Model NDG-430 Mass Flow/Density Gauge

Density Measurement System
Model NDG-430 Mass Flow/Density Gauge
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The Density Sensor Set

The Density Sensor set comprises:
  • Source holder with tted gamma source
  • Gamma detector in housing
  • Pipe clamp assembly
  • UNIPROv Transmitter/Indicator
Source Holder Assembly
The source holder is a lead filled, steel fabrication designed to exceed the requirements of the South African Department of Health / Directorate Radiation Control. The isotope standardly used is Caesium137, which provides a good balance between measurement precision, longevity and cost. Other isotopes may be required for special applications.
Depending on the source holder model, the shutter mechanism may be either a Slide type or Rotary type. The standard shutter mechanism is a two position device – “ON (Measure)” & “OFF” (Closed). Alternative (optional) source holder models can be provided which feature either three- or four-position shutter mechanisms. These additional shutter positions provide Calibration References for simplied calibration/maintenance checks.
A single calibration point alone cannot reliably define the system calibration. At least two points are required. Our unique four-position shutter assembly provides for both a Zero reference and an on-scale Span calibration reference. Servo actuation of the source shutter is also possible to allow automated calibration checking.
The source holder may be equipped with our optional electronic Isotope Tag (I-Tag®) which removes the problems encountered in traditional stamped stainless steel tags which could become illegible or lost. The I-Tag® allows for a far safer & more reliable system of reading Radio Nuclide & Source Holder information. 

Gamma Detector Assembly (Model DSA-1)

The detector housing bolts to the Pipe Clamp. An optional safety shield is available, to signicantly reduce through radiation. The detector is scintillation type. Features of this detector are:

  • Factory sealed detector (No access required) - Termination via external junction box
  • Greater sensitivity
  • Lower isotope activity.
  • Lower radiation levels – greater margins of safety.
  • Auto (electronic) shut down under empty pipe conditions (to protect the detector from over radiation damage).
  • High noise immunity, RS-485 type output.
Pipe Clamp Assembly
The pipe clamp bolts around the process pipe and provides attachment points for the Density Detector Assembly and Source Holder. The clamps and the mounting bolts are from stainless steel.
The UNIPROv may be located at any convenient location for termination/indication, and may be up to 300m from the Detector. Standardly the UNIPROv is supplied “Blind” using the PTU for Calibration/Maintenance. Optionally UNIPROv may be equipped with a local keypad & display.

Mass Flow Option:

When connected to a volumetric type, wet ow rate meter, the Model 430 can provide Mass Flow computation capability and output. Discrete outputs available are:

  • Density (4-20mA)
  • Dry Mass Flow rate (4-20 mA)
  • Volumetric Wet ow rate (4-20 mA)
  • Totalised dry mass
  • Totalised Wet Flow