Pumps, valves, probes, fittings, tubing and sensing components for precise sample preparation, reagent handling and instrument fluidics.
Multiport Rotary Valves for Analytical Flow Selection
Application guide · Multiport selection
A multiport rotary valve lets one metering channel select several samples, reagents, standards, cleaners or destinations. The usable design is defined by the complete state table and the liquid left in the common passage after every switch, not by port count alone.
Engineering example: if a shared passage holds 20 μL and a 100 μL dose is taken immediately after switching from a concentrated standard to a blank, one common-path volume equals 20% of the next dose. The actual contamination is application-specific, but the calculation shows why purge volume must be assigned before the valve is selected.[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
Reagent/source selection
Number of sources, shared passages and incompatible liquids
Map every source-to-pump state and cleaning transition
Destination selection
Reaction cup, detector, waste and bypass states
Prevent unintended discharge during switching
Calibration sequence
Blank-to-high and high-to-low order
Budget purge from the most demanding transition
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
Required ports
active sources + wash/waste/service positions
Include future and safe states explicitly
Purge volume
common swept volume × qualified exchanges
Sets liquid use and transition time
Switching window
actuation + settle + pressure equalization
Must fit the analytical cycle
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
Equalize or stop flow→Move to defined port→Confirm valve state→Purge shared path→Meter valid liquid→Wash or return to safe state
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
Wrong liquid reaches receiver
Incorrect state table or position feedback
Block result and compare command with physical position
High-to-low carryover
Shared volume not fully exchanged
Measure common-path volume and qualify purge
Pressure spike at switch
Switching against trapped pressure
Add equalization or change sequence
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
Port identity
Tracer through every commanded state
Only intended source reaches each destination
Carryover
Worst high-to-blank transition
Meets method-specific limit
Leak/isolation
Closed and adjacent ports at maximum operating pressure
No unacceptable cross-port transfer
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.
