What is a dielectric union?
Dielectric Union is a term used to describe two -piece fittings of different metals that are electrically insulated from each other to prevent galvanic corrosion. This term is most commonly used to describe the family of water pipe fittings. Galvanic corrosion occurs when two different metals are exposed to acidic solution. This combination effectively forms the battery and causes the electrical flow between the two metals. To prevent corrosion caused by this current, the dielectric union uses an insulating insert between two metals to prevent electrolysis.
When two different metals are placed in contact in acidic solution, electrolysis occurs, causing an ion flow between the two metals. This electric current flow causes molecules from one of the metals to be stored on the other, leading to what is called galvanic corrosion. The metal that donates the molecules will slowly erode away, while the one that receives the material creates a layer of by -product of corrosion. INA number of domestic water sources are slightly distorted pH; Galvanic corrosion is likely to occur anywhere where different metals are used in plumbing fittings. One way to prevent this destructive process is to insulate two parts of fittings apart.
Thedielectric union achieves this insulation with a plastic insert located between two parts of the assembly. Quich fittings usually consist of brass and steel halves to connect similarly different types of pipes. The dielectric union has another plastic or non -conductive fiber sleeve that surrounds the brass part of the assembly and pad to form a flange barrier. The sleeve and pad effectively insulate two materials from each other and prevent the galvanic battery effect. One point to keep in mind when you think this phenomenon is that the voltage connected to the galvanic electrolysis is very small and does not present any danger.
dielectriThe UNI fittings intended for use with copper pipes generally require that the brass part of the Union be burned on the copper tube. The plastic case should be removed from the assembly to prevent melting from this design and replaced only after the brass has cooled. The pad should also move as far as possible on the copper tubing for soldering for the same reason. When the assembly is assembled, it is necessary to ensure that the tearing or destruction of the plastic sleeve is prevented. The small area of contact between the two metals will lead to a much more aggressive localized corrosion than contact with the full area.