Multi-channel water analyzer

Unlike centrifuge, distillation and Carl Fisher methods that do single point measurement at a time, a multi-channel scanning water analyzer (MCSWA) is a highly integrated apparatus for measuring water distribution, surface/interfacial levels and thicknesses of a multiphase dispersion continuously. The scanned curves provide water profiles and surface/interfacial information as a function of vertical position in respective testing samples. MCSWA is a proprietary technology developed by M & T Instruments Ltd. and is in patent pending status.

Working principle of the instrument

Fig. 1 is a schematic circuit of a data acquisition unit or printed circuit board (PCB) for a 4-channel scanning water analyzer. The data acquisition unit comprises 4 LC-tanks for connecting 4 capacitive sensors (Cs1, through Cs4), a high-precision frequency counter and a USB microcontroller.

Fig. 1 Schematic circuit of a 4-channel scanning water analyzer.

Each LC tank has an inductor and a capacitor connected in parallel to form a resonance circuit. Its resonance frequency (F) can be expressed as

where L is the inductance of the inductor, Cs is the capacitance of a variable capacitor, which is actually the capacitive sensor. The resonance frequency is measured using a high-precision analog-to-digital frequency converter or counter. The measured frequency is then read by the USB microcontroller. The capacitance of a sensor (Cs ) can be calculated using

and its derivative as a function of bottle mark (x or sample volume) is

Fig. 2 is a schematic illustration of the 4-channel scanning water analyzer. It comprises a support station, a motorized vertical linear stage, a heating system having a heating cell control box and 4 heating cells, a sensor holder manifold holding 4 sensors, a data acquisition unit (or PCB) communicating between the sensors and a computer, a motorized front enclosure to close/open for loading samples and positioning sensors and a rear enclosure for electrical maintenance. The sensors can be well controlled to move down precisely to dip the sensors into the samples held in the 4 respective sample bottles, which are kept in the 4 heating cells maintaining a desired temperature. Four frequency curves and four capacitance curves are continuously acquired in a scan. Water distribution, surface/interfacial levels and thicknesses are derived via post-data processing. Both the scanning control and post-data processing are integrated into a user-friendly program using LabVIEW graphic interface.  Fig. 3 is a photo of the 4-channel scanning water analyzer.

Fig. 2 Schematic illustration of the 4-channel scanning water analyzer.
Fig. 3 A 4-Channel Scanning Water Analyzer with (right) and without (left) Enclosure.

Features

  1. Simultaneously measure water distribution, interfacial levels and thicknesses,
  2. High-resolution water profile analysis, 0.1% by volume,
  3. Multiple sample scans and multiple phase scans simultaneously,
  4. Integrated program for scanning, data acquisition and post-data processing,
  5. No calibration is required for water content ranking for various chemical screening tests,
  6. Aqueous phase qualitative analysis,
  7. Scanned graphs and data can be exported to a clipboard, excel file and PDF file,
  8. Saved data can be reloaded for post-data processing,
  9. The heating cells can be operated up to 150 ℃ when sample bottles are capped, which can be used for sample conditioning to allow phase separation prior to scanning,
  10. Multiple channels (4 or 8) selectable,
  11. Suitable for both water-in-oil emulsion and oil-in-water emulsion systems

Specifications

  • Name: 4-Channel scanning water analyzer
  • Model: MCSWA-4-1000-1
  • № of Channels: 4
  • Water content resolution: 0.1% by volume
  • Surface/interface level resolution: 0.1 mm
  • Vertical stage velocity: ≤ 5 mm/s
  • Vertical stage travel distance: 200 mm
  • Scanning velocity: 0.100 – 0.125 mm/s
  • Power supply for vertical stage motor: 24 V DC,
  • Communication for vertical stage’s motor: USB to RS422
  • Heating cell diameter: 63.5 mm for 200 ml glass bottles, 56.7 mm for 100 ml glass bottles
  • Heating cell operating temperature: ≤ 95 ± 0.1℃, limited by water boiling point
  • Power supply for heating cells: 85 – 240 V AC
  • Front enclosure: Manual or motorized
  • Dimension: W423 mm × D533 mm × H600 mm
  • Computer included
    • Operating system: Win 10
    • CPU: ≥ 1.5GHz
    • Memory: ≥ 8GB
    • Hard disk: ≥ 500G
    • № of USB 2.0 and/or 3.0 port: 3
    • HDMI: 1