Electronic Actuated Rate of Flow ControlValve with Manual Hydraulic Bypass

Product Advantages

  • Simplified Remote Valve Set-Point Control
  • Ideal for use with VC-22D Electronic Valve Controller
  • 12 to 24 VDC Input Power
  • Easy Interfacing to SCADA Systems
  • Accurate Flow Control
  • Reliable Hydraulic Operation
  • Submersible IP-68

The Cla-Val Model 340-07 Electronic Actuated Rate of Flow Control Valve with Manual Hydraulic Bypass combines the precise control of field proven Cla-Val hydraulic pilots and simple remote valve control. The Model 340-07 valve controls flow by limiting flow to a preselected maximum rate (within a fourto one ratio),regardless of changing line pressure. It is a hydraulically operated, pilot controlled, diaphragm actuated control valve. The valve uses a CDHS-34 actuated pilot control, consisting of a hydraulic pilot and integral controller that accepts a remote set-point command input and makes smooth set-point adjustments to the pilot.

The recommended control method is simple remote set point change from an RTU (Remote Telemetry Unit) to the CDHS-34 where the 4-20 mA command signal is ranged to specific flow range of orifice plate and hydraulic pilot control components. Very accurate control can be achieved when span does not exceed 4:1 turndown. Since the CDHS-34 is pre-ranged to full spring range, some on-site calibration may be necessary when this control method is used. Free downloadable software is available from the Cla-Val website for this purpose. The CDHS-34 can also accommodate control systems where the RTU compares flow rate transmitter signal to the remote set point command signal. The RTU adjusts the CDHS-34 with 4-20 mA command signal containing an adequate deadband to prevent actuator dithering after the two signals agree.

Internal continuous electronic monitoring of actuator position results in virtually instantaneous position change with no backlash or dithering when control signal is changed. In the event of a power or control input failure, the CDHS-34 pilot remains in hydraulic control virtually assuring system stability under changing conditions. If check feature (“D”) is added, and pressure reversal occurs, the valve closes to prevent return flow. During SCADA startup and maintenance the manually-adjusted CDHS-18 pilot control allows automatic hydraulic valve operation when no electric power is available for CDHS-34.

Schematic Diagram
Item Description
1.  Hytrol Main Valve 100-01
2.  X58C Restriction Fitting
3.  CDHS-34 Electronic Differential Control
4.  CDHS-18 Differential Control
5.  CK2 Isolation Valve
6.  X52D-1 Orifice Plate Assembly

Optional Features
Item Description
A.  X46A Flow Clean Strainer
B.  CK2 Isolation Valve
C.  CV Flow Control (Closing)
D.  Check Valves with Isolation Valve
P.  X141 Pressure Gauge
S.  CV Flow Control (Opening)
V.  X101 Valve Position Indicator
Y.  X43 “Y” Strainer

Typical Application

The valve is designed to be used with supervisor control systems (SCADA), having an isolated remote analog set point output and a process variable flow transmitter input. It is also an effective solution for lowering costs associated with “confined space” requirements by eliminating the need for entry into valve structure for set-point adjustments and system information. Additional pilot controls, hydraulic and/or electronic, can be easily added to perform multiple control functions to fit exact system requirements.

Model 340-07 (Uses Main Valve Model 100-01)

Pressure Ratings (Recommended Maximum Pressure – psi)


Model 340-07 Dimensions (inches)

Model 340-07 Metric Dimensions (Uses Main Valve Model 100-01)

Model 100-01 Full Port Hytrol Main Valve

CDHS-34 Overview

The CDHS-34 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 downloadable software can be used to change built-in electronic range limits for differential pressure and corresponding flow rate. Internal setting
can also be changed through Modbus. 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-34 pilot remains in automatic hydraulic control, assuring system stability under all conditions.

CDHS-34 Overview

Adjustment Range
30 to 480 inches H2O Differential (750 mm – 12000mm)
4 : 1 Turndown flow ratio
Specify min/max flow rate or orifice bore size (see E-X52E)

End Connection
3/8″ NPT

Temperature Range
Water: to 180° F / 82° C

Pilot Control: Low Lead Bronze
Trim: Stainless Steel Type 303
Rubber:Buna-N® Synthetic Rubber

Available with optional Stainless Steel or Monel
materials. Consult factory for details
Note: Available with Remote Sensing for orifice upstream,
specify CDHS-34A

CDHS-34 Actuator Specifications

Supply Power Input:
12V to 24V DC
No Load draw: 50 mA
Max. Load draw: 250 mA

Remote Command Inputs:
• 4-20mA, analog signal (isolated and reverse-polarity protected)
• Dry contact closure (CW/CCW) Position Feedback Signal: 4-20 mA

Alarm Output:
Dry-contact closure (High/Low)

Speed of Rotation:
Adjustable On/Off time, max 6 rpm

LED Indicator

Loss of Power:
Actuator will remain in last commanded position.

Loss of Signal Position:
Programmable – 4 mA, Last, or 20 mA

Electrical Connections:
Single, 30 feet of permanently attached cable with color-coded power supply and signal wires

Mechanical Specifications:
Protection Class: IP-68 (Temporary submersible)
Ambient Temperature: 15° to 150° F (-10° to 65° C)

Electronics Enclosure: Anodized Aluminum
Mechanical Housing: Bronze
Coupling Assembly: Stainless Steel
Gear Train: Stainless Steel, permanently lubricated