Why should a shut-off valve not be installed at the top of the tower?
Thread Content
Dear all**, I’ve always been confused as to why cut-off valves should not be installed at the top of the tower Some say it is to reduce drag, but I don’t think that amount of drag has that much of an impact; so what is the real reason behind it?
Who would go to the top of the tower to operate it? Besides, there’s no time to do it even in an accident situation. Increasing another valve at the same time will also add leakage points.
Large-diameter valves are very expensive; from an economic perspective, it is best not to use them – savings should be made wherever possible. For example, no shut-off valves are needed on the pipeline from the reboiler outlet to the tower, and years of experience have shown that it is also safe and reliable to omit shut-off valves at the top of the tower.
But some owners also prefer to add it, as it allows the tower to be isolated and makes it easier to handle
If you want to isolate it, just remove the flange connection at the tower top outlet, right?
"If removing the flange connection can achieve isolation, then there would be no need for any valve manufacturers at all.
The pressure drop isn’t that significant; the main consideration is economic factors. Options such as DN350 butterfly valves or gate valves are available, but emergency shutdown operations are not convenient
1. Generally, the pipelines at the top of the tower are very large in diameter; for economic reasons, a shut-off valve is not installed directly at the top of the tower. 2. It is inconvenient to operate and maintain it; these days it’s rare to see situations where the entire tower has to be taken apart for maintenance. And if that valve breaks, it can be a real hassle ； 3. If cut-off valves are installed, they are mostly placed at small-diameter locations such as the inlet of the vacuum pump and the inlets and outlets of heat exchangers, which facilitates operation and maintenance ；