The Purely Yours pump does not have a filter.  It does not need one,
because the kit is a CLOSED system.  There is a silicone diaphragm that
looks like a large, upside down thimble at the top of each collection
kit.  The pump draws air out of these diaphragms, and the diaphragms
collapse, like a balloon, inducing a relative vacuum in the nipple
tunnel, drawing in the nipple so the breast is compressed against the
breast cup to push milk out and the small muscles that hold milk in are
stretched and allow milk out.  When the diaphragms refill, the vacuum is
relieved so the nipple is released and the breast can refill.  At no
time does milk go through the tubing and into the pump, or air from the
pump enter the nipple tunnel, breast cup, or collection bottle.  If
there were a hole in the diaphragm, there would be no vacuum, and no
milk released.
Therefore, there is no potential for contamination of this pump when
used with it's "hygeinkit".

That said, it is a relatively inexpensive machine, expected to last
about a year, which is it's warranty period.  I have sold many of them,
and moms have been very satisfied with it.  I would not recommend that
someone buy it used unless it were very cheap and they bought their own
new collection kit, because one never knows how much 'life' it has left
after the first owner's use.

PNS is a different situation.  The manufacturer does not recommend the
use of that machine by more than one person, though there is a brisk
market in used pns's as well.
--
Catherine Watson Genna, IBCLC  New York City  mailto:[log in to unmask]

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