Appeal No. 95-2580
Application 08/110,958
[i]n one embodiment, the neck is pro-
vided with two diametrically opposed
grooves, running directly into the ampoule.
As the liquid is taken up, air enters via
the grooves to replace the displaced volume
of liquid. While the liquid is being drawn
up, there is a natural tendency for the
greater external pressure to force air in,
thus preventing escape of the contents.
This effect is augmented by the effects of
surface tension which will usually prevent
escape of the liquid even when there is no
pressure differential.
For ease of manufacture, it may be
preferable to provide the channels by
appropriate shaping of the neck. Thus, for
example, to provide two channels, the neck
cross-section can be made oval, the larger
diameter providing the channels and the
smaller diameter gripping the syringe head.
Other configurations are equally possible,
such as a generally rounded triangular
cross-section to provide 3 channels, or a
square cross-section for 4 channels,
although two channels are generally
preferred.
Thus, Rose specifically discloses the use of three or four
venting grooves/channels in the neck of the ampule and, for
ease of manufacture, notes that it may be preferable to
provide such channels by appropriate shaping of the neck, as
may be seen in Figures 9A-9C of Rose.
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