Patent Application
20050253288
The present invention relates to the treatment of liquids, including waste liquids. In particular, the present invention relates to an apparatus for mixing or aerating liquids.
Aeration devices used in the treatment of liquid, especially water, are known in the prior art. The aeration devices may be employed to encourage aerobic bacteria in treating wastewater or in treating bodies of water to make the water more potable or more suitable for food production. In addition, the aeration devices are commonly used for ice control purposes.
One type of aeration device known in the art includes a motor located above the liquid being treated and generally mounted to a support structure. A leg extends from the motor below the liquid surface and connects the motor to a submerged propeller. The leg includes a shaft coupled to the motor which drives the propeller and may include an outer housing that surrounds the shaft. An air inlet provided above the liquid surface allows the rotating propeller to draw air into the leg and supply a flow of air to the propeller. For this type of aeration, the quantity of air discharged into the liquid is dependent solely upon air flow created by the rotating propeller.
Airflow-assisted aerators, which augment the air flow created by the propeller, are known in the art. These aerators, however, do not include a blower and a propeller capable of being operated at different speeds while being powered by the same aerator motor, which results in sub-optimal aerator efficiency.
The present invention is an improved aerator that allows for the efficient supply of additional aeration capacity.
The present invention is an aerator for inducing air flow below the surface of a liquid. The aerator includes a motor having a drive shaft. A propeller is operably connected to the drive shaft of the motor and a blower is operably connected to the motor. The aerator further includes an air flow path that has an inlet and an outlet, with the inlet connected to the blower and the outlet located near the propeller. The blower and the propeller rotate at different speeds.
While the above-identified drawing figures set forth several embodiments of the invention, other embodiments are also contemplated, as noted in the discussion. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art which fall within the scope and spirit of the principles of the invention. The figures may not be drawn to scale. Like reference numbers have been used throughout the figures to denote like parts.
Blower 14 has a blower intake 25 and is connected to a discharge pipe 26 that extends from blower 14 to pipe saddle 22, which is positioned over draft tube 24. Discharge pipe 26 and draft tube 24 define a flow path so that, when blower 14 is engaged, air is drawn into blower 14 through blower intake 25 and delivered to a hub (not shown) in propeller 16 that defines an airflow outlet for ejecting the air into the liquid. Blower 14 may provide air pressure and air flow well in excess of the amount of air of a traditional aspirating aerator, thereby enabling aerator 10 to force large volumes of air into the liquid. Blower 14 may be any suitable type of air supply means known in the art.
Draft tube 24, discharge pipe 26, and the hub in propeller 16 are preferably sized and shaped to maximize air flow. As shown in
In some applications it may be desirable to introduce a gas other than air into the liquid to be treated. As such, the term “aeration,” as used herein, is intended to encompass the introduction of any gas or combination of gasses, including air.
Discharge pipe 26 may include a throttling valve 28, an air discharge pressure gage 30, and air discharge pressure switches 32 (a high pressure discharge switch and a low pressure discharge switch) to regulate air flow from blower 14 to the air outlet of propeller 16. The inclusion of throttling valve 28 maximizes aerator performance and allows for adjustment of the airflow and the mixing and aeration ratio. Throttling valve 28 also allows air flow from blower 14 to propeller 16 so that propeller 16 can be used to mix the liquid without introducing air into the liquid from blower 14.
In some embodiments, a clutch (not shown) may be used to operably connect motor 12 and blower 14. When the clutch is engaged, motor 12 rotates both blower 14 and propeller 16. However, when the clutch is disengaged, motor 12 rotates propeller 16 without rotating blower 14, thereby allowing propeller 16 to mix the liquid without introducing air into the liquid from blower 14. The clutch may be included in aerator 10 along with throttle valve 28, or the clutch may be included alone. Any type of clutch known in the art may be used.
As shown in
As shown in
Propeller shaft 50 extends through a bearing support tube 56 which mounts to motor mount 20. An upper bearing 58 and a lower bearing 60 are housed within bearing support tube 56 and align propeller shaft 50 to take up thrust loads from propeller 16. Upper bearing 58 supports propeller shaft 50 near upper end 52 and lower bearing 60 supports propeller shaft 50 near lower end 54 to provide maximum stability to propeller shaft 58. In alternate embodiments, the bearings may be located along propeller shaft 50 in any multiplicity and at any location.
Upper bearing 58 includes a bearing cone 62 and a bearing cup 64, which are flanked by a lug nut 66 and a seal 68. An upper seal 70 abutting lug nut 66 protects upper bearing 58 from liquid penetration due to splashing, submergence, or any other action that may cause foreign liquid to enter bearing 58. Upper end seal 70 includes a pair of O-ring seals 72, a seal module 74, and a pair of seals 76. A retaining ring 78 helps retain upper seal 70 and upper bearing 58 on end 52 of propeller shaft 50.
Similarly, lower bearing 60 includes a bearing cup 80 and a bearing cone 82, which are flanked by a seal 84 and an external retaining ring 86. As shown in
As shown in
Propeller 16 has a hole to receive lower end 54 of propeller shaft 50. Propeller 16 is retained on propeller shaft 50 by a lug nut 106 and a set screw 108 (shown in
In one embodiment, at least a portion of propeller 16 fits inside draft tube 24 so that under normal operating conditions, when propeller 16 is submerged beneath the surface of a liquid, a hydrodynamic seal is formed between propeller 16 and draft tube 24. This seal causes air from blower 14 to exit through the hub formed in propeller 16 and not through any space existing between propeller 16 and draft tube 24. In other embodiments, air may exit through both propeller 16 itself and the space existing between propeller 16 and draft tube 24, or the air may exit through the space alone.
A splash guard cone 110 is provided on the propeller side of lower end seal 60 to protect lower end seal 60 against foreign materials and liquids. Splash guard cone 110 may be fabricated from stainless steel or any other suitable material. A retaining ring 112, a splash guard cone 114, and a wave spring 116 are associated with splash guard cone 110.
When motor 12 of the present invention is engaged, blower 14 and propeller 16 turn simultaneously. Transmission 18 enables blower 14 and propeller 16 to operate at different speeds. The ability to operate blower 14 and propeller 16 at different speeds is a key feature of the present invention because it allows blower 14 and propeller 16 to operate more efficiently and provides better mixing of the liquid and/or the air. In some embodiments of the present invention, transmission 18 is geared so that blower 14 rotates at a speed of rotation (measured in rotations per minute, “rpm”) that is at least about twice as great as the speed of rotation of propeller 16. In other embodiments, transmission 18 is geared so that blower 14 rotates at a speed of rotation that is at least about three times as great as the speed of rotation of propeller 16. Particularly suitable rotation speeds for propeller range 16 from about 400 rpm to about 1,000 rpm, while particularly suitable rotation speeds for blower 14 range from greater than about 3,600 rpm.
For transmission 18 to enable blower 14 and propeller 16 to operate at different speeds, it must be geared to either increase the rate of rotation of propeller 16 or blower 14 relative to the motor speed or decrease the rate of rotation of propeller 16 or blower 14 relative to the motor speed. As shown in
Transmission 18 may also be connected to the drive shaft of motor 12 closest to blower 14 (i.e. drive shaft 42). In such a configuration (not shown), motor 12 may be operated at a lower rpm and transmission 18 may be used to accelerate the rotation speed of blower 14. Thus, for example, if transmission 18 in this alternate embodiment has a gear ratio of 1:4 and motor 12 operates at 900 rpm, propeller 16 and blower 14 have rotation speeds of 900 rpm 3,600 rpm, respectively.
Mounting hinges 132 (one shown in
In one embodiment, motor mount 20 is designed to allow for removal of motor 12 or an aerator section for service without dismantling the entire aerator from the mounting system.
Any type of support system known in the art may be used to support the aerator of the present invention, including non-flotation type support systems. For example, the aerator may be coupled to a stationary structure such as a wall or other stationary member. In addition, any attachment means known in the art may be used to attach the aerator to the support system, including any means for pivoting the aerator from a horizontal position so the propeller is submerged beneath a liquid surface.
As described above, the aerator of the present invention enables a blower and a propellor to be powered by the same motor. The blower provides an increased ability to supply air to the propeller and aerate liquid. A transmission is included in the aerator so the blower and the propellor can operate at different speeds to provide increased operational efficiency. An air flow valve is included in the aerator so air flow from the blower to the propeller can be regulated and even shut off. As such, the aerator of the present invention may be used both as an aerator or as a mixer.
Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.
