Machine Design

Stem seal stops ball valve leaks

A common problem in ball valves is a misaligned actuator. If someone steps on the valve or bumps it in the field, or just opens or closes the valve roughly, it could put a side load on the stem and lead to leakage. To prevent this, engineers at Xomox Corp., Cincinnati, designed a spherical seal on its Tuffline ball valve that handles side loads without leaking. It works somewhat like a ball joint to maintain stem seal integrity despite stem movements and wear on sealing components. The precisely machined ball also assures low operating torque for economical actuation and reduced seat wear.

The valves are available in one and two-piece flanged versions, as well as three-piece screwed, socket-welded, and butt-welded versions. Sizes range from 0.5 through 8 in. in ANSI class pressure ratings of 150, 300, and 600 psi. They provide tight shutoff from high vacuum through rated pressures at temperatures of -20 to 450F.

TAGS: Hydraulics
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