Sample Conditioning for Online Wet-Chemistry Analysers
A practical guide to representative sampling, pressure, temperature, solids handling, reservoirs and filtration before a sample reaches the analyser.
Why the sample presented to the analyser matters
An online wet-chemistry analyser can only report on the sample that reaches it. Representative sampling and stable delivery are therefore part of the measurement system, not separate installation details.
01 / DEFINE THE JOB
Start with the measurement objective
Confirm the parameter, expected range and whether the result is for trending, alarms, compliance support or process control.
- Parameter and reporting basis
- Expected normal and upset ranges
- Required response time
02 / KNOW THE SAMPLE
Characterise the sample matrix
Record suspended solids, colour, temperature, pressure, flow variability, chemicals and any conditions that could affect transport or analysis.
- Normal operating conditions
- Known interferents
- Cleaning access
Present a stable sample
Choose a take-off point that remains representative across normal operation. Avoid stagnant legs, excessive transport delay, bubbles and uncontrolled pressure changes.
500 mL/min
Nominal sample flow
Confirm the required flow for the selected analyser configuration.
6 mm OD
Sample tubing
Keep runs practical and document the route and drain arrangement.
When filtration is appropriate
Filtration can protect the analytical path where solids would otherwise interfere, but the decision must reflect the measurement objective: removing material from the sample may also remove material you intend to measure.
For the detailed solids and sample-presentation questions, read our guide to planning filtration for an online water analyser.
3S-SF100
Self-cleaning filtration
Uses compressed-air backflushing with a user-set cleaning interval. The filter body uses 1-inch NPT process connections.
- Confirm solids loading
- Provide suitable compressed air
- Plan safe discharge
3S-SF50
Application-led conditioning
Select conditioning around the process, parameter and sample behaviour, not simply as a default accessory.
- Check representative recovery
- Verify transport time
- Retain maintenance access
Conditioning decisions to document
A clear installation record makes commissioning faster and helps operators understand what the analyser result represents.
01–03
Sample source
Record the take-off point, expected flow and pressure, and the distance to the analyser.
- Representative sample point
- Flow and pressure
- Line length and elevation
04–06
Sample behaviour
Document temperature, solids, bubbles and any settling or reaction that may occur during transport.
- 5–45°C operating environment
- Solids and turbidity
- Air entrainment
07–09
Services and discharge
Confirm drain routing, reservoir or fast-loop arrangements, filtration and cleaning services.
- Free-draining waste route
- Reservoir or bypass loop
- Filtration and compressed air
NEXT STEP
Review before installation
PMA can review the parameter, sample matrix, process conditions and proposed sample arrangement before final specification.
- Choosing an online water analyser
- 3S product overview
- Applications overview
Plan the sample system with the analyser
Share the parameter, range, sample conditions, solids loading and proposed take-off point so PMA can review the arrangement.