In a message dated 30/08/00 18:11:32 GMT Daylight Time,
kenwhit@kenwhit.demon.co.uk writes:
<< I don't think this would be a long term solution. The pumping of
volatile hydrocarbons is a classic problem in the chemical industry. The
answer is that there is no substitute for liquid head. Pressurising with
nitrogen or any other gas leads to bubbles of nitrogen etc. The only
other solution is a submersible or centrifugal pump at the low point of
the system. In the short term pressurising with a gas overcomes the
cavitation problem, but that is because the liquid reaching the pump is
not yet saturated with gas >>
Comment appreciated. My view was that whatever the source of the air/gas
bubble, a standing pressure gradient would move it through the pump, allowing
normal operation when fuel arrives. This is similar to priming a pump which
will not operate initially due to being air filled. Although a standing
pressure indeed increases the percentage of dissolved gas available for
bubbles when heated, they should still move through the pump. And as in my
real-life event, heat induced vapour lock may not always be the source.
Graham
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