KR100869896B1 - Integrity test method of tube bundle in gas heater - Google Patents

Integrity test method of tube bundle in gas heater Download PDF

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KR100869896B1
KR100869896B1 KR1020070067654A KR20070067654A KR100869896B1 KR 100869896 B1 KR100869896 B1 KR 100869896B1 KR 1020070067654 A KR1020070067654 A KR 1020070067654A KR 20070067654 A KR20070067654 A KR 20070067654A KR 100869896 B1 KR100869896 B1 KR 100869896B1
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test
tube bundle
header
pressure
gas
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김재연
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한국가스공사
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M3/00—Investigating fluid-tightness of structures
    • G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
    • G01M3/26—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/46—Details, e.g. noise reduction means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/02—Header boxes; End plates
    • F28F9/04—Arrangements for sealing elements into header boxes or end plates
    • F28F9/16—Arrangements for sealing elements into header boxes or end plates by permanent joints, e.g. by rolling
    • F28F9/18—Arrangements for sealing elements into header boxes or end plates by permanent joints, e.g. by rolling by welding
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M3/00—Investigating fluid-tightness of structures
    • G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
    • G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
    • G01M3/06—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point by observing bubbles in a liquid pool
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/91—Investigating the presence of flaws or contamination using penetration of dyes, e.g. fluorescent ink
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02—Details not specific for a particular testing method
    • G01N2203/022—Environment of the test
    • G01N2203/023—Pressure

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Thermal Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Examining Or Testing Airtightness (AREA)

Abstract

An integrity check method for a tube bundle in a gas heater can cut down on replacement cost of the tube bundle by completely repairing the defect site through welding repair in order to reuse the tube bundle. An integrity check method for a tube bundle in a gas heater includes a visual inspection step(S1) seeking out the defect site with the naked eyes; an airtight and withstand voltage test step(S2) for mounting a header on the tube bundle and observing the pressure change with pressurizing and maintaining injected airtight test gas in order to determine whether defects exist; a first immersing test step(S3) for immersing the tube bundle and the header assembly filled with the airtight test gas in a water tub and observing the bubble generation in order to determine whether defects exist; a PT test step(S4) performing PT inspection by infiltrating the penetrating liquid into the tube sheet of the tube bundle; a welding repair step(S5) for welding the defect site discovered in the PT test step; and a second immersing test step(S6) for immersing the tube bundle and header assembly again in the water tub and observing the bubble generation in order to confirm the repair.

Description

가스히터 튜브번들 건전성 검사방법{integrity test method of tube bundle in gas heater}Integrity test method of tube bundle in gas heater

본 발명은 가스히터 튜브번들 건전성 검사방법에 관한 것으로, 특히 튜브시트부의 용접 결함부위를 찾아내기 위한 가스히터 튜브번들 건전성 검사방법에 관한 것이다.The present invention relates to a gas heater tube bundle integrity test method, and more particularly to a gas heater tube bundle integrity test method for finding a weld defect of the tube sheet portion.

천연가스는 해외 원산지에서 채취되어 액체상태(LNG)로 국내에 도입되며, 이를 다시 기화하여 발전소 등에 직접 공급하거나 도시가스회사를 통해 일반 가정 및 사무실 등에 공급하고 있다.Natural gas is collected from overseas origin and introduced into the liquid state (LNG) in Korea, and it is vaporized and supplied directly to power plants, etc., or to general homes and offices through city gas companies.

한편, 천연가스를 수요처로 공급하기 위해 생산기지에서 공급관리소로 공급되는 천연가스는 고압(10~70㎏/㎠)이므로 수요처로 연결된 배관을 통해 공급하기 전에 압력조절밸브(PCV ; Pressure control valve)를 통해 적절한 압력으로 감압하여 공급하게 되는데, 감압과정에서 천연가스의 온도가 1㎏/㎠ 감압 시 마다 약 0.56℃ 온도강하가 발생하므로 압력조절밸브 등 배관라인의 기능이 저하될 가능성이 내재되어 안전 및 안정 운영이 원활하게 이루어지지 않을 수 있다.On the other hand, the natural gas supplied from the production base to the supply control station to supply natural gas to the demand source is a high pressure (10 ~ 70㎏ / ㎠), so before supplying through the piping connected to the demand source (PCV; Pressure control valve) It is supplied by reducing the pressure to an appropriate pressure.In the process of decompression, a temperature drop of about 0.56 ℃ occurs whenever the temperature of natural gas is reduced by 1㎏ / ㎠. And stable operation may not be performed smoothly.

따라서, 상기 압력조절밸브로 천연가스를 공급하기 전에 감압과정에서 냉각 으로 인한 결빙이 발생하지 않을 정도의 온도로 미리 예열해 주게 되는데, 천연가스의 예열은 가스히터 본체에서 가스를 연료로 버너를 이용하여 물을 가열하고 가열된 온수 속으로 가스히터 튜브번들을 침조시켜 가스히터 튜브번들 내부로 흐르는 가스를 승온시키는 간접가열 방식을 사용한다.Therefore, before supplying the natural gas to the pressure control valve, it is preheated to a temperature such that freezing due to cooling does not occur in the depressurization process. The preheating of the natural gas is performed using a burner as a fuel in the gas heater body. Indirect heating is used to heat the water and increase the gas flowing into the gas heater tube bundle by immersing the gas heater tube bundle into the heated hot water.

상기 튜브번들(tube bundle)은 도 1,2에 도시된 바와 같이, 다수의 U자형 튜브(1)들이 다발을 이루어 튜브시트(2)에 용접된 것으로 다수의 튜브(1)를 이용함으로써 튜브번들을 통과하는 유체와 외부와의 열교환 면적을 증가시켜 보다 효율적인 열교환 작용이 이루어지도록 구성된 것이다.The tube bundle is a bundle of a plurality of U-shaped tubes (1) welded to the tube sheet (2) as shown in Figures 1 and 2 by using a plurality of tubes (1) By increasing the heat exchange area between the fluid passing through and the outside is configured to achieve a more efficient heat exchange action.

따라서, 튜브시트(2)의 정면에는 상기 튜브(1)들의 양쪽 단부가 튜브시트의 원판면을 반분한 구역에 각각 밀집 배치되어 입구와 출구로서 작용하도록 되어 있다. 또한 튜브시트(2)의 외측 플랜지 부분에는 일정 간격으로 볼트체결공(2a)이 형성되어 튜브시트(2)와 온수순환라인을 연결해 주는 헤더(header;도 5참조)가 결합될 수 있도록 되어 있다.Therefore, the front end of the tube sheet 2 is arranged so that both ends of the tubes 1 are densely arranged in the half-divided area of the disc surface of the tube sheet so as to function as an inlet and an outlet. In addition, a bolt fastening hole 2a is formed at a predetermined interval on the outer flange portion of the tube sheet 2 so that a header connecting the tube sheet 2 and the hot water circulation line can be coupled. .

한편, 상기와 같은 구조의 튜브번들은 단순한 밴딩 파이프인 튜브(1) 자체에는 거의 결함이 발생하지 않고, 주로 튜브(1)와 튜브시트(2)의 사이에 용접불량이나 제작 및 운반시의 충격에 의해 크랙이 발생하여 이를 통해 가스의 누설이 발생하게 된다.On the other hand, the tube bundle of the structure as described above almost no defects in the tube (1) itself, which is a simple bending pipe, mainly weld failure between the tube (1) and the tube sheet (2) or impact during production and transportation Cracks are generated by the gas leakage through this.

따라서, 튜브번들의 건전성 검사를 통해 누설이 발생하는 지점을 찾아 보강용접하여 보수하게 된다.Therefore, through the integrity test of the tube bundle to find the point where the leakage occurs to be repaired by reinforcement welding.

종래의 튜브번들 건전성 검사는 도 3에 도시된 바와 같이, 육안검사, 침투탐 상검사(이하, PT검사라 칭한다; 모세관 현상을 이용한 표면 결함 검사법으로서, 표면세척→침투액 도포→표면세척→현상액 도포→현상의 단계로 이루어진다. 검사대상물의 표면에 결함이 있을 경우 침투액이 그 결함부위로 침투하게 되고, 침투된 침투액이 현상액에 의해 흡출되어 현상액 도포 표면에 다른 색깔로 표출됨으로써 결함부위의 검출이 용이하다.)를 통해 누수부위를 찾아내고 용접보수 한 뒤, 다시 보수부위만을 PT검사하여 보수여부를 확인하고, 최종적으로 튜브번들에 헤더를 부착하고 질소를 소정압으로 주입/유지하여 질소압력의 변화를 통해 튜브번들의 기밀 상태를 최종 점검하고 있다.Conventional tube bundle integrity test is a visual inspection, penetration test (hereinafter referred to as PT test; surface defect inspection method using capillary phenomenon, as shown in Figure 3, surface cleaning → application of osmotic fluid → surface cleaning → developer application) → If there is a defect on the surface of the object to be inspected, the penetration solution penetrates into the defect site, and the penetrated solution is sucked out by the developer and expressed in a different color on the developer coating surface, making it easier to detect the defect site. After finding leaking part and repairing welding, repairing PT again by checking only repaired part and finally checking the repaired part. Finally, attaching header to tube bundle and injecting / maintaining nitrogen at predetermined pressure to change nitrogen pressure. We are finally checking the tightness of the tube bundle.

상기와 같이 질소를 사용한 기밀 및 내압시험에서 압력저하가 발생하면 여전히 결함부위가 존재하는 것으로 판단하고, 상기 과정을 반복 실시하였다.As described above, when the pressure drop occurred in the airtight and the pressure resistance test using nitrogen, it was determined that the defect site still existed, and the above process was repeated.

그런데 종래의 경우, 극히 미세한 크랙(헤어크랙;hear crack)의 경우에는 PT검사나 기밀 및 내압시험에 의해 용이하게 검출되지 않으므로 시험과정을 여러 번 반복해야 하는 등 튜브번들 건전성 검사의 신뢰성이 떨어지고, 또한 결국 결함부위를 찾아내지 못한 경우에는 재보수가 불가하여 튜브번들 전체를 교환해야 하므로 비용이 소모가 크게 발생하는 문제점이 있었다.However, in the conventional case, extremely fine cracks (hear cracks) are not easily detected by PT test or airtightness and pressure test, so the reliability of the tube bundle integrity test is inferior, such as the need to repeat the test process several times. In addition, in the event that it is not possible to find a defective part, there is a problem in that the cost is largely consumed because the entire tube bundle needs to be replaced because it is impossible to repair.

이에 본 발명은 상기와 같은 문제점을 해결하기 위해 안출된 것으로, 검사과정을 반복수행하지 않고도 튜브와 튜브시트 사이의 미세한 결함을 확실하게 찾아내어 보수함으로써 튜브번들의 건전성 확보가 용이하고 그에 소요되는 비용을 절감할 수 있도록 된 가스히터 튜브번들 건전성 검사방법을 제공함에 그 목적이 있다.Accordingly, the present invention has been made to solve the above problems, it is easy to secure the integrity of the tube bundle and cost by reliably find and repair the microscopic defects between the tube and the tube sheet without repeating the inspection process The purpose of the present invention is to provide a gas heater tube bundle integrity test method that can reduce the cost.

상기와 같은 목적을 달성하기 위한 본 발명은, The present invention for achieving the above object,

육안으로 결함부위를 찾아내는 육안검사단계와;A visual inspection step of finding defects with the naked eye;

상기 육안검사단계 이후, 튜브번들에 헤더를 장착하고, 기밀시험기체를 주입하고 가압/유지하면서 압력변화를 관찰하여 결함여부를 찾아내는 기밀 및 내압시험단계와;After the visual inspection step, the airtight and pressure test step of mounting the header in the tube bundle, injecting the airtight test gas and observing the pressure change while pressing / maintaining the airtight test;

상기 기밀 및 내압시험단계에서 기밀시험기체가 충진된 튜브번들과 헤더 조립체를 수조에 침수시켜 기포발생여부를 관찰하여 결함여부를 찾아내는 1차침수시험단계;A first immersion test step of immersing a tube bundle and a header assembly filled with an airtight test gas in a water tank in the airtightness and pressure test step and observing the occurrence of bubbles by finding a defect;

상기 1차침수시험단계 이후, 상기 튜브번들의 튜브시트에 침투액을 가압 침투시켜 PT검사를 실시하는 가압PT검사단계와;After the first immersion test step, the PT test step of performing a PT test by penetrating the penetration solution into the tube sheet of the tube bundle;

상기 가압PT검사단계에서 발견된 결함부위를 용접하여 보수하는 용접보수단계;A welding repair step of repairing and repairing a defective part found in the pressure PT inspection step;

상기 용접보수단계 이후, 튜브번들과 헤더 조립체를 다시 수조에 침수시켜 기포발생여부를 관찰하여 보수여부를 확인하는 2차침수시험단계;After the welding repair step, the second immersion test step of immersing the tube bundle and the header assembly in the water tank again to observe whether or not bubbles are generated;

를 포함하여 구성된다.It is configured to include.

따라서, 본 발명에 의하면 PT검사단계에 앞서 기밀 및 내압시험을 진행하므로 크랙의 성장에 의해 미세 크랙 검출이 용이해진다.Therefore, according to the present invention, since the airtightness and withstand pressure tests are performed before the PT inspection step, the cracks are easily detected by the growth of the cracks.

또한, 침수시험단계를 포함하므로 누수가 발생하는 미세 결함부위의 존재 여부를 확실하게 알 수 있다.In addition, it includes a submerged test step, it is possible to know whether the presence of the micro-defect site that leaks.

또한, 본 발명의 PT검사는 단순 PT검사가 아니라, 헤더 장착상태에서 침투액을 주입/가압 및 유지하는 단계를 가지는 가압PT검사로서 크랙으로의 침투액 침투가 원활하게 이루어지므로 미세 크랙 검출이 용이하다.In addition, the PT test of the present invention is not a simple PT test, but is a pressurized PT test having a step of injecting / pressurizing and maintaining the penetrant in the header mounted state, so that the penetrant penetrates into the crack smoothly, so that the minute crack is easily detected.

또한, 본 발명은 기밀 및 내압시험단계의 직전과 가압PT검사의 현상액 도포 직전에 튜브시트를 가열하는 단계를 포함함으로써 열팽창에 의해 크랙이 확장되어 침투액 침투 및 침투액과 현상액의 접촉이 원활히 이루어짐으로써 미세 크랙 검출이 용이하다.In addition, the present invention includes the step of heating the tube sheet immediately before the airtight and pressure-resistant test step and just before the application of the developer of the pressure PT test, so that the cracks are expanded by thermal expansion, so that the penetration of the penetrating solution and the contact between the penetrating solution and the developer are fine. Crack detection is easy.

이상과 같이 본 발명은 미세한 결함부위도 확실하게 검출해 낼 수 있게 되어 용접보수를 통해 완벽하게 보수하여 재사용할 수 있게 됨으로써 결함부위 검출불능에 의해 튜브번들 전체를 교환하던 낭비 문제를 해소할 수 있게 되는 효과가 있다.As described above, the present invention is able to reliably detect minute defects, so that it can be completely repaired and reused through welding repair, thereby eliminating the wasted problem of exchanging the entire tube bundle due to inability to detect defects. It is effective.

이하, 본 발명을 첨부된 예시도면을 참조하여 상세히 설명한다.Hereinafter, with reference to the accompanying drawings, the present invention will be described in detail.

도 4는 본 발명에 따른 튜브번들 건전성 검사방법을 나타낸 블럭도이다.Figure 4 is a block diagram showing a tube bundle integrity test method according to the present invention.

본 발명은 육안검사단계(S1), 기밀 및 내압시험단계(S2), 1차침수시험단계(S3), 가압PT검사단계(S4), 용접보수단계(S5), 2차침수시험단계(S6)로 이루어진다.The present invention is visual inspection step (S1), airtightness and pressure resistance test step (S2), the first immersion test step (S3), pressure PT inspection step (S4), welding repair step (S5), secondary immersion test step (S6) )

상기 육안검사단계(S1)에서는 튜브시트(2)면에서 육안으로 식별 가능한 비교적 큰 결함을 찾아내게 된다.In the visual inspection step S1, a relatively large defect that can be visually identified from the tube sheet 2 surface is found.

이어, 상기 기밀 및 내압시험단계(S2)에서 튜브시트(2)에 헤더를 장착하고, 질소 등의 기밀시험기체를 소정압으로 주입/유지(설계압력의 1.1배, 유지시간 30분)하면서 압력 게이지를 관찰하여 압력변화 여부를 통해 결함 유무를 검사한다.Subsequently, the header is mounted on the tube sheet 2 in the airtightness and pressure resistance test step (S2), and the pressure while injecting / maintaining a gastight test gas such as nitrogen at a predetermined pressure (1.1 times the design pressure and a holding time of 30 minutes) is applied. Observe the gauge to check for defects through pressure changes.

이어 상기와 같이 헤더가 장착되어 있는 튜브번들(튜브번들과 헤더 조립체)을 수조에 담그어 기포 발생 여부를 관찰하는 1차침수시험단계(S3)를 진행한다.Subsequently, the first immersion test step (S3) of immersing the tube bundle (tube bundle and header assembly) in which the header is mounted in a water tank and observing the occurrence of bubbles is performed.

상기 세 단계를 거치면서 용접부위의 결함 위치는 정확히 알 수 없을지라도 결함의 존재 유무는 확실히 알 수 있게 된다. 즉, 기포가 발생하면 용접결함이 존재하는 것이다.Through the above three steps, even if the location of the defect in the welded portion cannot be known accurately, the presence of the defect can be known with certainty. That is, when bubbles are generated, weld defects exist.

이어, 가압PT검사단계(S4)를 실시한다. 상기 가압PT검사단계(S4)는 다음과 같이 진행된다.Then, the pressure PT inspection step (S4) is carried out. The pressure PT inspection step (S4) proceeds as follows.

이전의 기밀 및 내압시험단계(S2)에서 주입된 기밀시험기체가 여전히 헤더가 장착된 튜브번들의 내부에 있는 상태이므로, 먼저 주입되어 있는 기밀시험기체를 완전히 배출한다.Since the hermetic test gas injected in the previous hermetic and withstand pressure test step (S2) is still in the inside of the tube bundle with the header, the hermetic test gas first discharged completely.

도 5에 도시되어 있는 바와 같이, 헤더(3)의 상/하부에는 복수의 주입구(3a; 유체 충진과 가압을 위한 연통구로서 개폐밸브 구비)와 배출구(3b; 충진 유체의 드 레인을 위한 연통구로서 개폐밸브 구비)들이 형성되어 있어서, 필요한 유체를 주입하고 가압하며 배출할 수 있도록 되어 있다.As shown in FIG. 5, the upper and lower portions of the header 3 have a plurality of inlets 3a (with on / off valves as communication ports for filling and pressurizing) and outlets 3b for communicating with the drain of the filling fluid. The opening and closing valve is provided as a sphere, so that the required fluid can be injected, pressurized and discharged.

상기와 같이 기밀시험기체를 완전 배출한 후에는 헤더(3)의 내부로 침투액을 주입하고(헤더 및 튜브번들 내용적의 100%), 가압펌프를 이용하여 소정압으로 가압하고 가압상태를 소정시간동안 유지한다.(50bar까지 1차 승압 후, 10분 유지, 이어 80bar까지 2차 승압한 뒤, 30분 유지)After completely discharging the airtight test gas as described above, the infiltration liquid is injected into the inside of the header 3 (100% of the header and tube bundle contents), pressurized to a predetermined pressure using a pressure pump, and the pressurized state is maintained for a predetermined time. (1st boost up to 50bar, 10 min, then 2 boost up to 80bar, 30min)

상기 가압상태 유지시간이 경과한 후에는 압력을 대기압까지 감압한 후 침투액을 완전히 배출하고, 튜브번들로부터 헤더를 분리한다.After the pressure maintaining time has elapsed, the pressure is reduced to atmospheric pressure, and then the permeate is completely discharged, and the header is separated from the tube bundle.

이어, 튜브번들의 튜브시트(2)면 전체에 PT검사를 실시한다.Subsequently, a PT test is performed on the entire tube sheet 2 surface of the tube bundle.

이때 헤더로 침투액을 주입한 것에 의하여 튜브시트(2)의 표면에는 이미 침투액이 도포되어 있는 상태이므로 우선 표면을 세척하고 현상액을 도포한다.At this time, since the penetration solution is already applied to the surface of the tube sheet 2 by injecting the penetration solution into the header, the surface is first washed and the developer is applied.

현상액 도포에 의해 결함부위에 침투되어 있던 침투액이 흡출되어 식별하기 용이하게 표시된다.(현상과정)The developer penetrates the defect by the application of the developer and is easily displayed for identification.

현상이 종료된 후에는 발견된 결함 부위를 용접보수(S5)한다.After the development is finished, the repaired defect site is repaired (S5).

용접보수(S5) 후에는 튜브시트(2) 표면의 현상액을 세척하여 제거하고, 헤더(3)를 재장착하고 수조에 담그어 2차침수시험단계(S6)를 실시하여 결함의 존재 여부를 최종 확인한다.After welding repair (S5), the developer on the surface of the tube sheet (2) is washed and removed, and the header (3) is remounted and immersed in a water bath to perform the second immersion test step (S6) to confirm the presence of a defect. do.

본 발명은 상기와 같이 PT검사를 실시하기 이전에 기밀 및 내압시험(S2)를 선 실시하므로 미세 크랙의 성장을 통해 침투액이 크랙 속으로 침투되기 용이한 조건을 만들어 줌으로써 미세 크랙도 보다 용이하게 발견할 수 있게 된다.Since the present invention performs the airtightness and pressure resistance test (S2) before the PT test as described above, the microcracks are more easily found by making a condition that is easy to penetrate into the cracks through the growth of the microcracks. You can do it.

또한, 본 발명은 대기압에 노출된 상태에서 침투액을 도포하는 것이 아니라, 헤더 속으로 침투액을 충진하고 소정 압력으로 가압한 후 유지시간을 가지므로 침투액이 크랙 속으로 보다 원활하게 침투될 수 있게 되어 전술한 바와 마찬가지로 미세 크랙을 보다 확실하게 검출할 수 있게 된다.In addition, the present invention is not to apply the permeate in the state exposed to atmospheric pressure, but the filling time into the header and pressurized to a predetermined pressure has a holding time, so that the permeate can penetrate into the crack more smoothly As described above, fine cracks can be detected more reliably.

또한, 본 발명은 상기와 같은 침투액 침투가 보다 원활하게 이루어지도록 하기 위하여 상기 기밀 및 내압시험단계(S2)의 이전에 튜브시트(2)를 가열 및 냉각하는 단계를 포함한다.In addition, the present invention includes the step of heating and cooling the tube sheet (2) before the airtight and pressure-resistant test step (S2) in order to make the penetration of the penetration liquid more smoothly.

즉, 가열토치로 튜브시트(2)의 표면을 가열하여 소재의 열팽창에 의해 튜브시트 표면의 크랙을 확장하는 것이다. 이와 같이 가열되어 크랙이 확장된 후, 이후 단계의 진행이 가능할 정도로 소정 시간동안 적절히 냉각시킨 후 검사를 진행한다.That is, the surface of the tube sheet 2 is heated with a heating torch to expand cracks on the surface of the tube sheet by thermal expansion of the material. After heating and cracks are expanded in this way, the test is performed after appropriately cooling for a predetermined time so that the subsequent steps can be performed.

상기와 같이 가열을 통해 크랙의 확장이 이루어지면 이후의 기밀 및 내압시험단계(S2), 1차침수시험단계(S3) 및 가압PT검사단계(S4) 모두에서 결함의 검출이 보다 용이하게 이루어짐은 물론이다.When the crack is expanded through heating as described above, defects can be more easily detected in both the airtightness and pressure resistance test step (S2), the first immersion test step (S3), and the pressurized PT test step (S4). Of course.

한편, 상기 가열 및 냉각단계를 가압PT검사(S4)의 마지막 과정인 PT검사단계에서 현상액을 도포하기 전에 다시 한 번 실시할 수 있다.On the other hand, the heating and cooling step may be carried out once again before applying the developer in the PT test step of the final process of the pressure PT test (S4).

이는 1차 가열 및 냉각단계 이후 검사 진행과 함께 시간이 많이 경과하여 크랙이 재수축한 것을 다시 팽창시켜 크랙의 입구를 넓혀 침투된 도포액과 표면에 도포되는 현상액과의 접촉면적을 증가시킴으로써 현상 작용이 보다 원활히 이루어지도록 하여 결함부위 식별을 용이하게 하기 위해서이다.It develops by increasing the contact area between the penetrating coating solution and the developer applied to the surface by expanding the crack's inlet by re-expanding the crack's re-shrinkment after a long time as the inspection progresses after the first heating and cooling step. The reason for this is to facilitate the identification of defects by making it more smooth.

도 1은 튜브번들의 사시도,1 is a perspective view of the tube bundle,

도 2는 튜브번들의 튜브시트 정면도,2 is a front view of the tube sheet of the tube bundle;

도 3은 종래 튜브번들 건전성 검사방법을 나타낸 블럭도,Figure 3 is a block diagram showing a conventional tube bundle integrity test method,

도 4는 본 발명에 따른 튜브번들 건전성 검사방법을 나타낸 블럭도,Figure 4 is a block diagram showing a tube bundle integrity test method according to the present invention,

도 5는 튜브번들의 헤더 장착 상태도이다.5 is a diagram illustrating a header mounting state of the tube bundle.

*도면의 주요 부분에 대한 부호의 설명** Description of the symbols for the main parts of the drawings *

1 : 튜브 2 : 튜브시트1 tube 2 tube sheet

2a : 볼트체결공 3 : 헤더2a: bolt fastener 3: header

3a : 주입구 3b : 배출구3a: inlet 3b: outlet

Claims (5)

육안으로 결함부위를 찾아내는 육안검사단계(S1)와;A visual inspection step (S1) for finding defects with the naked eye; 상기 육안검사단계(S1) 이후, 튜브번들에 헤더를 장착하고, 기밀시험기체를 주입하고 가압/유지하면서 압력변화를 관찰하여 결함여부를 찾아내는 기밀 및 내압시험단계(S2)와;After the visual inspection step (S1), the header is mounted on the tube bundle, the airtightness and pressure test step (S2) to find the defect by observing the pressure change while injecting and pressing / maintaining the gas tight test gas (S2); 상기 기밀 및 내압시험단계(S2)에서 기밀시험기체가 충진된 튜브번들과 헤더 립체를 수조에 침수시켜 기포발생여부를 관찰하여 결함여부를 찾아내는 1차침수시험단계(S3);The first immersion test step (S3) of immersing the tube bundle and the header assembly filled with the airtight test gas in a water tank in the airtightness and pressure resistance test step (S2) and observing whether or not bubbles are generated; 상기 1차침수시험단계(S3) 이후, 상기 튜브번들의 튜브시트에 침투액을 가압 침투시켜 PT검사를 실시하는 가압PT검사단계(S4)와;After the first immersion test step (S3), and a pressure PT test step (S4) for performing a PT test by penetrating the penetration solution into the tube sheet of the tube bundle; 상기 가압PT검사단계(S4)에서 발견된 결함부위를 용접하여 보수하는 용접보수단계(S5);Welding repair step (S5) for repairing by repairing the defects found in the pressure PT inspection step (S4); 상기 용접보수단계(S5) 이후, 튜브번들과 헤더 조립체를 다시 수조에 침수시켜 기포발생여부를 관찰하여 보수여부를 확인하는 2차침수시험단계(S6);After the welding repair step (S5), the second bundle immersion test step (S6) to immerse the tube bundle and the header assembly in the water tank again to check whether the bubble is generated or not; 를 포함하여 구성된 가스히터 튜브번들 건전성 검사방법.Gas heater tube bundle integrity test method comprising a. 청구항 1에 있어서, 상기 가압PT검사단계(S4)는 헤더에서 기밀시험기체를 배출하는 단계와, 헤더로 침투액을 주입하는 단계와, 가압 및 유지하는 단계와, 헤더로부터 침투액을 배출하는 단계와, 튜브번들로부터 헤더를 분리하는 단계와, 헤더 가 분리된 튜브번들의 튜브시트에 PT검사를 실시하는 PT검사단계로 이루어진 것을 특징으로 하는 가스히터 튜브번들 건전성 검사방법.The method of claim 1, wherein the pressure PT inspection step (S4) comprises the steps of: discharging the gas-tight test gas from the header, injecting the permeate into the header, pressurizing and maintaining, and discharging the permeate from the header; Separating the header from the tube bundle, and PT inspection step of performing a PT test on the tube sheet of the tube bundle separated from the header gas heater tube bundle integrity test method. 청구항 2에 있어서, 상기 PT검사단계는 튜브시트 표면의 침투액을 제거하는 표면세척단계와, 세척된 표면에 현상액을 도포하는 현상액 도포단계와, 크랙에 침투된 침투액이 상기 도포된 현상액 외부로 흡출되는 현상단계로 이루어진 것을 특징으로 하는 가스히터 튜브번들 건전성 검사방법.The method of claim 2, wherein the PT inspection step includes a surface washing step of removing the penetrating solution from the surface of the tube sheet, a developer applying step of applying the developer to the cleaned surface, and a penetrating solution penetrating into the crack is sucked out of the coated developer. Gas heater tube bundle integrity test method characterized in that the development step. 청구항 1에 있어서, 상기 기밀 및 내압시험단계(S2) 실시 전에 튜브시트 표면을 토치로 가열하여 미세 크랙을 확장시키고, 시험진행이 가능하도록 적정 온도로 냉각시키는 가열 및 냉각단계를 실시하는 것을 특징으로 하는 가스히터 튜브번들 건전성 검사방법.The method of claim 1, wherein before the airtightness and pressure test step (S2), the surface of the tube sheet is heated with a torch to expand fine cracks, and a heating and cooling step of cooling to an appropriate temperature to perform a test can be performed. Gas heater tube bundle integrity test method. 청구항 3에 있어서, 상기 현상액 도포단계 실시 전에 튜브시트 표면을 토치로 가열하여 미세 크랙을 확장시키고, 시험진행이 가능하도록 적정 온도로 냉각시키는 가열 및 냉각단계를 실시하는 것을 특징으로 하는 가스히터 튜브번들 건전성 검사방법.4. The gas heater tube bundle integrity of claim 3, wherein the surface of the tube sheet is heated with a torch before the application of the developer solution to expand the microcracks, and a heating and cooling step of cooling the tube sheet to an appropriate temperature to perform a test proceeds. method of inspection.
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KR20200001697A (en) * 2018-06-28 2020-01-07 현대비씨엔지니어링(주) Apparatus and method for testing leakage of heat exchanger with tube bundle
CN114112220A (en) * 2021-12-15 2022-03-01 中航贵州飞机有限责任公司 Containing type air tightness test device and test method
KR102564265B1 (en) * 2023-05-24 2023-08-04 주식회사 올네이션 Liquid penetrant testing method for small cracks

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KR20000012705A (en) * 1999-12-20 2000-03-06 장상익 The bronze welding method of a segment tube
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KR200465212Y1 (en) * 2010-08-18 2013-02-07 주식회사 한국가스기술공사 Tester is secret existence of bundle tube
CN108151972A (en) * 2017-12-11 2018-06-12 中国海洋石油集团有限公司 Large container end cap flange leakage detection method and its detection instrument
KR20200001697A (en) * 2018-06-28 2020-01-07 현대비씨엔지니어링(주) Apparatus and method for testing leakage of heat exchanger with tube bundle
KR102077700B1 (en) * 2018-06-28 2020-02-17 현대비씨엔지니어링(주) Apparatus for testing leakage of heat exchanger with tube bundle
CN114112220A (en) * 2021-12-15 2022-03-01 中航贵州飞机有限责任公司 Containing type air tightness test device and test method
CN114112220B (en) * 2021-12-15 2023-09-05 中航贵州飞机有限责任公司 Containing type air tightness test device and test method
KR102564265B1 (en) * 2023-05-24 2023-08-04 주식회사 올네이션 Liquid penetrant testing method for small cracks
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