Question

The output capacity and cleaning efficiency of a wheat thresher at an optimal operating condition are 600 \(\text{kg}\cdot\text{h}^{-1}\) and 99%, respectively. The grain-straw ratio of the crop is 2:1. If the grain recovery at main grain outlet is 100%, the throughput capacity will be

• A. 909 \(\text{kg}\cdot\text{h}^{-1}\)
• B. 900 \(\text{kg}\cdot\text{h}^{-1}\)
• C. 891 \(\text{kg}\cdot\text{h}^{-1}\)
• D. 882 \(\text{kg}\cdot\text{h}^{-1}\)

Hint:

A ratio of 2:1 means grain makes up 2/3 of the crop, and straw is 1/3.
If 2 parts = 600 kg/h, then the total of 3 parts must equal 900 kg/h.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Throughput capacity represents the total rate of unthreshed crop (grain + straw) fed into the thresher.

Step 3: Detailed Explanation:
Given values:
- Clean grain output rate = \(600\text{ kg}\cdot\text{h}^{-1}\)
- Grain recovery at main outlet = \(100\%\)
Since the grain recovery is 100%, the total grain intake rate must equal the output clean grain rate:
\[ \text{Grain feed rate} = 600\text{ kg}\cdot\text{h}^{-1} \] The grain-to-straw ratio of the crop is given as 2:1:
\[ \frac{\text{Grain Weight}}{\text{Straw Weight}} = \frac{2}{1} \] Using this ratio, calculate the straw feed rate:
\[ \text{Straw feed rate} = \frac{\text{Grain feed rate}}{2} = \frac{600}{2} = 300\text{ kg}\cdot\text{h}^{-1} \] The total throughput capacity is the sum of both grain and straw rates:
\[ \text{Throughput capacity} = \text{Grain feed rate} + \text{Straw feed rate} \] \[ \text{Throughput capacity} = 600 + 300 = 900\text{ kg}\cdot\text{h}^{-1} \]

Step 4: Final Answer:
The correct option is 2, which corresponds to 900 \(\text{kg}\cdot\text{h}^{-1}\).