Isolation Valves
On-Off Fluid Shutoff Solutions
Overview & Design
Isolation valves are designed to entirely block or permit fluid flow in pipelines. They are characterized by low pressure drop when fully open and are not meant for throttling.
Pedagogical Rationale
Piping systems require positive shutoff boundaries to perform maintenance, isolate plant segments during emergencies, and control sequence routing without leaking fluid downstream.
Standard Industry Applications
Category Valve Types
Wedge Gate Valve
Linear movement wedge sealing against tapered body seats.
A threaded stem drives a metal wedge downwards perpendicular to flow direction, pressing into seats to block fluid.
Floating Ball Valve
Quarter-turn rotary sphere nested in soft polymer seats.
Stem rotates the inner ball 90 degrees. Upstream pressure shifts the ball downstream to compress the soft polymer seal.
Triple Offset Butterfly Valve
Rotary action disc with triple eccentric offset sealing for high performance.
The stem rotates a thin circular disc 90 degrees. The triple offset shaft alignment ensures the disc makes contact with the seat ring only at final shutoff, eliminating seat friction.
Weir Diaphragm Valve
Flexible membrane pressed onto a weir, fully isolating the fluid from the working parts.
A non-wetted stem lowers a compressor onto a flexible diaphragm, flexing it down onto a raised weir to throttle or shut off flow with zero stem leakage.
Lubricated Plug Valve
Tapered quarter-turn plug sealed by an injected lubricant film over full contact.
A wrench rotates a tapered plug 90 degrees so its through-port aligns with or blocks the bore; injected sealant lubricates and renews the seal across the taper.