What do these products do in this instrument?
Piston Pumps: Sample and Reagent Metering Inside the Analytical Unit
Deliver specified sample or reagent volumes in metering branches downstream of water-sample receipt, coordinated with reaction vessels and measurement programs. Confirm particle and matrix changes against sample conditions permitted by the method.
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 displacement meters water samples or reagents in the analytical unit. Identify which liquid contacts the pump head and whether the installed design uses direct sample contact or a system-liquid interface. Map aspiration, delivery and refill states, then measure the volume reaching the analytical vessel.
Combine metering, valve positions and container actions into a complete cycle
Coordinate source selection, metering stroke and the receiving reaction step. Include path renewal and refilling in the cycle budget, with defined destinations for displaced sample and wash liquid. After changing the pump, tubing or fittings, recheck received volume and actual arrival against the measurement sequence.
Translate actual branch conditions into configuration requirements
| Condition | To confirm |
|---|---|
| Working stroke | Budget the water-sample and reagent doses, shared-path renewal and refill displacement for the actual in-cabinet analysis cycle. |
| Liquid contact and pressure | Specify the method-permitted water matrix and actual metering path, including particle conditions, wetted materials and pressures at each valve state. |
| Delivery and recovery | Measure volume received at the analytical vessel and actual reagent arrival; assess blanks, method recovery and the first reaction after washing or maintenance. |
| Operation | Specific operating conditions |
|---|---|
| Sample metering | Method-permitted water matrix, particle and salt conditions, sample dose, actual intake and receiving geometry, shared volume and sample-renewal state inside the analyzer |
| Metered reagent addition and reaction timing | Reagent formulation and working dose, addition order, actual arrival delay, mixing interval and the method measurement trigger |
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
Sample metering
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.
Metered reagent addition and reaction timing
Adding the same volume at different times can change a reaction. Record each actual delivery, mixing, temperature control and measurement time, then assess the reaction result.
Confirm product roles in actual operation
| Operation | Measurements and observations | Priority checks |
|---|---|---|
| Sample metering | Measure sample volume at the analytical receiver using representative permitted water matrices. Assess sample changes, blanks and method recovery, separately from field-line sample transit and refresh. | Particles, settling, air entry, shared-path residue or incomplete sample renewal can change the delivered aliquot or its composition. Inspect the actual intake and metering path rather than assuming a probe or system-liquid design. |
| Metered reagent addition and reaction timing | Measure reagent receipt and arrival time at the reaction vessel, then assess the complete reaction, blank and recovery according to the method. | Residual wash liquid, delayed arrival, outlet droplets or inadequate mixing can change reaction initiation or composition even when the commanded volume is correct. |
Assess sample and reagent volumes, actual arrival, blanks and recovery in the water-analysis method. Where filtration is used, verify the fraction measured; field-sample transport remains a separate task.
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.
Validate field representativeness and internal metering separately. Filtration intended to protect components must still meet method requirements.