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Motorized Geosynthetic Permeability Tester

Motorized Geosynthetic Permeability Tester
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Geotextile Permeability Testers
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Motorized Geosynthetic Permeability Tester - QualiGTX™ GPT M

QualiGTX™ GPT M motorized geosynthetic permeability tester measures vertical water flow through geotextiles, geocomposites, and related materials with powered head adjustment. Qualitest North America specified the motorized water level because constant head procedures ask for readings at several head heights, and moving an overflow by hand between each one costs time and repeatability. The control system drives the level to each setting on command. A 10-inch touchscreen carries setup, timing, and the flow volume readout.

Laboratories testing to hydraulic engineering specifications use the QualiGTX™ GPT M where the permeability figure feeds a seepage calculation rather than a pass-fail check. The clamp presents a 20 cm² test area in 304 stainless steel, and automatic supply from an onboard tank keeps the level fed during collection. Heating and cooling hold the water between 5 °C and 60 °C at 0.1 °C display resolution. A dissolved oxygen analyzer covering 0 to 20 mg/L records water condition before the run.

Volume passing the specimen displays digitally as the test proceeds, with automatic timing to 999 s. The cabinet matches the rest of the QualiGGTE bench range at 750 by 720 mm and runs on 220 V single-phase power, with the motorized head assembly bringing weight to 150 kg. Nothing about the installation calls for compressed air or a plumbed water line. Laboratories running several head levels per specimen see the time saving on the first day.

Motorized Geosynthetic Permeability Tester - QualiGTX™ GPT M Applications

The QualiGTX™ GPT M belongs in laboratories supporting water infrastructure, where permeability data feeds design calculations rather than a single acceptance threshold.

  • Dam and Reservoir Engineering: characterization of filter and drainage geosynthetics against seepage models for embankment and core zones
  • Canal and Irrigation Systems: flow capacity measurement on lining and drainage layers carrying continuous water loss risk
  • Water Conservancy Project Laboratories: testing to hydraulic engineering specifications where multi-point head data is expected in the report
  • Flood Defense and Levee Construction: assessment of filter fabrics behind revetments, toe drains, and cut-off structures
  • Hydropower Civil Works: qualification of drainage and separation materials in headrace, tailrace, and spillway construction
  • Geocomposite Drainage Products: cross-plane flow measurement on laminated and multi-layer drainage media
  • Geosynthetics Manufacturing: production testing where the full head-versus-flow curve is supplied with the technical datasheet
  • Consulting and Design Laboratories: generation of input data for seepage and filtration analysis on water retaining structures
  • Research and Method Development: investigation of flow behavior across a range of hydraulic gradients on new material constructions
Motorized Geosynthetic Permeability Tester

Motorized Geosynthetic Permeability Tester - QualiGTX™ GPT M Key Features

The QualiGTX™ GPT M automates the one step that makes multi-point permeability runs slow, then supports it with conditioned water and touchscreen control.

  • Motorized Water Level Adjustment: drives the head to each programmed height without manual repositioning, turning a multi-level run into a sequence rather than a series of setups
  • Automatic Water Supply with Source Tank: feeds the cell from an onboard reservoir during collection, so the level holds without an operator topping it up
  • 10-Inch Touchscreen Control: brings head setting, timing, and results onto one screen and keeps the procedure consistent between technicians
  • Automatic Digital Timing: times collection internally across a 999 s range, removing operator reaction time from the measurement
  • Digital Flow Volume Display: shows water passed through the specimen as the run proceeds, so operators see the result developing rather than waiting for a calculation
  • Heating and Cooling Temperature Control: sets the water anywhere between 5 °C and 60 °C so the 20 °C correction starts from a stable, known condition
  • 0.1 °C Temperature Resolution: resolves the reading finely enough for the viscosity correction to be worth applying
  • Dissolved Oxygen Analyzer: reports oxygen in mg/L, percent saturation, and partial pressure at ±1.5 % FS, documenting water quality in the test record
  • 304 Stainless Steel Specimen Clamp: seals a 20 cm² test area repeatedly without corrosion or distortion in continuous wetted service
  • Standard Bench Footprint: fits 750 by 720 mm on 220 V single-phase power, matching the rest of the QualiGGTE permeability range for laboratory planning

Theory and Method

Vertical permeability is less a single number than a relationship between driving head and the flow it produces. Constant head procedures capture that relationship by holding the specimen at several head levels in turn and recording discharge at each. Plotting head against velocity and fitting a line through the origin gives the coefficient more confidence than one reading at one height. The QualiGTX™ GPT M drives the level to each setting under motor control, which is what makes a multi-point run practical.

The shape of that plot also tells the operator whether Darcy's law still applies. Darcy flow is linear: double the gradient and the discharge doubles. Open, coarse geosynthetics can pass water fast enough that flow turns turbulent at higher heads, and the plot bends away from the line. Catching that bend takes readings across a range of heads, which is the practical argument for powered adjustment over a fixed overflow.

Two conditions have to hold steady while those readings are taken. Water viscosity drops as temperature climbs, so results are corrected to a 20 °C reference. That correction depends on a trustworthy reading, which the QualiGTX™ GPT M supplies at 0.1 °C resolution across a 5 °C to 60 °C range. Dissolved air is the second, since gas leaving solution forms bubbles that lodge in pores and suppress flow. The oxygen analyzer puts that condition on record before collection starts.

Motorized Geosynthetic Permeability Tester - QualiGTX™ GPT M Technical Specifications

ParameterSpecification
Test Area20 cm²
Specimen Clamp Material304 stainless steel
Water Level AdjustmentMotorized
Timing Range0 to 999 s
Temperature Range5 °C to 60 °C
Temperature Resolution0.1 °C
Temperature ControlHeating and cooling
Dissolved Oxygen Range0 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 Resolution0.01 mg/L; 0.1 %; 1 hPa
Control System10-inch touchscreen with automatic digital timing
Water SupplyAutomatic, with source water tank
Voltage220 V, 50 Hz (110V is also available)
Dimensions (W × D × H)750 × 720 × 1,750 mm
Weight150 kg

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Geotextile Permeability Testers