• Weatherproof junction box
  • pH Range: ACCUGLASS™ 0 to 14pH
  • Repeatability: ± 0.05 pH
  • Temperature Compensation: 0 to 100°C (212°F)
  • Max process pressure: 100 psig
  • Max process temp: 212°F (100°C)
  • Maximum Pressure at Retraction: 64psig


The Rosemount Analytical Model 385 Retractable pH/ORP Sensor is designed to meet a wide variety of industrial applications. It has been specially designed for applications where the process cannot be shut down and a separate sample stream is difficult or impossible to provide. The Model 385 body is constructed with a standard titanium tube and Tefzel, allowing the sensor to be used in especially harsh applications such as bleach lines in paper mills.

The Model 385 Retractable pH/ORP Sensor is designed for use with a standard 1-1/2 inch ball valve. This makes it ideal for replacing or updating any manufacturer's existing retractable pH/ORP sensor without process shut-down. Initial installations can even be accomplished without process shut-down by hot tapping a 1-1/2 inch ball valve at the desired point of measurement.

Sensor removal is accomplished by retracting the sensor until it reaches the built-in mechanical stop (no cables or chains are required for retraction). The ball valve may then be closed, and the insertion sensor removed from the process. The entire process is accomplished with almost no loss of process fluid and without depressurizing the line. Once the sensor is removed from the ball valve it can easily be buffer checked or its disposable sensor tube replaced.

The Model 385 pH sensor comes standard with a triple junction gel filled reference cell. The peripheral ceramic liquid junction around the base of the glass electrode assures maximum working life even in solutions containing ammonia, chlorine, and other poisoning ions.

The plug-in style, solid state preamplifier is housed in a weatherproof junction box as an integral part of the sensor. This preamplifier provides noise free, long distance transmission of the pH/ORP signal to a remote analyzer, such as the Rosemount Analytical Models 3081pH/ORP, 54pH/ORP, 1054B pH/ORP, and many others. (Refer to the respective Product Data Sheets for further information.)


This product can be used in the following applications: