Question

………………….. are more frequently used in high pressure, low capacity applications and can handle highly viscous liquids.

• A. Centrifugal pumps
• B. Diaphragm pump
• C. Progressing cavity pumps
• D. Positive displacement pumps

Hint:

If you need to pump peanut butter or molasses at a steady rate against high pressure, always choose a Positive Displacement Pump. Centrifugal pumps will simply "spin" without moving much fluid in these cases.

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The question asks for a broad category of pumps used in food processing that are characterized by their ability to generate high discharge pressures, operate at lower flow rates (capacities), and efficiently move fluids with high viscosity.

Step 2: Detailed Explanation:

• Pump Classification: Industrial pumps are generally divided into Centrifugal and Positive Displacement types.

• Centrifugal Pumps (A): These work by converting kinetic energy into pressure. They are best for low-viscosity fluids (like water or milk) and provide high capacity at low to medium pressures. Their efficiency drops drastically as viscosity increases.

• Positive Displacement Pumps (PDPs) (D): These work by trapping a fixed volume of fluid and forcing it into the discharge pipe. Because they physically "displace" the liquid, they can generate very high pressures regardless of the fluid's resistance.

• Viscosity Handling: PDPs are ideal for viscous foods like tomato paste, honey, chocolate, or dough. In fact, their efficiency often improves with viscosity because internal leakage (slippage) decreases.

• Specific Examples: Diaphragm pumps (B) and Progressing cavity pumps (C) are actually sub-types of Positive Displacement pumps. While both can handle viscous fluids, the question asks for the broader category that fits the general description.

Step 3: Final Answer:
Positive displacement pumps are the categorical choice for high pressure, low capacity, and high viscosity applications.