10.1 Leak detection system

The aim of using an electric insulation control system

With the help of the electronic control system built in the preinsulated pipe system it is easy to check the sta­tus of the insulating layer constantly. The fact that the insulating layer is soaked and the exact place of the leak can be determined exactly, either it is a result of the damaged outer coating or the result of the back of proper sealing on the inner pipe.

Operation

When the insulating layer is soaked the thermal char­acteristics of the material change together with it's insulating resistance. The control system detects the change in the insulating material's electric insulating resistance at the place of the leak. With the help of this resistance change detector it is possible to determine not only the mere fact of the leak but even the exact place of it. The electric control system can both be installed for continuous and temporary operation. Considering the length of a pipeline, it is advisory to set up controlling loops of a few hundred meters that are independent of each other there is an electric resis­tance at each binding of the pipeline, at both ends of the pipes. These resistances highly influence the length of the loops, because the number of resistances with­in a loop cannot exceed 100.

The main components of the control system:

Control system for temporary use

In this case both ends of the control loop end in plugs which are positioned in a shaft or some other suitable place for storage. The control process is carried out with a portable control device, which shows the exact place of the error.

Control system for continuous use

The control loops are connected to built-in measuring devices, so it is possible to maintain a control method that is based on continuous monitoring. This has got more advantages with widespread and more compli­cated pipe systems. In this case the signal of a leak goes to a center. The exact place of the leak is deter­mined with a portable device.

Installation

These electronic control systems can be built into ISO­IJ~R- compatible preinsulated pipe systems. Besides that they might also be used to control some other types of pipelines.