FIELD OF INVENTION
The invention relates to rapping mechanism of emitting electrodes of Electrostatic Precipitator (ESP), an air pollution control equipment widely used for collecting dust particles from flue gas exhausted by thermal power plants, cement plants, steel plants and glass plants etc. The invention provides a single unit rapping mechanism for all the ESP fields, instead of individual rapping mechanism for individual field.
BACKGROUND OF THE INVENTION
An Electrostatic Precipitator (ESP) is a particulate collection device that removes particles from a flowing gas (such as air) using the force of an induced electrostatic charge. Electrostatic precipitators are highly efficient filtration devices that minimally impede the flow of gases through the device, and can easily remove fine particulate matter such as dust and smoke from the air stream.
The dust laden particles are electrically charged through emitting electrode (EE) and in the presence of high electric field between the electrodes, charged dust particles experience a force which causes the particles to move towards the collecting electrodes and finally get deposited over collecting plate. During the process some dust particles also gets deposited on the surface of the EE and its frame. In order to

maintain the desired efficiency and to avoid back corona it is very essential that this dust accumulation should be removed at regular interval.
The deposited dust particle over EE will get dislodged through rapping mechanism
and get collected in hopper. The collected fly ash gets evacuated by Ash handling
system.
Rapping mechanism consist of Geared motor, shaft and hammer for rapping EE. In
the existing arrangement, each ESP field will have individual rapping motor to perform
the rapping functions. Hence, more number of geared motor is required for a project.
As an improvement project a new arrangement has been made with single geared motor to perform the rapping of emitting frame for all the ESP fields. This arrangement will reduce number of geared motor and other accessories cost.
At present individual EE rapping geared motor is provided for each field of the ESP. This in turns calls for higher number of geared motor, which involves higher maintenance cost and more auxiliary power consumption.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to develop a method for replacing all the rapping geared motors with a Single Geared Motor, reducing the motor nos.

Another object of the invention is to reduce the Auxiliary Power consumption, by reducing number of geared motors.
Yet another object of the invention is to reduce the cost of ESP by way of reducing material cost of motors and associated components.
A still further object of the invention is to reduce the maintenance problem of plant, by reducing number of geared motors and using stand-by motor during emergency.
SUMMARY OF THE INVENTION
The present innovation provides a novel method for eliminating the individual EE rapping geared motor for each field and introducing the Single drive arrangement for the Entire field of the ESP. Drive is provided to each field of the ESP by using Pinwheel arrangement from the continuous shaft throughout length of the ESP.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 – shows an isometric view of a typical Electrostatic Precipitator (ESP).
Figure 2 – shows collecting and emitting electrodes.
Figure 3 - Isometric view of Single Drive EE Rapping Assembly.

Figure 4 - Inclined view (with Parts Numbering) of Single drive EE rapping mechanism.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION
The Electrostatic precipitator as shown figure-1 & 2 essentially consists of two sets of electrodes called Collecting Electrodes (01) and Emitting Electrodes (02) (also called discharge electrodes). A unidirectional high voltage is applied between these electrodes, connecting its negative polarity to the emitting electrodes and the positive polarity to collecting electrodes, which are also earthed. The dust laden flue gas from boiler passes between rows of collecting and discharge electrodes.
The high voltage induces ionization of gas molecules adjacent to the negatively charged emitting electrodes. The positive charges of the ions created travel towards the discharge electrodes and the negative charges towards the collecting electrodes. On their way to the collecting electrodes, the negative charges get deposited on the dust particles.
Thus the dust particles are electrically charged. In the presence of high electric field between the electrodes the charged dust particles experience a force which causes the particles to move towards the collecting electrodes and finally get deposited on

them. Minor portions of the dust particles, which have acquired positive charges, get deposited on the emitting electrodes also. Periodically these are dislodged from the electrodes by a process called ‘rapping’. The particles then fall into the hoppers at the bottom.
The purpose of providing the EE rapping mechanism is to dislodge the ash deposited on the EE wire.
Rapping Motor for all the fields are replaced with a common rapping motor (11) of designed capacity, which is placed on the Platform (03). A common Horizontal shaft-1
is connected to Rapping motor (11) and run along the length of through-out all the fields. Pinwheel-1(04) of each field is mounted on horizontal shaft-1 (06). Stopper
is connected to extreme end of horizontal shaft-1(06). The Pinwheel-2 (05) has been connected to one end of vertical shaft (08) and is supported on the support bracket (16). Other end of vertical shaft (08) is being connected with Pinwheel-3(14). One end of another Horizontal shaft-2(09), installed inside ESP, has been connected to Pinwheel-4 (13), which is engaged with Pinwhell-3(14). Rapping hammers (10) are connected radially with certain interval to the horizontal shaft -2 (09). Since, horizontal shaft-2 (09) is sent in smaller pieces, this will be coupled one another with sleeve bearing (12) to form a single piece. Drive from rapping motor (11) is transmitted to horizontal shaft-2 (09) through set of pinwheel-1 & pinwheel-2 and pinwheel-3 & pinwheel-4. Pinwheel-4(13) has been designed for larger diameter to

reduce the speed of horizontal shaft-2(09) to have effecting rapping of emitting system. The total emitting rapping system is placed over ESP outer roof (15). Additional one redundancy rapping motor is provided to connect the rapping system during any non-functional of existing motor (11).
The direction of horizontal shaft-1 (06) rotation has been changed through pinwheel-1(04) and pinwheel-2(05), which are connected perpendicularly. Similarly, the direction of vertical shaft (08) has been changed through pinwheel-3(14) and pinwheel-4(13), which are also connected perpendicularly.

WE CLAIM
1. A system and a method for improvement of rapping mechanism of emitting
electrodes (02) of an electrostatic precipitator comprising:
Rapping motor (11)
i) Pinwheel – 1(04), ii) Pinwheel – 2(05), iii) Pinwheel – 3(14), iv) Pinwheel – 4(13)
i) Horizontal shaft – 1(06), ii) Horizontal shaft - (09)
Vertical shaft – (08)
Support bracket (16)
Sleeve bearing – (12)
Rapping hammer - (10)
Characterized by a single common drive through the motor (11), shaft (06) in association with respective pin wheels, horizontal and vertical shafts, support bracket, sleeve bearing rapping hammer etc.
2. A method of improvement for rapping mechanism of emitting electrode of an ESP
as claimed in claim 1, wherein the rapping motor (11) placed on platform (3),
replaces all the individual rapping geared motors in series used in individual fields.

The method as claimed in claim 2, wherein a common horizontal shaft – 1(6), connected to rapping motor and running along throughout all the fields, changing direction of rotation through Pinwheel – 1(04) and Pinwheel – 2(05).
The method as claimed in claim 2, wherein Pinwheel – 1(04) of each field is mounted on horizontal shaft – 1(06).
The method as claimed in claim 4, wherein the stopper (7), connected to extreme end of the horizontal shaft – 1(06) restricting the movements of shafts.
The method as claimed in claim 5, wherein Pinwheel – 2(5), connected to one end of the vertical shaft (08) and supported by the bracket (16).
The method as claimed in claim 2, wherein Pinwheel – 3(14), connected to other end of the vertical shaft (08).
The method as claimed in claim 2, wherein Pinwheel – 4(13) connected to one end of the another horizontal shaft – 2(09) and engaged with Pinwheel – 3(14).
The method as claimed in claim 1, wherein horizontal shaft – 2(09), having smaller pieces, coupled to one another by sleeve bearing (12) forming a single piece.

10.The method as claimed in claim 2, wherein the vertical shaft (08), supported on the bracket (16), connected by pinwheel – 2(05) at one end and pinwheel – 3(14) at the other end, changes direction of rotation by Pinwheel – 3(14) and Pinwheel – 4(13).
11.The system as claimed in claim 1, wherein the drive from rapping motor (11) is transmitted to horizontal shaft – 2(09) through set of Pinwheel – 1(04), Pinwheel – 2(05), Pinwheel – 3(14) and Pinwheel – 4(13)
Characterized by, larger diameter of Pinwheel – 4(13) to reduce the speed of horizontal shaft – 2(09) for effective rapping by rapping hammers (10), connected radially at certain intervals to the horizontal shaft – 2(09).