiving condensed liquid from the condenser conduit (6), wherein the condenser conduit (6) has an inlet (8) for receiving vapor from theevaporation chamber (2) and a condensing section (10) arranged between the inlet(8) and the low-pressure source (5) for condensing the vapor received through theinlet (8), c h a r a c t e r i z e d ^ in that the liquid purification device (1) furthercomprises: aspraying unit (31) arranged between the inlet conduit (3) and theevaporation chamber (2) to spray the liquid to be purified received from the inletconduit (3).

2. The liquid purification device (1) according to claim 1,c h a r a c t e r i z e d ^ in that the liquid purification device (1) further comprisesan absorption layer (11) extending between a lower portion (4) and the upperportion (9) of the evaporation chamber (2) for forming a contact with a surface(23) of the liquid to be purified accumulated to the lower portion (4) of theevaporation chamber (2).

3. The liquid purification device (1) according to claim 2,c h a r a c t e r i z e d ^ in that the absorption layer (11) comprises a plurality ofvertical slats (12), wherein the distance between adjacent vertical slats (12) is 2mm to 4 mm.

4. The liquid purification device (1) according to claim 3,c h a r a c t e r i z e d ^ in that at least one vertical slat (12) of the plurality ofvertical slats (12) is arranged to an electric potential value (V1) that is differentfrom an electric potential value (V2) of at least one adjacent vertical slat (12).

5. The liquid purification device (1) according to any one of the claims1 to 4, c h a r a c t e r i z e d ^ in that the condenser conduit (6) has a horizontalsection (13) extending in the lower portion (4) of the evaporation chamber (2).

6. The liquid purification device (1) according to any one of the claims1 to 5, c h a r a c t e r i z e d ^ in that the condensing section (10) of the condenserconduit (6) comprises at least one vertical section (14), and the at least one collector member (7) is arranged below the at least one vertical section (14).

7. The liquid purification device (1) according to claim 6,c h a r a c t e r i z e d ^ in that the inlet conduit (3) has at least one helical section(15) surrounding the at least one vertical section (14) of the condenser conduit (6).

8. The liquid purification device (1) according to claim 6 or 7,c h a r a c t e r i z e d ^ in that the at least one collector member (7) comprises asealable container (16), wherein the sealable container (16) connects to the at leastone vertical section (14) of the condenser conduit (6) through a 3-way valve (17).

9. The liquid purification device (1) according to any one of the claims1 to 8, c h a r a c t e r i z e d ^ in that the liquid purification device (1) furthercomprises an auxiliary evaporator member (18) provided to the lower portion (4)of the evaporation chamber (2), wherein the auxiliary evaporator member (18)comprises one of an electric heating element, a conduit element, a sonicator element and an electromagnetic radiation element.

10. The liquid purification device (1) according to any one of the claims1 to 9, c h a r a c t e r i z e d ^ in that an inner side of the condensing section (10)of the condenser conduit (6) is provided with a nucleator material (19), whereinthe nucleator material (19) is formed of one of granulates, particulates, sheets andmesh.

11. The liquid purification device (1) according to any one of the claims1 to 10, c h a r a c t e r i z e d ^ in that the liquid purification device (1) furthercomprises at least one condensation chamber (21) sealably connecting to thecondenser conduit (6) after the low-pressure source (5), wherein the low-pressuresource (5) is arranged to pressurize the condensation chamber (21).

12. The liquid purification device (1) according to any one of the claims1 to 11, c h a r a c t e r i z e d ^ in that the liquid purification device (1) furthercomprises a sensor device (22) provided to the evaporation chamber (2), wherein the sensor device (22) is arranged to monitor at least one of a surface level and a salinity level of the liquid received to the evaporation chamber (2).

13. A method for purifying liquid with a liquid purification device (1),c h a r a c t e r i z e d ^ in that the method comprises the steps of:receiving liquid to be purified to an upper portion (9) of an evaporationchamber (2),spraying the liquid to be purified, reducing pressure inside the evaporation chamber (2) to produce vapor, receiving the vapor to a condenser conduit (6), and condensing the vapor in the condenser conduit (6) to produce purifiedliquid.

14. The method according to claim 13, c h a r a c t e r i z e d ^ in thatthe method further comprises the step of: arranging a surface (23) of the liquid to be purified accumulated to alower portion (4) of the evaporation chamber (2) in contact with an absorptionlayer (11).

15. The method according to claim 13 or 14, c h a r a c t e r i z e d ^ inthat the method further comprises the steps of:receiving the purified liquid to a collector member (7), and sealably closing a 3-way valve (17) between the condenser conduit (6)and the collector member (7) to restore pressure in the collector member (7).

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