Description

Temperature, pressure, flow, and level are the four most common process variables. Similar to temperature, pressure is another key process variable because pressure provides a critical condition for boiling, chemical reaction, distillation, extrusion, vacuuming, and air conditioning. Poor pressure control can cause major safety, quality, and productivity problems. Overly high pressure inside a sealed vessel can cause an explosion. Therefore, it is highly desirable to keep pressure in good control and maintained within its safety limits.