Every plumber I have ever spoken with on the subject of water hammer seem to suffer from an aversion to even attempt to get to the root cause,
And in consequence end up treating the symptoms without knowing the possible cause.
This is an attempt to explain my take on it,
We are all aware that broadly speaking gas or water flowing through a pipe behave similarly,
I mention gas because I have an anecdotal story about something all plumbers can relate
to by virtue of the fact that 9 out of 10 are drivers, and as drivers all know something about the power of their engines it figures that some will know about the importance of
an efficient exhaust system in producing that power,
I know most vehicles have four stroke engines but my anecdote relates to two stroke engines the exhausts of which to some extent behave similarly,
When the exhaust gasses leave the combustion chamber of a two stroke engine they
enter into the part of the exhaust pipe called the “header” this is a parallel tube that
leads towards the expansion chamber which is conical at the start then parallel then reverse conical it then proceeds along another pipe which leads to a silencer and thence
to the tail pipe,
On the face of it one could be excused in thinking that the gasses go in one end and out
the other the shapes in the exhaust having no effect on the flow through of gasses,
On the contrary what happens is the gas leaves the cylinder and goes into the parallel tube
when this gas reaches the expansion cone it expands and in doing so creates a negative
impulse which travels back up the exhaust gasses to the Combustion Chamber and helps suck out more gasses.
It does not end there, when the gasses encounter the second cone positive impulses are created which travel back up the exhaust gasses and help stop the new charge leaving the
said combustion chamber.
Further impulses are created as the exhaust gasses proceed to the open atmosphere
If one extrapolates the amount of occurrences for example a two stroke engine running
at 10000RPM fires 166 times per second, you can visualize all of the tooing and frowing of the gasses in a tiny amount of time.
A similar situation arises with pumped water it maters not what kind of pump is used they
all produce pulses which become inherent in the water and become evident when the
frequency coincides with the available frequencies in the water fitting.
Think along the lines that a circle is a series of straight edges
In the old days of lead pipes it was the norm to run the pipe past the fitting to form a accumulator and use a saddle joint (tee) to connect which suggest that the problem of water hammer must have been far worse then, probably because they used piston pumps,
I am practicing writing a book and any (genuine) comments on readability and understanding and hopefully confirmation that I display a complete lack of patronization, Etc. would be greatly appreciated,
