METHOD AND APPARATUS FOR REMOVAL OF CLARIFIED LIQUID

Abstract

The invention relates first of all to a method for removal of clarified liquid from a liquid basin (N), such as a clarification basin or like, with an apparatus, by means of which clarified liquid is being removed by using a liquid exhaust arrangement (2) and a collecting arrangement coupled therewith. The liquid exhaust arrangement comprises one or more exhaust passages (2a1), existing beneath surface (y) of the liquid basin one after another in longitudinal direction (s) of the liquid basin and comprising a profile with an essentially closed cross section, such as a pipe, channel or like, each passage having a perforation (R) to make possible flow of liquid inside the same. Functioning of the liquid exhaust arrangement is being controlled according to the circumstances, such as due to surface alteration in the liquid basin, by adjusting the amount of liquid to be removed by the exhaust passage (2a1) by changing a flow cross section area beneath the surface (y) of the liquid basin of an open overflow edge (2a2y) of exhaust organs (2a2), being coupled with the perforation (R) in the exhaust passage and having a cross section expanding towards outer end thereof, which is carried out by turning (w) the exhaust organs (2a2) with respect to longitudinal axis (p1) of the exhaust passage (2a1). The invention also relates to an apparatus operating according to the method.

Claims

1. Method for removal of clarified liquid from a liquid basin, such as a clarification basin or like, with an apparatus, by means of which clarified liquid is being removed by using a liquid exhaust arrangement and a collecting arrangement coupled therewith, whereby the liquid exhaust arrangement comprises one or more exhaust passages, existing beneath surface of the liquid basin one after another in longitudinal direction of the liquid basin and comprising a profile with an essentially closed cross section, such as a pipe, channel or like, each passage having a perforation to make possible flow of liquid inside the same, and whereby functioning of the liquid exhaust arrangement is being controlled according to the circumstances, such as due to surface alteration in the liquid basin, by adjusting the amount of liquid to be removed by an exhaust passage by changing a flow cross section area beneath the surface of the liquid basin of an open overflow edge of exhaust organs, being coupled with the perforation in the exhaust passage and having a cross section expanding towards outer end thereof, which is carried out by turning the exhaust organs with respect to longitudinal axis of the exhaust passage, wherein, clarified liquid is being removed in a spot-like manner at different points in crosswise direction by at least two exhaust passages, being placed one after another in the longitudinal direction of the liquid basin, whereby the exhaust organs in each exhaust passage are placed, when viewed on a plane of the liquid basin, in an overlapping manner with respect to each other.

2. Method according to claim 1, wherein in order to prevent gathering of substance on the surface of the liquid basin, liquid on the surface is being removed by one or more exhaust passages, the exhaust organs in which are in a differing position, such as oppositely directed, with respect to other exhaust organs in the same exhaust passage or in other exhaust passages.

3. Method according to claim 1, wherein, removal of surface liquid through one or more exhaust passages is being interrupted by turning the exhaust organs of the exhaust passage in question in a vertical position reaching essentially above the surface of the liquid basin.

4. Apparatus for removal of clarified liquid from a liquid basin, such as a clarification basin or like, which apparatus has a liquid exhaust arrangement for removing of clarified liquid and a collecting arrangement coupled therewith, whereby the liquid exhaust arrangement comprises one or more exhaust passages, existing beneath surface of the liquid basin one after another in longitudinal direction of the liquid basin and comprising a profile with an essentially closed cross section, such as a pipe, channel or like, each passage having a perforation to make possible flow of liquid inside the same, and wherein the apparatus comprises an adjustment arrangement for controlling functioning of the liquid exhaust arrangement according to the circumstances, such as due to surface alteration in the liquid basin, which adjustment arrangement comprises mechanical and/or auxiliary powered driving means in order to adjust the amount of liquid to be removed by an exhaust passage by changing a flow cross section area beneath the surface of the liquid basin of an open overflow edge of exhaust organs, being coupled with the perforation in the exhaust passage and having a cross section expanding towards outer end thereof, which is carried out by turning the exhaust organs with respect to longitudinal axis of the exhaust passage, wherein, the apparatus comprises at least two exhaust passages, being placed one after another in the longitudinal direction of the liquid basin, whereby the exhaust organs in each exhaust passage are placed, when viewed on a plane of the liquid basin, in an overlapping manner with respect to each other in order to remove clarified liquid in a spot-like manner at different points in crosswise direction.

5. Apparatus according to claim 4, wherein, the exhaust passage comprises exhaust organs, being fastened immovably to the perforation that exists in the exhaust passage in one and the same line, wherein the exhaust organs are arranged movable by rotating the exhaust passage in a vertical plane along the longitudinal direction of the liquid basin around longitudinal axis thereof.

6. Apparatus according to claim 4 or 5, wherein, the exhaust passage belonging thereto has exhaust organs reaching essentially above the surface of the liquid basin in order to interrupt removal of surface liquid by turning the exhaust passage in question in a vertical position.

7. Apparatus according to claim 4, wherein, the adjustment arrangement comprises control and adjustment automation operable through auxiliary powered actuators in order to adjust turning motion of the exhaust organs, such as the rotating motion of each exhaust passage, according to the circumstances, such as in order to control the surface level in the liquid basin and/or flow circumstances therein, by using the successive exhaust passages and/or the exhaust organs therein in positions differing from each other.

8. Apparatus according to claim 4, wherein, it comprises a scraper bar arrangement, which consists of one or more scraper bars, existing in crosswise direction one after another in the longitudinal direction of the liquid basin and being arranged movable with a circulating motion in opposite directions in the liquid basin by movement means such as one or more chains coupled in connection therewith that are driven through a drive wheel and idle wheel assembly or like.

Description

[0019] Other advantageous embodiments of the method and apparatus according to the invention have been presented in the dependent claims directed thereto.

[0020] In the following description the invention is being depicted in detail with reference to the appended drawings, whereby

[0021] in FIGS. 1a, 1b

[0022] are shown a partly (for the part of chains and scraper bars) stripped view from above and a longitudinal cross section view of a traditional liquid basin, in which the removal of clarified liquid is carried out according to prior art,

[0023] in FIGS. 2a, 2b

[0024] are shown a partly stripped view from above and a longitudinal cross section view of an alternative solution with respect to the one shown in FIGS. 1a, 1b in removal of clarified liquid according to prior art,

[0025] in FIGS. 3a, 3b

[0026] are shown a partly stripped view from above and a longitudinal cross section view of an advantageous liquid basin, in which the removal of clarified liquid is carried out according to the invention,

[0027] in FIG. 4

[0028] is shown an enlarged detail of point IV in FIG. 3a,

[0029] in FIG. 5

[0030] is shown a cross section of an advantageous embodiment according to the invention, when viewed from the front of an exhaust passage in the liquid basin,

[0031] in FIG. 6

[0032] is shown a perspective view of an advantageous pipe-like exhaust passage belonging to an apparatus according to the invention and partly funnel-like exhaust organs, being coupled therewith, and

[0033] in FIGS. 7a, 7b

[0034] is shown a front view of the embodiment according to FIG. 6 in a vertical position and in a tilted position.

[0035] The invention relates first of all to a method for removal of clarified liquid from a liquid basin N, such as a clarification basin or like, with an apparatus, by means of which clarified liquid is being removed by using a liquid exhaust arrangement 2 and a collecting arrangement 2b coupled therewith. The liquid exhaust arrangement comprises one or more exhaust passages 2a1, existing beneath surface y of the liquid basin one after another in longitudinal direction s of the liquid basin and comprising a profile with an essentially closed cross section, such as a pipe, channel or like, each passage having a perforation R to make possible flow of liquid inside the same. Functioning of the liquid exhaust arrangement 2 is being controlled according to the circumstances, such as due to surface alteration in the liquid basin, by adjusting the amount of liquid to be removed by the exhaust passage 2a1 by changing a flow cross section area beneath the surface y of the liquid basin of an open overflow edge 2a2y of exhaust organs 2a2, each one of which being coupled with the perforation R in the exhaust passage and having a cross section expanding towards outer end thereof, which is carried out e.g. on the principle shown in FIGS. 3b and 7b by turning w the exhaust organs 2a2 with respect to longitudinal axis p1 of the exhaust passage 2a1.

[0036] In the method according to the invention especially with reference to FIGS. 3a, 3b and 4, clarified liquid is being removed in a spot-like manner at different points in crosswise direction p by at least two exhaust passages 2a1, being placed one after another in the longitudinal direction s of the liquid basin, whereby the exhaust organs 2a2 in each exhaust passage 2a1 are placed, when viewed in a plane of the liquid basin, in an overlapping manner with respect to each other.

[0037] In FIGS. 3a, 3b is shown an advantageous embodiment of the method according to the invention in a clarification tank that is carried out according to traditional technique, where, according to FIGS. 1a, 1b and 2a, 1b showing prior art, a scraper bar arrangement 1 has been utilized, which consists of one or more in the longitudinal direction s of the liquid basin consecutive scraper bars 1a, being is arranged movable with a circulating motion in opposite directions in the liquid basin by movement means 1b, such as by one or more chains 1b2 being fastened thereto and driven by a drive wheel and an idle wheel assembly 1b1 or the like.

[0038] As an advantageous embodiment of the method according to the invention, in order to prevent collecting of substance on the surface of the liquid basin, liquid on the surface is being removed by one or more exhaust passages 2a1, the exhaust organs 2a2 in which are in a differing position, such as oppositely directed, with respect to other exhaust organs in the same exhaust passage or in other exhaust passages. The above mentioned principle manifests itself especially in FIGS. 3a, 3b, according to which, the exhaust organs 2a2 of the hindmost exhaust passage 2a1 at the back wall of the liquid basin N are tilted towards the back wall, wherein the meaning is especially to prevent material from gathering on the surface of the liquid basin in connection with the back wall, whereby due to bumping into which the surface liquid might remain whirling and collecting material on its surface. Thanks to the method according to the invention, it is thus also possible to adjust the flow speed in different parts of the liquid basin according to need by using e.g. consecutive exhaust passages and/or the exhaust organs therein in different positions with respect to each other.

[0039] As a furthermore advantageous embodiment of the method according to the invention, removal of surface liquid through one or more exhaust passages 2a1 is being interrupted by turning the exhaust organs 2a2 of the exhaust passage 2a1 in question in accordance to what has been shown in FIG. 7a in a vertical position II reaching essentially above the surface y of the liquid basin. In this manner, it is possible to control the fluctuation of liquid surface especially in situations, where the liquid surface is at its lowest, wherein surface liquid can be removed if necessary e.g. by only using the hindmost exhaust passage and possibly in its backwards tilted position.

[0040] On the other hand, the invention also relates to an apparatus for removal of clarified liquid from a liquid basin N, such as a clarification basin or like, which apparatus has a liquid exhaust arrangement 2 for removing of clarified liquid and a collecting arrangement 2b coupled therewith. The liquid exhaust arrangement comprises one or more exhaust passages 2a1, existing beneath surface y of the liquid basin one after another in longitudinal direction s of the liquid basin and comprising a profile with an essentially closed cross section, such as a pipe, channel or like, each passage having a perforation R to make possible flow of liquid inside the same. The apparatus comprises an adjustment arrangement X for controlling functioning of the liquid exhaust arrangement 2 according to the circumstances, such as due to surface alteration in the liquid basin, which adjustment arrangement comprises mechanical and/or auxiliary powered driving means (which are, however, not shown in the figures) in order to adjust the amount of liquid to be removed by the exhaust passage 2a1 by changing a flow cross section area beneath the surface y of the liquid basin of an open overflow edge 2a2y of exhaust organs 2a2, being coupled with the perforation R in the exhaust passage and having a cross section expanding towards outer end thereof, which is carried out by turning w the exhaust organs 2a2 e.g. on the principle manifesting itself in FIGS. 3b and 7b with respect to longitudinal axis p1 of the exhaust passage 2a1.

[0041] The liquid removal arrangement 2 of the apparatus according to the invention comprises at least two exhaust passages 2a1, being placed one after another in the longitudinal direction s of the liquid basin, whereby the exhaust organs 2a2 in each exhaust passage 2a1 are placed, when viewed on a plane of the liquid basin, in an overlapping manner with respect to each other in order to remove clarified liquid in a spot-like manner at different points in crosswise direction p. Thus, an undisrupted and in a uniform manner continuing flow way for the surface liquid over the whole length of the clarifying section is made possible and kept as constant as possible.

[0042] As an advantageous embodiment of the apparatus according to the invention, the exhaust passage 2a1 belonging thereto comprises exhaust organs 2a2, being fastened immovably to the perforation R that exists in the exhaust passage in one and the same line, wherein the exhaust organs are arranged movable by rotating w the exhaust passage 2a1 in a vertical plane along the longitudinal direction s of the liquid basin around longitudinal axis p1 thereof.

[0043] As a furthermore advantageous embodiment of the apparatus according to the invention, the exhaust passage 2a1 belonging thereto has exhaust organs 2a2 reaching essentially above the surface y of the liquid basin in order to interrupt removal of surface liquid by turning the exhaust passage 2a1 in question in a vertical position II according to FIG. 7a.

[0044] As a furthermore advantageous embodiment of the apparatus according to the invention, the adjustment arrangement X comprises control and adjustment automation operable through auxiliary powered actuators in order to adjust turning motion of the exhaust organs 2a2, such as the rotating motion w of each exhaust passage 2a1, according to the circumstances, such as in order to control alteration of the surface level in the liquid basin and/or flow circumstances therein, by using the successive exhaust passages and/or the exhaust organs therein in positions differing from each other.

[0045] Particularly in FIGS. 3a, 3b is shown also an exhaust arrangement 2c, which, however, needs not to be utilized in all contexts. In addition, in FIG. 3b is shown a guide L in connection with the back wall of the liquid basin, the purpose of which is, when needed, to prevent the material on the bottom from drifting up to the liquid surface in connection with the back wall of the liquid basin due scraper bars 1a going down to the bottom of the liquid basin after an idle wheel 1b1.

[0046] Furthermore, in the advantageous embodiment shown especially in FIGS. 3a, 3b, the apparatus comprises a scraper bar arrangement 1, which consists of one or more scraper bars 1a, existing in crosswise direction p one after another in the longitudinal direction s of the liquid basin and being arranged movable with a circulating motion in opposite directions in the liquid basin by movement means 1b, such as one or more chains 1b2 coupled in connection therewith that are driven by a drive wheel and an idle wheel assembly or like.

[0047] It is clear that the invention is not limited to the embodiments presented or described above, but instead it can be modified within the basic idea of the invention in very many ways depending on the needs at any given time. Thus, the invention also relates at its widest to basins, which do not necessarily have any kind of an arrangement for removal of surface scum or a scraper bar arrangement e.g. according to FIGS. 3a, 3b. It is possible to vary the technical implementation of the overflow arrangement for the removal of surface scum, if such is, however, needed. Naturally there are also different kinds of scraper bar constructions, in addition to which in connection with the same can be used e.g. urethane based or the like filling materials etc. Thanks to the advantageous operating principle of the invention, it is, according to what has been said above, possible to manufacture the liquid removing machinery from the most varied materials with the most varied manufacturing techniques using plastic, metal or composite materials or if necessary or, if the circumstances so demand, by using more traditional metal or concrete structures etc. The principle according to the invention may naturally also be exploited by using longitudinal exhaust passages in the liquid basin, the exhaust organs therein turning in transverse plane with respect to the longitudinal direction of the liquid basin. In this type of a solution, it is furthermore possible to utilize exhaust passages that are coupled only from one end thereof with the back wall of the liquid basin.