The pistons in conventional syringes are relatively
large in diameter with a consequent large delivery volume per
millimeter of advancement.
Multi Dose Saline Driver Pump
Some delivery systems seek to overcome this by using a
micrometer type fine screw thread and calibrated thimble to advance
the large piston by very small distances such that calibrated
quantities of liquid are dispensed. Such systems work effectively, but
are expensive and difficult for the shoestring financed to make at
The device depicted here overcomes that problem by having
multiple pistons, each of small diameter so that any one of them can
be pushed individually into the syringe barrel by a calibrated
distance and thus deliver individual amounts of saline that in turn
displace semen in a capillary tube.
drawing has been started, but some components as yet are
not finalised (due for autumn 2002)... Email me if you want "up to
The pistons are intended to be needle roller bearings, if I
can track down some that are thin enough as well as long enough.
Bits and pieces can be obtained from many sources, the two
packets illustrated at right were purchased at a fishing tackle shop
and are respectively... pvc tubing that can be used to deliver saline
and silicone rubber sleeves that can be used to couple plastic and
They were not expensive, the pvc tube was £1.05 and the packet
of silicone sleeves was £0.75 (2001 prices).
The clear plastic tube
illustrated below came out of an inkjet printer that I
was dismantling for parts...
'that may come in useful'.
The right hand picture shows a surgical butterfly needle with tubing and
leur fitting adaptor that will fit on the nipple of our syringe barrel
Revised... 10 October 2001
Revised... 02 April 2002