1. Introduction 

To give the best performance, KROHNE level meters must be installed in a correct way. Important instructions should be taken into consideration, like the mounting position, shape and height of the tank, obstacles within the tank, etc. Depending on the measuring principle of each device, the guidelines will differ. In this article we will explain the installation instructions for Non Contact Ultrasonic Level meters (OPTISOUND 3010 & OPTISOUND 3020 & OPTISOUND 3030).


2. Recommended installation guidelines

  • Select an installation position you can easily reach for mounting and connecting as well as later retrofitting of a display and adjustment module.
  • Make sure that a minimum distance from the reference plane (the so called dead band in which measurement is not possible) is maintained.

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  • If the medium reaches the transducer, buildup can form on it and cause faulty measurements later on.

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  • Low pressure or vacuum damps the ultrasonic pulses,this influences the measuring result,particularly if the level is very low. With pressures under 0.2 bar (20 kPa) you should use a different measuring principle like.radar or guided radar (TDR)
  • When mounting the OPTISOUND C, keep a distance of at least 200 mm(7.874 in)to the vessel wall.
  • If the sensor is installed in the center of dished or round vessel tops, multiple echoes can arise, these can, however, be suppressed by an appropriate adjustment. 
  • If you cannot maintain this distance, you should carry out a false signal storage during setup, this applies particularly if buildup on the vessel wall is expected. In such a case, it is recommended to repeat the false signal storage at a later date with existing buildup.

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  • In vessels with conical bottom it can be advantageous to mount the sensor in the center of the vessel, as measurement is then possible down to the lowest point of the vessel bottom.

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  • Preferably the transducer should be mounted flush to the vessel top.
  • If the reflective properties of the medium are good, you can mount OPTISOUND on a socket piece. You will find recommended values for socket heights in the following illustration. The socket end should be smooth and burr-free, if possible also rounded. Carry out a false echo storage.

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  • In liquids, direct the sensor as perpendicular as possible to the product surface to achieve optimum measurement results.
  • To optimally align the sensor to solid products, a swivelling holder (mounting strap) can be implemented.

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  • To reduce the min. distance to the medium, you can also mount OPTISOUND C with a beam deflector, by doing this, it is possible to fill the vessel nearly to maximum .Such an arrangement is suitable primarily for open vessels such as e.g.over flow basins.

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  • The ultrasonic sensor should be installed at a location where no installations cross the ultrasonic beam. Vessel installations such as for example, ladders, limit switches, heating spirals, struts etc. can cause false echoes that interfere with the useful echo, make sure when planning your measuring site that the ultrasonic signals have a clear view to the measured product.
  • If there are agitators in the vessel, a false signal memory should be carried out with the agitators in motion, this ensures that the interfering reflections from the agitators are saved with the blades in different positions.

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  • Do not mount the instruments in or above the filling stream, make sure that you detect the product surface, not the in flowing product.
  • Through the action of filling, stirring and other processes in the vessel, dense foams which considerably damp the emitted signals may form on the product surface.
  • If foams are causing measurement errors, the sensor should be used in a standpipe or, alternatively, the more suitable guided radar sensors (TDR) should be used.
  • If there are strong air currents in the vessel, e.g. due to strong winds in outdoor installations or air turbulence, e.g. by cyclone extraction you should mount OPTISOUND C in a stand pipe or use a different measuring principle,e.g.radar or guided radar (TDR).
  • By using a stand pipe (surge or by pass tube), the influence of vessel installations, foam generation and turbulence is excluded. Standpipes must extend all the way down to the requested min. level, as measurement is only possible within the tube.

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