KR200191426Y1 - Equipment for leak test with tracer gas - Google Patents

Abstract

The present invention is designed for ammonia, helium or petroleum gas in LNG carriers, Mock-UPs of LNG carriers, insulated spaces in LNG storage tanks of LNG carriers and LNG carriers, medium and small airtight vessels and pipelines. The present invention relates to a leak inspection apparatus using a tracer gas that inspects the confidentiality by using a tracer gas such as a halogen gas.

The present invention is connected to a gas injection line, a gas exhaust line and a safety valve line to a predetermined portion of the airtight container to be inspected, an adjusting unit for injecting or discharging a mixed gas, a dry air (or nitrogen gas) digital flow meter, and a tracking gas It consists of a digital flow meter, a pressure reducing and mixing tank, a vacuum pump, and a neutralization tank, and it is convenient to discharge and inject gas even in medium and small-capacity airtight containers that were difficult to inspect in the past. There is an advantage that the leak test using tracer gas for the airtight container, which was not easily done due to difficulty, is easily performed.

Description

Leak Inspection System Using Tracer Gas {EQUIPMENT FOR LEAK TEST WITH TRACER GAS}

The present invention relates to a device for detecting a leak of a predetermined hermetic container. More specifically, the present invention relates to an LNG carrier, a mock-up of an LNG carrier, an LNG storage tank of an LNG carrier and an LNG carrier. The present invention relates to a leak inspection apparatus using a tracer gas that inspects a gas tightness using a tracer gas such as ammonia, helium or halogen gas in an adiabatic space, a medium / small airtight container, and a pipeline.

In general, LNG storage tanks of LNG carriers and LNG take-up bases are made of stainless steel or invar steel called MEMBRANE to transport or store liquefied natural gas at cryogenic temperatures (-162 ℃). Is composed of double insulation space.

Therefore, the LNG storage tank is subjected to the airtight test of the heat insulating space of the storage tank surrounding the outside when the membrane is manufactured to completely maintain the airtight. This gas tightness test is a leak gas detection test using a conventional tracer gas. As the tracer gas, ammonia, helium or halogen gas as described above is used.

First, the leakage test performed by using the ammonia tracer gas, injecting the ammonia tracer gas into the adiabatic space of the storage tank, applying the reaction reagent to the outer surface, and reacting with the ammonia gas leaking through the leaked place. The leak test is performed by detecting the discoloration of the reagent. The leak test using helium or halogen gas is injected into the insulation space and helium leaks through leaks that may be present in the weld zone on the outer surface of the membrane. This is a test method that detects the location and amount of leakage of a halogen tracer gas using a helium or halogen tracer gas detector.

In addition, in order to inspect the leakage of the airtight space by injecting the tracer gas, prior to injecting the tracer gas into the airtight container, the moisture in the airtight space, that is, the insulation space of the LNG storage tank, is removed or other gas is discharged. To be done.

In addition, the process of removing moisture and discharging the gas is realized by repeating the process of injecting or discharging pure dry air (or nitrogen gas: the same below) into the airtight space several times.

Accordingly, in order to inspect the gas leakage in the hermetic space, an inspection apparatus for injecting or discharging the mixed gas of the dry air (or nitrogen gas) and the tracer gas into the hermetic space is inevitably required.

Currently, in Korea, inspection equipment for leak testing of storage tanks of LNG carriers or LNG receiving stations has been introduced and used in foreign countries such as France and Japan.

Such an inspection apparatus will be described with reference to the accompanying drawings.

1 is a schematic configuration diagram of a leak test apparatus for detecting a leak of an insulation space in a LNG storage tank of a conventional LNG carrier.

As shown, 10 is an LNG storage tank loaded on an LNG carrier, not shown, and schematically shows a front end thereof, and is configured in a polygonal shape. The outside of the LNG storage tank 10 is configured to surround the first insulation portion 11 and the second insulation portion 12 which is a heat insulating space.

In addition, the tracer gas 21 is introduced into the adjusting unit 20 through the line 32, and the drying air (or nitrogen gas) 22 to the adjusting unit 20 through the drying apparatus 23 and the line 33. It is pulled in. The adjusting unit 20 injects mixed gas (dry air + tracking gas) into the first and second heat insulating parts 11 and 12 through the bottom of the mixed gas injection line 27 and the LNG storage tank 10. The gas injection line 27 installed in the LNG storage tank 10 is connected to a plurality of inlets 14 through a gas distributor 13 so that the mixed gas is connected to the first and second insulation units 11. Disperse evenly into 12).

In addition, the gas injection / discharge line 28 connected from the adjusting unit 20 is connected to the first heat insulating part 11 and the second heat insulating part 12 through the pressure measuring device 15 and the pressure measuring device 18, respectively. Equipped with pure dry air (or nitrogen gas), or when discharging the gas filled in the first and second heat insulating parts (11) (12). In addition, the first heat insulating part 11 is configured such that the safety valve line 41 is connected to the safety valve tank 40 through the concentration meter 43, and the gas discharge line 29 connected from the adjusting part 20. It is configured to be connected to the ammonia dilution tank 30.

Reference numerals 16, 17, 19, 24, 25, 31 and 42 are valves and 26 are pipe connections.

On the other hand, the accompanying drawings, Figure 2 shows a detailed configuration of the adjusting unit 20, the tracking gas inlet line 32 is a tracking gas flow meter 51, dry air inlet line 33 is dry air ( Or nitrogen gas) flow meter 52, and the discharge line of the tracer gas flow meter 51 and the dry air (or nitrogen gas) flow meter 52 is laminated and connected to the mixing tank 53. The discharge line of the mixing tank 53 is connected to the pressure reduction tank 54, the discharge line of the pressure reduction tank 54 is connected to the mixed gas injection line 27 through the valve 59 and at the same time the valve 57 ) Is connected to the gas injection / discharge line 28. In addition, the gas discharge of the adiabatic space is branched from the gas injection discharge line 28 is performed in the vacuum pumps 55 and 56 through the valve 58, the gas discharge line of the vacuum pumps 55 and 56 And configured to be connected to 29.

In such a structure, the connection lines are a kind of stainless pipe.

The operation of the leak tester for detecting leakage of the insulation space of the LNG storage tank 10 configured as described above is as follows.

First, moisture (or gas) is discharged from the first and second heat insulating parts 11 and 12 of the LNG storage tank 10 using the vacuum pumps 55 and 56.

Then, in order to remove moisture (or gas) in the LNG storage tank 10, pure dry air (or nitrogen gas) 22 is the drying device 23 and the drying air (or nitrogen gas) of the adjusting unit 20. Feed into the first and second insulation sections 11 and 12 of the LNG storage tank 10 through the flow meter 52, the mixing tank 53 and the decompression tank 54, and the gas injection / discharge line 28. do.

Moisture and other gases are removed from the first and second heat insulating parts 11 and 12 of the LNG storage tank 10 by repeating the exhaust and drying air (or nitrogen gas) injection of the insulation space several times. When it is done, a test for leak detection of the hermetic space is started.

In detail, the tracer gas 21 such as ammonia and dry air (or nitrogen gas) 22 are introduced into the tracer gas flow meter 51 and the dry air (or nitrogen gas) flow meter 52 of the adjusting unit 20. do. The flow meter is a device for adjusting the injection amount of gas, and in particular, it is possible to match the mixing ratio of the tracer gas and dry air (or nitrogen gas). Therefore, the tracer gas and the dry air (or nitrogen gas), the ratio of which is determined through the flow meters 51 and 52, are injected into the mixing tank 53. The mixing tank 53 is a device for uniformly mixing the dry air (or nitrogen gas) and the tracer gas used by mixing in the tracer gas, the tracer gas and dry air (or nitrogen gas) is here Uniformly mixed at The gas mixed through the mixing tank 53 is introduced into the pressure reduction tank 54. The pressure reduction tank 54 is a device for constantly adjusting the injection pressure of the mixed gas (tracking gas + dry air).

Accordingly, the mixed gas, which is controlled under reduced pressure through the pressure reducing tank 54, is first and second through the gas distributor 13 and the plurality of inlets 14 in the LNG storage tank 10 along the mixed gas injection line 27. It is injected into the heat insulation part 11 (12). At this time, the mixed gas (which is heavier than actual air) is concentrated in one direction in the first and second heat insulating parts 11 and 12 through the gas distributor 13 and the inlet port 14 formed in the LNG storage tank 10. It is to be injected evenly, without the valve 59 of the adjusting portion 20 is open (OPEN), the valve 57, 58 is closed (CLOSE).

Therefore, when the gas mixture of the appropriate concentration is filled in the heat insulating part to be inspected in the first and second heat insulating parts 11 and 12 of the LNG storage tank 10 which is the hermetic container, the leakage test is started. As described above, when the ammonia tracking gas is used, the reaction reagent is applied to the outer surface of the adiabatic space of the LNG storage tank 10 and then reacted with the ammonia gas leaking through the leaked place. The leak location is detected by the presence or absence of discoloration, and when helium or halogen tracer gas is used, the helium or halogen tracer gas leaking through the leak that may be present in the welded part of the outer surface of the membrane is detected using a helium or halogen tracer gas detector. It is.

Meanwhile, vacuum pumps 55 and 56 are connected to the decompression tank 54. The vacuum pumps 55 and 56 are devices for discharging the gas introduced into the airtight space, and the LNG storage tank 10 Gases injected into the first and second heat insulating parts 11 and 12 are discharged to the ammonia dilution tank 30 through the vacuum pumps 55 and 56 and the gas discharge line 29. At this time, the valves 57 and 59 are closed, and the valve 58 is opened so that the gas filled in the first and second insulation units 11 and 12 vibrates through the gas injection / exhaust line 28. It is discharged to the pumps 55 and 56. When the ammonia dilution tank 30 uses ammonia as the tracer gas, after the inspection is completed, the ammonia dilution tank 30 is used to completely dissolve the ammonia gas discharged into the air to prevent air pollution by ammonia. When helium or halogen gas is used as the tracer gas, the tracer gas can be exhausted directly into the atmosphere without using the ammonia dilution tank 30.

In addition, the safety valve tank 40 is to be installed for the safety when the pressure of the heat insulating portion rises above a certain reference value to adjust the water level or to prevent overpressure by using lead.

However, the leak inspection apparatus using the conventional tracer gas configured as described above has the following problems.

Both the tracer gas flow meter and the dry air (or nitrogen gas) flow meter are used as a FLOAT TYPE flow meter, which may be damaged or injured due to unstable gas pressure changes, and it is difficult to adjust the gas concentration precisely due to the difficulty of fine pressure adjustment. When the tracer gas flow meter is laminated in the middle of the dry air (or nitrogen gas) flow meter discharge line and the pressure of the tracer gas used in a small amount is lower than that of the dry air (or nitrogen gas), the dry air having a relatively high pressure is used. (Or nitrogen gas) may flow back into the tracer gas flowmeter.

In addition, conventionally, only a gas discharge and injection device for a large-capacity airtight test such as a heat insulation space of an LNG storage tank in an LNG carrier or an LNG take-up base is manufactured, and a medium / small capacity (a part of a large capacity storage tank is manufactured by a neck cup) Economically and systemically difficult to apply to airtight containers

In addition, the conventional inspection apparatus for the small-capacity hermetic container was exhausted by using only a vacuum pump without using a special device, and then the pure trace gas was injected into the hermetic container to perform the inspection. However, this method is expensive by injecting pure ammonia, helium or halogen gas, and the accuracy and safety of the test cannot be secured.

In addition, the conventional connection line was used by welding and assembling stainless steel pipes to each other, which not only increases the material cost but also causes welding and assembly work for installation, thereby increasing additional cost, manpower and time, and also on-site There was a problem in that it interferes with the pipeline installation of LNG carriers, delaying the entire work process.

The present invention was devised to solve the above problems, and an object of the present invention is to provide a test for leakage of a neck cup used for a large-capacity airtight test such as an insulation space of an LNG storage tank of an LNG carrier or an LNG carrier. The present invention provides a leak inspection apparatus using tracer gas suitable for leak testing of an airtight container.

Another object of the present invention is to provide a leak detection apparatus using a tracer gas that enables a leak test in a medium and small capacity airtight container by using a mixed gas of tracer gas and dry air (or nitrogen gas).

Still another object of the present invention is to provide a leak inspection apparatus using a tracer gas which has a compact structure so that the structure is simple to move and easy to manage.

In order to achieve the above object, the present invention provides a device for inspecting leakage of a partial neck cup or a medium / small capacity airtight container of an LNG storage tank insulation space of an LNG carrier or a LNG takeover base, and the predetermined container of the airtight container to be inspected. The control unit is connected to the gas injection line, gas exhaust line and safety valve line to inject or discharge the gas, and dry air (or nitrogen gas) which is supplied to the reduced pressure and mixed tank by receiving the dry air or nitrogen gas and controlling the injection amount. ) Digital flow meter, tracer digital flow meter that receives tracer gas and adjusts injection volume and delivers it to decompression and mixing tank, and dry air (or nitrogen) transferred from the dry air (or nitrogen gas) digital flow meter and tracer digital flow meter Gas) and the tracer gas, and the pressure of the mixed gas is kept constant so that the mixed gas The decompression and mixing tank to be transferred, the vacuum pump for discharging the gas injected into the hermetic container, the gas discharge line connected from the vacuum pump, and the safety valve line connected from the adjusting unit are laminated and connected to the dilution and pressure of the tracer gas. It is characterized by including the neutralization tank to perform a safety action for.

1 is a schematic configuration diagram of a leak inspection apparatus for detecting a leak in a LNG storage tank of a conventional LNG carrier;

2 is a configuration diagram showing in detail the adjustment unit of FIG.

3 is a block diagram of a leak inspection apparatus according to the present invention,

4 is a detailed configuration of the pressure reduction and mixing tank according to the present invention,

5 is a detailed configuration diagram of the neutralization tank according to the present invention,

6 is a detailed configuration diagram of the operation unit according to the present invention.

Explanation of symbols on the main parts of the drawings

100: adjustment unit 200: neck cup

300: dry air (or nitrogen gas) digital flow meter

400: trace gas digital flow meter

500: decompression and mixing tank 600: neutralization tank

700: vacuum pump

Hereinafter, on the basis of the accompanying drawings will be described in detail the configuration and operation of the present invention.

3 is a block diagram of a leak inspection apparatus according to the present invention.

The control unit 100 is provided with a main control valve for controlling the entire system, and can manage not only the entire inspection but also the gas injection and exhaust in one place, and the detailed structure thereof will be described later.

200 is a neck cup (MOCK-UP) formed by cutting a part of the insulation space of the airtight container for the leakage test, such as LNG storage tank, it can be carried out the airtight inspection only by inspection of the insulation space of the neck cup 200. In addition, the first heat insulating part 210 and the second heat insulating part 220 are configured to have a space sealed inside the neck cup 200.

The gas injection line 110 of the adjustment unit 100 is sealedly connected to the gas inlet 230 formed at a predetermined position of the neck cup 200, the gas exhaust port 240 formed at another predetermined position of the neck cup 200. And a gas exhaust pipe 250 is connected to the adjustment unit 100 through the gas exhaust line 120 and the safety valve line 130, respectively.

In addition, the dry air (or nitrogen gas) digital flow meter 300 and the tracer digital flow meter 400 are connected to the decompression and mixing tank 500 through lines 310 and 410, respectively, and the decompression and mixing tank ( The mixed gas discharge line 510 of 500 is connected to the adjusting unit 100.

In addition, the safety valve line 150 of the adjustment unit 100 is connected to the neutralization tank 600, the gas discharge line 160 of the adjustment unit 100 through the small vacuum pump 700 and the safety valve It is configured to be connected to the neutralization tank 600 through a line 610 laminated with the line 150.

Reference numeral 140 denotes a pressure gauge, 131 and 170 a concentration meter, 121 a pressure gauge, 320 and 420 a needle valve, and 151 and 710 a cock valve.

Figure 4 shows a detailed configuration of the decompression and mixing tank 500 according to the present invention, a plurality of through holes 411 is provided in the tracking gas inlet line 410 extending into the cylindrical body 520 To facilitate mixing of the dry air (or nitrogen gas) with the tracer gas and to shorten the mixing time. Such a structure is intended to allow the tracer gas which is relatively smaller than the dry air (or nitrogen gas) to be evenly dispersed. In addition, a dry air inlet line 310 is connected to the inside of the main body 520, and the mixed gas discharge line 510 is connected to a side of the main body 520.

5 is a detailed configuration diagram of the neutralization tank 600 according to the present invention, the neutralization tank 600 is a conventional ammonia dilution tank (see Fig. 1; 30) and the safety valve tank (see Fig. 1; 40) It was produced together. Its configuration consists of a cylindrical body 650, an injection line 610 in which the safety valve line 150 and the gas discharge line 160 are laminated, an exhaust port 620 for discharging gas, and a water level in the tank. The ruler 630 and the measuring tube 640 is composed of.

6 is a detailed configuration diagram of the adjustment unit 100 according to the present invention, the gas discharge line 510 discharged from the pressure reduction and the mixing tank 500 through the first needle valve 101 gas injection line 110 At the same time it is connected to the concentration measuring instrument 170 through the second needle valve 102, the gas exhaust line 120 is connected to the gas discharge line 160 through the first cock valve 103 , The safety valve line 130 is connected to the line 150 leading to the neutralization tank 600 through the second cock valve 105 and at the same time connected to the pressure gauge 141 through the fourth needle valve 106. .

In addition, the line 110, 120, 130, 150, 160, 310, 410, 510 according to the present invention is composed of a non-combustible flexible high pressure hose.

Reference numeral 104 denotes a third needle valve.

The operation of the present invention configured as described above will be described.

First, to remove moisture (or gas) present in the neck cup 200 of an airtight container (eg, an LNG storage tank) including an inner sealing space such as the first heat insulating part 210 and the second heat insulating part 220. The moisture or other gas in the neck cup 200 is exhausted through the gas exhaust port 240 and the gas exhaust lines 120 and 160 using the vacuum pump 700.

And only pure dry air (or nitrogen gas) is injected into the neck cup 200. Accordingly, the dry air (or nitrogen gas) is a gas inlet 230 through the gas injection line 110 through the dry air (or nitrogen gas) digital flow meter 300, the pressure reduction and mixing tank 500 and the adjusting unit 100. ) Is injected. In addition, when all the moisture or other gas in the neck cup 200 is removed through the process of exhausting moisture or other gas into the neck cup 200 and injecting dry air (or nitrogen gas), a full-scale airtight inspection is performed. In order to inject a mixed gas of a tracer gas and dry air (or nitrogen gas) in a predetermined ratio into the airtight space of the neck cup 200.

In detail, a tracer gas such as ammonia (or helium or halogen gas) and dry air (or nitrogen gas) are injected into the tracer gas digital flow meter 400 and the dry air (or nitrogen gas) digital flow meter 300. . The flow meter is a digital flow meter, and precisely adjusts the injection amount of gas so that the mixing ratio of the tracer gas and the dry air (or nitrogen gas) injected into the decompression and mixing tank 500 is accurate. Trace gas and dry air (or nitrogen gas) discharged through the flowmeters 300 and 400 are injected into the decompression and mixing tank 500 through the respective injection line 310 and the injection line 410. The pressure reduction and mixing tank 500 is a tank for uniformly mixing the tracer gas and dry air (or nitrogen gas), and uniformly discharging the mixed gas pressure, in particular the tracer gas injection line 410 ) Is provided with a plurality of through-holes (411) to facilitate the mixing of tracer gas to dry air (or nitrogen gas), and shortens the mixing time. Such a structure is intended to allow the tracer gas which is relatively smaller than the dry air (or nitrogen gas) to be evenly dispersed. The mixed gas is discharged to the adjusting unit 100 through the mixed gas discharge line 510.

The mixed gas discharged through the gas discharge line 510 is injected into the gas injection line 110 through the first needle valve 101 of the adjusting unit 100. Therefore, the mixed gas is injected into the neck cup 200 through the gas inlet 230. When the mixed gas is filled in the sealing space in the neck cup 200 through the above process, it is detected whether the neck cup 200 is leaked. In case of using ammonia as the tracer gas, the reaction reagent is applied to the outer surface of the neck cup 200, and the leak position is detected by the discoloration of the reaction reagent reacted with the ammonia gas leaking through the leaked place. do. In addition, when helium or halogen gas is used as the tracer gas, helium or halogen tracer gas leaking through the leakage of the welded portion of the outer surface of the neck cup 200 is detected using a helium or halogen tracer gas detector.

When the leak test is completed as described above, the mixed gas introduced into the neck cup 200 is discharged to the adjusting unit 100 through the gas exhaust pipe 121 and the gas exhaust line 120. The discharged gas is sucked into the vacuum pump 700 through the first cock valve 103 and the line 160 of the adjusting unit 100, and the mixed gas injected into the neck cup 200 is the vacuum pump 700. Will be exhausted by the operation of. Therefore, the mixed exhaust gas discharged through the vacuum pump 700 is introduced into the neutralization tank 600. The tracer gas (ammonia) in the mixed gas injected into the neutralization tank 600 is diluted in the neutralization tank 600 and discharged through the exhaust port 620.

In addition, the gas discharged through the gas exhaust port 250 of the neck cup 200 is introduced into the neutralization tank 600 through the safety valve line 130 and the second cock valve 105 of the adjustment unit 100, When the pressure of the mixed gas injected into the neck cup 200 rises above the prescribed value, it serves as a safety device to protect it.

As described above, the present invention miniaturizes the flow meter, the pressure reducing and mixing tank, the vacuum pump, and the neutralizing tank to be suitable for the leakage inspection of medium and small capacity airtight containers, and prevents the pipe installation process by using a nonflammable and flexible high pressure hose. Without any special welding and installation work, stainless steel pipes can reduce material costs, and flexible, non-flammable, high-pressure hoses make it easy to connect each site.

In addition, by installing the main valve to control the flow rate in this unit to control the entire inspection and control of gas injection and exhaust in one place, compared to the conventional control room, which was difficult to move due to the large volume and weight. It is easy and easy to change the individual inspection device to be suitable for the site at all times.

Therefore, according to the present invention, since the gas is easily discharged and injected even in the medium and small-capacity airtight containers that have been difficult to inspect in the past, trace gas for the airtight container which has not been easily performed due to the difficulty of gas injection and discharge in the past There is an advantage that the leak test is easily performed.

Claims (5)

In the apparatus for inspecting the leakage of the part neck cup of the LNG storage tank insulation space of the LNG carrier or LNG receiving station or the airtight container of medium and small capacity, An adjusting unit connected to a predetermined portion of the hermetic container to be inspected by a gas injection line, a gas exhaust line, and a safety valve line to inject or discharge gas; A dry air (or nitrogen gas) digital flow meter which receives the dry air or nitrogen gas and adjusts the injection amount to be transferred to a reduced pressure and a mixing tank; A tracking gas digital flow meter which receives the tracer gas and adjusts the injection amount to transfer the decompression and mixing tanks; A reduced pressure that mixes the dry air (or nitrogen gas) and the tracer gas transferred from the dry air (or nitrogen gas) digital flow meter and the tracer gas digital flow meter, and keeps the pressure of the mixed gas constant and transfers the mixed gas to the adjustment unit. And a mixing tank; A vacuum pump for discharging the gas injected into the hermetic container; And A neutralization tank connected to the gas discharge line connected from the vacuum pump and the safety valve line connected from the control unit to perform a safety action on the dilution and pressure of the tracer gas; Leakage inspection device using a tracking gas, characterized in that configured to include. The method of claim 1, wherein the adjustment unit A first needle valve for regulating that the mixed gas discharged from the pressure reducing and mixing tank is connected to a gas injection line connected to the hermetic container to be inspected; A second needle valve for controlling the concentration of the mixed gas; A first cock valve for intermittently connecting the gas exhaust line to the vacuum pump so that the mixed gas of the hermetically sealed container is discharged; And And a second cock valve for controlling the safety valve line connected to the hermetic container to be connected to the neutralization tank. The method of claim 1, wherein the pressure reduction and mixing tank Cylindrical body; A dry air inlet line introduced into the body; A porous tracking gas inlet line introduced into the body and forming a plurality of through holes; And A gas discharge line formed at a side of the main body to discharge the mixed gas to the adjusting unit; Leakage inspection device using a tracking gas, characterized in that consisting of. According to claim 1, wherein the neutralization tank Cylindrical body; An injection line connecting the safety valve line and the mixed gas discharge line to the main body; An exhaust port for discharging the diluted tracer gas to the outside of the main body; A ruler installed at one side to detect the water level in the main body; And A measuring tube 640 installed outside the main body corresponding to the ruler; Leakage inspection device using a tracking gas, characterized in that consisting of. The method of claim 1, The gas injection line, gas exhaust line, safety valve line and other lines connected to the airtight container in the adjusting unit is composed of a non-flammable, flexible high-pressure hose, the leakage inspection device using a tracer gas.