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.
Define the flow-time profile, allowable interruption and run duration before calculating total volume. For extended operation with the actual medium, evaluate bottle changes, priming, filter pressure drop and backflow protection. Closed-loop process control also requires relevant process sensors.
Common product roles and application guides
| Product category | Role in this instrument |
|---|---|
| Syringe pump | Intermittent or alternating supply |
| Valveless metering pumps | Suitable metering for extended feeding runs |
| Fluidic valves | Formulation and refill-source selection; tubing-branch shutoff and maintenance |
| Bubble and pressure detection | Signals for controller logging of abnormal feed intervals |
| Tubing connections and protection | Feed-branch backflow limitation; extended-run feed paths and loads |
Operating requirements differ by step
| Stage | Task category | Operating conditions to define |
|---|---|---|
| Supply mode: include refill interruptions in continuity assessment | Continuous-supply inputs | Actual flow, cumulative volume, allowable interruptions, backpressure, refills and operating duration |
| Medium changeover: confirm arrival of the new formulation | Valve-path requirements | All ports, valve states, pressures in each state, shared volume and flushing volume |
| Path protection: check added resistance | Load and backflow protection | Check-valve cracking pressure, reverse leakage, filter pressure drop, actual load and maintenance state |
| Feedback and records: retain actual anomaly intervals | Inputs for fault detection | Specific sensor configuration, location, liquid/tubing, sampling rate, threshold and time window |
Supply mode: include refill interruptions in continuity assessment
Measure cycle output and pauses under actual load. Correct cumulative volume does not ensure that every interval meets its flow requirement; define acceptance criteria separately.
Medium changeover: confirm arrival of the new formulation
Bottle changes, priming and switching are different events. Calculate shared volume, then verify arrival time and initial composition to prevent cleaning residue entering the culture.
Path protection: check added resistance
Check-valve opening pressure, filter pressure drop and backpressure affect the pump operating point. Backflow prevention and sterile isolation require separate validation.
Feedback and records: retain actual anomaly intervals
Pressure or bubble modules report fluid-path conditions. Control of pH and other process variables needs corresponding sensors and algorithms. Whether to compensate feeding after recovery is determined by the process program.
Explore configurations through product application guides
Validate the complete cycle through application results
Record output across the run, replenishment interruptions, first flow after bottle changes and reactor volume balance.
| Step to validate | Measurements or observations | Priority troubleshooting checks |
|---|---|---|
| Supply mode: include refill interruptions in continuity assessment | Measure operating-flow trends and cumulative volume, including refill interruptions. Evaluate proportioning, process or analytical results according to the task. | An empty source, bubbles, slip, pressure changes or resetting can disturb continuous output. |
| Medium changeover: confirm arrival of the new formulation | Check unintended connections, leakage, backflow and post-switching residue in each state; measure flushing volume and arrival delay through the complete path | Misalignment, shared-segment residue or abnormal switching pressure may affect the next task |
| Path protection: check added resistance | Measure opening load, normal flow, reverse leakage and recovery after replacement; validate sterile boundaries separately. | Excessive opening pressure, reverse leakage or filter blockage can disturb feeding. |
| Feedback and records: retain actual anomaly intervals | 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 |
Refilling or resetting a single syringe can interrupt supply. Continuous-operation capability and aseptic isolation both require system validation.
Common selection and recovery questions
Does correct total feed volume establish acceptable continuous supply?
Also check flow and variation in each time window, refill or bottle-change pauses, and the initial output after restart. Validate continuity and cumulative volume separately with the actual medium and load.
Can a feed deficit be made up in one addition after a flow stop?
First preserve abnormal time windows and actual delivered volume. Apply process-permitted compensation and recovery rates. Cumulative shortfall alone cannot determine the restart action.