Gehman Tester, ET 02 for determination of the relative stiffness characteristics of vulcanized or thermoplastic rubbers, also called the Gehman procedure.
Low Temperature Tester - Combo TR Gehman Brittleness Compression Set Test System
The TR-Tester, Gehman Tester and Brittleness Tester can be combined using the same base unit and a rig changing system. The combined instrument consists of a base unit with a cooling bath and the electronics. The three different test rigs are then mounted on a carousel. No lifting is necessary when switching from one method to another. An automatic computerized Low Temperature Tester increases the precision up to 5 times. The capacity will also increase with about 50 % and not least the labour time will decrease about 75 %.
For rubber materials there are three important standardised test methods for Low Temperatures.
- TR test according to ISO 2921. This method determines the low temperature characteristics by the temperature retraction procedure. TR10 and TR 30 is often used in materials specifications. The software can present a curve with the elastic retraction up to 70%.
- Gehman test according to ISO 1432. This method measures the relative stiffness as a function of the temperature. The result is presented as the relative stiffness where the stiffness in RT is 1. If the test piece dimension is put into the software it can also calculate the modulus as a function of temperature.
- Brittleness test according to ISO 812. This method determines the lowest temperature at which rubber materials do not exhibit brittle failure when impacted under specified conditions.
- Low Temperature Compression Set according to ISO 815-2. This test measures the elastic recovery after a test piece has been held compressed at low temperature for some time.
TR Tester, ET 01, for determination of low temperature characteristics by the temperature retraction procedure according to ISO 2921 and ASTM D-1329.
The Low Temperature Compression Set Rig performs compression set at low temperatures without having to open the deep-freezer and influence the compression set result has always been a problem.
Brittleness Tester - ET 05 II is used for the automatic determination of Brittleness point according to ISO 812, ISO 974, ASTM D746 and ASTM D2137.
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Qualitest has devised an innovative way to combine several of its Low Temperature testers into a single, multi-purpose system for testing rubber materials. This Low Temperature system is incredibly easy to use and is extremely safe, as no lifting is necessary when switching from one testing method to another.
Qualitest’s TR-Tester, Gehman Tester, and Brittleness Testerare combined into the Low Temperature system consisting of a base unit with a cooling bath and a rig changing system, which is mounted on a carousel to facilitate simple switching between testers. This combined Low Temperature Tester can conduct tests automatically, increasing test precision by up to 400%, capacity by up to 50%, and decreasing labour time by up to 75%.
Qualitest’s Low Temperature system can carry out three important tests on rubber — temperature retraction procedure, relative stiffness tests, and brittleness tests — that meet several internationally recognized standards, including ISO 2921, ISO 1432, ISO 812, and ISO 815-2.