Temperature-Controlled Geotextile Permeability Tester

Temperature-Controlled Geotextile Permeability Tester

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Temperature-Controlled Geotextile Permeability Tester
  • Temperature-Controlled Geotextile Permeability Tester
Temperature-Controlled Geotextile Permeability Tester
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Temperature-Controlled Geotextile Permeability Tester

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Temperature-Controlled Geotextile Permeability Tester – QualiGTX™ GPT T

The QualiGTX™ GPT T geotextile permeability tester determines the vertical water flow rate through geotextiles and related materials under no-load conditions, with test water maintained between 10 °C and 60 °C. Its thermostatically regulated water circuit addresses temperature-related changes in water viscosity, reducing test variability that cannot be eliminated through specimen replication alone. The computer-controlled system automatically positions the water head, measures test duration, and calculates the vertical permeability coefficient. Test reports are generated in a format suitable for uploading or printing.

Designed for geosynthetics manufacturers, civil engineering laboratories, and construction quality control departments, the QualiGTX™ GPT T supports the evaluation of filtration and drainage fabrics before installation. Its 304 stainless steel specimen clamp accommodates samples measuring 50 mm in diameter and up to 20 mm thick. Operators can select any head height within a maximum differential of 250 mm. The instrument automatically identifies the zero water level and maintains the required level through a metered water supply system rather than an overflow weir. A dissolved oxygen analyzer also verifies water quality before testing.

The automated 70 mm head differential sequence completes measurements across the 0.8 to 0.2 head range without manual intervention, with timing accuracy of 0.1 s. A 36 L stainless steel water tank, PID temperature control system, and 15 L/min circulation pump maintain stable test conditions. Temperature deviation is corrected to ±0.1 °C, providing the measurement basis for viscosity correction in the final results. With an overall cabinet width of 1,150 mm, the tester fits standard laboratory floor layouts.

Temperature-Controlled Geotextile Permeability Tester – QualiGTX™ GPT T Applications

The QualiGTX™ GPT T is suitable for laboratories that require dependable cross-plane water flow measurements across different seasons, project locations, and independent verification procedures.

  • Nonwoven and Woven Geotextile Production: Performs routine production lot inspections to verify declared permittivity and water flow-rate values before materials leave the manufacturing facility.

  • Roadway and Highway Subgrade Work: Evaluates separation and filtration geotextiles installed between soft subgrade soils and granular base materials.

  • Port, Harbor, and Waterway Construction: Assesses geotextiles used in revetments, quay backfill, and dredged material containment under sustained hydraulic loading.

  • Canal, Reservoir, and Embankment Drainage: Verifies that filtration layers allow seepage water to pass while retaining fine soil particles.

  • Retaining Wall and Slope Drainage Systems: Measures the flow capacity of geotextiles surrounding drainage aggregate and used in blanket drain installations.

  • Landfill Leachate Collection Layers: Checks whether protective and drainage geotextiles installed above liners satisfy specified design flow requirements.

  • Agricultural and Land Drainage: Evaluates wrapping materials used with perforated drainage pipes and trench drainage systems.

  • Independent Testing and Certification Houses: Conducts verification and arbitration testing to validate supplier results for tender submissions and material acceptance documentation.

  • Fiber and Fabric Development Programs: Examines relationships between pore structure, basis weight, and needling processes through measured hydraulic conductivity results.

Temperature-Controlled Geotextile Permeability Tester – QualiGTX™ GPT T Key Features

The QualiGTX™ GPT T combines thermostatically regulated water circulation, automatic head positioning, and computerized result processing to deliver consistent geotextile vertical permeability measurements.

  • 10 °C to 60 °C Thermostatic Water Circuit: Heats or cools test water to the selected temperature and maintains it within ±0.5 °C, minimizing seasonal temperature variations during comparative testing.

  • Automated 70 mm Head Differential Sequence: Automatically performs the test across the 0.8 to 0.2 head range, ensuring consistent procedures between different operators.

  • Automatic Zero Water Level Positioning: Identifies the reference water level without manual leveling or shimming, reducing specimen setup time.

  • Freely Programmable Head Height: Allows operators to select any water level within the 250 mm differential range according to the applicable test procedure or specimen requirements.

  • Metered Water Supply Flow System: Replenishes water passing through the specimen at a controlled rate to maintain a stable driving head throughout the measurement.

  • Dissolved Oxygen Measurement System: Measures and displays dissolved oxygen in mg/L, percentage saturation, and partial pressure, allowing water quality to be verified and recorded.

  • Automatic Volume Collection and Timing: Measures collected water volume alongside elapsed time with 0.1 s resolution, eliminating reliance on manual stopwatch readings.

  • Automatic Permeability Calculation and Reporting: Processes measured flow data to determine the vertical permeability coefficient and generates reports for uploading or printing.

  • Selectable Test Configurations: Supports multiple vertical permeability testing protocols through the control software, allowing different reporting formats to be handled by one instrument.

  • Computer Control with Simple Operation: Provides guided test setup and parameter storage through the control computer, simplifying operation and reducing training requirements for laboratory personnel.

  • Temperature Deviation Correction: Corrects measured temperature deviation to an accuracy of 0.1 °C, providing a reliable basis for water viscosity adjustments.

  • User-Adjustable PID with Auto-Tuning: Allows the thermal control loop to be adjusted and automatically tuned to suit laboratory ambient conditions rather than relying exclusively on fixed factory settings.

  • 304 Stainless Steel Water Tank and Clamp: Provides corrosion resistance during continuous water exposure and repeated specimen clamping operations.

  • 304 Stainless Steel Water Line Fittings: Maintain a corrosion-resistant wetted flow path, preventing rust contamination that could affect specimens or distort flow measurements.

  • Electrostatic Powder-Coated Working Vessel: Provides an additional protective surface finish over stainless steel for reliable operation in humid laboratory environments.

Theory and Method

Vertical permeability testing evaluates cross-plane water movement by measuring the volume of water passing through a unit area of geotextile under a unit hydraulic head over a specified period. Darcy's law describes this relationship when the water flow remains laminar. The QualiGTX™ GPT T applies a defined head difference across the clamped specimen, collects the water passing through the material, and calculates the ratio of collected volume to specimen area, hydraulic head, and elapsed time. This value represents permittivity. Multiplying permittivity by the specimen thickness produces the permeability coefficient used in drainage design calculations.

Water temperature is a major factor affecting vertical permeability measurements. At 10 °C, water is approximately 1.6 times as viscous as it is at 30 °C. Consequently, an identical geotextile specimen allows noticeably less water to pass through it at the lower temperature. Standard test methods account for this difference by converting measured results to a reference temperature using a viscosity ratio. The accuracy of this correction depends directly on the reliability of the temperature measurement. The QualiGTX™ GPT T maintains bath temperature within ±0.5 °C and corrects temperature deviation to ±0.1 °C.

Dissolved gases represent another potential source of measurement error. Air dissolved in water can form microscopic bubbles within the pore structure of nonwoven geotextiles. These bubbles obstruct flow channels and reduce the measured water flow rate. To address this factor, the QualiGTX™ GPT T includes a dissolved oxygen analyzer with a measurement range of 0 to 20 mg/L. Operators can verify water quality before testing and include the readings in the test report. Consistent hydraulic head is equally important for reliable results. The instrument uses a metered water supply to replace the water passing through the specimen, maintaining the selected hydraulic gradient throughout the measurement.

Temperature-Controlled Geotextile Permeability Tester - QualiGTX™ GPT T Technical Specifications

Parameter Specification
Maximum Head Differential 250 mm
Specimen Clamp Inner Diameter Ø50 ± 0.5 mm (304 stainless steel)
Maximum Specimen Thickness 20 mm
Timing Range 0 to 9,999 s
Timing Accuracy 0.1 s
Temperature Measurement Range 0 °C to 110 °C
Temperature Control Range 10 °C to 60 °C
Temperature Control Accuracy ±0.5 °C
Thermometer Accuracy 0.1 °C
Temperature Correction Accuracy ±0.1 °C
Dissolved Oxygen Range 0 to 20 mg/L; 0 to 200 %; 0 to 400 hPa
Dissolved Oxygen Accuracy ±1.5 % FS
Dissolved Oxygen Repeatability ±0.5 % FS
Dissolved Oxygen Resolution 0.01 mg/L; 0.1 %; 1 hPa
Water Supply Tank Capacity 36 L
Temperature Control Modes Cooling and heating
Cooling Method Compressor unit
Temperature Control PID with auto-tuning
Compressor Power 550 W
Internal Circulation Pump Power 100 W
Circulation Pump Flow Rate 15 L/min
Total Power 1 kW
Dimensions (W × D × H) 1,150 × 670 × 1,580 mm
Weight 180 kg

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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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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