Caution
Warning
Piping
1. Preparation before piping
Before piping is connected, it should be thoroughly blown out
with air (flushing) or washed to remove chips, cutting oil and
other debris from inside the pipe.
2. Wrapping of pipe tape
When screwing piping or fittings
into ports, ensure that chips from
the pipe threads or sealing
material do not enter the piping.
Also, if pipe tape is used, leave 1
thread ridge exposed at the end
of the threads
.
3. Connection of fittings
1) For a fitting with sealant R or NPT, first, tighten it by hand,
then use a suitable wrench to tighten the hexagonal
portion of the body an additional two or three turns. For
the tightening torque, refer to the table below.
Connection thread size(R, NPT)
Proper tightening torque (N·m)
1/8
3 to
5
1/4
8 to 12
Follow the procedure of the manufacturer when fittings
other than SMC fittings are used.
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) For reuse
(1) Normally, fittings with a sealant can be reused up to 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, wind
sealing tape over the sealant before reusing. Do not
use any form of sealant other than the tape type of sealant.
(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.
4. Uni thread fittings
1) First, tighten the threaded portion by hand, then use a
suitable wrench to tighten the hexagonal portion of the
body further at wrench tightening angle shown below. For
the reference value for the tightening torque, refer to the
table below.
2) The gasket can be reused up to 6 to 10 times. It can be
replaced easily when it has sustained damage. A broken
gasket can be removed by holding it and then turning it in
the same direction as loosening the thread. If the gasket
is difficult to remove, cut it with nippers, etc. In such a
case, use caution not to scratch the seat face because
the seat face of the fitting’s 45° gasket is the sealing face.
Lubrication
1. Lubrication
1) The valve has been lubricated for life by the factory and
does not require any further lubrication.
2) If a lubricant is used in the system, use class 1 turbine oil
(no additives), ISO VG32. For details about lubricant
manufacturers’ brands, refer to the SMC website.
Additionally, please contact SMC for details about class 2
turbine oil (with additives) ISO VG32.
Once lubricant is utilized within the system, since the
original lubricant applied within the product during
manufacturing will be washed away, please continue to
supply lubrication to the system. Without continued
lubrication, malfunctions could occur.
If turbine oil is used, refer to the Safety Data Sheet (SDS)
of the oil.
2. Lubrication amount
If the lubrication amount is excessive, the oil may accumulate
inside the valve, causing malfunction or response delay.
So, do not apply a large amount of oil.
Connection Female Thread: Rc, NPT, NPTF
Uni thread size
Wrench tightening angle
after tightened by hand
(deg)
Tightening torque
(N·m)
1/8
30 to 60
3 to
5
1/4
30 to 60
8 to 12
Connection Female Thread: G
Uni thread size
Wrench tightening angle
after tightened by hand
(deg)
Tightening torque
(N·m)
1/8
30 to 45
3 to 4
1/4
15 to 30
4 to 5
VTA301 Series
3 Port Air Operated Valve / Precautions 2
Be sure to read before handling.
- 5 -
VT301
**
-OMH0007-B
