oventrop Cocon QTR Instrucciones De Instalación Y Operación Para El Instalador Especializado página 3

Illus. 3 Example settings
When mounting an actuator, the corresponding installation in-
structions must be observed
The flow-meter "OV-DMC 2" can be connected to the pressu-
re test points. This will determine if the valve is working within
the control range. The pump setting can be optimised by
measuring the differential pressure.
For this purpose, the pump head is reduced until the hydrau-
lically underprivileged valves are just working within the con-
trol range.
Illus. 4 Differential pressure
With a flow-meter connected (e.g. OV-DMC2) the differential
pressure is measured across the valve.
The illustrated section of the "Cocon QTR" valve (illus. 5) sho-
ws three pressure ranges. "p1" is the inlet and "p3" the outlet
pressure of the valve. "p2" is the working pressure actuating
the diaphragm unit.
The differential pressure "p1" - "p2" is maintained at a constant
level by the integrated diaphragm unit (pos. 1a) of the combi-
ned control and regulating valve.
Handwheel
7 GPM+ 0 GPM = 7 GPM
Locking clip in
open position
7 GPM+ 3.5 GPM = 10.5 GPM
Locking clip in
open position
Legend:
1 Flow control unit
1a Diaphragm unit
1b Nominal value unit
2 Regulating unit
3 Handwheel
4 Diaphragm
5 Regulating sleeve
6 Setting sleeve
Illus. 5 Construction of the "Cocon QTR" valve
Illus. 6 Function principle of the "Cocon QTR" valve
The integrated diaphragm unit (pos. 1a) maintains the differen-
tial pressure "p1" - "p2" at a constant level not only across the
regulating unit (pos. 2) activated by the actuator but also
across the nominal value unit which can be set to a maximum
flow value (pos. 1b).
Even were high differential pressure variations "p1" - "p3" oc-
cur, e.g. if sections of the system are activated or inactivated,
the differential pressure "p1" - "p2" is kept at a constant level.
This way, the valve authority of the "Cocon QTR" valves amo-
unts to (a=1). Even during low demand periods with steady
control (e.g. in conjunction with 0-10 V actuators), the valve
authority within the effective valve lift amounts to 100% (a=1).
2.9
Differential pressure p1 - p 3 [psi]
Illus. 7 Flow characteristic line for different presetting
The minimum required differential pressure "p1" - "p3" across
the valve can be obtained from the below chart. As for valves
with integrated flow control, the required minimum differential
pressure changes depending on the nominal setting. The
mathematical interrelationship is considered in the chart.
Lift position of Position of
58 the regulating the
valve handwheel
3