| description abstract | This paper gives a brief account of the developments carried out in the Northwich, England, laboratories of Imperial Chemical Industries Limited (ICI) which led to this method of design being used in the first commercial high-pressure polyethylene plant, which went on stream in 1939 at a working pressure of 150 MPa (approximately 22,000 psi). The essential requirement was to determine the lowest value of the bursting pressure, but the difficulty in this is that experimenters tend to get erroneously high values because they raise the pressure too fast. An analytical approach, based on stress/strain relations derived from torsion tests, was therefore developed for comparison. The problems of increasing scale were then resolved by building and operating progressively larger laboratory vessels, leading to those of 10-liter capacity which were used for the polyethylene pilot plant in 1937, operating at pressures up to 200 MPa (approximately 29,000 psi). | |
