By and large, the small precision plunger pump is one of the most versatile and demanded for high reproducibility and accuracy. Downsizing is the needs
of the times, and the pump modules for systems cannot be an exception. Increasingly demanded are lesser and lesser volume of reagents and samples
as well as high throughput and multi-function in the system. As the fluidic flow volumes get smaller, all of the mechanisms of the pump will need to
be smaller, including micro-scale dead volumes, and high-precision machining is executed to provide unparalleled accuracy and high reproducibility.
The plunger material is available from zirconia, sapphire, or stainless
steel. The use of stainless steel plunger may sound strange in consideration
of its chemical compositions. However, the stainless steel is a material
much more ideally suitable for high precision machining, and its drawback
of containing some negative chemical compositions is offset with chromium
nitride (CrN) treatment on the plunger surface. The CrN treated stainless
steel plunger provides higher abrasion resistance, and chemical inertness
equivalent to ceramic in addition to dimensional accuracy and surface smoothness,
while its cost is much lower than sapphire.