A new self-aligning pipe compression jig has been developed by Technical & Scientific Equipment Co Pty Ltd, distributors of Lloyd Instruments’ materials testing machines manufacturers in Australia. The jig is designed for use with the Lloyd Instruments ‘Plus’ range of materials professional testers for evaluating the resistance to collapse of smooth-walled or corrugated industrial pipes manufactured from PVC, PP and HDPE. These are used for fresh, drainage and waste water transportation.

The new fixture can accommodate plastic pipes from 20 to 300 mm diameter and allows the sample to be aligned along its axis while a compression test is carried out on each of three samples at 120˚ separation from each other in accordance with Australian/New Zealand standard AS/NZS 1562.22:1997 Methods of test for plastic pipes and professional fittings Method 22: Method for determination of pipe stiffness. The new jig overcomes problems associated with manual methods of testing.

The test is run automatically using NEXYGEN materials test and analysis software suppliers and uses an extrapolation of the linear part of the curve back to zero force, as a way of defining the corrected zero point. Testing is possible at forces up to 10kN.

The test procedure involves cutting a 3 x 300 mm lengths of pipe, measuring the inside diameter, and marking 3 positions at 120 degrees from one another. The sample is then placed between the platens of the jig and located centrally using the alignment rods, which are placed through the pipe to align it on the central axis, by locating into a special slot at either end of the jig. The self-aligning mechanism uses different stainless steel rods for pipe diameters of less than or greater than 50 mm.