DeZURIK BOS-US Resilient Seated Butterfly Valves



DeZURIK BOS-US Resilient Seated Butterfly Valves

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Wide Range of Applications
BOS-US Resilient Seated Butterfly Valves are designed to handle a wide variety of liquids and gasses. The uninterrupted seat BOS Valve is desirable for applications where extended service applications are necessary such as high cycles, high pressures and high temperatures. BOS-US valves are excellent choices for continuous modulating control, dead-end service to 250 psi, and vacuum service to 24″ Hg. In thousands of installations worldwide, DeZURIK BOS-US Valves have a proven record of long-term reliability, throttling control, value-added design features and unmatched economy.

Uninterrupted Seat Design
By using an off-center disc, BOS Valves have an uninterrupted seat design for improved seating performance, resulting in longer seat life. The BOS-US uninterrupted seat design assures dead-tight shutoff in isolation and dead-end service without requiring downstream flanges. BOS-US Valves have integral flange seals, eliminating the need for flange gaskets.

Superior Bonded Seats
The BOS-US seat bonding process provides a long-lasting, maintenance free seal. Seats are bonded to the body, holding the seat firmly in place and eliminating premature seat failure that can occur due to flexing and fatigue. The bonded seat also improves performance when the line maintains a vacuum, or when handling viscous liquids – circumstances that tend to dislodge seats that are not solidly retained in the valve body.

Bearings for Reliable Operation
Three heavy-duty bearings ensure smooth, reliable valve operation and promote a longer cycle life than valve designs without bearings. They are fit into the valve body to support shaft loads and eliminate binding. Shaft seals protect bearings from internal and external corrosion.

Shaft Seals for Maximum Reliability
The BOS-US shaft sealing technology offers maximum reliability. It uses four separate sealing components for continuous protection from leakage. Disc hubs form the primary seal around the shaft. Two additional seals are molded into the seat to ensure reliability.

Blowout Proof Shaft
BOS-US Valves feature a rugged, splined disc-to- shaft connection. This provides high cycle life and great control performance. Shaft diameters meet AWWA 504 Class 75B standards. For user safety, each valve has a blowout proof shaft per API 609 standard.


2-36″ (50-900mm);
up to 42″ (1050mm) on application

to 250°F (121°C)

2-20” (50-500mm)
250 psi (1720 kPa) with ductile iron/nickel plated disc;
200 psi (1380 kPa) with 316 stainless steel disc
24-36″ (600-900mm)
175 psi (1210 kPa)

Bubble-Tight, full rated bi-directional shutoff; lugged valves provide dead end service to full valve rating.

Wafer or lugged

2-20” (50-500mm) ductile iron;
24-42” (600-900mm) cast iron

Lever, handwheel, chainwheel, square nut, PowerRac double-acting and spring- return cylinder, G-Series cylinder


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