The YOKOGAWA FU20-10-T1-NPT, also cataloged as the FU20 pH/ORP combination sensor, operates as a dedicated hardware component for multi-parameter electrochemical liquid analysis within industrial process pipelines.

Hardware Specifications

Channel-to-Channel Isolation and Loop Protocol

The FU20-10-T1-NPT utilizes a polymerized saturated KCl reference system, which maintains signal stability in applications prone to reference electrode poisoning. This architecture facilitates integration with 4-20 mA HART loop protocol transmitters by providing distinct analog voltage signals for pH and ORP values. The internal Pt1000 temperature element allows the host transmitter to perform real-time Nernstian slope correction, ensuring measurement accuracy across variable process temperatures. The double junction design provides an effective barrier against electrolyte contamination, extending sensor longevity in harsh process fluids.

Frequently Asked Questions

Q: Does the 3/4 inch NPT connection require specific sealant for process isolation?

A: Yes, use an industry-standard PTFE thread tape or compatible liquid sealant suitable for the process chemistry. Ensure that only the threaded portion is exposed to the process, avoiding excessive torque that could compromise the wide-body casing.

Q: How can the reference junction be validated for functionality?

A: Periodic calibration against certified buffer solutions (pH 4.01, 7.00, 10.01) is required. If the slope deviates beyond the transmitter’s allowable window or the response time exceeds 30 seconds for a full-scale change, the sensor or the reference junction may require cleaning or replacement.

Field Installation Guidelines

1. Ensure the sensor orientation is within 45 degrees of vertical to maintain internal electrolyte contact with the junction.
2. If installing in-line, verify that the flow velocity is sufficient to prevent solids accumulation on the membrane, but not high enough to induce mechanical vibration or erosion.
3. Utilize the integrated 3/4 inch NPT thread for direct mounting, ensuring 5 full turns of thread engagement to guarantee pressure-tight sealing.
4. Connect the cable via the variopin interface, ensuring the connector O-ring is seated correctly to prevent moisture ingress at the electrical junction.
5. Perform a sensor-to-transmitter offset calibration immediately after installation to account for unique field conditions and cable impedance.