Submersible IP68 & H2S-Resistant Rotary Encoders for Water & Marine Infrastructure
For positional monitoring applications in wet environments, such as water treatment plants, dam spillways, and coastal sugar and coal terminals, standard rotary encoders cannot withstand prolonged exposure to moisture. This can range from atmospheric moisture and water to salt spray, or even the corrosive, humid environments of wastewater applications, which can destroy conventional seals and electronics in conventional encoders.
In this article, we highlight not just the most suitable IP rating for the intended wet environment, but also the chemical-resistant metallurgy to ensure you have the right positional monitoring tool for the right job.
IP67 vs. IP68 Submersible Encoders: Specifying for Continuous Immersion
Although, generally speaking, IP6* rated instruments have a degree of submersibility, the difference depends on the duration of immersion. IP67-rated encoders are tested for temporary immersion, with exposure times up to 30 minutes at a depth of 1 metre. IP68-rated encoders, however, are tested for continuous submersion. These positional monitoring instruments feature fully potted electronics and rubber seals to prevent air cavities and water ingress.
Combating Chemical & Marine Corrosion
In wastewater applications, such as wet wells or clarifier bridges, hydrogen sulphide gas is a common atmospheric waste byproduct. As these environments can be quite moist and generate heat, moisture and condensation can also form and collect on surfaces. Moisture and hydrogen sulphide can react to form sulfuric acid, which can greatly affect any metallic surfaces in the application environment.
To avoid this, typically select an encoder housing, flange, and shaft in 316L stainless steel or marine bronze to avoid corrosive effects in waste applications while also protecting against galvanic corrosion in marine environments. Due diligence must be applied to selecting mounting brackets, and fasteners are composed of compatible alloys to also prevent corrosion.
Gas-tight cable jackets are also suited to ensuring the communication from the encoder to the system remains robust. Standard PVC cables will turn brittle in these harsh atmospheres, eventually blackening the internal copper on the encoder's PCB. Specify factory-moulded, pressure-tight entries on both connectors as well.
Multi-Turn Absolute Feedback & Hazardous Area Compliance
Given these applications are typically harsh and cannot lose positional tracking during a power outage, encoders in these applications require uninterrupted position tracking. Energy-harvesting magnetic multi-turn encoders can provide monitoring without internal lithium backup batteries.
Additionally, given that these harsh environments can be prone to flammable gases or byproducts, an encoder with suitable Zone 1 & 21 or Zone 2 & 22 IECEx ratings helps prevent catastrophic failures.
PCA Encoder Range Supporting Water, Wastewater & Marine Criteria
Product / Model | Manufacturer | IP Rating | Enclosure & Materials | Sensing Technology | Water / Marine Suitability |
POSITAL UCD Series (e.g. UCD-CA01B-1212-D10D-PAV) | Posital Fraba | IP68 / IP69K (continuous submersion tested) | Heavy-duty 316L stainless steel or treated aluminium | Magnetic absolute multi-turn with Wiegand energy-harvesting (battery-free); 4–20 mA, CANopen, SSI, or Modbus | Submerged water sluices, penstock gates, and Archimedes pumps where position must be retained through station blackouts. |
Avtron AV56S | Avtron | IP66 / IP67 / Marine Duty | Cast 316 stainless steel housing with 100% potted electronics | Bearingless modular magnetic; eliminates mechanical bearings and dynamic shaft seals | Marine winch drums, raw sewage transfer pumps, and aeration mixers where seal ingress or ragging causes mechanical failure. |
PCA IPSW Series | PCA Encoders | IP66 / IP67 (submersion tested to 1 m) | Solid 316 stainless steel or anodised aluminium | Heavy-duty optical; greased double-lip elastomer shaft seals (Viton/FKM options) | Ship weather-decks, marine davits, wastewater grit channels, and outdoor coastal monitoring stations. |
PCA IPSG Series | PCA Encoders | IP66 / IP67 | Heavy-duty machined 316 stainless steel | Solid shaft optical with high radial/axial load-bearing packages and slurry-resistant sealing | High-shock tail pulleys on open-pit dewatering pumps and abrasive wastewater macerators. |
TWK LBET / TBX Series | TWK-Elektronik | IP68 / IP69K (underwater/subsea rated) | Seawater-resistant bronze or 316L stainless steel | Inductive non-contact ring (LBET) or dual-chamber potted absolute encoder (TBX) | Subsea equipment, dam spillway gates, and tidal water barriers subject to salt spray and continuous flooding. |
Need a Hand? Give Us a Call!
Finding a suitable solution for wastewater or marine environments can be challenging, but the PCA team is here to help! Send any questions through our contact page here, or call us directly on 1300 236 467.
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