Product category:
Materials Testing
News Release from: Lloyd Instruments | Subject: Self-aligning pipe compression jig
Edited by the Manufacturingtalk Editorial
Team on 11 January 2008
Self-aligning compression jig tests
plastics pipe
A self-aligning pipe compression jig evaluates the resistance to collapse of smooth-walled or corrugated pipes manufactured from PVC, PP and HDPE.
Technical and Scientific Equipment Co Pty, distributors of Lloyd Instruments' materials testing machines in Australia, has developed a self-aligning pipe compression jig The jig is designed for use with the Lloyd Instruments 'Plus' range of materials testers in order to evaluate the resistance to collapse of smooth- walled or corrugated pipes manufactured from PVC, PP and HDPE
This article was originally published on Manufacturingtalk on 7 Oct 2002 at 8.00am (UK)
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The jig can accommodate plastics pipes from 20 to 300mm diameter and allows the sample to be aligned along its axis while a compression test up is carried out on each of three samples at 120 deg separation from each other.
The results are used to automatically calculate the stiffness of the pipe in three directions at 120 deg separation in accordance with Australian/New Zealand standard AS/NZS 1562.22:1997 Methods of test for plastics pipes and fittings: 'Method 22: Method for determination of pipe stiffness'.
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Testing is possible at forces up to 10kN.
* Procedure - the test procedure involves cutting a 3 x 300mm lengths of pipe, measuring the inside diameter, and marking three positions at 120 deg 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 50mm.
During the test, the sample is compressed by 5% of its original diameter at a speed selected according to the pipe diameter and after correcting for the initial contact.
The second sample is then tested at 120 deg, and the third at 240 deg from the first.
A special calculation of the pipe stiffness is made using the average of the three test results.
The new jig overcomes many problems associated with manual methods of testing, said Lloyd Instruments to manufacturingtalk.com, which required the operator to hold the sample near the centre line of the plates until the plates contact the sample.
Manual positioning is potentially dangerous since if the operator lets go too soon the pipe rolls, which runs the risk of testing with the sample off-axis, or with the potential for damaging or reducing the accuracy of the load cell.
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