FIELD OF THE INVENTION
The present invention relates to a wireless interface device for controlling an
operably attached Electrostatic Precipitator and ash disposal system.
BACKGROUND OF THE INVENTION
Electrostatic precipitation is one of the most effective ways to control air
pollution generated by industrial emissions. This technique, which has proven
highly effective in controlling air pollution, has been used for removal of
undesirable particulate matter from a gas stream by electrostatic precipitation.
Electrostatic precipitator (hereinafter referred to as ESP) is an air pollution
control device designed to electrically charge and collect particulates generated
from industrial processes such as those occurring in power plants, cement plants,
pulp and paper, mills and utilities. The electrically charged particles are attracted
towards electrode plates, viz., discharge electrode and collection plate. ESP is
divided into a plurality of fields depending on the dust load. During the operation
of an electrostatic precipitator, the dust from collector plates and discharge
electrodes is periodically removed for further conveying of the collected dust to
ensure effective precipitation of dust.
The dust collected / deposited on the collecting electrodes and discharge
electrodes are removed using a rapping mechanism, and is collected in the
hoppers. For this purpose at least one rapping motor is used, which is powered
from an Auxiliary Control Panel (ACP) and controlled through a RAPPER
controller. The at least one Rapping motor can be switched ON and OFF from a
local pushbutton for maintenance purpose. Further, the collected dust is
periodically removed from the hopper using a ash handling system. Between the
intervals of periodical removals, the collected dust is retained in the hoppers.
During this period, the dust temperature is maintained above acid dew point
(90deg. C) to avoid solidification of ash and to ensure a free flow of the dust
during removal. For maintaining this surface temperature uniformly throughout
at least one-third of hopper wall surface, at least one hopper heater is used. The
at least one hopper heater is controlled using a thermostat. Once the hopper
temperature reaches the set value, the hopper heater is switched OFF and when
the hopper temperature goes below a set value, it is switched ON, from a local
junction box. An ash level indicator is used for monitoring the level of Ash
collected in the hopper.
In the prior art system, pushbuttons are used for controlling the rapping motor
which is connected to a Rapping motor starting module (in ACO). The thermostat
is used for controlling the Hopper heater which is connected to a Hopper heater
power supply module (in ACP). The ash level indicator is used for Ash level
monitoring and is connected to the Auxiliary control panel (ACP) using copper
cables. This involves several kilometers of cables routed through cable trays with
supports. This new invention avoids these cables routed through specially laid
cable trays and supports, thereby simplifying the erection and troubleshooting.
Also, it improves the aesthetic look of the plant and reduces fire hazards.
OBJECTS OF THE INVENTION
It is therefore an object of the invention is to eliminate connecting cables, cable
trays and supports by introducing wireless interface modules in an Electrostatic
precipitator (ESP) for controlling the Rapping motors, the hopper heater
thermostats, and the ash level indicators.
Another object of the invention is to simplify the erection procedure and existing
trouble shooting measures of an ESP operabiy connected to an ash - disposal
system.
SUMMARY OF THE INVENTION
Accordingly, there is provided a wireless interface device for controlling an
operabiy attached Electrostatic Precipitator and ash disposal system, the ESP
having a rapping mechanism to dislodge the accumulated dust from the
collecting and discharge electrodes, the rapping mechanism comprising a rapping
controller, and at least one rapping motor powered by an auxiliary control panel
(ACP), the at least one rapping motor being activated or deactivated by a
pushbutton, the dislodged ash from the ESP accumulated in a hopper which is
controllably heated by at least one heater during the intermittent period of
disposal by a ash disposal system, the improvement is characterized in that an
wireless device comprising a transmitter and a receiver is respectively disposed
on the rapping motor and the ACP, a plurality of wireless modules disposed on
the ESP such that activation or de-activation command for ash disposal between
the hopper and the ash disposal system is transmitted or received wirelessly to
eliminate laying of copper cables with supports. The invention further provides
repeater modules at strategic locations in the Electrostatic precipitator structure
for effective functioning of said wireless modules.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 - Shows a prior art ESP for 270 MW Boiler and key plan.
Figure 2(a) - Shows a prior art boiler system lay-out for controlling rapping
motors of ESP.
Figure 2(b) - Shows an wireless interface device for controlling an ESP including
the ash disposal system according to the invention.
Figure 3 - Shows a hardware block diagram of the invented wireless an interface
device for controlling an operably attached electrostatic precipitator and ash
disposal system.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
The present invention is described herein below with reference to figures as
described. In the prior art system, the control signals of the rapping motors are
transmitted to the ACP using wires as shown in Fig.2a. This involves laying of
huge quantities of cables in pre-fabricated cable trays erected in cable trustless /
trenches. In the proposed system, the control signals of the rapping motors are
connected to the ACP using wireless modules as shown in Fig.2b. For this
purpose, wireless transmitters are installed at the Rapping motor to transmit the
start / stop commands from the Pushbutton located near the Rapping motor.
And a wireless receiver is installed at the ACP end, which receives the start / stop
commands and operates the contactors in the ACP for starting / stopping the
Rapping Motor.
In a similar manner, additional wireless modules are used for transmitting and
receiving thermostat signals for hopper heater controls, ash level signals (high)
and ash level signals (low).
The following are the advantages of the proposed invention:
1. Elimination of copper wires, cable trays and supports.
2. Ease of erection and troubleshooting.
3. Cycle time Reduction.
WE CLAIM
1. A wireless interface device for controlling an operably attached
Electrostatic Precipitator and ash disposal system, the ESP having a
rapping mechanism to dislodge the accumulated dust from the collecting
and discharge electrodes, the rapping mechanism companying a rapping
controller, and at least one rapping motor powered by an auxiliary control
panel (ACP), the at least one rapping motor being activated or deactivated
by a pushbutton, the dislodged ash from the ESP is accumulated in a
hopper which is controllably heated by at least one heater during the
intermittent period of disposal by an ash disposal system, the
improvement is characterized in that an wireless device comprising a
transmitter and a receiver is respectively disposed on the rapping motor
and the ACP, a plurality of wireless modules disposed on the ESP such
that activation or de-activation command for ash disposal between the
hopper and the ash disposal system is transmitted or received wirelessly
to eliminate the laying of copper cables with supports.
2. A wireless interface device for controlling an operably attached
Electrostatic Precipitator and ash disposal system as substantially
descended herein with reference to the accompanying drawings.

ABSTRACT

The invention relates to a wireless interface device for controlling an operably
attached Electrostatic Precipitator and ash disposal system, the ESP having a
rapping mechanism to dislodge the accumulated dust from the collecting and
discharge electrodes, the rapping mechanism companying a rapping controller,
and at least one rapping motor powered by an auxiliary control panel (ACP), the
at least one rapping motor being activated or deactivated by a pushbutton, the
dislodged ash from the ESP is accumulated in a hopper which is controllably
heated by at least one heater during the intermittent period of disposal by an
ash disposal system, the improvement is characterized in that an wireless device
comprising a transmitter and a receiver is respectively disposed on the rapping
motor and the ACP, a plurality of wireless modules disposed on the ESP such
that activation or de-activation command for ash disposal between the hopper
and the ash disposal system is transmitted or received wirelessly to eliminate the
laying of copper cables with supports.