minhvu17
Mechanical
- Sep 10, 2014
- 3
Hi all,
I am very new to valve and pipeline. While reading through the API 6DSS, i have notice about definition of DIB and DBB which im not so clear of
1. Double-Block and Bleed Valve (DBB) – 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. NOTE: This valve does not provide positive double isolation
when only one side is under pressure.
2. Double-Isolation and Bleed Valve (DIB) – 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.
I have several questions which i am seeking for the answers. Hope everyone could help me
1. What are the meaning of "Block" and "Isolation" here? Is this about the function of the valve which is block or isolate?
2. Can someone please explain more about "provides a seal against pressure from both
ends of the valve" and "provides a seal against pressure
from a single source"?
3. "This valve does not provide positive double isolation
when only one side is under pressure". Why is this?
I know my questions sound dumb but since i am new to this, please help. I really appreciate it.
Thank you very much.
I am very new to valve and pipeline. While reading through the API 6DSS, i have notice about definition of DIB and DBB which im not so clear of
1. Double-Block and Bleed Valve (DBB) – 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. NOTE: This valve does not provide positive double isolation
when only one side is under pressure.
2. Double-Isolation and Bleed Valve (DIB) – 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.
I have several questions which i am seeking for the answers. Hope everyone could help me
1. What are the meaning of "Block" and "Isolation" here? Is this about the function of the valve which is block or isolate?
2. Can someone please explain more about "provides a seal against pressure from both
ends of the valve" and "provides a seal against pressure
from a single source"?
3. "This valve does not provide positive double isolation
when only one side is under pressure". Why is this?
I know my questions sound dumb but since i am new to this, please help. I really appreciate it.
Thank you very much.