4.1.4.2. Scanners
No matter how a scanner is designed, its structural shape is such that the transducer does not touch the surface of the product. Sensors can be adjusted to optimise the focus.
Possible line configurations are covered with 2 basic methods for mounting UMAC scanners:

a) Submerged operation: The so-called A-scanners are completely immersed: they can be directly "sunk" into available cooling troughs. There is no need for any cable guide: they are completely contact-free.
Such scanners are available for small cables (= 1 mm Ø) and for heavy cables with OD up to 200 mm.
They can be also mounted directly into the vacuum calibration tank following the extruder. A-scanners are extremely reliable due to the simplicity of their corrosion-free design.

b) With autonomous water supply: R-scanners are used where submerged operation is impossible or difficult (e.g. if measurement has to take place between two cooling sections or if there is not enough available space for submerged operation). A closed, circular chamber containing the ultrasonic transducers is filled with water from an external supply. Cable guides at the entry and exit points seal the ring and centre the measured cable. A collecting basin for the water leaking through the guides has to be provided.

4.1.4.3. High Test Coverage
The ultrasonic transducers are sampled at a high frequency, i.e. the measurement process "rotates" in a tight spiral around the running cable.
Example:
A 4-point scanner provides 300 measurement revolutions per second at a sampling frequency of 1200/second. If the cable is running at 100 m/min., the length of twist of the measurement spiral is of the order of 5 mm. This means that the thickness of the sheathing is tested nearly without any gap.

UMAC® Scanner overview 4, 6, 8 Point Scanner with inlet for its own water supply

Miniscanner for mounting in the existing cooling trough

A-Scanner with its own Waterbath for attachment to the start of the cooling trough. (with adjustable input and output membrane seal)

A-Scanner for submerged operation

Submerged or with own water supply

A-Scanner for submerged operation

R-Scanner with its own water supply inlet mounted between 2 cooling troughs

4.1.4.4. Examples of Applications
The coating process used to lay the coaxial sheathing during production may undergo some deviation from a concentric distribution. Customers using automated cable strippers require cables with especially narrow tolerances.

a) Solution
Continuous monitoring of the PVC, PE and PU sheathing's centering of semi-finished coax cables based on sheathing wall thickness measurement with 4 ultrasonic sensors offset at 90°.

Scanner in operation

UMAC®-ECOWALL

4.1.4.5. Example with CAT 5 Datacable
The extrusion of the sheathing with expensive material must be controlled exactly. Reason is the high material cost as well as the demand for quality documentation. UTP cables (Unshielded twisted pairs) where there is no metallic subconstruction available represent a typical Ultrasonic application.

a) Solution
A 4 point A-Scanner is flanged directly on to the start of the telescopic cooling trough. It is in its own water bath with adjustable input seal.

c) Advantage
See point 4.1.4.4