Table of Contents
Advertisement
Available languages
Available languages
5. Connecting refrigerant pipes and drain pipes
5.1. Pipe connecting method
Brazing
Caution:
Keep the flame out of contact with the cables and metal sheet when brazing the pipes.
- Failure to do so may result in burnout or malfunction.
When connecting pipes, satisfy the minimum insertion depth requirement for copper pipe joint, and the gap between the pipe outer wall and the joint inner wall as follows.
B
•
Silver braze the pipes in corrosive environments such as in which the concentration of sulphurous acid gas is high.
•
Do not use a low-temperature brazing material as it is not strong enough.
•
When re-brazing the connections, use the same brazing material.
•
Paint the brazed sections after brazing.
• Use the proper flux based on the base material type, shape, brazing type, and brazing method.
Procedures
(1) Braze the pipes as shown in the figure below at the temperature appropriate for the brazing material.
After brazing, keep supplying a flow of nitrogen gas until the pipes become cool enough to be touched by hand. (Be careful not to burn yourself.)
(2) Completely remove the flux after brazing.
(After brazing, keep supplying a
flow of nitrogen gas until the brazed
section is cooled down to 200ºC or
lower.)
Notes:
•
Keep the heated area to a minimum and braze the pipes at the appropriate temperature.
•
To prevent a fire, cover the pipes with a metal sheet and place a wet towel on the pipes.
•
After brazing pipes, do not splash water on the pipes to cool them down.
•
Avoid giving mechanical shock to the pipes until the brazed sections have solidified.
•
Make sure to check the components of the antioxidant before use. The components must not corrode the pipes if mixed with the refrigerant or refrigerant
oil.
Pipe size (D)
5 or more, less than 8
8 or more, less than 12
12 or more, less than 16
D
A
16 or more, less than 25
25 or more, less than 35
35 or more, less than 45
N
Brazed section
2
Cylinder
Stuff something in the pipe to keep air from enter-
ing the pipe.
Example of brazing pipes under nitrogen purge
Minimum insertion depth (B)
Gap (A–D)
6
0.05 to 0.35
7
8
0.05 to 0.45
10
12
0.05 to 0.55
14
Supply a flow of dry nitrogen gas at the rate
you slightly feel the flow (about 1 liter/minute).
(Unit: mm)
11
Advertisement
Chapters
Table of Contents
