Instruction No EF 5000 E
01/2004
4
The concept of the Camflex® II valve is based on an
eccentrically rotating spherical plug contained in a
free flow design ANSI Class 600 body. The plug
seating surface is joined by flexible arms to a hub
which slides onto a rotating shaft. The plug is free to
center itself along the axis of the shaft. A positive
seal between plug and seat is achieved by elastic
deformation of the plug arms. The chamfered seat
ring is fixed in the valve body by a threaded retainer.
The plug and shaft are rotated through an angle of
50° by a lever linked to a powerful spring-opposed
rolling diaphragm actuator.
The solid disk-type handwheel and locking lever,
provided as standard features on the Camflex® II
valve and are mounted on the yoke opposite the
actuator. The handwheel may be used as a manual
actuator or as a limit stop. A threaded hole in the
opposite side of the yoke accommodates a cap
screw and locknut which may be inserted as a limit
stop in the other direction, or in combination with the
handwheel to lock the valve in a selected position.
The handwheel on Camflex® II is designed to be
used for emergency action only.
The actuator is generally mounted with air-loading to
counter the dynamic torque on the plug. In figure 2
the flow direction tends to open the plug and the
actuator is oriented to close it with increasing air
pressure. The actuator spring force assists plug off-
balance forces to open the valve on air failure. If the
valve is to close on air failure, the body would be
turned around in the line so that flow tends to close
the plug and the actuator position would be reversed.
The Camflex® II valve has a modified linear flow
characteristic, which is the same in either flow
direction. It can be easily transformed to an equal
percentage when equipping the valve with a
positioner 4700 series, 8000 series, SVI (Smart
Valve Interface) or FVP.Reduced TRIM factors 0.4
and 0.6 are available on all sizes. The flow capacity
of a 0.4 factor is 40% of the nominal capacity of the
valve and it is 60% for the 0.6 factor. Factors 0.1 and
0.2 are available on the DN 25 (1") valve.
The ability of the Camflex® II valve to handle a wide
range of process fluid temperatures is due to the
long integrally cast bonnet. This affords ample
radiation surface to normalise the packing
temperature. Therefore, with self-lubricating TFE
Aramid fiber packing, the valve handles
temperatures from - 200°C to + 400°C (-320°F to
+750°F). When insulating the valve, do not insulate
the body neck (see figure 3).
3. Principle of operation
Seat Ring
Fluid flow
Plug
Guide Bushing
Flexible arms
Guide Bushing
Shaft
Air
Actuator
Lever
Handwheel
Figure 2
Figure 3
