APPARATUS FOR DISSOLVING GAS INTO A LIQUID AND METHOD FOR PRODUCING THE SAME

Abstract

An apparatus for dissolving gas into a liquid, comprising a housing with an inlet opening for the liquid and an outlet opening for the liquid, and a blade unit arranged inside the housing in a small cross section area between the inlet opening and the outlet opening, wherein a flow cross section for the liquid at the small cross section area is smaller than at the inlet opening, further comprising a gas inlet provided at an outside of the housing and at least one gas outlet provided in the housing on a surface of the blade unit, the at least one gas outlet being connected to the gas inlet by means of a channel, and to a method for producing such an apparatus and an use of such an apparatus.

Claims

1-12. (canceled)

13. An apparatus for dissolving gas into a liquid, comprising a housing with an inlet opening for the liquid and an outlet opening for the liquid, and a blade unit arranged inside the housing in a small cross section area between the inlet opening and the outlet opening, wherein a flow cross section for the liquid at the small cross section area is smaller than at the inlet opening, further comprising a gas inlet provided at an outside of the housing and at least one gas outlet provided in the housing on a surface of the blade unit, the at least one gas outlet being connected to the gas inlet by means of a channel.

14. The apparatus according to claim 13, the blade unit including a jet nozzle and at least one connection element, connecting the jet nozzle with an inner wall of the housing.

15. The apparatus according to claim 14, wherein the at least one connection element has a cross section in the form of a blade.

16. The apparatus according to claim 14, wherein the at least one gas outlet is provided at a surface of the jet nozzle and/or on a surface of the at least one connection element.

17. The apparatus according to claim 13, wherein the at least one gas outlet is provided by at least one opening on the respective surface and/or by the respective surface being a porous surface.

18. The apparatus according to claim 13, wherein the at least one gas outlet is provided in the form of a lip, the lip in particular stretching across parts of or an entire length of one blade geometry.

19. The apparatus according to claim 13, the channel being provided in the blade unit.

20. The apparatus according to claim 13, being made as a one-piece apparatus, preferably by means of 3D-printing.

21. A method for producing an apparatus for dissolving gas into a liquid, preferably an apparatus according to claim 13, by providing a housing with an inlet opening for the liquid and an outlet opening for the liquid, including arranging a blade unit inside the housing in the small cross section area, wherein a flow cross section of the housing is made smaller at the small cross section area between the inlet opening and the outlet opening than at the inlet opening, and providing a gas inlet at an outside of the housing and at least one gas outlet in the housing on a surface of the blade unit, connecting the at least one gas outlet to the gas inlet by a channel.

22. The method according to claim 21, providing the apparatus by means of 3D-printing.

23. The method according to claim 21, making the apparatus as a one-piece apparatus.

24. Use of an apparatus according to claim 13 for dissolving gas into a liquid, wherein the liquid is guided through the housing, entering at the inlet opening and exiting at the outlet opening, and wherein the gas is provided at the gas inlet.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 schematically shows an apparatus according to the invention in a preferred embodiment.

[0028] FIG. 2 schematically shows a part of the apparatus of FIG. 1 in a more detailed view.

[0029] FIG. 3 schematically shows the apparatus of FIG. 1 in another view.

[0030] FIG. 4 schematically shows a use of an apparatus according to the invention in a preferred embodiment.

DETAILED DESCRIPTION OF THE DRAWINGS

[0031] In FIG. 1, an apparatus 100 for dissolving gas into a liquid according to the invention in a preferred embodiment is shown in a cross sectional view. Apparatus 100 comprises a housing 110 in the form of a tube with an inlet opening 111 for a liquid a like water and an outlet opening 112 for liquid a. At both ends of the tube, a respective flange 115 or 116 can be provided in order to allow appropriate mount in-line of a liquid conduit or the like. Of course, other ways of mounting like welding to pipes without flanges are possible.

[0032] Inside the tube 110, a blade unit 130 is arranged, the blade unit 130 comprising a jet nozzle 131, having a central hole, and four connection elements 132, having a cross section in the form of a blade. While this specific cross section can hardly be seen for the connection elements 132 (only two of them are visible in FIG. 1), the cross section of the walls of the jet nozzle 131 can clearly be identified as blade shaped. The jet nozzle is centrally place in the tube 110 with respect to a radial direction, i.e., centrally on the rotation axis 118 of the tube 110.

[0033] The wall or inner wall 117 of the tube 110 is shaped such that the inner diameter or cross section is smaller or narrow at the small cross section area 120, in which the blade unit 130 is arranged, than at the inlet opening 111 and at the outlet opening 112. Just by example, references d1 and the inlet opening 111 and d2 at the small cross section area 120 are shown in order to demonstrate the different cross sectional areas, in particular for the flow of liquid a.

[0034] Please note that the shown shape of the inner wall 117, including a conical shape between the small cross section area 120 and the outlet opening 116 and a rounded shape between the inlet opening 111 and the small cross section area 120 helps to improve the “Venturi”-effect and to guide the liquid in an optimal way. Nevertheless, the shape of the inner wall 117 could omit the conical and/or rounded shape, i.e., the tube could be of plain hollow cylindrical shape. As mentioned earlier, the blade unit 130 itself contributes to reducing the flow cross section.

[0035] It is to be noted that the flow cross section for liquid a in the small cross section area 120—or, in general, at the area or position with the narrowest cross section—is not only defined by the diameter of the inner wall 117 but is also influence by the cross section of the blade unit 130.

[0036] Further, a channel or channels 140 are provided inside the blade unit 130, i.e., inside the jet nozzle 131 and inside the connection elements 132, providing a connection between a gas inlet 141 provided at the outside of the tube 110 and several gas outlets 142 provide at the blade unit 130. For a more detailed view of the gas outlets 142 please refer to FIG. 2. Gas b, which shall be dissolved in the liquid a, can be introduced into the apparatus 100 via gas inlet 141. Gas b, which, e.g., can be oxygen, can then be guided through channel 140 to the gas outlets 142 and then be introduced or dissolved into liquid a.

[0037] As mentioned before, the special geometry of the apparatus with the reduced flow cross section for liquid a, a low static pressure is generated at the surface of the blade unit and, in particular, at the position of the gas outlets 142, and thus, gas b is drawn into the liquid a.

[0038] In FIG. 2, a cross section of connection element 132 as a part of the apparatus 100 of FIG. 1 is shown in a more detailed view. Inside the connection element 132 the channel 140 is provided, which is connected to, e.g., two gas outlets 142.

[0039] Due to the liquid a flowing along the curved surfaces of the connection element 132—which has the shape of a blade—underpressure or low static pressure of the liquid a is generated at the surface of the connection element 132 and, in particular, at the positions of the gas outlets 142. By means of the underpressure, gas b is drawn out of the gas outlets 142 and into the liquid a, such that it is dissolved in the liquid a.

[0040] The gas outlets 142 are preferably design with a lip or in a lip design such that the eventual outlet for the gas b is arranged averted to the flow direction of the liquid a. The lip in particular stretches across parts of or an entire length of one blade geometry. This helps to improve dissolving the gas b into the liquid a, in addition to prevent any potential clogging issues of the gas outlet openings or the respective channels.

[0041] Please also note that the orientation of the connection element 132 or its cross section as shown in FIG. 2 is slightly inclined with respect to the flow direction of liquid a. This can be achieved, for example, by designing the blade shaped connection elements with a slight rotation around axis 118 of FIG. 1.

[0042] Further, it is to be noted that the cross section shown in FIG. 2 as an example for connection element 132 can also apply to the cross section of the jet nozzle 131 shown in FIG. 1.

[0043] In FIG. 3, the apparatus 100 of FIG. 1 is shown in a top view, seen from the inlet opening 111 of FIG. 1 along the axis 118. In this view, four connection elements 131 connecting jet nozzle 132 to the tube 110 or its inner wall are shown.

[0044] In FIG. 4, the use of an apparatus 100 according to the invention in a preferred embodiment is shown. A liquid a, for example water, can be supplied from a tank 200 (or an open header tank) and shall be provided to another tank 210 (can also be an open header tank) via a conduit 205. In order to dissolve a gas b, for example oxygen, in the water a before being filled into or supplied to tank 210, apparatus 100 as, e.g., shown in FIGS. 1 to 3 can be used.

[0045] Apparatus 100 is mounted in-line with the conduit 205 and the oxygen b is supplied from a gas storage and/or dosing system 220 via a pipe 225 to the gas inlet (not shown in FIG. 4) of the apparatus 100. In this way, the oxygen can very efficiently be dissolved into the water a before filled into tank 210 as described before.

[0046] Preferably, the apparatus 100 can be used with a system shown and described in EP 2 008 513 B1. In particular, the apparatus 100 can be mounted upstream the muff coupling shown in FIG. 2 of EP 2 008 513 B1, at the position of the water inlet pipe. Thus, the tank shown in FIG. 2 of EP 2 008 513 B1 would replace or be used as the tank 210 shown in FIG. 3 of this application.

[0047] Also, the apparatus 100 can be used with a system shown and described in U.S. Pat. No. 8,556,236 B2. In particular, the apparatus 100 can be integrated between pipes 4 and 7 shown in FIG. 1 of U.S. Pat. No. 8,556,236 B2, replacing the gas dissolving unit 2.

[0048] The apparatus described in various embodiments herein will allow for in-line dissolving of gas into liquid for large liquid flow at low energy usage and it will result in very low pressure drop with almost no significant increase over a certain flow range due to the jet design (centre nozzle) for pressure recovery. Further, it will eliminate the need for any additional pump installations as it can be mounted in-line with the main liquid flow (see, e.g., FIG. 4) operating only on the energy provided from the main flow

[0049] Further, such apparatus can eliminate the need for external installations requiring space or other specific infrastructure for dissolving the selected gas into a liquid flow. It is scalable to fit with any liquid flow desired, e.g., from 20 to 30 000 m.sup.3/hour and it can be mounted in-line the main pipe and water or liquid flow using flanges or any other jointing system.

[0050] Also, the apparatus provides the possibility to increase gas saturation in any liquid inside a closed piping system regardless of the pipe size and it creates a faster dissolving/higher dissolving efficiency of gas into a liquid due to shorter transport distances from gas injection (the gas inlet) to the middle of the flow volume at the point of injection.

[0051] An increased gas to liquid dissolving efficiency can arise due to better mixing after the blade as a result of a slight turning current (depending on blade angle compared to flow direction as shown in and described with respect to FIG. 3). Further, it allows for an efficient dissolving of the gas into a large water flow by introducing micro bubbles of gas across the fin or trailing edge of a blade in combination with a restriction passage (due to the “Venturi”-effect) at very low energy demand (operational pressure loss is typically between 0.01 and 0.05 bar) The apparatus can be designed from non-corrosive materials, e.g., plastic that eliminates or reduces maintenance costs and increases lifetime. It can preferably be produced by 3D-printing as a complete unit or as sections or separate components to reduce production cost. In particular, 3D-printing allows for a structural design where gas channels feeding the pores or gas outlet openings at the blade can be integrated into the unit as it is being produced. This eliminates the need for any production of sub components that would need to be further machined and then mounted together to make up a complete unit or apparatus.

[0052] Further, the apparatus can be produced without a specific outer tube for in-line mounting into a larger construction, e.g., into a fish tank water distribution device for aquaculture in that an existing pipe or tube of a conduit is used as the tube of the apparatus described herein before.