Purge and Trap analysis is used to detect volatile organic compounds (VOCs) in water, wastewater, soils and sludges. The Purge and Trap technique removes VOCs from a sample matrix
by passing an inert gas, such as helium or nitrogen through the matrix, to purge/remove the VOC, where it is collected in a sorbent trap.
Once isolated, VOCs are desorbed from the trap through a heating process, which removes an analyte that is needed for chromatography sample analysis. The analyte is transferred to
a GC column in an automated fashion, which ensures minimal sample handling and reproducible results.
The automated movement of these samples is driven by a linear actuator. The motorized mechanism drives the needle to pierce the septum of the sample vial.
Application Challenges (Pros & Cons):
• Consistency & accuracy – to improve sample quality
• Small footprint – to save lab counter space
• Simplicity – for easy control.
Typical Current Motion Solutions:
• Stepper actuator or rotary + lead screw
• Ball screw module
HKP Actuators and Lead Screws are preferred for these applications, for the following reasons.
Linear Stepper Actuators:
Haydon Kerk Motion Solutions’ line of hybrid stepper motor linear actuators drive a rotor nut on a stainless steel precision acme lead screw. This patented interface reduces tolerances and noise while increasing efficiency. Available in captive, non-captive and external linear configurations, these actuators are specifically designed for high performance and exceptional endurance in a small package.
Lead Screws:
Kerk Lead Screw Assemblies are modified acme thread forms that are optimized for performance. They are available in a broad range of lead screw diameters, leads and nut styles.
Self-adjusting, maintenance-free and requiring no lubrication, Kerk lead screws provide maximum accuracy, high reliability, quiet operation and low costs.