14
EB 3135-1 EN
Design and principle of operation
2.3 Material numbers
2.3.1 Type 2488 Valve
The material designation can be found on
the cast body or you can contact us (the con-
figuration ID specification is needed) to find
out which material is used. For more details
on the nameplate, see section 2.1.
2.3.2 Electric actuator
Specifying the configuration ID, you can con
-
tact us to find out which material is used. See
associated actuator documentation for more
details on the nameplate.
3
Design and principle of oper
-
ation
Î
See Fig. 3
The pressure-independent control valve
(PICV) consists of the Type 2488 Valve and
an electric actuator. The valve is fitted with a
connecting piece for connection of an elec-
tric actuator. As a result, it is possible to
transmit the control signal of an electric con-
trol device to achieve additional temperature
control by changing the restriction position.
A maximum flow rate can be adjusted me
-
chanically at the restriction (orifice). The me
-
dium flows through the valve in the direction
indicated by the arrow on the valve body.
The flow rate is determined by the area re
-
leased by the restriction (8.5) and the plug
(3).
The installed set point spring (5) determines
the differential pressure across the restriction
of 0.2 bar. The pressure upstream of the re
-
striction (8.5) is transmitted over the control
line (7) to the upstream pressure side of the
actuator. The pressure downstream of the re-
striction acts on the low-pressure side of the
operating diaphragm (6.1) through a hole in
the valve plug. The differential pressure gen-
erated across the restriction is converted into
a positioning force by the operating dia-
phragm. This force is used to move the valve
plug depending on the force of the set point
spring (5). The flow rate is adjusted at the set
point adjuster (8.2).
