AirSep AS-Q, Instruction Manual

Page: 129 / 198

AS-Q—AS-Z Series Instruction Manual 129
AirSep Corporation
1. GENERAL
1.1 Scope of the Manual
This instruction manual contains important information
regarding the installation, operation and maintenance of
the Jamesbury® Model C Wafer-Sphere Butterfly Valves.
Please read these instructions carefully and save them for
future reference.
WARNING:
AS THE USE OF THE VALVE IS APPLICATION SPECIFIC, A NUMBER
OF FACTORS SHOULD BE TAKEN INTO ACCOUNT WHEN SELECTING
A VALVE FOR A GIVEN APPLICATION. THEREFORE, SOME OF THE
SITUATIONS IN WHICH THE VALVES ARE USED ARE OUTSIDE THE
SCOPE OF THIS MANUAL.
IF YOU HAVE ANY QUESTIONS CONCERNING THE USE, APPLICATION
OR COMPATIBILITY OF THE VALVE WITH THE INTENDED SERVICE,
CONTACT METSO FOR MORE INFORMATION.
1.2 Offset Shaft Design
One of the design features of the Wafer-Sphere valve that
is responsible for its superior performance is the valve’s
offset shaft design. The shaft is offset in two planes: (1)
away from the valve disc centerline and (2) behind the disc
sealing plane (See Figure 1). Offset shaft design makes the
rotating disc “cam” back and away from the seat, completely
eliminating the usual wear points at the top and bottom of
the seat. Because the disc rotates off the seat in an eccentric
arc, it operates in one quadrant only (See Figure 1).
WARNING:
IF THE VALVE DOES NOT HAVE EITHER A HANDLE ON AN ACTUATOR
DO NOT PRESSURIZE. UNRESTRAINED DISC MAY OPEN OR CLOSE
DUE TO PIPELINE PRESSURE.
1.3 Positive Stop Feature
To prevent seat damage from over-travel of the disc
beyond the closed position (usually during field mounting
of a handle or actuator), a “positive stop” feature has
been designed into the Wafer-Sphere butterfly valve. The
“positive stop” feature also makes it possible to adjust the
actuator travel stops in-line. The location of this feature is
shown in (Figure 1).
1.4 Actuation
High line pressure may create high enough forces to pull a
manual handle out of an operator’s hand. With Types 815W,
815L, 830W, and 830L valves, either a manual gear operator,
a pneumatic or an electric actuator should be used in place
of a detent handle when the differential pressure exceeds
those listed in (Table 1).
TABLE 1
Valve Size
Maximum Allowable Differential
Pressure for Use
With a Detent Handle
3” & 4”
(DN 80 & 100)
300 psi
(20.7 bar)
5”, 6” & 8”
(DN 125, 150 & 200)
105 psi
(10.35 bar)
10” & 12”
(DN 250 & 300)
50 psi
(3.45 bar)
1.5 Wafer Body Design
Some wafer designs (See Figure 2) contain flange bolt
holes or slots in the body to hold the valve and assist
with correct alignment during installation in the line. The
centering holes or slots in wafer bodies alone are not
suitable, or intended for containing line pressure, and are
only for use in conjunction with a fully bolted pipeline
flange.
1.6 Snap-in Inserts
Snap-in inserts on wafer style valves must be clamped
before cycling the valve when out of the pipeline. Use
soft-faced clamps across the body to avoid damaging the
gasket surface. Damage to body seals can result if snap-in
inserts are not clamped when valve is cycled.
Offset Shaft Operatio
n
Figure 1
Positive Stop
HANDLE DIRECTION
VALVE OPEN
HANDLE
DIRECTION
VALVE
CLOSED
Open Always
Counterclockwise
Close Always
Clockwise
IMO 1/18
IMO-308 EN 3