ENGINEERING DECISIONS
Engineering logic for this condition
Build a service description from process records. Include all constituents, concentration ranges, water content, contaminants, phase, aeration and credible start-up, shutdown or cleaning mixtures. Corrosion mechanisms can change with temperature, velocity, crevices, galvanic couples and trace impurities. Identify erosion, permeation, stress corrosion, coating, crystallisation and toxicity as separate risks. A generic compatibility chart can support screening but cannot establish service life for an undisclosed process.
Review every part exposed to the process, not only the primary diaphragm or probe. Connections, welds, electrodes, liners, gaskets, O-rings, isolation valves, flush rings and fill fluids may set the boundary. A remote or flush diaphragm can isolate a narrow pressure passage, while lined or non-contact principles may reduce certain exposures, but each introduces new limits. Pressure-temperature ratings, vacuum, cleaning and mechanical damage remain part of the selection.
Plan containment and maintenance before finalising the sensor. State whether the point needs double isolation, flushing, purge, leak detection, remote mounting or safe removal. Define the required material declarations, inspection records, drawings and certificates for the specific configuration. The proposal should identify each wetted material and unresolved compatibility assumption. Process-owner approval is required where mixture data or corrosion experience remains incomplete.
Selection inputs and technical route
- Chemical definition
- Constituents, concentration range, impurities, phase, safety-data reference and mixtures during cleaning or changeover.
- Exposure conditions
- Normal and upset pressure-temperature envelope, velocity, aeration, dwell time, cycling and vacuum.
- Damage mechanisms
- General or local corrosion, erosion, permeation, swelling, stress cracking, coating and crystallisation.
- Complete wetted boundary
- Sensor, connection, weld, gasket, liner, electrode, probe, seal, valve and accessory materials.
- Containment and records
- Isolation, flushing, leak control, removal method and configuration-specific material and inspection evidence.
Applications for engineering review
- Acid, alkali or chemical storage where concentration and temperature ranges are known and every wetted material is reviewed.
- Dosing and transfer systems where low flow, pulsation, containment, flushing and maintenance access are defined.
- Corrosive vapour or reactor service where condensation, vacuum, coatings and cleaning mixtures are included in the assessment.
Limitations and confirmation points
- No generic alloy or polymer is compatible with every concentration, impurity and temperature, and this page does not predict service life.
- Unknown mixtures, reactive media or toxic containment duties may require laboratory, corrosion-specialist or process-owner assessment.
APPLICATION RFQ
Information to send for configuration review
- Chemical names and concentration ranges
- Impurities, water content and process phase
- Normal and upset pressure-temperature envelope
- Cleaning, flushing and changeover mixtures
- Velocity, solids, coating and crystallisation risks
- Required wetted materials and prohibited materials
- Connection, gasket, lining and seal details
- Containment, isolation and safe-removal method
- Output, environment and area classification
- Quantity and required material or inspection records
PRODUCT FAMILIES
Related product categories
APPLICATION FAQ
Frequently asked questions
How should material compatibility be checked for a corrosive medium?
List every constituent, concentration range, impurity, normal and maximum temperature, pressure, cleaning chemical and exposure duration. Review all wetted parts, including small gaskets, electrodes, liners, welds and fill fluids. Published tables and past service can inform a preliminary shortlist, but the process owner must evaluate the actual mixture and failure consequences. Record the chosen materials and any assumptions against the exact model, option set and connection.
Does a diaphragm seal solve every corrosive pressure application?
No. A seal can isolate the transmitter from the process and offer a selected diaphragm or coating, but its connection, gasket, diaphragm, fill fluid and any flushing accessory still require compatibility review. Vacuum, temperature, capillary routing and pressure range can affect performance. Crystallising or coating media may also obstruct the process face. Treat the seal and transmitter as one assembly and request its configuration-specific drawing, limits and material records.
Which process changes can invalidate a previous corrosion selection?
A higher concentration or temperature, new impurity, oxygen ingress, cleaning chemical, longer stagnant period, greater velocity or a material substitution can change the corrosion mechanism. A change from liquid to vapour or condensation may expose different surfaces. Use management-of-change review whenever the recipe, cleaning cycle or ordered construction changes. Reconfirm all wetted parts and documents rather than assuming that a model name alone preserves the previous assessment.