Configured for high-temperature and chemically aggressive liquid analysis, the Yokogawa SC25V-ALP25-120 (SC25V Combined pH Electrode) provides direct physical signal acquisition for pH monitoring and temperature compensation within industrial process streams.

Hardware Specifications

Sensor Dynamics and Measurement Precision

The SC25V incorporates an integrated pH glass electrode, silver chloride reference, and Pt1000 temperature element within a robust PEEK body. To ensure accuracy in demanding environments, the electrode utilizes a PTFE reference junction and a titanium liquid earth to minimize electrostatic interference and chemical polarization. The sensing element is designed for high chemical resistance, effectively suppressing signal drift and cross-talk suppression in high-ion-concentration media. The inclusion of the Pt1000 element allows for real-time temperature compensation, critical for maintaining Nernstian slope integrity across fluctuating process temperatures.

Frequently Asked Questions

Q: Is the SC25V-ALP25-120 suitable for hazardous area installations?

A: Yes, the sensor is rated for Intrinsic Safety (IS) across ATEX, IECEx, and FM (US/CAN) standards, provided it is connected to a certified safety barrier appropriate for the specific zone classification.

Q: How does the titanium liquid earth benefit the measurement?

A: The liquid earth provides a stable reference potential for the sensor, neutralizing stray currents within the liquid stream that would otherwise introduce significant measurement noise or rapid reference junction degradation.

Field Installation Guidelines

• Ensure the electrode is installed at a 15-degree angle or greater from the horizontal to prevent air bubbles from accumulating on the glass membrane, which can induce erratic readings.
• Utilize the Variopin connector for a high-integrity, moisture-resistant signal path; ensure the mating cable connector is clean and dry during installation.
• Verify that the O-ring seals (Viton/EPDM) are lubricated and seated correctly to prevent bypass leakage and moisture ingress into the connector housing.
• Calibrate the sensor using standard buffer solutions after installation to establish the zero-point offset and slope baseline before subjecting the unit to process chemicals.