Immersion Tube; Replacing The Immersion Tube - Knick SensoGate WA 133 Series User Manual

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The wetted part of the immersion tube is made of PTFE. The upper part of the immersion tube (T)
is provided with a stainless steel endpiece with bayonet contour (U). This endpiece serves for con-
necting the immersion tube to the drive unit of the retractable fitting.
The endpiece is aligned with the windows (Q) in the immersion tube and is non-rotatably con-
nected to the tube body (see the centerline in the figure below). This fixed alignment is imperative
to ensure that the retractable fitting can be easily installed and the sensor can be properly rinsed.
U
If the endpiece is not properly aligned or can be twisted, the tube is defective.
In this case, you must replace the immersion tube.
High process pressures and high process temperatures can cause the immersion tube to shrink
(known creep tendency of PTFE).
Before installing the immersion tube, always check its total length as shown above.
If the total length X is more than 2 mm shorter than specified (see figure and table), you must
replace the immersion tube.

Replacing the Immersion Tube

The immersion tube must be removed or replaced:
• for general maintenance
• for cleaning the immersion tube, e.g., after the sensor is broken
• for replacing the sensor gasket (O-ring)
• in the event of a technical fault of the drive unit
T
x
- 2 mm

Immersion Tube

Q
Short
x = 149 mm
SensoGate WA 133
Long
x = 204 mm