Proper distance for the elbow
Proper distance for the elbow
(OP)
Hi!!!
We have two throttling valves for Continuous Blow Dwon station (CBD) which is between a steam drum and a blow down tank. The steam drum is pressured with 1900psig and the blow down tank vent to atmosphere.
There is elbow after the trottling valve at the CBD station.
I am looking for proper distance between the throttling valve and elbow. I worry about erosion of elbow by high pressure steam flow, but couldn't find proper information to prevent that.
I was told by Conval valves' representative that thumb of rule for the eblow distance could be 3ft per 1 inch of valve outlet diameter. My current stations have 1ft/in and there are minor erosion in the elbows.
I was wondering if one of you could tell me code recommendation or design criteria for the issue.
We have two throttling valves for Continuous Blow Dwon station (CBD) which is between a steam drum and a blow down tank. The steam drum is pressured with 1900psig and the blow down tank vent to atmosphere.
There is elbow after the trottling valve at the CBD station.
I am looking for proper distance between the throttling valve and elbow. I worry about erosion of elbow by high pressure steam flow, but couldn't find proper information to prevent that.
I was told by Conval valves' representative that thumb of rule for the eblow distance could be 3ft per 1 inch of valve outlet diameter. My current stations have 1ft/in and there are minor erosion in the elbows.
I was wondering if one of you could tell me code recommendation or design criteria for the issue.





RE: Proper distance for the elbow
1. DO NOT use elbows in Continuous Blow Down service
2. Use Pipe Bends with a radius of 5 times the nominal diameter of the pipe.
RE: Proper distance for the elbow
What is the schedule of the piping that you are using ?
What is the material ?
Pennpiper is correct about the 5D bends, however wall thickness and material selection are also important
-MJC