Incorrect valve's schedule

Monday, July 20, 2009

As i've ever wrote for some incorrect things while in fabrication process, in this article, i'd like to tell you what should you do while you've got incorrect valve's schedule. For example, the supplied valve is sch.80, meanwhile the pipe is sch.160.

Valves used to be field assembled. For some reason, our site representative prefer to modify the valve then to wait the resupplied valves delivered to the site. Since the pipe is a calculated part, so it is important to not to do anything with the pipe. Don't remachining the end pipe to make it meet with valve sch. (sch.80 in this case). The first thing we've to do is make a discussion with the valve supplier.
Ussually, they will advise to built up and then machining the end valve to meet with the pipe sch. (sch.160 in this case). The other recommendation is mill back the end valve to meet the pipe sch. (sch.160 in this case).
The first option takes more resources and expensive, but we can maintain the end to end valve length. Meanwhile, the last option takes short time and a few resources, but we've to add a short spool between the modified valve and the origin pipe, since the end to end valve length isn't as the original size.
So, hopefully you can resolve all issues occur with the incorrect valves.