Flowserve Valtek Valdisk Control Valves - Manual (Page 2)

10-2
WARNING: Keep hands, hair, clothing, etc. away from
the rotating disc and the seat when operating the valve.
Failure to do so could cause serious injury.
CAUTION: Because of Valdiskís self-centering seat,
there is no reason to open the valve at any time during
installation. Therefore, the valve should remain closed
until the valve is fully installed.
4. Connect air supply and instrument signal. Throttling valves
are usually equipped with valve positioners. Two connec-
tions are marked for the air supply and for the instrument
signal. Both cylinder and positioner are suitable for 150
psi air supply. An air regulator is not required unless the
supply pressure exceeds 150 psi. An air filter is recom-
mended unless the supply air is unusually clean and dry.
All connections must be free of leaks.
CAUTION: On valves equipped with air filters, the air
filter bowl must point down; otherwise, the air filter will
not perform properly.
NOTE:
5. Make sure proper clearance exists internally in the mating
piping to permit proper disc rotation.
6. Apply recommended torque values to line flange bolting
for proper sealing (see Table 1).
Quick-check
Prior to start-up, check the control valve by following these
steps:
1. Check for full stroke by making the appropriate in-strument
signal change. Observe disc position indicator plate
mounted on the transfer case. The disc should change
position in a smooth, rotary fashion.
2. Check all air connections for leaks. Tighten or replace any
leaky lines.
3. Evenly tighten the packing nuts to slightly over finger-
tight.
CAUTION: Do not overtighten packing. This can cause
excessive packing wear and high shaft friction, which
may impede shaft rotation.
After the valve has been in operation for a short time,
check the packing nuts to make sure they are just over
finger-tight (readjust if necessary). If packing box leak-
ing occurs, tighten the packing nuts only enough to stop
leakage.
4. To observe the valve failure mode in case of air failure,
position the valve to mid-stroke and shut off the air supply
or disconnect the instrument signal. By observing the
indicator plate, the disc should either fail open or closed.
If incorrect, refer to the ìReversing the Actuatorî section
in the appropriate Actuator Maintenance Instructions.
Table 1: Flange Bolting Torques
Valve Size
(Inches)
Rating
Torque
Carbon Steel
(ft-lbs)
Torque
Stainless Steel
(ft-lbs)
2
150
300
600 118
118
118 74
74
74
3
150
300
600 118
209
209 74
131
131
4
150
300
600 118
209
337 74
131
211
6
150
300
600 209
209
505 131
131
316
8
150
300
600 209
337
728 131
211
455
10
150
300 337
505 211
316
12
150
300 337
728 211
455
14 150 505 316
16 150 505 316
18 150 728 455
20 150 728 455
24 150 1009 631
30 150 1009 631
*Note: All values are + or - 10%
Installation
1. Before installing the valve, clean the line of dirt, scale,
welding chips, and other foreign material. Clean the gasket
surfaces thoroughly to insure leak-proof joints.
2. Check flow direction to be sure valve is installed correctly.
Fail-closed valves should be installed with the shaft up-
stream only on gas service. It is preferred that liquid
service valves must be installed with the shaft downstream
regardless of air failure action. However, under certain
flow conditions the valve can flow shaft upstream. Con-
sult factory if the valve must be mounted with the shaft
upstream in liquid service. Fail-open valves should be
installed with the shaft downstream.
WARNING: When installing the valve in-line between
flanges, make certain the flange face gasket covers
both seat retainer and body and surface. Failure to do
so will cause excessive leakage downstream. Refer to
ìSeat Insert/Snap-ring Configurationî in Figure 1.
3. Fully close the valve before and during the installation
process.