Cla-Val 350-02/3650-02 - Manual (Page 5)

Remote
Set-Point
SCADA
Computer
Remote Telemetry Unit
(Customer Supplied)
Optional
Process Variable
Transmitter of
Upstream Pressure
(Customer Supplied)
Upper
Zone
CLA-VAL
350 Series
Electronic Actuated
Pressure Sustaining Valve
with CRL-33 Pilot Control
Flow
CLA-VAL
CRL-33
Control
Lower Zone
• Simplified Remote Valve Set-Point Control
• 12 to 24 VDC Input Power
• Optically Isolated Input
• Reverse Polarity Protection
• Reliable Hydraulic Operation
• IP-68 (Submersible)
Schematic Diagram
Item Description
1 Hytrol (Main Valve)
2 X42N-2 Strainer & Needle Valve
3 CRL-33 Electronic Pressure Sustaining Control
Optional Features
Item Description
B CK2 (Isolation Valve)
D Check Valves with Isolation Valve
F Remote Pilot Sensing
H Drain to Atmosphere
S CV Flow Control (Opening)
Electronic Actuated
Pressure Sustaining Control Valve
F
D1
B1
2
S
B1 D2
D3
B2
3
1
INLET OUTLET
H
DRAIN TO
ATMOSPHERE
Remote Sensing
Typical Applications
The valve is designed to be used with supervisory control systems (SCADA),
having remote analog set-point output and process variable upstream pressure
input. It is also an effective solution for lowering costs associated with “confined
space” requirements by eliminating need for entry into valve structure for set-
point adjustment.
Additional pilot controls, hydraulic and/or electronic, can be easily added to per-
form multiple control functions to fit exact system requirements.
350-02
MODEL
(Full Internal Port)
3650-02
(Reduced Internal Port)
The Cla-Val Model 350-02/3650-02 Electronic Actuated Pressure
Sustaining Control Valve combines precise control of field proven Cla-Val
hydraulic pilots and simple, remote valve control. The Model 350-
02/3650-02 is a hydraulically operated, pilot controlled, modulating valve
designed to maintain constant upstream pressure within close limits. This
valve can be used for pressure sustaining, back pressure or unloading
functions in a by-pass system. The valve uses a CRL-33 pilot control,
consisting of a hydraulic pilot and integral controller, that accepts a remote
set-point command input and makes set-point adjustments to the pilot.
The recommended control method is simple remote set point change from
an RTU (Remote Telemetry Unit) to the CRL-33 where the 4-20 mA com-
mand signal is ranged to specific pressure range. Very accurate control
can be achieved when span does not exceed 100 psi. Since the CRL-33
is pre-ranged to the full spring range, some on-site calibration may be nec-
essary when this control method is used. Free downloadable software is
available from the Cla-Val website for this purpose. The CRL-33 can also
accommodate control systems where the RTU compares pressure trans-
mitter signal to the remote set point command signal. The RTU adjusts
the CRL-33 with 4-20 mA command signal containing an adequate dead-
band to prevent actuator dithering after the two signals agree.
Internal continuous electronic monitoring of actuator position results in vir-
tually instantaneous position change with no backlash or dithering when
control signal is changed. In the event of a power or control input failure,
the CRL-33 pilot remains in hydraulic control virtually assuring system sta-
bility under changing conditions. If check feature ("D") is added, and pres-
sure reversal occurs, the valve closes to prevent return flow.