AIR PERMEABILITY, SOFTNESS & SMOOTHNESS

Combination of low, standard and high pressure Gurley Densometers and smoothness testers
   
Our flagship instrument.  The Model 4340 combines the abilities of our textile, standard and high pressure Densometers, S-P-S Testers as well as our programmable digital timers and provides a reading in seconds, thus reducing the time required to test a material. By utilizing state-of-the-art mass flow technology, the Model 4340 can accurately test both low and high flow materials traditionally tested between 0 and 50,000 'Gurley Seconds'. At the end of either an automatic or manual test, the user can then toggle between Gurley units, Bendtsen, Sheffield or Bekk equivalent units. Conform to TAPPI T-460 & TAPPI T-536-88, ASTM D-726-58 & D-202-77, APPITA/AS 1301-420, BS 5926, CPPA D-14, ISO 5636/5, SCAN P-19 & P-53.

4340 SPECIFICATIONS

Gurley Densometers

Densometers are the accepted standard for measuring the porosity of materials such as papers, wovens, plastics and membranes. All Densometers measure the time required for a given volume and of air (25cc to 400cc) to flow through a standard area of material being tested under light uniform pressure. Certain models, such as the S-P-S Tester, are also used to measure surface smoothness and material softness. Manual and automatic units available. Conform to TAPPI T-460, ASTM D-726-58 & APPITA/AS 1301-420, BS 5926, CPPA D-14, ISO 5636/5, D-202-77, SCAN P-19 & P-53.

MANUAL DENSOMETER SPECIFICATIONS AND ACCESSORIES

Gurley High Pressure Densometers

High Pressure Densometers are the accepted standard for measuring the porosity, air-permeability or air-resistance of materials having low permeability. Typical materials include coated papers, plastics and membranes. High Pressure units are recommended whenever a standard unit would yield excessive measurement times. Manual and automatic units available. Conform to TAPPI T-536-88 and ASTM D-726-58, Method B.

HIGH PRESSURE DENSOMETER SPECIFICATIONS AND ACCESSORIES

Gurley Permeometers

The Gurley Model 4301 Permeometer measures the porosity or air-permeability of materials where air flow is an important characteristic relative to their use. These materials might be non-woven or woven textiles, filter and cloth felts, some types of blotting, saturating and absorbent bag papers as well as meshes. Conform to TAPPI T-251, ASTM D-737, DATM 70.0-70 and ISO 5636/1.

PERMEOMETER SPECIFICATIONS 

Helping you decide which is right for you!

The essential difference between these instruments is that the Permeometer tests materials primarily designed to allow air flow, while the Densometers typically test materials of lower permeability where air flow is a secondary characteristic. The means of instrument operation and resulting units of measure are related but stated differently. The Permeometer measures actual flow in cubic feet per minute, per square foot of material (at 0.5" W.C gage pressure drop). The Densometers measure the time required to force a known volume of air through one square inch of material (at 1.22" to 12.3" W.C. gage pressure).

Some crossover models exists for materials of "borderline porosity", in particular those which can be tested on the Model 4118 Textile Densometer (with 5 oz. cylinder) and Model 4301 Permeometer. The choice of instrument is typically based on the permeability of the sample and which device provides more useful data. Generally speaking, a Permeometer cannot be used to test ordinary papers.

Porosity Conversions between Gurley Orifices, Test Pressures and Volumes

There exists a linear relationship between material test results for Gurley low, standard and high pressure Densometers.  The benchmark for these instruments is what is commonly referred to as "Gurley Seconds", which denotes to the time needed to pass 100cc of air through 1.0 square inch of material at standard pressure.  Depending on the time it takes to pass air under these conditions, a user may prefer to increase or decrease the test time (after all - who wants to wait) by increasing or decreasing the pressure and/or orifice size.  For example, if a sample takes 2,500 Gurley Seconds (i.e., 100cc using 1.0 sq.in. and standard pressure) on a standard Densometer (Model 4110 or 4190), the same sample would only take 100 seconds on a high pressure Densometer (Model 4150 or 4250) using the same orifice and 10cc of air.  Please refer to the following chart for more information.  Note that the Model 4340 Automatic Densometer and Smoothness tester does not wait for the air to displace; the Model 4340 uses mass flow technology for instantaneous results.  Still, the Model 4340 mirrors the output of all Gurley manual Densometers regardless of the orifice or volume used.