Fitting and method of using the fitting

A fitting for receiving a sensor, the fitting comprising:

• an outer housing which extends along a first axis and includes a primary medium inlet and a primary medium outlet for measurement medium to flow through the outer housing,
• wherein the outer housing includes a cleaning inflow channel, a cleaning outflow channel, and a fluid channel;
• an inner housing which extends along the first axis and is moveable about the first axis between a measurement position and a service position,
• wherein the inner housing includes a sensor chamber with a secondary medium inlet and a secondary medium outlet,
• wherein the secondary medium inlet is fluidically connected to the primary medium inlet, and the secondary medium outlet is fluidly connected to the primary medium outlet when the inner housing is in the measurement position,
• wherein the cleaning inflow channel is fluidically connected to the secondary medium inlet, and the cleaning outflow channel is fluidically connected to the secondary medium outlet when the inner housing is in the service position,
• wherein a gap of a preset gap width is formed between the inner housing and the outer housing;
• and
• a sealing unit arranged in the gap and having a preset sealing thickness, wherein the sealing thickness is greater than the gap width such that the sealing unit is pressed against the outer housing and against the inner housing with a first pressing force,
• wherein the sealing unit is elastic and includes a cavity therein, which is fluidically connected to the fluid channel and is configured to be pressurized by a fluid with a second fluid pressure such that the sealing unit is pressed against the outer housing and against the inner housing with a second pressing force, wherein the second pressing force is less than the first pressing force.