Liquid treatment module with a recirculation flow

Abstract

A liquid treatment module (2), configured for ultraviolet (UV)-light treatment of a liquid (4) flowing through a first treatment chamber (6) defined as a first elongated circumferential hollow cavity (8) between an outer surface (10) of a first translucent inner sleeve (12) and an inner surface (16) of a first outer sleeve (18) configured to enclose said first translucent sleeve (12). The inner sleeve (12) is arranged to protect and include a UV-light treatment lamp (14). The module comprises a module inlet connection (20) configured to receive liquid to be treated and a module outlet connection (22) configured to expel liquid treated by the liquid treatment module. The module comprises: first liquid flow guiding members (24) configured to guide and direct a liquid flow (26) from said module inlet connection (20) into said first treatment chamber (6), second liquid flow guiding members (28) configured to guide and direct a liquid flow (30) from said first treatment chamber (6) into a second treatment chamber (32), and third liquid flowing guiding members (34) configured to guide and direct a liquid recirculation flow (36) from said second treatment chamber (32) back into the first treatment chamber (6) again.

Claims

1. A liquid treatment module, configured to enable ultraviolet (UV)-light treatment of a liquid flowing through a first treatment chamber defined as a first elongated circumferential hollow cavity between an outer surface of a first translucent inner sleeve and an inner surface of a first outer sleeve configured to enclose the first translucent inner sleeve, the first translucent inner sleeve configured to protect and include a UV-light treatment lamp, the liquid treatment module comprising: a module inlet connection configured to receive the liquid into the liquid treatment module to be treated; a module outlet connection configured to expel the liquid subsequent to treatment of the liquid by the liquid treatment module; a guiding part configured to guide and direct a first liquid flow of the liquid from the module inlet connection into the first treatment chamber; a guiding surface configured to guide and direct a second liquid flow of the liquid from the first treatment chamber into a second treatment chamber; and a separate guiding surface configured to guide and direct a liquid recirculation flow of the liquid from the second treatment chamber back into the first treatment chamber again to establish recirculation between the first treatment chamber and the second treatment chamber within the liquid treatment module; and a recirculation connection configured to direct and guide the liquid recirculation flow of the liquid from the second treatment chamber into the first treatment chamber again, wherein a mixing zone is established in connection to the module inlet connection where an injected flow of the liquid meets the liquid recirculation flow of the liquid, wherein the liquid treatment module further includes particles within the first treatment chamber and the second treatment chamber, the particles configured to flow with the liquid through the first treatment chamber and the second treatment chamber, the particles including abrasive particles configured to remove fouling at surfaces of the first treatment chamber and the second treatment chamber, scaling at the surfaces of the first treatment chamber and the second treatment chamber, or fouling and scaling at the surfaces of the first treatment chamber and the second treatment chamber, wherein the liquid treatment module further includes a filter member between the second treatment chamber and the module outlet connection, the filter member further between the recirculation connection and the module outlet connection, the filter member configured to prevent the particles from escaping from the first treatment chamber and the second treatment chamber through the module outlet connection, such that the particles recirculate between the first treatment chamber and the second treatment chamber with the liquid recirculation flow, the filter member further configured to allow the liquid to flow out from the first treatment chamber and the second treatment chamber through the module outlet connection.

2. The liquid treatment module according to claim 1, wherein the second treatment chamber is a second elongated circumferential hollow cavity between an outer surface of a second translucent inner sleeve and an inner surface of a second outer sleeve configured to enclose the second translucent inner sleeve, the second translucent inner sleeve configured to protect and include a separate UV-light treatment lamp.

3. The liquid treatment module according to claim 1, wherein the second treatment chamber is a second elongated circumferential hollow cavity between an outer surface of the first outer sleeve and an inner surface of a housing member.

4. The liquid treatment module according to claim 3, wherein the first outer sleeve is translucent, and the liquid treatment module is configured to subject the liquid to UV-light treatment in both the first treatment chamber and the second treatment chamber.

5. The liquid treatment module according to claim 1, wherein the inner surface of the first outer sleeve is inherently UV-light reflective or includes a UV-light reflecting coating.

6. The liquid treatment module according to claim 3, wherein the guiding part is at a first part of the first treatment chamber and the second treatment chamber, and the guiding surface is at a second part of the first treatment chamber and the second treatment chamber, and the second part is opposite the first part in the liquid treatment module.

7. The liquid treatment module according to claim 6, wherein the guiding part is configured to direct the first liquid flow in a first direction, and the guiding part is essentially annular and encircles a part of the first translucent inner sleeve such that a radial distance r of the first liquid flow from the outer surface of the first translucent inner sleeve into the first treatment chamber is defined by the guiding part.

8. The liquid treatment module according to claim 1, wherein the translucent first inner sleeve and the first outer sleeve are essentially concentrically arranged around a same longitudinal axis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a cross-sectional side view schematically illustrating the liquid treatment module according to a first embodiment of the present invention.

(2) FIG. 2 shows a cross-sectional side view schematically illustrating the liquid treatment module according to a second embodiment of the present invention.

(3) FIG. 3 is a cross-sectional view along A-A in FIG. 1.

(4) FIG. 4 is a cross-sectional view along B-B in FIG. 2.

(5) FIG. 5 shows a cross-sectional side view schematically illustrating the liquid treatment module according to a variation of the first embodiment of the present invention.

(6) FIG. 6 shows a cross-sectional side view schematically illustrating the liquid treatment module according to a third embodiment of the present invention.

(7) FIG. 7 shows a cross-sectional view from above schematically illustrating the liquid treatment module according to a third embodiment of the present invention.

(8) FIG. 8 shows a cross-sectional side view schematically illustrating the liquid treatment module according to a third embodiment of the present invention.

(9) FIG. 9 shows a cross-sectional perspective side view illustrating the liquid treatment module according to a third embodiment of the present invention.

(10) FIG. 10 shows a cross-sectional side view schematically illustrating the liquid treatment module according to a variation of the third embodiment of the present invention.

DETAILED DESCRIPTION

(11) The present invention will now be described in detail with references to the appended drawings. Throughout the figures like or similar items have the same reference signs.

(12) It should be noted that the illustrations in the figures are schematic as the intention is to illustrate the basic structure of the module, e.g. the proportion between various parts is different in a real treatment module in that the vertical height probably is considerably larger than the outer diameter of the module.

(13) First, the liquid treatment module 2 will be generally described with references to the different embodiments illustrated in the figures, and in particular FIGS. 1, 5 and 8. The invention relates to a liquid treatment module 2, configured for ultraviolet (UV)-light treatment of a liquid 4 flowing through a first treatment chamber 6 defined as a first elongated circumferential hollow cavity 8 between an outer surface 10 of a first translucent inner sleeve 12 and an inner surface 16 of a first outer sleeve 18, 18 configured to enclose the first translucent sleeve 12. The first translucent inner sleeve 12 is arranged to protect and include a UV-light treatment lamp 14. The UV-light treatment lamp 14 is preferably tube-shaped, but any shape or type of UV-lamp may be used for emitting UV-light applicable for UV-light treatment.

(14) The module comprises a module inlet connection 20 configured to receive liquid to be treated and a module outlet connection 22 configured to expel liquid treated by the liquid treatment module. The liquid may be working liquid, ballast water, or any liquid that requires UV-light treatment.

(15) One important aspect of the treatment module is to achieve a prolonged UV-light treatment period which is achieved by providing recirculation within the module between the first treatment chamber and a second treatment chamber.

(16) Thus, the liquid to be treated have a longer exposure to UV-light compared to apparatuses where only one treatment chamber is provided, in that, in the treatment module the liquid is subjected to UV-light treatment in both treatment chambers.

(17) To achieve this object the module comprises first, second and third liquid flow guiding members to guide the liquid flow into the first treatment chamber, out from the first treatment chamber into the second treatment chamber and then back into the first treatment chamber.

(18) More particularly, first liquid flow guiding members 24, 24 are provided configured to guide and direct a liquid flow 26 from the module inlet connection 20 into the first treatment chamber 6. Second liquid flow guiding members 28, 28 are provided configured to guide and direct a liquid flow 30 from the first treatment chamber 6 into the second treatment chamber 32, and third liquid flowing guiding members 34, 34 configured to guide and direct a liquid recirculation flow 36 from the second treatment chamber 32, 32 back into the first treatment chamber 6 again.

(19) The mixing zone, where the liquid 4 is injected into the first treatment chamber and where the injected flow meets the recirculation flow, is approximately indicated by arrow 26. The higher flow rate of the injected liquid in comparison to the recirculation flow 36 is the basis for achieving the recirculation.

(20) A first and a second embodiment of the present invention are illustrated in FIGS. 1 and 2, respectively. In addition cross-sectional views along A-A in FIG. 1, and B-B in FIG. 2 are shown in FIGS. 3 and 4, respectively.

(21) With references to FIG. 1, the second treatment chamber 32 is defined as a second elongated circumferential hollow cavity 38 between an outer surface 40 of a second translucent inner sleeve 42 and an inner surface 44 of a second outer sleeve 46 configured to enclose the second translucent sleeve 42. The translucent inner sleeve 42 is arranged to protect and include a UV-light treatment lamp 14. The second treatment chamber is also provided with a connection to the module outlet connection 22.

(22) The second embodiment illustrated in FIG. 2 differs from the first embodiment only with regard to that the first treatment chamber is provided with a UV-light treatment lamp and the second treatment chamber is used as a return channel for flowing the liquid back into the first treatment chamber via a recirculation connection 60.

(23) The cross-sectional views A-A and B-B illustrated in FIGS. 3 and 4, respectively, show one example of the geometrical shapes of the treatment chambers. Thus, the cross-section of a treatment chamber has typically a circular shape.

(24) The treatment module according to the first and second embodiment is preferably provided with an outer housing (not shown) that encloses the treatment chambers and thereby is a robust outer protective shell for the module.

(25) A variation of the first embodiment is illustrated in FIG. 5.

(26) More particularly, first liquid flow guiding members 24 are provided and being configured to guide and direct a liquid flow 26 from the module inlet connection 20 into the first treatment chamber 6. As clearly illustrated the first liquid flow guiding members 24 is shaped to direct the liquid flow into the first treatment chamber and specifically close to the first translucent inner sleeve 12. Thus, the advantage achieved by the structure and shape of the first guiding members 24 is to avoid any liquid flow into the third liquid flow guiding members 34 from the first guiding members 24. Second liquid flow guiding members 28 are provided configured to guide and direct a liquid flow 30 from the first treatment chamber 6 into the second treatment chamber 32, and third liquid flowing guiding members 34 configured to guide and direct a liquid recirculation flow 36 from the second treatment chamber 32 back into the first treatment chamber 6 again. The second treatment chamber 32 is defined as a second elongated circumferential hollow cavity 38 between an outer surface of a second translucent inner sleeve 42 and an inner surface of a second outer sleeve 46 configured to enclose the second translucent sleeve 42. The second translucent inner sleeve 42 is arranged to protect and include a UV-light treatment lamp 14. The second treatment chamber is also provided with a connection to the module outlet connection 22.

(27) With references to FIGS. 6-9 the third embodiment of the present invention will now be described. Herein it is referred to the above general description related to all embodiments.

(28) According to this third embodiment the first outer sleeve 18 is translucent, and the second treatment chamber 32 is defined as a second elongated circumferential hollow cavity 38 between an outer surface 48 of the translucent first outer sleeve 18 and an inner surface 50 of a housing member 52, and wherein the liquid is subjected to UV-light treatment in both treatment chambers.

(29) As a variation of this third embodiment the first outer sleeve 18 is not translucent. In particular this variation is applicable when treating opaque liquids, e.g. cutting liquids, as the effect of the UV-light only exists close to the surface of the first translucent sleeve 12. Thus, according to this variation the liquid is subjected to the UV-light treatment only in the first treatment chamber.

(30) The treatment chambers 6, 32 may be vertically arranged as illustrated in the figures, but other orientations are naturally possible. The first liquid flow guiding members 24 are arranged at a first part, or a lower part if vertically arranged, of the treatment chambers, and that the second liquid flow guiding members 28 are arranged at a second part, or an upper part if vertically arranged, of the treatment chambers. To guide the liquid the first liquid flow guiding members 24 comprise a guiding part 54 configured to direct the flow in a first direction, or an upward direction. More specifically the guiding part is essentially annular and encircles a part of the first translucent inner sleeve 12 such that a radial distance r is defined for the liquid flow to flow close to the outer surface of the first translucent inner sleeve into the first treatment chamber 6.

(31) The second liquid flow guiding members 28 comprise a guiding surface 56 displaying a smooth curve, in a plane along a longitudinal axis of the lamp, having an essentially horizontal part 58, provided that the module is vertically arranged, close to an upper part of the inner sleeve to an essentially vertical part where the guiding surface meets the inner surface of the housing member 52.

(32) An outer housing 68 is provided being an outer protective enclosure of the module and that also defines fluid channels inside the module. The outer housing is provided with the module inlet connection 20 and an outlet connection 22.

(33) A recirculation connection 60, being embodied by the third liquid flow guiding members 34, is provided and being configured to direct and guide the liquid recirculation flow 36 from the second treatment chamber 32 into the first treatment chamber 6 again. The third liquid flow guiding members comprise a guiding surface displaying a smooth curve leading the liquid flow back into the first treatment chamber.

(34) With references to FIG. 6 the translucent first inner sleeve 12 and the first outer sleeve 18 are essentially concentrically arranged with regard to its longitudinal axes. In addition the housing member 52 is also concentrically arranged with regard to sleeve 12 and sleeve 18.

(35) Thus, if vertically arranged, the liquid flow enters the inner treatment chamber from below and close to the outer surface 10 of the inner sleeve 12. The liquid flows upwards, which is indicated by the arrows in the first treatment chamber. When the liquid reaches the second liquid flow guiding members it is forced outwards into the second treatment chamber where it flows downwards. The liquid may continue into the first treatment chamber again or may flow out from the second treatment chamber via an opening, preferably provided with a filter member 64 and out from the treatment module via the outlet connection 22.

(36) Preferably, and relevant for all embodiments, particles 62, and preferably abrasive particles, are provided within the first and second treatment chambers. The particles being capable to flow with the liquid through the treatment chambers, and being capable of being recirculated within the chambers. In particular and preferably the particles comprises abrasive particles capable of removing fouling/scaling at surfaces of the treatment chambers. A filter member 64 is provided, at least in connection with the module outlet connection 22, configured to prevent the particles from escaping from the treatment chambers, but allowing liquid to flow out from the chambers, through the module outlet connection 22.

(37) The size, shape, density, concentration, hardness and constitution of the particles are dependent upon the specific application of the liquid treatment module.

(38) The size of the particles is advantageously within the range of 0.5-3 mm, and they may have both rounded shapes or more cornered or edged shapes. The size, shape and density are related to the flow rate through the chambers. For example, if the flow rate is low, e.g. 1 m/s, the size and density must be lower in comparison if a higher flow rate is applied. The hardness of the particles is preferably lower than the hardness of the surfaces of the treatment chambers.

(39) The particles are preferably made from a photocatalytic material, which is advantageous in order to improve the treatment effect. In one embodiment the abrasive particles comprises titanium dioxide (TiO.sub.2). Titanium dioxide, particularly in its anatase form, is a photocatalyst under ultraviolet (UV) light. It is also possible to provide a coated particle where the core is made from one material, and a coating layer from another material. The amount of particles may be expressed in relation to the liquid volume within the treatment module, and according to one not limiting example the volume of the particles is approximately 1/100 of the liquid volume.

(40) All particles may be the same type, or a mixture of different types of particles may be used, e.g. with regard to shape, type of material, etc.

(41) Thus, it is possible to tailor the effect achieved by the particles by varying the above parameters with regard to the specific use of the treatment module, e.g. by providing a mixture of abrasive particles and particles having photocatalytic effects.

(42) Generally, the shapes of the first, second and third liquid flow guiding members 24, 24, 28, 28, 34, 34 are such that the flow of particles are optimal for removing scaling/fouling.

(43) Specifically the first liquid guiding members 24, 24 have to direct the flow of particles such that the particles are led to flow close to the outer surface 10 of the first translucent inner sleeve which is the surface subjected to highest UV-light intensity, and thus being most prone to build up scaling/fouling.

(44) This is achieved in the third embodiment by providing a small circumferential radial opening close to the outer surface of the inner sleeve 12 into the first treatment chamber where the flow rate is high which bring particles within the chamber to flow close to the surface.

(45) The module is configured to be connected to a liquid pump unit 66 arranged to pump the liquid such that it has a flow rate through the first treatment chamber. The module may be used in a wide range of flow rates where the flow rate is related to the particular use. In one exemplary application the flow rate is approximately 1 m/s. In another application the flow rate is higher than a predetermined flow rate threshold, e.g. 3 m/s and more preferred approximately 5 m/s. This high flow rate is advantageous in order to reduce or even eliminate the formation of fouling or scaling on the surfaces inside the treatment chambers, and in particular the outer surface 10 of the inner sleeve 12.

(46) FIG. 8 shows a cross-sectional side view schematically illustrating the liquid treatment module according to one embodiment of the present invention. The features of this embodiment correspond to the features described in connection with FIGS. 5 and 6 and it is referred to the above description of those figures. In the illustrated embodiment in FIG. 8, the particles 62, e.g. the abrasive particles, are provided within the first and second treatment chambers. The particles are capable of flowing with the liquid through the treatment chambers to remove fouling/scaling at surfaces of the translucent first inner and outer sleeves. As mentioned above a filter member 64 is provided configured to prevent the particles from escaping from the treatment chambers, but allowing liquid to flow out from the chambers, through a module outlet connection 22. The filter member is e.g. a mesh having openings through which the particles cannot escape.

(47) The shapes of the first, second and third flow guiding members are such that the flow of particles is optimal for removing scaling/fouling from the surfaces inside the treatment chambers and in particular from the surfaces of the translucent sleeves.

(48) UV-light promotes the formation of scaling and/or fouling. Due to the fact that the UV-light intensity is considerably higher through the inner sleeve 12 than through the first outer sleeve 18 the scaling or fouling is in particular formed at the outer surface of the inner sleeve. By providing abrasive particles together with a rather high flow rate the prevention and/or elimination of scaling/fouling is achieved.

(49) As illustrated in FIG. 8 the first flow guiding members 24 are such that the inflow of liquid into the first treatment chamber 6 creates an underpressure that brings the particles in a first direction, or an upward direction, provided that the module has a vertical orientation, close to the outer surface of the inner sleeve. The particles will then prevent the formation of fouling/scaling. The abrasive particles will preferably follow the liquid flow into the second treatment chamber where it follows the liquid flow downwards.

(50) FIG. 9 shows a cross-sectional perspective side view illustrating the liquid treatment module according to the present invention.

(51) The treatment module 2 is preferably provided with a robust outer housing 68 which e.g. may be at least partly submerged into the liquid to be treated. Mounting and connection members 70 are provided at an upper part of the housing. The mounting and connection members facilitate access to the UV-lamp 14 to provide for e.g. electrical connections. The first translucent inner sleeve 12, and the first outer sleeve 18, that together with the housing member 52 define the first and second treatment chambers 6, 32 are illustrated in the figure. The liquid to be treated enters the module via the inlet connection 20 and exits through the outlet connection 22. The filter member 64 is provided to prevent abrasive particles from escaping from the treatment module and a filter member is preferably arranged both in connection with inlet and the outlet connections.

(52) FIG. 10 shows a cross-sectional side view of an alternative embodiment of the present invention. This embodiment is based upon the embodiment disclosed in FIGS. 6 and 7, but without the recirculation aspect in that sense as described above. A prolonged treatment time period is achieved by this embodiment by providing circulation of liquid to be treated first through a first treatment chamber and then through a second treatment chamber. Thus, with references to FIG. 10 a liquid treatment module 2 is provided, configured for ultraviolet (UV)-light treatment of a liquid 4 flowing through a first treatment chamber 6 defined as a first elongated circumferential hollow cavity 8 between an outer surface 10 of a first translucent inner sleeve 12, arranged to protect and include a UV-light treatment lamp 14, and an inner surface 16 of a first outer sleeve 18 configured to enclose the first translucent sleeve 12. The module comprises a module inlet connection 20 configured to receive liquid to be treated and a module outlet connection 22 configured to expel liquid treated by the liquid treatment module.

(53) The module comprises first liquid flow guiding members 24 configured to guide and direct a liquid flow 26 from the module inlet connection 20 into the first treatment chamber 6. Second liquid flow guiding members 28 are provided configured to guide and direct a liquid flow 30 from the first treatment chamber 6 into a second treatment chamber 32. The second treatment chamber 32 is defined as a second elongated circumferential hollow cavity 38 between an outer surface 48 of the first outer sleeve 18, which is translucent, and an inner surface 50 of a housing member 52. Thereby the liquid is subjected to UV-light treatment in both treatment chambers which is advantageous in order to achieve a long treatment period. The liquid is expelled from the second treatment chamber via an optional filter member 64 and the module outlet connection 22.

(54) Further features of the first and second guiding members, and other details illustrated in FIG. 10, are defined and discussed above in the description in relation to FIG. 6.

(55) In order to improve the UV-light treatment of the liquid one or many surfaces of the treatment module subjected to UV-light emission may be inherently UV-light reflective or may be covered by a UV-light reflecting coating in order to further increase the UV-light emission of the liquid. In particular the inner surface 16 of the first outer sleeve 18, 18 is inherently UV-light reflective or comprises a UV-light reflecting coating. This is applicable to many of the embodiments disclosed above, except for a variant of the third embodiment where the first outer sleeve 18 is made from a translucent material.

(56) The present invention is not limited to the above-described preferred embodiments. Various alternatives, modifications and equivalents may be used. Therefore, the above embodiments should not be taken as limiting the scope of the invention, which is defined by the appending claims.

REFERENCE SIGNS

(57) 2 liquid treatment module 4 liquid 6 first treatment chamber 8 first elongated circumferential hollow cavity 10 outer surface 12 first translucent inner sleeve 14 UV-light treatment lamp 16 inner surface 18, 18 first outer sleeve 20 module inlet connection 22 module outlet connection 24, 24 first liquid flow guiding members 26 liquid flow 28, 28 second liquid flow guiding members 30 liquid flow 32, 32 second treatment chamber 34, 34 third liquid flow guiding members 36 liquid recirculation flow 38 second elongated circumferential hollow cavity 40 outer surface 42 second translucent inner sleeve 44 inner surface 46 second outer sleeve 48 outer surface 50 inner surface 52 housing member 54 guiding part 56 guiding surface 58 horizontal part 60 recirculation connection 62 abrasive particles 64 filter member 66 pump unit 68 outer housing 70 mounting and connection members