| 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 |
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| 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 3 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 4 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. 5 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. 6 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). 7 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 8 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. 9 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. |
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00650-kol-2007-correspondence others 1.1.pdf
00650-kol-2007-correspondence others.pdf
00650-kol-2007-description complete.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-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-REPLY TO EXAMINATION REPORT.pdf
| Patent Number | 253112 | |||||||||
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| 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 | |||||||||
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| PCT International Classification Number | F22D1/32 | |||||||||
| PCT International Application Number | N/A | |||||||||
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