Dielectric Insulating Unions

Dielectric insulated unions provide dielectric insulation between two dissimilar metals, which prevents galvanic corrosion. Some examples of dissimilar metals are:

Galvanized iron and copper
Carbon steel and stainless steel
Carbon steel and copper
Stainless steel and copper

Should these metals meet in direct contact, corrosion can occur over time. Dielectric insulated fittings ultimately keep dissimilar metals from corroding each other, which is a potential risk for many types of metal pipelines.

In many connections, any acid present in water could cause an electrolytic response between different metals. This could result in the electrons from one metal feeding into another in an electric current. One metal loses molecules and deteriorates, and the other ends up collecting more and more of this by-product the longer the pipes are in use. This is the process of galvanic corrosion, which a dielectric insulated union prevents.

HART O-Ring Union Features:

Turbulence Free: All unions provide a turbulence-free fit across the seats
O-Ring Isolation: The O-Ring seal is strategically located in the thread
piece face eliminating O-Ring media contact and added protection against abrasives and erosion. A variety of O-Rings for any application are available.
Precision Machined Components: All unions are precision machined to provide high quality and fail-safe leak proof reliability.
Interchangeable End Connections: HART’s male threaded connections feature interchangeable configurations with other threaded or welded connections, reducing the need for nipples or additional fittings.
Material Versatility: Unions can be provided in all standard metals or combinations of metals. This includes 304 Stainless, 316 Stainless, A105 Carbon Steel, Brass, Monel 400, Hastelloy, and Titanium.
Excellent Vibration Resistance: Seals will not loosen, even under extreme pressure and pressure surges.
No Maintenance: Once the initial seal is made, no further tightening is required.