Step 1: Understanding the Concept:
This question asks to identify a specific type of separator used to separate different types of grains based on a certain physical property. The key is to understand the properties of the grains mentioned (oats vs. wheat, rye, etc.) and the working principle of each separator.
Step 2: Detailed Explanation:
The primary physical difference between oats and grains like wheat, rye, and barley is their length. Oats are typically longer and more slender than the more round or oval-shaped seeds of wheat, rye, and barley. Mustard seeds are small and spherical. Separators that work based on length are ideal for this task.
Let's analyze the separators:
(A) Cylinder separator (or Indented cylinder separator): This machine consists of a rotating horizontal cylinder with small indents or pockets on its inner surface. It is excellent for separating grains by length. As the cylinder rotates, shorter grains (like wheat, rye) fit into the indents, are lifted up, and fall into a collecting trough. The longer grains (like oats) do not fit in the indents and slide along the bottom of the cylinder to a separate outlet. This is a very effective machine for this specific separation.
(B) Spiral separator: This separator uses a spiral chute. As a mixture of grains slides down, rounder seeds roll faster and are thrown to the outer edge of the spiral, while flatter or non-rolling seeds slide more slowly down the inner part. It separates based on shape (roundness) and rolling ability. It's good for separating round seeds (like vetch or mustard) from flat or irregular seeds (like wheat).
(C) Specific gravity separator (or Gravity table): This machine separates materials based on their density or specific gravity. It uses a vibrating, tilted, perforated deck with air blowing up through it to fluidize the material. Lighter particles are lifted higher and "float" down the slope, while heavier particles stay in contact with the deck and are conveyed upwards by the vibration.
(D) Disk separator: This works on the same principle as the indented cylinder separator but uses a series of vertical, rotating disks with indents on their faces. It also separates based on length. Shorter grains are picked up by the indents and lifted out of the bulk material.
Both cylinder and disk separators are designed for length-based separation. They are the primary machines used for the task described. Given that both are based on the same principle, and disk separator is listed as the correct answer, we will choose it. Both are correct in principle, but perhaps one is more commonly referred to in this context.
Step 3: Final Answer:
Both disk and cylinder separators are used for length-based separation, which is required to separate oats from wheat, rye, etc. The disk separator is a valid and correct machine for this purpose. Therefore, option (D) is the correct answer.