Pipeline systems, being a system for transporting expensive and often hazardous substances, require protection from environmental influences. One of the means of protection in this case is insulating flange connections.
An insulating flange joint is a design often used in pipelines, consisting of three flanges, between which a paronite gasket PON-B is used as an insulating seal. The flanges are connected to each other using studs, which in turn are also isolated from the flange using fluoroplastic bushings. The insulating flange connection design also includes three screws for connecting electrical instruments.
An insulating flange joint is a pipeline element designed to protect the pipeline from stray currents - the so-called electrochemical corrosion. The problem of electrochemical corrosion is acute in the operation of pipelines laid underground. Stray currents, penetrating into pipes that do not have reliable insulation, are safe at the entrance, but create a dangerous anode zone at the exit, in which the metal is gradually destroyed under the influence of electric current. Subsequently, cracks may appear in the system, which can lead to leaks and accidents in the pipeline system.
In the production of IFS, slates from steel 09g2s, gaskets and bushings made of fluoroplastic, hardware from steel 40x (according to GOST 12816) are used.
Cases when the IFS is installed:
• at the branches of pipeline sections from the main pipeline;
• near objects of probable sources of stray currents, such objects can be power substations, tram depots, repair bases;
• when installing the pipeline if its parts are made of different metals;
• to disconnect an isolated pipeline from various potentially dangerous structures or at the entrance to such facilities;
• at the outlet of the pipeline system from the supplier's territory and at his entrance to the consumer's territory;
• on vertical elevated sections of inputs and outputs of gas distribution points and gas distribution stations.
An insulating flange connection is made of two flanges manufactured in accordance with GOST 12820-80 or GOST 12821-80.
In a design in which flanges according to GOST 12820-80 are used, to ensure non-separable assembly of connections, steel pipes are welded to the flanges when assembling the connections. This allows welding of joints without fear of overheating, loss of tightness or loss of electrical insulating properties.
