Title of Invention	A DEVICE FOR WATER-LEVEL CONTROL IN HIGH PRESSURE HEATERS OF PROCESS STEAM GENERATION PLANTS
Abstract	This invention relates to a device for water-level control in high pressure heaters in process steam generation plants in particular thermal plants, comprising; a closed chamber (2,3) with the inside wall having a ceramic insulator (2) and the outside wall constituting a steel tube (3), the ceramic insulator (2) being sealed inside the steel tube (3) by means of a plurality of ferrules (8); a plurality of spring means (9) disposed around the ferrules (8) to enable the spring means (9) to continually apply on activation a high force on the ferrules (8) to prevent leakage due to thermal cycling; at least one bellows (6) to compensate the difference in the coefficients of thermal expansion of the ceramic insulator (2) and the steel tube (3) leading to minimum transmission of the axial force on continuity apply on activation a heavy force on the fesvules to prevent leakage due to thermal cycling; at least one bellows (6) to compensate the difference in the coefficients of thermal expansion of the ceramic insulator (2) and the steel tube (3) leading to minimum transmission of the axial force on the ferrules (8); a main electrode (4) comprising a first electrode formed by a ceramic tube with s.s. foil disposed inside the insulator tube (2), and a second electrode formed by the steel (3) ground to earth; one each reference electrode (1,7) for steam and water connected to an electronic module, the ratio of capacitance of the reference electrodes (1,7) being adapted for calculation with the capacitance of the main electrode (4); and the electronic module for analyzing at least three capacitance data and generating signals to control the control valves.

Title of Invention

A DEVICE FOR WATER-LEVEL CONTROL IN HIGH PRESSURE HEATERS OF PROCESS STEAM GENERATION PLANTS

Abstract

This invention relates to a device for water-level control in high pressure heaters in process steam generation plants in particular thermal plants, comprising; a closed chamber (2,3) with the inside wall having a ceramic insulator (2) and the outside wall constituting a steel tube (3), the ceramic insulator (2) being sealed inside the steel tube (3) by means of a plurality of ferrules (8); a plurality of spring means (9) disposed around the ferrules (8) to enable the spring means (9) to continually apply on activation a high force on the ferrules (8) to prevent leakage due to thermal cycling; at least one bellows (6) to compensate the difference in the coefficients of thermal expansion of the ceramic insulator (2) and the steel tube (3) leading to minimum transmission of the axial force on continuity apply on activation a heavy force on the fesvules to prevent leakage due to thermal cycling; at least one bellows (6) to compensate the difference in the coefficients of thermal expansion of the ceramic insulator (2) and the steel tube (3) leading to minimum transmission of the axial force on the ferrules (8); a main electrode (4) comprising a first electrode formed by a ceramic tube with s.s. foil disposed inside the insulator tube (2), and a second electrode formed by the steel (3) ground to earth; one each reference electrode (1,7) for steam and water connected to an electronic module, the ratio of capacitance of the reference electrodes (1,7) being adapted for calculation with the capacitance of the main electrode (4); and the electronic module for analyzing at least three capacitance data and generating signals to control the control valves.

Full Text	2 FIELD OF INVENTION The invention relates to a device for continuous control and display of the level of water in a process steam generation plant where pressurized water and steam co-exists at high temperature. BACKGROUND OF INVENTION Presently the level of water in a process steam generation plant is measured using differential pressure, time taken for sound or electromagnetic wave to reflect from the junction of steam and water. One of the methods to measure the water level is to measure the height of water column using differential pressure sensors. However, the differential pressure created by the change in the height of water level is very small. When this happens in a highly pressurized vessel, the ability of the pressure transducer to resolve this differential pressure is significantly reduced. Another method for measuring the level of water is by the time taken by a sound wave to travel from the source to the junction of steam and water. The sound can travel in steam or metal wire. In this device there are difficulties of isolating the sensors from the heat. If the medium is steam then the velocity of sound significantly changes due to temperature and pressure. Thus there are always significant errors as most of the available instruments cannot compensate for the 3 temperature and pressure changes. Where, a wire is used for transmission of sound, a magnetic float is used to identify the steam and water junction. In this type of devices, the magnet loses its magnetism when operating at high temperature. The radar type devices for measuring the level of water uses the time taken for the electromagnetic waves to reflect from the surface of the water and steam junction. This again has the difficulty of isolating the transmitter from heat. Moreover, for most of the prior art devices, the response time is 0.7 to 1 second, which is substantially slow for the control of water level in the thermal power plant, in particular in a process steam generation plant. OBJECTS OF THE INVENTION It is therefore an object of the invention to propose a device for water level control in high pressure heaters in process steam generation plants, in particular thermal power plant. Another object of the invention is to propose a device for water level control in high pressure heaters in process steam generation plants, in particular thermal power plant, which is capable of operating at subcritical temperatures and pressures of water. 4 A further object of the invention is to propose a device for water level control in high pressure heaters in process steam generation plants, in particular thermal power plant, which does not have any moving component enabling to sustain longer operational life. A still further object of the invention is to propose a device for water level control in high pressure heaters in process steam generation plants, in particular thermal power plant, which is simple and cost-effective. SUMMARY OF INVENTION According to the invention, the device is designed to measure the level of water and steam in a high temperature and pressure environment prevailing in a thermal power plant. This level of water and steam is then compared with the set values and an electrical output signal is generated for the control of the valves necessary to maintain the water level in a pressurised vessel. A visual display is provided in respect of the level of water and steam at the place of operation. A scheme connectivity of various plant control systems with different technologies, is proposed. Using the connectivity scheme the display may be provided to the plant control systems located remotely. The invention thus enables water level control in the high pressure heaters of a thermal power plant. The device is designed to operate at sub critical temperatures and pressures of water. The water has very high dielectric constant when compared to steam. But as the density of water and steam changes, the 5 dielectric constant changes. The ratio of dielectric constant of water and steam approaches unity as the steam reaches critical point. The device uses no moving part and all parts have the capability to sustain the temperature and pressure encountered in a steam power plant continuously. The sensed level is compared with the three set points and a preferred proportionate signal is generated for the feed water bypass system. The device is capable of being set from a computer and also generates signal for the different types of communication and hard ware for the plant control system. The device displays the level of the water locally using Vh digit 7 segment LED display. For communication to other systems and computers, the communication is achieved by Ethernet, RS232, RS 485, Modbus protocols. This communication is used for setting and calibration of the device and for the remote display. The rate of change of water level is analysed and correspondingly the output signal is generated for the control valves, to maintain the water level at set points. Three set points are used for the control of there separate control valves. Three outputs are available as 4 - 20mA signals. These outputs are also available on the digital communication channels. A high level signal is generated for the feed water bypass system. The device can be calibrated and set to different water levels for operation, by the use of the computer. 6 The device is capable of sensing the change of level in 0.015 seconds and generate new results for the output control signals in less than 0.075 seconds. This speed is required as many of the processes in a thermal power plant are very fast. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Fig. 1 - shows a schematic of the device according to the invention. Fig. 2 - shows the schematic for the electronics incorporated in the device of the invention. DETAILED DESCRIPTION OF INVENTION In configuration of the device, the invention adapts the known scientific principle for example, when two electrodes are separated by dielectric medium, a capacitor is formed. If the dielectric medium is liquid and its level between the plates vary, the capacitance also varies proportionately. On calibration of the capacitance to the level of the fluid, the device becomes a level measurement device. As shown in figure - 1, the device is built around a sintered Alumina tube (2). This tube (2) is placed inside a stainless steel tube (3). The stainless steel tube (3) is sealed with the Alumina tube (2) using special type of copper ferrule (8). This makes a closed chamber with the inside wall having a ceramic 7 insulator and on the outside, a steel tube. Due the thermal cycling there are possibilities that the ferrule (8) will start leaking. This possibility has been taken care by providing a plurality of springs (9) which constantly apply a heavy force on the ferrule (8), keeping it tight over the Alumina tube (2). There is a difference in the coefficient of thermal expansion of the alumina tube (2) and the stainless steel tube (3). This has been compensated by using at least one bellows (6), so that a very little axial force is transmitted on the ferrule (8) due to differential thermal expansion. Inside the Alumina tube (2), another ceramic tube is placed, over which SS foil is wrapped. This serves as a second electrode (4), the first being the stainless steel tube (3), ground to the earth of the electronics. As the pressure and temperature vary during the operation, the dielectric properties of water and steam consequently vary. Hence, for the measurement of capacitance, two reference electrodes (1,7) of ten mm length are created. The ratio of capacitance of these reference electrode (1,7) are connected by wires to the electronic circuits placed in a separate box. The steam and water inlet are connected to the stainless steel tube (3) by a half circle tube (5). This half circle tube (5) absorbs all the stresses caused by differential thermal expansion of the casing, fittings and the main Stainless steel tube (3). 8 As shown in figure - 2, the capacitance is measured by the time taken for charging and discharging the capacitor between two fixed voltages. Similarly the time is measured for charging and discharging of the capacitance formed by the reference electrodes (1,7). These three timings are analysed in a microcontroller to generate signals for controlling the three control valves (not shown). Depending upon the rate of rise or fall of water level, the corresponding digital signal is derived for modulating the control valve. The digital signal is further converted to 4 - 20mA signal for controlling the valves. A microcontroller generates output for local LED display of the level. To make the device compatible with the different standards of plant control system, outputs for RS 232, RS 484, Ethernet and modbus communication protocols are generated. These signals make the remote display possible. The device is capable of being calibrated and set with laptop or computer. If the reference electrode meant for steam (7) is covered with the water then the ratio of dielectric constant is one and value of capacitance of individual electrodes (1,7) is high. Similarly if the reference electrode for the water (1), is in steam then also the ratio of dielectric constant is one and value of capacitance of individual electrodes is low. By these values the microcontroller can determine the high and low level of the water level, ie when the water and steam are beyond the range of the device. 9 WE CLAIM 1. A device for water-level control in high pressure heaters in process steam generation plants in particular thermal plants, comprising : - a closed chamber (2,3) with the inside wall having a ceramic insulator (2) and the outside wall constituting a steel tube (3), the ceramic insulator (2) being sealed inside the steel tube (3) by means of a plurality of ferrules (8); - a plurality of spring means (9) disposed around the ferrules (8) to enable the spring means (9) to continually apply on activation a high force on the ferrules (8) to prevent leakage due to thermal cycling; - at least one bellows (6) to compensate the difference in the coefficients of thermal expansion of the ceramic insulator (2) and the steel tube (3) leading to minimum transmission of the axial force on continuity apply on activation a heavy force on the fesvules to prevent leakage due to thermal cycling; - at least one bellows (6) to compensate the difference in the coefficients of thermal expansion of the ceramic insulator (2) and the steel tube (3) leading to minimum transmission of the axial force on the ferrules (8); 19 - a main electrode (4) comprising a first electrode formed by a ceramic tube with s.s. foil disposed inside the insulator tube (2), and a second electrode formed by the steel (3) ground to earth; - one each reference electrode (1,7) for steam and water connected to an electronic module, the ratio of capacitance of the reference electrodes (1,7) being adapted for calculation with the capacitance of the main electrode (4); and - the electronic module for analyzing at least three capacitance data and generating signals to control the control valves. 2. The device as claimed in claim 1, wherein the steam and water inlets are connected to the steel tube (3) by a half-circle tube (5). 3. The device as claimed in claim 1, wherein the three capacitance data represent the time taken for charging and discharging a capacitor disposed between two fixed voltage, and the time taken for charging and discharging each reference electrodes (1,7). 4. The device as claimed in claim 1 or 2, wherein the digital signals representing the rate of rise or fall of water level transmitted by the microcontroller is converted to 4 - 20 mA signal for adaptation in controlling the control valves. 11# 5. The device as claimed in claims 1 or 4 or 5, wherein the device is enabled to communicate in Ethernet and modbus protocols to commensenrate with the communication protocols of different plant systems. 6. The device as claimed in claim l, wherein the microcontroller enables local LED display of the water level including remote display. 7. A device for water-level control in high pressure heaters in process steam generation plants in particular thermal plants, as substantially described herein with reference to the accompanying drawings. Dated this 24th day of March, 2008 This invention relates to a device for water-level control in high pressure heaters in process steam generation plants in particular thermal plants, comprising; a closed chamber (2,3) with the inside wall having a ceramic insulator (2) and the outside wall constituting a steel tube (3), the ceramic insulator (2) being sealed inside the steel tube (3) by means of a plurality of ferrules (8); a plurality of spring means (9) disposed around the ferrules (8) to enable the spring means (9) to continually apply on activation a high force on the ferrules (8) to prevent leakage due to thermal cycling; at least one bellows (6) to compensate the difference in the coefficients of thermal expansion of the ceramic insulator (2) and the steel tube (3) leading to minimum transmission of the axial force on continuity apply on activation a heavy force on the fesvules to prevent leakage due to thermal cycling; at least one bellows (6) to compensate the difference in the coefficients of thermal expansion of the ceramic insulator (2) and the steel tube (3) leading to minimum transmission of the axial force on the ferrules (8); a main electrode (4) comprising a first electrode formed by a ceramic tube with s.s. foil disposed inside the insulator tube (2), and a second electrode formed by the steel (3) ground to earth; one each reference electrode (1,7) for steam and water connected to an electronic module, the ratio of capacitance of the reference electrodes (1,7) being adapted for calculation with the capacitance of the main electrode (4); and the electronic module for analyzing at least three capacitance data and generating signals to control the control valves.

Full Text

2
FIELD OF INVENTION
The invention relates to a device for continuous control and display of the level
of water in a process steam generation plant where pressurized water and steam
co-exists at high temperature.
BACKGROUND OF INVENTION
Presently the level of water in a process steam generation plant is measured
using differential pressure, time taken for sound or electromagnetic wave to
reflect from the junction of steam and water.
One of the methods to measure the water level is to measure the height of water
column using differential pressure sensors. However, the differential pressure
created by the change in the height of water level is very small. When this
happens in a highly pressurized vessel, the ability of the pressure transducer to
resolve this differential pressure is significantly reduced.
Another method for measuring the level of water is by the time taken by a sound
wave to travel from the source to the junction of steam and water. The sound
can travel in steam or metal wire. In this device there are difficulties of isolating
the sensors from the heat. If the medium is steam then the velocity of sound
significantly changes due to temperature and pressure. Thus there are always
significant errors as most of the available instruments cannot compensate for the

3
temperature and pressure changes. Where, a wire is used for transmission of
sound, a magnetic float is used to identify the steam and water junction. In this
type of devices, the magnet loses its magnetism when operating at high
temperature.
The radar type devices for measuring the level of water uses the time taken for
the electromagnetic waves to reflect from the surface of the water and steam
junction. This again has the difficulty of isolating the transmitter from heat.
Moreover, for most of the prior art devices, the response time is 0.7 to 1 second,
which is substantially slow for the control of water level in the thermal power
plant, in particular in a process steam generation plant.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a device for water level
control in high pressure heaters in process steam generation plants, in particular
thermal power plant.
Another object of the invention is to propose a device for water level control in
high pressure heaters in process steam generation plants, in particular thermal
power plant, which is capable of operating at subcritical temperatures and
pressures of water.

4
A further object of the invention is to propose a device for water level control in
high pressure heaters in process steam generation plants, in particular thermal
power plant, which does not have any moving component enabling to sustain
longer operational life.
A still further object of the invention is to propose a device for water level control
in high pressure heaters in process steam generation plants, in particular thermal
power plant, which is simple and cost-effective.
SUMMARY OF INVENTION
According to the invention, the device is designed to measure the level of water
and steam in a high temperature and pressure environment prevailing in a
thermal power plant. This level of water and steam is then compared with the
set values and an electrical output signal is generated for the control of the
valves necessary to maintain the water level in a pressurised vessel. A visual
display is provided in respect of the level of water and steam at the place of
operation. A scheme connectivity of various plant control systems with different
technologies, is proposed. Using the connectivity scheme the display may be
provided to the plant control systems located remotely.
The invention thus enables water level control in the high pressure heaters of a
thermal power plant. The device is designed to operate at sub critical
temperatures and pressures of water. The water has very high dielectric constant
when compared to steam. But as the density of water and steam changes, the

5
dielectric constant changes. The ratio of dielectric constant of water and steam
approaches unity as the steam reaches critical point.
The device uses no moving part and all parts have the capability to sustain the
temperature and pressure encountered in a steam power plant continuously.
The sensed level is compared with the three set points and a preferred
proportionate signal is generated for the feed water bypass system. The device is
capable of being set from a computer and also generates signal for the different
types of communication and hard ware for the plant control system.
The device displays the level of the water locally using Vh digit 7 segment LED
display. For communication to other systems and computers, the communication
is achieved by Ethernet, RS232, RS 485, Modbus protocols. This communication
is used for setting and calibration of the device and for the remote display.
The rate of change of water level is analysed and correspondingly the output
signal is generated for the control valves, to maintain the water level at set
points. Three set points are used for the control of there separate control valves.
Three outputs are available as 4 - 20mA signals. These outputs are also
available on the digital communication channels. A high level signal is generated
for the feed water bypass system.
The device can be calibrated and set to different water levels for operation, by
the use of the computer.

6
The device is capable of sensing the change of level in 0.015 seconds and
generate new results for the output control signals in less than 0.075 seconds.
This speed is required as many of the processes in a thermal power plant are
very fast.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig. 1 - shows a schematic of the device according to the invention.
Fig. 2 - shows the schematic for the electronics incorporated in the device of the
invention.
DETAILED DESCRIPTION OF INVENTION
In configuration of the device, the invention adapts the known scientific principle
for example, when two electrodes are separated by dielectric medium, a
capacitor is formed. If the dielectric medium is liquid and its level between the
plates vary, the capacitance also varies proportionately. On calibration of the
capacitance to the level of the fluid, the device becomes a level measurement
device.
As shown in figure - 1, the device is built around a sintered Alumina tube (2).
This tube (2) is placed inside a stainless steel tube (3). The stainless steel tube
(3) is sealed with the Alumina tube (2) using special type of copper ferrule (8).
This makes a closed chamber with the inside wall having a ceramic

7
insulator and on the outside, a steel tube. Due the thermal cycling there are
possibilities that the ferrule (8) will start leaking. This possibility has been taken
care by providing a plurality of springs (9) which constantly apply a heavy force
on the ferrule (8), keeping it tight over the Alumina tube (2).
There is a difference in the coefficient of thermal expansion of the alumina tube
(2) and the stainless steel tube (3). This has been compensated by using at least
one bellows (6), so that a very little axial force is transmitted on the ferrule (8)
due to differential thermal expansion.
Inside the Alumina tube (2), another ceramic tube is placed, over which SS foil is
wrapped. This serves as a second electrode (4), the first being the stainless steel
tube (3), ground to the earth of the electronics. As the pressure and temperature
vary during the operation, the dielectric properties of water and steam
consequently vary. Hence, for the measurement of capacitance, two reference
electrodes (1,7) of ten mm length are created. The ratio of capacitance of these
reference electrode (1,7) are connected by wires to the electronic circuits placed
in a separate box.
The steam and water inlet are connected to the stainless steel tube (3) by a half
circle tube (5). This half circle tube (5) absorbs all the stresses caused by
differential thermal expansion of the casing, fittings and the main Stainless steel
tube (3).

8
As shown in figure - 2, the capacitance is measured by the time taken for
charging and discharging the capacitor between two fixed voltages. Similarly the
time is measured for charging and discharging of the capacitance formed by the
reference electrodes (1,7). These three timings are analysed in a microcontroller
to generate signals for controlling the three control valves (not shown).
Depending upon the rate of rise or fall of water level, the corresponding digital
signal is derived for modulating the control valve. The digital signal is further
converted to 4 - 20mA signal for controlling the valves. A microcontroller
generates output for local LED display of the level. To make the device
compatible with the different standards of plant control system, outputs for RS
232, RS 484, Ethernet and modbus communication protocols are generated.
These signals make the remote display possible. The device is capable of being
calibrated and set with laptop or computer.
If the reference electrode meant for steam (7) is covered with the water then
the ratio of dielectric constant is one and value of capacitance of individual
electrodes (1,7) is high. Similarly if the reference electrode for the water (1), is
in steam then also the ratio of dielectric constant is one and value of capacitance
of individual electrodes is low. By these values the microcontroller can determine
the high and low level of the water level, ie when the water and steam are
beyond the range of the device.

9
WE CLAIM
1. A device for water-level control in high pressure heaters in process steam
generation plants in particular thermal plants, comprising :
- a closed chamber (2,3) with the inside wall having a ceramic
insulator (2) and the outside wall constituting a steel tube (3), the
ceramic insulator (2) being sealed inside the steel tube (3) by
means of a plurality of ferrules (8);
- a plurality of spring means (9) disposed around the ferrules (8) to
enable the spring means (9) to continually apply on activation a
high force on the ferrules (8) to prevent leakage due to thermal
cycling;
- at least one bellows (6) to compensate the difference in the
coefficients of thermal expansion of the ceramic insulator (2) and
the steel tube (3) leading to minimum transmission of the axial
force on continuity apply on activation a heavy force on the
fesvules to prevent leakage due to thermal cycling;
- at least one bellows (6) to compensate the difference in the
coefficients of thermal expansion of the ceramic insulator (2) and
the steel tube (3) leading to minimum transmission of the axial
force on the ferrules (8);

19
- a main electrode (4) comprising a first electrode formed by a
ceramic tube with s.s. foil disposed inside the insulator tube (2),
and a second electrode formed by the steel (3) ground to earth;
- one each reference electrode (1,7) for steam and water connected
to an electronic module, the ratio of capacitance of the reference
electrodes (1,7) being adapted for calculation with the capacitance
of the main electrode (4); and
- the electronic module for analyzing at least three capacitance data
and generating signals to control the control valves.

2. The device as claimed in claim 1, wherein the steam and water inlets are
connected to the steel tube (3) by a half-circle tube (5).
3. The device as claimed in claim 1, wherein the three capacitance data
represent the time taken for charging and discharging a capacitor
disposed between two fixed voltage, and the time taken for charging and
discharging each reference electrodes (1,7).
4. The device as claimed in claim 1 or 2, wherein the digital signals
representing the rate of rise or fall of water level transmitted by the
microcontroller is converted to 4 - 20 mA signal for adaptation in
controlling the control valves.

11#
5. The device as claimed in claims 1 or 4 or 5, wherein the device is enabled
to communicate in Ethernet and modbus protocols to commensenrate
with the communication protocols of different plant systems.
6. The device as claimed in claim l, wherein the microcontroller enables local
LED display of the water level including remote display.
7. A device for water-level control in high pressure heaters in process steam
generation plants in particular thermal plants, as substantially described
herein with reference to the accompanying drawings.
Dated this 24th day of March, 2008

This invention relates to a device for water-level control in high pressure heaters
in process steam generation plants in particular thermal plants, comprising; a
closed chamber (2,3) with the inside wall having a ceramic insulator (2) and the
outside wall constituting a steel tube (3), the ceramic insulator (2) being sealed
inside the steel tube (3) by means of a plurality of ferrules (8); a plurality of
spring means (9) disposed around the ferrules (8) to enable the spring means
(9) to continually apply on activation a high force on the ferrules (8) to prevent
leakage due to thermal cycling; at least one bellows (6) to compensate the
difference in the coefficients of thermal expansion of the ceramic insulator (2)
and the steel tube (3) leading to minimum transmission of the axial force on
continuity apply on activation a heavy force on the fesvules to prevent leakage
due to thermal cycling; at least one bellows (6) to compensate the difference in
the coefficients of thermal expansion of the ceramic insulator (2) and the steel
tube (3) leading to minimum transmission of the axial force on the ferrules (8); a
main electrode (4) comprising a first electrode formed by a ceramic tube with
s.s. foil disposed inside the insulator tube (2), and a second electrode formed by
the steel (3) ground to earth; one each reference electrode (1,7) for steam and
water connected to an electronic module, the ratio of capacitance of the
reference electrodes (1,7) being adapted for calculation with the capacitance of
the main electrode (4); and the electronic module for analyzing at least three
capacitance data and generating signals to control the control valves.

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Patent Number

271965

Indian Patent Application Number

589/KOL/2008

PG Journal Number

12/2016

Publication Date

18-Mar-2016

Grant Date

11-Mar-2016

Date of Filing

24-Mar-2008

Name of Patentee

BHARAT HEAVY ELECTRICALS LIMITED

Applicant Address

REGIONAL OPERATIONS DIVISION (ROD), PLOT NO. : 9/1, DJBLOCK 3RD FLOOR, KARUNAMOYEE, SALT LAKE CITY, KOLKATA-700091, HAVING ITS REGISTERED OFFICE AT BHEL HOUSE, SIRI FORT, NEW DELHI- 110049

Inventors:

#	Inventor's Name	Inventor's Address
1	A. K. GUPTA	THERMAL SYSTEM ENGINEERING DIVISION, BHARAT HEAVY ELECTRICALS LIMITED BHOPAL

PCT International Classification Number

G21C17/00; G21C17/08; G21C17/1

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA