Design of sodk. UDC system for PPU pipes as a heating main maintenance tool Installation manual for the UDC system polystroy
The operational remote monitoring system (ORMS) is designed to monitor the condition of the thermal insulation layer of polyurethane foam (PUF) of pre-insulated pipelines and detect areas with high insulation moisture. An increase in the humidity of thermal insulation can be caused either by moisture penetration through the outer polyethylene shell of the pipeline, or due to coolant leakage from steel pipeline due to corrosion or defects welded joints. The absence of a UEC system for ductless installation entails the possibility of corrosion of the full cross-section of the pipeline in the area of the leaky joint and contradicts the requirements for the safe operation of heating networks.
1 . Composition of the SODK system
The UEC system includes:
- Signal copper conductors in the heat-insulating layer of pipelines running along the entire length of the heating network:
Main signal conductor (conditionally tinned);
Transit conductor
- Terminals for connecting devices and switching signal conductors at control points.
- Cables for connecting signal conductors in insulated pipes with terminals at control points, as well as for connecting signal conductors in pipeline sections where non-insulated pipeline elements are installed ( shut-off valves etc.), through elements with sealed cable outlets.
- Detector (stationary or portable).
- Damage locator.
Monitoring the condition of pipeline insulation should be carried out using stationary or portable detectors.
The state of the SODS should be assessed according to the following parameters:
1. Integrity of signal conductors, forming in in good condition closed electrical circuit (loop).
2. Insulation resistance between signal conductors and steel pipeline.
Signal conductors must be installed inside the foam insulation of each pipeline. The resistance of the signal conductors should be in the range of 0.012 - 0.015 Ohms per linear meter.
To switch signal conductors and connect control devices, you must use terminals following types:
■ end terminal - at control points at the ends of the pipeline;
■ end terminal with access to a stationary detector - at the control point at the end of the pipeline, in which a stationary detector is provided;
■ intermediate terminal - at an intermediate pipeline control point;
■ double end terminal - at the control point at the project boundary;
■ combining terminal - at those control points where it is necessary to combine two (three) pipeline sections into a single loop;
■ pass-through terminal - for connecting connecting cables in places where polyurethane foam insulation is broken (in thermal chambers, in the basements of houses, etc.) and with a connecting cable length of more than 10 meters.
Determining the location of a fault in the ODS (moistening or breakage of the signal conductor) is carried out by a fault locator, which is a pulse reflectometer.
Damage locator:
- must provide the ability to determine the type and location of defects with an accuracy of at least 1% of the measured length of the signal conductor;
- have a measurement range of at least 3000 m;
- To record measurement results, the locator must have an internal memory for recording and storage with a capacity of at least 20 reflectograms and the ability to exchange data with a personal computer. It is allowed to use the reflectometer with a portable printing device.
2. Rules for designing UEC systems
The project of an operational remote control system includes:
- explanatory note
- specification of equipment used (including materials)
- general instructions, including a list of documentation for commissioning the control system, marking of carpets and terminals and requirements for installation of the control system
- remote control circuit
- heating network installation diagram
The design of the UEC system should include:
- graphical representation of the signal conductor connection diagram
- characteristic points corresponding to the wiring diagram:
Branches from the main trunk of the heating main (including descenders)
Turning angles
Fixed supports
Diameter transitions
Control points (ground and wall carpets)
- table of data on characteristic points indicating parameters:
Point numbers
Pipe diameter on site
Pipeline length between points according to project documentation(for supply and return pipelines)
Length of the pipeline between points according to the joint diagram (for the main and transit signal conductors for the supply and return pipelines)
- markings on terminals (on aluminum tags)
- specification of the devices and materials used.
3. Symbols of SODC elements
The design of UEC systems must be carried out with the possibility of connecting the designed system to existing UEC systems and those planned in the future.
When designing systems, it is necessary to provide for monitoring the insulation condition of an extensive pipeline network based on the maximum range of the detector (five kilometers of pipeline).
The main signal wire is a wire marked on the right in the direction of water supply to the consumer on both pipelines (conventionally tinned). The second signal conductor is called transit.
All side branches must be included in the break of the main signal conductor. It is prohibited to connect side branches to copper wire located on the left along the water supply to the consumer (transit).
The insulation condition must be monitored by a stationary detector. If it is not possible to connect a stationary detector, monitoring can be carried out using a portable detector. At control points at the ends of the heating network, end terminals, one of which may have an output to a stationary detector.
An example is a diagram of the ODS for a section of a heating main less than 100 m long with any of the detectors (see diagrams).
For pipelines less than 100 meters long, it is allowed to install only one control point with a loop of signal conductors under a metal insulation plug at the other end of the pipeline. Some operating organizations in Moscow require the establishment of control points on both sides of the heating main.
Control points must be provided every 250 - 300 meters. Intermediate terminals are installed at the indicated points. At the beginning of side branches 30 - 40 meters long, an intermediate terminal is installed, regardless of the location of other control points on the main pipeline.
At the boundaries of adjacent projects, at the junctions of the routes, it is necessary to provide control points and install double end terminals that allow you to combine or separate the SDS of these projects.
Example of a heating network with double end terminals, branches and control from both sides
In places where polyurethane foam insulation is broken (passage of pipelines through thermal chambers, basements of buildings, etc.), the connection of signal conductors is carried out by cable jumpers through walk-through terminals or by organizing a control point with a walk-through terminal in the ground carpet.
Installing terminals with connectors for switching in rooms with high humidity (thermal chambers, basements, etc.) is not recommended. In such cases, walk-through terminals are installed.
Examples of a heating network:
Scheme of SODC with a thermal chamber with a ground carpet
SODC diagram with walk-through terminals in the basement of the house (chamber)
Maximum length The cable length from the pipeline to the terminal should not exceed 10 meters. If it is necessary to use a longer cable, it is necessary to install an additional terminal as close as possible to the pipeline.
Installation of terminals at intermediate and end control points is carried out in ground or wall carpets of the established type. At the end points of the pipeline, it is allowed to install terminals in the central heating substation. The design of the carpet must prevent the formation of condensation on the elements of the terminal, the penetration of moisture into the terminal and ensure ventilation of the internal volume of the carpet. The internal volume of the carpet should be filled with dry sand from the base to a level of 20 centimeters to the top edge. When installing carpets on heating mains laid in bulk soils, it is necessary to take additional measures to protect the carpet from subsidence.
The connecting cable from the pipeline element with a sealed cable outlet to the terminal must be laid in a galvanized pipe diameter 50 mm. Welding (soldering) of a protective galvanized pipe with a cable laid in it is prohibited.
The laying of the connecting cable inside the tasks (structures) to the installation site of the terminals or at the place where the thermal insulation is broken (in a thermal chamber, etc.) must also be carried out in a galvanized pipe of 50 mm, secured to the wall with brackets. The use of protective corrugated hoses inside buildings is allowed.
The design of the UEC system must be stamped with the surname and initials of the developer and the name of the organization that developed the project. The design of the UEC system must be agreed upon with the organization that accepts the heating main for balance.
If it is necessary to make changes to the UEC scheme, these changes must be re-agreed with the operating organization.
4. Rules for installing the UEC system
- Installation of the ODS must be carried out in accordance with the design diagram agreed upon with the operating organization.
- When insulating joints, signal conductors of adjacent pipeline elements must be connected using crimp couplings, followed by soldering of the junction of the conductors. Soldering must be done using inactive fluxes.
- All side branches from main pipeline must be included in the break of the main signal conductor of the main pipeline. The transit signal conductor must only pass through the main pipeline.
- When insulating joints located at the boundaries of pipelines of various manufacturing companies or various construction organizations, work must be carried out in the presence of representatives of these organizations with the drawing up of an act for the work performed, signed by representatives of all organizations.
- At control points, connecting cables must be connected to signal conductors through sealed cable terminals.
- The design of the cable outlets must ensure tightness throughout the entire service life.
- At control points and transits in cells and basements of houses, NYM 3×1.5 and NYM 5×1.5 cables are used as connecting cables color coded lived In conditions low temperatures it is necessary to use cable brand KGHL 3×1.5 or KGHL 5×1.5.
- The connection of cable cores at intermediate control points with signal conductors in a pre-insulated pipe must be made in accordance with the following color markings:
Blue is the main signal conductor going from this control point towards the consumer.
Brown is a transit signal conductor running from this control point towards the consumer.
Black is the main signal conductor, going from this control point in the direction opposite to the coolant supply.
Black and white - transit signal conductor, going from this control point in the direction opposite to the coolant supply.
Yellow-green - contact to the steel pipeline (“grounding”).
- Contact of the yellow-green core with the steel pipeline must be ensured using a detachable threaded connection(a nut with a washer on a bolt welded to a steel pipeline).
- Pipeline connecting cables must be marked to identify the associated pipes and cables.
- The connection of connecting cables to the terminals at control points must be carried out in accordance with the color markings and the corresponding instructions necessarily attached to each terminal.
- Installation terminals installed at control points must have a protection class of at least IP 54. Terminals installed in places with high humidity (thermal chambers, basements of houses with the risk of flooding) must have a protection class of at least IP 65.
- Aluminum tags with markings indicating the direction of measurement must be attached to the terminals.
- If it is necessary to install cables longer than 10 meters at control points, an additional terminal must be installed.
- Installation of stationary fault detectors must be carried out in accordance with the operating instructions.
- Upon completion of installation of the UEC system, an inspection should be carried out, including:
- measuring the insulation resistance of each signal conductor;
- measuring the resistance of the circuit (loop) of signal conductors;
- measuring the length of signal conductors and the lengths of connecting cables at all control points;
- measurement of reflectograms of signal conductors.
All results of changes are entered into the SODK inspection report. The certificate of delivery of the SODC can be seen below..pdf"].
5. Rules for acceptance of UEC systems into operation
- Acceptance of UEC systems should be carried out jointly by representatives of the construction organization and the organization that installed and commissioned the UEC system, together with representatives of the operating organization.
- When accepting the UEC system into operation, the operating organization must be provided with the following documentation and equipment:
Scheme of remote monitoring of the condition of the pipeline with a completed table of pipeline lengths by section (supply and return pipelines according to the design pipeline diagram and according to the joint diagram);
Joint diagram;
Situational plan;
Monitoring devices (damage detectors, locators, etc.) with components (if any) and with technical documentation for their operation - according to the project.
- In the presence of representatives of the operating organization, the construction organization and the organization that installed and commissioned the UEC system, the following is carried out:
Measurement of ohmic resistance of signal conductors;
Measurement of insulation resistance between signal conductors and ground;
Recording reflectograms of a heating network section using a pulsed reflectometer for use as a reference during operation;
Checking the correct settings of control devices (locators, detectors) transferred into operation for this order.
- All measurement data and initial information are entered into the inspection report of the system for operational remote monitoring of the heating main.
- The UEC system is considered operational if the insulation resistance between the signal conductors and the steel pipeline is not lower than 1 MOhm per 300 m of the heating main. For pipelines with a length different from the specified one, the permissible value of the insulation resistance varies inversely proportional to the length of the pipeline.
Project system for operational remote control of SODK.
In this project, a system was designed for systematic monitoring of the insulation condition and prompt identification of areas with high insulation moisture in pipelines made of polyurethane foam pipes.
Operating principle of SODK pulse type based on measurement electrical resistance thermal insulation layer between the steel pipe and the two copper wires of the control system, forming a signal circuit that runs along the entire length of the pipeline.
Basic requirements for the elements of the SDS system:
1. Distance from copper wire to steel pipe- 15 mm.
2. Insulation resistance monitoring:
The resistance between the signal wire and the steel pipe (for one pipe or fitting - 20 m of wires or less) must be at least 10 MOhm;
The insulation resistance of 300 m of pipeline varies inversely;
To monitor the insulation resistance, a voltage of 500 V should be used.
3. Signal loop resistance control:
Specific resistance of copper wires is 0.012-0.015 Ohm/m;
Excess permissible value The resistance of the signal circuit for the corresponding length of the control system wires indicates a poor-quality connection of the wires at the joints.
In the production of pre-insulated pipes and fittings, copper wires of the control system are installed in them as standard. Tinned copper wire is used as the main “signal” white, which is located in the pipeline on the right in the direction of water movement (for the return pipeline the direction is the same as for the supply). The second wire - bare copper - "transit" runs throughout the heating network without breaks.
For systematic monitoring of the insulation condition, it is possible to use a portable damage detector "Vector 2000" and the ability to connect it to the measuring terminal "KT-11", as well as a locator - a pulse reflectometer "Reis-105R" to determine the exact location of the damage and the type of defect (wet insulation, break of the signal wire) when connecting it to the terminals "KT-11", "KT-12" and "KT-13".
Organization of control using the SODK system:
Control electrical parameters The signal circuit is carried out separately through the supply and return pipelines.
Looping of wires is provided in the end element of the UEC system.
On pipelines with polyurethane foam insulation, two-stage monitoring of moisture and insulation condition must be carried out:
At the first level, constant monitoring of pipelines is required to determine the condition of the insulation - this is carried out by operating personnel using a damage detector, which allows you to determine the presence of damage; to determine the location of the detected damage, a second level of control is needed;
At the second level of control, control should be carried out using a pulse reflectometer (damage locator) and only by highly qualified, specially trained personnel.
To organize such monitoring of the condition of polyurethane foam insulation, it is necessary:
1. Organize periodic monitoring using a portable damage detector: 2-4 times a month.
2. Organize a complete in-depth periodic examination using a pulse reflectometer: once a quarter. The survey data is entered into the database in order to monitor the dynamics of the state of the PU insulation.
3. Organize immediate determination of the location of the damage after the detector is triggered and its elimination.
Installation of the SODK system:
The project was carried out in accordance with the "Instructions for the design, installation and operation of a pulse-type operational remote control system (ORC").
Installation of pipeline joints and installation of the UEC system is carried out by the supplier of PI pipes - ZAO Zavod polymer pipes" Mogilev.
The control system wires are connected at the joints of the elements and are led out through sealed cable terminals into the switching terminals.
Connecting cables from cable terminals to the carpet (three-core NYM3x1.5 and five-core NYM 5x1.5) are laid in protective galvanized steel pipes
d = 50 mm. Welding (soldering) of a pipe with a cable laid in it is prohibited.
The cable connection is carried out in strict accordance with the color marking of the cores, as well as in accordance with the passport attached to each terminal. The cable from the supply pipeline must be additionally marked (with insulating tape) both at the base of the cable outlet and at the entrance to the terminal.
Installation of carpets, placement of terminals and connection of connecting cables is carried out in accordance with the diagrams given in the project.
In this project, the length of the heating network route is 229.5 running meters.
To switch signal conductors and connect control devices, the following types of terminals are used:
End terminal "KT-11" - designed for switching system conductors UEC pipelines with PPU insulation at control points; connecting a pulse reflectometer to the UEC system. The terminal is installed in a wall box of the carpet near the entrance of the heating main to the educational building No. 3 of BelSUT;
Intermediate terminal "KT-12" - designed for switching conductors of the UEC pipeline system with polyurethane foam insulation at intermediate points; connection to the SODK pulse reflectometer. The terminal is installed in an existing ground carpet box in the courtyard of educational buildings No. 3 and No. 4;
End terminal "KT-13" - designed for looping conductors of the UEC system of pipelines with polyurethane foam insulation at the end points of the UEC system; connecting a pulse reflectometer (locator) to the UEC system. The terminal is installed in a carpet wall box in the basement of educational building No. 1.
Purpose
The operational remote monitoring system (ORMS) is designed to carry out continuous monitoring of the condition of the thermal insulation layer of polyurethane foam (PUF) of pre-insulated pipelines throughout their entire service life. SODK is one of the main tools Maintenance pipelines built using “pipe-in-pipe” technology using signal copper conductors. The SODK complex of instruments and equipment makes it possible to locate damage locations in a timely manner and with great accuracy. The use of SODK contributes to the safe operation of pipeline systems and can significantly reduce costs and time for repair work.
Operating principle and system organization
The control system is based on the use of an insulation moisture sensor distributed along the entire length of the pipeline. Signal copper conductors (at least two), located in the heat-insulating layer of each pipeline element, are connected along the entire length of the branched pipeline network into a two-wire line, combined at the end elements into a single loop. Conductors of any branches are included in the break of the signal conductor of the main pipeline. This loop of copper signal conductors, the steel pipe of all pipeline elements and the thermal insulation layer of rigid polyurethane foam between them form the insulation moisture sensor. The electrical and wave properties of this sensor allow:
1. Monitor the length of the humidification sensor or the length of the signal loop and, as a consequence, the length of the pipeline section covered by this sensor.
2. Monitor the humidity state of the heat-insulating layer of the pipeline section covered by this sensor.
3. Search for places where the heat-insulating layer is moistened or where the signal wire is broken in the section of the pipeline covered by this sensor.
Monitoring the length of the humidification sensor is necessary to obtain reliable information about the state of humidity of the heat-insulating layer along the entire length of the pipeline section covered by this sensor. The length of the signal loop (the length of the humidification sensor) is determined as the ratio of the total resistance of the signal conductors connected in a closed circuit to their resistivity. The length of the pipeline section covered by this sensor is half.
When monitoring the humidity state, the principle of measuring the electrical conductivity of the heat-insulating layer is used. With increasing humidity, the electrical conductivity of thermal insulation increases and the insulation resistance decreases. An increase in the humidity of the thermal insulation layer can be caused by leakage of coolant from a steel pipeline or penetration of moisture through the outer shell of the pipeline.
The search for damage sites is carried out on the principle of pulse reflection (pulse reflectometry method). Moistening of the insulating layer or a wire break leads to a change in the wave characteristics of the insulation moistening sensor in specific local areas. The essence of the reflected pulse method is to probe a line of signal conductors with high-frequency pulses. Determining the delay between the time of sending probing pulses and the time of receiving pulses reflected from inhomogeneities of wave impedances (wet insulation or damage to signal conductors) allows you to calculate the distances to these inhomogeneities.
For operational work with the insulation moisture sensor, the signal conductors and the “mass” of the steel pipe body are removed from the heat-insulating layer. These outputs are organized using special pipeline elements in which the signal conductors are output by a cable passing through the external insulation using a sealing device. These cables, led out into technological rooms, ground or wall carpets, together with the terminals connected to them, form control and switching points along the route - technological measuring points.
There are different end and intermediate measuring technological points.
Pipeline end elements with cable outlets are used at end measuring points. Cables from the supply and return pipes are connected to the end terminal installed in technological rooms or structures, ground or wall carpets.
At intermediate points, pipeline elements with an intermediate cable outlet are usually used. Cables from both pipelines are brought out into the ground carpet or technological structures and connected to an intermediate or double end terminal. But in places where the thermal insulation is broken (in a thermal chamber, etc.), the organization of an intermediate measuring point is carried out using end elements with cable leads. Cables from all pipeline elements are led out into the ground carpet or technological structure and connected to the appropriate terminal.
Technological measuring points installed at certain distances make it possible to quickly carry out exploratory measurements with sufficient accuracy.
Part of the equipment
The control system is divided into the following parts: pipe, signal and additional devices.
The pipe part is all the pipeline elements and components that directly form the insulation moisture sensor:
- Pipe components with two or more copper signal conductors.
- Intermediate and end cable terminals.
- Pipeline end elements.
- Installation and connection kits for connecting signal conductors when waterproofing joints and for extending cable outlets.
Pipeline elements with two or more copper signal conductors are pre-insulated pipes, bends, expansion joints, tees, Ball Valves, and so on.
Signal conductors installed inside the polyurethane foam insulation of each element are located parallel to the steel heat-carrying pipe at a distance of 16÷25 mm. from her. When assembling pipes, the conductors are fixed in polyethylene sheath centralizers, which are installed at a distance of 0.8÷1.2 m from each other. These conductors are made from copper wire cross section 1.5 mm 2 (grade MM 1.5).
In all elements, the control system wires are located in the “ten minutes to two o’clock” position.
The end cable outlet is installed at the end of the thermal insulation. Structurally, it can be performed in two versions.
The first option is a pipeline end element with a cable outlet and a metal insulation plug (ZIM KV). In this element, two wires of a three-core cable are connected to the signal conductors at the end of the pipe, the third wire is connected to the steel pipe, and the cable is exited through a sealing device installed on the insulation plug. This option is used to route signal conductors inside engineering structures and technological premises.
The second option is a pipeline end element with a metal insulation plug and a cable outlet (KV ZIM). In this element, two wires of a three-core cable are connected to the break of the main signal wire, the third wire is connected to the steel pipe, and the cable is brought out through a sealing device installed on the pipe shell. This option is used to route signal conductors into special technological devices (carpets) installed outside engineering structures and buildings.
Intermediate cable outlets are designed to divide an extensive pipeline network into sections of a certain length, which provides the necessary accuracy when troubleshooting the control system. They are installed along the length of the route through distances determined regulatory documentation(SP 41-105-2002) and agreed with operating organizations. The intermediate cable outlet is made in the form special element a pipeline in which four wires of a five-core cable are connected to the break of the signal wires, the fifth wire is connected to the working pipe, and the cable itself is discharged through a sealing device installed on the pipe shell.
The end elements of the pipeline are installed at the end of the thermal insulation and are designed to combine a two-wire line into a single loop and protect the thermal insulation layer from moisture penetration. The connection of the signal conductors to each other at the end elements of the pipeline is made at the end of the insulating layer under the insulation plug.
The insulation resistance of each signal conductor of any element is at least 10 MΩ.
Installation and connection kits
The SODK wire connection kit (included in the kits of materials for sealing butt joints) is designed to connect the SODK wires and fix them on the heat-carrying pipe at a certain distance from it.
Delivery set for 1 joint:
- wire holder - 2 pcs.
- crimp coupling for connecting wires - 2 pcs.
- solder, quantity per 1 joint - 2g
- flux or solder paste - 1g
- tape with adhesive layer - according to the table:
| Outer diameter of steel pipe | Consumption of tape with adhesive layer per 1 joint |
| d, mm | m |
| 57 | 0,5 |
| 76 | 0,7 |
| 89 | 0,85 |
| 108 | 1,02 |
| 133 | 1,26 |
| 159 | 1,5 |
| 219 | 2,1 |
| 273 | 2,6 |
| 325 | 3,1 |
| 377 | 3,55 |
| 426 | 4,05 |
| 530 | 5,02 |
The three-core output cable extension kit is used to extend the three-core cable of the UEC system at the cable terminals during pipeline installation.
Contents of delivery:
Three-core cable - 5 m;
Heat shrink tube with a diameter of 25 mm L= 0.12 m;
Tape mastic "Gerlen" - 0.2 m2;
Electrical tape - 1 roll for 10 sets;
Crimp coupling for connecting wires - 3 pcs;
Heat-shrink tube with a diameter of 6 mm L= 3cm - 3 pcs;
Consumables (not included in delivery):
Solder - 3g.
- flux or solder paste - 1.5 g.
Five-core cable extension kit output used to extend the five-core cable of the UEC system at the intermediate cable outlet during pipeline installation.
Contents of delivery:
Five-core cable - 5 m;
Heat shrink tube with diameters of 25 mm - 0.12 m;
Tape mastic "Guerlain" - 0.2 m2;
Electrical tape - 1 roll 1 - 8 sets;
Crimp sleeve for splicing wires - 5 pcs.
Heat shrink tube with a diameter of 6 mm L= 3cm - 5 pcs.
Consumables (not included in delivery):
Solder - 5g.
- flux or solder paste - 2.5 g.
Signal part consists of interface elements and devices:
- Measuring and switching terminals for connecting devices at control and switching points of signal conductors.
- Monitoring devices (detectors, indicators) portable and stationary.
- Fault locating devices (pulse reflectometer).
- Measuring instruments (insulation tester, megger, ohmmeter).
- Cables for installation connection of terminals and connection of terminals with stationary control devices.
To switch signal conductors and connect devices to connecting cables at control and switching points, special switching boxes - terminals are used.
Terminals are divided into two main types: measuring and sealed.
Measuring The terminals are designed for prompt switching of signal conductors during measurements. The necessary switching and measurements are made using external plug connectors, without opening the terminal. Terminals of this type are installed in dry or well-ventilated engineering devices(ground or wall carpets, etc.) and technological rooms (central heating center, electrical transformer room, etc.).
Sealed terminals are designed for switching signal conductors in conditions high humidity. The necessary switching and measurements are made using connectors installed inside the terminals. Access to them requires removal of the terminal cover. Terminals of this type can be installed in any technological devices(ground or wall carpets, etc.), structures and premises (in thermal chambers, in the basements of houses, etc.)
Types of measuring terminals:
End terminal (KT-11, KIT, KSP 10-2 and TKI, TKIM) - installed at control points at the ends of the pipeline;
End terminal with output to a stationary detector (KT-15, KT-14, IT-15, IT-14, KDT, KDT2, KSP 12-5 and TKD) - installed at the end of the pipeline, at the control point where a connection to a stationary detector is provided ;
Intermediate terminal (KT-12/Sh, IT-12/Sh, PIT, KSP 10-3, TPI and TPIM) - installed at intermediate pipeline control points and at control points at the beginning of side branches.
Double end terminal (KT-12/Sh, IT-12/Sh, DKIT, KSP 10-4 and TDKI) - installed at the control point on the separation boundary of control systems of associated projects;
Types of sealed terminals:
The end terminal is sealed - installed at control points at the ends of the pipeline;
Intermediate terminal (KT-12, IT-12, PGT and TPG) - installed at intermediate pipeline control points and at control points at the beginning of side branches.
Sealed connecting terminal (KT-16, IT-16, OT6, OT4, OT3, KSP 13-3, KSP 12-3, TO-3 and TO-4) - installed at those control points where it is necessary to combine several pipeline sections or several separate pipelines;
A sealed connecting terminal with access to a stationary detector (KT-16, IT-16, OT6, OT3, KSP 13-3, KSP 12-3 and TO-3) - installed at the control point where it is necessary to combine several separate pipelines into a single loop , and which provides for connecting a cable from a stationary detector;
Sealed pass-through terminal (KT-15, IT-15, PT, KSP 12 and TP) - installed in places where polyurethane foam insulation breaks (in thermal chambers, in the basements of houses, etc.) for switching connecting cables or installing an additional control point when the need to use long connecting cables.
Compliance of terminals produced by NPK VECTOR, LLC TERMOLINE, NPO STROPOLYMER, JSC MOSFLOWLINE and terminals of the TermoVita series
| OOO "TERMOLINE" | NPK "VECTOR" | NGO "STROYPOLYMER" | JSC "MOSFLOWLINE" | |
| KT-11 | IT-11 | WHALE | KSP 10-2 | End terminal. |
| KT-12 | IT-12 | PGT | No | ---- |
| KT-12/Sh | IT-12/Sh | PETE, DKIT | KSP 10-3, KSP 10-4 | Intermediate terminal, double end terminal |
| KT-13 | IT-13 | KGT | KSP 10 | ---- |
| KT-15 | IT-15 | KDT | KSP 12-5 | Terminal with output to detector |
| KT-14 | IT-14 |
KDT2 | KSP 12-5 (2 pieces) | Terminal with output to detector (2 pieces) |
| KT-15 | IT-15 | PT, OT4 | KSP 12 | Passage terminal |
| KT-15/Sh | IT-15/Sh | KIT4 | KSP 12-2, KSP 12-4 | ---- |
| KT-16 | IT-16 | OT6, OT3 (2 pieces) | KSP 13-3, KSP 12-3 (2 pieces) | __ |
The terminals are connected to the UEC conductors using connecting cables: a 3-core cable (NYM 3x1.5) for connecting terminals at the end sections of the heating main and a 5-core cable (NYM 5x1.5) for connecting terminals at intermediate sections of the heating main. Connection and operation of the terminals is carried out in accordance with the technical documentation of the manufacturer.
Control devices
Monitoring the condition of the UEC system during pipeline operation is carried out using a device called detector. This device records the electrical conductivity of the heat-insulating layer. When water gets into the thermal insulation layer, its conductivity increases and this is recorded by the detector. At the same time, the detector measures the resistance of conductors connected in a closed circuit.
Detectors can be powered from a 220 Volt network (stationary), or from an autonomous 9 Volt power source (portable).
Stationary detector allows you to simultaneously monitor two pipes with a maximum length of 2.5 to 5 km each, depending on the model.
Table 1
Technical characteristics of stationary detectors
| Options | Vector-2000 | PIKKON | SD-M2 | |||
| DPS-2A | DPS-2AM | DPS-4A | DPS-4AM | |||
| Supply voltage, V | 220 (+10-15)% | 220 (+10-15)% | 220 (+10-15)% | |||
| Number of controlled pipeline sections, pcs. | from 1 to 4 | 2 | 4 | 2 | ||
| up to 2500 | up to 2500 | 5000 | ||||
| more than 600 | more than 200 | more than 150 | ||||
| Insulation wetness indication, kOhm | less than 5 (+10%) | less than 5 (+10%) | Multi-level more than 100 from 30 to 100 from 10 to 30 from 3 to 10 less than 3 | |||
| 10 DC | 8 Direct current | 4 Alternating current | ||||
| 30 | 30 | 120 (2 tu.) | ||||
| Operating temperature environment, WITH | -45 - +50 | -45 - +50 | -45 - +50 | -40 - +55 | ||
| no more than 98 (25 °C) | 45÷75 | 45÷75 | No data | |||
| Protection class from external influences | IP 55 | IP 55 | IP 67 | |||
| Overall dimensions, mm | 145x220x75 | 170x155x65 | 220x175x65 | 180x180x60 | ||
| Weight, kg | no more than 1 | no more than 0.7 | no more than 1 | 0,75 | ||
When using a stationary detector SD-M2, it is possible to organize a centralized SODC of a branched heating network of considerable length (up to 5 km) from a single control center. For this purpose, the stationary detector has galvanically isolated contacts for each channel, which close when a malfunction occurs.
Connection and operation of stationary detectors is carried out in accordance with the technical documentation of the manufacturer.
The portable detector allows you to monitor a pipe with a maximum length of 2 to 5 km, depending on the model. One detector can control different areas pipelines that are not interconnected in unified system. The portable detector is not permanently installed at the site, but is connected to the controlled area by the employee conducting the inspection as part of its operation.
table 2
Technical characteristics of portable detectors
| Options | Vector-2000 | PIKKON DPP-A | PIKKON DPP-AM | DA-M2 |
| Supply voltage, V | 9 | 9 | 9 | |
| Length of one controlled section of the pipeline, m | up to 2000 | up to 2000 |
5000 | |
| Indication of signal wire damage, Ohm | more than 600(+10%) | more than 200(+10%) | 150 | |
| Test voltage on signal wires, V | 10 DC | 8 Direct current | 4 Alternating current | |
| Indication of wetness of PPU insulation, kOhm | less than 5 (+10%) | less than 5 (+10%) | Multi-level more than 1000 from 500 to 1000 from 100 to 500 from 50 to 100 from 5 to 50 | Multi-level more than 100 from 30 to 100 from 10 to 30 from 3 to 10 less than 3 |
| Current consumption in operating mode, mA | 1,5 | 1,5 | No more than 20 | |
| Operating ambient temperature, "WITH | -45 - +50 | -45 - +50 | -20 - +40 | |
| Operating ambient humidity, % | no more than 98 (25 °C) | 45÷75 | Splashproof | |
| Overall dimensions, mm | 70x135x24 | 70x135x24 | 135x70x25 | |
| Weight, g | no more than 100 | no more than 170 | 150 | |
Connection and operation of portable detectors is carried out in accordance with the technical documentation of the manufacturer.
Damage detection devices
Used to determine the location of damage pulse reflectometer, providing acceptable measurement accuracy. The reflectometer allows you to determine damage at distances from 2 to 10 km, depending on the model used. The measurement error is approximately 1-2% of the length of the measured line. The accuracy of measurements is determined not by the error of reflectometers, but by the error of the wave characteristics of all pipeline elements (wave impedance of the insulation moisture sensor). Depending on the amount of insulation moisture, the reflectometer allows you to determine the location of several places with reduced insulation resistance.
Technical characteristics of domestic pulse reflectometers
| Name | FLIGHT-105 | FLIGHT-205 | RI-10M | RI-20M |
| Manufacturing plant | NPP "STELL", Bryansk | JSC "ERSTED", St. Petersburg | ||
| Measuring distance range | 12.5 -25600 m |
12.5-102400m | 1- 20000 m | 1m-50km. |
| Resolution | Not worse than 0.02 m | 0.2% on ranges from 100 to 102400 m | 1% of range | 25 cm... 250 m (range) |
| Measurement error | Less than 1% | Less than 1% | Less than 1% | Less than 1% |
| Output impedance | 20 - 470 Ohm, continuously adjustable | from 30 to 410, continuously adjustable | 20 - 200 Ohm. | thirty. . 1000 Ohm. |
| Sounding signals | Pulse amplitude 5 V, 7 ns - 10 μs; | Pulse amplitude 7 V and 22 V from 10 to 30-10 3 ns | Pulse amplitude 6 V, 10 ns - 20 μs; | Pulse amplitude of at least 10 V. 10 ns. .50 µs. |
| Stretching | Possibility of stretching the reflectogram around the measuring or zero cursor by 2,4,8, 16, ...131072 times | 0.1 of range | 0.025 of range | |
| Memory | 200 reflectograms; | up to 500 reflectograms | 100 reflectograms | 16 MB. |
| Interface | RS-232 | RS-232 | RS-232 | RS-232 |
| Gain | 60 dB | 86 dB | -20... +40 dB. | -20... +40 dB. |
| KU installation range (v/2) | 1.000...7.000 | 1.000...7.000 | 1.00...3.00 (50 m/µs... 150 m/µs). | |
| Display | LCD 320x240 pixels with backlight | LCD 128x64 pixels with backlight | LCD 240x128 pixels with backlight | |
| Nutrition |
built-in battery - 4.2÷6V network - 220÷240 V, 47-400 Hz DC network - 11÷15V | built-in battery - 10.2-14 DC network - 11÷15V network - 220÷240 | built-in battery - 12 V; network - 220V 50Hz, via adapter Time continuous operation battery life for at least 6 hours (with backlight). | built-in battery - 12 V; mains - 220V 50Hz, via adapter. Continuous battery life is at least 5 hours (with backlight). |
| Power consumption | No more than 2.5 W | 5 W | 3 VA | 4VA |
| Operating temperature range | - 10 °C + 50 °C | - 10 °C + 50 °C | -20С...+40С | -20С...+40С |
| dimensions | 106x224x40 mm | 275x166x70 | 267x157x62 | 220x200x110 mm |
| Weight | No more than 0.7 kg (with built-in batteries) | No more than 2 kg (with built-in batteries) | no more than 2.5 kg (with built-in batteries) | |
FLIGHT-205
Reflectometer REIS-205 along with the traditional pulse reflectometry method, in which the length of the line, the distance to places short circuit, breakage, low-resistance leakage and longitudinal increase in resistance (for example, in places where cores are twisted, etc.), additionally implements m skeleton measurement method.What allows you to accurately measure loop resistance, ohmic asymmetry, line capacitance, insulation resistance, and determine the distance to the location of high-resistance damage (lower insulation) or line break.
Connection and operation of pulse reflectometers is carried out in accordance with the technical documentation of the manufacturer.
Additional devices
Ground and wall carpets
Purpose
The carpet, both ground-mounted and wall-mounted, is designed to accommodate switching terminals and protects elements of the control system from unauthorized access.
The carpet is metal structure with a reliable locking device. There is a place inside the carpet for attaching the terminal.
Design
The design of systems must be carried out with the possibility of connecting the designed system to control systems for existing pipelines and pipelines planned in the future. The maximum length of an extensive pipeline network for the designed control system is selected based on the maximum range of control devices (five kilometers of pipeline).
The choice of the type of control devices for the designed section should be made based on the possibility of supplying (availability) of 220 V voltage to the designed section for the entire period of operation of the pipeline. In the presence of voltage, it is necessary to use a stationary fault detector, and in the absence of voltage, a portable detector with an autonomous power supply.
The choice of the number of devices for the designed section should be made taking into account the length of the designed pipeline section.
If the length of the designed section is greater than the maximum length controlled by one detector (see characteristics in the passport), then it is necessary to divide the heating main into several sections with independent systems control.
The number of plots is determined by the formula:
N= Lnp/Lmax,
where /_pr is the length of the designed heating main, m;
L^ ax -maximum range of the detector, m.
Round the resulting value up to a whole number.
Note. One portable detector can monitor several independent sections of heating networks.
Test points are designed to allow operating personnel access to signal wires to determine the condition of the pipeline.
Control points are divided into end and intermediate. End control points are located at all end points of the designed pipeline. When the length of the section is less than 100 meters, it is allowed to install only one control point, with a loop of signal conductors under a metal plug at the other end of the pipeline.
Control points are located so that the distance between two adjacent control points does not exceed 300 m. At the beginning of each side branch from the main pipeline, if its length is 30 m or more (regardless of the location of other control points on the main pipeline), an intermediate terminal is placed .
At the boundaries of adjacent heating network projects, at the points of their connection, it is necessary to provide control points and install double end terminals that allow the UEC system of these sections to be combined or separated.
When connecting conductors of the UEC system in series at the end of the insulation (passage of pipelines through thermal chambers, basements of buildings, etc.), the connection of conductors must be made only through terminals.
The maximum cable length from the pipeline to the terminal should not exceed 10 m. If it is necessary to use a longer cable, it is necessary to install an additional terminal as close as possible to the pipeline.
Each control point must include:
- pipeline element with output cable;
- connection cable;
- switching terminal.
It is not recommended to place control points in thermal chambers due to humidity in the chamber, however, it is allowed only in cases where the placement of the ground carpet is associated with any difficulties (damage to appearance cities, impact on traffic safety, etc.). In these cases, the terminals placed in thermal chambers must be sealed. In the basements of houses, the placement of control points is not recommended if the designed heating main and the house belong to different departments, since in these cases a conflict is possible during the operation of pipelines (due to problems with access to control points and the safety of elements of the UEC system). In these cases, it is recommended to equip the control point with a ground carpet installed 2 - 3 meters from the house.
Installation of terminals at intermediate and end control points is carried out in ground or wall carpets of the established type. At the end points of the pipeline, it is allowed to install terminals in the central heating substation.
Control system design rules
(in accordance with SP 41-105-2002)
- As the main signal wire, a marked wire is used, located on the right in the direction of water supply to the consumer on both pipelines (conventionally tinned). The second signal conductor is called transit.
- Conductors of any branches must be included in the break of the main signal conductor of the main pipeline. It is prohibited to connect side branches to the copper wire located on the left along the water supply to the consumer.
- When designing interfacing projects, intermediate cable outlets with double end terminals are installed at the junction points of the routes, which make it possible to combine or separate the control systems of these projects.
- At the ends of the routes of a single project, cable terminations with end terminals are installed. One of these terminals may have an output to a stationary detector.
- Along the entire route, at distances not exceeding 300 meters, intermediate cable outlets with intermediate terminals are installed.
- Intermediate cable terminals on heating mains must be additionally installed on all side branches longer than 30 meters, regardless of the location of other terminals on the main pipe.
- The control system must ensure that measurements are taken on both sides of the controlled section when its length is more than 100 meters.
- For pipelines or end sections less than 100 meters in length, it is permissible to install one end or intermediate cable outlet and its corresponding terminal. At the other end of the pipeline, a line of signal conductors is connected into a loop under a metal insulation plug.
- When connecting signal conductors in series, at the end of polyurethane foam insulation (passage through chambers, basements of buildings, etc.), as well as when combining control systems different pipes(supply with return, heating network with hot water supply), connect cables between sections of pipelines only using pass-through, connecting or sealed terminals.
- The specification must indicate the length of the cable for a specific point, taking into account the depth of the heating main, the height of the carpet, the distance of its (carpet) removal to the mainland soil and 0.5 meters of reserve.
- The maximum cable length from the pipeline to the terminal should not exceed 10 meters. In the case when it is necessary to use a cable with a longer length, it is necessary to install an additional pass-through terminal. The terminal is installed as close to the pipeline as possible.
- The installation of stationary detectors on pipelines that enter process rooms with constant access by maintenance personnel is mandatory.
Control system diagram
The control system diagram consists of a graphical representation of the signal conductor connection diagram, repeating the route configuration.
The diagram shows:
F installation locations of cable outlets and control points, indicating the types of terminals, detectors and types of carpets (ground or wall) in graphical form;
F are indicated symbols all elements used in the control system diagram;
F, characteristic points corresponding to the installation diagram are indicated: branches from the main trunk of the heating main (including drains); turning angles; fixed supports; diameter transitions; cable outlets.
The diagram is accompanied by a data table for characteristic points indicating the following parameters:
F point numbers according to design documentation;
F pipe diameter at the site;
F is the length of the pipeline between points according to the design documentation for the supply pipeline;
F is the length of the pipeline between points according to the design documentation for the return pipeline;
F is the length of the pipeline between points according to the joint diagram (separately for the main and transit signal conductors of each pipeline);
F length of connecting cables at all control points (separately for each pipeline).
Additionally, the control scheme must contain:
F diagrams for connecting connecting cables to signal conductors;
F diagrams for connecting cables to terminals and stationary detectors;
F specification of the devices and materials used;
F sketches of markings of external and internal connectors in directions.
The design of the control system must be agreed upon with the organization accepting the heating main for balance.
Installation of the UEC system
Installation of the UEC system is carried out after welding the pipes and carrying out hydraulic test pipeline.
When installing pipeline elements on construction site, before starting welding of the joint, the pipes must be oriented in such a way as to ensure the location of the wires of the UEC system along the side parts of the joint, and the leads of the wires of one pipeline element are located opposite the leads of the other, thereby ensuring the possibility of connecting the wires over the shortest distance. It is not allowed to place signal wires at the bottomquarter joint.
At the same time, the installed pipeline elements are checked for insulation condition (visually and electrically) and the integrity of the signal conductors. And all pipeline elements with cable outlets require additional measurement of the circuit of the yellow-green wire of the outlet cable and the steel pipe. Resistance should be ≈ 0 ohm.
When conducting welding work The ends of the polyurethane foam insulation should be protected with removable aluminum (or tin) screens to prevent damage to the signal wires and the insulating layer.
During the installation work conduct precise measurements the lengths of each pipeline element (along a steel pipe), with the results entered into the as-built diagram of butt joints.
The connection of signal conductors is made strictly according to the design diagram of the control system.
Conductors of any branches must be included in the break of the main signal conductor of the main pipeline. It is prohibited to connect side branches to the copper wire located on the left along the water supply to the consumer.
The main signal wire is a marked wire located on the right in the direction of water supply to the consumer on both pipelines (conventionally tinned).
Signal conductors of adjacent pipeline elements must be connected using crimp couplings with subsequent soldering of the conductor junction. Crimping couplings with inserted wires should only be done special tool (crimping pliers). Crimping is carried out with the middle working part of the tool marked 1.5. It is prohibited to perform crimping of crimp couplings. non-standard tools(nippers, pliers, etc.)
Soldering must be performed using inactive fluxes. Recommended flux LTI-120. Recommended solder POS-61.
When connecting wires at joints, all signal wires are fixed on wire holders (stands), which are attached to the pipe using tape (adhesive tape). The use of chlorine-containing materials is prohibited. It is also prohibited to run insulation over the wires, securing the posts and wires at the same time.
When installing pipeline elements with cable outlets, mark the free end of the signal cable from the supply pipeline with insulating tape.
Minstallation of conductors of the UEC system duringjoint insulation work
1. Before installing signal wires, the steel pipe is cleaned of dust and moisture. The polyurethane foam at the ends of the pipe is cleaned: it must be dry and clean.
3. Straighten the wires.
4. Cut the wires to be connected, having previously measured required length. Clean the wires with sandpaper.
5. Connect the wires at the opposite end of the pipeline element or mounted section and check them for absence of short circuit to the pipe.
6. Connect both wires to the device and measure the resistance: it should not exceed 1.5 Ohms per 100 m of wires.
7. Clean the area of the steel pipe from rust and scale. Connect one cable of the device to the pipe, the second to one of the signal conductors. At a voltage of 250 V, the insulation resistance of any pipeline element must be at least 10 MΩ, and the insulation resistance of a 300 m long pipeline section must not be less than 1 MΩ. As the length of the conductors increases, their resistance will decrease. The actual measured insulation resistance must be no less than the value determined by the formula:
Rfrom = 300/ Lfrom
Rfrom- measured insulation resistance, MOhm
Lfrom- length of the pipeline section being measured, m.
Too little resistance indicates increased moisture in the insulation or contact between the signal wires and the steel pipe.
8. Secure the wires at the junction using stands and adhesive tape. Do not apply adhesive tape over the wires, securing the posts and wires at the same time.
9. Connect the wires according to the instructions “Connection of conductors of the UEC system”.
10. Perform thermal and waterproofing of the joint. The type of thermal and waterproofing is determined by the project.
11. Upon completion of work, check the insulation resistance and resistance of the wire loops of the UEC system of the mounted sections. Record the measurement results in the “Work Log”.
If the signal wire breaks at the exit from the insulation, you need to remove the polyurethane foam insulation around the broken wire in an area sufficient for a reliable connection of the wires. The connection is made using crimp sleeves and soldering. Extension of short wires is done in the same way.
When installing wires signaling system At each junction, the signal circuit and insulation resistance are monitored in accordance with the diagram below:
After waterproofing, check the insulation resistance and resistance of the wire loops of the UEC system of the installed sections, and record the obtained data in the work completion report or measurement report.
Control measurements of system parametersUEC topicson pipeline elements
1. Straighten the wire leads and lay them so that they are parallel to the pipe. Carefully inspect the wires - there should be no cracks, cuts or burrs on them. When taking measurements on cable terminals, remove the outer insulation of the cable at a distance of 40 mm. from its end and insulate each core by 10-15 mm. Clean the ends of the wires using emery cloth until a characteristic copper sheen appears.
2. Short the two wires at one end of the pipe. Make sure that the contact between the wires is reliable and the wires do not touch metal pipe. Perform similar operations to check the wires in the taps. For T-branches, the wires must be closed at both ends of the main pipe, forming a single loop. When ending a pipeline section with a cable outlet element, connect the corresponding cable cores running in the same direction.
3. Connect a device for measuring insulation resistance and monitoring circuit integrity (STANDARD 1800 IN or similar) to the conductors at the open end and measure the resistance of the wires: the resistance should be in the range of 0.012-0.015 Ohms per meter of conductor.
4. Clean the pipe, connect one of the device cables to it, and connect the second cable to one of the wires. At a voltage of 500 V, if the insulation is dry, the device should show infinity. The permissible insulation resistance of each pipe or other pipeline element must be at least 10 MOhm.
5. When measuring the insulation resistance of a pipeline section consisting of several elements, the measuring voltage should not exceed 250 V. The insulation resistance is considered satisfactory at a value of 1 MΩ per 300 meters of pipeline. When measuring the insulation resistance of pipeline sections with different lengths, it should be taken into account that the insulation resistance is inversely proportional to the length of the pipeline.
Installation of control points
Ground carpets are installed on the mainland soil next to the pipeline at the points indicated on the control system diagram. The installation location of the ground carpet at a specific point is determined locally by the construction organization, taking into account ease of maintenance. The internal volume of the ground carpet should be filled with dry sand from the base to a level of 20 centimeters from the top edge.
After installing the carpet, its geodetic reference is carried out. When installing carpets on heating mains laid in bulk soils, additional measures should be taken to protect the carpet from subsidence and damage to the signal cable.
When installing a carpet on heating mains laid in bulk soils, it is necessary to take additional measures to protect the carpet from soil subsidence.
The outer surface of the carpet is protected with an anti-corrosion coating.
The wall carpet is attached to the wall of the building, or with outside, or from the inside. The wall carpet is mounted 1.5 meters from horizontal surface(floor of a building, chamber or ground).
Connecting cables from pipeline elements with a sealed cable outlet to the carpet are laid in pipes (galvanized, polyethylene) or in a protective corrugated hose. Laying the connecting cable inside buildings (structures) to the installation site of the terminals must also be carried out in galvanized pipes or in protective corrugated hoses that are fixed to the walls. It is possible to use PE pipes. Laying the connecting cable at the point where the thermal insulation is broken (in a thermal chamber, etc.) must also be carried out in a galvanized pipe fixed to the wall.
Installation of terminals and detectors should be carried out in accordance with the markings given on the attached diagrams and accompanying documentation for these products.
Upon completion of installation, mark the nameplates (tags) on each terminal according to the sketches for marking the connectors in the directions.
On the inside of the cover of each carpet, weld the project number and the number of the point where the carpet is installed.
At the end of the work, check the insulation resistance and resistance of the wire loops of the UEC system and document the measurement results in an inspection report of the control system parameters. In the same act, the lengths of the signal lines of each section of the pipeline and connecting cables at each measuring point should be recorded, separately for the supply and return pipelines. Measurements should be carried out with the detector turned off.
Acceptance of the UEC system into operation.
Acceptance of the UEC system must be carried out by representatives of the operating organization. In the presence of representatives of technical supervision, the construction organization and the organization that installed and adjusted the UEC system during a comprehensive inspection, the following is carried out:
Measurement of ohmic resistance of signal conductors;
Measurement of insulation resistance between signal conductors and working pipe;
Recording reflectograms of heating network sections using a pulsed reflectometer for use as a reference during operation. It is recommended to create a primary data bank by taking reflectograms of each wire between the nearest measuring points from opposite directions;
Correct settings of control devices (locators, detectors) transferred for operation for a given facility.
All measurement data and initial information (length of pipelines, lengths of connecting cables at each control point, etc.) are entered into the acceptance certificate of the UEC system.
The UEC system is considered operational if the insulation resistance between the signal conductors and the steel pipeline is not lower than 1 MOhm per 300 m of the heating main. To control the insulation resistance, a voltage of 250V should be used. The loop resistance of signal conductors should be in the range of 0.012 - 0.015 Ohms per meter of conductor, including connecting cables.
Rules for operating UEC systems.
To promptly identify faults in UEC systems, it is necessary to ensure regular monitoring of the system condition.
The state of the UEC system must be constantly monitored by a stationary detector. Portable detectors are used only on sections of heating mains where it is not possible to install a stationary detector (lack of a 220 V network) or during production repair work. During repair work, the monitoring system of the repaired area between the nearest measuring points is removed from the general system. General system control is divided into local areas. During repairs, the state of the UEC system of each of these sections, separated from the stationary detector, is monitored using a portable detector.
Monitoring the state of the UEC system includes:
1. Monitoring the integrity of the signal conductor loop.
2. Monitoring the insulation condition of the controlled pipeline.
If a malfunction of the UEC system is detected (breakage or moisture), it is necessary to check the presence and correct connection of terminal connectors at all control points, and then take repeated measurements.
When confirming malfunctions of UEC systems of heating mains that are under warranty from the construction organization (the organization that installs, commissions and commissions the UEC system), the operating organization notifies about the nature of the malfunction construction organization, which searches and determines the cause of the malfunction.
Locating damage locations
The search for damage sites is carried out on the principle of pulse reflection (pulse reflectometry method). The signal wire, the working pipe and the insulation between them form a two-wire line with certain wave properties. Moistening of the insulation or a wire break leads to a change in the wave characteristics of this two-wire line. Work on troubleshooting the control system is carried out instrumentally using a pulse reflectometer and a megger in accordance with the technical documentation for these devices. This work consists of the following stages:
1. A single section of pipeline with a broken signal wire or with reduced insulation resistance is determined using an indicator (detector) or a megger. A single section is defined as the section of the heating network between the nearest measuring points.
2. The wires of the UEC system are decommutated in a designated area.
3. Next, reflectograms of each wire are taken separately from opposite directions. If there are primary reflectograms taken during delivery of the UEC system, they are compared with the newly obtained reflectograms.
4. The obtained data is superimposed on the joint diagram. That is, the distances from the reflectograms are compared with the distances on the joint diagram.
5. Based on the results of data analysis, the pipeline is excavated for repair work. After excavation, it is possible to carry out control openings of the insulation in the area where the signal wires pass to obtain clarifying information.
Types of faults recorded by the monitoring system on pipelines with polyurethane foamisolation.
A. Signal wire break
According to the parameters of the UEC system, it is characterized by the absence or increased value of loop resistance.
1. Mechanical damage to the external insulation of pipelines and connecting cables.
2. Fatigue breakage of signal wires during thermal cycles in places of mechanical stress (cuts, breaks, pulling, etc.)
3. Oxidation of the connection points of signal wires inside the external insulation of pipelines and in the places where connecting cables are connected or extended (lack of soldering, overheating of the soldered joint, use of active fluxes without flushing the connection.)
4. Switching breaks on terminals (defects in solder connections, oxidation, deformation and fatigue of spring contacts of switching connectors, loosening of screw clamps of connecting blocks).
B. Wetting of polyurethane foam insulation.
According to the parameters of the UEC system, it is characterized by a reduced insulation resistance.
1. Leakage of external insulation.
A. Mechanical damage to external insulation and connecting cables (breaks and breakdowns).
b. Defects in the welds of the polyethylene shell of fittings (failure to penetrate, cracks).
V. Leakage of joint insulation (lack of penetration, lack of adhesion of adhesive materials).
2. Internal wetting.
A. Defects in welds of steel pipes.
b. Fistulas from internal corrosion.
B. Signal wire shorted to pipe.
According to the parameters of the UEC system, it is characterized by a very low insulation resistance.
Causes:
Destruction of the film of polyurethane foam components between the pipe and the signal wire during thermal cycles. A manufacturing defect is the proximity of the wire to the pipe. Detection is not difficult and is done in the same way as searching for wet spots.
The UEC system allows you to monitor the condition of the pipeline, promptly signal a malfunction, and accurately indicate the location of any defect. The presence of the UEC system significantly saves cash and reduces the time spent on pipeline maintenance.
The monitoring system allows you to detect the following defects:
- Damage to a metal pipe (fistula).
- Damage to the polyethylene shell.
- Breakage of signal conductors.
- Shorting signal conductors to a metal pipe.
- Poor connection of signal wires at the joints.
Composition of the UEC system
The operational remote control system is a special set of instruments and auxiliary equipment(which will be further referred to as elements of the UEC system) with the help of which the condition of the pipeline is monitored. The exclusion of any element from the system violates its integrity and regulatory functionality.
The control system includes the following components:
- Signal conductors
- Control and measuring equipment (damage detectors, pulse reflectometer - locator, control and installation device "Robin KMR 3050 DL").
- Switching terminals.
- Connecting cables.
- Ground and wall carpets.
- Materials and equipment for installation.
Signal conductors
Purpose
All pipelines and fittings (tees, bends, valves, fixed supports, compensators) must be equipped with signal conductors. With the help of signal wires (a signal is transmitted through them - a current or a high-frequency pulse) the condition of the pipeline is determined.
Technical specifications
Conductor Configuration
The signal wires, installed inside the thermal insulation layer of polyurethane foam, are pulled parallel to the pipe being manufactured and geometrically positioned at “3” and “9” or “2” and “10” o’clock.
Functional purpose of conductors
The wires being installed are absolutely identical, but according to their purpose they are divided into main and transit wires.
The main wire is a signal conductor that enters all its branches during installation of the heating main. This wire is the main one for determining the condition of the pipeline, as it follows its contour.
A transit wire is a signal conductor that does not enter any branch of the heating main, but runs along the shortest path between the starting and ending points of the pipeline and mainly serves to form a signal loop.
Installation of conductors during construction
During the construction of a heating main, the installation of conductors is carried out at the butt joints of the pipeline.
The installation of the wires must be carried out in such a way that the main signal wire is to the right in the direction of water supply to the consumer on all pipelines, and all side branches must be included in the break of the main signal conductor. It is prohibited to connect side branches to the transit wire.
Connecting wires at joints
The signal wires are connected to each other accordingly: main to main, and transit to transit.
Using pliers, the wires twisted into a spiral are carefully straightened and stretched and, without allowing kinks, are arranged parallel inside.
The wires are cleaned with sandpaper to remove any remaining foam and paint, and then thoroughly degreased.
The wires should be tensioned and excess parts should be cut off so that there is no slack when connecting.
Insert the ends of the wires into crimp sleeve and crimp the sleeve on both sides using crimping pliers.
After this, the resulting connection must be tinned using inactive flux, POS-61 solder and gas soldering iron(or electric, if there is a 220V power supply) the connection of the wires is heated with a soldering iron, after a few seconds it heats up to the melting temperature of the solder.
The connection is sealed correctly when the solder fills the ferrule on both sides.
To check if the connection is correct, you need to pull the signal wires to check if the splice is ok.
Press the wires into the special slots into the wire holders previously attached to the metal pipe.
UEC system designed for continuous or periodic monitoring of the condition of the thermal insulation layer and detection of places where the insulation is moistened. The appearance of moisture may be due to damage to the outer polyethylene sheath or leakage of coolant from the steel pipe due to corrosion or defects in welded joints.
SODK allows you to control the quality of installation and welding of a steel pipeline, factory insulation, work on insulating butt joints, prevent accidents during the operation of the heating pipeline and, ultimately, ensure long-term, reliable and safe work heating networks.
SODK is mandatory element(included in GOST 30732-2006) pipelines in polyurethane foam insulation.
SODK the cost is only 0.5-2% of total cost object depending on the order volume. One device (portable detector) can monitor several objects.
The system includes:
- signal conductors in the heat-insulating layer of pipelines running along the entire length of the heating network;
- terminals for connecting devices at control points (central heating center, boiler room, carpet) and switching signal conductors;
- cables for connecting signal conductors to terminals at control points, as well as for connecting signal conductors in pipeline sections where non-insulated elements are installed;
- portable detectors (9 V) for periodic and stationary detectors (220 V) for continuous monitoring;
- locators (pulse reflectometers) - devices for determining the exact location of damage or leakage;
- insulation testers.
IN UEC "MosFlowline" system the principle of operation is laid down NORDIX(used in 95% of all existing European systems). The system is based on measuring the electrical conductivity of the thermal insulation layer, which changes with changes in humidity. To find fault locations (moistening of polyurethane foam insulation, breaks in signal conductors), methods and instruments based on pulse reflectometry are used.
The advantages of this method are its applicability for a wide range of insulation moisture and the ability to search for broken signal conductors in several places.
Our company has developed and supplied its own devices of the UEC system: portable and stationary detectors, terminals with plug connectors, as well as new generation detectors with 4 levels of moisture indexing, which allows you to monitor the dynamics of development emergency situation and assess its severity. The detector has no analogues in the world.
Specialists of the SODK department perform the following work:
- periodic monitoring of the condition of signal conductors during the period of isolation of butt joints and troubleshooting;
- extension of cable outlets and installation of terminals and control devices at control points in accordance with the SODK project;
- inspection of the installed SDSK with the preparation of the corresponding report on readiness for delivery;
- joint acceptance and transfer of the system to the operating organization with the construction company;
- consultations on SODK representatives construction company;
- search for system damage during the warranty period at the request of the operating organization.
