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Electronic Ear is useful for Control & Regulation of Ball Mills, using the grinding frequency signal for optimizing the Mill Output. It consists of an acoustic signal receiver (Microphone Unit / Sound Sensor) and specially constructed indicating & interpreting electronic circuit (Control Unit). Depending on the height of the material bed, the grinding media inside the Ball Mill causes a characteristic noise.

In case of high material bed (max. filling level), there is hollow grinding sound (low volume & low grinding frequency), whereas for low material bed (min. filling level), there is high pitched sound (high volume & high grinding frequency). This characteristic of grinding frequency is used to develop an output signal representing mill filling level, which can be used for regulation of the mill feed and / or for digital

indication of the mill filling level.

The Electronic Ear comprises of two parts viz. Microphone Unit (Sound Sensor) & Control Unit. The Microphone Unit comprises of a sturdy adjustable Bracket which permits radial and axial movement of the sound sensor, to suit the mounting requirement. Terminals are provided at the back, for termination of the signal cable. The Microphone Unit is to be connected to the Control Unit through a high quality single core shielded cable & it is to be mounted as near as possible to the jacket of the mill. Mounting stand is to be fabricated at site.

  Enables Optimization of mill Operation.
  Helps to take Precautionary Measures for avoiding jamming or empty running of mill.
  Enables Monitoring of Mill Performance.
  Helps in close circuit operation and automation of Ball Mills.
  Suitable for single or double chamber Mills.
  Bar Graph Display provided to indicate the Mill filling level.
  4-20mA Isolated Output in Normal or Reverse Mode.
  Di-Phonie Facility available for reducing ‘cross talk’ from adjacent mill.
  Signal injection facility for onsite calibration and checking.
  Control unit Enclosure made up from CRCA sheet steel, weather proof to IP-55 grade, powder coated suitable for field mounting.
  Industry proven product. Many successful installations on all kinds of Ball Mills, all over India and also at overseas locations.

Optional Features

  Selectable Power Supply (110V AC/230V AC).
  Potential free relay contacts for Hi & Lo Level.

Supply Voltage : 110V AC or 230V AC, 50Hz or 110V AC / 230V AC, 50Hz (Selectable) or 24V DC
Input : AC mV signal from Sound Sensor.
Frequency Range: 100 Hz to 2 kHz (Std). Unit Suitable for higher Frequency Range ( up to 9.99 kHz ) available optionally
Output : A) 4-20 mA; Normal Output or Reverse Output selection facility is provided through toggle Switch.
Normal Output: - 4-20 mA is directly proportional to Sound Level.
Reverse Output: - 4-20 mA is inversely proportional to Sound Level
B) Relay Contacts (Optional): 1 C/O each for Hi & Lo Level, continuously adjustable. Contacts rated for 5 Amps. Resistive at 240 VAC
Indication : Bar Graph Display provided to indicate the Mill Filling Level percentage
Di-Phonie Facility : To reduce the effect of 'Cross Talk' from Adjacent mill.
To use this facility, the adjacent mill also should have KANA make
"Electronic Ear"
Enclosure (Control Unit) : CRCA sheet steel, weather proof to IP-55 grade, powder coated, suitable for field mounting

Electronic Ear is mainly used for Ball Mill Level Indication and Optimization. It finds application in Process Industries which use Ball mills (for fine grinding / pulverizing) such as Cement, Steel, Power, Chemicals/ Fertilizer Industries etc.