Výrobní program O firmě Certifikáty Ceník Kontakty
1. Pre-insulated Pipeline Systems
Introduction – General Information
Applied Materials
Medium-Conducting Pipeline
Insulating Layers
Outer Protective Layers
Pipeline and Fittings
PIP 130 A, B, C
PIP 180 A, B, C
PIP 210, 240, 270
PIP 300 A, B, C
Elbows, Branches, Reducers, Compensators, Fixed Points
Accessory Parts - Entries, Pipeline Ends, Expansion Cushions
Mounting Instructions for Pipeline Connection, Coupling Design
Safety Regulations
Handling, Storage
Planning Activity Documents
Earth Works
Thermal Losses of Distribution Systems – k-Coefficient
Heat Dilatation PIP
Solution of Heat Dilatation
Compensating Bodies L, Z, U
Heat Tensioning of Pipeline
Axial Compensators
Steam Distribution System
Installation Length, Friction Forces, Pipe Cross-Sections
2. Production Assortment of the Company IZO

Monitoring System

High lifetime and efficiency of the pre-insulated systems is conditioned by protection of insulating layers against humidity, which can cause impairment of thermal-insulating properties of the system and corrosion of the heat-carrying pipe. Therefore, the pipe distribution systems are equipped in case of request with read-select lines that allow permanent monitoring of the whole system. The actual monitoring device supervises the network state and in case failure, whether caused by damage of the coat (PE protection pipe), eventually leakage of the welded joint and the like, it warns of state change. At localization of the point of fault on time it is possible to avert extensive damages.

The pre-insulated pipeline may be equipped with two types of monitoring systems according to the fault localization method: 
1. working on principle of ratio electric resistance method
2. working on reflectometric measuring principle

Both types use different electric conductivity of dry and wet polyurethane foam for check.

In addition to impairment of the insulation state, the systems indicates faults of the own measuring loop – its break or short circuit to metal part of the pipeline.

For exact and quick error localization it is necessary to have also a wiring diagram of signalling wires in addition to laying plan of the routing.

Use of the monitoring systems offers a series of procedures:

a) The monitoring system is finished in check points, where regular measuring can be performed periodically with one monitoring device.

b) The monitoring system is led to one measuring point, where monitoring is preformed permanently.

c) The monitoring point is equipped with a complex unit, i.e. monitoring and also bearing one, e.g. computer controlled, and it carries out a test in pre-programmed time periods including printing of found state provided with time data and the like.

For both systems it is possible to use only the monitoring unit as a basic unit. The bearing unit is more perfect, it carries out also bearing of the point of fault in addition to monitoring itself.

a) Monitoring system with the use of ratio (bridge) electric resistance method

The classic example is the monitoring system Brandes, when the pipeline is equipped with two wires made of resistance material. The sensor wire is made of material NiCr - diameter 0.5 mm, provided with teflon insulation, which is perforated by 13 mm. Electric resistance of this wire is 5.7 Wm-1. The return wire is made of tinned copper with diameter of 0.8 mm and is provided with teflon insulation.

Localization of defective insulation

The localization result indicates in percents a distance of faults from the sensor wire beginning to the point of fault on a connected pipe length.

For localization on the sensor loop between the sensor wire beginning and end the localization voltage (Uges) is set. This one is divided on high-ohmic sensor wire with a humidity error into two partial voltages (U1 a U2).

The partial voltage U1 between the sensor wire beginning and the humidity error can be measured on the sensor wire beginning between the sensor wire and the metal pipeline and shows a localization result.

Following formula is valid: 


X %

100 %

where:  U1  =  partial voltage between the sensor wire beginning and the fault
Uges  =  total localization voltage
R1  =  partial resistance of the sensor wire up to the fault
Rges  =  total resistance of the sensor wire
X %  =  localization result in percents
l  =  fault distance (measured on the sensor wire)
L  =  total pipeline length
Fault distance l is calculated this way:       l = 
L . X %


Connecting of wires

Installation conditions:  - potrubí musí být očištěno
- The pipeline must be cleaned.
- The monitoring wires may not be damaged.
- Company's original components are to be used.
- All must be dry before joint foaming.

Connecting of wires is carried out with a pressing coupling and the coupling itself is secured with a contractible tubing.

With the installation device MH-2, each partial section (joint) is checked at assembly of the loop. This installation device signals, in addition to the actual loop length, eventual interruption or defective connection of wires and secures eventual humidity degree in a fourteen-stage scale.

The personnel of companies performing installation of the monitoring system BRANDES must be instructed by this company.

b) Monitoring system working on reflectometric principle

In contrast to the previous type two wires are foamed in the insulating layer – a tinned copper one and a copper one with cross section of 1.5 sq. mm. For actual function of the monitoring system the tinned wire has no importance. From the device functionality viewpoint two copper wires can be used. Importance of this identification consists in facilitation of installation itself for securing of the system functionality. It is important to observe the procedure of wire interconnecting at parallel branches, T-pieces and the like.

The reflectometric check principle itself consists in transmitting of high-frequency pulses that partially reflect in the point of fault. These reflected pulses are evaluated.
The system can be used for particular branches of the distribution system up to 1,000 m.

Connecting of wires

Installation conditions are identical as in the previous description.

In principle there are connected:  Cu + Cu
ZnCu + ZnCu

In the first instance, the wires will be straighten and checked, whether they are not partially broken. After that, the wires will be thread through the coupling and will be screwed so that no contact with steel pipe can occur - thus tensioned. Otherwise, an underlay under the wires must be used. The overhanging free ends of wires will be removed.
For elimination of high contact resistances the coupling will be soldered without use of acid – not with flame.

In the course of connection, each partial section (joint) of the routing must be checked.

The company performing assembly, i.e. connection, must be instructed for this operation!!!

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