7 VG9H 70 en
11
3.5
Piping
Table 3 provides the recommended tube sizes in accord-
ance with actuator sizes. Tube sizes are the minimum values
allowed. For supply air choose a tube one size bigger. Sup-
ply air and actuator conduit sizes can be seen also in
figure 9 below.
Connect the air supply to S. Connect C1 and C2 to the actua-
tor, see Fig. 10. C1 must be plugged if single-acting actuator.
Liquid sealants, such as Loctite 577 are recommended for
the pipe threads.
The air supply must be clean, dry and oil-free instrument air,
see Section 1.5.
CAUTION:
Do not exceed the permitted supply pressure of the
ValvGuard!
CAUTION:
The stroking times mentioned in Table 3 are trendset-
ting. They are measured with 5 bar supply air pressure
with actuator only and without a valve. They may vary
significantly due to different factors such as, but not
limited to, pressure difference of the valve, the stiction
of the actuator, supply air pressure, the capacity of the
supply air system and the dimensions of the supply air
pipeline.
NOTE:
When opening/closing times are defined in the Table 3,
the specified spool valve size can be used with that actua-
tor size. If there is '-' sign in the table or if smaller actuators
than shown in the table are used, please contact Metso.
NOTE:
When faster speeds are needed than shown in the table,
QEV or volume booster can be used. Bypass valve is man-
datory with volume boosters and QEV. Contact Metso for
separate instrumentation diagrams and instructions.
NOTE:
When QEV or volume booster is used, VG with standard
spool valve (VG9_15_) is required.
NOTE:
When VG9000H_P type is used the actuator piping is
reversed! C2 must be plugged if single-acting actuator.
NOTE:
An excess of sealant may result in faulty operation of the
controller.
Sealing tape is not recommended.
Do not exceed torque of 30 Nm/22 lbf ft when fitting
1/4" NPT connectors to C1, C2 and S (VG921_).
Ensure that the air piping is clean.
NOTE:
A ValvGuard mounted on a spring actuator must be con-
nected only as single-acting. See Fig. 10.
CAUTION:
The air supply system must be of sufficient size and
capacity to ensure that at maximum flow during valve
movement the pressure at the ValvGuard must not fall
below 3 bar. Also note that if the air supply system
allows the pressure at the ValvGuard to fall below the
actuator minimum supply pressure during valve
movement the stroke speed will be affected
Table 2
Spring rates
Actuator type
Spring rate (bar/psi)
B1JK
3 / 43
B1J
4.2 / 61
B1JV
5.5 / 80
QPX_A
1.4 / 20
QPX_B
2.8 / 41
QPX_C
4.1 / 60
QPX_D
5.5 / 80
Adjust regulator pressure to a level that is max 1 bar (14.5 psi)
+ spring rate.
Fig. 9
Air supply and actuator conduits
C2
S
C1
VG921_
1/4” NPT
C2
S
C1
VG9235_
1/2” NPT
VG9237_
C2
S
1” NPT
1/2” NPT
