Feltest AirSpeed Sensor (for SpeedController)

Article number: 000200

MEASURE PRESS FELT PERMEABILITY ON THE FLY

Permeability is key to understanding your felt’s condition. The Feltest AirSpeed Sensor helps you better plan your machine downtime, use the right amount of felt cleaning agents, and troubleshoot any performance problems.

€1,399.- excl. sales tax

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Better monitoring for better performance

It’s good practice to monitor the press felt condition on a daily basis. Permeability is key to understanding your felt’s condition, determining how water will flow through the felt mid-nip.

AirSpeed’s low-friction plastic measuring head contains a high precision vane that accurately measures the airspeed through the felt at both slotted and drilled uhle boxes.

If the airflow is low, poor sheet dryness or sheet crushing can be the consequences. High air flows indicate a very open felt, which can cause re-wetting or felt base marking.

Designed specifically for press felts

The AirSpeed’s low-friction plastic measuring head contains a high precision vane that accurately measures the airspeed through the felt at both slotted and drilled uhle boxes.

The telescopic carbon fiber rod makes it possible to safely measure at longer distances.

All parts of the AirSpeed Sensor are robust and built to last in the rough, hot and humid environment at the paper machine.

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It’s good practice to monitor the press felt condition on a daily basis. The Feltest AirSpeed Sensor helps you better plan your machine downtime, use the right amount of felt cleaning agents, and troubleshoot any performance problems.

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FAQ's

The AirSpeed Sensor measures how fast the air flows through the felt, into the uhle (felt suction) box. The moving air rotates a small vane (or propeller) inside the measuring head. The speeds is calculated by measuring how many times per second a propeller blade passes a small sensor.
This method is robust and works excellent under wet conditions.
Hot-wire anemometers work differently from the AirSpeed Sensor: a thin tungsten or platinum wire is heated up to a set hot temperature by using an electric current. Air passing by will cool down the wire, so extra current is required to get back to the set temperature. The additional current is a measure for the air flow.

The hot-wire is sensitive to corrosion, which is a weak point in the environment of a paper machine. That is why the AirSpeed Sensor is using a small vane (or propeller).
Yes, if the opening of the sensor head gets too dirty, the vane will rotate heavier, leading to incorrect (too low) values. To keep the test results accurate, make sure the measuring head stays clean.

On page 16 in our AirSpeed Sensor Manual, we explain how to clean the measuring head and the vane in only 3 steps.
Generally, the measured air speed should be between roughly 2 and 10 m/s. If the air speed is below 2 m/s, the Uhle box will barely remove water out of the press felt. Values over 10 m/s will only cost vacuum without increasing the amount of removed water.
Please note that the airspeed combined with the vacuum determines the overall press felt's condition. If you would like to know more about the applied vacuum in relation to the airspeed, look at page 10 of our SpeedController Manual.
No, you cannot. The white plastic measuring head needs to touch the felt/fabric. In the press section, on the uhle box, that is completely fine. In the forming section however, the sheet lays on top of the fabric. Touch the fabric would mean destroying the sheet.

The AirSpeed Sensor is ONLY to be used on press felts.

Here are some frequently asked questions about measuring felt permeability and the AirSpeed Sensor.

“The combination of a Caliper Profiler and an AirSpeed is extremely powerful when assessing press felt.”

—MARCEL LENSVELT

  
        Specifications
        AirSpeed Sensor
      
        Required Control Unit
        Feltest SpeedController
      
        Range
        0.5 - 20 m/s | 1.6 - 65 fps
      
        To be used on
        Press felts only
      
        Read-out units
        m/s, fps
      
        Length range of telescopic carbon rod
        610 - 1010 mm | 2 - 2.2 ft
      
        Length of cable
        Approx. 2 m | 6.5 ft
      
        Protection level
        IP68 (when connected to the SpeedController)
      
        Total weight
        0.4 kg | 0.9 lbs.