Cla-Val 340-02/3640-02 - Manual (Page 19)

The CDHS-33 Is installed on Cla-Val 340 Series valves to main-
tain flow rate and allow the flow rate to be changed from a
remote location. It is also an effective solution for lowering costs
associated with "confined space" requirements by eliminating
the need for entry in valve structure for set-point adjustment.
Additional pilot controls, hydraulic and/or electronic, are also
available to perform multiple functions to fit exact system
requirements.
• Simplified Remote Valve Set-Point Control
• 12-24VDC Input Power
• Isolated Input
• Reverse Polarity Protection
• Reliable Hydraulic Operation
• IP-68 Submersible
The Cla-Val Model CDHS-33 Electronic Actuated Differential Pressure
Pilot Control provides remote set-point adjustment and accurate dif-
ferential pressure control for rate of flow control on Cla-Val 340 Series
Control Valves. Remote set-point command signals can be from any
SCADA-type control system using analog 4-20 mA signal or by con-
tact closure for cc/ccw rotation. A precision orifice plate installed with
valve creates differential pressure used for rate of flow control by the
CDHS-33. Operating on 12 to 24 VDC and consuming very little
power, it is an ideal control system for remote valve sites that may
even be solar powered. Existing manually-set Cla-Val 40 Series
Rate-of-Flow control valves can be retrofitted with CDHS-33 to add
remote set-point control. Verification of differential pressure and cor-
responding flow rate may be sent to SCADA system from customer
supplied differential pressure sensor attached to orifice plate.
The CDHS-33 consists of a hydraulic pilot and integral controller that
accepts a 4-20 mA remote set-point and positions the pilot to maintain
a maximum pressure differential at orifice plate and corresponding
flow rate within preset limits. Pressure differential settings are linear
between these settings. Special USB connector cable and free down-
loadable software can be used to change built-in electronic range lim-
its for differential pressure and corresponding flow rate. Continuous
internal monitoring of actuator position results in smooth transitions
between pilot set-points with no backlash or dithering. When power
or control input fail, the CDHS-33 pilot remains in automatic hydraulic
control assuring system stability under all conditions.
Electronic Actuated
Rate of Flow Pilot Control
CDHS-33
MODEL
Typical Applications