Steam Boilers, Engines, Nozzles and Turbines
The function of a valve rod is

To provide simple harmonic motion to the D-slide valve
To provide reciprocating motion to the slide valve
To convert reciprocating motion of the piston into rotary motion of the crank
To convert rotary motion of the crankshaft into to and fro motion of the valve rod

ANSWER DOWNLOAD EXAMIANS APP

Steam Boilers, Engines, Nozzles and Turbines
In designing air preheaters, the important design consideration is that

Handling and maintenance should be easier
Approach temperature should be as low as possible
Heat transfer area should be optimum
Stack gases should not be cooled to the dew point

ANSWER DOWNLOAD EXAMIANS APP