CZ35593U1 - System for monitoring leaks of wastewater from a double-skin sewer in real time - Google Patents

Description

System for monitoring the leakage of wastewater from the double-skin sewer in real time

Field of technology

The technical solution relates to a system for monitoring the leakage of wastewater from a double-skin sewer in real time, using temperature measurement by an optical cable on the principle of Raman light scattering.

State of the art

The double-skin sewer is used in environmentally exposed areas, where a potential failure of the pipeline and leakage of wastewater into the subsoil could lead to significant environmental damage. In the case of highly environmentally exposed areas, ie in areas where groundwater resources may be degraded by receiving drinking water, additional levels of sewerage network security may be required by the competent authorities.

One of the possibilities of such security is the implementation of continuous remote monitoring of the technical condition with an online warning system for reporting a fault. However, this security is currently not comprehensively solved with the specialization in double-skin sewerage. Only partial solutions related to this issue are known.

Thus, for example, the subject of the Chinese utility model CN 209782254 U is a pressure drain (drainage) pipe with water leakage detection. The pressure pipe is located in the second drainage pipe, on which the measuring cells are located at certain intervals. When pressurized water leaks from the inner pipe into the drainage pipe, the drainage pipe is filled into the pressure mode. When the drainage pipe is pressurized, the leaked water enters the measuring cell, which is situated along the route of the drainage pipe, where the presence of water - leakage is detected by means of a contact sensor, and which is subsequently signaled. However, the disadvantage of this water leak detection solution is the implementation in the measuring cells, not continuously along the entire length of the pipeline. This implies the need to accurately locate the leak site by searching it additionally in the area of the relevant measuring cell, as well as the increased investment and operating costs of the measuring technology - each measuring cell must be equipped with a contact sensor.

The solution of the system of detection of water leakage from a pressurized water pipe according to the Korean patent application KR 20180102847 A based on the measurement of temperature by an optical cable (on the principle of Raman light scattering) contributes to the elimination of the above-mentioned shortcomings. The optical cable is routed next to the pipe in the protective cable, the contact of the optical cable with the leaked water is ensured by means of holes in the protective cable, provided with a filter layer. However, the mentioned system with one optical detection cable cannot be used in double-walled sewerage both from the basic point of view and due to the different construction of the cable fastening. The system for fixing the protector in patent application KR 20180102847 A, for example, cannot be applied to hold a cable in the space between a double-skin sewer.

Furthermore, in the prior art, a relatively large number of inventions deal with the issue of routing various types of cables inside sewer pipes. These are, in particular, the procedures for the additional installation of cables in existing single-skin sewer pipes. This involves the installation of a completely separate duct from the sewerage space itself, by lining the pipes with added ducts on the outside of the liner - see eg European patent EP 1271728 B1, Czech patent CZ 292760 B6, or partially separated duct protectors, which are fixed special handles (Czech published patent application PV CZ 2019-369, ie CZ 2019369 A3) or built-ins (published patent application US 20110309314 AI). However, these solutions focus only on the routing of the optical cable in the sewer. Its reason is to reduce the investment costs for networking the new area, when it is not necessary to dig a separate trench, or management coordination

-1 CZ 35593 UI of optical cable with protection zones of other networks, not for detection of water leakage from sewerage. This also results in the autonomy of the cable on the flowing medium, when there is no contact between the cable and the waste water. However, the best possible interaction with the wastewater is necessary to use the optical cable as a monitoring element. In addition, the installation of the optical cable by the above methods does not allow its placement in the space between the double-sheathed sewer.

The essence of the technical solution

To eliminate the shortcomings of the known solutions, the system contributes to a large extent to the monitoring of wastewater leakage from the double-skin sewer in real time according to the presented technical solution, using temperature measurement by optical cable on the principle of Raman light scattering. The essence of the solution lies in the fact that this system contains three optical cables run parallel to the sewer pipes. The lower cable for detecting the leakage of wastewater from the outer shell of the sewer pipe into the subsoil is loosely routed at a level of 20 to 100 mm below the lowest point of the outer shell of the double-skin sewer. The upper cable to detect the failure of the double-skinned sewer pipe by the human factor, especially during excavation work, is run at a level of 50 to 200 mm above the highest point of the outer jacket in the microprotice. The middle cable for continuous monitoring of wastewater leakage from the inner pipe into the space of the double-skin sewer is then routed in the space of the double-skin sewer at the bottom of the outer casing in bushings connected to spacers providing spacing between the inner pipe and the outer casing of the double-skin sewer. One or both ends of all three cables are fed to an evaluation unit to evaluate the signals of the monitoring optical cables at specified time intervals.

The lower and upper cables are routed along the outer jacket of the sewer pipe and in the area of the sewer manholes then just around the shaft body.

The main benefit of the technical solution lies in the fact that it comprehensively solves the monitoring of wastewater leakage from the double-skin sewer in the non-pressure mode - ie. detection of water leakage from the inner pipe to the outer protective jacket of the pipe, detection of water leakage from the outer pipe jacket to the surroundings and detection of breach of the integrity of the upper part of the outer jacket of the pipe by mechanical damage. On the other hand, the only known solution using, similarly to the presented technical solution of temperature measurement by optical cable (on the principle of Raman light scattering) is intended exclusively for detection of water leakage from single pipe in pressure mode for drinking water supply. leaked water is secured by holes in the protective cable. Its use to detect the leakage of wastewater from the double-walled sewer in the non-pressure mode (with free surface) is therefore not technically possible - eg because the system of fixing the shield according to this known solution cannot be applied to the cable in the interspace . In contrast, the system according to the technical solution solves this problem by a unique attachment to the bushings of microtubes attached to the spacers used to define the gap between the inner and outer pipes of the double jacket sewer.

Another known method of water leakage detection, in turn, is disadvantageous in comparison with the present technical solution in that the detection of water leakage is realized in measuring cells, not continuously by an optical cable along the entire length of the pipeline. This implies the need to accurately locate the leak site by searching it additionally in the area of the relevant measuring cell, as well as the increased investment and operating costs of the measuring technology - each measuring cell must be equipped with a contact sensor.

Clarification of drawings

The attached drawings serve to clarify the essence of the technical solution, where it represents:

- 2 CZ 35593 UI Fig. 1 cross section of the axis of the double-skin sewer pipe;

Fig. 2 is a longitudinal section along the axis of a double-walled sewer pipe;

Fig. 3 shows the situation of cable routing along the double-walled sewer pipe; and FIG. 4 is a diagram of an evaluation unit.

Example of technical solution

The system for monitoring the leakage of wastewater from the double-sheathed sewer in real time, using temperature measurement by optical cable on the principle of Raman light scattering (see Figs. 1 to 3) in the exemplary embodiment contains three optical cables 1, 2, 3 routed parallel to the sewer pipes. The lower cable 1 for detecting the leakage of wastewater from the outer jacket 5a of the sewer pipe 5 into the subsoil 6 is freely routed at a level of about 50 mm below the lowest point of the outer jacket 5a of the double-skin sewer. The upper cable 2 for detecting the failure of the double-walled sewer pipe 5 by the human factor, especially during excavation work, is routed at a level of about 100 mm above the highest point of the outer jacket 5a in the microprotice. The middle cable 3 for continuous monitoring of wastewater leakage from the inner pipe 5b into the interspace of the double-shell sewer pipe 5 is routed in the interspace of the double-shell sewer at the bottom of the outer shell 5a of the pipe in bushings connected to spacers 5c sewers. One or both ends of all three cables 1, 2, 3 are fed to an evaluation unit 4 for evaluating the signals of the monitoring optical cables 1, 2, 3 at predetermined time intervals.

The evaluation unit 4 (see diagram in Fig. 4) comprises a control unit 8, which consists of a laser source 9, a filter 10 for dividing the transmitted pulse and the received signal, a filter 11 for separating the Stokes and anti-Stokes components, sensitive photodetectors 12a. 12b for each component separately, and the main control unit 13. The evaluation unit 4 can kromě_ří diC unit 8 may further comprise an optical switch 14 which enables the connection of multiple paths using output 15a to 15n (wherein n is in the range 2 ^n).

The lower cable 1 and the upper cable 2 are guided along the outer sheath 5a of the sewer pipe 5 and in the region of the sewer manholes 7 then just around the shaft body.

The procedure for installing a system for monitoring wastewater leakage based on optical cables during the construction of a double-skin sewer is as follows:

After excavating the groove of the sewer path and placing the sand bed 6, the lower cable 1 is loosely laid in the sand bed 6 at the assumed bottom of the double skin sewer, i.e. the lowest point line of the outer jacket 5a of the pipe. Subsequently, the outer shell 5a is laid and completely covered. In the place above the ceiling of the outer pipe, the upper cable 2 is loosely laid in a narrow-profile flexible protector, again in the sand of the pipe.

The lower cable 1 and the upper cable 2 are routed in straight sections in the direction of the pipe axis. In the places of the inspection shafts 7, the cables are routed tightly around their body. The middle cable 3 is then installed together with the inner pipe 5b. Part of the section, or even the entire section, of the inner pipe 5b is assembled outside the ground groove and is provided with sliding spacers 5c. These spacers 5c define the position of the inner pipe 5b within the double-walled sewer. The middle cable 3 is then passed through a microtube, which is fixed to the sliding spacer sleeves 5c so that its position is about 2 cm from the outer part of the sleeve and at the same time the bottom of the outer casing 5a of the pipe. This position of the middle cable 3 results in a sufficient response to the failure of the inner pipe 5b and at the same time this solution prevents mechanical damage from the sliding spacer 5c. This system is then retracted into the outer jacket 5a of the double-skin sewer pipe

-3GB 35593 U1 so that the middle cable 3 is located at the bottom of the outer jacket 5a of the pipe. Subsequently, one end, or both ends, of all optical cables 1, 2, 3 is led to the evaluation unit 4 located at the control room of the sewerage system operator.

The cables 1, 2, 3 can also be connected in series, with at least one end of the common cable having to be fed to the evaluation unit 4.

Industrial applicability

The system according to the technical solution is intended for complex real-time monitoring of wastewater leakage from a double-skin sewer, with this monitoring including detection of wastewater leakage from the outer shell 5a of sewer pipe 5 to subsoil 6, detection of wastewater leakage from inner pipe 5b of the double-walled sewer pipe 5 and the detection 15 of the failure of the double-walled sewer pipe 5 by the action of the human factor, especially during excavation works.

Claims (3)

PROTECTION REQUIREMENTS A system for monitoring the leakage of wastewater from a double-walled sewer in real time, using temperature measurement by an optical cable on the principle of Raman light scattering, characterized in that it comprises three optical cables (1, 2, 3) routed parallel to the sewer pipes. that the lower cable (1) for detecting the leakage of wastewater from the outer jacket (5a) of the sewer pipe (5) into the subsoil (6) is freely routed at a level of 20 to 100 mm below the lowest point of the outer jacket (5a) of the double jacket sewer, upper the cable (2) for detecting failure of the double-sheathed sewer pipe (5) by human factors, especially during excavation work, is routed at a level of 50 to 200 mm above the highest point of the outer sheath (5a) in the microprotection and the middle cable (3) for continuous leakage monitoring waste water from the inner pipe (5b) to the interspace of the double-skin sewer pipe (5) is led in the interspace of the double-shell sewer at the bottom of the outer shell (5a) of the pipe in the joint bushings with spacers (5c) ensuring the spacing between the inner pipe (5b) and the outer sheath (5a) of the double-skin sewer and further that one or both ends of all three cables (1, 2, 3) are led to the evaluation unit (4) to evaluate the signals of the monitoring optical cables (1, 2, 3) at specified time intervals. Wastewater leakage monitoring system according to Claim 1, characterized in that the cables (1, 2, 3) are connected in series, at least one end of the common cable thus formed being fed to the evaluation unit (4). Wastewater leakage monitoring system according to claim 1, characterized in that the lower cable (1) and the upper cable (2) are routed along the outer sheath (5a) of the sewer pipe (5) and in the area of the sewer shafts (7) just around the shaft body.