Question:
In a ............ evaporator, the circulation of liquid occurs with the central down comer.
In a ............ evaporator, the circulation of liquid occurs with the central down comer.
Show Hint
The central downcomer in a vertical tube evaporator is essential for "natural circulation." Without it, the liquid wouldn't return to the bottom effectively to be reheated.
Updated On: Aug 7, 2026
- Horizontal tube
- Vertical tube
- Thin Film
- Multiple effect
Show Solution
Verified By Collegedunia
The Correct Option is B
Solution and Explanation
Step 1: Understanding the Question:
The question relates to the design of evaporators used in the food industry. It specifically describes an evaporator where liquid circulation is facilitated by a central conduit known as a "down comer."
Step 2: Detailed Explanation:
• Vertical Tube Evaporators: Also known as short-tube vertical evaporators or "Standard" evaporators, these consist of a bundle of vertical tubes (calandria) through which the liquid flows.
• Central Downcomer: In this specific design, a large diameter tube is placed in the center of the tube bundle. This is the "central downcomer." The area of the downcomer is typically about 40% to 100% of the total cross-sectional area of the heating tubes.
• Circulation Mechanism: When steam heats the liquid in the smaller tubes, the liquid boils and rises due to decreased density (thermosiphon effect). The cooler, denser liquid in the large central downcomer flows downward to replace it. This creates a natural circulation pattern that enhances heat transfer and prevents local overheating.
• Applications: These are widely used in the sugar industry and for concentrating non-viscous liquids.
• Other Evaporators:
• Horizontal tube: Steam is inside the tubes and liquid is outside; it does not feature a central downcomer for liquid circulation.
• Thin Film: Uses mechanical agitation or gravity to spread a thin layer of liquid on a heated surface.
• Multiple effect: Refers to a system of evaporators connected in series, not a specific internal tube geometry.
Step 3: Final Answer: The vertical tube (short-tube) evaporator is the one characterized by a central downcomer for natural circulation.
The question relates to the design of evaporators used in the food industry. It specifically describes an evaporator where liquid circulation is facilitated by a central conduit known as a "down comer."
Step 2: Detailed Explanation:
• Vertical Tube Evaporators: Also known as short-tube vertical evaporators or "Standard" evaporators, these consist of a bundle of vertical tubes (calandria) through which the liquid flows.
• Central Downcomer: In this specific design, a large diameter tube is placed in the center of the tube bundle. This is the "central downcomer." The area of the downcomer is typically about 40% to 100% of the total cross-sectional area of the heating tubes.
• Circulation Mechanism: When steam heats the liquid in the smaller tubes, the liquid boils and rises due to decreased density (thermosiphon effect). The cooler, denser liquid in the large central downcomer flows downward to replace it. This creates a natural circulation pattern that enhances heat transfer and prevents local overheating.
• Applications: These are widely used in the sugar industry and for concentrating non-viscous liquids.
• Other Evaporators:
• Horizontal tube: Steam is inside the tubes and liquid is outside; it does not feature a central downcomer for liquid circulation.
• Thin Film: Uses mechanical agitation or gravity to spread a thin layer of liquid on a heated surface.
• Multiple effect: Refers to a system of evaporators connected in series, not a specific internal tube geometry.
Step 3: Final Answer: The vertical tube (short-tube) evaporator is the one characterized by a central downcomer for natural circulation.
Was this answer helpful?
0
0
Top ICAR AIEEA Food Science and Technology Questions
- What is the typical bond angle between hydrogen and oxygen atoms in a water molecule?
- Which conditions are favorable for the formation of acrylamide in foods?
Match List-I with List-II.
List-I (Chemical Compound) List-II (Source) (A) Inulin (I) Acacia tree (B) Sodium Alginate (II) Red algae (C) Gum arabica (III) Chicory root (D) Carrageenan (IV) Brown algae Choose the correct answer from the options given below.
- Arrange the following HACCP principles in the correct sequence as per their implementation:
(A). Conduct a hazard analysis
(B). Establish critical control points (CCPs)
(C). Establish corrective actions
(D). Establish monitoring procedures
(E). Establish verification procedures
(F). Establish record-keeping and documentation procedures
Choose the correct answer from the options given below: - Which of the following flavonoids is incorrectly grouped with its food source?
(A). Naringin-Citrus
(B). Quercetin-Onion
(C). Kaempferol-Broccoli
(D). Genistein-Berries
Choose the correct answer from the options given below:
View More Questions
Top ICAR AIEEA Food Safety Questions
- Arrange the following HACCP principles in the correct sequence as per their implementation:
(A). Conduct a hazard analysis
(B). Establish critical control points (CCPs)
(C). Establish corrective actions
(D). Establish monitoring procedures
(E). Establish verification procedures
(F). Establish record-keeping and documentation procedures
Choose the correct answer from the options given below: - HACCP principles were introduced by which of the following organizations?
- --------- is a spanish wine, matured at high temperature by placing the filled barrels for 3 to 4 months.
- The fermented fish product called Ngari is from _______
- Vibrio parahaemolyticus can grow in _______ NaCl.
View More Questions
Top ICAR AIEEA Questions
- Which of the following statements is false?
- Which of the following is an example of an inventory?
- According to Adam Smith, productivity gains could be brought about through .
- The supply curve for an artificially scarce good is .
- Which of the following would not be considered an opportunity cost of paid employment?
View More Questions