Device for heating wrapped batches of products and installation for packaging by film wrapping batches of products

1. Device for heating wrapped batches of products, comprising:

an oven provided with at least one section;

at least one conveyor of said wrapped products passing through said at least one section;

means for heating said at least one section;

for each section, the heating means comprising at least one manifold ( 1 ) extending along at least a part of said corresponding section;

said at least one manifold ( 1 ) comprising at least one wall provided with orifices ( 2 ) of equivalent sizes, said orifices ( 2 ) being distributed in lines on the surface of said wall, the lines of orifices ( 2 ) extending horizontally forming rows, the lines of orifices extending vertically forming columns, the adjacent orifices ( 2 ) of the same line being spaced by at least one particular centre distance;

at least one means ( 3 ) for blocking the orifices ( 2 ) of at least two of the lines comprising at least one plate ( 4 ) mobile in at least one direction of movement relative to said wall of said manifold ( 1 ), said plate ( 4 ) comprising openings ( 6 ) spaced by an interval corresponding with each line of the orifices ( 2 ), each of the openings ( 6 ) having a length at least equivalent to the size of the orifice ( 2 );

wherein:

at least two of the successive openings ( 6 ) have different lengths, to go in said movement direction

a) from a position blocking at least a first line of orifices ( 2 ) and opening at least a second line of orifices ( 2 ),

b) to another position opening said first line of orifices ( 2 ) whilst maintaining open said second line of orifices ( 2 ).

2. The heating device according to claim 1 , wherein:

for each of the line of orifices ( 2 ), said corresponding openings ( 6 ) form an alignment in said direction of movement of said plate ( 4 ) or transversely to said direction of movement of said plate ( 4 ); and

said at least two successive openings ( 6 ) with different lengths belong to the same alignment.

3. The heating device according to claim 2 , wherein the interval between the openings ( 6 ) of the same alignment and the length of the openings ( 6 ) are adapted as a function of the centre distances between the orifices ( 2 ) and the sizes of the orifices ( 2 ).

4. The heating device according to claim 1 , wherein the interval between at least the openings ( 6 ) corresponding to the two successive lines of orifices ( 2 ) is a function of said at least one centre distance and at least one of the sizes of an orifice ( 2 ) of said two lines.

5. The heating device according to claim 4 , wherein said interval is equivalent to said at least one centre distance, reduced by one of the sizes of an orifice ( 2 ) of one of said two lines.

6. The heating device according to claim 1 , wherein for at least the first and second successive lines of orifices ( 2 ), the openings ( 6 ) corresponding to said second line have a length equivalent to the length of the openings ( 6 ) corresponding to said first line, increased at least by one of the sizes of an orifice ( 2 ) of one of said first or second lines.

7. The heating device according to claim 1 , wherein said plate ( 4 ) is mobile vertically in said direction of movement, each alignment of the openings ( 6 ) corresponding to each of the columns.

8. The heating device according to claim 1 , wherein said plate ( 4 ) is mobile horizontally in said direction of movement, each alignment of the openings ( 6 ) corresponding to each of the rows.

9. The heating device according to claim 1 , wherein said plate ( 4 ) is mobile horizontally in said direction of movement, each alignment of the openings ( 6 ) corresponding to each of the columns, and in that the lengths of the openings ( 6 ) extend horizontally.

10. The heating device according to claim 1 , wherein the orifices ( 2 ) of two of the adjacent rows (or columns) are offset horizontally (or vertically).

11. The heating device according to claim 1 , wherein the openings ( 6 ) corresponding to one of the lines of orifices ( 2 ) discharge through an edge of said plate ( 4 ).

12. The heating device according to claim 1 , wherein said plate ( 4 ) is mobile by a movement step at least equivalent to the size of the orifices ( 2 ).