There is a basic distinction between static fittings and retractable fittings. The static fittings are available as flow-through fittings, generally for by-pass or inline applications directly within the process flow, and as immersion fittings for measurements in basins, tanks, or channels.
Retractable fittings – better described from a functional point of view as “sensor lock-gates” – can be used to remove and service a sensor under process conditions. This is done in either manual or pneumatic mode. This can be linked with an automatic cleaning and/or calibration function. Because of the variety of production conditions, the requirements for a fitting are as diverse as they are for a sensor. Pressure and temperature, the choice of materials and above all the type and symmetry of the installation and the desired functionality, are determined by the fitting.