Title of Invention

EFFICIENT AND IMPROVED PASS PARTITION PLATE ARRANGEMENT FOR SEPARATING HOT AND COLD FEED WATER IN FEED WATER HEATERS IN THERMAL POWER PLANTS

Abstract The problem arises in the prior Art was investigated and it was observed that the notches provided in the pass plate was the main cause for mixing of hot and cold feedwater. New Improved method comprising the partition plate is fitted into hemihead of high pressure feed water heater. While assembling it is also welded to the tube sheet. Initially, one strip of partition is welded to the tube sheet. Then, another curve plate, with the curvature matching with the profile of hemihead is kept in position, located property and then welded to the strip and sealing of partition plate is ensured. All these welds are lested for liquid penetrant leak lest and kerosene leak test. This ensures soundness of welding of Partition plate. The "C" seam welding of Hemihead to tube sheet is totally checked up by 100% RT & UT. This will ensure soundness of welding joint between hemihead and tube sheet. Secondly the leakage through the ligament was mainly due to erosion corrosion based on investigation of damaged pass partition plate, different shapes and configurations of man-way covers were studied and it was decided to increase the ligament on the cover plate of manhole on pass partition plate for efficient sealing of manhole. This arrangement ensures prevention of mixing of hot and cold feedwater.
Full Text 2
Field of the invention:
The present invention relates to an efficient and improved pass partition
Plate adaptable to feedwater heaters in thermal power plant.
Background of the invention:
A Feedwater heater is a power plant component used to pre-heat
feedwater delivered to the boiler.. Closed feedwater heaters are typically
shell and tube heat exchangers where the feedwater passes through the
tubes and is heated by turbine extraction steam. Feedwater flows through
the tubes in two passes where as steam flows on shell side in one pass.
Due to high design pressure, front channel header is made as
hemispherical head with a pass partition plate. Manholes are provided on
both hemispherical head and pass partition plate for maintenance work.
In order to facilitate 100% Radiography Testing (Non Destructive Testing)
of the weld joint between hemispherical head and Tubesheet, two notches

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are provided at the corners of pass partition plate as shown in fig. 1. After
NDT, these two notches are closed by welding with the closing plates.
This arrangement is causing Mixing of hot feed water with cold feedwater
mainly due to following two reasons:
1. Due to lack of sufficient accessibility, closing of notches is not done
roperly, which results in leakage.
2. Manhole on pass partition plate leaks due to lack of sufficient
ligament on the cover of manhole.
Whenever the poorly welded notches and the manhole on pass partition
plate leaks, the hot feedwater mixes up with cold feedwater thus reducing
the efficiency of heating feedwater. This mixing of feedwater results in
dropping of temperature at the outlet of feedwater. This loss of heating is
made up in the boiler by burning more coal. This reduces the thermal
efficiency of the feed water system. Drop in feedwater outlet temperature

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necessitates maintenance of the Feedwater Heater which includes re-
welding at the notch locations and tightening of manhole cover. This
process requires 36-hour shutdown. This kind of shutdown causes huge
loss of power generation.
OBJECTS OF THE INVENTION:
It is therefore, an object of the present invention to propose an improved
partition plate adaptable to feedwater heaters in thermal power plant
which eliminates the disadvantages of prior Art.
Another object of the present invention is to propose an improved partition
plate adaptable to feedwater heaters in thermal power plant which
prevents the mixing of hot and cold feedwater.
A further object of the present invention is to propose an improved
partition plate adaptable to feedwater heaters in thermal power plant
which provides efficient heating in feedwater heaters.

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A still further objects of the present invention is to propose an improved
partition plate adaptable to feedwater heaters in thermal power plant
which eliminates totally shut down due to pass partition plate failure.
Summary of the invention:
The problem arises in the prior Art was investigated and it was observed
that the notches provided in the pass plate was the main cause for mixing
of hot and cold feedwater. New Improved method comprising the partition
plate is fitted into hemihead of high pressure feed water heater. While
assembling it is also welded to the tube sheet. Initially, one strip of
partition is welded to the tube sheet. Then, another curve plate, with the
curvature matching with the profile of hemihead is kept in position, located
property and then welded to the strip and sealing of partition plate is
ensured. All these welds are lested for liquid penetrant leak lest and
kerosene leak test. This ensures soundness of welding of Partition plate.
The 'C' seam welding of Hemihead to tube sheet is totally checked up by
100% RT & UT. This will ensure soundness of welding joint between
hemihead and tube sheet.

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Secondly the leakage through the ligament was mainly due to erosion
corrosion based on investigation of damaged pass partition plate, different
shapes and configurations of man-way covers were studied and it was
decided to increase the ligament on the cover plate of manhole on pass
partition plate for efficient sealing of manhole. This arrangement ensures
prevention of mixing of hot and cold feedwater.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING:
Fig:-1. Shows a schematic view of a pass partition plate in prior Art.
Fig:- 2. Shows a schematic view of a partition plate according to new
invention.
DETAILS DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION:
As shown in Fig:- 2 the notches (8) provided in the hemi spherical shapped
pass partition plate (1) was eliminated by making a UT (9) for non-
destructive testing. More ligament (6) is also provided on manhole cover
plate (10).

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KEY FEATURE:
ReferenceCharacter Feature Figure
1. Pass Partition Plate 1,2
2. Expansion joint 1,2
3. Cover Nut 1,2
4. Cover Stud 1
5. Handle of manhole cover 1,2
6. Gasget for manhole cover 1
7. End cover 1,2
8. Notch plate to permit
radiography of closing
unit after radiography
notch is to be filed 1
9. Notch deleted by doing
UT at notch location 2
10. Manhole cover

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WE CLAIM:
1. An improved and heat efficient pass partition plate adoptable to
feedwater heater in thermal power plant comprises:-
• a hemi-spherical shaped plate with an UT at the edges for
joining with mother part and
• the plate was undergone for welding followed by non-
destructive testing at the joining point to prevent breakage of
hot and cold feedwater.
1. The pass partition plate as claimed in claim 1 where in mixing
of hot and cold feedwater are prevented by providing an
additional ligament on manhole cover plate for sealing.
2. The pass partition plate as claimed in claim 1, wherein the
material of pollution can be used as high temperature
resistance carbon steel.

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3. An improved and heat efficient pass partition plate adoptable to
feedwater heater in thermal power plant as substantially
deserved and illustrated herein with reference to accompanying
drawings.
Dated this 27th day of APRIL 2007

The problem arises in the prior Art was investigated and it was observed
that the notches provided in the pass plate was the main cause for mixing
of hot and cold feedwater. New Improved method comprising the partition
plate is fitted into hemihead of high pressure feed water heater. While
assembling it is also welded to the tube sheet. Initially, one strip of
partition is welded to the tube sheet. Then, another curve plate, with the
curvature matching with the profile of hemihead is kept in position, located
property and then welded to the strip and sealing of partition plate is
ensured. All these welds are lested for liquid penetrant leak lest and
kerosene leak test. This ensures soundness of welding of Partition plate.
The 'C' seam welding of Hemihead to tube sheet is totally checked up by
100% RT & UT. This will ensure soundness of welding joint between
hemihead and tube sheet. Secondly the leakage through the ligament was mainly due to erosion
corrosion based on investigation of damaged pass partition plate, different
shapes and configurations of man-way covers were studied and it was
decided to increase the ligament on the cover plate of manhole on pass
partition plate for efficient sealing of manhole. This arrangement ensures
prevention of mixing of hot and cold feedwater.

Documents:

00650-kol-2007-abstract.pdf

00650-kol-2007-claims.pdf

00650-kol-2007-correspondence others 1.1.pdf

00650-kol-2007-correspondence others.pdf

00650-kol-2007-description complete.pdf

00650-kol-2007-drawings.pdf

00650-kol-2007-form 1.pdf

00650-kol-2007-form 18.pdf

00650-kol-2007-form 2.pdf

00650-kol-2007-form 3.pdf

00650-kol-2007-gpa.pdf

650-KOL-2007-(02-04-2012)-ABSTRACT.pdf

650-KOL-2007-(02-04-2012)-AMANDED CLAIMS.pdf

650-KOL-2007-(02-04-2012)-AMANDED PAGES OF SPECIFICATION.pdf

650-KOL-2007-(02-04-2012)-CORRESPONDENCE.pdf

650-KOL-2007-(02-04-2012)-DRAWINGS.pdf

650-KOL-2007-(02-04-2012)-FORM-1.pdf

650-KOL-2007-(02-04-2012)-FORM-13.pdf

650-KOL-2007-(02-04-2012)-FORM-2.pdf

650-KOL-2007-(04-07-2012)-CORRESPONDENCE.pdf

650-KOL-2007-(27-12-2011)-ABSTRACT.pdf

650-KOL-2007-(27-12-2011)-CLAIMS.pdf

650-KOL-2007-(27-12-2011)-DESCRIPTION (COMPLETE).pdf

650-KOL-2007-(27-12-2011)-DRAWINGS.pdf

650-KOL-2007-(27-12-2011)-EXAMINATION REPORT REPLY RECIEVED.PDF

650-KOL-2007-(27-12-2011)-FORM-1.pdf

650-KOL-2007-(27-12-2011)-FORM-2.pdf

650-KOL-2007-(27-12-2011)-FORM-3.pdf

650-KOL-2007-(27-12-2011)-OTHERS.pdf

650-KOL-2007-CORRESPONDENCE.pdf

650-KOL-2007-EXAMINATION REPORT.pdf

650-KOL-2007-FORM 13.pdf

650-KOL-2007-FORM 18.pdf

650-KOL-2007-FORM 3.pdf

650-KOL-2007-FORM 5.pdf

650-KOL-2007-GPA.pdf

650-KOL-2007-GRANTED-ABSTRACT.pdf

650-KOL-2007-GRANTED-CLAIMS.pdf

650-KOL-2007-GRANTED-DESCRIPTION (COMPLETE).pdf

650-KOL-2007-GRANTED-DRAWINGS.pdf

650-KOL-2007-GRANTED-FORM 1.pdf

650-KOL-2007-GRANTED-FORM 2.pdf

650-KOL-2007-GRANTED-LETTER PATENT.pdf

650-KOL-2007-GRANTED-SPECIFICATION.pdf

650-KOL-2007-OTHERS.pdf

650-KOL-2007-REPLY TO EXAMINATION REPORT.pdf


Patent Number 253112
Indian Patent Application Number 650/KOL/2007
PG Journal Number 26/2012
Publication Date 29-Jun-2012
Grant Date 26-Jun-2012
Date of Filing 27-Apr-2007
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, HAVING ITS REGISTERED OFFICE AT BHEL HOUSE, SIRI FORT, NEW DELHI-110049
Inventors:
# Inventor's Name Inventor's Address
1 BANDELA SRINIVAS 2ND FLOOR, 02 ANNEXE, BHEL, R.C.PURAM, HYDERABAD - 502032
2 VENKITASUBBAN CHIDAMBARA KRISHNAN 2ND FLOOR, 02 ANNEXE, BHEL, R.C.PURAM, HYDERABAD - 502032
PCT International Classification Number F22D1/32
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA