{"product_id":"digital-geotextile-permeability-tester","title":"Digital Geotextile Permeability Tester","description":"\u003cdiv\u003e\n\u003cdiv\u003e\n\u003ch2\u003eDigital Geotextile Permeability Tester – QualiGTX™ GPT D\u003c\/h2\u003e\n\u003cp\u003eThe QualiGTX™ GPT D Digital Geotextile Permeability Tester measures vertical water flow through single-layer and multilayer geotextile specimens under no-load conditions. Qualitest North America designed this apparatus around ASTM D4491, the permittivity test method widely used by North American laboratories. Its 10-inch color touchscreen simplifies test configuration, timing, and result monitoring. It provides laboratories performing routine acceptance testing with standards-based measurements without requiring the investment in a fully automated testing system.\u003c\/p\u003e\n\u003cp\u003eThe instrument accommodates geotextile specimens up to 20 mm thick within a Ø50 mm high-strength 304 stainless steel clamping assembly. It applies a hydraulic head differential of up to 250 mm H₂O. The integrated heating and cooling system regulates water temperature from 5 °C to 60 °C, with a resolution of 0.1 °C. A dissolved oxygen measuring device verifies water conditions before testing, while automatic timing operates across a 999-second range.\u003c\/p\u003e\n\u003cp\u003eThe lateral two-unit water supply stabilization system quickly establishes the required water head and minimizes surface fluctuations, reducing the waiting time before measurements can begin. The unit features a compact 750 × 720 mm footprint, weighs 120 kg, and operates on standard single-phase 220 V power without requiring a dedicated utility connection. Its automatic water supply maintains a constant hydraulic head throughout data collection without manual refilling. This combination of controlled testing conditions and straightforward operation makes it a practical upgrade for laboratories transitioning from manual permeameters.\u003c\/p\u003e\n\u003ch2\u003eDigital Geotextile Permeability Tester – QualiGTX™ GPT D Applications\u003c\/h2\u003e\n\u003cp\u003eThe QualiGTX™ GPT D is suitable for laboratories requiring consistent, reliable geotextile permeability measurements for routine testing and quality verification rather than advanced research applications.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003eGeotextile Manufacturing Quality Control: Performs routine production lot inspections to verify permittivity values against declared specifications before products are shipped.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003eConstruction Materials Testing Laboratories: Supports acceptance testing of filter and separation geotextiles supplied for road, railway, and earthworks projects.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003eContractor and Site Laboratories: Verifies that delivered geotextile materials comply with project specifications before installation in subgrades or drainage systems.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003eDistributor and Importer Verification: Provides independent testing to confirm supplier declarations and assess incoming material shipments.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003eHighway and Municipal Drainage Work: Evaluates water flow capacity in edge drain wraps, trench drainage fabrics, and separation layers.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003eLandfill and Containment Projects: Checks whether drainage and protection geotextiles installed above liner systems satisfy specified design flow requirements.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003eErosion Control and Slope Drainage: Tests filter fabrics installed behind revetments, gabions, and retaining structures.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003eTechnical Colleges and University Laboratories: Provides practical instruction in the geotextile permittivity method using equipment aligned with the published testing procedure.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003eProduct Development Screening: Enables preliminary comparisons of fiber types, basis weights, and bonding variables before undertaking comprehensive material characterization.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eStandards\u003c\/h2\u003e\n\u003cp\u003eThe QualiGTX™ GPT D complies with the apparatus requirements of the recognized North American test method for determining the water permeability of geotextiles in their uncompressed condition.\u003c\/p\u003e\n\u003cp\u003e- ASTM D4491 – Standard Test Methods for Water Permeability of Geotextiles by Permittivity\u003c\/p\u003e\n\u003ch2\u003eDigital Geotextile Permeability Tester – QualiGTX™ GPT D Key Features\u003c\/h2\u003e\n\u003cp\u003eThe QualiGTX™ GPT D combines touchscreen operation with a conditioned water supply in a compact, single-cell configuration. Its integrated controls simplify testing procedures and allow operators to concentrate on obtaining accurate measurements.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003e10-Inch Color Touchscreen Control: Combines test configuration, timing, and result monitoring on a single display, allowing technicians to view measurements directly without manually recording gauge readings.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003eAutomatic Digital Timing: Controls the measurement interval using an internal clock across a 999-second range, eliminating timing errors associated with manual stopwatches.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003eLateral Two-Unit Supply Stabilization: Quickly establishes the target hydraulic head and stabilizes the water surface, minimizing delays before measurements begin.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003eAutomatic Water Supply: Maintains a consistent hydraulic head throughout the collection period without requiring manual water replenishment.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003eControlled Temperature Water System: Heats or cools the water supply between 5 °C and 60 °C, supporting accurate correction of test results to the 20 °C reference temperature.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003e0.1 °C Temperature Resolution: Provides precise temperature readings to support the viscosity corrections required by the test method.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003eDissolved Oxygen Measuring Device: Checks water conditions before testing and helps identify entrained air that could reduce measured flow by obstructing specimen pores.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003eHigh-Strength 304 Stainless Steel Clamp: Secures and seals specimens consistently while providing resistance to corrosion and deformation during extended operation.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003eIntegrated Source Water Tank: Supplies water to the test cell through an onboard reservoir, eliminating the need for a permanently connected water supply at the testing bench.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003eDirect Result Display: Presents the calculated measurement upon test completion, allowing operators to proceed to the next specimen without performing separate calculations.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003cp\u003eCompact Single-Cell Frame: Requires only a 750 × 720 mm footprint and operates using standard single-phase 220 V power, making it suitable for laboratories without specialized utility connections.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eTheory and Method\u003c\/h2\u003e\n\u003cp\u003eWater flowing perpendicular to a geotextile's plane follows Darcy's law under laminar flow conditions. Accordingly, the discharge rate increases in proportion to the hydraulic head difference across the fabric. The QualiGTX™ GPT D secures the specimen within a Ø50 mm aperture, maintains a measured hydraulic head, and records the volume of water passing through the material over a specified time interval. The resulting discharge measurement, evaluated against the known hydraulic head, forms the basis of the test. The instrument maintains stable head conditions, water temperature, and water quality to minimize variations during measurement.\u003c\/p\u003e\n\u003cp\u003eThe test method determines permittivity, calculated by dividing the flow rate by the specimen area and then by the hydraulic head. The resulting value, expressed in reciprocal seconds (s⁻¹), characterizes the geotextile independently of its thickness. This is important because nominal specimen thickness can change during packaging, transportation, and handling, making thickness-dependent permeability coefficients less suitable for direct comparisons between fabrics. When required for design calculations, the permeability coefficient can be obtained by multiplying permittivity by the nominal specimen thickness.\u003c\/p\u003e\n\u003cp\u003eWater viscosity decreases as temperature increases. Consequently, measurements taken without temperature correction can reflect changes in water temperature as well as the actual characteristics of the geotextile. The test method standardizes results against a reference temperature of 20 °C, making reliable temperature measurement essential. The QualiGTX™ GPT D provides water heating and cooling between 5 °C and 60 °C, with temperature readings available at 0.1 °C resolution. Its dissolved oxygen measuring device provides an additional water quality check. Dissolved gases can escape from the water and form bubbles within the specimen, obstructing pores and reducing the measured flow rate. Verifying water conditions helps identify this potential source of measurement variation.\u003c\/p\u003e\n\u003ch2\u003eDigital Geotextile Permeability Tester - QualiGTX™ GPT D Technical Specifications\u003c\/h2\u003e\n\u003ctable class=\"table table-style-align-center\" align=\"center\" border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"800\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eParameter\u003c\/th\u003e\n\u003cth\u003eSpecification\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum Head Differential\u003c\/td\u003e\n\u003ctd\u003e250 mmH₂O (2,450 Pa)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpecimen Clamp Inner Diameter\u003c\/td\u003e\n\u003ctd\u003eØ50 ± 0.5 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaximum Specimen Thickness\u003c\/td\u003e\n\u003ctd\u003e20 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSpecimen Clamp Material\u003c\/td\u003e\n\u003ctd\u003eHigh-strength 304 stainless steel\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTiming Range\u003c\/td\u003e\n\u003ctd\u003e0 to 999 s\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTemperature Range\u003c\/td\u003e\n\u003ctd\u003e5 °C to 60 °C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTemperature Resolution\u003c\/td\u003e\n\u003ctd\u003e0.1 °C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTemperature Control\u003c\/td\u003e\n\u003ctd\u003eHeating and cooling\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDissolved Oxygen Measurement\u003c\/td\u003e\n\u003ctd\u003eIncluded\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eControl System\u003c\/td\u003e\n\u003ctd\u003e10-inch color touchscreen\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWater Supply\u003c\/td\u003e\n\u003ctd\u003eAutomatic, with source water tank\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHead Stabilization\u003c\/td\u003e\n\u003ctd\u003eLateral two-unit stabilizing system\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eVoltage\u003c\/td\u003e\n\u003ctd\u003e220 V, 50 Hz (110V is also available)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDimensions (W × D × H)\u003c\/td\u003e\n\u003ctd\u003e750 × 720 × 1,750 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e120 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"Qualitest USA LC","offers":[{"title":"Default Title","offer_id":53459730530615,"sku":null,"price":100.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0786\/1859\/1543\/files\/entry-level-geotextile-permeabil.webp?v=1793363783","url":"https:\/\/qualitest.us\/pt\/products\/digital-geotextile-permeability-tester","provider":"Qualitest USA LC","version":"1.0","type":"link"}