Janson
# 1992 Eindhoven
New research and development particularly concerning the long-term strain of modern PE resins have created a basis for a simple and adequate method for tightness testing of plastics pressure pipelines. Thus, it is shown that for plastics pipes subjected to constant internal hydraulic pressure, it is quite possible to predict the increase of the tensile strain in the pipe wall during the time of tightness testing solely based upon the initially observed strain increase. This is due to the fact taht the strain plotted in a lin strain versus log time-diagram follows a rectilinear course and consequently does also the water volume change in the pipeline.
Related papers
Author(s) : Hojer, Janson, Oderkerk, Venator
For nearly three decades two technology processes have been available for production of PEX piping by moisture induced silane crosslinking (PEX-b). The first technology, the Sioplas™ process, was invented and patented by Dow Corning. This process requires extruding pipe from a reactive compound composed of silane...
Author(s) : Bassewitz, Janson, Liebel
From Jan 6th 2001 until March 31st 2005 a research project, funded by the German Ministry for Economy and Research had been carried out in order to investigate technical details not yet researched. The results of the project have shown that polymer flexible pipes for district heating are fit for purpose.The research...
Author(s) : Janson, Alferink, Wolters
This paper presents the results of work that was performed at the request of TEPPFA , The European Plastics Pipes and Fittings Association, on the issue of “Combined loading” (external and internal loading) of buried thermoplastics pressure pipes. The work is of great importance for users and designers of...
Author(s) : Janson, Bergstroem, Baeckman, Blomster
When performing strength quality control of PE pressure pipes made of new grades it is important to take the creep vs. time into consideration and not only the common stress vs.time behaviour. Thus, it is just the relation between linear strain and logarithmic time, which will within a reasonable testing time help us...
Author(s) : Janson
Sustainable Development’ is a concept which is often used today, particularly when discussing necessary efforts for preventing persistent environmental problems. It came up as a result of the findings already by the Rome Club et al in the early 70s’, implying that the natural resources of the earth are limited and in...
Author(s) : Alferink, Janson, Olliff
Extensive field trials are being performed in a project sponsored by TEPPFA and APME,to obtain well documented information about the behaviour of buried thermoplastics pipes. as outlined in the paper by Alferink, Bjorklund and Kallioinen (Ref 1). This information is of vital importance to obtain a workable design...
Author(s) : Janson
At the International Conference on Plastics Pipes W in Bath 1988, a paper was presented by the Author called : "Physical ageing of buried PVC sewer pipes as affecting their long-term behaviour". The tests performed on constantly deflected pipes referred to at that time had been running for approximately one year....
Author(s) : Janson
The investigation has indicated that deflected uPVC pipes are subjected to a physical aging process, which gives rise to a lower rate of decrease in the E-modulus than has previously been assumed. Based upon these findings the long term ring stiffness of PVC sewer pipes is determined. Concerning the bending strength...
Author(s) : Janson, Molin
In the Nordic countries common research work concerning buried sewer plastics pipes has been followed by an independent evaluation group led by the authors. This group was founded in 1968 by the Nordic plastic industries in order to create a forum for independent evaluation of all the various research programmes so as...
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