SMC Networks KFG2 Series Operation Manual page 8

2. Specific Product Precautions (4)
Maintenance
Warning
(1) Perform maintenance inspections according to
the procedures indicated in the operation
manual.
If handled improperly, malfunction and damage of
machinery of equipment may occur.
(2) Maintenance work
If handled improperly, compressed air can be
dangerous. The assembly, handling, repair, and
element replacement of pneumatic systems
should be performed by a knowledgeable and
experienced person.
(3) Drain flushing
Remove drainage from air filters regularly.
(4) Removal of equipment and supply/exhaust of
compressed air
When components are removed, first confirm that
measures are in place to prevent workpieces from
dropping, run-away equipment, etc. Then, cut off
the supply pressure and electric power, and
exhaust all compressed air from the system using
the residual pressure release function.
When the equipment is restarted, proceed with
caution after confirming that appropriate measures
are in place to prevent cylinders from sudden
movement.
Caution
(1) Be certain to wear safety glasses at all times
during periodical inspections.
(2) During regular maintenance, check for the
following and replace any components as
necessary.
a) Scratches, gouges, abrasion, corrosion
b) Leakage
c) Flattening or distortion of tubing
d) Hardening, deterioration or softness of tubing
e) Loosening of the union nut
(3) Do not repair the fittings or patch the
tubing for reuse.
(4) After operation at a high temperature,
leakage may occur due to time dependent
change of the tube material. If leakage
occurs, remove the tube, cut off the
connecting part of the tube, and connect to
the piping again.
Check if the tube dimension accuracy is within
the recommended tolerance. If it is difficult to
take the tube out of the body, bend the tube to
the side to remove.
Connection Thread Tightening Method
Caution
(1) Fittings with sealant: R, NPT
1) First, tighten the fitting by hand, then use a
wrench appropriate for the hexagon flats of the
body to tighten it a further two or three turns.
For a tightening torque guide, see the table
below.
If the fitting is tightened with excessive torque,
the fitting may break. In particular, for the
swivel elbow, the stud may come off.
Connection thread size
NPT, R1/8
NPT, R1/4
NPT, R3/8
NPT, R1/2
2) If the fitting is tightened with excessive torque,
a large amount of sealant will seep out.
Remove the excess sealant.
3) Insufficient tightening may cause seal failure,
or loosen the threads.
4) Reuse
1. Normally, fittings with a sealant can be
reused 2 to 3 times.
2. To prevent air leakage through the sealant,
remove any loose sealant stuck to the fitting
by blowing air over the threaded portion.
3. If the sealant no longer provides effective
sealing, wrap sealing tape over the sealant
before reusing. Do not use the sealant in any
form other than a tape type.
4. Once the fitting has been tightened, backing
it out to its original position often causes the
sealant to become defective. Air leakage will
occur.
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Tube
Body
Tightening torque [N・m]
3 to 5
8 to 12
15 to 20
20 to 25