High Wall, Heat Pump Type
Service Manual
21
Toshiba
Brazing method to prevent oxidation
1) Attach a reducing valve and a flow-meter to the
Nitrogen gas cylinder.
2) Use a copper pipe to direct the piping material,
and attach a flow-meter to the cylinder.
3) Apply a seal onto the clearance between the
piping material and inserted copper pipe for
Nitrogen in order to prevent backflow of the
Nitrogen gas.
4) When the Nitrogen gas is flowing, be sure to
keep the piping end open.
5) Adjust the flow rate of Nitrogen gas so that it is
lower than 0.05 m
3
/Hr or 0.02 MPa (0.2kgf/cm
2
)
by means of the reducing valve.
6) After performing the steps above, keep the
Nitrogen gas flowing until the pipe cools down
to a certain extent (temperature at which pipes
are touchable with hands).
7) Remove the flux completely after brazing.
Fig. 2-5-1
Prevention of oxidation during brazing
Nitrogen gas
cylinder
Pipe
Flow meter
M
Stop valve
From Nitrogen cylinder
Nitrogen
gas
Rubber plug
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