DE19643637A1 - Leak detection device and method - Google Patents

Abstract

A collecting line (2) is permeable to leaked material, and includes a pump (3) and sensor (11) for this material. The novelty comprises a metal wire (4) along the line, the wire being connected to the negative pole of a DC voltage source. Also claimed is a method of leak detection and location. The maximum concentration of a material, which penetrates into a permeable collection line is detected and located. The novelty comprises leaking solution is electrolysed, and the gas is recovered, to detect and locate its maximum concentration in the collection line.

Description

The invention relates to a device for leak detection and leak detection on a system, in particular on a Pipeline, with a manifold, for a substance is permeable, and that with a pump and with a sensor for the fabric is connected.

The invention also relates to a method for leak detection Detection and leak detection on a system, especially on a Pipeline, where a concentration maximum of a substance, which has penetrated into a permeable manifold, detec is located and located.

DE 24 31 907 C3 is a leak detection and location system (LEOS). This system includes a collection line that is permeable to the substances to be detected. With a pump is connected to the manifold, with the after other volumes of a transport medium, e.g. B. is air, is conveyed through the manifold. At the end of At least one sensor is arranged in the collecting line the manifold detects penetrated substances. The gathering The line is near a system to be monitored, especially specially arranged along a pipeline. In the event of a leak then comes out in the system or in the pipeline leaked substance to the manifold and penetrates the manifold. It forms near the Leaks in the manifold routed there a concentration maximum of the fabric. The next time the leak is pumped recognition and location system reaches this concentration maximum to the sensor. From the period between the one the pump switches off and the sensor responds, the location of the leak can be determined.  

This known system can only be used when in the monitoring system, a substance is present, on the one hand can penetrate the manifold and on the other hand by egg a sensor is to be detected.

A device is known from EP 0 525 593 B1 with which when using the mentioned leak detection and location system (LEOS) detected leaked acid and that Leak can be located. This is possible because in the A material is attached near the manifold, which at Contact with the acid to form a detectable Substance for which the manifold is permeable, chemical responds. This material can be zinc, especially zinc wire, be. Zinc reacts with acid to form of hydrogen, with the well-known leak detection and Location system can be detected in a simple manner.

So far it is not yet possible with the well-known tasty Identifier and location system from leaked leaks solutions that can be neutral or even alkaline tect. Such a solution, which is trans ported can be, for example, salt water. In the Production of underground gas storage for natural gas must namely Frequently salt water is removed, which can contain up to 300 g of salt per Liter contains. This often requires a salt water pipe very long distances, for example to the sea will. Because salt water can damage plants, it is required to monitor these salt water pipes to a Finding and locating a leak quickly and reliably.

The invention was therefore based on the object, as such known leak detection and location system (LEOS) and that there to design associated processes so that solutions, who don't need to be angry, e.g. B. salt water, detected can be.  

The task of designing LEOS in a suitable way will be solved according to the invention in that outside the collection line is arranged along it a metal wire which with the negative pole of a direct voltage source in connection manure stands.

If a solution from the pipeline to be monitored, at for example a saline solution that comes out at one point touches the wire, electrolysis occurs there. There is caused by the metal wire, which acts as a cathode and which is connected to the negative pole of the DC voltage source is, generates hydrogen. Even small amounts of hydrogen are then sufficient to penetrate the manifold, the is permeable to hydrogen. The next time you rinse then reaches the hydrogen, which is at the location of the leak in the Manifold has accumulated to the sensor that detects the water fabric detected. The location of the leak then becomes more common Way determined.

With the invention the advantage is achieved that on a loading container or a leak can be located on a pipeline can if a solution, especially salt water, from the leak exit. The solution does not have to be acidic.

It is sufficient if the DC voltage source is a DC voltage that is less than 48 volts. You come So with a small, inexpensive DC voltage source out.

Below the manifold and the metal assigned to it wire can be arranged in a gutter. With that he will is sufficient that the leaked liquid always after a leak wetted the metal wire.

For example, the manifold and the metal wire of an absorbent material, e.g. B. sand, be surrounded. The capillary forces in the absorbent material make it safe  made sure that there is always enough leakage to the Me tall wire and consequently sufficient hydrogen produ is decorated.

For example, the manifold together with the Me tall wire in 8 a.m. to 9 a.m. position or in 3 a.m. to 4 p.m. Position along a pipe. With Such a positioning has the advantage that Rainwater in the Bo. Without causing a leak indicator that can seep away. If, on the other hand, a leak caused a Relatively large amount of liquid is released, builds up this up to the manifold so that there is a leak knows and can be located. The positioning mentioned the manifold can be used particularly advantageously, if the pipeline and the manifold in a sand bed are arranged.

For example, the manifold with the metal wire is un arranged below a pipe. This ensures security represents that liquid leaking from a leak detects the me tall wire reached.

For example, the DC voltage source can be variable. As a result, the amount of hydrogen generated can sensitivity of the system consisting of manifold and sensor be put.

To prevent the measurement results from being falsified by rainwater prevent in which salts can be dissolved become low and distributed evenly over the length of the manifold Hydrogen concentrations for the detection of a leak not considered. Only local large maxima of the water substance concentrations are regarded as an indication of a leak.

When using a gutter for the solution can this gutter has an outlet at its lowest point ben, which is designed so that the liquid entry through  Rain immediately flows through the gutter. Of the Metal wire that together with the manifold in the on trap is then not a solution covered. Only if there is a leak in the above the gutter arranged pipeline or system gets so much solution the gutter that more runs in than can run out. Thereby the metal wire is covered by the solution and it becomes what generated hydrogen that can be detected. Hereby will the advantage achieved that even in the rain no incorrect measurements may occur.

With the positive pole of the DC voltage source is at for example, a metal electrode connected to the ground to be ordered. The main advantage is achieved that even with a very long operating time only the positive metal electrode, but not the Dissolve metal wire located along the manifold can. As with the cathode protection for Me known as such Valley lines will be the negative pole of a DC chip Metal part connected to the voltage source is not corroded.

In particular, the advantage is achieved that the be on a known place in the ground arranged metal electrode, the for example, can consist of a metal rod if it badly corroded, can be easily replaced. It is consequently not required, which is attached to the manifold ordered metal wire to exchange what because of the in the Re very large length of the manifold and thus of the me tall wire would be very expensive. In addition, the Sam cable and the metal wire are often arranged underground and therefore difficult to access.

According to another example, the positive pole of the DC voltage source connected another metal wire be the metal wire connected to the negative pole spaced along the outside of the manifold along is arranged.  

The two wires don't touch. Also on the same voltage source opposite end of the wires, is not one Connection exists between the wires. For example the two metal wires run parallel to each other.

For example, the two metal wires can be made from under different metals exist. Then it is not a separate one DC voltage source required. The wires then form due to the different levels of the two metals in a voltage in the electrochemical series source. One then advantageously comes without a separate chip source.

The one metal wire can e.g. B. made of copper and the other galvanized copper. Then there is no surface changes in the metal wires.

For example, one is in at least one of the metal wires Ammeter integrated. If the leakage liquid that runs out of a leak, is electrically conductive, who which the two metal wires conduct through the leakage liquid connected and the ammeter indicates a current flow. At suitable interpretation of the voltage, the current between between 1 mA and 20 mA. Regardless of the existence of an ammeter is produced by electrolysis hydrogen produ adorned, by which a determination of the leakage location is possible is.

The current measurement has the advantage that in a short time Time can be reliably recognized whether there is a leak anywhere is available. There is a measurable current in the metal wires if a conductive liquid this connects. It is then advantageously possible that only when the ammeter registers an increase in current has a measurement to determine the location of the leak LEOS is done by flushing the manifold and on the sensor the arrival of an increased hydrogen concentration regi  is treated. It is therefore not necessary to collect the egg rinse at regular intervals. It is enough egg initiate a flushing process if the electrical measurement a leak has been indicated.

A leak can therefore be located much faster than before.

Even if no leak is found, the collecting egg should rinse with fresh air about every seven days to prevent condensation from forming in the pipe. It is also possible to use the manifold if no measurement done to seal at both ends after using dry air has been filled.

For example, at the two ends of the metal wire pairs a DC voltage source must be connected in succession, to which an ammeter is assigned. Should the two wires at a leakage location due to conductive liquid can then be connected from the measured current strengths of the Leakage location can be determined electrically when the resistance the metal wires per unit length is known. So you can the leakage location twice, electrically and with the leak detection and location system (LEOS), determine, and thus the Increase measuring accuracy.

The wires or the single wire can be through plastic tapes, e.g. B. by a braid of plastic tapes around the manifold run around, be fixed to it. This also provides mechanical protection.

The task of finding a suitable method for leak detection and leak detection on a system, in particular on a Pipeline, to specify, is ge according to the invention triggers that from a solution that leaked out of a leak is a gas by electrolysis, e.g. B. hydrogen is, the maximum concentration in the manifold, z. B. with the help of the leak detection and Or  system (LEOS), is detected and located. From the Time difference between switching on the pump of the leak detection and location system and the arrival of a con The gas maximum at the sensor then becomes the Lecka determined location.

With the device and with the method according to the invention the particular advantage is achieved that from a leak leaking solutions, especially salt water, reliably recognized and the location of the leak can be determined.

The invention is explained in more detail with reference to the drawing:

Fig. 1 and Fig. 2 show two variants of a device for leakage detection and leakage location in accordance with the invention at a salt water pipe,

Fig. 3 shows the arrangement of a manifold, which is associated with a tall wire, next to a salt water line,

Fig. 4 shows the arrangement of a manifold, the two metal tall wires are assigned, below a salt water line,

Fig. 5 shows the arrangement of a manifold, which two metal wires are associated with, in absorbent material.

Figs. 1 and 2 show a salt water pipe 1, to be detected at the leak and located. This salt water line 1 is associated with the known leak detection and location system (LEOS). LEOS consists of a per meable manifold 2 , which is laid along the salt water line 1 ent. The manifold 2 is connected to a pump 3 , with which a volume of a transport medium, which is generally dry air, is pumped through the manifold 2 at intervals. A sensor 11 is arranged at the end of the collecting line 2 . The manifold 2 is permeable to substances to be detected. If such a substance to be detected penetrates into the collecting line 2 at a specific location, a concentration maximum of the substance is formed there. During the next pumping operation, this concentration maximum is transported to sensor 11 and registered there. From the time difference between the start of the pumping process and the registration of the maximum in the sensor 11 , the location at which the substance has penetrated into the collecting line 2 is determined at a known flow speed in the collecting line 2 .

If a substance is transported in a pipe to be monitored a leakage location can occur can be reliably determined.

However, salt water cannot be recognized with LEOS alone. The device of Fig. 1 therefore provides that outside of the manifold 2 along it a metal wire 4 is angeord net, which is connected to the negative pole of a DC voltage source 5 . The positive pole of this DC voltage source 5 is connected to a metal electrode 12 , which can be arranged anywhere in the ground. For example, the metal electrode 12 can be inserted into the ground in a simple manner.

If a leak in the salt water pipe emerges 1 salt water, the metal wire 4 is at the leak location with the salt water in contact. Electrolysis then occurs, where hydrogen is formed.

The manifold 2 used is permeable to hydrogen. Therefore, the hydrogen generated by the electrolysis penetrates the manifold 2 and forms a maximum concentration at the position of the leak in the salt water line 1 . In the following pumping process, the hydrogen concentration maximum reaches sensor 11 , which is a hydrogen sensor.

The leakage location then becomes in the manner already described certainly.

The electrolysis only corrodes the metal electrode 12 connected to the positive pole. The metal electrode 12 can be exchanged in a simple manner in the case of advanced corrosion. The tall wire 4 connected to the negative pole, which is very long and difficult to access, does not corrode. It is therefore not necessary to replace the metal wire 4 even with a long operating time.

The device of Fig. 2 provides that outside the Sam melleitung 2 are arranged along it along two spaced metal wires 4 and 13 which are connected to a DC voltage source 5 .

If salt water escapes from a leak in the salt water line 1 , the two wires 4 and 13 are connected to one another by the salt water at the leak location. Electrolysis then occurs there, producing hydrogen. Otherwise, the device of FIG. 2 works like that of FIG. 1.

In one of the two metal wires 4 , for example, an ammeter 6 is integrated. Since salt water is electrically conductive, there is a conductive connection of the metal wires 4 and 13 in the area of the leak in the salt water line 1 . The current flowing through this is registered by the ammeter 6 . A current flow consequently indicates that there is a leak somewhere on the salt water line 1 .

The leak is then located using the described system (LEOS). Due to the current measurement, it is possible to dispense with regular pumping operations. Only when the presence of a leak through the current flow has been known is a pumping process initiated to determine the location of the leak. In addition, however, the salt water line 1 can be switched off immediately after the flow of current in the ammeter 6 in order to avoid further leakage of salt water. The location of the leak then serves to determine the location where a repair is necessary.

If the DC voltage source 5 is variable, the amount of hydrogen generated by electrolysis can be adjusted to the sensitivity of the system (LEOS).

Fig. 3 shows a cross section of the manifold 2 in the 8 o'clock position to the salt water pipe 1. As shown in FIG. 1, the collecting line 2 is assigned a metal wire 4 . This metal wire 4 is attached to the Sam melleitung 2 with plastic tapes 7 . The manifold 2 with the talld Me wire 4 is in absorbent material 10 , z. B. embedded in sand, which extends to the salt water pipe 1 and surrounds it at least below. Rainwater seeps through the sand bed without waterlogging in the ground. Only in the event of a leak in the salt water line 1 does the then emerging large amount of water accumulate up to the sensor hose 2 .

Fig. 4 shows in a cross-section the manifold 2 by half of the salt water pipe 1. The collecting line 2 is assigned two metal wires 4 and 13 , as shown in FIG. 2. For this purpose, they are fastened to the manifold 2 with plastic strips 7 . Below the manifold 2 and the metal wires 4 and 13 , a collecting trough 8 is arranged, which has an outlet opening 9 . Should rainwater get into the gutter 8 , this will immediately flow through the outlet opening 9 . If there is a leak in the salt water line 1 , however, so much salt water gets into the gutter 8 that the water level in the gutter 8 reaches the metal wires 4 and 13 relatively quickly, so that hydrogen is generated. In this way, incorrect measurements due to rainwater are avoided.

Fig. 5 shows an arrangement of a manifold 2 and metal wires 4 and 13 , which are surrounded by an absorbent material 10 . This absorbent material 10 absorbs the salt water escaping from a leak and, like the gutter 8 , causes the salt water to be in contact with the metal wires 4 and 13 for the generation of hydrogen for as long as possible.

The variant of Fig. 3 can, as shown in Figs. 2, 4 and 5, have a manifold 2 , the two metal wires 4 and 13 are assigned. Likewise, the variants of FIGS. 4 and 5, as shown in FIGS. 1 and 3, may have a collecting line 2 to which only one metal wire 4 is assigned.

The voltage at the voltage source 5 can also be set such that the hydrogen production in rainwater is not sufficient for a measurable concentration maximum in the collecting line 2 . Only when salt water from the salt water line 1 , which contains significantly more salts, reaches the metal wire 4 , a measurable amount of hydrogen is then generated.

With the device according to the invention, a leak in the salt water line 1 can be reliably detected and located.

Claims (13)

1. Device for leak detection and leak detection on a plant, in particular on a pipe ( 1 ), with a manifold ( 2 ) that is permeable to a substance, and with a pump ( 3 ) and with a sensor ( 11 ) for the fabric is connected, characterized in that outside of the collecting line ( 2 ) along it a metal wire ( 4 ) is angeord net, which is connected to the negative pole of a DC voltage source ( 5 ). 2. Device according to claim 1, characterized in that a collecting channel ( 8 ) is arranged below the manifold ( 2 ) and the metal wire ( 4 ). 3. Device according to one of claims 1 or 2, characterized in that the collecting line ( 2 ) and the metal wire ( 4 ) are surrounded by an absorbent material ( 10 ). 4. Device according to claim 3, characterized in that the collecting line ( 2 ) together with the metal wire ( 4 ) in the 8 o'clock to 9 o'clock position or in the 3 o'clock to 4 o'clock position on the pipeline ( 1 ) is arranged along. 5. Device according to one of claims 1 to 3, characterized in that the collecting line ( 2 ) with the metal wire ( 4 ) below a Rohrlei device ( 1 ) is arranged. 6. Device according to one of claims 1 to 5, characterized in that the direct voltage source ( 5 ) is variable. 7. Device according to one of claims 1 to 6, characterized in that a metal electrode ( 12 ) is connected to the positive pole of the DC voltage source ( 5 ), which is to be arranged in the ground. 8. Device according to one of claims 1 to 6, characterized in that with the positive pole of the DC voltage source ( 5 ) a further metal wire ( 13 ) is connected, the metal wire ( 4 ) connected to the negative pole spaced outside the collecting line ( 2 ) is arranged along it. 9. Device according to claim 8, characterized in that the two metal wires ( 4 and 13 ) are made of different metals be. 10. Device according to claim 9, characterized in that the one tall wire ( 4 ) made of copper and the other metal wire ( 13 ) consists of galvanized copper. 11. Device according to one of claims 8 to 10, characterized in that an ammeter ( 6 ) is bound in at least one of the metal wires ( 4 , 13 ). 12. Device according to one of claims 8 to 10, characterized in that to the Me tall wires ( 4 , 13 ) in succession at both ends a DC voltage source ( 5 ) can be connected, which is assigned an ammeter ( 6 ). 13. A method for leak detection and leak detection on a system, in particular on a pipeline ( 1 ), a Kon maximum concentration of a substance that has penetrated into a permeable sam line ( 2 ) is detected and located, characterized in that from a solution which has escaped from a leak, a gas is obtained by electrolysis, the maximum concentration of which is detected and located in the collecting line ( 2 ).