De-Aired Water Supply System - QualiGTX™ DWS 30

De-Aired Water Supply System - QualiGTX™ DWS 30

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De-Aired Water Supply System - QualiGTX™ DWS 30
  • De-Aired Water Supply System - QualiGTX™ DWS 30
De-Aired Water Supply System - QualiGTX™ DWS 30
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De-Aired Water Supply System - QualiGTX™ DWS 30

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De-Aired Water Supply System – QualiGTX™ DWS 30

The QualiGTX™ DWS 30 De-Aired Water Supply System conditions laboratory water for geosynthetic testing by removing dissolved gases and maintaining a controlled temperature. Designed for permeability, permittivity, and in-plane flow measurements, the system processes a 30-liter water supply, removes dissolved oxygen and carbon dioxide through heating, and regulates the water temperature before delivering it to the testing equipment. Hose connections allow direct supply to permeameters, transmissivity testing systems, and other compatible apparatus. This centralized arrangement eliminates the need for laboratories to prepare individual water batches manually and provides a consistent source for repeated testing.

De-airing and temperature regulation take place within a single cabinet. An electrically powered heater and compressor-based refrigeration system operate through digital PID control, maintaining reservoir temperatures between 15°C and 105°C. This range allows the water to be heated to boiling for gas removal and subsequently cooled to the temperature specified by the test method. An adjustable 100 W pump circulates water within the reservoir or transfers it to external equipment. The system can also provide heating or cooling circulation for separate laboratory vessels.

Water quality and temperature stability directly affect the reliability of hydraulic test measurements. When dissolved gases escape from water inside a specimen, the resulting bubbles can obstruct pores and flow channels, causing artificially low flow measurements. Temperature fluctuations introduce another source of variation by changing water viscosity and increasing the need for measurement corrections. The QualiGTX™ DWS 30 controls both variables before water enters the testing apparatus, helping laboratories reduce preparation time and maintain consistent results across different operators and shifts. Its floor-standing design allows convenient placement beside the testing bench, with the capacity to supply multiple instruments as required.

De-Aired Water Supply System – QualiGTX™ DWS 30 Applications

The QualiGTX™ DWS 30 supports laboratory procedures that require a dependable supply of degassed water maintained at a specified temperature. Its applications include:

  • Geotextile Permeability and Permittivity Testing: Delivers de-aired water to constant-head and falling-head permeameters, preventing entrapped bubbles from interfering with water movement through geotextile structures.

  • In-Plane Flow and Transmissivity Testing: Supplies conditioned water to geocomposite drainage and geonet testing systems for evaluating flow capacity under confining pressure between plates.

  • Drain Discharge Capacity Testing: Maintains a consistent water supply for extended flow measurements involving prefabricated vertical drains and drainage geocomposites.

  • Geomembrane and Geosynthetic Clay Liner Hydraulic Testing: Provides temperature-controlled, degassed water for hydrostatic pressure and impermeability testing equipment.

  • Soil Mechanics and Geotechnical Laboratories: Supports triaxial back-pressure saturation and soil permeability procedures, where residual air can affect specimen saturation and volume-change measurements.

  • Geosynthetics Manufacturing Quality Control: Provides production laboratories with a consistent water supply for routine testing and batch-release evaluations.

  • University and Research Laboratories: Functions as a circulating constant-temperature bath for additional experimental setups through its external circulation connection.

  • Independent Testing and Certification Laboratories: Establishes consistent water preparation conditions across multiple hydraulic testing stations, supporting standardized laboratory procedures.

De-Aired Water Supply System – QualiGTX™ DWS 30 Key Features

The QualiGTX™ DWS 30 integrates water degassing, temperature regulation, and circulation capabilities into one floor-standing laboratory system.

  • Thermal De-Airing of the Full 30 L Charge: Heats the entire reservoir to release dissolved oxygen and carbon dioxide, providing a sufficient volume of conditioned water for a full day of laboratory testing.

  • 15°C to 105°C Temperature Range: Accommodates both boiling-based de-airing and controlled cooling for test procedures that require specific water temperatures.

  • Compressor-Based Refrigeration: Rapidly reduces water temperature following the de-airing process through an environmentally rated refrigerant circuit.

  • Multi-Layer Circuit Protection: Incorporates overheat and overcurrent protection to safeguard the compressor during extended operation, including long unattended runs.

  • Self-Tuning PID Control: Allows operators to enter PID parameters manually or use automatic tuning, helping maintain the selected temperature without repeated adjustments.

  • 0.1°C Calibration Offset: Enables temperature display correction against a reference thermometer, maintaining alignment with the laboratory's traceable measurement instruments.

  • Dual Circulation Modes: Provides internal circulation to distribute temperature evenly throughout the reservoir and external circulation to deliver conditioned water to connected testing equipment.

  • Adjustable-Flow 100 W Pump: Allows water delivery to be adjusted according to equipment requirements, accommodating low-flow permeameter applications and higher-volume transmissivity testing.

  • External Heating and Cooling Capability: Circulates water through separate laboratory vessels to raise or lower their temperature, extending the system's usefulness beyond hydraulic testing.

  • Digital Operator Interface: Combines temperature monitoring and setpoint adjustment on a single control panel for straightforward daily operation.

  • Hose-Connected Output: Uses hose fittings to connect directly to geosynthetics testing equipment without requiring permanent plumbing installations.

Theory and Method

The removal of dissolved gases from water is based on Henry's law, which describes the relationship between gas solubility and the partial pressure of the gas above the liquid. Water can retain different amounts of oxygen, nitrogen, and carbon dioxide depending on their respective partial pressures. Gas solubility decreases substantially as water temperature increases. At room temperature, ordinary tap water typically contains approximately 9 mg of dissolved oxygen per liter, together with a greater quantity of dissolved nitrogen. Heating the water toward its boiling point reduces gas solubility to nearly zero, allowing the released gases to escape through the water's exposed surface.

This process is particularly important in hydraulic testing because dissolved gases can interfere with flow measurements inside geosynthetic specimens. As water passes through a geotextile or drainage core under decreasing pressure, previously dissolved gases can separate from the liquid and form fine bubbles. These bubbles collect within pore openings and along internal channel surfaces, reducing the area available for water flow. The resulting restriction can cause measured permittivity or transmissivity values to fall below the specimen's actual performance. Measurements may also continue to decline during a test as additional bubbles accumulate within the flow paths. Pre-degassed water minimizes this interference because most of the dissolved gas has already been released before the water reaches the specimen.

Maintaining a consistent water temperature is equally important for obtaining reliable hydraulic measurements. Near room temperature, water's dynamic viscosity decreases by approximately 2.4% with every 1°C increase in temperature. Consequently, a temperature variation of just 5°C can change the flow rate by more than 10%, independently of the specimen's actual hydraulic properties.

The QualiGTX™ DWS 30 addresses these two sources of measurement variation through a combined heating and cooling process. The reservoir is first heated to boiling to release dissolved gases. Once de-airing is complete, the compressor-driven refrigeration circuit lowers the water temperature to the required test setting. Digital PID control then maintains that temperature throughout the testing process. This approach minimizes temperature-related flow variations and reduces the extent of corrections needed to bring measurements to the reference temperature.

De-Aired Water Supply System - QualiGTX™ DWS 30 Technical Specifications

Parameter Specification
Tank Capacity 30 L (7.9 gal)
Temperature Range 15°C to 105°C (59°F to 221°F)
Temperature Control Accuracy ±2°C
Temperature Calibration Accuracy ±0.1°C
Temperature Control Mode Refrigeration and heating
Control System Digital PID, user-adjustable with auto-tuning
Circulation Modes Internal and external
External Circulation Pump 100 W, adjustable flow
Refrigeration System Compressor-based, with overheat and overcurrent protection
Water Connection Hose to downstream test equipment
Voltage 220 V / 50 Hz (110V is also available)
Dimensions (W × D × H) 700 × 550 × 1300 mm (27.6 × 21.7 × 51.2 in)
Weight 60 kg (132 lb)

Delivery time varies upon stock availability. Our standard dispatch and shipping times are generally within 1 week, however for some high demand items the delivery may be extended to 2-3 weeks. If you require these items urgently please contact us to check accurate stock availability and to organize faster shipping methods.

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Important Delivery Information

Delivery time varies upon stock availability. Our standard dispatch and shipping times are generally within 1 week, however for some high demand items the delivery may be extended to 2-3 weeks.

Need it urgently? Contact us here to check stock and organize faster shipping.

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