|Title of Invention||
AN IMPROVED IGNITOR APPARATUS FOR ACHIEVING CONTROLLED SPARK RATE AND ENERGY IN A BOILER FURNACE
|Abstract||NO ABSTRACTThe invention is an ignitor system suitable for igniting different fuels such as technology with compact power pack for generating electrical sparks of varying energy level and rate. The system suitable for igniting different fuels requiring different ignition levels. The system by its nature of design is of reduced size . and weight and improved safety feature.|
|Full Text||FIELD OF INVENTION
The present invention relates to the field of efficient light up of liquid / gas fuels
fired In the furnace of a boiler and other simitar applications. In particular, the
present invention relates to employing a high frequency switching converter
technology to generate high voltage required for producing sparks at variable
energy levels and sparking rates suitable for different fuels. More particularly,
the present invention relates to using a high frequency operated step-up
transformer to reduce the size and weight of the ignition apparatus. The present
invention uses an electronically operated switch to control the sparking rate and
energy instead of a self-actuating spark gap conventionally used.
BACKGROUND OF THE INVENTION
Boilers are employed world-wide by thermal power plants, refineries and to many
other industries to produce steam for their operation. Many of the boilers are
designed for firing fuel oil and / or fuel gas as support fuel and / or load carrying
fuel. In all these boilers, suitable type of apparatus (ignitors) haye to be used to
light up the fuel in burners.
After ensuring proper conditions for firing the fuel, the fuel is admitted into the
furnace of the boiler. At the same time, electronic power supply is given to the
ignitors to produce sparks in the vicinity of burning zone. The fuel gets lighted
Up by the heat energy provided by me sparks. Igniting ftie fuel automatically in
the first attempt Itself is considered important in any boiler furnace. The heat
energy provided by the sparks from ignitors play an important role in this aspect.
This invention relates to an improved method of producing and controlling sparks
in electric ignitors.
EXISTING STATE OF ART
Presently available igniters work on the principle of producing high voltage in the
order of 4000 V from 230 V (or 110 V AC), charging capacitors to this high
voltage and discharging them with a suitable spark gap. The stored energy of
the capacitor is released in sparks. Conventionally designed igniters use a line
frequency operated step-up transformer, the secondary of which is connected to
a voltage doubler circuit and high voltage capacitors. A self closing, voltage
activated spark gap is used, to discharge the high voltage capacitor to produce
the sparks at the tip of the ignitor which ignite the fuels.
DISADVANTAGE OF THE EXISTING STATE OF ART
Since the high voltage circuitry employed in presently available igniters, are
operated with line frequency step-up transformer, the spark generator box is
heavy and bigger in size. The output of the spark generator box is connected to
a flexible rod assembly. The rod assembly is advanced into the furnace during
light-up of fuel and subsequently retracted after ignition. It is operated by a
pneumatic actuator. Due to its weight and size, the spark generator box cannot
be mounted on the actuator. Therefore the spark generator box is mounted
separately and the high voltage connection to the spark tip is given by a flexible
high voltage cable. The charge and discharge cycles of the capacitor is
controlled by the self-actuating spark gap. Over a period of few months of
operation, the spark gap due to aging and thermal effects do not produce
consistent sparks and the spark rate / energy level vary.
OBJECTIVES OF THE INVENTION
It is therefore, an object of the invention to achieve controlled spark energies
and sparking rate by employing an electronically controlled switching circuitry -
This enables the ignitor suitable for different types of fuels.
Another object of the invention is to reduce the size and weight of the apparatus
for quick erection / installation.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Figure 1 shows a schematic diagram of the Spark generator
according to the present invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
As shown in Figure 1, the apparatus comprises a spark generator with line
commutated rectifier (1) and a high frequency switching device (2) The output of
switching device is connected to a ferrite core step-up transformer (3) From the
secondary of the transformer high voltage DC is generated with the use of
HF/HV diodes (4). The high voltage DC thus produced charges a capacitor bank
(5). The discharge of the capacitor is controlled through an electronic controlled
switch (6), the output of which connected to the spark tip (7) which generate
sparks of controlled rate and energy suitable for different fuels.
|Indian Patent Application Number||1083/KOL/2005|
|PG Journal Number||07/2011|
|Date of Filing||28-Nov-2005|
|Name of Patentee||BHARAT HEAVY ELECTRICALS LIMITED|
|Applicant Address||REGIONAL OPERATIONS DIVISION (ROD), PLOT NO: 9/1, DJ BLOCK, 3RD FLOOR, KARUNAMOYEE, SALT LAKE CITY, KOLKATA - 700091, HAVIGN ITS REGISTERED OFFICE AT BHEL HOUSE, SIRI FORT, NEW DELHI-110049, INDIA|
|PCT International Classification Number||F23B|
|PCT International Application Number||N/A|
|PCT International Filing date|