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Capillary Copper Tube, Why We Need Super Small Diameter Copper Tube?

What is Capillary Copper Tube

Capillary Copper Tube usually stands for copper tubes have a very small diameter. It could be either straight or coil form, as the condition hard or annealed are both avialable.

Capillary Copper Tube Size

Inside diameter (I.D.) ranging from 0.020~0.175 inches (0.50~4.45mm)

Outside diameter (O.D.) ranging from 0.072~0.24 inches (1.83~6.10mm)

Idea Choice for Precision Tubing 

The simplest in design, lowest in cost type expansion devices of cooling and air conditioning in refrigeration systems is the capillary tube. A capillary tube reduces refrigerant pressure using friction and the acceleration of the refrigerant in the tube[note 1].

Combination of length and diameter of the capillary tube can meet the requirements of various conditions & different cooling capacity of the refrigerant device, however the once capillary copper tube is selected and installed, it can not change with the load changes, in order to make the cooling device In the vast majority of time under the high efficiency of operation. So select a representative design is very important

Due to the excellent features, capillary copper tubes is widely used in precision instrument, air conditioning and refrigeration,  electronic, thermostate, relay and other industries.

Piping Diagrams of Daikin Inverter Pair Wall Mounted Type H-Series[note 2]

Daikin inverter pair ac Piping Diagrams

Chemical and mechanical datas

Material No. Chemical Composition Temper Mechanical Property
Copper % (min) Phosphorus % Tensile Strength (Mpa) Elongation %
C12200 99.9 0.015-0.040 H80 395 /
C12200 99.9 0.015-0.040 O60 ≥205 ≥40


Normal Specifications

Belowing is a table of most common capillary copper tube's specifications that be supplied by Winland. However, if you need customized products, feel free to write to us by and see what we are capable.

Size Cross Sectional
Area of Tube Bore
Quantity per Coil
O.D. I.D.
Inch mm Inch mm Inch² mm² 15m 30m 30kg
0.072 1.83 0.028 0.711 0.0006158 0.397
0.081 2.06 0.031 0.787 0.0007578 0.487
0.087 2.21 0.036 0.914 0.001018 0.657
0.093 2.36 0.042 1.067 0.001315 0.893
0.097 2.46 0.046 1.168 0.001662 1.07  
0.106 2.69 0.054 1.372 0.00229 1.48  
0.112 2.84 0.059 1.499 0.002734 1.76    
0.125 3.18 0.07 1.778 0.00848 2.48    



Foot Notes:

Note 1: Design of an Experimental Apparatus for Studying the Flow of Refrigerant R-134a in a Capillary Tube Refrigeration System, by M. F. G. Johnson and W. E. Dunn, Sept 1993. Orignal source

Note 2: Daikin Inverter Pair Wall Mounted Type H-Series Service Manual