Pumps, valves, probes, fittings, tubing and sensing components for precise sample preparation, reagent handling and instrument fluidics.
Solenoid Valves for Timed Shutoff and Fluidic Isolation
Application guide · Solenoid valves
A solenoid valve provides rapid on/off, isolation or two-path switching where the normal state and energization time are part of the safety design. Media compatibility, differential pressure, internal volume and coil duty must be evaluated together.
Engineering example: an analyzer that energizes a valve for 2 seconds every 10-second cycle has a 20% commanded duty before prime, alarms and service modes. A normally closed valve may still experience a much higher thermal duty during long wash or recovery sequences.[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
Source isolation
Normal state, upstream head and leak consequence
Stop siphon or unintended dosing
Wash pulse
Pulse duration, frequency and required flow
Coordinate valve opening with pump pressure
Vacuum/waste branch
Air-liquid exposure and fail-safe destination
Prevent crossflow and vessel overfill
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
Flow coefficient/path restriction
required flow at differential pressure
Check installed performance rather than orifice alone
Electrical duty
on-time ÷ total cycle plus fault modes
Controls coil heating
Internal volume
valve cavity + connectors
Adds response delay and wash demand
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
Confirm pressure state→Energize or release→Allow actuation delay→Perform liquid operation→Return to normal state→Check pressure or flow response
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
Valve clicks, no flow
Blocked path or insufficient differential
Use pressure/flow evidence, not sound alone
Intermittent leakage
Particle, seal damage or reverse pressure
Inspect filtration and installation direction
Coil overheats
Duty or voltage outside configuration
Review worst recovery and service states
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
State function
Flow and isolation in every normal/fault state
Matches the state table
Leakage
Maximum pressure and worst media
Within application limit
Thermal test
Longest energized sequence at worst ambient
No unacceptable heating or drift
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.
