Where sample metering fits in the instrument
Confirm the condition of water entering the analytical unit and the pretreatment permitted by the method. Configure metering for actual sample volume, particles and matrix. See environmental monitoring for field-transfer distance, delay and maintenance.
Include particles, salinity and matrix variation in the water-sample requirements. Validate metering at the analytical unit's receiver, separately from field-sample refresh time.
Product responsibilities in this operation
Piston drive creates controlled displacement, working with valve positions and the receiver to deliver this volume. Check working stroke and actual received volume separately.
For this water analysis unit task, confirm actual sample volume, remaining source-vessel volume, needle-opening height, aspiration/dispensing speeds and system liquid.
Organize the sequence by actual architecture
- Confirm the water sample's source, renewal time and method-permitted pretreatment before it enters the analyzer. Define target constituents, particles and matrix range.
- For the specified wetted architecture, check the piston metering path, effective liquid column and source-valve position, then aspirate the required sample volume.
- Deliver the water sample to the method-defined reaction or receiving position. Measure actual volume and record anomalies caused by air aspiration, residue or particles.
- Check the first sample after source changes, washing and standby before continuing to reaction steps. Validate representativeness and renewal time in long-distance upstream sampling separately.
Define operating conditions for this task
| To define | Details |
|---|---|
| Actual operating conditions | Actual sample volume, remaining source volume, probe-tip height, aspiration/dispensing speed and system liquid |
| Acceptance target | Measure the water sample at the analytical unit receiver using the permitted pretreatment and actual particle, salt and matrix conditions. Check the first sample after source changes, washing and standby alongside routine volumes. |
| Fault localization | Air entry, particles, leaks or retained previous sample can change the volume or composition delivered to the analytical unit. A renewed upstream source does not prove that the internal metering path contains the new sample. |
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 |
Validate operation results at the receiver
Measure the water sample at the analytical unit receiver using the permitted pretreatment and actual particle, salt and matrix conditions. Check the first sample after source changes, washing and standby alongside routine volumes.
Assess blanks and method response after the sample arrives. Record the upstream renewal time separately so accurate internal metering is not mistaken for representative field sampling.
Locate abnormalities and restore the next operation
Air entry, particles, leaks or retained previous sample can change the volume or composition delivered to the analytical unit. A renewed upstream source does not prove that the internal metering path contains the new sample.
Hold the affected analysis and confirm source identity, renewal state and any sample already delivered. Restore the effective liquid column and shared-path update, then verify the first receiver volume and method blank before restarting the reaction sequence.
Validate field representativeness and internal metering separately. Filtration intended to protect components must still meet method requirements.