Patent Application
20160317989
The present invention relates to systems for aerating or mixing a body of water and, in particular, it concerns a device, system and method for aerating or mixing a body of water employing a hydraulic motor.
It is known to employ mechanical aerators for increasing dissolved oxygen in bodies of water for applications such as fish ponds and water treatment. A typical mechanical aerator design employs a paddle wheel partially immersed in the water that is rotated by an electric motor so as to disrupt the surface of the water and constantly splash amounts of water into a spray cloud with significant surface area, allowing absorption of oxygen from the air and thereby increase the dissolved oxygen in the body of water. Other similar devices are used to mix and circulate water within pools.
The use of electrical appliances in a wet environment poses a significant safety risk, and electrocution has become one of the principle occupational hazards of workers involved in managing fish farms and water treatment facilities.
The present invention is an aerator or mixing device, system and method.
According to the teachings of an embodiment of the present invention there is provided, a device for aerating or mixing a body of water, the device comprising: (a) a mechanical displacer movable so as to displace water of the body of water, thereby aerating or mixing the body of water, and (b) a hydraulic motor have an inlet for receiving a flow of liquid the hydraulic motor being connected in driving relation to the mechanical displacer such that a flow of liquid supplied to the inlet is effective to move the mechanical displacer so as to displace water of the body of water.
According to a further feature of an embodiment of the present invention, the mechanical displacer is an aerator comprising a rotating wheel.
According to a further feature of an embodiment of the present invention, the mechanical aerator comprises a paddle wheel supporting a plurality of outwardly-projecting paddles.
According to a further feature of an embodiment of the present invention, the mechanical displacer and the hydraulic motor are mounted on a buoyant platform comprising at least one float, the buoyant platform being configured to maintain the mechanical displacer in a partially-immersed of fully-immersed state.
According to a further feature of an embodiment of the present invention, the hydraulic motor is a rotary motor.
According to a further feature of an embodiment of the present invention, the rotary motor has a rotating output. shaft linked so as to rotate at least part of the mechanical displacer.
According to a further feature of an embodiment of the present invention, at least part of the mechanical displacer is integrated with a casing of the rotary motor, and wherein the rotary motor is configured to drive rotation of the casing relative to a fixed axis.
According to a further feature of an embodiment of the present invention, the hydraulic motor is a positive-displacement motor.
According to a further feature of an embodiment of the present invention, the hydraulic motor has an outlet deployed to release the flow of liquid, and wherein the outlet is deployed such that, when the hydraulic motor is driven by a flow of water, the water is released via the outlet into the body of water.
According to a further feature of an embodiment of the present invention, the device has no externally-powered electric component.
There is also provided according to the teachings of an embodiment of the present invention, a system for aerating a body of water, the system comprising: (a) the aforementioned device deployed at least partially immersed in the body of water; (b) a water pump deployed remotely relative to the body of water; and (c) a length of tubing connected to an outlet of the water pump and to the inlet of the hydraulic motor so as to deliver a flow of water from the water pump to the hydraulic motor, thereby driving the mechanical displacer.
According to a further feature of an embodiment of the present invention, there is also provided a conduit deployed for drawing water from the body of water to an inlet of the water pump such that the hydraulic motor is driven by a flow of water drawn from the body of water.
According to a further feature of an embodiment of the present invention, the water pump is connected via additional lengths of tubing for driving a plurality of devices deployed in a plurality of bodies of water.
There is also provided according to the teachings of an embodiment of the present invention, a method for aerating or mixing a body of water comprising the steps of (a) deploying the aforementioned device at least partially immersed in the body of water; and (b) supplying to the hydraulic motor a flow of water so as to actuate the hydraulic motor, thereby moving the mechanical displacer so as to displace water of the body of water, thereby aerating or mixing the body of water.
The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:
The present invention is a device for aerating or mixing a body of water, and a corresponding system and method.
The principles and operation of devices according to the present invention may he better understood with reference to the drawings and the accompanying description.
Referring now to the drawings,
In general terms, device 12 includes a mechanical displacer (aerator) 14 movable so as to displace water of the body of water, and a hydraulic motor 16 connected in driving relation to mechanical aerator 14 such that a flow of liquid supplied to an inlet 18 of hydraulic motor 16 is effective to move mechanical aerator 14 so as to disrupt a surface of the body of water, thereby increasing a dissolved oxygen content of the body of water.
On a system level, as illustrated in
In certain preferred embodiments where water is used as the hydraulic fluid, a conduit 24 may advantageously be deployed for drawing water, preferably via a filter 26, from body of water 100 to an inlet of water pump 20 such that hydraulic motor 16 is driven by a flow of water drawn from the body of water. Alternatively, water may be drawn from another source. Where a mains water supply is available, the power to drive the aerator may optionally be derived from the pressurized water supply such that the function of the “pump” of the system may be performed by the pumping system of the water utility. In certain embodiments (not shown), a closed-loop hydraulic circuit may be used, with spent fluid from an outlet of the hydraulic motor being piped back to pump 20, directly or via a dedicated reservoir.
At this stage, it will be appreciated that various implementations of the present invention make a considerable contribution to the safety of aerator systems. Specifically, by employing hydraulic power to drive aerator devices 12, the hazards resulting from use of electrical equipment in a wet environment are essentially circumvented. The pump, which may be electrically powered, is located remotely from the body of water, such that this also does not pose a wet-environment shock hazard.
It should be noted that the phrase “hydraulic motor” is used herein in the description and claims to refers generically to any and all motors and actuators that are driven by a flow of fluid, and most preferably by a flow of liquid. Hydraulic motors according to this definition can be broadly subdivided into two classes, referred to herein as “positive displacement motors” and “momentum transfer motors.” In this context, a “positive displacement motor” may be defined as a motor which, if blocked from motion, will also substantially block the liquid flow. In positive displacement motors, torque is obtained from static pressure of the driving fluid. Examples of positive displacement motors include, but are not limited to, vane motors, gear motors, gerotor motors and piston motors. A “momentum transfer motor” is a motor in which motion/torque is generated by transfer of momentum from a stream of fluid impinging on surfaces of the motor (“dynamic pressure”). Examples of momentum transfer motors include, but are not limited to, various types of turbine devices. All of the above types of hydraulic motor are believed to be feasible for implementing the present invention. For certain preferred embodiments, positive displacement motors are believed to he advantageous. One particularly preferred option illustrated below is the use of a piston motor.
The hydraulic fluid employed to power the hydraulic motor of the present invention may be any fluid, but is most preferably a liquid. An option of using a closed hydraulic system (with or without a reservoir/buffer) falls within the scope of the invention, and could be implemented using oil-based hydraulics. However, particular economy and simplicity of implementation may he achieved by using water as the hydraulic fluid. This allows drainage from an outlet of the hydraulic motor directly into the body of water, without requiring a return flow tube connected to the motor outlet. In this context, it should be noted that the term “water” is used to refer generically to clean or contaminated (waste) water, seawater and other water-based solutions. In some eases, the water used to drive the hydraulic motor may contain certain additives such as, for example, a water treatment or conditioning chemical, or a medication needed for treatment of fish. These additives are then released into the body of water from the outlet of the hydraulic motor.
The term “remote” is used to refer to positioning of pump 20 at a location out of contact with the water, and at a sufficient spacing from the body of water that it is not considered to pose a wet-environment shock hazard. The required distance depends upon the circumstances, but a distance of a few meters is typically sufficient, and with other suitable safety precautions, even smaller distances may be considered sufficient, as is known in the art.
In certain applications, such as intensive fish farming, where the farming system typically includes a forced-flow pump for circulating water within each pool, pump 20 may in fact be the standard water circulating pump of the farming system. In this case, a branch pipe is typically added to route an appropriate quantity of pressurized water to aerator device 12 while the remainder of the flow returns to the pool via the primary circulation channels.
A single pump 20 may be used to supply a flow of water via additional lengths of tubing 22′, 22″ for driving additional aerator devices 12′, 12″ deployed in a plurality of bodies of water 100′, 100″. Similarly, for larger pools, two or more aerator devices 12 may he deployed for aerating a single pool (not shown).
The present invention may be used to advantage in a wide range of applications in which aeration and/or circulation/mixing of a body of water, any other liquid, is required. Primary examples include extensive fish farming, intensive fish farming, other types of aquaculture, and various types of treatment of waste water or sewage. The invention may also be applied to advantage in the chemical industry a id the food industry.
Turning now to a first ion-limiting exemplary embodiment of aerator device 12, this is shown in
For effective operation, the mechanical aerator should typically be maintained in a predefined partially-immersed state. For example, in the case of a paddle wheel aerator, the paddles should typically be immersed when in their lowest position but should be clear of the water during the majority of their motion. This typically corresponds to immersion to a depth of between about 20% and about 40% of the outer diameter of the paddle wheel. In order to maintain the desired degree of immersion, mechanical aerator 14 and hydraulic motor 16 are preferably mounted on a buoyant platform comprising at least one float 32. In the non-limiting example illustrated here, the buoyant platform includes a frame 34 configured for receiving a pair of floats 32, and with features (including a clamping band 36) for supporting hydraulic motor 16 and mechanical aerator 14, thereby defining the desired extent of partial-immersion.
For a rotary mechanical aerator 14, hydraulic motor 16 is advantageously implemented as a rotary motor. As mentioned above, many different types of hydraulic motor may be used to implement the present invention. In this case, a particularly simple implementation may employ direct connection of a rotating output shaft 38 of the motor to the mechanical aerator, although connection through a step-up or step-down transmission may clearly also be used if needed.
Certain particularly preferred implementation of the present invention employ a positive-displacement motor. One particularly preferred example illustrated here is a piston motor. Water-powered piston motors are known in the art, and may be implemented by way of example according to the teachings of U.S. Pat. No. 7,258,057 which is hereby incorporated by reference in its entirety as if fully set out herein. In particular,
Further details of a preferred implementation of the connecting-rod assemblies, and the associated valve structures may be found in the description of the aforementioned U.S. Pat. No. 7258,057. Motors implemented according to similar designs are commercially available in products such as automatic garden hose reels (e.g., AQUAWINDER™ auto rewind hose reel commercially available from Suncast Corp., USA) and pool cover rolling mechanisms (e.g., AQUALIFE HYDRO™ automatic pool cover commercially available from Maytronics, France).
In order to achieve the safety advantages offered by the present invention, particularly preferred implementations of aerator device 12 are implemented without any externally-powered electric component. In simple implementations, the operation of the aerator device is purely hydro-mechanical, operating whenever it receives pressurized water flow to its inlet, without any electrical components. In certain cases, it may be desired to incorporate various electrical components, such as sensors for monitoring, properties of the body of water, and/or control components such as valves for controlling operation of the aerator device. In such cases, all electrical components are preferably low-power components operated by power from a local battery pack, which may optionally be a rechargeable battery pack charged by solar cells and/or by a small hydro-electric generator associated with hydraulic motor 14. In all such cases, the absence of externally-supplied electrical power connection to an electrical power grid) renders any risk of electrocution negligible.
Turning now to
This structure may be best understood with reference to the cut-away view of
The integration of the mechanical aerator function with an inverted for of the hydraulic motor provides a particularly compact device which may offer advantages in various applications. In all other respects, the structure and function of the device of
Although described thus far with reference to one preferred application in the field of aerators for pools, it is noted that similar principles are applicable to any and all motor-driven devices which are to he used at least partially immersed in a body of water. A second group of applications of particular relevance is devices for mixing and circulating water within a pool.
By way of a first example.
Turning finally to
It will be appreciated that the above descriptions are intended only to serve as examples, and that many other embodiments are possible within the scope of the present invention as defined in the appended claims.
