InPro 3250i Digital pH Sensor & InPro 3250 Analog pH Sensor Family
InPro 3250

InPro 3250 & InPro 3250i pH Probes

High Performance, High Accuracy In-Line pH & ORP Sensors

The InPro 3250 family is group of pre-pressurized, low maintenance pH and ORP sensors suited for an extensive range of applications in pharmaceutical and chemical industries. The InPro 3250 comes standard with a highly alkali resistant pH glass membrane and automatic temperature compensation to ensure the best possible measurement to meet your process demands. The digital InPro 3250i offers Intelligent Sensor Management (ISM) advanced diagnostics to manage maintenance and uptime.

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Designed for Longevity Without Drift

The InPro 3250 uses pressurized reference system with patented Argenthal silver-ion trap to prevent diaphragm clogging and to ensure gradual electrolyte outflow to extend the sensor's lifetime.

Suited for the Most Diverse & Intense Operating Conditions

With its durable design, the InPro 3250 family offers a series of pH-sensitive glass membranes that are suited for a variety of requirements, including low temperatures and steam sterilization.

Certified to Meet Various Environmental Needs

A set of certificates for a wide range of applications is available with the InPro 3250, including hazardous zones, biocompatibility of the electrolyte, and relevant safety regulations.

Meet Hygienic Process Conditions

Sensors in the InPro 3250 family are rugged electrodes that lead the industry for fast, accurate measurements even after repeated autoclaving or sterilization cycles at 140 °C (284 °F).

InPro 3250i Series Offers ISM Predictive Diagnostics

The InPro 3250i is a digital ISM pH and ORP sensor. The ISM technology provides predictive diagnostics that lower maintenance costs and reduces the risk of sensor failure during the process.

Simplify Installation with Plug and Measure Technology

Digital InPro 3250i pH sensors offer Plug and Measure technology, which stores calibration data in the sensor. A sensor can be calibrated away from the process, then quickly swapped-in when needed.

InPro 3250 Solution Ground (SG) Measures ORP

The InPro 3250 platinum auxiliary electrode (solution ground) eliminates the risk of electrostatic interference and enables joint pH and ORP measurement in a single sensor.

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What is the InPro 3250 family of pH sensors?

The InPro 3250 family is a series of pre-pressurized, liquid filled, METTLER TOLEDO pH sensors.  They have an integrated temperature sensor and are suited for an extensive range of applications in biotechnology, pharmaceutical manufacturing and chemical processing. The InPro 3250 family of pH sensors offers a wide selection of different pH-sensitive glass membranes to ensure the best measurement performance and sensor lifetime in your process environment. The InPro 3250 rugged, low maintenance electrodes lead the industry for fast and accurate measurements, even after repeated autoclaving or sterilization cycles. This family also includes digital sensors, the names of which end with an "i". These sensors, including the InPro 3250i, InPro 3251i and InPro 3253i pH sensors, use Intelligent Sensor Management (ISM) technology to provide fast Plug and Measure installation and predictive sensor health diagnostics.

What are different glass types in the InPro 3250 family?

There are four different types of pH-sensitive membrane glass in the InPro 3250 family. They are indicated by the 4th number in the product name.

  • InPro 3250 uses Highly Alkali Resistant Glass For Tough Conditions (HA Glass)
  • InPro 3251 uses Glass Suitable For Low Temperature (LoT Glass)
  • InPro 3252 uses Hydrofluoric Acid Resistant Glass (HF Glass)
  • InPro 3253 uses Steam Sterilizable Glass (A41 Glass)

Each type is suited for different applications, and your METTLER TOLEDO sales representative can support you in deciding which pH sensor is right for your application.

What is the difference between the InPro 3250 and InPro 3250i?

The difference between the InPro 3250 and the InPro 3250i is that the InPro 3250 uses analog technology while the InPro 3250i uses digital ISM technology. Plug and Measure is available with ISM as well as advanced predictive diagnostics to help manage your maintenance. The InPro 3250i reduces the risk of sensor failure, while improving process reliability.

Which model(s) of the InPro 3250 measures ORP?

All models of the InPro 3250i digital pH sensor have the ability to measure ORP (oxidation-reduction potential, or redox) in addition to pH. Additionally, select "SG" (solution ground) models of the analog InPro 3250 can also measure ORP. The ORP is an important parameter to describe the electrochemical conditions in a process. It is often used in chemical and pharmaceutical processes, and is a common measurement in biotech applications as well. 

What ISM features are available with the InPro 3250i?

Intelligent Sensor Management technology offered with the InPro 3250i helps you manage the maintenance of your pH and ORP sensors. The InPro 3250i series offers the following ISM features:

  • Plug and Measure technology, which simplifies sensor installation after calibration.
  • ISM Predictive diagnostics which help you to reduces the risk of sensor failure, while also improving process reliability.

What transmitters are the InPro 3250 and InPro 3250i compatible with?

The InPro 3250 models of pH sensor integrate with any appropriate METTLER TOLEDO pH transmitter. These include the M80, M100, M300, M400 and M800 transmitters. The pH transmitter you choose depends on your environment and complete measurement requirements. The exact transmitter for your application should be selected in consultation with your local METTLER TOLEDO representative.