Process engineering includes both simple and complex tasks. Naturally, we spend more time thinking about how to do complex jobs instead of simple ones. That can be a mistake. Even simple tasks need to be done correctly to be useful. We should be proud of our industry's ability to master complex processes, but we need to keep our eyes on the simple tasks as well. Even simple tasks require practice and knowledge.
In our industry, using a vacuum manometer provides a good example. Nothing seems simpler than attaching a manometer to measure vacuum pressures. Nevertheless, many vacuum pressure readings are wrong. When looking for pressure drops of a few millimeters (mm) of mercury, being off by 1 or 2 mm is a big problem. The discussion covers three of the basic causes of incorrect readings; holding the manometer at an angle; water in the manometer; and leaking connections.
Electronic version available in Adobe Acrobat PDF format file A010.PDF 238k.