Process Sensing Technologies

In-line transmitters that continuously report dew point or moisture content from a process line or compressed air system. Easidew is the named range, and Michell runs a formal Easidew Transmitter Exchange service.

Use it whenThis is the everyday choice: a permanent dew-point measurement on compressed air, a dryer outlet, or a process gas line, feeding a control system or an alarm. Reach for a transmitter rather than a portable when you need a continuous record or an automatic alarm on a wet dryer. The exchange programme is a good answer to 'what happens at calibration time' - the transmitter gets swapped rather than the measurement being lost.

Battery-powered handheld instruments for spot-checking dew point.

Use it whenUse these to survey a plant, prove out a dryer after service, settle an argument about which leg of a compressed air header is wet, or check a permanent transmitter in place. If a customer has one dew-point problem rather than an ongoing measurement need, a portable is the right first purchase.

Reference-grade instruments that measure dew point by cooling a mirror until condensation forms - a fundamental measurement rather than an inferred one. The site names the S8000 range, including a high-precision model.

Use it whenUse these when the measurement has to be the reference other instruments are checked against - a calibration lab, a metrology function, R and D, or a dispute over a supplier's gas quality. This is the top of the dew-point line, and it is specified because it is traceable, not because it is convenient.

Systems that generate a known humidity or dew point so instruments can be calibrated against it; the site names the ADG400 Advanced Dew Point Generator.

Use it whenUse this where a customer calibrates their own instruments in-house instead of shipping them out - typically a site with many hygrometers, or one whose quality system requires documented in-house verification. Michell also offers dew point and relative humidity calibration as a service, including on-site, which is the alternative to buying a generator.

Analyzer-class instruments for moisture in process gas and for hydrocarbon dew point, which is a different measurement from water dew point.

Use it whenReach for these on natural gas and petrochemical duty, where the question is often hydrocarbon dew point for pipeline or tariff compliance rather than water content. Do not substitute a water dew-point transmitter for a hydrocarbon dew point requirement - they are not the same measurement and the customer's contract will name one of them specifically.

Analyzers for water content in a liquid rather than in a gas.

Use it whenUse these for water in oil and similar liquid-phase moisture duty - transformer oil, lube oil, solvents and refrigerants are the usual reasons somebody asks. Different instrument class from the gas-phase range above, so confirm the fluid before quoting anything.

Combined humidity and temperature probes, which the site states are made by Rotronic for all applications including ATEX-rated potentially explosive gas and dust environments.

Use it whenStart here for any relative humidity measurement, and always specify temperature with it - the site makes the point that a small temperature change has a large effect on relative humidity, so humidity alone is often not a usable number. Ask about the area classification early; the ATEX-rated versions exist for a reason.

Transmitters with analogue and digital outputs. Named models include the HygroFlex HF5A and the HF3A, which the site presents as an HVAC transmitter, plus the TF5A temperature transmitter.

Use it whenUse a transmitter when the humidity value has to live permanently in a control system - a cleanroom, an environmental chamber, a warehouse, a data centre, an HVAC plant. The HF3A is the one aimed specifically at building HVAC duty, which is usually a different budget and a different specifier from process instrumentation.

Handheld humidity and temperature instruments, and data loggers that record over time.

Use it whenUse a handheld to investigate and a logger to prove. When a customer suspects a humidity problem but cannot say when it happens - overnight, on a shift change, during a washdown - a logger answers it and a walk-around instrument will not.

Instruments measuring water activity, also called equilibrium relative humidity, which the site describes as a key parameter in quality control of moisture-sensitive products. AwEasy is the named product.

Use it whenThis is a food and pharmaceutical quality-lab instrument, not a plant instrument. The reason a customer needs it is specific and regulatory: the site notes manufacturers must be able to show the FDA that a product's water activity has fallen far enough that bacteria can no longer grow. Water activity also drives texture, taste, colour, nutritional value and shelf life. If somebody asks for moisture content and means shelf-life risk, this is what they actually want.

A modular real-time environmental monitoring system: data loggers that record from Rotronic and third-party sensors and send them to a secure database, plus web-based software reachable from a PC, Mac, tablet or phone, with alarming, reporting and data analysis, calibration management, third-party integration, and digital hot-swap probes that carry their own calibration data and are recognised automatically by the software.

Use it whenUse RMS when the requirement is not a reading but a compliant record - hospitals, pharmacies, laboratories, food safety and transit monitoring, and any GxP environment needing audit trails and automated regulatory compliance. The hot-swap probe behaviour is the practical selling point: you change a probe without breaking the calibration record.

Analyzer platforms for oxygen in industrial process and gas streams.

Use it whenUse these where oxygen is the process variable or the safety variable - inert blanketing, glovebox and furnace atmospheres, gas generation and treatment, cryogenic air separation. Establish the required range first, because ppb, ppm and percent are effectively different instruments even though they are all called oxygen analyzers.

Analyzers for the very low end - oxygen as a trace contaminant rather than a bulk constituent.

Use it whenReach for these when oxygen is the impurity you are trying to exclude: gas purity verification, semiconductor and electronics, additive manufacturing, battery manufacture. If the customer talks in ppb, this is the group.

Analyzers listed for hazardous areas and described on the PST oxygen page as SIL capable.

Use it whenSpecify from this group when the analyzer sits in a classified area or forms part of a safety function. Get the area classification and any SIL requirement in writing up front - it narrows the model list immediately and retrofitting the rating later is not possible.

Battery-powered handheld oxygen analyzers.

Use it whenUse these for commissioning, purge verification, confined-space and spot checks, and for proving an installed analyzer. A purge check before a vessel entry or a restart is the classic reason a plant buys one.

The sensors themselves, including a replacement oxygen sensor range for industrial use, with a published gas compatibility reference.

Use it whenThis is the aftermarket, and it is worth real revenue - oxygen sensors are consumable and get replaced on a schedule. Use AII's gas compatibility reference before quoting a replacement, because the wrong sensor chemistry in the wrong background gas fails early. Note AII also lists medical and diving sensors, which are not our market.

Hydrogen sulphide analyzers, listed alongside the oxygen platforms on AII's site.

Use it whenUse these where H2S is the contaminant of interest, typically natural gas and petrochemical duty. Separate measurement from oxygen, so confirm which one the customer actually needs rather than assuming a combined instrument.