TITLE OF THE INVENTION
Innovative method for longitudinal roof beam replacement without removing
electrostatic precipitator internal mechanical loads.
FIELD OF THE INVENTION
This invention relates to method for replacement of longitudinal roof beam of
Electrostatic Precipitator (ESP), through which, all the loads of the ESP is transferred
to super-structure. Longitudinal roof(LR) Beam is connected to Transverse roof (TR)
Beam directly, on which all the collecting electrodes (CE), emitting electrodes (EE) and
their support frame is welded. Size of LR Beam Depends upon the internal mechanical
load of ESP. As LR beam is one of the critical load bearing components of the ESP
and all the internal mechanical loads of ESP are transferred through LR Beam to
super structure, size of LR Beam Depends upon the internal mechanical load of ESP.
The invention relates to an innovative method for the replacement of LR Beam without
disturbing/removing the internals of Electrostatic precipitator.
BACKGROUND ART
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 and 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
over collecting plate. The deposited dust particle will get dislodged through rapping
mechanism and get collected in hopper. The collected fly ash gets evacuated by Ash
handling system.
Sometimes, due to improper working or chocking in ash handling system, the collected
ash particles could not be evacuated from hopper. Rat hole also formed inside hopper
during evacuation and wrong information goes to ash handling control system on
storage of ash inside hopper. This misleads the operator not to give much attention to
evacuate the ash. This resulted in accumulation of ash inside hopper and goes beyond
hopper and build-up inside ESP casing. The total CE and EE system are submerged
inside ash. The electrical fields will be out and subsequently the performance of ESP
will degrade which leads to increase in particulate emissions. During evacuation of fly
ash from ESP fields, there will be enormous drag force on collecting electrode plate,
which get transferred to Roof beams and subsequently damages the roof beams. This
results in damages of field internals and forcing power plant to shut down.
To bring power plant to in to operation, the ESP fields shall be rectified. For replacing
damaged LR beam, whole ESP internals to be dismantled, which takes more time and
in turn affects the power generations of the plant, leading to the revenue loss. To
overcome the above mentioned issues, a method has been developed for the
Longitudinal Beam Replacement without removing ESP internal mechanical Loads.

OBJECT OF THE INVENTION
It is therefore an object of the invention to develop a method for the replacement of
damaged LR beam in ESP without removing the ESP internals.
Another object of the invention is to develop a method for the replacement of damaged
LR beam in ESP without removing the ESP internals that reduces the erection cycle
time for removing and then again erecting new internals after replacing the LR beams.
A yet another object of the invention is to develop a method for the replacement of
damaged LR beam in ESP without removing the ESP internals that reduces the
material cost, as the existing internals can’t be re-used and new internals shall be
erected.
A further object of the invention is to reduce the executing cost for removing and
erecting new internals and handling of all the components during execution.
A still further object of the invention is to reduce the power plant outage, thereby
increasing the availability of power for use.
SUMMARY OF THE INVENTION
In the existing process, the damaged LR beam of ESP is getting replaced by removing
all the internals of that field of ESP. The existing internals could not further be-used as
these are very thin to have an effective rapping to dislodge ash and will get damaged
during dismantling. This process will take more time which leads to more outage of
power plant.

The present innovation provides a novel method for replacing the damaged LR beam
without removing the ESP internals which in turn reduces the cycle time of restoration of
ESP fields by replacing new LR beam. Bracket has been provided to existing casing
columns for the field damaged LR beam to be replaced. The TR beam which has been
fixed to LR beam will be isolated from damaged LR beam by transferring load of TR
beam to existing casing column through bracket. Subsequently, the damaged LR
beam replaced with new LR beam.
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 Longitudinal Beam Replacement Assembly
Figure 4 - Inclined view of Longitudinal Beam Replacement Assembly
Figure 5 - Inclined view (with Parts Numbering) of Longitudinal Beam Replacement
Assembly with hydraulic jack.
Figure 6 - Inclined view (with Parts Numbering) of Longitudinal Beam Replacement
Assembly after removing hydraulic jack
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
The Electrostatic precipitator as shown figure-1 & 2 essentially consists of two sets of
electrodes called Collecting Electrodes ( 13 ) and Emitting Electrodes ( 14 ) and

(also called discharge electrodes). A unidirectional high voltage is applied between
these electrodes, connecting its negative polarity to the emitting electrodes ( 14 ) and
the positive polarity to collecting electrodes ( 13 ) , which are also earthed. The dust
laden flue gas from boiler passes between rows of collecting ( 13 ) and discharge
electrodes ( 14 ) .
The high voltage induces ionization of gas molecules adjacent to the negatively
charged emitting electrodes ( 14 ) . The positive charges of the ions created travel
towards the discharge electrodes ( 14) and the negative charges towards the
collecting electrodes ( 13 ) .
On their way to the collecting electrodes ( 13 ) , 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 ( 13 ) 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. Longitudinal roof beam (LR beam) has been provided to hold the ESP internals
and is designed for the load of internals.
A temporary bracket arrangement (02) and Channel (03) will be welded with existing
Casing column (01) of the field LR beam to be replaced. The stool platform (04) is
placed over the channel (03).

Two stub column (05) has been welded to stool platform (04) at both the end of
Casing column (01) as shown in Figure 5.
Above stool column (05) a temporary support beam (07) is being placed, covering from
one end of casing column (01) to another end of casing column for that field. In similar
way, temporary support beam (07) has been placed over stool column to the adjacent
field. Lifting support (10) made from hollows has been welded to adjacent existing TR
beam (06). Similarly, another set of lifting support (10) shall be welded to other end of
existing TR beam (06). Hydraulic jack (12) shall be placed in between lifting support
(10) and damaged LR beam (08) as per figure 5. All existing TR beam (06) in that field
shall be trimmed and isolated from the damaged LR beam (08). Through hydraulic
jack, the existing TR beam (06) shall be lifted to maintain water level of ESP internals.
Once water levelling is maintained, before removing hydraulic jack (12), the entire
system shall be locked, by welding another square hollow section (11), which shall be
welded to both vertical post (09) and lifting support (10). Subsequently, the existing TR
beam (06) also to be locked to temporary support beam (07). This arrangement has to
be carried-out at both end of fields. With this arrangement the exiting internals
load is being transferred to existing casing column without disturbing the existing
internals.
After transferring the load of internal to existing casing column, the hydraulic jack (12)
shall be removed and horizontal portion of lifting support (10) shall be dismantled..
Damaged LR beam (08) shall be removed for that field and replaced with new LR
beam at the same location. The existing TR beam (06) shall be welded to newly placed

LR beam to transfer the internal load to LR beam. Thereafter square hollow section
(11) along with vertical post (09) shall be gouged from all existing TR beam (06).
Subsequently, temporary support beam (07) shall be dismantled from stub column
(05). Thereafter, stub column (05), stool platform (04), channel (03), and bracket
arrangement (02) shall be dismantled from casing column (01) to restore the fields
into healthy conditions.

We claim
1. A setup for longitudinal roof beam replacement without removing the electrostatic
precipitator (ESP) internal mechanical loads comprising a structure having a
plurality of stool platform (4);
the said stool platform (4) placed over plurality of channel (03);
the said channels (03) mounted over temporary bracket arrangement (02);
the said bracket arrangement (02) resting over a pair of casing column (01), the
joint between channel (03) and bracket (02) as well as between bracket (02) and
casing column (01) welded for rigidity;
a pair of stub column (05) placed and welded over each stool platform (04);
a pair of temporary support beam (7) placed over stool column (5) on either side
covering both the casing column (01);
plurality of existing TR beam (6) rigidly welded to LR beam (8) at one end and
either rigidly connected to LR beam (8) or placed over ESP wall, as the case may
be, at other end;
the said casing column (01) giving support to LR beam (8) wherein an arrangement
is made by welding a lifting support (10) in the TR beam (6) for lifting the
arrangement with the help of hydraulic jack (12) placed between the LR beam (08)
and lifting support (10) for lifting when the existing TR beam (06) in that field shall
be trimmed and isolated form the damaged LR beam (08) as well as the TR beam
(06) lifted to maintain water level of ESP Electrostatic precipitator internals followed
by locking the entire system by welding another square hollow section (11) with
vertical post (09) and lifting support (10) as well as TR beam.
2. The setup for longitudinal roof beam replacement as claimed in claim 1, wherein the
existing TR beam (6) are locked to temporary support beam (7) by welding another
square hollow section (11) before taking out the hydraulic jack (12).

3. The setup for longitudinal roof beam replacement as claimed in claim 1, wherein the
damaged LR beam (08) shall be removed after removing lifting support (10).
4. The setup for longitudinal roof beam replacement as claimed in claim 1, wherein the
new LR beam installed over casing column (01) and subsequently levelled the
existing TR beam welded to new LR beam.
5. The setup for longitudinal roof beam replacement as claimed in claim 1, wherein to
restore the fields into healthy conditions, the square hollow section (11) along with
vertical post (09) shall be gouged and removed from all existing TR beam (06)
and subsequently, temporary support beam (07) shall be dismantled from stub
column (05) and thereafter stub column (05), stool platform (04), channel (03),
and bracket arrangement (02) shall be dismantled from casing column (01).