Minnesota Boiler License Practice Exam

What is the term used to describe the difference between the popping and closing points of a safety valve?

1. Number of minutes the valve operated before closing

2. Volume of steam discharged

3. Difference between the popping and closing points of the safety valve

4. Pressure when valve closes

The correct answer is: Difference between the popping and closing points of the safety valve

The correct term for the difference between the popping and closing points of a safety valve is indeed defined as the difference between these two pressure points. This measurement is crucial because it indicates the range at which the safety valve operates effectively to protect the boiler from excessive pressure. When the pressure in the boiler exceeds the set pressure, the safety valve "pops" open to release steam, preventing potential overpressure conditions. The popping point is the pressure at which the valve opens, while the closing point is the pressure at which the valve reseals after the pressure has decreased. Understanding this difference helps operators ensure that safety valves are functioning properly and that the boiler is operating within safe limits. In contrast, the options regarding the minutes the valve operated before closing, the volume of steam discharged, and the pressure when the valve closes do not specifically capture the definition of the difference in pressure between the opening and closing of the valve. These factors may be relevant in the context of safety valve operations but do not describe the relationship defined by the term in question.