WO2012000053A1

WO2012000053A1 - An apparatus to circulate liquid and induce a gas

Info

Publication number: WO2012000053A1
Application number: PCT/AU2011/000825
Authority: WO
Inventors: Anthony John Dickson
Original assignee: Waterfresh Pty Ltd
Priority date: 2010-07-01
Filing date: 2011-07-01
Publication date: 2012-01-05

Abstract

An apparatus is designed to mix a gas with a liquid body and circulate the liquid body. The apparatus can operate in either an open liquid body or in a closed medium. In an open liquid body the apparatus has floats to support the apparatus and in a closed liquid body system has a mounting. The apparatus draws air or a gas from above the liquid level and disperses the gas as fine bubbles below the surface through a diffuser pump.

Description

AN APPARATUS TO CIRCULATE LIQUID AND INDUCE A GAS

Field of the Invention

The invention relates to floating circulation pumps.

Background of the Invention

Circulation pumps are used in a body of liquid to promote absorption of gas by the recirculatory movement of a liquid from a lower level to a level near the surface where a gas is contacted and carried by the moving liquid toward the lower liquid level. Circulation pumps may float (or not) and are used in open liquid body systems (aeration of ecosystems such as ponds, rivers, sewage systems and water based food farms) and in closed liquid body systems (contact chambers for gasses and liquids).

To sustain a healthy ecosystem in a body of water such as ponds, rivers, organic life and also sewage systems, oxygen is required for aerobic bacteria to survive.

In general oxygen enters these water bodies through contact with a surface and the atmosphere. In cases where the water has little movement or circulation only the surface layers of water have access to the oxygen and the aerobic bacteria that reside near the bottom or where there is organic matter die off.

The prior art in aeration and circulating systems reveals mechanical systems that:

• pump water from the surface and spray the water into the air.

• pump gas through tubes and small orifices at the lower liquid levels.

• circulate water to come in contact with the surface to increase aeration

• induce air by pumping water from the surface with a marine impeller and pushing air down towards the lower levels.

Typical prior art devices are found e.g. in Patents US 4179243, US 4030859, US 2827268, US5021154 and GB1559 868.

One of the most efficient way of combining a gas with a liquid is to increase the surface area of the gas relative to the body of water. This is done by converting the volume of gas into very small bubbles that remain in the liquid for as long as possible. A good example is champagne bubbles slowly rising in a glass. Gas contact chambers are sealed tanks that a water body is pumped through or recirculated in while a gas is injected at the lower level through diffusers to form small bubbles that float to the surface where they remain.

Description

It is an object of the invention to provide a device that draws a liquid from a lower level in a water body, to a higher level where a gas is introduced. An impeller draws liquid from the lower level and gas from above the liquid surface and entrains the gas with the liquid.

Brief Description of the Drawing Figures

In order that the invention be better understood, reference is now made to the following drawing figures in which:

Figure i is a cross-section drawing of a floating embodiment of the invention;

Figure 2A is a cross-section drawing of the motor shaft, impeller,

diffuser, diffuser support and gas inlets;

Figure 2B is a cross section through some of the mechanical components of the pumping apparatus showing the detail from which

Figure 2a is taken;

Figure 3 A is a perspective drawing of the diffuser pump;

Figure 3B is a cross section of the diffuser shown in Figure 3A;

Figure 3C is a detail taken from Figure 3B;

Figure 4A is an exploded perspective of the diffuser pump showing the diffuser vanes and the vortices inducers;

Figure 4B is another exploded perspective of the diffuser pump;

Figure 5 is a schematic drawing showing the general flow patterns for the liquid and gas produced by the invention in an open liquid body;

Figure 6A is a schematic drawing showing open suction end;

Figure 6B is a top plan view of the schematic depicted in Figure 6A; Figure yA is a schematic drawing showing the preferred anchor system; Figure 8 is a cross-section drawing of the enclosed liquid body and invention and the major components;

is a schematic drawing of the general flow patterns for the liquid and gas produced in a closed liquid body; and

is a side elevation of a rotor in accordance with the teachings of the present invention;

is a plan view of the rotor depicted in Figure io;

is a cross section through a rotor and stator in accordance with the teachings of the present invention;

is a perspective view of a rotor illustrating a second

embodiment of the air side vanes;

is a cross sectional view of a further embodiment of the invention;

is a top cross sectional view of a manifold;

is a cross sectional detail depicting the impeller of Figure 14; is a side elevation of the device depicted in Figures 14-15, in operation;

is a side elevation of yet another embodiment of the invention; and

is a cross section of a liquid tank incorporating the teachings of the present invention .

Best Mode and Other Embodiments of the Invention

Referring to the drawing Figure 1, a floating pump apparatus is made up of a buoyant float assembly 23 that supports the other components, suspending them from the water line 25. This particular example of a float support has two float portions 23 that are joined together by a rigid bridge 24.

The apparatus is powered by an electric motor 1 that is central to the floats 23 and is fixed to the bridge 24. The electric motor 1 drives a diffuser pump having a centrifugal impeller 5 located below the surface of the water body. The distance from the surface will depend on the application however it will generally be between 300 and 1500 millimetres. The diffuser pump assembly 8 is suspended or supported by the pipe support 4. The motor 1 directly drives the pump impeller 12 below it via a motor coupling 2 and a shaft 3. When operating, liquid from the liquid body 26 is drawn through the slots 21 on the one or more inlet or suction pipes 20. The suction pipes are attached and supported centrally by the suction manifold head 7 and enclosed at their ends by caps 22. The suction head is supported by the descending suction support pipe 11 which delivers liquid to the diffuser pump 5. Depending on the size of the apparatus and application the suction head 7 can have multiple suction pipes 11, or no pipes and just an open or slotted suction head 7b refer to figure 6 or suction head 7a in figure 8.

In Figure 2 A the sectioned close up view of the diffuser pump shows the workings of the pump. Before operation the liquid has filled the pump assembly and is at the same level in the support pipe 4 as the liquid level 25. When the impeller 12 rotates at motor speed (between 2900rpm and 700rpm depending on size.) liquid is moved by the impeller vanes 13 and accelerated radially through the housing's lower stator 9 towards the stator diffuser vanes 10.

The energy imparted to the liquid by the impeller vanes, plus the centrifugal forces by rotation, and the diminishing section between the inner stator walls, greatly increase the exit velocity of the liquid to enable the liquid coming off the impeller face 15 to flow across the gap 17 and expand to make contact with the upper stator face 16. This causes a venturi effect resulting in a low-pressure zone in gap area 17. This is best illustrated in Figure 3A detail C. The top surface or section of the impeller has vanes 14 that act as a gas blower and initially pumps the static liquid out of the support pipe 4 and thereafter draws and pumps gas or air from the orifice 18 and/or tube 19 into the gap zone 17. The combination of the venturi effect and the assistance of the impeller fan increases the flow of gas into the chamber and therefore into the liquid.

Gas or air enters the support pipe 4 at either or both of the orifice 18 and the auxiliary gas intake tube 19. The auxiliary gas intake tube 19 is used if a particular gas is required to be introduced (from a separate supply) or combined with another gas.

The combination of the gas and liquid travel through the stator vortex inducing radial slots 10A that are fixed in a circular pattern on the perimeter of the stator or housing outlet. Figure 4 shows in an exploded view, the diffuser vanes 10 and vortex inducers 10A. The inducers preferably are located on the upper stator (or air) half and stepped back from the inner perimeter of the stator vanes 10.

The radial and circular flow velocities of the liquid as it passes through the vortex inducers 10a and the diffuser vanes 10 causes small vortices and high shear in the liquid and gas, resulting in small gas bubbles.

Breaking down the bubble size greatly increases the surface of area of the gas. This allows the liquid to gas ratio to greatly increase. Also the circulation flow patterns that develop in the liquid body carry the smallest bubbles further than larger bubbles toward the lower levels of the water body therefore ensuring a greater contact time with the liquid. Also the induced flow patterns caused by the flow of liquid and gas radial 14 from the diffuser pump 5 induce recirculation flows as shown in figure 5. These flow patterns 41 at the liquid surface also increase the ability for gas transfer into the liquid body from the liquid surface 25. The downward flow pattern 42 is the main flow from the diffuser pump 5 and this flow carries the small gas bubbles downward against the forces of buoyancy to the lower levels. The induced flows 43 circulate liquid below the diffuser pump 5 and continually circulate and hold the gas bubbles in this region.

Figure 6 shows the preferred fixing or anchoring system, it being

understood that there are alternative anchoring devices for the apparatus. A weight may be used as an anchor. The anchor device may be a pole 26 is located on or driven into a fixed point on the bottom of the pond or containment of the water body 29 and has a swivel 27 at the upper end. This swivel 27 is attached to a tether, being a wire or ridged tube that is attached to the float 23. The flow patterns developed will drive the apparatus in a circular motion 28 around the pole 26 therefore covering a large area of the water body, making the aeration of the water body more efficient in the use of power.

Overall the apparatus is efficient in the aeration or introduction of gasses to a liquid body. This is due to the combination of circulating the liquid from the lower levels to high levels and inducing and dispersing the gas o air below the surface as small bubbles, where they can be circulated and carried b the various flow regimes in the liquid body.

With reference to Figures 8 and 9 the apparatus can be installed in a closed container or closed liquid body system. The closed liquid body is generally represented by a vessel 34 to contain the liquid and a gas sealed section above the liquid level 25 marked as 35. The pumping apparatus includes for its mounting, a flange 33 that is fixed to a mating flange 33A incorporated in the top of the vessel 34·

The operation of the apparatus performs as described previously. However in a closed liquid body system gas is preferably the introduced into inlet tube 19 and flows through the support pipe 4 then enters the liquid as described previously through the diffuser pump 5. Gases that eventually flow to the surface are captured in the sealed section 35 then re-injected back to the liquid body by entering an orifice 18 in the support pipe. This continually recirculates the volume of gas 35 above the liquid level 25 to the contained liquid body. The suction head 7a in this sketch has slots and depending on the application could either be fitted with e.g. slotted suction heads 21 or a tapered suction inlet and outlet.

The liquid to be treated in a continuous flow arrangement would exit and enter continuously through inlet orifices 31 and 32. However batch or single treatment of the fixed liquid volume can also take place. A good example of a continuous process well suited for the apparatus is an ozone contact chamber.

As shown in Figure 10, the rotor or impeller has different kinds of vanes on each of its two faces, A first face or "water side" 100 has deep, curved vanes 101 that are adapted to accelerate water from the inlet to the outlet of the stator. As shown in Figures 10 and 11, these vanes c rve in plan view from a central part 102 of the rotor to a periphery 103 of the rotor. The height of the vanes also increases in a non-linear fashion from a lowest height at the periphery 103 to a maximum height 104 located between the periphery 103 and the central portion 202. From that intermediate highest point 104, the height of the vane decreases along a generally linear sloped portion 105 that is located between the high point 104 and the central portion 102. Note that the water side vanes terminate 106 close to but not at the true centre of the rotor.

As shown in Figure 12 the water side stator half 120 includes a curved throat 121 that blends the interior surface, smoothly, from the water side stator inlet 122 to the water side stator outlet or discharge 123. The shape of the water side rotor blades 101 conforms to the shape of the throat 120 while maintaining a practical gap therebetween. Figure 12 also illustrates that the radius of the throat 124 of the air side 125 of the stator is a smaller radius that the radius of the water side throat 121. Thus and as suggested by Figures 10 and 12, the overall height of the air side vanes 126 is lower than the height of the water side vanes 101. In general, the curvature of the air side vanes (in plan view) is less than the curva ture of the water side vanes 101. A second embodiment of the air side vanes arrangement is shown in Figure 13. In that Figure, the air side vanes 130 are straight in the radial direction and tapered in height from a minimum height 131 adjacent to the rotor perimeter 132 extending to a maximum height 133 located where the vanes 130 join with a preferably integral hub 134.

As better shown in Figure 12, it is preferred that the air side half of the stator include a flat ring shaped landing 140 that lies radially outward of the tip 141 of the rotor. This ring shaped landing 140 is provided with radially grooves 142 that are intended to induce vortices in the flow of mixed air and water as that mixture spirals out of the interior of the stator and before that flow exits the stator' s diffuser vanes 10 (if any). The vortex inducers 140 can be used without stator veins and the stator vanes 10 may be used without vortex inducers 140.

A further embodiment of the invention is depicted in Figures 14-16. As shown in the cross section of Figure 14, a floating diffuser pump apparatus 140 comprises a generally flat bottomed upper float compartment 141 and one or more auxiliary floats 142 located below the generally flat bottom 143 of the upper compartment 141. The size, shape and distribution of the auxiliary floats 142 can be tailored to the weight and construction of the entirety of the apparatus 140, for example to compensate for the weight or location of the electric (or other) motor 144. In preferred embodiments, the underside 143 of the upper compartment 141 is just below the nominal water level. This is so that the diffuser pumps impeller or rotor 145 can draw water from water's bottom and discharge it into the uppermost layers of the water column. In this embodiment, the impeller 145 is similar to the impellers depicted in other embodiments. It comprises a single impeller disk having an arrangement of vanes 140 on one side for drawing air and a second set of vanes 147 on an underside for drawing water. The air supply for the air vanes is from the interior of a vertical tube 148 that extends from the upper part of the pump housing 149 th ough to a location 150 preferably above the upper surface 151 of the upper float compartment. In preferred embodiments, the electric motor 144 is mounted above the air supply tube 148 and the motor shaft extends via a coupling and an intermediate shaft 151 to the rotor or impeller. The water is drawn into the pump housing from intake tubes 154 then through a manifold 153 whereupon the air water mixture is ejected out of the stator. In this example, the manifold 153 collects through an array of four equally spaced intake tubes 154. As shown in Figure 16, the intake tubes 154 extend from the manifold 153 close to the water surface 160 to one or more locations 154 close to the bottom surface 155 of the pond, reservoir or water body that is being served by the apparatus 140. The lower ends of the intake tubes 154 can be weighted to the bottom by weights or hollow water conditioners, for example, hollow water magnetic water conditioners 155.

Another embodiment of the invention is depicted in Figure 17. In this embodiment, the multi-tube manifold 153 is replaced by a single vertical or intake tube 170. A water collection fixture of head 171 is located preferably

circumferentially around the end of the intake tube 170. The water may optionally pass through a (cylindrical or other) water conditioner 172 prior to being delivered to the diffuser pump 173. In preferred embodiments, the suction inlet 171 is located close to or adjacent to the bottom surface 174 of the body of water. In this way, it can intake water with low oxygen content from close to the bottom 174.

The liquid that radially flows from the impeller produces a venturi affect or low pressure zone within the diffuser pump or impeller housing. This zone plus the addition of the fan draws air from the above surface of the liquid body and combines the gas with the liquid. This mixture of liquid and gas is then redirected through peripheral vanes and vortices inducers that break the air bubble size down to a size that greatly increase the surface area of the gas respective to the liquid body.

Also the radial flow of liquid that leaves the diffuser body that houses the impeller, induces flows of the liquid from the above and below the outside of the diffuser body to increase circulation of the water body. This circulation carries the small bubbles of gas to lower levels of the water body and secondly creates large liquid movement on the liquid body surface.

Figure 18 illustrates a contact chamber made in accordance with the teachings of the present invention. In this example, the gas contact chamber 180 is a closed tank 181 having an optional external suction or gas intake port 182. A device in accordance with the teachings of the present invention can be placed in the tank for the purpose of re-circulating, in the body of water, gas that resides above the liquid surface within the vessel. Gas above the liquid level in the tank 181 is drawn into ports 183 whereupon the gas is drawn into the diffuser housing 184 and distributed in a flow pattern indicated by the arrows 185. The external suction port 182 is used optionally when there is a requirement for a larger flow of gas. Also gases that are difficult to pump such as ozone can be introduced through the external suction port, as required. In this embodiment, flotation is not required because a hollow pipe 186 connects or suspends the diffuser or impeller mechanism 187 to the interior of the tank.

Gases in the recirculating water that are entrained but not dissolved eventually rise to the surface as small bubbles. The gases released by these bubbles enter the return holes 183 formed in the riser 186. If gas pressure accumulates within the tank, a breather 188 may be provided in the tank above the maximum water level.

In practice, a wide variety of rotor and stator arrangements may be used for the purpose of entraining a gas into a liquid that flows through a stator. However, it will be preferred when the water side vanes of the rotor and water side of half of the stator are optimised for pumping liquid and when the air side of the rotor and air side half of the stator are optimised for pumping a gas such as air.

Claims

What is claimed is:

1. A device for circulating a liquid, comprising: a diffuser pump having a housing in which is located an impeller disk;

the impeller disk having two sides;

one side having vanes for drawing a liquid into the housing, the other side having vanes for drawing a gas into the housing;

the housing having a vertical gas intake that extends from the housing to a source of gas and one or more liquid intakes that extend below the housing;

the diffused pump being driven by a motor having a vertical shaft that extends through the gas intake.

2. The device of claim l, wherein: the vertical gas intake acts to suspend the housing from a float body, the float body also supporting the motor above the housing.

3. The device of claim 1, wherein: the vertical gas intake acts to suspend the housing from the interior of a tank adapted to contain a liquid that is served by the device.

4. The device of either of claims 1-3, wherein: the housing further comprises a stator having a pattern of vortex inducing slots.

5. The device of either of claims 1-4, wherein: the housing further comprises a stator having a pattern of stator vanes.

6. The device of either of claim 1 or 2, further comprising: a tether for attaching the device to a fixed point.

7. The device of any one of claims 1-6, further comprising: an auxiliary gas intake tube that is adapted to carry a gas into the vertical gas intake.

8. The device of either of claims 1 or 2 or 6, wherein: the liquid intake further comprises an intake manifold and cooperating intake tubes that extend from the manifold.

9. The device of any one of claims 1-8, wherein: the liquid intake is associated with at least one water conditioner.

10. The device of claim 9, wherein: the conditioner is a magnetic water conditioner.