Western Valve Logo
(661) 327-7660

 

 
20 Years
Western Valve Inc. Inventory
Inventory Stock Items
Western Valve Inc. stocks DAN-EX and other major OEM parts.  Call us to find out if we've got what you need.

What is Double Block and Bleed?

API 6D defines a double-block-and-bleed valve (DBB) as a "single valve with two seating surfaces that, in the closed position, provides a seal against pressure from both ends of the valve with a means of venting/bleeding the cavity between the seating surfaces." The 2008 note points out that this valve does not provide positive double isolation when only one side is under pressure.

By contrast, API 6D defines a double-isolation-and-bleed valve (DIB) as a "single valve with two seating surfaces, each of which, in the closed position, provides a seal against pressure from a single source, with a means of venting/bleeding the cavity between the seating surfaces." The note adds that this feature can be provided in one direction or in both directions. -Valve Magazine

Read the full article "True Meaning of Double Block and Bleed" at www.ValveMagazine.com

www.westernvalve.com - (c) Copyright 2008 Western Valve, Inc.