Pumps, valves, probes, fittings, tubing and sensing components for precise sample preparation, reagent handling and instrument fluidics.
Pressure and Blockage Monitoring in Analytical Fluid Paths
Application guide · Pressure monitoring
Inline pressure monitoring converts a pump cycle into a diagnostic waveform. A useful implementation records pressure against motion, valve state and time so that blockage, leakage, empty source and normal viscosity changes can be separated.
Engineering example: if a normal aspiration reaches −20 kPa and a blocked probe reaches −60 kPa, a fixed threshold may work for one liquid. A viscous sample that normally reaches −45 kPa needs a different baseline or waveform rule; one limit cannot represent every method.[1][2]
01Define the liquid, receiver and complete duty before selecting the component
Translate the analytical task into an engineering duty
Use case
Inputs to define
Decision supported
Aspiration supervision
Expected vacuum profile by liquid and speed
Detect clot, bottom seal or empty source
Dispense supervision
Expected positive pressure and outlet state
Detect closed valve or restricted tip
Filter/service trending
Pressure change over days or cycles
Schedule maintenance before functional failure
02Calculate the working point and the margin the instrument really needs
Calculations to complete before prototype selection
Quantity
How to define it
Why it matters
Pressure range
normal extrema + fault challenge + margin
Avoid saturation while retaining resolution
Sample rate
shortest meaningful transient
Capture valve and pump events
Added volume/resistance
sensor and adapters
Ensure measurement does not change the channel materially
Use minimum, routine and maximum conditions rather than one nominal point. Include the first cycle after priming or idle, the lowest source level, the highest expected restriction and the actual receiving geometry. A nominal capacity, free-flow value or theoretical command increment is not an acceptance result.
03Map the task to a FOREACH configuration and the rest of the fluid path
04Program the full liquid cycle, including prime, wash and recovery
Record normal waveform→Open command-specific window→Compare peak, area and recovery→Classify likely fault→Perform controlled retry or stop→Log trace for service
A complete method cycle is more than the active delivery step
The exact physical order and parallel actions depend on the instrument. Retain each state in the control and verification plan.
Record valve states, motion, dwell, sensor windows and rejected recovery cycles. This makes throughput and liquid consumption auditable and prevents a fast component movement from being reported as the complete analyzer cycle.
05Design abnormal-state diagnosis before the fault occurs
Observed result, likely mechanism and useful next action
Observed condition
Likely mechanism
Engineering response
High vacuum
Clog, bottom contact or high viscosity
Use context before deciding recovery
Low pressure response
Leak, empty source or disconnected line
Check bubble/source state
Slow return to baseline
Compliance, trapped gas or valve leakage
Inspect line and valve state
The controller should distinguish a recoverable event from a result-invalidating event. A retry is useful only after the original cause has been removed and the liquid path has returned to a verified state.
06Accept performance where the liquid is actually used
Minimum qualification plan for the integrated channel
Result
Where or how to measure
Acceptance question
Normal envelope
Liquids, speeds and temperatures in scope
Contains accepted cycles without excessive false rejects
Fault separation
Known clog, leak and empty-source challenges
Required faults trigger correct action
Long-term trend
Filter loading and component aging
Service threshold occurs before result failure
Test the exact liquid and complete wetted path at minimum, routine and maximum conditions.
Separate first-cycle, steady-state and post-idle results; do not average away recovery behavior.
Challenge the relevant fault and confirm the controller prevents an invalid result from being accepted.
Retain the configuration, software sequence, consumables and receiving-position result together as the qualification record.
