HART O-ring Unions are used where piping requirements dictate the necessity of having a flat face seal to make and break the pipe line. They meet requirements where an O-Ring, zero leakage, seal is recommended.

• Turbulence-free fit across seats. Full bore I.D. - Full Flow.
• O-Ring is located in the threadpiece face, well out of the waterway bore providing added protection against abrasives and erosion.
• Combination end connections. Threaded, socketweld and buttweld ends are all interchangeable, as well as one-step line size changes.
• Resistance to vibration. Seals will not loosen, even under extreme vibration or pressure surges.
• No maintenance needed because once the seal is made, it never requires retightening.
• Saves money and weight by eliminating unnecessary nipples, bushings, couplings and inserts when initially built into the system.

At any pressure HART o-rings actually strengthen the seal rather than loosen it.

Static The O-ring is fitted into a machined groove between the two halves of the union. When the halves are drawn together, the O-ring compresses to an ovalized cross-section, forming a positive, resilient seal which serves to block the fluid, thus sealing even at low or no pressure.

Under Load As pressure is increased, the O-ring is forced to flow and is squeezed into the downstream side causing the O-ring to conform to the shape of the end, blocking the groove gap. The more the system pressure increases, the more effective the seal.

Strait-Away Breakout The flat-faced construction allows for slipping the component in and out without disturbing the surrounding tube or pipe sections. Pipe alignment is much easier with HART unions since it is unnecessary to spring the line during make-up or disassembly.

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