Pumps, valves, probes, fittings, tubing and sensing components for precise sample preparation, reagent handling and instrument fluidics.
Low-Dead-Volume Fittings and Fluidic Assembly
Application guide · Fittings
A fitting must seal the specified tube to the component port without creating an unswept pocket or bore step that traps the previous liquid. Thread name alone is insufficient: tube OD/ID, ferrule, pilot depth, port geometry and installation procedure define the connection.
Engineering example: a 1 mm-long annular gap around a 0.5 mm-ID flow path can retain liquid even when its absolute volume is small. In a 5 μL sample channel, sub-microlitre connection pockets can still be a material fraction of the dose and require direct carryover testing.[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
Permanent low-volume joint
Tube dimensions and matched bore
Minimize unswept volume and reassembly
Service disconnect
Connection cycles and operator access
Control insertion depth and replacement consistency
High-pressure connection
Port standard, pressure and tubing material
Use the exact compatible nut/ferrule system
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
Bore match
upstream ID, fitting bore and downstream ID
Avoid steps and cavities
Engagement
port depth and tube insertion
Ensures seal at the intended surface
Service load
cycles, torque and replacement interval
Prevents damage and variable assembly
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
Identify exact port→Select matching tube and fitting→Prepare square tube end→Insert to defined stop→Tighten by qualified method→Leak and carryover test after 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
Leak after reassembly
Damaged ferrule or incomplete insertion
Replace controlled parts and retrain method
Carryover at joint
Unswept gap or bore mismatch
Inspect geometry and use tracer
Tube pull-out
Wrong ferrule/OD or pressure load
Correct component family and retention
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
Leak integrity
Maximum operating and transient pressure
No external or cross-port leak
Internal volume
Drawing or measured tracer response
Fits carryover/dispersion budget
Service repeatability
Multiple qualified reconnections
Performance remains within limit
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.
