Question 259General Subjects - Assistant Engineer

70% to pass

In the illustrated huddling-chamber safety valve, what statement is true concerning the opening and closing forces acting upon the disc? Illustration SG-0018

Diagram for USCG General Subjects Assistant: In the illustrated huddling-chamber safety valve, what statement is true...

AThe spring force acting upward on the disc is a valve opening force, and the sensed pressure acting downward on the disc is a valve closing force.

BThe spring force acting upward on the disc is a valve closing force, and the sensed pressure acting downward on the disc is a valve opening force.

CThe spring force acting downward on the disc is a valve opening force, and the sensed pressure acting upward on the disc is a valve closing force.

DThe spring force acting downward on the disc is a valve closing force, and the sensed pressure acting upward on the disc is a valve opening force.

AI Explanation

The correct answer is C. The spring force acting downward on the disc is a valve opening force, and the sensed pressure acting upward on the disc is a valve closing force. This is because the spring force works to push the disc open, while the sensed pressure works to push the disc closed, in order to maintain the desired pressure in the huddling-chamber safety valve. The other options are incorrect because they describe the forces in the opposite way. The spring force should act to open the valve, not close it, and the sensed pressure should act to close the valve, not open it.