What do these products do in this instrument?
Syringe pumps: fixed-needle liquid-displacement drive
Organize aspiration and dispensing in fixed-needle architectures using syringe-driven liquid displacement, coordinated with system liquid, valve position and needle motion. Confirm actual sample-contact areas and internal/external needle washing separately.
HLD and HMD organize aspiration/dispensing paths with rotary and solenoid valves respectively. Capacity budgets include useful volume, holding stages and replenishment points; valve states and pump actions together create each delivery.
Organize syringe metering around aspiration, holding and dispensing
Syringe drives use controlled displacement for aspiration, holding and dispensing. With direct contact, source liquid enters the metering chamber; with system-liquid drive, sample can remain at the probe tip or a designated tube segment. Define wetted coverage before capacity, cleaning and replenishment. For repeated dispensing, track current inventory, delivered volume and next replenishment time.
Map valve connections to every action
Check port connections, opening/closing sequence and power-off state separately for rotary- and solenoid-valve configurations. Changing source does not automatically remove old liquid from the chamber or shared tubing. Plan flushing for formulation and residue requirements, then evaluate the first dose after switching and dose-to-dose variation.
Translate actual branch conditions into configuration requirements
| Condition | To confirm |
|---|---|
| Stored volume and timing | Define volume per operation, consecutive dispensing count, holding time and permitted replenishment window. |
| Valve positions and destinations | Provide a source, receiver and waste port diagram with open/closed and power-off states. |
| Liquid changes and first dose | Check shared residue, priming destination and actual received volume after standby or source changes. |
| Operation | Specific operating conditions |
|---|---|
| Multiple dispenses from one aspiration | Dose per operation, total cycle volume, replenishment/bottle-change interval, backpressure and receiving geometry |
Compare product configurations by the roles on this page
| Product | Configuration option | Conditions to verify |
|---|---|---|
| HLD rotary-valve syringe pump | Aspiration, holding and dispensing with a rotary valve | Check source/outlet valve positions, capacity budget and replenishment timing |
| HMD solenoid-valve syringe pump | Metered aspiration and dispensing with solenoid valves | Check open/closed and power-off states, working volume and replenishment cycle |
Related operations and architecture comparisons
Multiple dispenses from one aspiration
Nominal capacity minus retained volume determines the usable dispensing range. Record every dose, comparing first, middle and last doses and the first dose after replenishment, rather than measuring the average alone.
Confirm product roles in actual operation
| Operation | Measurements and observations | Priority checks |
|---|---|---|
| Multiple dispenses from one aspiration | Use actual media to check first, middle and last doses and delivery after bottle changes; confirm received volume and timing rather than substituting commanded steps for volume | Empty sources, bubbles, nozzle droplets and backpressure changes affect first or last doses |
Measure delivery with actual liquids, tips and well positions, including idle periods, refills and multiple dispensing.
For repeated dispensing from one chamber, is checking total volume enough?
Measure each received dose, especially the first and last. Even when total volume is near target, individual errors may differ. Relate replenishment, valve switching and receiving actions to each result.
Nominal capacity and volume per step do not establish the minimum reliable pipetting volume. Disposable tips and reusable probes require different cleaning strategies.