Q41: In the schematic shown below for a reciprocating compressor, which one of the following will you agree with:
A. Valve A protects the machine from surging
B. Valve A maintains a minimum suction pressure
C. Valve A keeps the machine from having higher discharge temperature
D. Valve A, when open, wastes the compressor power
B,C & D; There is no surge in a reciprocating machine. Recycle valve opens to fill the compressor cylinder volume to maintain the minimum suction pressure. Compressed gas is recycled to be compressed again and hence, there is a waste of power.
Q42. A starbucks outlet in my area has recently started giving its customers a free coffee in exchange of four empty coffee cups returned. A group of students have collected 61 empty coffee cups this month.
How many free coffees can these students get by returning these cups?
20; from 60 cups they can get 15 cups while one empty cup would still remain to be returned. Then, from these 15 cups and the remaining cup, 4 more coffees can be obtained. In the end, one more free coffee could be obtained by returning these 4 cups.