HH2800L Water Online Process pH Electrode | Low Temperature Medium Solution Electrode | LT Low-Temperature pH Membrane

The HH2800L is a combination pH electrode developed for liquid samples whose freezing-point depression allows pH measurement at temperatures as low as −25 °C. It is intended for refrigerated brines, compatible water-based antifreeze mixtures, cold surface water, and low-temperature industrial processes.

Its customized low-temperature PCG polymer-gel electrolyte is formulated to maintain reference-system function where conventional electrolytes may become more viscous and produce slower or less stable signals. A double-junction reference system adds another separation barrier between the process and internal reference element, helping slow the migration of sample contaminants.

The HA pH-sensitive glass membrane supports measurement across pH 0–14 in compatible acidic and alkaline aqueous media. The standard porous-ceramic junction provides ionic contact with the sample and can be configured with additional ceramic points or replaced by a ring-shaped PTFE junction according to the medium and installation conditions.

The HH2800L uses a PG13.5 process connection and can be supplied in insertion lengths from 120 to 425 mm. Multiple connector and temperature-sensor options allow integration with compatible inline, immersion, retractable, and laboratory measurement assemblies.

Standard configurations operate at pressures up to 3 bar. A reinforced version may be configured for pressures up to 6 bar, subject to the temperature and ratings of the complete installation.

Key benefits

• Low-temperature reference electrolyte: Customized PCG polymer gel supports reference-system operation down to −25 °C.
• Wide operating-temperature range: Suitable for compatible liquid samples from −25 to 100 °C.
• Double-junction reference: Adds a second barrier between the process and internal reference element.
• HA process-glass membrane: Intended for compatible acidic and alkaline aqueous liquids.
• Configurable process junction: Single-, dual-, or triple-point ceramic and ring-shaped PTFE options are available.
• Flexible process integration: PG13.5 connection with insertion lengths from 120 to 425 mm.
• Multiple transmitter interfaces: Several connector and integrated temperature-sensor options are available.

Configuration options

• Insertion length: Selectable from 120 to 425 mm according to the process installation.
• Junction configuration: Single-, dual-, or triple-point porous ceramic, or ring-shaped PTFE junction.
• Reinforced pressure construction: Available for applications requiring pressures above the standard 3 bar rating.
• Connector configuration: Multiple detachable cable and connector formats are available.
• Extended cable: Cable lengths up to 60 metres, subject to transmitter and installation compatibility.
• Integrated temperature sensor: Selectable NTC, Pt100, and Pt1000 options.

Low-temperature measurement notes

The sample must remain liquid at the measurement temperature. Ordinary water freezes near 0 °C, so operation below this point requires a liquid with sufficient dissolved salt, glycol, or another compatible freezing-point depressant.

Low temperature can slow the response of the glass membrane and reference system. Allow adequate stabilization time and confirm the response under representative process conditions rather than assuming room-temperature performance.

The transmitter and selected temperature element must support the complete −25 to 100 °C range. Automatic temperature compensation adjusts the electrode’s temperature-dependent slope; it does not convert the process sample to the pH it would have at another temperature.

For glycol solutions, concentrated brines, mixed solvents, or low-water-content samples, confirm the meaning of the reported pH, the calibration method, expected liquid-junction effects, and compatibility of all wetted materials.

Avoid rapid movement between very cold process liquid and warm buffer or cleaning solution. Thermal shock can damage the glass body, membrane, and seals.

The maximum pressure rating must be checked against temperature. Confirm that the electrode, holder, seals, process fitting, connector, and cable assembly share the required rating.

Application

• Refrigerated Brine Systems
• Water-Based Antifreeze & Coolant Systems
• Cold Surface Water Monitoring
• Low-Temperature Chemical Processing
• Cold-Climate Environmental Monitoring
• Laboratory Process Development