InPro 4260(i) & InPro 4281i Chemical Production pH Sensors

InPro4260 / InPro4260SG / InPro4260i

The ideal pH probe for chemical applications!

The InPro  4260 probes feature the new XEROLYT® EXTRA reference polymer for precise pH measurement and longer lifetime, even under the most difficult industrial environments.
The InPro 4260 probes come with an open junction, which solves the problem of diaphragm fouling often found in applications where sticky media, solutions with high particle content, or sulfide-bearing solutions are present. With other junctions, the electrical contact between the reference and the media is rapidly lost, and a sensor cleaning or even a non-scheduled sensor replacement is necessary.
Also available with "Intelligent Sensor Management" (ISM) for "Plug and Measure" and Advanced Diagnostics.

Specifications - InPro4260 / InPro4260SG / InPro4260i
pH-range 0 - 14 pH InPro 4260(i); 2 - 12 pH InPro 4261(i), InPro 4262(i), InPro4281i
Temperature 0 to 130°C (32 to 266°F)
Pressure 15 barg @ 25°C, 7 barg @ 130°C(217 psig @ 77°F, 101 psig @ 266°F)
Cable Connection ISM: K8S; Analog: VP
Process connection Pg 13.5 thread
Reference system Argenthal
Type of junction Open junction with direct contact to media
Reference electrolyte Xerolyt® Extra (patented)
Lengths 120mm, 225mm, 425mm
Shaft diameter 12mm
Shaft materials inPro 426x(i): Glass; InPro 428xi: Titanium
Temperature sensor ISM: DigitalAnalog: Pt100 or Pt1000
Sterilizable No
Autoclavable No
pH membrane Various by applications
Solution Ground InPro 426x(i): PlatinumInPro 428xi: Titanium
ATEX Certification SEV 14 ATEX 0168 XEx ia IIC T6/T5/T4/T3 Ga/Gb
FM approval IS/ I, II, III /1 /ABCDEFG /T6
IECEx Certificate of Conformity IECEx SEV 14.0025XEx ia IIC T6/T5/T4/T3 Ga/Gb
Features and Benefits
New XEROLYT® EXTRA polymer
  • It is the latest development of the pioneering XEROLYT® polymer reference electrolyte, successfully used over many years. Its patented composition minimizes measurement errors in almost all process media, leading to tighter process control.
ISM ("Intelligent Sensor Management®")
  • METTLER TOLEDO’s new and innovative, digital “Intelligent Sensor Management®” concept provides “Plug and Measure” functionality. ISM simplifies and improves the operation of process analytical systems from initial installation to maintenance to sensor exchange. ISM technology provides you with advanced diagnostic functions, lower maintenance costs and reduces the risk of sensor failure, while also improving process reliability. More information about ISM
Solution ground (SG) as an option
  • The SG feature as an entire electrode body coating or as a measuring point on a pH-electrode, will improve grounding and effectively eliminate the risk of electrostatic interference. SG also improves our advanced diagnostic functions, and makes parallel pH/redox measurement possible.
New rugged construction with titanium shaft
  • The new 4281i electrode provides exceptional chemical and mechanical resistance thanks to the titanium shaft and stainless steel thread.




Application Note: Improve Your Processes with ISM
In many ways, analytic measurements are at the heart of your process efficiency. Therefore, the lower your downtimes and maintenance requirement, and...
Application Note: pH Control in Sour Water Stripping
In petroleum refining, so called sour water (process water that contains dissolved hydrogen sulfide – H₂S) is produced in various processes. Due to en...
Minimal Corrosion: Thanks to pH Control
The installation of an intelligent in-line pH measurement with automated electrode cleaning allows for accurate control of sour water pH in Crude Unit...
Xerolyt® EXTRA Electrodes Optimize
A large chemical plant in Germany has been using Xerolyt pH electrodes in various process steps. Important is the very low maintenance requirement: no...
Application Note: Optimized Control of Sour Water in Petrochemical Applications
Application Note - Control of sour water without damaging the pH electrode
Application Note: Improve Your Pulp & Paper Process Further with ISM Technology
Many years of experience in the field of industrial measurement systems form the basis of METTLER TOLEDO’s competence. Now with its ground-breaking IS...
Easy ISM Sensor Management in Breweries
Application Note - iSense ISM Asset Suite the professional software tool to implement innovative and efficient maintenance concepts with pre-calibrate...


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InPro4260 / InPro4260SG / InPro4260i
USP Class VI
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