Locate the task in the fluid path first
Arrows indicate task relationships, not that every component is connected in series in one tube. Check valve positions, pump wetted boundaries and operating states for each branch.
Distinguish single additions, periodic dosing and continuous supply, and specify the actual medium and temperature. For cell transfer, also record concentration, aggregation, minimum bore and residence time. Compare candidate configurations using cell results before and after the actual process.
Common product roles and application guides
| Product category | Role in this instrument |
|---|---|
| Syringe pump | Periodic replenishment and discrete transfers |
| Valveless metering pumps | Repeated or continuous medium delivery in suitable configurations |
| Diaphragm pump | Auxiliary culture-medium supply and washing |
| Tubing pinch-off solutions | Flexible-tube branch isolation |
| Bubble and pressure detection | Detecting supply interruptions and abnormal loads |
| Tubing and fittings | Connect culture vessels to liquid sources |
Operating requirements differ by step
| Stage | Task category | Operating conditions to define |
|---|---|---|
| Medium replenishment: cover the complete operating cycle | Feed mode and cumulative material balance | Discrete or continuous feeding mode, time profile, medium, load, cumulative volume and permissible interruption |
| Suspension transfer: assess both liquid volume and cell condition | Sampling conditions | Cell density, flow rate/pressure differential, bore size, residence time and condition before transfer |
| Condition monitoring: define flow-stop and recovery criteria | Inputs for fault detection | Specific sensor configuration, location, liquid/tubing, sampling rate, threshold and time window |
Medium replenishment: cover the complete operating cycle
Include bottle changes, priming and the first delivery after flow stops in the replenishment program. A short water test does not establish material compatibility or medium-delivery performance over an extended run.
Suspension transfer: assess both liquid volume and cell condition
A smaller bore, higher pressure differential or changed local velocity alters the conditions experienced by cells. Compare viability, recovery and aggregation before and after transfer to establish an acceptable operating range.
Condition monitoring: define flow-stop and recovery criteria
Pressure and bubble signals can help identify supply anomalies. Culture condition requires relevant biological process measurements, and actual cumulative volume in the culture vessel still needs confirmation after supply resumes.
Explore configurations through product application guides
Validate the complete cycle through application results
Compare viability, recovery and cell condition before and after transfer, and validate the required contamination controls.
| Step to validate | Measurements or observations | Priority troubleshooting checks |
|---|---|---|
| Medium replenishment: cover the complete operating cycle | Measure pulse doses or flow over defined time windows separately, then reconcile cumulative material, bottle changes and restarts. | An empty source, bubbles, refill interruptions or repeated control states may alter actual feed delivery. |
| Suspension transfer: assess both liquid volume and cell condition | Compare cell viability, recovery and required cell attributes before and after transfer; verify sealing and contamination control through the complete flow path. | Air aspiration, clots/particles, probe contact with a wall or leakage alter actual delivery |
| Condition monitoring: define flow-stop and recovery criteria | Measure fault detection, false alarms and end-to-end response separately; cover baseline changes with liquid, speed and operating conditions | Normal air segments, viscosity changes and sampling delays may be misclassified |
Low shear and sterility are validation objectives for the complete flow path. Neither a diaphragm pump nor a pinch valve alone establishes them.
Common selection and recovery questions
Does validated medium delivery establish suitability for cell transfer?
For cell suspensions, compare recovery, viability and aggregation before and after transfer at the actual bore, pressure differential and residence time. Medium-delivery tests do not replace this assessment.
What should be checked before restarting supply after a flow interruption?
Check cumulative volume in the vessel, the liquid column and bottle-change status, then examine initial delivery after recovery. Experimental requirements determine the permissible interruption and whether culture can continue.