Analyical Scientific Instruments

ASI PrimeLine™ Replacement Pistons

It is hard to believe that sapphire, one of the hardest materials known to man, could ever be worn out or scratched by a soft material like Teflon or UHMW-PE. Unfortunately it does wear out. As the seal gets used, small particles of salt crystals, metal fragments, and other contaminants become embedded in the sealing surface of the seal. Over time these contaminants abrade the sapphire or ceramic plunger and form flat spots or longitudinal scratches. These wear spots will destroy any seal in a very short time.

It is extremely important to inspect the sapphire or ceramic plunger whenever you replace a seal. If there are any signs of scratches or glazed spots, replace the piston. Failure to do so will result in a shredded seal and a pump head full of seal wear material.

It is very difficult to see worn spots on a sapphire or ceramic piston. Hold the piston up to a bright light and inspect with a 10x magnifier or microscope. Any spot that appears dull, glazed, or scratched is a sure sign of a worn piston.

About ASI Pistons

Our sapphire and ceramic rods are 100% inspected to ensure that there are no inclusions or other surface defects that may cause premature seal failure. We apply the same rigorous standards for quality control and close manufacturing tolerances that we maintain for our check valves.

Please refer to the "Maintenance and Trouble Shooting Tips" on pistons for more information.

Piston QC Tests and Instrumentation

HIP Increases Density and Toughness

Piston diameter
Piston length
Geometry of ends
Roundness
Surface finish
Groove (if any)
Visual inspection
Digital micrometer
Caliper
Shadowgraph 20X
Talyrond
Talysurf
Shadowgraph 20X
Binocular 25X

Figure 49