Question

A high molecular weight polymer passes through different zones from the hopper to the die in an extruder. Among the options given, identify the correct match between the zones and their key functions.

• A. P-4; Q-3; R-2; S-1
• B. P-3; Q-4; R-1; S-2
• C. P-4; Q-1; R-2; S-3
• D. P-3; Q-1; R-2; S-4

Hint:

Think: \textbf{Feed} (receive) $\Rightarrow$ \textbf{Compression} (melt) $\Rightarrow$ \textbf{Metering} (constant flow) $\Rightarrow$ \textbf{Working/Mixing} (high shear).

Answer 1

The Correct Option is A

Step 1: Recall the function of each extruder zone.
Feed zone (R): closest to the hopper; its job is to receive and convey the pellets/powder. $\Rightarrow$ matches function 2.
Compression/transition zone (Q): solids bed compacts; viscous heating plus barrel heaters melt the polymer. $\Rightarrow$ matches function 3.
Metering zone (P): fully molten polymer is homogenized and delivered at a steady, nearly constant flow rate by the screw. $\Rightarrow$ matches function 4.
Working (mixing) zone (S): special mixing flights/pins/clearances impose high shear for effective mixing. $\Rightarrow$ matches function 1.
Step 2: Compile the mapping.
$P \to 4,\; Q \to 3,\; R \to 2,\; S \to 1$ which is option (A). Final Answer: \[ \boxed{\text{(A) } P\!-\!4,\; Q\!-\!3,\; R\!-\!2,\; S\!-\!1} \]