What do these products do in this instrument?
Syringe pumps: pulsed feeding and discrete sampling
Move medium, additives or samples in branches requiring specified individual volumes, coordinated with source and receiver. Define usable stroke and refill timing, and include sampling and discard in the process-volume balance.
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 |
|---|---|
| Sampling | Analyte, sampling interval, renewal of stagnant sections, discard-volume budget and permitted pretreatment |
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 |
Explore specific operating and validation tasks
Sampling
Renewing stagnant sections consumes liquid; small systems especially need a volume budget. Use paired sample analysis and reactor-volume records together to assess sampling.
Confirm product roles in actual operation
| Operation | Measurements and observations | Priority checks |
|---|---|---|
| Sampling | Measure renewal time at the analytical or receiving interface and assess target representativeness using paired samples | Old-sample mixing, settling, adsorption or insufficient renewal time can make the sample unrepresentative of its source. |
Check cumulative feeding, sampling representativeness, volume balance and recovery during long runs.
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.
Bubble and pressure signals describe fluid-path conditions; they do not directly measure pH, dissolved oxygen or growth. Validate the complete aseptic boundary separately.