Pumps, valves, probes, fittings, tubing and sensing components for precise sample preparation, reagent handling and instrument fluidics.
Valveless Pumps for Carrier Liquid and Flow-Cell Supply
Application guide · Continuous supply
Continuous carrier or flow-cell supply is chosen from the installed flow range and the detector's tolerance for pulsation, bubbles and concentration transition. Rotational displacement and speed provide an initial flow estimate, but the useful flow must be measured through the actual line, cell and outlet condition.
Engineering example: a 100 μL/rev setting at 50 rpm gives a theoretical 5 mL/min and at 100 rpm gives 10 mL/min. These are displacement calculations; slip, pressure and fluid properties determine the installed result.[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
Carrier stream
Required flow range and composition
Maintain stable transport through the measurement window
Flow-cell supply
Cell volume, acceptable pressure and baseline sensitivity
Evaluate pulsation at detector bandwidth
Rinse/transition
Line volume and target concentration recovery
Size exchange time separately from steady flow
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
Theoretical flow
μL/rev × rpm ÷ 1000
Starting point for speed selection
Exchange time
system volume ÷ installed flow
Add mixing/tailing allowance
Pressure margin
line + valve + filter + cell losses
Check against pump curve and connections
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
Prime to waste→Ramp to target speed→Wait for concentration transition→Open valid detector window→Monitor pressure/bubbles→Flush and stop without backflow
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
Periodic detector ripple
Pump pulsation or bubble passage
Correlate signal with motor phase and add suitable damping
Slow concentration change
Excess path volume or mixing
Reduce volume or increase controlled flush
Flow decays
Restriction, low inlet level or wear
Trend pressure and measured outlet flow
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
Installed flow
Measure at minimum/routine/maximum speed
Report with liquid and pressure
Detector stability
Baseline or tracer signal during valid window
Meets method-specific ripple/noise limit
Transition
Time and volume to reach target concentration
Supports cycle-time requirement
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.
