US3729797A - Temporary support lug system on hanger tubes for erection of pressure parts - Google Patents

Temporary support lug system on hanger tubes for erection of pressure parts Download PDF

Info

Publication number
US3729797A
US3729797A US00152320A US3729797DA US3729797A US 3729797 A US3729797 A US 3729797A US 00152320 A US00152320 A US 00152320A US 3729797D A US3729797D A US 3729797DA US 3729797 A US3729797 A US 3729797A
Authority
US
United States
Prior art keywords
cylindrical members
tubes
support lug
tube
collar
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00152320A
Inventor
A Ambrose
H Nelson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Combustion Engineering Inc
Original Assignee
Combustion Engineering Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Combustion Engineering Inc filed Critical Combustion Engineering Inc
Application granted granted Critical
Publication of US3729797A publication Critical patent/US3729797A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K37/00—Auxiliary devices or processes, not specially adapted to a procedure covered by only one of the preceding main groups
    • B23K37/04—Auxiliary devices or processes, not specially adapted to a procedure covered by only one of the preceding main groups for holding or positioning work
    • B23K37/053—Auxiliary devices or processes, not specially adapted to a procedure covered by only one of the preceding main groups for holding or positioning work aligning cylindrical work; Clamping devices therefor
    • B23K37/0533—Auxiliary devices or processes, not specially adapted to a procedure covered by only one of the preceding main groups for holding or positioning work aligning cylindrical work; Clamping devices therefor external pipe alignment clamps
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/53—Means to assemble or disassemble
    • Y10T29/53113—Heat exchanger
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/53—Means to assemble or disassemble
    • Y10T29/53909—Means comprising hand manipulatable tool
    • Y10T29/53913—Aligner or center
    • Y10T29/53917—Tube with tube
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/53—Means to assemble or disassemble
    • Y10T29/53978—Means to assemble or disassemble including means to relatively position plural work parts

Definitions

  • ABSTRACT A temporary support lug system for hanger tubes is provided by means of which tubular heat exchange members can be tied together and held in place within a steam generator before and while the necessary welding is accomplished.
  • Horizontal tubular heat exchange surface which extends downwardly into the gas passageway of a steam generator must be supported by fluid cooled members, referred to as hanger tubes.
  • hanger tubes are shop attached to the horizontal tubular heat exchange surface.
  • the most economical manner of presently manufacturing these heat exchangers is to fabricate sections in the shop, and assemble them in the field during erection of the steam generator. This presents problems in the field regarding the lifting of the various sections into place, and aligning and holding the sections of vertical hanger tubes while they are welded in place.
  • This invention is directed to a temporary support lug system that can be used for holding tubular heat exchange members in place during erection of a steam generator, and aligning hanger tube ends while they are welded together. Collars are welded to the hanger tube ends, which can be used to support temporary jigs for the purpose of supporting the heat exchange members and aligning the hanger tube ends so that they can be welded together.
  • the temporary jigs are made up of a pair ofdoor hinge lugs.
  • FIG. 1 is a sectional elevation of a rear gas pass of a typical steam generator containing horizontal tubular heat exchange surface which can be easily erected with the aid of the temporary support lug arrangements of this invention;
  • FIG. 2 is an enlarged elevational view of one of the support lug arrangements shown in FIG. 1;
  • FIG. 3 is a sectional plan view of the support lug arrangement taken on line 3-3 of FIG. 2.
  • FIG. 1 of the drawings designates the rear pass of a steam generator, containing a horizontal superheater 12.
  • the superheater I2 is initailly constructed by hoisting panels or sections, designated as 14 and in FIG. 1, into place, and welding these sections together.
  • the superheater 12 is supported from above by distribution header [6 by means of hanger tubes, the upper portions of which are designated 18, 22 and the lower portions 20, 24.
  • the horizontal tubular runs are welded to the hanger tube portions in the shop, prior to being shipped to the field.
  • the panels or sections 14 and 15 are lifted into place one at a time, and are held in place by means of temporary support lug arrangements 26 while the upper and lower portions of the hanger tubes are welded together.
  • Collar members 28 and 30 are welded to the hanger tubes 18 and 20, respectively, near their ends. These collars can be conveniently welded onto the hanger tube sections in the shop.
  • a pair of semi-cylindrical members 32 and 34 are placed on opposite sides of the hanger tube. Each of these members 32, 34 have tabs 36, 38, and 40, 42, respectively, extending from their side edges. These tabs are circular in section, as can be seen in FIG. 3.
  • the circular openings of the two tabs on each side of the tube are in alignment, and bolts 44 and 46 are inserted therethrough, forming a door hinge" type connection on the tube 18.
  • the bolts 44 and 46 extend downwardly through a similar door hinge" arrangement secured to tube 20.
  • Nuts 48 and 50 can be tightened on the bolts 44 and 46, thus acting through the collars 28 and 30 to bring the two ends of tubes 18 and 20 into aligned abutment with each other.
  • a similar support lug arrangement is used to align and bring together the ends of hanger tube sections 22 and 24, which will ultimately support the right hand side of superheater 12 (FIG. 1
  • the hanger tube sections can then be quickly and easily welded in place by a welder, and the support lug arrangements 26 can be removed. Another superheater section can then be lifted into place, and temporarily supported and aligned by support lug arrangements 26 while it is being welded into position.
  • the temporary support lug arrangements 26 can be quickly removed, either by cutting the bolts 44 and 46, or by unthreading the nuts 48 and 50.
  • the entire assembly, with the exception of the collars 28 and 30, can then be removed.
  • These collars since they are of small size, and do not extend significantly in the longitudinal direction along the tube length, can remain in position on the hanger tubes after the steam generator is put into operation. Longitudinal welds on these tubes are undesirable, because of the possibility of tube craking along such welds.
  • An example of the size of the collars that are welded to the tubes would be a 2 k inches outer diameter collar welded to a 2 inches outer diameter tube.
  • the collar height or thickness would be A inch. This size collar can safely be left on the hanger tubes without causing any undue stresses when the stream generator is operated with hot combustion gases passing along the outside of the tubes and superheated steam flowing inside the tubes.
  • the support arrangement of the present invention By using the support arrangement of the present invention, it is not necessary to remove any welded members from tubes, which generally must be done by either cutting or grinding. Such cutting or grinding done on pressure parts, such as hanger tubes, is very time consuming and requires highly skilled labor. Thus it can be seen that the temporary support lug arrangement of the present invention results in the saving of time and money. In a unit which requires thousands of hanger tube welds, there are substantial savings.
  • a temporary support lug arrangement for positioning and holding a pair of upper and lower vertical heat exchange tubes in end-to-end alignment so that they can be welded together, said support lug arrangement including a first collar welded to the upper tube near its lower end, a second collar welded to the lower tube near its upper end, a first pair of mating semicylindrical members which together completely surround the upper tube above the first collar, each of the first semi-cylindrical members having two vertical cylindrical members attached thereto on opposite sides of the upper tube, with the openings of one being in alignment with the openings in the other, a second pair of mating semi-cylindrical members which together completely surround the lower tube beneath the second collar, each of the second semi-cylindrical members having two vertical cylindrical members attached thereto on opposite sides of the lower tube, with the openings of one being in alignment with the openings in the other, and also being in alignment with the openings of the cylindricalmembers attached to the first pair of semi-cylindrical members, first bolt means extending through all

Abstract

A temporary support lug system for hanger tubes is provided by means of which tubular heat exchange members can be tied together and held in place within a steam generator before and while the necessary welding is accomplished.

Description

United States Patent 1 Ambrose et al.
[ TEMPORARY SUPPORT LUG SYSTEM ON HANGER TUBES FOR ERECTION OF PRESSURE PARTS Inventors: Alwin W. Ambrose, Enfield; Hersey B. Nelson, West Granby, both of Conn.
[7 3] Combustion Windsor, Conn.
Filed: June 11, 1971 Appl. No.: 152,320
Assignee: Engineering, Inc.,
US. Cl. ..29/200 P, 228/44, 269/45, 285/2i Int. Cl. ..B23k 37/04 Field of Search ..29/200 1, 200 P; 228/4, 44; 269/37, 43, 45; 285/21, 286, 416
Primary Examiner-Granville Y. Custer, Jr. Assistant Examiner-Neil Abrams Attorney-Robert L. Olson et al.
[ 5 7] ABSTRACT A temporary support lug system for hanger tubes is provided by means of which tubular heat exchange members can be tied together and held in place within a steam generator before and while the necessary welding is accomplished.
1 Claim, 3 Drawing Figures q 42 h 1 I 1 7 n i as Patented May 1, 1973 3,729,797
2 Sheets-Sheet 1 v INVENTORS ALWIN W. AMBROSE HERSEY B. NELSON ATTORNEY Patented May 1, 1973 3,729,797
2 Sheets-Sheet 2:
l i 30 '63", 23-1] I 'I I I I I n 1:. i I! I I 1' I l I 1 1' {I l I 1 1 I: II I] I I I INVENTORS ALWIN W. AMBROSE FIG 2 HERSEY a. NELSON ATTORNEY TEMPORARY SUPPORT LUG SYSTEM ON HANGER TUBES FOR ERECTION OF PRESSURE PARTS BACKGROUND OF THE INVENTION The invention relates to temporary support arrangements used for tieing the tubular heat exchange members in place within a steam generator, and for holding these members in aligned positions while the necessary welding is accomplished. Horizontal tubular heat exchange surface which extends downwardly into the gas passageway of a steam generator must be supported by fluid cooled members, referred to as hanger tubes. These hanger tubes are shop attached to the horizontal tubular heat exchange surface. As steam generators become larger, these heat exchange surfaces likewise grow in size, presenting construction problems. The most economical manner of presently manufacturing these heat exchangers is to fabricate sections in the shop, and assemble them in the field during erection of the steam generator. This presents problems in the field regarding the lifting of the various sections into place, and aligning and holding the sections of vertical hanger tubes while they are welded in place.
SUMMARY OF THE INVENTION This invention is directed to a temporary support lug system that can be used for holding tubular heat exchange members in place during erection of a steam generator, and aligning hanger tube ends while they are welded together. Collars are welded to the hanger tube ends, which can be used to support temporary jigs for the purpose of supporting the heat exchange members and aligning the hanger tube ends so that they can be welded together. The temporary jigs are made up of a pair ofdoor hinge lugs.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional elevation of a rear gas pass of a typical steam generator containing horizontal tubular heat exchange surface which can be easily erected with the aid of the temporary support lug arrangements of this invention;
FIG. 2 is an enlarged elevational view of one of the support lug arrangements shown in FIG. 1; and
FIG. 3 is a sectional plan view of the support lug arrangement taken on line 3-3 of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT Looking now to FIG. 1 of the drawings designates the rear pass of a steam generator, containing a horizontal superheater 12. The superheater I2 is initailly constructed by hoisting panels or sections, designated as 14 and in FIG. 1, into place, and welding these sections together. The superheater 12 is supported from above by distribution header [6 by means of hanger tubes, the upper portions of which are designated 18, 22 and the lower portions 20, 24. The horizontal tubular runs are welded to the hanger tube portions in the shop, prior to being shipped to the field. During initial construction, the panels or sections 14 and 15 are lifted into place one at a time, and are held in place by means of temporary support lug arrangements 26 while the upper and lower portions of the hanger tubes are welded together.
Looking now to FIG. 2, one of the support lug arrangements is shown in more detail. Collar members 28 and 30 are welded to the hanger tubes 18 and 20, respectively, near their ends. These collars can be conveniently welded onto the hanger tube sections in the shop. A pair of semi-cylindrical members 32 and 34 are placed on opposite sides of the hanger tube. Each of these members 32, 34 have tabs 36, 38, and 40, 42, respectively, extending from their side edges. These tabs are circular in section, as can be seen in FIG. 3. The circular openings of the two tabs on each side of the tube are in alignment, and bolts 44 and 46 are inserted therethrough, forming a door hinge" type connection on the tube 18.
The bolts 44 and 46 extend downwardly through a similar door hinge" arrangement secured to tube 20. Nuts 48 and 50 can be tightened on the bolts 44 and 46, thus acting through the collars 28 and 30 to bring the two ends of tubes 18 and 20 into aligned abutment with each other. A similar support lug arrangement is used to align and bring together the ends of hanger tube sections 22 and 24, which will ultimately support the right hand side of superheater 12 (FIG. 1 The hanger tube sections can then be quickly and easily welded in place by a welder, and the support lug arrangements 26 can be removed. Another superheater section can then be lifted into place, and temporarily supported and aligned by support lug arrangements 26 while it is being welded into position.
After the permanent welds have been completed, the temporary support lug arrangements 26 can be quickly removed, either by cutting the bolts 44 and 46, or by unthreading the nuts 48 and 50. The entire assembly, with the exception of the collars 28 and 30, can then be removed. These collars, since they are of small size, and do not extend significantly in the longitudinal direction along the tube length, can remain in position on the hanger tubes after the steam generator is put into operation. Longitudinal welds on these tubes are undesirable, because of the possibility of tube craking along such welds.
An example of the size of the collars that are welded to the tubes would be a 2 k inches outer diameter collar welded to a 2 inches outer diameter tube. The collar height or thickness would be A inch. This size collar can safely be left on the hanger tubes without causing any undue stresses when the stream generator is operated with hot combustion gases passing along the outside of the tubes and superheated steam flowing inside the tubes.
By using the support arrangement of the present invention, it is not necessary to remove any welded members from tubes, which generally must be done by either cutting or grinding. Such cutting or grinding done on pressure parts, such as hanger tubes, is very time consuming and requires highly skilled labor. Thus it can be seen that the temporary support lug arrangement of the present invention results in the saving of time and money. In a unit which requires thousands of hanger tube welds, there are substantial savings.
What is claimed is:
l. A temporary support lug arrangement for positioning and holding a pair of upper and lower vertical heat exchange tubes in end-to-end alignment so that they can be welded together, said support lug arrangement including a first collar welded to the upper tube near its lower end, a second collar welded to the lower tube near its upper end, a first pair of mating semicylindrical members which together completely surround the upper tube above the first collar, each of the first semi-cylindrical members having two vertical cylindrical members attached thereto on opposite sides of the upper tube, with the openings of one being in alignment with the openings in the other, a second pair of mating semi-cylindrical members which together completely surround the lower tube beneath the second collar, each of the second semi-cylindrical members having two vertical cylindrical members attached thereto on opposite sides of the lower tube, with the openings of one being in alignment with the openings in the other, and also being in alignment with the openings of the cylindricalmembers attached to the first pair of semi-cylindrical members, first bolt means extending through all four of the cylindrical members on one side of the upper and lower tubes, second bolt means extending through all four of the cylindrical members on the other side of the upper and lower tubes, first and second nut means associated with the first and second bolt means, the inner diameter of the first and second pair of semi-cylindrical members being smaller than the outer diameter of the first and second collar means, so that tightening of the first and second nut means draws the upper and lower tubes towards each other.

Claims (1)

1. A temporary support lug arrangement for positioning and holding a pair of upper and lower vertical heat exchange tubes in end-to-end alignment so that they can be welded together, said support lug arrangement including a first collar welded to the upper tube near its lower end, a second collar welded to the lower tube near its upper end, a first pair of mating semicylindrical members which together completely surround the upper tube above the first collar, each of the first semi-cylindrical members having two vertical cylindrical members attached thereto on opposite sides of the upper tube, with the openings of one being in alignment with the openings in the other, a second pair of mating semi-cylindrical members which together completely surround the lower tube beneath the second collar, each of the second semi-cylindrical members having two vertical cylindrical members attached thereto on opposite sides of the lower tube, with the openings of one being in alignment with the openings in the other, anD also being in alignment with the openings of the cylindrical members attached to the first pair of semicylindrical members, first bolt means extending through all four of the cylindrical members on one side of the upper and lower tubes, second bolt means extending through all four of the cylindrical members on the other side of the upper and lower tubes, first and second nut means associated with the first and second bolt means, the inner diameter of the first and second pair of semi-cylindrical members being smaller than the outer diameter of the first and second collar means, so that tightening of the first and second nut means draws the upper and lower tubes towards each other.
US00152320A 1971-06-11 1971-06-11 Temporary support lug system on hanger tubes for erection of pressure parts Expired - Lifetime US3729797A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US15232071A 1971-06-11 1971-06-11

Publications (1)

Publication Number Publication Date
US3729797A true US3729797A (en) 1973-05-01

Family

ID=22542424

Family Applications (1)

Application Number Title Priority Date Filing Date
US00152320A Expired - Lifetime US3729797A (en) 1971-06-11 1971-06-11 Temporary support lug system on hanger tubes for erection of pressure parts

Country Status (2)

Country Link
US (1) US3729797A (en)
CA (1) CA963488A (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4492391A (en) * 1982-05-03 1985-01-08 Star Industries, Inc. Thrust rod anchor for pipe joint restraint systems
US4635970A (en) * 1983-10-07 1987-01-13 Haines Robert E Thrust rod anchor for pipe joint restraint systems
US9273525B2 (en) * 2009-06-30 2016-03-01 Antelope Oil Tool & Mfg. Co. Interference-fit stop collar and method of positioning a device on a tubular
US9598913B2 (en) 2009-04-07 2017-03-21 Antelope Oil Tool & Mfg. Co. Friction reducing wear band and method of coupling a wear band to a tubular
US9759023B2 (en) 2007-05-16 2017-09-12 Antelope Oil Tool & Mfg. Co. Apparatus for securing a centralizer to a tubular
US9771763B2 (en) 2007-05-16 2017-09-26 Antelope Oil Tool & Mfg. Co. Low-clearance centralizer
EP4111082A4 (en) * 2020-02-24 2024-03-13 Payten Belt Anti-kinking device

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1775311A (en) * 1928-06-30 1930-09-09 Fred Stovall Welding apparatus
US2267168A (en) * 1941-12-23 Shore pipe
US2344939A (en) * 1942-12-09 1944-03-28 Continental Oil Co Apparatus for welding pipe sections
US3284883A (en) * 1964-06-08 1966-11-15 Haverfield Fern Boyd Line up clamp

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2267168A (en) * 1941-12-23 Shore pipe
US1775311A (en) * 1928-06-30 1930-09-09 Fred Stovall Welding apparatus
US2344939A (en) * 1942-12-09 1944-03-28 Continental Oil Co Apparatus for welding pipe sections
US3284883A (en) * 1964-06-08 1966-11-15 Haverfield Fern Boyd Line up clamp

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4492391A (en) * 1982-05-03 1985-01-08 Star Industries, Inc. Thrust rod anchor for pipe joint restraint systems
US4635970A (en) * 1983-10-07 1987-01-13 Haines Robert E Thrust rod anchor for pipe joint restraint systems
US9759023B2 (en) 2007-05-16 2017-09-12 Antelope Oil Tool & Mfg. Co. Apparatus for securing a centralizer to a tubular
US9771763B2 (en) 2007-05-16 2017-09-26 Antelope Oil Tool & Mfg. Co. Low-clearance centralizer
US9598913B2 (en) 2009-04-07 2017-03-21 Antelope Oil Tool & Mfg. Co. Friction reducing wear band and method of coupling a wear band to a tubular
US10294734B2 (en) 2009-04-07 2019-05-21 Innovex Downhole Solutions, Inc. Friction reducing wear band and method of coupling a wear band to a tubular
US9273525B2 (en) * 2009-06-30 2016-03-01 Antelope Oil Tool & Mfg. Co. Interference-fit stop collar and method of positioning a device on a tubular
EP4111082A4 (en) * 2020-02-24 2024-03-13 Payten Belt Anti-kinking device

Also Published As

Publication number Publication date
CA963488A (en) 1975-02-25

Similar Documents

Publication Publication Date Title
JP2517272B2 (en) Modular exhaust gas steam generator with common boiler casing
US3729797A (en) Temporary support lug system on hanger tubes for erection of pressure parts
GB1348792A (en) Tube-wall repairs
US2916263A (en) Fluid heat exchange apparatus
US3427428A (en) Apparatus and method for welding metal pipes and the like
US3644976A (en) Method for constructing superheater and/or reheater modules
JP2019525108A (en) Heat exchanger and system and method for assembling the heat exchanger
US3644978A (en) Assembly fixture for constructing superheater and/or reheater modules
JP2002213707A (en) Separate type boiler plant and its building method
US1745978A (en) Heat-interchange apparatus
CN208304271U (en) A kind of angle steel flange assembly welding platform
US3016855A (en) Alignment and welding device
US20080128580A1 (en) Polygon Tumble Assembler
US3128736A (en) Raising-supporting-aligning jig for tubular wall construction
CN113399915B (en) Non-power-driven fire replacement tool for field oil transportation special-shaped pipe section and off-site prefabricating method
JP2003222302A (en) Constructing method of exhaust heat recovery boiler and heat transfer tube panel block used in method
CN215200434U (en) Welding platform for oil transportation special-shaped pipe fitting
CN205271242U (en) Vapour cold separation ware dress welds template structure and vapour cold separation ware device
CN104785964A (en) Radiant section coil pipe welding work station
KR200494373Y1 (en) Lifting jig for tube bundle of gas-heater
US2353465A (en) Machine tool drive support
US3411486A (en) Temperature matching header
CN204747792U (en) Coil pipe automatic weld workstation
CN110883492A (en) All-position water wall tube simulated welding frame and simulated welding method
BE553474A (en)