TESTING AT NON-AMBIENT TEMPERATURES

The properties of materials at high and low temperatures are of major interest to engineers. In most cases you can add an environmental chamber or furnace to your testing system, which allows you to perform the required tests. The following section offers some guidance on the selection and use of high and low temperature equipment.

Environmental chambers cover a typical temperature range of -150°C to +600°C and provide a large volume suitable for a wide range of tests. Instron® chambers use forced convection heating/cooling in which a fan is used to circulate hot or cold air within the chamber. The specimen is located near the center of the chamber using suitable grips. The grips are attached to the testing system using pull rods or push rods that extend through ports in the chamber top and bottom. A hinged door containing a window allows access to the load string. The chamber can be rigidly-mounted or use a roller mounting, which allows the chamber to be moved back from the test space when not in use. Removable wedges in the front of the chamber allow the chamber to be moved backwards without the need to remove the load string first and are a major convenience, especially for users with a large variety of tests to perform. Wedges may be standard or optional, depending on the model.

Testing below ambient temperatures requires the use of a refrigerant gas such as liquid nitrogen (LN2) or carbon dioxide (CO2), or mechanical cooling using a specially constructed chamber. LN2 allows lower temperatures to be achieved and is the most common choice of cooling method. The cooling gas is injected into the chamber via a solenoid valve controlled by the chamber temperature controller.

A range of grips compatible with high and low temperatures are available including wedge action and pneumatic side action type. Pull rods and push rods to suit your combination of model number, chamber, grip and load cell are available. The vast range of combinations makes it best for us to configure the pull rods and push rods needed for a particular system as part of any quotation.