An energy attenuation apparatus in fluid communication with tubing adapted
to convey a liquid under pressure, and including a liquid-conveying unit
in fluid communication with the tubing and having a diameter greater than
the tubing diameter. The liquid-conveying unit has four chambers in
series, at least one of which contains a tube, wherein an annular space
is formed between the inner peripheral surface of the unit and the outer
peripheral surface of the tube. One end of the tube is connected to and
in fluid communication with an inlet or outlet end of the chamber, and
another, free end is spaced by an open gap from the outlet or inlet end
of the chamber. The tube has at least one aperture in the free end and/or
on the peripheral surface thereof for providing fluid communication
between the tube and the chamber.