FIELD OF THE INVENTION
This invention relates to Electrostatic Precipitator (ESP), which is a pollution
control equipment widely used for collecting dust particles from flue gas
exhausted by thermal power plants, cement plants, steel plants and glass plants.
More particularly, the invention relates to an improved device for supporting the
emitting frame set during erection and maintenance of Electrostatic Precipitators.
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 efficiency of an ESP can be enhanced by erection of internals conforming to
field quality plan. Emitting frame, which is the essential feature of an ESP is
supported by an insulator through a suspension rod. Before transferring the load
of the emitting frame to the insulator, the entire frame is first supported by a
lifting holder and assembled as per Quality plan. In an electrostatic precipitator,
the flue gas laden with fly ash is sent through a tube structure having negatively
charges plates which give the particles a negative charge. The particles are then
routed past positively charged plates or grounded plates, which attract the now
negatively- charged ash particles. The particles stick to the positive plates until
they are collected. The flue gas that leaves the plates constitutes clean gas and
free of harmful pollutants.
Negative charge plates are mounted in support frame and are negatively
charged. Total load of emitting frames are supported on an insulator through a
suspension rod. Before transferring the load of emitting frame the load of whole
frame and its accessories are held by a lifting holder.
According to the invention, the improved device is provided to support lifting
beam on which the total emitting frame is suspended. The device is the key
element for assembly of the emitting frame set. The device is required till
completion of assembly of the total frame including alignment of the frame.
Subsequently the load from the lifting holder is shifted to the suspension rod,
which is fixed on the insulator for commissioning of the ESP. The lifting holder is
also a tool and required to replace the insulator when the insulator fails due to
some reasons. The prior art lifting holder is generally made from steel rod with
one end having a bend in the shape of a hook, and for normalizing the bend
portion, a heat treatment process is carried out to relieve the internal stress.
Thus, the prior art process involves increased manufacturing cycle time and cost.
To avoid the bending process and heat treatment of the lifting holder, the
inventors recognized that the prior art lifting holder needs innovative design and
re-configuration.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose an improved device for
supporting the emitting frame set during erection and maintenance of
Electrostatic Precipitators, which eliminates the disadvantages of prior art.
Another object of the invention is to propose an improved device for supporting
the emitting frame set during erection and maintenance of Electrostatic
Precipitators; which can withstand the entire load of the emitting frame.
A still another object of the invention is to propose an improved device for
supporting the emitting frame set during erection and maintenance of
Electrostatic Precipitators, manufacturing cycle time of which device is lesser due
to elimination of the heat treatment process of constituent components of the
device.
A further object of the invention is to propose an improved device for supporting
the emitting frame set during erection and maintenance of Electrostatic
Precipitators, which reduces dismantling/reassembly period of the device during
plant maintenance.
A still further object of the invention is to propose an improved device for
supporting the emitting frame set during erection and maintenance of
Electrostatic Precipitators, which can be safely installed/re-installed.
SUMMARY OF THE INVENTION
According to the invention, the improved device is provided to support lifting
beam on which the total emitting frame is suspended. The device is the key
element for assembly of the emitting frame set. The device is required till
completion of assembly of the total frame including alignment of the frame.
Subsequently the load from the lifting holder is shifted to the suspension rod,
which is fixed on the insulator for commissioning of the ESP. The lifting holder is
also a tool and required to replace the insulator when the insulator fails due to
some reasons.
Accordingly, there is provided an improved device for supporting the emitting
frame set during erection and maintenance of Electrostatic Precipitators, which
requires reduced manufacturing cycle and cost by avoiding prior art heat
treatment and bending formation on the device. The hook member of the prior
art lifting holder is now replaced with a solid rod welded at bottom of the lifting
rod. A hollow pipe along with side stiffeners is welded on a top suspension beam
of the emitting frame.
The support device is inserted from the bottom of the hollow pipe and fastened
with a nut at the top. The lifting rod provided at the bottom carry the load of the
emitting frame.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 - shows an isometric view of a typical Electrostatic Precipitator (ESP).
Figure 2 - schematically shows a top view of the typical ESP depicting the
collecting and discharge electrodes.
Figure 3 - Shows a three dimensional representation of an improved support
device attached to the suspension beam according to the invention.
Figure 4 - Shows a three dimensional view of an improved support device of the
invention.
Figure 5 - Shows a 2-D view of the support device of the invention.
Figure 6 - Shows a 2-D view of the lifting holder of the support device of Fig.5.
Figure 7 - Shows a 2-D view of a prior art lifting holder.
DETAILED DESCRIPTION OF THE INVENTION
An Electrostatic precipitator as shown figure-1 & 2, essentially consists of two
sets of electrodes called Collecting Electrodes (CE) and Emitting Electrodes (DE)
(also called discharge electrodes). An unidirectional high voltage (UHV) is
applied between these electrodes (CE, DE), connecting its negative polarity to
the emitting electrodes (DE) and the positive polarity to the collecting electrodes
(CE), which are also earthed. The dust laden flue gas (FG) from the boiler passes
between rows of collecting and discharge electrodes (CE, DE). The applied high
voltage (UHV) induces ionization field (IF) within the gas molecules adjacent to
the negatively charged emitting electrodes (DE). The generated positive charges
of the ions travel towards the discharge electrodes (DE) and the negative
charges travel towards the collecting electrodes (CE). Upon their flow to the
collecting electrodes (CE), 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 (CE, DE), the charged dust particles experience a
force which causes the particles to move towards the collecting electrodes (CE)
and finally get deposited on the metal collection plates (MP) of the electrodes. A
small portion of the dust particles, which acquired positive charges, gets
deposited on the emitting electrodes (DE) also. Periodically these are dislodged
from the electrodes (CE, DE) by a rapper (RR). The particles then fall into the
hoppers (HR) at the bottom. Clean gas (CG) is exited through the other end of
the ESP.
Negative charge electrodes are mounted in a support frame and are negatively
charged. Total load of the emitting frames are supported on an insulator through
a suspension rod. Till transferring the load of the emitting frame, the load of
entire emitting frame set is held by the support device of the invention.
According to the invention, and as shown in figs. 5 & 6, the support device (01)
is made of a lifting Rod (09) and threaded at one end. A bottom rod (08) is
welded at the bottom of the lifting Rod (09). The length of the lifting rod (09) is
as per requirement. A lifting beam (05) is welded with a holding pipe (07) and to
avoid lateral bending, at least one stiffener (06) is welded as shown in figure-3.
The support device (01) is inserted from the bottom of the lifting beam (05). A
bush (02) and a plurality of washer plates (03) are provided before tightening a
nut (04). The assembly of the support device (01) is supported on ESP roof until
the frame load is transferred to the insulator. The verticality of the frame is
maintained by adjusting the nut (04).
WE CLAIM
1. An improved device for supporting the emitting frame set during erection
and maintenance of Electrostatic Precipitators (ESP), the ESP comprising a
plurality of collecting electrodes and discharge electrodes disposed in a
space-apart relationship; an unidirectional high voltage is applicable in
between the electrodes with the collecting electrodes grounded; a
passage for routing dust laden flue gas from the boiler provided in the
ESP, the dust particles being electrically charged upon generation of an
ionizing field due to said high voltage leading to collection of dust particles
on the electrodes; a rapper mechanism for dislodging the accumulated
dust particles from the collector plates; and a support device for erection
and maintenance of the ESP, the support device supporting a lifting beam
holding an emitting frame including accessories, a lifting rod, and an
insulator, the support-device comprising a first subassembly consisting of
a lifting rod (09) having a threaded end, an a solid rod (08) welded at the
bottom of the lifting rod (09); and a second subassembly consisting of a
lifting beam (05) welded with a holding pipe (07) and strengthened by
welding a plurality of stiffeners (06), the second subassembly being
insertable through the bottom of the first subassembly and provided with
a bush (02) and at least one washer plate (03) being fixed by means of a
nut (04) having matching thread of said threaded end of the lifting rod
(09).
2. An improved device for supporting the emitting frame set during erection
and maintenance of Electrostatic Precipitators as substantially described
and Illustrated herein with reference to the accompanying drawings.

ABSTRACT

An improved device for supporting the emitting frame set during erection and
maintenance of Electrostatic Precipitators (ESP), the ESP comprising a plurality of
collecting electrodes and discharge electrodes disposed in a space-apart
relationship; an unidirectional high voltage is applicable in between the
electrodes with the collecting electrodes grounded; a passage for routing dust
laden flue gas from the boiler provided in the ESP, the dust particles being
electrically charged upon generation of an ionizing field due to said high voltage
leading to collection of dust particles on the electrodes; a rapper mechanism for
dislodging the accumulated dust particles from the collector plates; and a
support device for erection and maintenance of the ESP, the support device
supporting a lifting beam holding an emitting frame including accessories, a
lifting rod, and an insulator, the support-device comprising a first subassembly
consisting of a lifting rod (09) having a threaded end, an a solid rod (08) welded
at the bottom of the lifting rod (09); and a second subassembly consisting of a
lifting beam (05) welded with a holding pipe (07) and strengthened by welding a
plurality of stiffeners (06), the second subassembly being insertable through the
bottom of the first subassembly and provided with a bush (02) and at least one
washer plate (03) being fixed by means of a nut (04) having matching thread of
said threaded end of the lifting rod (09).