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Homepage Alutal Wiki 01 - Introduction

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01 - Introduction

The concept of quality and customer satisfaction is part of day-to-day consumer and entrepreneurs. There is no more room for companies that do not practice the quality as its greatest value. And to ensure that quality is necessary and indispensable measure.

What is the quality of a product or service? Among the many informal settings, quality means being suitable to use, or have performance, durability, appearance, utility, and accordingly reliability expected by the customer.

Measuring a magnitude is to compare it with another unit called. The number that results from the comparison of a quantity with a unit is called the numerical value of the quantity.

Most measurements can not be performed only by a visual comparison between an unknown quantity and other known. It should have a measuring instrument.

Throughout our life we perform measurements, since measuring is a human need, and modernity is increasingly important to obtain reliable and accurate measurements.


From a technical point of view , when a measurement is performed it is expected that it is :

  • Exact , i.e. closest to the true value ;
  • Repetitive with little or no difference between measurements made under the same conditions ;
  • Reproductive with little or no difference between measurements made under different conditions.

Despite all the care , when we perform a measurement can a question arises : what is the correct value ? At this moment , it is necessary to use a measurement standard . A standard has the basic function of serving as a reference for comparison between the measurements performed .

This comparison process is called calibration that establishes the relationship between the values indicated by a measuring instrument and the corresponding standard values.

Calibration is performed by laboratories accredited by Inmetro or not . Inmetro - National Institute of Metrology, Standardization and Industrial Quality , is the body responsible for monitoring calibration and testing laboratories .


Before 1980 , only the Inmetro , IPEM and IPT is that were all calibration .

To " unburden " these laboratories in 1980 was created the Brazilian Calibration Network ( RBC) , which are " accredited " laboratories , that is in accordance with ISO / IEC 17025 .

The Alutal has its Laboratory accredited as Certificate No. 0522 CAL 



There are two calibration methods :

  • Comparison: the sensor to be measured is compared with another sensor with indicator called standard thermometer or sensor to a standard , calibrated by an Lab RBC ;




  • Set Points : To better express the laws of thermodynamics , was created a scale based on physical state change phenomena of pure substances that occur in unique conditions of temperature and pressure , are called fixed points of temperature. The change of state of pure substances (melting , boiling, etc.) is usually carried out without changing the temperature within a cell. All heat received or given by the substance is used by the state change mechanism. The values obtained at the sensor to be calibrated are compared to known fixed point .









State Balance
Temperatura (ºC)
triple point of hydrogen
- 259,34
boiling point of hydrogen
- 252,87
Boiling point of neon
- 246,048
Triple point of oxygen
- 218,789
Oxygen boiling point
- 182,962
triple point of mercury
- 38,834
triple point of water
0,01
Melting point of gallium
29,764
boiling point of water
100,00
Tin solidification point
231,968
Zinc solidification point
419,58
aluminum solidification point
660,323
Solidification point of silver
916,93
Gold solidification point
1064,43
copper solidification point
1084,62


Obs .: point is the triple point where solid , liquid and gas phases are in equilibrium .