Capillary Tube

Published by on

What is Capillary Tube?

The capillary tube is a kind of expansion device in small capacity hermetically sealed refrigeration units, for example, refrigerators, water coolers, room air conditioners, and freezers. It is a copper tube. And, it has a small internal diameter and varying length depending upon the application. It is placed in the liquid line between the condenser and the evaporator. In order to protect from the contamination, fine wire mesh is there at the inlet of the tube. The specification of the tube is: 

  • The inside diameter of the tube is about 0.5mm to 2.25mm.
  • The length varies from 0.5m to 5m.
Capillary Tube Diagram

Tube Diagram

Capillary Tube method

In the process, the liquid refrigerant from the condenser enters the tube. The pressure drops because of internal friction. As the tube has a small diameter. Also, the frictional resistance is directly proportional to the length and inversely proportional to the diameter. Therefore longer the capillary tube and smaller its inside diameter. More will be the pressure drop in the flow of the refrigerant. The greater pressure difference between the condenser and the evaporator is in need of the given flow rate. The diameter and the length of the capillary tube once chose for a given arrangement of conditions and load cannot work effectively at different conditions.


Capillary Tube Refrigeration advantage

The advantages of the tube are;

  1. The cost of the tube is less in comparison with all other types of expansion devices.
  2. Since the refrigerant charge in the narrow tube system is basic, in this way no receiver is important.
  3. When the compressor stops, the refrigerant keeps on streaming in the evaporator evens out the pressure between the high side and the low side. This extensively declines the beginning load on the compressor. Hence we can use low torque motor to define the compressor, which is an incredible advantage.




Leave a Reply

Your email address will not be published. Required fields are marked *