Title of Invention	"AN IMPROVED MECHANICAL FLOATING AERATOR FOR OXYGEN TRANSFER FOR BIOLOGICALTREATMENT OF WASTEWATER"
Abstract	An improved mechanical floating aerator for oxygen transfer for biological treatment of wastewater which comprises a float (1) made of non corrosive light weight material, the said Moat provided with a center hole, the said hole is conical in shape at the top phase of the said float , characterized in that a diffuser(2) having externally conical in shape so as to movably fixed inside the said center hole of the said float(l), a shaft(3) passing and concentrically fixed through the said diffuser(2), the said shaft(3) also passing through a bearing(7) and a impeller(4), the said impeller(4) is mounted on the said shaft(3) at the non driving end, at the driving end side the said shaft(3) passes through and supported by a pair of taper roller bearing(5), a grease feeder(9) is fixed and an oil seal (10) to said bearings(5), the said shaft(3) also coupled to a conventional prime mover(8) through a flanged coupling (6)

Title of Invention

"AN IMPROVED MECHANICAL FLOATING AERATOR FOR OXYGEN TRANSFER FOR BIOLOGICALTREATMENT OF WASTEWATER"

Abstract

An improved mechanical floating aerator for oxygen transfer for biological treatment of wastewater which comprises a float (1) made of non corrosive light weight material, the said Moat provided with a center hole, the said hole is conical in shape at the top phase of the said float , characterized in that a diffuser(2) having externally conical in shape so as to movably fixed inside the said center hole of the said float(l), a shaft(3) passing and concentrically fixed through the said diffuser(2), the said shaft(3) also passing through a bearing(7) and a impeller(4), the said impeller(4) is mounted on the said shaft(3) at the non driving end, at the driving end side the said shaft(3) passes through and supported by a pair of taper roller bearing(5), a grease feeder(9) is fixed and an oil seal (10) to said bearings(5), the said shaft(3) also coupled to a conventional prime mover(8) through a flanged coupling (6)

Full Text	This invention dates to an improved mechanical floating aerator for oxygen transfer for biological treatment of wastewater. The present invention relates to environmental engineering field and more particularly to be activated sludge process in aerobic treatment of domestic and industrial wastewater. Conventionally aerobic purification of biodegradable waste is carried out through (i) Fixed bridge mounted mechanical aerator (ii) Floating type low speed mechanical aerators and (iii) Floating type high speed mechanical aerators. The conventional fixed bridge mounted aerators are particularly useful when large treatment capacity is required. Fixed type aerators are bulky and require civil construction platform for mounting. Therefore, this is not useful from economical point of view. Floating type low speed aerators are quite bulky and require floats of large sizes to keep the aerator floating. Also their oxygen transfer capacity is less because of low R.P.M. Floating type high speed mechanical aerators presently in use is mainly of one type viz. high speed floating aerator. This type of floating aerator has been mainly used fot aerobic biological treatment of wastewater. It suffers from the uneven distribution ct load, more vibrations, motor bearing failure and bending of shaft together with problems of misalignment and deflection. Fig. 1 shown in the drawings accompanying this specification depicts the salient features of hither to known high speed floating aerator. It comprises of an impeller (1) made of bronze mounted at the non driving end on a shaft (2). Shaft (2) supported by Teflon bush (3) and at driving end of shaft a flanged coupling (4) is fixed and coupled with prime mover (H, the whole diffuse assembly (6) is mounted on a Fibre Reinforced Plastic (FRP) float body (7). When the prime mover (an electric motor) starts, it drives the shaft on which, at non driving end an impeller is mounted and this results in rotational motion of the impeller. This relational motion of impeller sucks wastewater from bottom and throw it out with turbulence/water droplets so as to come in contact with atmospheric air and thus oxygen transfer takes place for metabolic activities of microorganisms responsible for biodegradation and purification of wastewater. The rotation of impeller provides sufficient mixing and circulation of wastewater in the aeration tank. The above said floating aerator has inherent defect of deflection and bending of shaft, motor bearing failure and misalignment and therefore not suitable and efficient for the intended purpose. It suffers from the uneven distribution of load, more vibrations, motor bearing failure and bending of shaft together with problems of misalignment and deflection. The object of this invention is to provide an improved floating aerator for the biological treatment of liquid wastes avoiding the above referred drawbacks particularly of deflection and misalignment and preventing motor bearing failure. Accordingly, the present invention provides an improved mechanical floating aerator for oxygen transfer for biological treatment of wastewater which comprises a float (1) made of non corrosive light weight material, diffuser assembly (2), a shaft (3) passing and concentrically placed through the said assembly (2), the said shaft (3) also passing through the. bearing (7) and impeller (4) is mounted on the shaft (3) at the non driving end, at the driving end, the shaft (3) passes through and supported by characterized in that the pair of taper roller bearing (5) and coupled to a conventional prime mover (8) through a flanged coupling (6). In an embodiment of the present invention, the float (1) usad may be made of Fibre Reinforced Plastic (FRP)/stainiess steel sheets. In another embodiment of the present invention, the bearing (7) used may be made of Teflon/Bronze. In yet another embodiment of the present invention, the automatic grease feeders (9) are fixed to supply grease to bearings (5) for lubrication purpose and to prevent entry of wastewater into bearing assembly an oil seal (10) may be provided. An improved floating aerator for the biological treatment of biodegradable liquid wastes as shown in Fig. 2 of the drawing accompanying this specification, comprises a single annular float made of Fibre Reinforced Plastic (FRP) polyurethane filled body (1) diffuser assembly (2) stainless steel shaft (3) bronze impeller (4} taper roller bearings (5), flange coupling (6), teflon bush (7) and a prime mover (Electric motor) (8). On rotation of shaft by starting prime mover, the impeller rotates and suck wastewater from bottom and throw it out thus creating turbulence and breaking water bodies into drops. These water drops come in intimate contact with air and thus oxygen transfer take place for metabolic activities of microorganisms responsible for biodegradation and purification of wastewater. In the improved floating aerator, deflection and misalignment of shaft have been minimised by introducing a pair of taper roller bearings (5) and flanged coupling (6) and this is the novelty and unique features of improved mechanical floating aerator. Shaft Deflection For shaft deflection calculation, it is assumed that the loading on the shaft consists of weight of impeller and the dynamic radial thrust due to the aerator hydraulics. The shaft deflection at any point along the shaft between impeller and bearings can be calculated from following equation (Equation Removed) Reference Hydraulic design - Vol. S. Lobanolt X = Distance of impeller from a location on shaft where deflection is to be calculated (in.) Y = Deflection (inch.) W = Impeller weight (Ibs) E = Modulus of elasticity of shaft (pc's) D = Dia of shaft = Moment of inertia of shaft (in. ) πD/64 A = Area of shaft cross section (sq.in) In order to have minimum value of deflection, the distance A2 should be minimum and as practicable. Advantages: 1. The present device is econorrical eco-friendly and has a long life. 2. It minimises deflection and misalignment of shaft thus results in high efficiency. 3. Achieves uniform continuous effective stirring even at high speed resulting into formation of micro droplets of waste water. We Claim: 1. An improved mechanical floating aerator for oxygen transfer for biological treatment of wastewater which comprises a float (1) made of non corrosive light weight material, diffuser assembly (2), a shaft (3) passing and concentrically placed through the said assembly (2), the said shaft (3) also passing through the. bearing (7) and impeller (4) is mounted on the shaft (3) at the non driving end, at the driving end, the shaft (3) passes through and supported by characterized in that the pair of taper roller bearing (5) and coupled to a conventional prime mover (8) through a flanged coupling (6). 2. An improved floating aerator as claimed in claim (1), wherein the float used is made of Fibre Reinforced Plastic (FRP) Polyurethane filled /stainless steel. 3. An improved mechanical floating aerator as claimed in claims 1 and 2 where in a pair of taper roller bearings used is 130 x 31 x 26 mm size. 4. An improved mechanical floating aerator as claimed in claims 1 to 3 where in the bearing (7) is made of teflon / bronze. 4. An improved mechanical floating aerator for oxygen transfer for biological treatment of waste water as here in described with reference to the drawings accompanying this specification.

Full Text

This invention dates to an improved mechanical floating aerator for oxygen transfer for biological treatment of wastewater. The present invention relates to environmental engineering field and more particularly to be activated sludge process in aerobic treatment of domestic and industrial wastewater. Conventionally aerobic purification of biodegradable waste is carried out through (i) Fixed bridge mounted mechanical aerator (ii) Floating type low speed mechanical aerators and (iii) Floating type high speed mechanical aerators.
The conventional fixed bridge mounted aerators are particularly useful when large treatment capacity is required. Fixed type aerators are bulky and require civil construction platform for mounting. Therefore, this is not useful from economical point of view.
Floating type low speed aerators are quite bulky and require floats of large sizes to keep the aerator floating. Also their oxygen transfer capacity is less because of low R.P.M.
Floating type high speed mechanical aerators presently in use is mainly of one type viz. high speed floating aerator. This type of floating aerator has been mainly used fot aerobic biological treatment of wastewater. It suffers from the uneven distribution ct load, more vibrations, motor bearing failure and bending of shaft together with problems of misalignment and deflection. Fig. 1 shown in the drawings accompanying this specification depicts the salient features of hither to known high speed floating aerator. It comprises of an impeller (1) made of bronze mounted at the non driving end on a shaft (2). Shaft (2) supported by Teflon bush (3) and at driving end of

shaft a flanged coupling (4) is fixed and coupled with prime mover (H, the whole diffuse assembly (6) is mounted on a Fibre Reinforced Plastic (FRP) float body (7). When the prime mover (an electric motor) starts, it drives the shaft on which, at non driving end an impeller is mounted and this results in rotational motion of the impeller. This relational motion of impeller sucks wastewater from bottom and throw it out with turbulence/water droplets so as to come in contact with atmospheric air and thus oxygen transfer takes place for metabolic activities of microorganisms responsible for biodegradation and purification of wastewater. The rotation of impeller provides sufficient mixing and circulation of wastewater in the aeration tank. The above said floating aerator has inherent defect of deflection and bending of shaft, motor bearing failure and misalignment and therefore not suitable and efficient for the intended purpose. It suffers from the uneven distribution of load, more vibrations, motor bearing failure and bending of shaft together with problems of misalignment and deflection.
The object of this invention is to provide an improved floating aerator for the biological treatment of liquid wastes avoiding the above referred drawbacks particularly of deflection and misalignment and preventing motor bearing failure.
Accordingly, the present invention provides an improved mechanical floating aerator for oxygen transfer for biological treatment of wastewater which comprises a float (1) made of non corrosive light weight material, diffuser assembly (2), a shaft (3) passing and concentrically placed through the said assembly (2), the said shaft (3) also passing through the. bearing (7) and impeller (4) is mounted on the shaft (3) at the non driving end, at the driving end, the shaft (3) passes through and supported by characterized in that the pair of taper roller bearing (5) and coupled to a conventional prime mover (8) through a flanged coupling (6).
In an embodiment of the present invention, the float (1) usad may be made of Fibre Reinforced Plastic (FRP)/stainiess steel sheets.
In another embodiment of the present invention, the bearing (7) used may be made of Teflon/Bronze.
In yet another embodiment of the present invention, the automatic grease feeders (9) are fixed to supply grease to bearings (5) for lubrication purpose and to prevent entry of wastewater into bearing assembly an oil seal (10) may be provided.
An improved floating aerator for the biological treatment of biodegradable liquid wastes as shown in Fig. 2 of the drawing accompanying this specification, comprises a single annular float made of Fibre Reinforced Plastic (FRP) polyurethane filled body (1) diffuser assembly (2) stainless steel shaft (3) bronze impeller (4} taper roller bearings (5), flange coupling (6), teflon bush (7) and a prime mover (Electric motor) (8). On rotation of shaft by starting prime mover, the impeller rotates and suck wastewater from bottom and throw it out thus creating turbulence and breaking water bodies into drops. These water drops come in intimate contact with air and thus oxygen transfer take place for metabolic activities of microorganisms responsible for biodegradation and purification of wastewater.
In the improved floating aerator, deflection and misalignment of shaft have been minimised by introducing a pair of taper roller bearings (5) and flanged coupling (6) and this is the novelty and unique features of improved mechanical floating aerator.
Shaft Deflection
For shaft deflection calculation, it is assumed that the loading on the shaft consists of weight of impeller and the dynamic radial thrust due to the aerator hydraulics. The shaft deflection at any point along the shaft between impeller and bearings can be calculated from following equation
(Equation Removed)
Reference Hydraulic design - Vol. S. Lobanolt
X = Distance of impeller from a location on shaft where deflection is to be calculated (in.)
Y = Deflection (inch.)
W = Impeller weight (Ibs)
E = Modulus of elasticity of shaft (pc's)
D = Dia of shaft
= Moment of inertia of shaft (in. ) πD/64
A = Area of shaft cross section (sq.in)
In order to have minimum value of deflection, the distance A2 should be minimum and as practicable.
Advantages:
1. The present device is econorrical eco-friendly and has a long life.
2. It minimises deflection and misalignment of shaft thus results in high
efficiency.
3. Achieves uniform continuous effective stirring even at high speed resulting
into formation of micro droplets of waste water.

We Claim:
1. An improved mechanical floating aerator for oxygen transfer for biological
treatment of wastewater which comprises a float (1) made of non
corrosive light weight material, diffuser assembly (2), a shaft (3) passing
and concentrically placed through the said assembly (2), the said shaft (3)
also passing through the. bearing (7) and impeller (4) is mounted on the
shaft (3) at the non driving end, at the driving end, the shaft (3) passes
through and supported by characterized in that the pair of taper roller
bearing (5) and coupled to a conventional prime mover (8) through a
flanged coupling (6).
2. An improved floating aerator as claimed in claim (1), wherein the float used
is made of Fibre Reinforced Plastic (FRP) Polyurethane filled /stainless
steel.
3. An improved mechanical floating aerator as claimed in claims 1 and 2
where in a pair of taper roller bearings used is 130 x 31 x 26 mm size.
4. An improved mechanical floating aerator as claimed in claims 1 to 3 where
in the bearing (7) is made of teflon / bronze.
4. An improved mechanical floating aerator for oxygen transfer for biological treatment of waste water as here in described with reference to the drawings accompanying this specification.

Documents:

254-del-2000-abstract.pdf

254-del-2000-claims.pdf

254-del-2000-correspondence-others.pdf

254-del-2000-correspondence-po.pdf

254-del-2000-description (complete).pdf

254-del-2000-drawings.pdf

254-del-2000-form-1.pdf

254-del-2000-form-19.pdf

254-del-2000-form-2.pdf

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Patent Number

217676

Indian Patent Application Number

254/DEL/2000

PG Journal Number

17/2008

Publication Date

25-Apr-2008

Grant Date

28-Mar-2008

Date of Filing

16-Mar-2000

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110 001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	SANTOSH NARAYAN KAUL	NATIONAL ENVIRONMENTAL ENGINEERING RESEARCH INSTITUTE, NAGPUR - 440 020, MAHARASHTRA, INDIA.
2	NATHURAM GENDLAL SWARNAKAR	NATIONAL ENVIRONMENTAL ENGINEERING RESEARCH INSTITUTE, NAGPUR - 440 020, MAHARASHTRA, INDIA.

PCT International Classification Number

B01J 23/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA