DE19509129C2 - Method and device for checking and monitoring the condition of pipes, containers, pipelines or the like - Google Patents

Description

The invention relates to a method and an apparatus for Checking and monitoring the condition of pipes, containers or pipelines according to the preamble of claim 1 or 2.

Monitoring of pipelines, heating lines, pipelines or the like has so far been carried out by inspection tours, such inspection walks of visual recognition possible Leakages serve.

Furthermore, it is known to use the in Piping system to determine existing pressure at suddenly occurring pressure drop further measures to lower initiate a search for possible damage. However, it is common Obviously, such monitoring methods, on the one hand, are very on the other hand, the location or the location is insufficient Show the location of a leak.

For reasons of environmental protection, flat-bottom tanks, be agreed piping or other dangerous media-carrying Provide containers with double bottoms or a double wall, whereby in the event of corrosion or the appearance of a Leaks in the false floor of the outer, second floor or the outer Wall security against leakage from inside guaranteed environmentally hazardous media. Construct due to the nature of the space between the two floors or pan dung, e.g. B. the intermediate floor and the outer bottom of a Flat bottom tanks are constantly monitored to determine can check whether the intermediate floor has a leak and then after the detection of such a leak z. B. the tank or drain the piping system and prepare for repair to be able to take.  

Such monitoring, including z. B. for steel jacket pipe routes, are known to be carried out by vacuum monitoring systems leads. For this, the space between the two floors or Apply a defined vacuum to the inner tube and steel jacket strikes, whereby by an appropriate pressure monitoring direction can be determined whether the vacuum is due to a Leaks changed. For every tank or given steel jacket pipe sections, however, is a separate vacuum monitor plant required, reducing the cost of such systems increase. Furthermore, it cannot be determined whether a determined pressure loss for leaks in the system flange connections, leaks in the outer base or Steel jacket or leaks in the intermediate floor or inside tube is due. If in doubt, must correspond with the entire tank or a piping system be emptied to check where the cause of the stuck leakage. Such leak detection is therefore extremely time consuming.

In addition, it is known on the inside of an exterior Soil, e.g. B. a double-walled tank bottom, a moni training room that receives a sensor cable that is able to absorb incoming liquids through local changes to change the dielectric constant of the sensor cable voices. To determine the respective penetrated substance as well as the location, the sensor cable with high frequency energy applied according to the pulse-echo method, whereby by means of egg ner downstream evaluation device the reflected measurement data with a previously recorded, stored normal image be compared.

By means of a constant comparison of the current, reflective ten measurement data with the stored normal image, a Lecka development or spread can be observed. Beyond that multiple leaks at different locations can be determined from will.  

The dielectric-sensi used in the above solution Tive sensor cable is expensive and the one required for evaluation Hardware complex, with problems still occurring if longer lengths or sections using the described Procedure should be monitored.

From the German usage attributed to the applicant muster G 93 18 404 is a device for determining tem peratures on or in extensive measuring objects known, whereby the device shown there is an optical-electronic measuring device used.

The known measuring device feeds egg at at least one end Nes optical fiber a laser pulse and serves the Un Examination of the radiation backscattered by the optical fiber.

Due to the given interactions, the tempera ture and the location along the optical fiber spectral and running evaluate time-dependent. Accordingly, the length coordinates of the optical waveguide corresponding temperature values be assigned.

The measuring ver shown in German utility model G 93 18 404 driving accesses the evaluation of the backscattered Raman Scattered light from an optical fiber for temperature measurement back. This temperature measurement is based on the known DTS (Distributed Optical Fiber Temperature- Sensing), in which the light of a laser is reflected in a light wave conductor is coupled. When the laser light spreads within the optical fiber there is scattering at the Molecules of the same, the intensity of the backscattered Light depending on the runtime to a predetermined extent falls off. Due to the known propagation speed of the emitted light in the optical waveguide can derive from the timed course of the intensity of the backscattered light the path traveled by the light can be determined.

Due to the interactions of laser light with opti phonons, d. H. Vibration quanta of an elastic De  formation wave in a solid, the Raman-Rück arises scattering. The intensity of the Raman backscattered light is direct on the temperature at the place where the litter is formed light dependent. In the case when laser light in the light waveguide coupled and the intensity of the Raman scatter depending on the runtime, the location-dependent current temperature distribution can be determined.

With the one shown in the German utility model G 93 18 404 Setup should be by arranging an optical fiber as a flat structure, expediently in the form of a grid network, monitoring the temperature development in landfills to be examined. The temperature values or temperature monitoring is intended to measure the geothermal gradient and the geothermal diffusivity in the area of the sealing Ba siston layer can be determined. By such a tempera door monitoring, which runs parallel below the base seal irregularities or damage to landfill dismantling be recognizable in order to then initiate measures with which one Impairment of the groundwater is prevented.

From European patent application 0 555 846 A2 is a Procedure for the detection of temperature anomalies in pipe lines known, which on fiber optic temperature sensors uses distributed temperature measurement. With this generic method or the disclosed device recourse is made to the knowledge that if e.g. B. pipelines with a liquid or gaseous medium, based on the ambient temperature, extreme temperature below cause different, at the location of the leak, due to the Temperature differences, measurable temperature anomaly present is. The determination of this temperature anomaly happens in on known way by using the mentioned fiber optics sensor cable that is exposed to laser light. The Sensor cables provided there are laid in sections, the cable sections via individual signal processing units discretely together with a host computer Act. Alternatively, one suggestion is loop-shaped overlapping sections of the sensor cables in certain sections  provide for the accuracy of the detection of the leakage location to increase. One way of determining the spread direction does not exist.

JP 4-168 335 discloses the arrangement of a fiber optic Sensor cable along a water-bearing line, on a temperature difference between the water in one too investigating pipeline and an underground or surrounding temperature is turned off. JP-56-97 841, however, discloses a selection system for determining temperature changes a liquid in a container. Outside the container has a fiber optic sensor cable, which in the Inside a liquid core with a given freezing point contains. The container and container to be monitored is included an extremely low temperature liquid gas. By doing If there is a leak, the liquefied gas occurs extremely low temperature and partial Freeze the material in the core of the sensor cable so that its optical properties, which in turn are detectable, change.

From the above, it is therefore an object of the invention known method for checking and monitoring the condition of pipes, containers or pipelines carrying media to further develop the danger of an accident due to leaking pipes or the like regardless of the temperature of the media in question can be assessed and above In addition, a recording of the direction of propagation and the Leakage amount itself becomes possible.

The object of the invention is achieved with a Ver drive the independent claims 1 or 2, the Expedient refinements or Training includes.

The basic idea of the invention is based on a gaseous medium in the room to be monitored with a difference based on the immediate environment media temperature or in the case of a local tempera  change in temperature due to evaporative cooling when a liquid medium or due to expansion cold Leaking gas leaks the surrounding environment temperature distribution at least over sections along and / or circumferentially and / or in the floor area close to the pipes, Containers, pipelines or the like, but outside of determine this enclosed media room.

If a local anomaly in the temperature distribution is determined is then concluded according to the invention of a leak and the Location, the direction of propagation and the amount of leakage from the Temperature distribution at the respective anomaly point or time Lichen change in temperature distribution on the above-mentioned anoma or the changing location of the anomaly.

By determining local anomalies in the tempera existing leakages, e.g. B. due to signs of corrosion or leaks Recognize welds or the like, so that in time Repair or other security measures are taken can.

Because the media temperature, the temperature distribution along the pipe or pipes to be monitored Pipeline as well as the related to the monitoring object further temperature is detected, it can be determined whether for example a temperature anomaly due to a leak in the media-carrying pipe itself is conditional or whether one is tight executed pipe trench Leaks in the trench with the result existent are that z. B. ground or leachate penetrates from the outside.

This configuration is also particularly advantageous reversible if, according to the invention, the temperature distribution in one Intermediate floor, e.g. B. is monitored in a flat-bottom tank. In this case it can be determined whether the outer floor is defective and the anomaly on moisture penetration or what water from the outside, or whether the mezzanine itself has a leak, through which the in the container located medium penetrates into the mezzanine space.  

By using day / night temperature according to the invention fluctuations in ambient temperature and due to existing The process can also heat large capacities be used when there is a container in a container Medium does not flow and remains in the container or tank for a long time remains.

The method according to the invention can also be used, for example Monitoring of collecting channels, the inclusion of postal and Serve communication cables or other electrical lines, are used, in which case an undesirable Penetration of foreign media into the respective collection channel is monitored.

On the device side, the fiber optic is proposed Sensor cable within a pipe trench or pipe bridge along the circumference of the tube, on the outer surface of the Pipe directly or over a predetermined distance to be arranged close.

The fiber optic sensor cable can be used d. H. the construction of a pipe trench or a pipe bridge be installed. However, since it is from an environmental point of view Existing pipe trenches or is increasingly required Monitoring something similar can be done without much effort equip existing systems with the device according to the invention tion.

It is in the spirit of the invention that this not only as in Acquaintances for the monitoring of pipes and containers, tanks, Pipelines or the like is used, the liquid or gaseous media with a, based on the immediate Environment, different media temperature, but that it is also used when liquid media are used be guided or enclosed, which when exiting on a Leak through evaporation cold to a local Lead temperature anomaly or temperature fluctuation. As well can be monitored a pipe or a pipe system, which for  Transport of gaseous, pressurized media is used if when the gas under pressure escapes due to the sudden expansion near the gas outlet a local Temperature change occurs.

For essentially horizontal pipes and pipelines or the like becomes the sensor cable below the pipes arranged.

In the latter case, several can expediently essentially parallel temperature sensors or sensor cables each parallel to the longitudinal axis of the tubes and below this spaced so that the direction of propagation and the spread of a leakage-related media leak is determinable.

Another basic concept of the invention on the device side is that the temperature sensor or the fiber optic Continuous and loop-shaped sensor cables in sections Surrounds pipes, pipelines or the like to ins special leaks in vertical sections and / or on Monitor welds or screw connections.

In the sense of the invention, it is due to particularly vulnerable people Places, namely the mentioned weld seams, screw connections, Curvatures or the like per surface section of the monitoring container or tube, several or more dense to provide arranged temperature sensors or sensor cables, so that even the smallest leaks with high spatial resolution identifi are decoratable.

In the case where trenches or enclosures are used to accommodate Tanks that are liquid-tight can be additional Temperature sensors or alternatively known level sensors in or on the side wall of the trench in question, a tub or the housing to be arranged to ver through a leak cause the degree of filling of the latter to be determined.  

With the help of the fiber optic that can be used particularly advantageously Sensor cable and the evaluation of runtime and intensity of the backscattered light, pipe sections with a Length from 5 to 20 km with a temperature resolution up to 0.1 ° K can be monitored. The spatial resolution depends on the length of the sensor cable in the range of 0.5 to 2 m, with higher Ge inaccuracies due to the continuous and loop-shaped laying of the fiber optic sensor cable can be enough.

All in all, the method according to the invention and the associated device in a cost-effective manner Current control and monitoring of the state of raw ren, containers, pipelines or the like, especially large Length expansion can be made, while still the measured values obtained by telemetric data transmission a central office can be evaluated, so that the total Operational safety of, for example, natural gas or oil pipes lines increased.

The invention will be explained below using an exemplary embodiment and with the help of FIG .

Here show:

Figure 1a is a plan view of a pipeline in a trench portion with existing leakage.

Figure 1b of the pipeline a cross-sectional view shown in Fig 1a an arrangement located in a trench..;

Figure 2 shows the arrangement of the distributed temperature sensor or sensor cable in a stretch compensation range of a longer pipe line having a flange or a weld.

Figure 3a is a position to be monitored Flat-bottom tank in Schnittdar, wherein distributed in the double bottom temperature sensors are arranged.

FIG. 3b shows the top view of the lower bottom of the double bottom tank according to Figure 3a with the laid meandering distributed temperature sensor or sensor cable. and

Fig. 4 is an exemplary representation of the sensed temperature on a portion of a pipeline with a pipeline below the mounted fiber optic sensor cable.

In the example shown in FIGS. 1a and 1b embodiment, a pipeline or a pipeline 1 is located in a pipe trench 2. This pipe trench 2 can be created by excavating earth 3 or by a separate trough-shaped body, for. B. from concrete (not shown), which in turn can be in the ground 3, are formed.

Inside the pipeline 1 there is a flowing medium 4 z. B. petroleum, the media temperature differs from the ambient temperature in the trench or the surrounding soil 3 .

As is along the Ausdeh voltage direction of the pipeline 1 is at least an elongated temperature sensor, for example in FIGS. 1a and 1b can be seen. B. a fiber optic sensor cable 5 is arranged. The sensor cable 5 is expediently located almost in the middle below the pipeline 1 .

To avoid destruction of the sensor cable 5 , this can be arranged laterally to the location of the maximum surface pressure between the pipeline 1 and the trench floor 2.1 or the soil 3 .

In order to be able to detect the direction of spread and size of the leak, 1 further sensor cables 5.1 can be arranged laterally below the pipeline.

In the case where the pipe trench 2 or a trough (not shown) for receiving the pipeline 1 are tightly sealed, further elongated, distributed temperature sensors 5.2 can be arranged at a predetermined height starting from the trench floor 2.1 on the side wall 2.2 of the trench 2 .

In the case of a z. B. corrosion-related leaks 6 , the medium 4 emerges and usually flows along the pipe or the pipeline 1 to the trench floor 2.1 .

The medium 4 , which has a different temperature with respect to the ambient temperature, leads to a local temperature peak, which can be determined with the medium 4 coming in contact with the section of the sensor cable 5 to 5.2 .

In the case where in the described embodiment as distributed temperature sensor a fiber optic sensor cable is used, a laser light source sends light pulses in this sensor cable, namely an optical fiber. That in Optical fiber backscattered light is given on a decoupled NEN point and via appropriate filters on one Detector led. This leaves a first optical filter Stokes line light is transmitted, while a second optical Filter light of the anti-Stokes line Ia passes.

The detector mentioned then generates from those supplied to it Intensities Is and Ia of the Stokes line and the anti-Stokes Line signals which are applied to a divider. By forming a ratio between the lines Is and Ia obtained voltage signals Us and Ua become interference an inhomogeneity of the light source used or others external influences due to the optical fiber are eliminated with the exception of temperature.

On the output side, the divider is in ver with a calculator bound, which depending on the duration of the radiated light and thus in relation to the length coordinate of the optical fiber temperature values determined.  

Using the computer, specific points or locations can therefore be found temperature values can be assigned to the optical fiber. The Ratio of the intensity of the Stokes line Is and the anti-Sto kes line Ia determines the respective temperature value, while the length coordinates of the optical fiber from the Running time of the backscattered light pulse can be determined.

The respective temperature measuring range depends on the used Sensor cable and is in the embodiment shown in Range between 100 and 750 ° K. According to one embodiment becomes a with a length of the optical fiber of approx. 8 km Local resolution in the range of one meter reached. At a The length of the optical fiber is up to 20 km time resolution reached 2 meters. That achieved local Resolving power can be controlled by controlling the pulse duration can be set. The temperature resolution achieved is in the Range of 0.1 ° K.

According to a further exemplary embodiment, this is possible self-calibration of the fiber optic used Sensor cable by recording changing averages over the Course of the day or depending on the ambient temperature of the pipe, the pipeline or the container. It is essential that occurring local temperature differences that on the Influence of leakages can be recognized nen. Expediently, reference temperatures can be used for this not only the ambient temperature but also the actual one Media temperature are detected so that, for. B. with containers non-flowing media about the daily routine and under consideration view of the heat capacity of the medium at a certain time score with sufficient temperature difference monitoring is carried out.

The determined temperature curve in degrees Celsius along a section of a pipeline is shown by way of example with FIG. 4, a fiber-optic sensor cable being used in an arrangement according to FIGS. 1a and 1b. A locally increasing temperature profile can be seen at a distance of 250 meters from the origin of the coordinate, this peak being due to a leak.

With the help of FIG. 2, the arrangement of the distributed temperature sensor or the fiber-optic sensor cable used in the exemplary embodiment is to be explained in a U-shaped section for temperature compensation of a longer pipeline, such as used in heating lines.

The heating line 10 accordingly has horizontal sections 10.1 and vertical sections 10.2 . In the area between two vertical right sections 10.2 there is another horizontal section 10.1 , which has a flange 11 or a weld. With the exception of the horizontal section in the region of the flange 11, the sensor cable 5 is located essentially along and below half of the heating line 10 on all other horizontal sections 10.1 .

In the area of the vertical sections 10.2 and in the horizontal region of the flange section, the sensor cable 5 is screw-shaped in a line or loop, circumferentially surrounding the heating line 10 . The number of loops or turns is increased in the flange area, so that reliable detection of even the smallest leaks is ensured, in particular at the location of the flange 11 or at a weld.

Of course, sensor cables 5 can also be arranged in the other sections 10.1 in a helical or loop-like manner encompassing the heating line 10 .

FIG. 3a shows another embodiment of the procedure, in particular for monitoring a tank or container 20 flat bottom.

The tank or flat bottom container 20 is filled with a medium 40 and has a double bottom 50 , consisting of inner bottom 51 and outer bottom 52 . A continuous or meandering sensor cable 60 is expediently arranged in the double floor space 50 on the inside of the outer floor 52 .

Expediently, the outer bottom 52 can have a slight gradient G, the speed of propagation of the medium penetrating through a leak 70 and thus the amount from the known distance of the sensor cable 60 and the gradient G being ascertainable.

FIG. 3b shows in basic representation, the arrangement of a sensor cable 60 as a loop meandering, which for example (not shown) by means of brackets on the outer bottom 52 and the inside of the intermediate bottom of a tank is arranged directed 20.

Since it can be assumed that the environment of the tank 20 is at a different temperature than the medium 40 in the tank 20 , it can be recognized not only whether there is a leak 70 in the inner bottom 51 , but also corrosion and leaks in the outer bottom 52 with the Consequence of the intrusion of z. B. Groundwater or rainwater can also be found.

In this embodiment, therefore, a monitoring room is formed which receives the sensor cable 60 in order to determine local temperature anomalies in the monitoring room, so that conclusions can be drawn about penetrating media. Due to the selected method, several leaks can be detected at different locations at the same time.

According to a further embodiment, the langge stretched temperature sensor or the sensor cable by means of a Rohrmolch in the interior z. B. a sewage pipe and relocated. In this embodiment, it can be determined whether through cracks and other leaks in the waste water serkanal groundwater penetrates from the outside, so that targeted Refurbishments can be made.  

The previous embodiments show that with the inventive method and the associated device On the one hand, it can be monitored whether a liquid or gas shaped medium, which is located in a media room, leaks due to leakage or whether a foreign medium in the a container or pipeline or the like Media room occurs in an undesirable manner.

Claims (5)

1. A method for checking and monitoring the condition of media-carrying pipes, containers or pipelines by determining the ambient temperature distribution at least over sections along and / or circumferentially and / or the floor area close to the pipes, containers or pipelines, but outside the media space enclosed by them , by means of an elongated fiber optic temperature sensor for distributed temperature measurement, where a leakage is concluded in the case of a local anomaly in the temperature distribution, characterized in that the direction of propagation and the amount of leakage result from the changing temperature distribution at the respective anomaly point or changing location of the anomaly released evaporation or expansion refrigeration of gaseous media, which otherwise have an approximately the same temperature in relation to the environment, can be determined. 2. Procedures for checking and monitoring the condition of media-carrying pipes, containers or pipelines Determine the ambient temperature distribution at least above Sections along and / or circumferentially and / or the Bodenbe rich close to the pipes, vessels or pipelines, however outside of the media space enclosed by these, by means of an elongated fiber optic temperature sensor for distributed temperature measurement, where a local anomaly in temperature is found distribution is inferred about a leak, characterized, that the direction of propagation and the amount of leakage from the changing temperature distribution at each anomaly point or changing location of the anomaly due to free evaporation or expansion cold gaseous Media that otherwise approx have the same temperature, can be determined by meh rere, essentially parallel sensor cables each parallel to the longitudinal expansion of the pipes or the like and are laterally spaced below this. 3. The method according to claim 1 or 2, characterized, that to determine the ambient temperature distribution in at known fiber optic, with laser light struck, sensor cable is used and in known per se Way a runtime and intensity evaluation of the Rückge Scattered laser light takes place, the location, the spread direction and the amount of leakage from the runtime and the Intensity evaluation at the respective point or changing Location of the anomaly is determined. 4. Device for performing the method according to a of claims 1 to 3, characterized,  that the or the fiber optic (n) sensor cable at essentially Chen horizontal pipes, containers or pipelines is (are) arranged below this. 5. Device for performing the method according to Claim 2, characterized, that the parallel sensor cables grind on one side are connected so that the laser signal on and off coupling can take place in a single place.