Title of Invention	DUAL DRIVE DEVICE FOR AN AIR PREHEATER.
Abstract	This invention relates to a dual drive device for an air preheater comprising a speed reducer (03) having a base (08), atleast two input shafts eccentrically disposed, and an output shaft, the base (08) being mounted on the Airpreheater rotor housing) an electric motor (01) coupled to one end of the input shaft of the speed reducer via a fluid coupling (02); an air motor (07) coupled to the other end of the input shaft of the speed reducer via Bibby coupling (06); a pinion rack (OA) rigidly fixed on the rotor of the Airpreheater; a pinion (05) centrally mounted on the output shaft of the speed reducer (03) adaptable to engage or disengage with the pinion rack (04). A sliding means (09) comprising atleast one crank (10) mounted on the base (08), is provided which accommodates the output shaft such that a rotation of the crank (10) causes one of a forward and backward movement of the speed reducer (03) in reference to the Airpreheater thereby allowing one of an engagement and disengagement of the pinion (05) with the pin rack (04).

Title of Invention

DUAL DRIVE DEVICE FOR AN AIR PREHEATER.

Abstract

This invention relates to a dual drive device for an air preheater comprising a speed reducer (03) having a base (08), atleast two input shafts eccentrically disposed, and an output shaft, the base (08) being mounted on the Airpreheater rotor housing) an electric motor (01) coupled to one end of the input shaft of the speed reducer via a fluid coupling (02); an air motor (07) coupled to the other end of the input shaft of the speed reducer via Bibby coupling (06); a pinion rack (OA) rigidly fixed on the rotor of the Airpreheater; a pinion (05) centrally mounted on the output shaft of the speed reducer (03) adaptable to engage or disengage with the pinion rack (04). A sliding means (09) comprising atleast one crank (10) mounted on the base (08), is provided which accommodates the output shaft such that a rotation of the crank (10) causes one of a forward and backward movement of the speed reducer (03) in reference to the Airpreheater thereby allowing one of an engagement and disengagement of the pinion (05) with the pin rack (04).

Full Text	FIELD OF INVENTION The present invention relates to a Dual Drive system for Rotary Regenerative Airpreheaters. The present invention particularly relates to Rotary Regenerative heat exchangers generally used as Airpreheaters and more particularly relates to a novel Dual Drive device for the Airpreheater to avoid the stoppage of Airpreheater due to failure of the main Rotor Drive system. BACKGROUND OF THE INVENTION Rotary Regenerative Airpreheaters are used in Thermal power stations/Industrial applications to transfer the heat from the flue gas leaving boiler/furnace to the combustion air entering through regenerative heat transfer surface in a rotor, the heat transfer surface continuously turning through the air and gas streams. The rotor is divided into compartments by a number of radially extending plates referred to as diaphragms. These compartments are adapted to hold modular heat exchange baskets which contain the mass of heat absorbent material commonly formed of stacked plate-like elements. In a typical Rotary Regenerative heat exchanger, the hot flue gas and the combustion air enter the rotor shell from opposite ends and pass in opposite directions over the heat exchange material housed within the rotor. Consequently, the cold air inlet and the cooled gas outlet are at one end of the heat exchanger, referred to as the cold end, and the hot gas inlet and the heated air outlet are at the opposite end of the heat exchanger, referred to as the hot end. The Airpreheater is divided into a flue gas sector and a plurality of combustion air sectors formed by sector plates. Flexible radial seals on the rotor, usually mounted on the top and bottom edges of the diaphragms, disposed in close proximity to the sector plates and minimize leakage of gas and air between the sectors, thereby separating the air and the flue gas streams from each other. Likewise a rotor shell is mounted to the outboard end of the diaphragms, forming the periphery of the rotor, which prevents the air and gas streams from flowing through the peripheral ends of the sectors and bypassing the heat transfer surface. Circumferential seals seal the gap between the rotor and the rotor housing to prevent bypass flow through the annulus formed between the rotor and the rotor housing. The Rotary Regenerative Airpreheater consists of Rotor assembly, Rotor drive, support Bearing assembly, Guide Bearing assembly, Connecting plates and Rotor housing. The housing surrounding the rotor is provided with duct connections at both ends and adequately sealed by radial and axial sealing members. Regenerative Airpreheater is rotated by the drive system. The drive system consists of an Electric motor, an Air Motor, a Speed reducer, a Pinion, a Fluid coupling and a Bibby coupling. The driving force for 'turning the rotor' is applied at its periphery. A pinion attached to the low speed shaft of a power driven speed reducer engages a pin rack mounted on the rotor shell. The Auxiliary drive motor (Air Motor) is operated as and when the electric power supply to the electric motor gets failed. This ensures the continuous opeation of the Airpreheater. The Auxiliary drive motor also used to operate the rotor during water washing of the heating surface. The speed reducer is provided with an auxiliary high speed shaft extension, thus permitting the installation of the auxiliary drive motor at any time. If any one of the components fails during the operation, then the Airpreheater is to be stopped to rectify the problem in the drive system. Due to the stoppage of one Airpreheater, the Boiler load will come down. To overcome the above disadvantage of stoppage of Airpreheater, it is necessary to provide dual drive device, so that the other drive can be engaged to operate the Airpreheater with out stopping. Thus, the problem of rectification of a failed component can be undertaken without stoppage of the Airpreheater. OBJECTS OF THE INVENTION It is therefore an object of the present invention to provide a dual drive device for an Airpreheater which eliminates all the disadvantages of the psrior art Rotor Drive system in the Airpreheaters. Another object of the invention is to provide a dual drive device for an Airpreheater which does not require stoppage of the Airpreheater to rectify the defects due to failure in the drive system. A further object of the invention is to provide a dual drive device for an Airpreheater which is easy to maintain. A still further object of the invention is to provide a dual drive device for an Airpreheater which reduces the down time of the Boiler. SUMMARY OF THE INVENTION Accordingly there is provided a Dual drive device for an Airpreheater comprising a speed reducer having a base, at least two input shafts eccentrically disposed, and an output shaft, the base being mounted on the Airpreheater rotary housing an electric motor coupled to one end of the input shaft via a fluid coupling an air motor coupled to the other end of the input shaft via a Bibby coupling; a pinion rack rigidly fixed on the rotor of the Airpreheater; a pinion centrally mounted on the output shaft of the speed reducer adaptable to engage or disengage with the pinion rack. A sliding means comprising atleast one crank mounted on the base, is provided which accommodates the output shaft such that a rotation of the crank causes forward or backward movement of the speed reducer in reference to the Airpreheater thereby allowing engagement or disengagement of the pinion with the pinion rack. Thus, in the present invention two separate drive means are installed for one Airpreheater. Only one drive means is engaged at a time for operation of the Airpreheater. If any problem arise in the drive means, then the drive means can be disengaged from the rotor for maintenance. Simultaneously, the other drive means can be engaged for operation of the Airpreheater, thereby stoppage of the Airpreheater can be avoided and the down time of the boiler reduced. BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURE Figure 1 - Shows a dual drive device in an Airpreheater according to the invention. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION According to present invention, the Regenerative Airpreheater have two separate drive means. One drive means is operated at a time. The other drive means is kept stand by. The Regenerative Airpreheater is rotated by the drive device. The drive device consists of an Electric motor, Air motor, Speed reducer, Pinion, Reducer base, Sliding means, Fluid coupling and Bibby coupling. As illustrated in figure 1, the constructive features of the Dual drive device is that a speed reducer (03) has two input shaft and one output shaft and is mounted on a sliding means (09). The sliding means (09) consists of screw, slides and crank (10) being mounted on a base (08) of the speed reducer. An electric motor (01) is coupled with the input shaft of the reducer at one end via a Fluid coupling (02). Similarly, an air motor (07) is coupled with the input shaft of the reducer at other end via a Bibby coupling (06). A pinion (05) is mounted on an output shaft of the speed reducer and is engaged with a pin rack (04) in a rotor shell during operation of the Airpreheater. The pinion (05) is covered with a pinion cover to avoid settling of the ash particles on the pinion and to avoid the leakage of air through the pin rack (04) from the Airpreheater. The reducer base (08) is fixed on a housing of the Airpreheater rotor. By rotating the crank (10) in the sliding means (09), the speed reducer (03) can be moved from / towards the Airpreheater for disengagement / engagement between the pinion (05) and the pin rack (04). The typical Dual Drive device is shown in the accompanying drawing. We Claim 1. A Dual drive device for an Airpreheater comprising: - a speed reducer (03) having a base (08), atleast two input shafts eccentrically disposed, and an output shaft, the base (08) being mounted on the Airpreheater rotor housing; - an electric motor (01) coupled to one end of the input shaft of the speed reducer via a fluid coupling (02); - an air motor (07) coupled to the other end of the input shaft of the speed reducer via a Bibby coupling (06); - a pinion rack (04) rigidly fixed on the rotor of the Airpreheater; - a pinion (05) centrally mounted on the output shaft of the speed reducer (03) adaptable to engage or disengage with the pinion rack (04), characterized in that a sliding means (09) comprising atleast one crank (10) mounted on the base (08), is provided which accommodates the output shaft such that a rotation of the crank (10) causes one of a forward and backward movement of the speed reducer (03) in reference to the Airpreheater thereby allowing one of an engagement and disengagement of the pinion (05) with the pin rack (04). 2. The device as claimed in claim 1, wherein the sliding means (09) comprises a plurality of slides. 3. A Dual drive device for an Airpreheater as substantially described herein with reference to the accompanying drawings. This invention relates to a dual drive device for an air preheater comprising a speed reducer (03) having a base (08), atleast two input shafts eccentrically disposed, and an output shaft, the base (08) being mounted on the Airpreheater rotor housing) an electric motor (01) coupled to one end of the input shaft of the speed reducer via a fluid coupling (02); an air motor (07) coupled to the other end of the input shaft of the speed reducer via Bibby coupling (06); a pinion rack (OA) rigidly fixed on the rotor of the Airpreheater; a pinion (05) centrally mounted on the output shaft of the speed reducer (03) adaptable to engage or disengage with the pinion rack (04). A sliding means (09) comprising atleast one crank (10) mounted on the base (08), is provided which accommodates the output shaft such that a rotation of the crank (10) causes one of a forward and backward movement of the speed reducer (03) in reference to the Airpreheater thereby allowing one of an engagement and disengagement of the pinion (05) with the pin rack (04).

Full Text

FIELD OF INVENTION
The present invention relates to a Dual Drive system for Rotary Regenerative
Airpreheaters. The present invention particularly relates to Rotary Regenerative
heat exchangers generally used as Airpreheaters and more particularly relates to
a novel Dual Drive device for the Airpreheater to avoid the stoppage of
Airpreheater due to failure of the main Rotor Drive system.
BACKGROUND OF THE INVENTION
Rotary Regenerative Airpreheaters are used in Thermal power stations/Industrial
applications to transfer the heat from the flue gas leaving boiler/furnace to the
combustion air entering through regenerative heat transfer surface in a rotor, the
heat transfer surface continuously turning through the air and gas streams.
The rotor is divided into compartments by a number of radially extending plates
referred to as diaphragms. These compartments are adapted to hold modular
heat exchange baskets which contain the mass of heat absorbent material
commonly formed of stacked plate-like elements.
In a typical Rotary Regenerative heat exchanger, the hot flue gas and the
combustion air enter the rotor shell from opposite ends and pass in opposite
directions over the heat exchange material housed within the rotor.
Consequently, the cold air inlet and the cooled gas outlet are at one end of the
heat exchanger, referred to as the cold end, and the hot gas inlet and the heated
air outlet are at the opposite end of the heat exchanger, referred to as the hot
end.
The Airpreheater is divided into a flue gas sector and a
plurality of combustion air sectors formed by sector plates.
Flexible radial seals on the rotor, usually mounted on the top
and bottom edges of the diaphragms, disposed in close proximity
to the sector plates and minimize leakage of gas and air between
the sectors, thereby separating the air and the flue gas streams
from each other. Likewise a rotor shell is mounted to the
outboard end of the diaphragms, forming the periphery of the
rotor, which prevents the air and gas streams from flowing
through the peripheral ends of the sectors and bypassing the heat
transfer surface. Circumferential seals seal the gap between the
rotor and the rotor housing to prevent bypass flow through the
annulus formed between the rotor and the rotor housing.
The Rotary Regenerative Airpreheater consists of Rotor assembly,
Rotor drive, support Bearing assembly, Guide Bearing assembly,
Connecting plates and Rotor housing. The housing surrounding the
rotor is provided with duct connections at both ends and
adequately sealed by radial and axial sealing members.
Regenerative Airpreheater is rotated by the drive system. The
drive system consists of an Electric motor, an Air Motor, a
Speed reducer, a Pinion, a Fluid coupling and a Bibby coupling.
The driving force for 'turning the rotor' is applied at its
periphery. A pinion attached to the low speed shaft of a power
driven speed reducer engages a pin rack mounted on the rotor
shell. The Auxiliary drive motor (Air Motor) is operated as and
when the electric power supply to the electric motor gets failed.
This ensures the continuous opeation of the Airpreheater. The
Auxiliary drive motor also used to operate the rotor during water
washing of the heating surface. The speed reducer is provided
with an auxiliary high speed shaft extension, thus permitting the
installation of the auxiliary drive motor at any time. If any
one of the components fails during the operation, then the
Airpreheater is to be stopped to rectify the problem in the drive
system. Due to the stoppage of one Airpreheater, the Boiler load
will come down. To overcome the above disadvantage of stoppage
of Airpreheater, it is necessary to provide dual drive device, so
that the other drive can be engaged to operate the Airpreheater
with out stopping. Thus, the problem of rectification of a failed
component can be undertaken without stoppage of the Airpreheater.
OBJECTS OF THE INVENTION
It is therefore an object of the present invention to provide a
dual drive device for an Airpreheater which eliminates all the
disadvantages of the psrior art Rotor Drive system in the
Airpreheaters.
Another object of the invention is to provide a dual drive device
for an Airpreheater which does not require stoppage of the
Airpreheater to rectify the defects due to failure in the drive
system.
A further object of the invention is to provide a dual drive
device for an Airpreheater which is easy to maintain.
A still further object of the invention is to provide a dual
drive device for an Airpreheater which reduces the down time of
the Boiler.
SUMMARY OF THE INVENTION

Accordingly there is provided a Dual drive device for an
Airpreheater comprising a speed reducer having a base, at least
two input shafts eccentrically disposed, and an output shaft, the
base being mounted on the Airpreheater rotary housing an electric
motor coupled to one end of the input shaft via a fluid coupling an
air motor coupled to the other end of the input shaft via a Bibby coupling; a
pinion rack rigidly fixed on the rotor of the Airpreheater; a pinion centrally
mounted on the output shaft of the speed reducer adaptable to engage or
disengage with the pinion rack. A sliding means comprising atleast one crank
mounted on the base, is provided which accommodates the output shaft such
that a rotation of the crank causes forward or backward movement of the speed
reducer in reference to the Airpreheater thereby allowing engagement or
disengagement of the pinion with the pinion rack. Thus, in the present invention
two separate drive means are installed for one Airpreheater. Only one drive
means is engaged at a time for operation of the Airpreheater. If any problem
arise in the drive means, then the drive means can be disengaged from the rotor
for maintenance. Simultaneously, the other drive means can be engaged for
operation of the Airpreheater, thereby stoppage of the Airpreheater can be
avoided and the down time of the boiler reduced.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURE
Figure 1 - Shows a dual drive device in an Airpreheater according to the
invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF
THE INVENTION
According to present invention, the Regenerative Airpreheater have two separate
drive means. One drive means is operated at a time. The other drive means is
kept stand by. The Regenerative Airpreheater is rotated by the drive device. The
drive device consists of an Electric motor, Air motor, Speed reducer, Pinion,
Reducer base, Sliding means, Fluid coupling and Bibby coupling.
As illustrated in figure 1, the constructive features of the Dual drive device is that
a speed reducer (03) has two input shaft and one output shaft and is mounted
on a sliding means (09). The sliding means (09) consists of screw, slides and
crank (10) being mounted on a base (08) of the speed reducer. An electric motor
(01) is coupled with the input shaft of the reducer at one end via a Fluid coupling
(02). Similarly, an air motor (07) is coupled with the input shaft of the reducer at
other end via a Bibby coupling (06). A pinion (05) is mounted on an output shaft
of the speed reducer and is engaged with a pin rack (04) in a rotor shell during
operation of the Airpreheater. The pinion (05) is covered with a pinion cover to
avoid settling of the ash particles on the pinion and to avoid the leakage of air
through the pin rack (04) from the Airpreheater. The reducer base (08) is fixed
on a housing of the Airpreheater rotor. By rotating the crank (10) in the sliding
means (09), the speed reducer (03) can be moved from / towards the
Airpreheater for disengagement / engagement between the pinion (05) and the
pin rack (04). The typical Dual Drive device is shown in the accompanying
drawing.
We Claim
1. A Dual drive device for an Airpreheater comprising:
- a speed reducer (03) having a base (08), atleast two input shafts
eccentrically disposed, and an output shaft, the base (08) being
mounted on the Airpreheater rotor housing;
- an electric motor (01) coupled to one end of the input shaft of the
speed reducer via a fluid coupling (02);
- an air motor (07) coupled to the other end of the input shaft of the
speed reducer via a Bibby coupling (06);
- a pinion rack (04) rigidly fixed on the rotor of the Airpreheater;
- a pinion (05) centrally mounted on the output shaft of the speed
reducer (03) adaptable to engage or disengage with the pinion rack
(04), characterized in that a sliding means (09) comprising atleast
one crank (10) mounted on the base (08), is provided which
accommodates the output shaft such that a rotation of the crank
(10) causes one of a forward and backward movement of the
speed reducer (03) in reference to the Airpreheater thereby
allowing one of an engagement and disengagement of the pinion
(05) with the pin rack (04).
2. The device as claimed in claim 1, wherein the sliding means (09)
comprises a plurality of slides.
3. A Dual drive device for an Airpreheater as substantially described herein
with reference to the accompanying drawings.
This invention relates to a dual drive device for an air
preheater comprising a speed reducer (03) having a base (08),
atleast two input shafts eccentrically disposed, and an output
shaft, the base (08) being mounted on the Airpreheater rotor
housing) an electric motor (01) coupled to one end of the input
shaft of the speed reducer via a fluid coupling (02); an air
motor (07) coupled to the other end of the input shaft of the
speed reducer via Bibby coupling (06); a pinion rack (OA) rigidly
fixed on the rotor of the Airpreheater; a pinion (05) centrally
mounted on the output shaft of the speed reducer (03) adaptable
to engage or disengage with the pinion rack (04). A sliding means
(09) comprising atleast one crank (10) mounted on the base (08),
is provided which accommodates the output shaft such that a
rotation of the crank (10) causes one of a forward and backward
movement of the speed reducer (03) in reference to the
Airpreheater thereby allowing one of an engagement and
disengagement of the pinion (05) with the pin rack (04).

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Patent Number

224703

Indian Patent Application Number

00428/KOL/2005

PG Journal Number

43/2008

Publication Date

24-Oct-2008

Grant Date

22-Oct-2008

Date of Filing

24-May-2005

Name of Patentee

BHARAT HEAVY ELECTICALS LIMITED

Applicant Address

REGIONAL OPERATIONS DIVISION(ROD), PLOT NO : 9/1, DJBLOCK, 3RD FLOOR, KARUNAMOYEE, SALT LAKE CITY, KOLKATA-700091

Inventors:

#	Inventor's Name	Inventor's Address
1	SHRI GANAPATHY RAMAMURTHY VENKATARAMAN	BHARAT HEAVY ELECTRICALS LIMITED, RANIPET-632406
2	SHRI KANDAVEL PALANICHAMY	BHARAT HEAVY ELECTRICALS LIMITED, RANIPET-632406
3	SHRI RAMASAMY DHANDAPANY	BHARAT HEAVY ELECTRICALS LIMITED, RANIPET-632406

PCT International Classification Number

F22D 1/36

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA