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Extensometers for materials testing

High Temperature Clip-On Gages (700 °C) – Model 7641

Designed for fracture mechanics testing in environmental chambers where the entire gage must be exposed to elevated temperatures. These capacitive sensors may be used up to 700 °C (1300 °F) without any cooling.

The Model 7641 INTRODUCES SEVERAL IMPROVEMENTS to Epsilon’s offerings for an uncooled, axial extensometer including:

  • A new body style to optimize mechanical performance and reduce weight and size
  • A new probe design that also provides many improvements including lower noise, better frequency response, improved flexibility and durability
  • Increased operational temperature
  • The ability to store calibrations of multiple extensometers with one signal conditioner

Epsilon extensometers are COMPATIBLE WITH VIRTUALLY EVERY BRAND OF TEST EQUIPMENT and can be supplied with the correct connector to plug in directly.

WITH EPSILON’S 20+ YEAR HISTORY OF SERVICE

to the materials testing community, you know we will be there to stand behind our products when your critical application requires it.

These COD gages use a high-temperature capacitive sensor and do not require any cooling. They will operate up to the maximum temperature limit of most environmental chambers used in materials testing. The Model 7641 is ideal for determination of fracture mechanics parameters such as JIC, KIC, R-curve, fatigue crack growth rate (da/dN), and testing to standards such as E1820, E399, E647, etc. All units can be displaced slightly in compression for ease of installation.

The COD gage is supplied with the advanced DT6229 controller. The standard output is 0-10VDC analog signal, factory calibrated with the COD gage. This system provides a number of functional enhancements including: high speed digital output, built in calibration and tare functions, analog and digital filters, and more.

The 7641 is readily interfaced with most existing test controllers and may be directly connected to a data acquisition system or chart recorder, or directly to a PC. The 7641 may be used for strain controlled tests such as JIC.

Download Data Sheet

  • May be left on through specimen failure.
  • Improved performance at high temperature.
  • Improved noise rejection, resolution, and accuracy.
  • Improved clearance with most clevis designs.
  • Improved linearity and reduced stiffness.
  • Reduced size and weight, and improved high frequency performance.
  • All standard models are suitable for cyclic testing.
    • >25 Hz is typical for 10mm GL and larger, up to 100 Hz for some configurations
    • Typically limited by the user’s test apparatus, software settings, and filter selection
  • Digital controller and power supply included. Provides high level DC voltage output with low noise. Easily interfaced to test controllers, data acquisition boards and chart recorders.
    • Includes high speed analog and digital outputs
    • Intuitive web-based user interface for setup, calibration, and data acquisition
    • Built-in calibration reference and auto-zero features
    • Multiple extensometer calibration files may be loaded for use with one controller
    • Multiple temperature-specific calibrations may be stored
    • Selectable analog and digital filter options from 2 Hz to 3 kHz
  • Ships fully calibrated with electronics (traceable to NPL (UK)) with user specified voltage output.
  • Mechanical over-travel protection.
  • All standard units meet existing, ASTM E399, ASTM E1820 and ISO 12135 requirements for accuracy.
  • Durable stainless steel knife edges.
  • Includes high quality foam lined case.
  • Rugged, dual flexure design for strength and improved performance. The next-generation design enables cyclic testing at much higher frequencies.

Download Data Sheet

Analog Output: User specified, +/-5 VDC or +/-10VDC typical, ±10.8VDC rail

Digital Output: 24 bit high speed Ethernet output with built-in web interface

Linearity: 11 point linearization, ≤0.1% FS typical linearity

Resolution: <55 PPM (0.006%FS) RMS @ 4 kHz, <6 PPM (0.0006%FS) @ 100 Hz

Cyclic Testing: >25 Hz typical @ 10mm GL, >10 Hz @ 5mm GL

Analog Filter: Selectable 100 Hz analog and 2 Hz – 3 kHz digital filters

Temperature Range: Ambient to 700 °C (1300 °F). Use up to 800 °C is possible – contact Epsilon for details. Springs may require periodic adjustment or replacement after long-term testing above ~600 °C.

Temperature Sensitivity (Gain): Temperature Sensitivity (Offset): 20 PPM / °C (0.002%FS/°C) typical

Sensor Cable: 0.7 m (2.5 ft) tri-axial high temperature cable, plus 1.5 m (5 ft) room temperature extension cable

Operating Force: 1-5 kg typical, depending on model

Environment: Recommended for elevated temperature testing in dry air or inert / non-corrosive gases

Power: Includes power supply for your country (specify)

 

ce-certified

 

Download Data Sheet

  • Connectors to interface to nearly any brand test equipment
  • Bulkhead adapters for vacuum chambers
  • Dual-channel DT6229 controller available
  • Bolt on knife edges for attachment to test specimens without machined attachment points

Download Data Sheet

Product Videos

 

COD gage for high-temperature fracture mechanics and fatigue crack growth testing up to 700 °C

 

Ordering Information

Click table options to configure

Gauge Length

mm or inches #
3.0 mm -003M¹ 003M
5.0 mm -005M 005M
6.0 mm -006M 006M
10.0 mm -010M 010M
12.0 mm -012M 012M
0.20 in -0020 0020
0.25 in -0025 0025
0.40 in -0040 0040
0.50 in -0050 0050

Measuring Range

extension #
+2.5 mm * -025M² 025M
+4.0 mm * -040M 040M
+6.0 mm ** -060M 060M
+8.0 mm ** -080M 080M
+10.0 mm ** -100M 100M
+12.5 mm ** -125M 125M
+.10 in * -010T² 010T
+.25 in ** -025T 025T
+.40 in ** -040T 040T
+.50 in ** -050T 050T

Model Number:  7641_ _ _ __ _ _ _

Model Number:

7641_ _ _ __ _ _ _

Model 7641 Available Versions: ANY combination of gauge length and measuring listed above is available, except as noted. Other configurations may be available with special order; please contact Epsilon to discuss your requirements.

¹Special order, <5 Hz typical
²Suitable for front-face mounting only
* Tilted cable exit
** Vertical cable exit

Example: 7641-010M-060M: 10.0 mm gauge length,+6.0 mm measuring range

Download Product Guide

Axial and High Temperature

Shunt Calibration

SCM Shunt Calibration Modules

Knife Edge Options

Available for Epsilon Extensometers

Repairs/Service

If your unit is in need of service, calibration or repair, initiate the RMA process with us and we will be happy to assist.

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Download Catalog

2017 Extensometer Catalog, Version 109 is now available! Not finding something you’re looking for? Ask us about a custom quote.