Patent ID: 6903315

Claim:
A method for wrapping an article ( 3 ) in a sheet ( 4 ) of thermoplastic wrapping material; the method comprising: folding the sheet ( 4 ) around the article ( 3 ) in order to overlap at least two portions of the sheet ( 4 ); sealing said two overlapped portions by bringing the overlapped portions into contact with an at least partly metal belt ( 5 ) looped, which is heated by an electric current (I) induced by a first electric winding ( 13 ) coupled to said belt ( 5 ); detecting a temperature (T) of the belt ( 5 ); and controlling the electric current (I) induced in the belt ( 5 ) in order to keep the temperature (T) inside a given range; method being characterized by: determining a characteristic function, which relates the electric resistance (R) of the belt ( 5 ) to the temperature (T) of the belt ( 5 ); detecting a first signal (S 1 , S 3 ) related to the voltage (V) applied to the belt ( 5 ), and a second signal (S 2 ) related to the current (I) circulating in the belt ( 5 ); calculating the electric resistance (R) of the belt ( 5 ) as a function of the first signal (S 1 , S 3 ) and the second signal (S 2 ); and detecting the temperature (T) of the belt ( 5 ) using the characteristic function, which relates the electric resistance (R) of the belt ( 5 ) to the temperature (T) of the belt ( 5 ).