Sodk in the heating network. waste or irreplaceable element

The article will tell you how the UEC system works in PI pipes and how to do it correctly. The information is useful for those who want to save money and perform the installation on their own, and for those who already have experience in using such a heating network, but the remote control is out of order or of poor quality.

Ignorance of the basic principles of operation, incorrect installation of elements and inability to handle devices often lead to the fact that all good things are considered useless or useless. This happened with the system of operational remote control thermal networks: the idea was great, but the implementation, as always, let us down. The indifference of the customer, on the one hand, and the “responsible” work of the builders, on the other hand, have led to the fact that in our country, SODK works correctly at best in 50% of the constructed pipelines, and it is used in 20% of organizations. Taking Europe as an example, even not far away, let's say Poland, one can see that the incorrect operation of the remote control system is equated to an accident on the pipeline with urgent repair work. In our country, it is much more common to see a street excavated in the middle of winter in search of a place for a heat pipe break than the summer preventive work of a team of electricians. In order to make things clear, let's look at the SODK in heating networks from the very beginning.

Purpose

Pipelines of heating networks from generation to generation remain steel, and the main reason for their destruction is corrosion. It occurs due to contact with moisture, and the outer wall of the metal pipe is more susceptible to rust. The main function of the SODK is to control the dryness of the pipeline insulation. Moreover, the reason is indicated without distinction as the ingress of moisture from the outside due to a defect in the plastic pipe-shell, and the ingress of coolant on the insulation as a result of a defect in the steel heat pipe.

With the help of a special tool and SODK, you can determine:

• wetting of insulation;
• distance to wet insulation;
• direct contact of the SODK wire and a metal pipe;
• breakage of wires of SODK;
• violation of the insulating layer of the connecting cable.

Principle of operation

The system is based on the property of water to increase conductivity electric current. Used as insulation in PI pipes, polyurethane foam in the dry state has a huge resistance, which electricians characterize as infinitely large. When moisture enters the foam, the conductivity instantly improves, and devices connected to the system record a decrease in insulation resistance.

Areas of use

It makes sense to use pipelines equipped with an operational remote control system for any underground laying. Quite often, even knowing that the pipeline has a defect and there are significant losses of the coolant, it is almost impossible to determine the location of the gust visually. It is precisely because of this that winter period you either have to dig the whole street in search of a leak, or wait until the water itself washes its way out. The second option quite often ends in news bulletins with notes that cars, people or anything else that had the misfortune to be nearby failed in the city of N due to an accident on heating networks and a collapse of the earth's surface.

Does not add information content and the presence of the pipeline in the channel. Due to steam, it is not always possible to determine the point of leakage and excavation will still be significant and long. The only exception, perhaps, are large passage tunnels with communications, but they are rarely built and are very expensive.

The option of air laying of pipelines is the place where the UEC system does not make any practical sense. All leaks are visible to the naked eye and waste for additional control is useless.

Structure and structure

PI pipes used in heating networks are composed of steel pipe, polyethylene jacket pipe and polyurethane foam as insulation. In this foam there are 3 copper conductors with a cross section of 1.5 mm 2 with a resistivity from 0.012 to 0.015 Ohm / m. The wires located in the upper part are assembled into a circuit, in the position “without 10 minutes 2 hours”, the third one remains unused. The signal or main conductor is considered to be located to the right in the direction of the coolant. It enters all branches and it is by it that the condition of the pipes is determined. The left conductor is transit, its main function is to create a loop.

Connecting cables are used to extend cable outlets and connect pipelines to switching points. Usually 3 or 5 cores with the same cross section of 1.5 mm.

The switching terminals themselves are located in carpet boxes installed on the street or in the premises of pumping and heating points.

Measurements are carried out using specialized instruments. Usually it is a portable pulse reflectometer domestic production. For a stationary installation, there are also certain devices, but they are of little information and in most cases are not used.

Mounting

The assembly of all elements of the system takes place after welding of the pipeline. And if most of the work on the construction of a heating main is carried out exclusively by specialists and using technology, then with little knowledge in the field of electrics and the presence of a soldering iron, gas burner and a megohmmeter, you can do the installation of remote control yourself. For correct execution, the following sequence should be followed:

• check the integrity of the conductors in the pipe insulation by ringing;
• remove the foam to a depth of 2-3 cm, regardless of the degree of its wetting;

• carefully unwind and straighten the conductors rolled up for transportation;
• install plastic supports on the pipe, secure them with tape;
• strip conductors sandpaper and degrease;
• tension the conductors within reasonable limits (excessive tension can cause the wire to break due to the thermal expansion of the pipe, insufficient to sag the conductor and contact with the pipe);
• connection and soldering of conductors to each other (do not confuse the signal and transit wires with each other);

• press the wires into special slots in plastic coasters;
• evaluate the strength of the connection with your hands;
• degrease with a solvent and dry the ends of the shell pipes with a gas burner for subsequent installation of the coupling;
• heating the prepared ends to a temperature of 60 degrees and installing glue;
• slide the sleeve over the connection, after removing the white protective film, shrink with a burner flame;
• drill 2 holes in the coupling to assess the tightness and subsequent foaming;
• assess the tightness: a pressure gauge is installed in one hole, air is supplied through the other, the quality of the connection is assessed by holding the pressure;

• cut off the heat-shrinkable tape;
• heat the place at the junction of the sleeve / pipe-sheath and attach one end of the tape;
• symmetrically lay the tape over the joint and fasten it with an overlap;
• heat the lock plate and close the joint of the tape with it;
• seat the tape with a burner flame;
• repressurize with air as described above;
• mix foaming components A and B and pour through the hole into the cavity under installed clutch;
• when advancing the foam to the hole, install a drain plug to remove air;
• after the end of foaming, clean the surface of the coupling from foam and install a welded plug;
• after assembling the system in the pipe part, build up the conductors at the exit points;
• install carpet drawers;
• lay extended conductors in galvanized pipes from the outlet on the pipe to the installed carpet box;
• install and connect switching terminals in accordance with the project;

• connect stationary detectors;
• perform a full check with a reflectometer.

The description considers the option using heat-shrinkable sleeves, there is another type of joint insulation - electrofusion sleeves. In this case, the process will be a little more complicated due to the use of electric heating elements, but the essence will remain the same.

When performing work on the installation of the UEC system, there are also the most common mistakes. They rarely depend on who did the work - the customer himself or the builder. The most important of them is the loose fitting of the couplings. In the absence of tightness, after the first rain, the system may show wetting. The second mistake is the unselected foam at the joints: even if it looks visually completely dry, it often carries an excess of moisture and affects the correct operation of the system. After the discovery of one or another defect, one should observe the dynamics and decide when to make repairs: immediately or during the summer non-heating period.

Repair methods

Repair of the UEC system is sometimes required already at the construction stage. Let's look at a few common cases.

1. The signal wire is broken at the exit from the insulation.

Remove foam before formation required amount conductor and increase the length by soldering an additional wire (you can use leftovers from other joints). When soldering, be careful not to ignite the pipeline insulation.

1. The wire of the UEC system is in contact with the pipe.

If it is impossible to get to the point of contact without violating the integrity of the shell, the 3rd unused wire should be used to connect to the circuit instead of the defective conductor. If all conductors are unsuitable due to manufacturing defects, the supplier must be informed. Depending on its capabilities and your desire, the pipe will be replaced or repaired with a decrease in cost right on the spot. If, for any reason, contact with the supplier is not possible, self repair carried out as follows:

• determination of the place of contact;
• section of the pipe-shell;
• foam sampling;
• elimination of contact, if necessary, soldering of the conductor;
• restoration of the insulation layer;
• restoration of the integrity of the shell pipe using a repair sleeve or an extruder.

During the operation of heating networks, repairs are associated not so much with the restoration of functionality, but with the drying of the foam. The reasons can be very different: construction errors in sealing the couplings, rupture of the heat pipe, inaccurate earthworks near the pipes, and much more. If moisture gets in, the best option is to remove it to normal resistance values. This is achieved different ways: from drying with the shell open to replacing the insulating layer. The degree of dryness is controlled by a pulse reflectometer. After reaching the required indicators, the restoration of the integrity of the shell is carried out in the same way as described above.

Conclusion

In conclusion, I would like to express the hope that after reading the article, not only private traders building networks to their production building or office, but also services closely involved in the operation of pipelines. Perhaps then there will be much fewer accidents and financial losses during district heating cities.

Olga Ustimkina, rmnt.ru

ASSOCIATION OF MANUFACTURERS AND CONSUMERS OF PIPELINES WITH INDUSTRIAL

POLYMER INSULATION

Standard of the organization NP "Association of PPTIPI"

STO NP "Association PPTIPI" - * - 1 - 2012

DESIGN, INSTALLATION, ACCEPTANCE AND OPERATION

SYSTEMS OF OPERATIONAL AND REMOTE CONTROL (SODC)

PIPING WITH THERMAL INSULATION FROM POLYURETHANE FOAM

IN POLYETHYLENE SHELL OR STEEL PROTECTIVE
COATINGS

First edition

Moscow

1. General provisions. 2

2. Technical requirements. 2

3. Design of SODK. 6

4. Installation of SODK. eight

5. Acceptance of SODK into operation .. 11

6. Operation and repair of SODK. thirteen

7. Application. fourteen

8. Application. fifteen

9. Application. eighteen

10.App. nineteen

11.App. 20

12.App. 21

1. General provisions

1.1. For pipelines with thermal insulation made of polyurethane foam in a polyethylene sheath or a steel protective coating, it is mandatory to have an on-line remote control system (SODK), according to GOST clause 5.1.9.

1.2. Operational remote monitoring system (ODC) is designed to monitor the condition of the heat-insulating layer of polyurethane foam insulated pipelines and detect areas with high humidity insulation.

1.3. The basis of the operation of the UEC system is physical property polyurethane foam, which consists in a decrease in the value of electrical resistance (Riz.) with increasing humidity (in a dry state, the insulation resistance tends to infinity).

1.4. The UEC system consists of the following elements:

Signal conductors in the heat-insulating layer of pipelines, passing along the entire length of the heat pipelines.

Cables (or ready-made kits cable extension).

Terminals (mounting boxes with cable entries, terminal block and connectors).

Damage detector stationary and portable.

Portable damage locator (pulse reflectometer) or stationary.

Control and installation tester (high-voltage megohmmeter with the function of measuring the resistance of conductors).

Ground and wall carpets.

Tools for mounting SODK.

Consumables for installation of SODK.

1.5. Signal conductors are designed to transmit current or high-frequency impulse from control devices in order to determine the state of the pipeline.

1.6. The cable is designed to connect the signal conductors located in the PPU-insulation of the pipeline with the terminals at the control points.

1.7. The terminals are designed to connect control devices and connect signal conductors (cable) at control points.

1.8. The detectors are designed to determine the state of pipeline insulation and the integrity of signal conductors.

1.9. Locators are designed to search for places of pipeline insulation dampening and places of damage to signal conductors.

1.10. The control and assembly tester is designed to check the condition of the insulation (measurement of insulation resistance Riz.) and the integrity of the conductors of the control system (measurement of the resistance of signal conductors Rpr.) as individual elements pipeline, as well as the pipeline installed and ready for operation.

1.11. The carpet (metal “cabinet” of anti-vandal design) is designed to install terminals in it and protect the elements of the UEC system from environmental influences and unauthorized access.

1.12. Tools and consumables are designed to form a high-tech connection of signal conductors, cable connection, connection of terminals and detectors.

1.13. Control point - provided by the project and equipped place of access to the UEC system.

1.14. Signal line - the main or transit signal conductor of the UEC system of the pipeline between the initial and final points of control.

1.15. Signal circuit - two signal conductors of the UEC system of the pipeline between the initial and final points of control, combined into a single electrical circuit.

1.16. The performance of the SODK is assessed using a control and installation tester, by measuring the actual values ​​of the insulation resistance and the resistance of the signal conductors and then comparing them with the values ​​calculated according to the standards (see. clause 5.4. ÷ 5.7.).

1.17. By agreement with the operating organization, it is allowed to use other UEC systems, the installation, control and adjustment of which must be carried out in accordance with the relevant technical documentation of the manufacturer.

2. Technical requirements

2.1. Thermal insulation of steel pipes, fittings and parts must have at least two linear signal conductors of the UEC system. Signal conductors should be placed at a distance of 20 ± 2 mm from the surface of the steel pipe and geometrically at 3 and 9 o'clock.

2.2. For pipelines with a metal pipe diameter of 530 mm and above, it is recommended to install three conductors. The third wire is called the reserve, the pipe is oriented in the trench so that it is located at the top of the pipe at 12 o'clock.

2.3. The signal conductor is a wire made of copper wire grade MM 1.5 (section 1.5 mm2, diameter 1.39 mm).

2.4. The electrical resistance of signal conductors made of wire grade "MM 1.5" should be in the range of 0.010 ÷ 0.017 Ohm per 1 running meter of wire (at a temperature of -15 to +150ºС).

2.5. It is forbidden to use conductors in an insulating braid (except for flexible steel pipelines) and varnished wires.

2.6. Signal conductors must be led out of the pipeline through the end and intermediate elements of the pipeline with an output cable. The design and manufacturing technology of a pipeline element with a cable outlet must ensure tightness throughout the entire service life of the pipeline. For the manufacture of the above elements, it is recommended to use a special product - welded (welded) cable outlets with pre-soldered cable.

2.7. One of the conductors must be marked. The marked conductor is called the main conductor, and the unmarked conductor is called the transit conductor. The marking of the conductor is carried out either by “tinning” the entire conductor (before it is installed in the pipe), or by painting with paint the parts of one conductor protruding from the insulation on both sides of the pipe.

2.8. The reserve wire is designed to be used instead of one of the other two wires, provided they are damaged. Reserve wires at the joints of the pipeline must be connected to each other throughout the entire length of the pipeline. The reserve wire in the end and intermediate elements of the pipeline with the output cable should not be led out from under the insulation.

2.9. Flexible steel conduits use copper conductors as signal conductors. insulated wires, woven into a single bundle.

2.10. Marking of conductors for flexible steel pipelines according to the manufacturer's instructions:

A wire in a white moisture-permeable sheath, having a cross section of 0.8 mm2 (electrical resistance should be in the range of 0.019 ÷ 0.032 Ohm per 1 running meter at t = -15 ÷ 150ºС), performs the function of the main signal wire;

A wire in a green waterproof sheath, having a cross section of 1.0 mm2 (electrical resistance should be in the range of 0.015 ÷ 0.026 Ohm per 1 running meter at t = -15 ÷ 150ºС), performs the function of a transit wire.

2.11. The ODK system of flexible pre-insulated steel piping is compatible with the ODK system of pre-insulated rigid steel piping. Combination is possible through the terminal.

2.12. For the flexible steel piping system, the same instrumentation and equipment is used as for rigid steel pre-insulated piping.

2.13. Terminals must be used to connect signal conductors and connect control devices. Types of terminals, their purpose and symbols are indicated in Annex No. 1.

2.14. Installation of terminals with external connectors and IP54 and lower environmental protection class in rooms with high humidity(thermal chambers, basements of houses with a risk of flooding, etc.) is prohibited.

2.15. At control points with high humidity air, you must use terminals with protection class IP65 or higher. If at this point it is necessary to use a terminal with external connectors to connect the detector, then it is recommended to use terminals with sealed external connectors.

2.16. In order to comply with the rules for designing and installing signal conductors on pipeline branches ( items 3.8., 3.9., 4.14.) it is recommended to use tees with a universal conductor layout (see Fig. Appendix), which allows you to use one typical tee for branches, both to the right and to the left.

2.17. At control points and transits in chambers and basements of houses, NYY or NYM brand cables (3x1.5 and 5x1.5) with a conductor cross section of 1.5 mm2 and color coding lived.

2.18. At control points, connecting cables must be switched with signal conductors only through sealed cable outlets of the end and intermediate elements of the pipeline.

2.19. To extend the cable to the design or required length, it is recommended to use ready-made cable extension kits: for a three-core cable - the KUK-3 kit and for a five-core cable - the KUK-5 kit, which provide for the use of sets of heat-shrinkable tubes with an internal adhesive layer.

2.20. Connection of cores of NYM 3x1.5 cables at end control points with signal conductors in insulated pipe must be made in accordance with the color coding (see. Annex, tab.2).

2.21. The connection of the cores of NYM 5x1.5 cables at intermediate control points with signal conductors in an insulated pipe must be made in accordance with the color coding (see. Annex, tab.3).

2.22. The contact of the yellow-green conductor with the steel pipeline "grounding" must be ensured using a detachable threaded connection(a nut with a washer on a bolt welded to a steel pipeline).

2.23. To ensure continuous monitoring of the state of pipeline insulation, control should be carried out (and provided for in projects for SODK) using stationary control devices equipped with visual or audible alarms. If it is impossible to connect stationary devices (due to the lack of 220V power supply or due to the impossibility of ensuring the safety of the equipment), it is recommended to use a portable detector with autonomous power supply. A portable detector allows periodic monitoring.

2.24. The technical parameters of the applied detectors must be unified:

The threshold value of insulation resistance (Riz.) for triggering the "wet" signal must be in the range from 1 to 5 kOhm.

The threshold value of the resistance of the signal conductors (Rpr.) for triggering the “break” signal should be in the range of 150 ÷ ​​200 Ohm ±10%.

2.25. Stationary detectors must be electrically isolated along the channels, which ensures that their readings do not interfere with each other.

2.26. In order to increase the information content of monitoring the condition of the pipeline, it is recommended to use multilevel damage detectors. The presence in the detector of several levels of insulation resistance indication allows you to control the rate of insulation wetting, which characterizes the danger of a defect.

2.27. To ensure continuous monitoring, increase the efficiency of defect elimination and reduce operating costs, it is recommended to use stationary devices with the ability to connect to dispatching systems.

2.28. The dispatching system is a system for collecting data from disparate objects to a single control center, the connection between which is carried out:

Via dedicated or switched cable lines;

Via GSM connection;

By radio.

2.29. Dispatching systems must implement the following functions:

Round-the-clock monitoring of the state of objects and parameter values;

Selection and archiving of parameters with the ability to plot;

Notification of system failures by SMS and e-mail.

2.30. The basis of the equipment for data transmission installed in heating point, is a multi-functional controller. The controller is a hardware tool designed to collect information, its primary processing and transmission to the control room. Stationary PPU-insulated pipeline state detectors are connected to the controller input module. The data received from the connected devices is transmitted to the control room via the selected communication channel ( cable line, GSM - communication, radio channel), where they are processed, visualized, archived and stored. In case of emergency situations, the signal from the controller is transmitted in real-time mode to the control room.

2.31. The basic way to transfer data from the detector to the controllers are connections of the type "Dry contact" and " Current output”, which are applicable in all existing dispatching systems.

2.32. Determining the location of the malfunction of the UEC system (humidification or breakage of the signal conductor) is carried out by a damage locator, which is a portable pulse reflectometer.

2.33. The locator used to determine the location of pipeline damage must have the following characteristics:

Provide the ability to determine the type and location of defects with an error of no more than 1% of the measured length of the signal conductor;

Distance (range) of measurements not less than 100 m;

Internal memory for recording measurement results with a volume that allows you to record and store at least 20 reflectograms;

The function of information exchange with a personal computer (it is allowed to use a reflectometer with a portable printer).

2.34. Checking the state of insulation of pipeline elements should be carried out with a high-voltage megohmmeter (control and installation tester) with a control voltage of 500V. The normative insulation resistance of one element 10 m long must be at least 30 MΩ.

2.35. Continuity testing of signal wires should be carried out with a tester with the function of measuring the resistance of conductors, or using a digital multimeter.

2.36. To reduce operator errors when working with the tester, it is recommended to use testers with a digital display of the values ​​of the measured parameters.

2.37. The tester must have the function of switching (selection) of the control voltage: 250 and 500V.

2.38. The design of the carpet must meet the following requirements:

Ensure the safety of the equipment placed in it;

Ensure the convenience of maintenance and operation of SODK;

Eliminate the formation of condensate on the elements of the terminal and the penetration of moisture;

2.45. The signal conductors, detectors, terminals, locators (reflectometers), testers and cable used to monitor the condition of the pipeline must have the necessary certificates (compliance, measuring instruments, etc.) and comply with regulatory documentation.

3. Design of SODK

3.1. An obligatory component of a heating network project from pre-insulated pipes is a project for the UEC system.

3.2. The project for the UEC system is developed on the basis of the terms of reference from the operating organization and the project for laying pipelines, as well as this Standard and Manufacturers' Instructions from manufacturers of equipment for control systems. The terms of reference should indicate the installation location of stationary monitoring devices, and other special requirements.

3.3. The project for the UEC system should contain: an explanatory note, a graphic representation of the control system diagram, electrical connection diagrams.

3.4. AT explanatory note the choice of terminals and control devices - damage detectors should be justified, the locations of control points and their equipment should be justified and determined, and a calculation should be made Supplies. The note should contain a table of characteristic points, a table of control points, a cable marking table. Sample tables are listed in Appendix No. 4.

3.5. The graphic diagram of the control system should contain the following data:

Characteristic points of the pipeline (angles of rotation of the pipeline, branches, fixed supports, shut-off valves, compensators, diameter transitions, pipeline terminations, control points) corresponding to the route plan;

Control points;

table symbols all used elements of the CDS.

3.6. Based on the results of the development of the project, a specification for the components of the control system and consumables should be drawn up, indicating the points of installation.

3.7. The wiring diagram must show the order of connecting cables to the terminals (switching conductors inside the terminal) and the order of connecting cables to the signal conductors of the pipeline. The order of connection of cable conductors inside the terminal must be indicated in the passport for the connected terminal and taken as a basis for drawing up electrical circuit. The procedure for connecting cables to the signal conductors of the pipeline is indicated for each type of cable in Appendix No. 3.

3.8. The wire located to the right in the direction of water supply to the consumer on both pipelines is used as the main signal wire - it is indicated by a dotted line in the SODK diagrams during design. The second signal conductor is a transit conductor - it is indicated on the diagrams by a solid line.

3.9. All side branches must be included in the break of the main signal wire. Do not connect side branches to copper wire, located on the left along the water supply to the consumer (transit).

3.10. The design of the UEC systems must be carried out with the possibility of connecting the designed system to the existing systems of the UEC and those planned in the future.

3.11. The control point consists of: a piping element with a cable outlet, a cable, a terminal and, if necessary, a carpet and a detector.

3.12. The choice of fault detectors (portable or fixed) should be based on the ability to provide continuous monitoring (see. p.2.23, p.2.26, p.2.27). The type of a stationary detector (two- or four-channel) depends on the number of pipelines of the designed heating main. Quantity stationary of detectors is determined by the correspondence of the length of the designed pipeline with the range of operation of the selected detector. No more than one stationary detector should be installed on each signal circuit of the designed heating network.

3.13. The choice of one or another type of terminal depends on the purpose of the control point where this terminal is to be installed (see Fig. Appendix).

3.14. At the ends of the heating network, it is necessary to equip the end points of control, where end terminals , one of which may have an output to a stationary detector.

3.15. At the end of the pipeline, where there is no control point, the signal conductors must be looped in the end element under the metal insulation plug.

3.16. At the border of conjugated projects of heat networks at their junctions, including those intended for the future, it is necessary to provide control points and install one terminal , which allows both merging and separating the UEC system of these sections.

3.17. Intermediate control points must be provided at a distance of no more than 300 m (along the length of the signal line) from the nearest control point.

3.18. At intermediate points of control, intermediate terminals .

3.19. To improve the reliability of the UEC system, it is recommended to install terminals with protection class IP 65 and higher at intermediate control points.

3.20. For a pipeline section longer than 40 meters, it is necessary to install control points on both sides of the section: the end and intermediate control points.

3.21. At the beginning of side branches with a length of more than 40 m, it is necessary to arrange an intermediate control point, where intermediate terminal regardless of the location of other control points on the main pipeline.

3.22. The rule specified in 3.21 does not apply to the case when the side branch of the pipeline occurs in the thermal chamber in which the pipeline will be laid without the UEC system. In this case, an intermediate control point is not provided, but only a control point is set up in the chamber on the branch (see Fig. p.3.25 ÷ 3.28).

3.23. For side branches less than 40 meters long, one control point is allowed: either an intermediate control point at the beginning of the branch or an end control point at the end of the branch. The choice of the location of the control point is determined in agreement with the operating organization.

3.24. If it is necessary to install at the control points of a cable longer than 10 m, an additional control point should be installed with the installation of checkpoint terminal as close to the pipeline as possible.

3.25. In thermal chambers (and other similar objects), where the pipeline being designed will be laid without a control system, it is necessary to provide end control points and install checkpoint terminal .

3.26. In thermal chambers (and other similar facilities), where the pipeline being designed will be laid without a control system (due to the lack of pre-insulated pipeline elements), it is necessary to install pipeline end elements with a sealed cable outlet and a metal insulation plug.

3.27. When the conductors of the UEC system are connected in series at the places where the insulation ends (the passage of pipelines through thermal chambers, basements of buildings, etc.), the conductor connections must be made using a cable (or cable extension kits) and only through walk-through terminals .

3.28. In thermal chambers (and other similar objects), where the projected pipeline will be laid without a control system and branches into 3 or 4 directions, it is necessary to provide end points for control and install checkpoint terminal .

3.29. To increase the reliability of the UEC system, it is recommended to install pass-through terminals with protection class IP 65 and higher.

3.30. The choice of the type of cable used depends on the type of monitoring point: the intermediate points use a five-core cable, and the end points use a three-core cable.

3.31. The transit cables connecting the terminals can be of any length. The total length of the signal loop with the transit cable must not exceed the range of the detectors.

3.32. Installation of terminals at intermediate and end control points is carried out in ground (KNZ) or wall (KNS) carpets. The design of the carpet is regulated by the terms of reference. At the end points of the pipeline, it is allowed to install terminals in central heating stations, boiler rooms and other similar facilities without carpets.

3.33. Installing underground carpets without proper carpet sealing is prohibited.

3.34. The calculation of the amount of consumables for the installation of the UEC system is made on the basis of consumption rates. Consumption rates are indicated in Appendix No. 5.

4. Installation of SODK

4.1. Installation of the UEC system should be carried out in accordance with the scheme developed in the project and agreed with the operating organization.

4.2. Installation of SODK should be carried out by specialists who have been trained in the training centers of manufacturers of equipment for control systems and pre-insulated pipes.

4.3. Installation of SODK consists in connecting signal conductors at the joints of the pipeline, connecting the cable to the "elements of the pipeline with an output cable", installing carpets, connecting terminals to the cable, connecting a stationary detector.

4.4. Works on the installation of the UEC system, on the connection of signal conductors at the joints of the pipeline, on the extension of the cable should be carried out according to the technological instructions of the manufacturer or supplier of the UEC system components and using special tools and installation kits.

4.5. It is necessary to check the condition of the insulation and the integrity of the signal wires of the UEC system before starting the installation of the pipeline. To assess the performance of the SODK according to clause 5.4. ÷ 5.7. The purpose of the inspection before installation of the pipeline is to detect defects that may have formed during transportation, storage and handling. Each element of the pipeline must be checked.

4.6. When installing pipelines, pipeline elements must be oriented in such a way that the main signal conductor is always located to the right in the direction of movement of the coolant to the consumer both along the supply and return pipelines.

4.7. When installing pipelines, pipeline elements must be oriented in such a way that the location of the conductors is in the upper part of the joint, excluding the lower quarter.

4.8. Installation of the pipeline element with the output cable must be carried out taking into account the direction of supply of the coolant in the supply pipeline. The control arrow on the shell must coincide with the direction of the coolant supply to the consumer. On the return pipe, the installation of the pipeline element with the output cable is carried out in the direction of the coolant supply of the straight pipe.

4.9. Installation of signal conductors should be carried out after welding of the steel pipe.

4.10. Protect conductors during welding. Before using SODK devices, make sure that welding work on the pipeline is completed.

4.11. Before connecting the conductors at the joints of the welded pipeline, it is necessary to check the operability of the control system at each joint in accordance with clause 5.4. ÷ 5.7..

4.12. Connect the signal conductors at the joints in the strictly specified order: connect the main signal wire to the main one, and connect the transit wire to the transit wire. The overlap of conductors at the junction is prohibited.

4.13. The reserve conductor, used in pipelines with a diameter of 530 mm or more, is recommended to be connected at the joints of the pipeline, but not removed from the insulation, since in operation SODK systems is not activated.

4.14. All lateral branches of the pipeline must be included in the break of the main signal wire (see. Appendix). It is forbidden to connect side branches to the transit wire.

4.15. When insulating joints, the signal conductors of adjacent elements of pipelines must be connected by means of copper crimp bushings with mandatory subsequent soldering of the junction of the conductors.

4.16. Crimp bushings only with the help of special crimping pliers. It is forbidden to crimp the bushings with pliers or other similar tools.

4.17. Soldering of conductors is carried out using a portable gas soldering iron with replaceable or refillable gas cylinders or an electric soldering iron.

4.18. Solder conductors using only inactive flux and solder.

4.19. Signal conductors connected at the joints of the pipeline must be fixed in special holders (racks for fastening conductors) - at least 2 pieces per conductor.

4.20. Fasten the conductor holders at the joints to metal pipe with fastening tape. Do not fasten the holders with PVC insulating tape. It is forbidden to fasten the holders to the pipe over the conductor installed in them.

4.21. Upon completion of the insulation of joints along the entire length of the pipeline or in sections, an assessment of the performance of the SODK is carried out according to clause 5.4. ÷ 5.7.

4.22. After the completion of the installation of butt joints, it is necessary to equip the control points and equip them with equipment in accordance with the project specification.

4.23. Piping connecting cables must be marked to identify the respective pipes and cables. It is recommended to indicate the following data in the marking: the number of the characteristic point where the cable is connected, the number of the characteristic point towards which the signal conductors are directed along this cable and its actual length.

4.24. Connecting cables must be connected to the signal conductors through sealed cable outlets using sets of heat shrink tubing with an internal adhesive layer.

4.25. The connection of cable cores at control points with signal conductors in an insulated pipe must be made in accordance with the color marking (see. Appendix).

4.26. The connecting cable from the pipeline with a sealed cable outlet to the carpet must be laid in a galvanized pipe with a diameter of 50 mm. Welding (soldering) of a protective galvanized pipe with a cable laid in it is prohibited.

4.27. The laying of the connecting cable inside buildings (structures) to the place where the terminals are installed or at the place where the thermal insulation breaks (in the thermal chamber, etc.) must also be carried out in a galvanized pipe with a diameter of 50 mm, fixed to the wall with brackets. Inside buildings, the use of protective corrugated hoses is allowed.

4.28. Connecting connecting cables to the terminals at the control points must be carried out in accordance with the color marking and the operating instructions (device passport) attached to each terminal. The length of the cable must allow the terminal to be removed for measurements and repairs.

4.29. The terminals must be mounted in accordance with the instruction manual (instrument passport) attached to each terminal.

4.30. Labels (aluminum or plastic) with a marking indicating the direction of measurement according to 4.23.

4.31. Installation of stationary detectors and their connection to the terminals must be carried out in accordance with the instruction manual (instrument passport) attached to each detector.

4.32. Places of fastening of detectors at control points to the wall should be coordinated with the operating organization.

4.33. A portable damage detector and an impulse reflectometer (locator) are not permanently installed on the route, but are connected to the UEC system as needed and in accordance with the operating rules.

4.34. Each carpet must be marked after installation. Apply marking in accordance with the requirements of the operating organization. The marking indicates the number of the characteristic point at which it is installed and the project number.

4.35. After installation of the UEC system, its executive scheme should be performed, including:

Graphic representation of the location and connection of the signal conductors of the pipeline;

Designation of the locations of building and installation structures related to the pipeline being designed (houses, central heating stations, chambers, etc.);

Locations of characteristic points;

Table of characteristic points;

A table of symbols for all used elements of the SODK;

Table of marking of connecting cables or terminals;

Specification of the applied devices and materials.

4.36. Upon completion of the installation of the UEC system (work in accordance with clause 4.3.) an examination should be carried out, including:

Insulation resistance measurement for each signal conductor (signal line resistance);

Measuring the loop resistance of signal conductors (signal loop resistance);

Measurement of the length of signal conductors and lengths of connecting cables at all control points;

Recording reflectograms of signal conductors.

All the results of the changes are entered into the act of operability of the control system ( Appendix).

4.37. To check the operability of the ODK system of individual elements of the pipeline with a tester with a voltage of 500V, and to check the pipeline with a fully assembled ODK - 250V.

4.38. To avoid damage to stationary devices and distortions in the tester readings, it is necessary to disconnect stationary control devices from the AEC system during measurements.

5. Acceptance of SODK into operation

5.1. Acceptance of UEC systems should be carried out by a commission composed of representatives of:

The organization that carried out the installation and commissioning of the UEC system;

operating organization;

An organization that monitors the state of PPU insulation and the UEC system (in case the control is carried out by a third-party organization).

5.2. Upon acceptance into operation of the UEC system, the following documentation and equipment must be provided:

Executive diagram of the control system (if the mounted diagram of the control system differs from the design one, then all changes must be taken into account in the executive diagram);

Scheme of joints (on the scheme of joints, the distance between each joint should be indicated in meters, and characteristic points should also be indicated in accordance with the scheme of the UEC system);

Heating main plan on a scale of 1:2000;

Plan of the heating main on a scale of 1:500 with geodetic reference of the SODK carpets;

A letter of guarantee from a construction organization for a period of five years;

The act of operability of the control system;

Control devices (damage detectors, locators, etc.) with accessories (if any) and with technical documentation for their operation - according to the project;

The ODK system (operational remote control) is used to detect mechanical or chemical (caused by corrosion) damage to isothermal pipelines laid by air or underground. To date, it has become widespread, being used as part of the pipelines of the most for various purposes(including utilities).

To important features UEC systems should include:

• high level of automation of the damage search process;
• its continuity;
• accuracy of detection of damage sites;
• reliability and security of the system against failures under any operating conditions;
• relatively low cost of system components;
• ease of use.

The purpose of using the ODK system is:

• detection of places of depressurization of the serviced pipeline;
• detection of places of depressurization of its outer shell.

In addition, the UEC system is able to detect its own malfunctions, including

• violation of the integrity of conductors-detectors;
• poor butt connection of detector conductors;
• closing conductors-detectors on the pipe.

UEC system: principle of operation

The principle of operation of the UEC system is based on the fundamentals of pulsed reflectometry technology. In accordance with it, the conductor-indicator acts as a pulsed emitter, the pipe and the outer shell act as reflectors, and the heat-insulating layer acts as a medium with certain wave properties. It is on the constancy of these properties that the operation of the mechanism is built.

If the thermal insulation layer gets wet, it wave properties change in the direction of decreasing resistance and, as a result, increasing conductivity. This is immediately detected by special control and measuring instruments that combine the functions of a reflectometer and a megohmmeter.

An increase in the humidity of the heat-insulating layer, mounted in accordance with all the rules of an insulated pipeline, can be caused either by damage to the pipe and leakage of the medium transmitted through it, or damage to the outer shell and moisture ingress atmospheric air(as an option - soil). Either way, repairs are needed.

Modern UEC systems have several stages of operation. This makes it possible not only to detect the very fact of depressurization and establish its location, but also to determine the extent of possible damage. The detection accuracy is very high, and the error probability is zero.

UEC system: equipment composition

The standard OEC system has three technological levels

• conductor-detectors made of copper wire (wire section diameter 1.5 mm) with output cables;
• switching terminals for connecting control and measuring devices installed in carpets (special safe-type metal boxes, which are available in wall and ground versions);
• fixed or mobile monitoring devices, also referred to as "damage locators".

The structure of the UEC system is universal. This makes it easy to expand and rebuild it, providing the most complete and most effective monitoring possible. technical condition pipeline communications.

The procedure for using the ODK system is extremely simple. It includes the following technical steps:

• checking the readiness of the control and measuring device and the integrity of the conductor network (self-control);
• data removal;
• saving data for further analysis.

The frequency of control measures using the UEC system is not regulated by law and is established by operating organizations on an individual basis.

Ph.D. V.A. Polyakov, Head of UEC Service, CJSC Mosflowline, Moscow

(Review of the article by Alexandrov A.A. and Pereverzev V.L. “Operational remote control of PPU pipelines - effective remedy control or useless application?”, Heat Supply News magazine, No. 2, 2007)

Article by Alexandrov A.A. and Pereverzeva V.L. is devoted to an important and topical topic - the use of pre-insulated PPU pipelines with a system of operational remote control (ODC) in heat supply. It describes the measurement results characteristic faults on a full-scale model of a pipeline about 40 m long using two types of connecting cables. Featured big losses and pulse distortion in NYM cable compared to coaxial cable, as well as the importance of such a parameter of pre-insulated pipeline as impedance.

On the basis of the model experiments carried out in laboratory conditions, the authors express a completely unjustified opinion about the low efficiency of the systems of the UEC existing in Russia. At present, pre-insulated pipelines have been used in our country for more than 10 years. various manufacturers both domestic and foreign. Thus, in Moscow, only OJSC Moscow Heating Network Company (OJSC MTK) operates more than 600 facilities. These heating networks use both coaxial and NYM type cables. It should be noted that the set of rules SP 41-105-2002 does not contain restrictions on the use of specific types of cable, as stated in the article.

A decade of experience in operating the specified heat networks of MTK OJSC (more than 400 km), as well as more than 1,000 facilities (about 1,300 km) of Moscow United Energy Company OJSC (MOEK OJSC) confirms the effectiveness of the UEC systems used, their importance in improving reliability and efficiency of pre-insulated pipelines. Statistics for the period 1996-2006 According to the results of regular monitoring of the EPC systems of OJSC MTK facilities, it shows that their total damage, including mechanical damage and marriage of joint insulation, is 0.12 per 1 km per year, and the damage to steel pipelines is 0.013 per 1 km per year, which is much below the values ​​typical for traditional ways gaskets (0.28 per 1 km per year). According to the reviews of Moscow operating organizations, repair work on heat networks with PPU pipelines is mainly of a preventive, rather than emergency nature.

If we talk about comparing the types of connecting cables used, then, of course, the attenuation in NYM cables is higher than in coaxial cables. However, the practice and experience of operating monitoring systems with various connecting cables for 12 years have shown that the degree of signal attenuation in general does not affect the accuracy of fault localization. At the same time, the use of intermediate carpets at a distance of 250-350 m from each other, which is associated with the accuracy of measurements by the locator under the conditions of existing impedance deviations from pipe to pipe, actually nullified the effect of signal attenuation on the measurement accuracy.

It should be added that during the operation of control systems, the following features. Protective polyethylene sheath of coaxial cables with an impedance of 125 Ohm from European manufacturers, used in ABB systems, when working with them in winter time cracking. For this reason, since 1999 MTK OJSC has banned the use of these cables in its systems and required the use of NYM cables at operated facilities. The second problem is the use of the so-called end coaxial junction (or adapter) boxes used to connect cables with copper wires pipes or control devices. Such boxes are installed in chambers, basements of houses, central heating stations, boiler rooms and in Europe their use is justified and usually does not cause problems. In Russia, unfortunately, in thermal chambers under conditions elevated temperature and humidity, these elements quickly corrode and, in

within 5-7 years are destroyed, making the control system inoperable.

When comparing the types of cables under consideration, it must also be taken into account that the NYM cable is multi-core, and the coaxial cable is single-core. The UEC systems widely used in Russia have two signal conductors, while at the intermediate control point it is necessary to remove 5 conductors from the thermal insulation of the pipeline (including contact to steel pipe), while in the case of a coaxial cable, the bulkiness of the device for hermetic cable output increases significantly.

It is difficult to agree with the thesis put forward in the article about significant capital costs and maintenance costs for existing UEC systems based on the data in Table. 1. The data in the table are given without any justification and interpretation, however, real numbers can be given. The cost of the UEC system when using monitoring with detectors is 1-5% of the cost of pre-insulated pipelines. They cannot exceed the costs of the AEC system based on fixed locators (as indicated in the table), this is due to the fact that in the first case 1 portable locator (the most expensive device of the monitoring system) is used for a number of objects, while in the second case a stationary locator is installed at each object.

According to the control service of the Teplosetservis company, which monitors the objects of OJSC MTK (about 700), the cost of periodic inspection using a portable detector is about 3 thousand rubles. per year for 1 object. However, big number facilities, especially in the heat networks of OAO MIPC, is monitored using stationary detectors that have both LED status indication and access to the dispatching system. With this method of control, the cost of ongoing monitoring is sharply reduced compared to control with a portable device.

In general, the article in question is, in fact, useful in terms of discussion possible directions improving the production and use of pre-insulated pipelines. Controversial allegations about the inefficiency of the existing JEC systems, their high cost mislead specialists, especially those who do not have practical experience operation of these facilities, and are capable of causing damage to the indicated promising direction of development of heat supply.

The editors of the journal "NT" invites experts to take part in the discussion on this issue.