IDM-based pneumatic outflow control

Robust, transparent, accurate, fast, low maintenance and reliable for wastewater, raw wastewater and rainwater.

Most exact discharge throttle for heavily polluted waste water

The MID flow measurement for full filling is the central element of the almost self-cleaning, remotely operated and highly precise pneumatic discharge control PNA. The reliable and never-tiring flap with pneumatic drive and the pinch valve react quickly to changing flow rates and conditions.

Flow limitation with control flap or pinch valve

The system is available in wet installation with a control flap or for dry installation with a pinch valve. The following figures show some positions of the pinch valve, which shows that the valve can open completely and unblock the entire cross section as well as close completely. In the intermediate positions it can be seen that the pipe crown remains open until shortly before it is completely closed, so that air can escape.Positionen Quetschventil The pinch valve was originally designed for the dosing of stones and gravel, which is why the integrated hard rubber sleeve is extremely robust and resistant to the processing of solids, gravel and aggressive media.

MID gesteuerte pneumatische Abflussregelung mit Quetschventil
Pneumatic discharge control used in storm water tanks

Technical information

ATEX Approval

  • Pinch valve: ATEX Zone I
  • Control flap: ATEX Zone I
  • Maintenance opening: ATEX Zone I
  • Piping: ATEX Zone I

Nominal width Design Control damper Direct drive

  • NW100 to NW500

Nominal width Design Control damper blade Shear drive

  • NW600 to NW1500

Nominal width Design Pinch valve

  • NW150 to NW400
  • The control flap is located immediately after the flow measurement, thus it reacts quickly to changes in discharge and can also maintain the programmed control value with the smallest deviation and delay time.
  • For the comparison with a knife gate valve flow control, the 1 to 10 rule of thumb can be used: While a knife gate valve can move to 100 individual positions in stages, the pneumatic discharge control system, thanks to the infinitely variable pressure control, can achieve at least 1000 individual positions – which is the basis for the high control accuracy.

The control of the pneumatic discharge control contains a touch display with zoom and swipe function, as well as a data logger and a local small DCS for use with a web browser, which can be accessed in the local network or, if desired, from the Internet. In addition to the versatile interfaces, the small DCS or the web server can also be integrated and displayed in the customer’s distributed control system.

Included as standard with modem for using all mobile networks up to 4G/LTE, Fixnet Internet connection and VPN technology

  • Signal outputs: 4-20 mA: instantaneous flow rate and set control value
  • Digital (active/passive): Flow counter and 2x fault
  • Signal inputs: 4-20 mA: set-point control value
  • Digital (potential-free): OPEN (remote); CLOSED (remote); AUTOMATIC; MANUAL START CLEANING;
  • Communication: RS485 (Modbus RTU/ASCII), RS232, Ethernet (Modbus TCP) connection via Internet/VPN.
  • VPN connection for remote maintenance with STEBATEC (Internet connection with STEBAmobile possible)

Connection diagram on request.


  • Control flap and pinch valve allow venting in the pipe crown, thus avoiding the formation of an air bubble in the controlled system, which would disturb the flow measurement
  • High-precision control with very short reset times and no running time limit
  • Pneumatic drive in wet ATEX environment better suited than e.g. electric drive
  • The throttle value is variably parameterizable/adjustable in the entire discharge spectrum
  • The control is remotely controllable and compatible with all commercial distributed control systems
  • Measures the flow with maximum 1% deviation from the measured value
  • Combined flow measurement and control system including calming sections with minimum space requirement
  • Detects contamination and discharges it selectively (flushing function, attachment discharge)
  • Throttle continues with an emergency program in case of power or device failure
  • Enables partial filling operation and prevents deposits
  • Is easy to maintain and can be dismantled/opened for cleaning without tools
  • Works with a standardized, mature control program
  • The devices can be set up dry or wet


Why pneumatic control flap or pinch valve instead of knife gate valve?

  • Air in the pipe crown can escape
  • Speed: Open to closed in 3 seconds
  • Accuracy: Membranes/bellows/cushions adjust very finely, while plate makes large movements in comparison
  • No emergency power generator necessary for emergency position in case of power failure, as the system continues to operate with residual pressure in the compressor
  • No wear of the spindle and sudden erratic behaviour
  • No electric drives in the hazardous area

References to this product

Let us advise you.

  • This field is for validation purposes and should be left unchanged.
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