Control of Classification Equipment

Automatic Ultrasound (Autofom)

Principle

Scanning of the carcass by ultrasound results in a series of cross-sectional profiles that are used to gain tissue depths and other distances for prediction of the lean meat content of the whole carcass and several parts of the carcass.

Error Sources

Known standard deviations

Item

Repeatability s(r)

Reproducibility s(R)

Reliability

  

  

  

  

 

Known possibilities for error

Error

Frequency

German observations

Error contribution expressed as standard deviation

German observations

Dry surface

Practically never, the carcasses, coming from the dehairing  drum, are always wet and smooth

  

Rigid pigs - does not fit into the instrument

  

Range of fat thickness > 40 mm

Unknown problem, our pigs have fat thicknesses < 30 mm

  

Dirty transducer

The cleaning of transducers is part of the daily maintenance. Within one workday the contamination causes no error.  

  

Broken transducer Can occur, caused by falling hook! The consequences are unknown, because in the single known case, the failure was promptly noticed, and the instrument repaired. (The transducer was exchanged.)
Tick switch failure  In case of fall out any of the switches, the instrument stops   
Gambrel switch failure and this stops the conveyor too.    

It should be noted / documented which instrument that are used, and for each instrument the program version  or EPROM number should be recorded to make it possible to track the used algorithm.

Daily control

Periodic control

Control of instrument

Control of instrument

  • Check paper in the log printer.
  • Morning control of the transducers
  • Control of ID input.
  • Control of tick switch.
  • Control of gambrel switch.
  • Analysis test.
  • At the end of each working day the transducer array must be cleaned.
 

The instruments are controlled by a public

officer in irregular intervals (2-3 times a year):

-         the transducer array is controlled by
means of a calibrating phantom

an analysis test is carried out by means
of a CD, different from that used in the
daily tests.

Once a year all instruments are re-calibrated    

by the gauging-office.         

 

Control of data

Control of data