NImrodA26 wrote:
Could that little tank have been installed to prevent the effect described below???????? I have also witnessed the effects of this on some air lines, although not on aircraft.
"Surge or water hammer, as it is commonly known is the result of a sudden change in liquid velocity. Water hammer usually occurs when a transfer system is quickly started, stopped or is forced to make a rapid change in direction. Any of these events can lead to catastrophic system component failure. Without question, the primary cause of water hammer in process applications is the quick closing valve, whether manual or automatic. A valve closing in 1.5 sec. or less depending upon valve size and system conditions, causes an abrupt stoppage of flow. The pressure spike(acoustic wave)created at rapid valve closure can be high as five(5) times the system working pressure. Unrestricted, this pressure spike or wave will rapidly accelerate to the speed of sound in liquid, which can exceed 4000 ft/sec."
Well, Randy, I am not sure how this applies to this airplane system, but I can speak to "surge" experiences for certain. I made the mistake of eating at a restaurant here that shall remain nameless, but which I greatly hold suspect in causing me to experience said "surge". I did make a rapid change in direction as the fire alarm was sounding in the hotel last night. Instead of completing my escape to safety, I diverted to the men's room where indeed, the rapid valve closure did cause some acoustic sound waves of the most unpleasant variety. They reminded me of my last colonoscopy prep where I expected to have lift off at any second. I can attest that the speed of sound thru a liquid is 4 x that thru plain ol air. There was an awesome acceleration and only through my death grip on the stool did I avoid launching to the moon. Do you suppose it had to do with my small valve size? Well, I am not much of an engineer, but the doc told me he did not find any evidence of my head up there nor did he see any signs of Amelia E. I asked him for a note stating the former for my boss. I plan to use it next time he starts making comments about my general demeanor. So gosh, somehow I got lost in all this??? What was the question??

JR