Question

Capillary tube is a type of _________.

• A. Condenser
• B. Expansion valve
• C. Evaporator
• D. Compressor

Hint:

A capillary tube is a narrow tube that reduces the refrigerant pressure before the evaporator.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
A vapour compression system has four main parts: compressor, condenser, expansion device and evaporator. The expansion device lowers the pressure of the liquid refrigerant before it enters the evaporator.

Step 2: Key Approach:
The expansion device can be a hand expansion valve, an automatic (constant pressure) expansion valve, a thermostatic expansion valve, or a capillary tube.

Step 3: Detailed Explanation:
A capillary tube is a long, thin copper tube of very small bore.
The liquid refrigerant loses pressure as it flows through this narrow tube because of friction.
So the tube drops the pressure and temperature of the refrigerant, just like a valve does.
It has no moving parts. It is used in domestic refrigerators, deep freezers and window air conditioners.

Step 4: Why the other options are wrong.
The condenser removes heat from the hot vapour and turns it into liquid. A capillary tube does not do this.
The evaporator absorbs heat from the cold space. The compressor raises the pressure of the vapour. Neither of these is a throttling device.

Final Answer:
A capillary tube is a type of expansion valve (expansion device). This is option (B).