Tennessee Wastewater Operator Practice Exam

What is used to determine if the gate valve seats fit properly?

1. Liquid soap

2. Prussian blue

3. Measuring tape

4. Water pressure

The correct answer is: Prussian blue

The use of Prussian blue in determining whether gate valve seats fit properly is a standard practice in maintenance and inspection procedures. Prussian blue is a dye that is applied to the valve seat area. When the valve is closed, if there are any gaps or irregularities in the seat, the dye will show where the material has not made proper contact. This visual cue makes it clear whether the seating surface is adequately sealing, which is crucial for preventing leaks and ensuring the efficient operation of the valve. This method is advantageous because it provides a straightforward, quick way to identify problems without needing to disassemble the valve extensively. By applying the dye, operators can directly observe the effectiveness of the seal, allowing for prompt maintenance or replacement if necessary. The other choices, while they may have applications in different contexts, do not specifically address the evaluation of gate valve seat fitting as effectively as Prussian blue does.