> HO1 Gauge frames for harsh environments, clean rooms, and large width applications

The most stable and robust frame on the market

The series HO1 Frames are extremely robust and the beams are closed above and under the material to be measured.

The highly rigid frame allows the measurement of materials up to 12 meters wide and also makes it the ideal frame for delicate measurements where a high degree of accuracy is necessary.

The absence of opening over and under the material makes it the best choice for severe environments (dust, fibers, moisture, solvents, etc.) and also for very clean applications where dust, which might be generated by the scanner guiding system, cannot be tolerated on the material.

There are twenty frame sizes in this range, with a 500 mm width difference between models. The following table depicts the measurable material width for each model and type of sensor:

Type of frame XTiLE (X-Rays) LTD/LTD (Laser) IR4 or IR6 (Infra Red) BTi, PM147, KR85, Sr90 (Radioactive source)
HO1 - 25002550250026502600
HO1 - 30003050300031503100
HO1 - xxxxxxxx + 150xxxxxxxx + 150xxxx + 100
HO1 - 1150011550115001165011600
HO1 - 1200012050120001215012100

The gap, which is the distance between the two sensor heads, can be adjusted from 10 to 80 mm. The adjustment depends on the type of sensor, application, thickness of the material to be measured, and safety considerations.

The standard product pass line (distance from the floor at which the product passes) is between 810 and 830mm, and can be reduced to 770 mm if required. For higher pass line levels the scanner is mounted on adapted legs.


The frame is formed by a structure consisting of horizontal beams that have a cross section of 400 x 350 mm which has an extremely high Young's modulus (stiffness). For example, the deflection at the center of a 10 meter wide machine is less than xxxx. The resistance to torsion is also impressive. On the scanner's drive side, electrical components are installed in a thick welded enclosure that forms a very rigid upright. On the operator side, the frame is manufactured from 40 mm thick steel plate. This frame assembly has an exceptional strength and stability.

During final assembly, the complete guiding system is attached to surfaces directly machined on the already fully welded and assembled frame. This manufacturing method ensures that head alignment is perfect in all axes and no adjusting or leveling system is necessary. An alignment deviation of less than 0,2mm is achieved in all motion axes throughout the frame. This solution avoids the on-site difficult and extremely time consuming alignment maintenance operations.

The frame beams have side openings to allow passage of the carriages. This configuration is very practical for clean room environments because there is no risk that dust from the upper beam will fall on the material.

Another design benefit of the side opening is that dust, fiber, water or other matter from the measured material cannot fall onto the lower beam. This machine is therefore ideal for harsh environments such as non-woven material applications, float-knells, and coating or paper mill lines.

The operator side of the scanner is no wider than the frame upright (150x40mm). This small side profile minimizes obstructions for the line operators and hence facilitates easy and safe threading of the product through the scanner.

Optionally, the frames of series HO1 gauges can be opened on the operator side. In this case the upper beam is attached to the line frame and the operator side upright is then removed.

The pass line level includes mounting plates which are fixed on the operator side and mobile on the electrical cabinet side. On the mobile side, the mounting plate consists of two steel plates, one attached to the line structure and the other attached to the frame; they are linked together by roll bearings. The frame is then free to thermally expand or contract, thereby preventing possible mechanical deformations.

Anti vibration plates are also installed between the frame fixing plates and the mounting plates.

Air Circulation

Temperatures variations between the upper beam and lower beam can happen as the material being produced acts as a thermal shield between the two beams. In this case the two beams may not thermally expand/contract by the same amount. This results in frame deformation that cannot be compensated by the mobile mounting plate.

Even though these deformations are compensated by the sensors which are measuring the distance between the two heads constantly, Scantech philosophy is to completely avoid or limit active compensations. Thus, the HO1 frames are designed to allow a high rate air flow to circulate between and through the lower and upper beams.
This design homogenizes the temperature of the frame and avoids any mechanical deformation. The series HO1 Frames are the only ones on the market equipped with this feature.

Air circulation is an extremely effective method to ensure dimensional stability of the frame. Scantech supplies this frame on all machines where the measurements are highly sensitive. It’s the case for example, when the measured material is very thin, such as plastic bi-axially oriented film applications.

For most of the applications frame air circulation is not necessary. Nevertheless, Scantech uses it in harsh environments by blowing air directly into the guiding volume. This generates a slight over pressure so that dust and fibers cannot enter inside the beams. For example, it's a very useful feature for non-woven material applications.

Measurement Sensor Head Guidance

The measurement head guiding system consists of two carriages equipped with linear ball bearings running on hardened chrome rails (HRC 62). The assembly, statically over determined, is extremely stable. The sensor heads are mounted on these carriages.

The carriages are pulled by timing polyurethane belts reinforced with steel cables. The belt tensioning system can be easily disassembled from the carriages.

The belts are supported throughout the frame. Therefore, the belt tension can be adjusted optimally, avoiding vibration and premature wear, thereby increases the equipment reliability.

The upper and lower belts are coupled directly via a single shaft which transmits the motion. This assembly is extremely simple and is very reliable.

The belt fastening system on the carriages can easily be disassembled. It allows decoupling the heads easily and quickly for maintenance operations (for example to clean the sensor heads or to replace the sensor windows). Re-coupling the head is very simple. No alignment operation is necessary since a mechanical device automatically determines the relative sensor positions.

Covering / Protection of the guiding and the drive systems

Except for the area of passage of the sensor supports, the scanner is completely closed by covers hence protecting the guiding system from dust and fibers. The covers are designed to be easily and very quickly removed. Optionally they can be made of aluminum in order to reduce their weight and facilitate handling.

For very harsh environments, the scanner can be operated with higher internal positive pressure to further reduce internal contamination risks as explained above.


Reliability and ease of maintenance were closely studied in order to minimize machine down time. All maintenance operations are designed to be very easy and fast.


  • Lubrication of linear bearings: It's done with a standard grease gun with through access doors that are located at both ends of the scanner.
  • Measurement head uncoupling: Doors at both ends of the scanner provide direct access to the coupling system.
  • Head re-coupling: A mechanical system quickly resets the optimal head alignments without any type of specialized time consuming procedure.
  • Lubrication of pulleys: It can be done easily by removing only one cover fastened without screws.
  • Access to the motor and drive shaft: Again there is only one cover to remove (fastened without screws).

Electrical cabinet

All electrical components of the scanner are assembled in a cabinet mounted to the drive side of the frame. Scantech scanners are complete stand-alone machines that can be installed and set up much faster than conventional gauge systems with remote electrical cabinets that require additional wiring, testing, and interconnections troubleshooting.