sTEm–at-Work Answer Puzzle #34: Valve Selection for OJ transfer

An immediate lesson from this puzzle is the realization that slope values of a curve transmit technical information. In this case, the butterfly valve allows about 5% of the maximum flow when the valve is 30% on the way to completely open. However, the other valve at the same 30% open position will permit about 45% of the maximum flow through the valve. From the opposite perspective, the curves also indicate at the 50% fluid flow position, the butterfly valve has to be 70% open, but the other valve only needs to be about 32% open.  
The puzzle also provides a segway for an introduction to valves. In this case, the Butterfly valve is a common  rotating valve while the other valve is actually a stem driven valve that goes up/down to open/close the flow channel. There is enough Google based information with pictures of various valves to make a PowerPoint presentation. For more advanced students, valve components (trim, etc,) and valve coefficient, Cv, can be introduced as well.       

The technician installed the “U-Becth-Em V222.   Answer: NO