What do these products do in this instrument?
Piston pumps: metered sample and reagent delivery to reaction cuvettes
Drive specified volumes into reaction cuvettes in suitable discrete-metering branches. Coordinate probe movement and detection sequences, recording motor action, liquid leaving the probe and actual arrival separately.
EA, SM and TM provide options for comparing capacity, wetted configurations and installation space. Verify actual doses from working stroke and the complete wetted path; check system-liquid drive and direct sample contact with the pump head separately.
Distinguish piston displacement from actual received volume
Piston pumps use controlled displacement for discrete aspiration and dispensing. Sample may enter the head directly or remain at the probe tip while system liquid transmits displacement; wetted coverage, priming and cleaning differ. Map aspiration, holding, dispensing and replenishment paths first, then relate stroke to probe-tip delivery.
Further technical reading
Combine metering, valve positions and container actions into a complete cycle
Delivery requires coordination of metering drive, source switching and receiving-end actions. Usable capacity must cover working volume and other cycle displacements, with replenishment in permitted windows. Check tip droplets, bubbles and shared residual liquid through the complete path; remeasure received volume after changing pump heads, tubing lengths or interfaces.
Translate actual branch conditions into configuration requirements
| Condition | To confirm |
|---|---|
| Working stroke | Use assay-specified sample and reagent volumes, with any priming and replenishment fitted into the permitted addition sequence. |
| Liquid contact and pressure | Identify the sample-contact or system-liquid interface, probe outlet and reaction-cuvette geometry for each pressure and valve state. |
| Delivery and recovery | Measure received volume and liquid-arrival time at the reaction position, including idle recovery and the first dose after washing. |
| Operation | Specific operating conditions |
|---|---|
| Assay-specified sample delivery | Assay-permitted sample and dose, probe/cuvette position, system-liquid interface where present, actual liquid-arrival time and the reaction trigger sequence |
Compare product configurations by the roles on this page
| Product | Configuration option | Conditions to verify |
|---|---|---|
| EA standard piston pump | Finite-stroke metering | Compare configurations by routine dose, total cycle displacement and wetted materials |
| SM miniature piston pump | Discrete metering in compact installations | Check installation space first, then validate working doses and actual accuracy |
| TM ultra-miniature piston pump | Discrete metering in limited space | Check installation space and configuration before measuring actual delivery; an ultra-miniature design does not imply a smaller reliable dose |
Explore specific operating and validation tasks
Assay-specified sample delivery
Small sample doses require checks of tip droplets, cuvette-wall contact and the system-liquid interface. Measure at the actual reaction location to relate volume to results.
Confirm product roles in actual operation
| Operation | Measurements and observations | Priority checks |
|---|---|---|
| Assay-specified sample delivery | Measure sample volume at the reaction cuvette and distinguish motor completion, liquid leaving the probe and actual arrival. Assess timing and post-wash residue with the assay. | Air aspiration, leakage, probe droplets, wall contact or delayed arrival may alter volume or reaction timing; a completed motion does not confirm a valid reaction start. |
Evaluate received volume, liquid arrival and trigger timing together at the reaction site. Use the assay to assess first-dose recovery and the effect of any wash-liquid residue.
Are piston pumps of equal capacity directly interchangeable?
Also check wetted materials, interfaces, mounting, drive and pressure conditions. After replacement, recheck delivery, cleaning and first-dose recovery with the original sequence and actual liquids. Capacity is only one comparison criterion.
Pump or valve response time is not the reagent-contact or instrument measurement-start time.