This could include areas of application with heavy contamination or precipitation, as well as those with special requirements (such as sterilizability and hygienic applications). The automated and regular cleaning of the sensor can significantly increase its service life in problematic medium conditions. Applications are to be found in water and wastewater engineering, the pharmaceutical industry, the chemical industry and food technology.
The new type 202823 pneumatic retractable assembly can accommodate all standard commercial pH sensors with a fitting length of 225mm and a diameter of 12mm. In order to cope with the diverse process requirements, the retractable assembly comes in stainless steel (1.4404/316L). Different seal materials are also available. The robust design allows pressures up to 16bar and temperatures up to 140°C. The fitting is adapted to containers or pipeline systems by an appropriate flow-through vessel. A version with (EHEDG/3A) certified process connections is available for use in pharmaceutical applications.
The fitting can either be operated by an external (PLC) controller, or by the EXmatic 460 type control unit that is available as an option. To start measurement, compressed air is supplied to the fitting.
The pneumatic drive unit inserts the immersion tube into the process medium to the maximum immersion depth. A safety device prevents the immersion tube being inserted when there is no sensor installed. As soon as the "Measure" end position is reached, the controller receives pneumatic positional feedback. In this position, the terminal head of the sensor is concealed in the drive unit, making it impossible to remove it. Now the process liquid measurements are taken. If it is necessary to clean the sensor, it can be withdrawn from the medium without interrupting the process. To do this, move the fitting to the "Service" position. Positional feedback also indicates to the controller when this position is reached. The rinsing chamber is protected by seals in the "Service" position, so that no process liquid can escape.
Further information can be found on the Internet at: www.jumo.net.