Maritime Applications for Plastics Piping # 1970 Southampton
An early record of the use of a l'plastictl or flexible pipe is in 1733 when the Re\/. Stephen Hales wished to measure the blood pressure of a horse. He had a brass canula, to insert into an artery, and a long glass tube; but he had to find a flexible pipe to connect the two. His solution was to use the trachea, or windpipe, of a swan. Will? this equipment he then demonst?ated that the arterial pressure was sufficient to raise the blood to ateighto: 81311 in the glass tube. This experiment, for which Hales !s famous, illustrates that the scientist always has to exercise his ingen.~ity in making do with the pipes (~Iastic or otherwise) at his disposal. Obviously, to do this effectively he must have accurate and reliable information about the materials of which they are made.
The first marine laboratories appeared on the scene about 100 years after Hales; when the beauty and fascination of marine animals and plants was being appreciated by scientists and lay-men alike. These early marine laboratories used the materials of the time to handle their sea water, and we can guess that the main preoccupation of their engineers was, as now, to use materials which withstood the corrosive action of the seawater and yet did not harm the animals living in it. In addition, of course, the materials must satisfy the mechanical requirements of the installation, which are different in different parts of the system. Thus at the Plymouth Laboratory, which was opened in 1888 the supply system consisted of a cast-iron main, the distribution system was made of ebonite tubes and fittings, while the return system, which was not under pressure, consisted of ordinary glazed stone-flare pipes and ooen culverts.