Description
ABB TBX5 pH probes with retractable TB557 / TBX557 options
ABB's TB(X)5 sensor family combines the measuring electrode, solid-state reference and available temperature compensation in one body. The Next Step reference is designed to reduce reference poisoning, plugging and pumping. TBX versions add a solution-ground rod for sensor diagnostics with suitable instrumentation.
TB557 and TBX557 retractable probes
The TB557 and TBX557 are ball-valve insertion sensors for hot-tap applications. The assembly permits servicing or replacement without interrupting process flow when installed and operated according to ABB's requirements. An integral anti-blowout lip is part of the sensor design.
The probe inserts through a 1¼ or 1½ in full-port ball valve, sold separately. Compression fittings and optional flush-and-drain hardware are selected with the installation. Confirm the complete valve, fitting, sensor and process arrangement before ordering.
TB557 / TBX557 specifications
| Application | Insertion and hot-tap, retractable mounting |
|---|---|
| Pressure / temperature rating | 690 kPa (100 psi) at 80°C (176°F); 276 kPa (40 psi) at 140°C (284°F), per the model specification on datasheet page 13 |
| Electrode body | PVDF (Kynar) |
| Sheath choices | 316 stainless steel, Hastelloy or titanium |
| Reference junction | Wood or PTFE; notched, or flush with flat electrode |
| External O-rings | Viton in the standard specification; confirm selected hardware materials |
| Length | 406 mm (16 in) standard; options up to 1,524 mm (60 in) |
| Measuring element | Replaceable electrode; pH glass and ORP selections available |
| Diagnostics | TBX557 adds the Next Step Advantage solution ground |
Temperature capability depends on the selected electrode, cable and assembly. Family-wide maximum ratings do not apply to every TB557 configuration. Confirm the applicable pressure and temperature limits with Milktronics and ABB.
Choose the electrode and reference junction
The family includes general-purpose pH glass (0–12 pH), flat glass, high-temperature and coating-resistant glass options (0–14 pH), and fluoride/acid-resistant glass (0–12 pH). Electrode temperature ranges differ; use the ordering table for the selected model. Platinum and gold ORP versions are also available.
ABB recommends wood junctions for many general-purpose applications where coating resistance is needed. PTFE is recommended for continuous service above pH 11 or where strong caustics, bleaches or other wood-delignifying chemicals are present.
Other TBX5 mounting styles
| TB551 / TBX551 | PPS body; twist-lock, inline or immersion |
|---|---|
| TB556 / TBX556 | PVDF body; threaded inline or immersion |
| TB561 / TBX561 | PVDF body; sterilizable inline applications |
| TB564 / TBX564 | High-pressure retractable hot-tap assembly |
| TB567 / TBX567 | High-pressure inline assembly |
These models have different construction and ratings. Milktronics can help compare them with the TB557 arrangement for your application.
ABB documentation
Download ABB TBX5 pH/ORP sensor datasheet — DS/TBX5-EN Rev. L, January 2026 (PDF)
The complete 32-page web copy includes TB557/TBX557 dimensions and ordering information, with searchable text and compressed images.
Request a retractable pH probe quote
Send the liquid composition, pH, operating temperature and pressure, insertion length, valve details and transmitter model. Include cleaning conditions and any special wetted-material requirements.
Request a configuration & quote
Call 352-602-6404. For digital EZLink connectivity, see the ABB 500 PRO-D pH sensor.
