Oven for the thermal conditioning of preforms, comprising a ventilation plenum

1. Oven ( 10 ) for the thermal conditioning of preforms made of thermoplastic, an oven ( 10 ) that is traversed upstream to downstream by an air stream (A) for cooling the preforms and that comprises successively, in the direction of flow of said air stream (A):

an air inlet zone ( 16 a ) that comprises at least one air inlet port ( 22 a ) through which said air stream (A) flows from the outside of the oven ( 10 ) to the inside of the oven ( 10 ),

a zone ( 16 b ) for heating the preforms, that comprises means ( 64 ) for heating the preforms and at least one ventilation module ( 36 ) that is able to guide the air stream (A) coming from the inlet zone ( 16 a ) to the preforms,

an air extraction zone ( 16 c ) comprising at least one air extraction duct ( 68 ), the air extraction zone ( 16 c ) being traversed by the air stream (A) that flows from the heating zone ( 16 b ) to the outside of the oven ( 10 ),

wherein the air inlet zone ( 16 a ) of the oven ( 10 ) comprises an air distribution chamber ( 18 ) which is common to at least two ventilation modules ( 36 ) and which is arranged between the air inlet port ( 22 a ) having associated filtration means ( 26 a , 28 a , 26 b , 28 b ) and between the at least two ventilation modules ( 36 ), closest to the at least two ventilation module ( 36 ) which are connected to the said common distribution chamber ( 18 ), said common chamber constituting an air reserve from which the associated at least two ventilation modules ( 36 ) are able to draw some air.

2. Oven ( 10 ) according to claim 1 , wherein each ventilation module ( 36 ) has a rotor ( 44 ) mounted so as to rotate, and so as to draw in air contained in the common distribution chamber ( 18 ) and to blow the air drawn in in this way to the preforms.

3. Oven ( 10 ) according to claim 1 , wherein the distribution chamber ( 18 ) is in the form of a parallelepiped casing comprising at least:

a first large open lateral face ( 20 a ) that includes a first air inlet port ( 22 a ),

a second large open lateral face ( 20 b ) that is opposite and parallel to the first large face ( 20 a ) and that includes a second air inlet port ( 22 b ).

4. Oven ( 10 ) according to claim 3 , wherein each of the filtration means ( 26 a , 28 a , 26 b , 28 b ) comprises successively at least:

one upstream pre-filter ( 26 a , 26 b ) that is able to filter particles with a first given diameter, and

one downstream filter ( 28 a , 28 b ) that is able to filter particles with a diameter less than said first given diameter.

5. Oven ( 10 ) according to claim 4 , wherein each upstream pre-filter ( 26 a , 26 b ) is a gravimetric filter.

6. Oven ( 10 ) according to claim 4 , wherein each inlet port ( 22 a , 22 b ) has a shape flared out towards the outside of the oven ( 10 ), each upstream pre-filter ( 26 a , 26 b ) being arranged in the largest section of the associated air inlet port ( 22 a , 22 b ), upstream of the associated downstream filter ( 28 a , 28 b ), so that the cross section of the passage of each upstream pre-filter ( 26 a , 26 b ) is greater than the cross section of the passage of the associated downstream filter ( 28 a , 28 b ).

7. Oven ( 10 ) according to claim 3 , wherein the distribution chamber ( 18 ) has a large face ( 30 ) that extends orthogonally to said large lateral faces ( 20 a , 20 b ), and on which an air manifold ( 32 ) is connected that selectively connects each ventilation module ( 36 ) to the distribution chamber ( 18 ).

8. Oven ( 10 ) according to claim 4 , wherein the inlet zone ( 16 a ) has means ( 84 a , 86 a ) for detecting fouling of said filtration means ( 26 a , 28 a ), said detection means being able to measure:

a first pressure difference between a point situated directly upstream of the pre-filter ( 26 a ) and a point situated directly downstream of the pre-filter ( 26 a ), of the first inlet port ( 22 a ), and

a second pressure difference between a point situated directly upstream of the filter ( 28 a ) and a point situated directly downstream of the filter ( 28 a ) of the first inlet port ( 22 a ),

and of comparing each pressure difference with a respective predetermined pressure value, by virtue of which it is possible to evaluate individually the respective degrees of fouling of the pre-filter ( 26 a ) and of the filter ( 28 a ).

9. Oven ( 10 ) according to claim 2 , wherein the distribution chamber ( 18 ) is in the form of a parallelepiped casing comprising at least:

a first large open lateral face ( 20 a ) that includes a first air inlet port ( 22 a ),

a second large open lateral face ( 20 b ) that is opposite and parallel to the first large face ( 20 a ) and that includes a second air inlet port ( 22 b ).

10. Oven ( 10 ) according to claim 1 , wherein each of the filtration means ( 26 a , 28 a , 26 b , 28 b ) comprises successively at least:

one upstream pre-filter ( 26 a , 26 b ) that is able to filter particles with a first given diameter, and

one downstream filter ( 28 a , 28 b ) that is able to filter particles with a diameter less than said first given diameter.

11. Oven ( 10 ) according to claim 2 , wherein each of the filtration means ( 26 a , 28 a , 26 b , 28 b ) comprises successively at least:

one upstream pre-filter ( 26 a , 26 b ) that is able to filter particles with a first given diameter, and

one downstream filter ( 28 a , 28 b ) that is able to filter particles with a diameter less than said first given diameter.

12. Oven ( 10 ) according to claim 5 , wherein each inlet port ( 22 a , 22 b ) has a shape flared out towards the outside of the oven ( 10 ), each upstream pre-filter ( 26 a , 26 b ) being arranged in the largest section of the associated air inlet port ( 22 a , 22 b ), upstream of the associated downstream filter ( 28 a , 28 b ), so that the cross section of the passage of each upstream pre-filter ( 26 a , 26 b ) is greater than the cross section of the passage of the associated downstream filter ( 28 a , 28 b ).

13. Oven ( 10 ) according to claim 1 , wherein the inlet zone ( 16 a ) has means ( 84 a , 86 a ) for detecting fouling of said filtration means ( 26 a , 28 a ), said detection means being able to measure:

a first pressure difference between a point situated directly upstream of the pre-filter ( 26 a ) and a point situated directly downstream of the pre-filter ( 26 a ), of the first inlet port ( 22 a ), and

a second pressure difference between a point situated directly upstream of the filter ( 28 a ) and a point situated directly downstream of the filter ( 28 a ) of the first inlet port ( 22 a ),

and of comparing each pressure difference with a respective predetermined pressure value, by virtue of which it is possible to evaluate individually the respective degrees of fouling of the pre-filter ( 26 a ) and of the filter ( 28 a ).

14. Oven ( 10 ) for the thermal conditioning of preforms made of thermoplastic, an oven ( 10 ) that is traversed upstream to downstream by an air stream (A) for cooling the preforms and that comprises successively, in the direction of flow of said air stream (A):

an air inlet zone ( 16 a ) that comprises at least one air inlet port ( 22 a ) through which said air stream (A) flows from the outside of the oven ( 10 ) to the inside of the oven ( 10 ),

a zone ( 16 b ) for heating the preforms, that comprises means ( 64 ) for heating the preforms and at least one ventilation module ( 36 ) that is able to guide the air stream (A) coming from the inlet zone ( 16 a ) to the preforms,

an air extraction zone ( 16 c ) comprising at least one air extraction duct ( 68 ), the air extraction zone ( 16 c ) being traversed by the air stream (A) that flows from the heating zone ( 16 b ) to the outside of the oven ( 10 ),

wherein the air inlet zone ( 16 a ) comprises:

at least two ventilation modules ( 36 ), and

at least one air distribution chamber ( 18 ), called a plenum, which is interposed between the air inlet port ( 22 a ) and each of the ventilation modules ( 36 ), each ventilation module ( 36 ) being connected to the distribution chamber ( 18 ), and

wherein the distribution chamber ( 18 ) is in the form of a parallelepiped casing comprising at least:

a first large open lateral face ( 20 a ) that includes a first air inlet port ( 22 a ),

a second large open lateral face ( 20 b ) that is opposite and parallel to the first large face ( 20 a ) and that includes a second air inlet port ( 22 b ).

15. Oven ( 10 ) for the thermal conditioning of preforms made of thermoplastic, an oven ( 10 ) that is traversed upstream to downstream by an air stream (A) for cooling the preforms and that comprises successively, in the direction of flow of said air stream (A):

an air inlet zone ( 16 a ) that comprises at least one air inlet port ( 22 a ) through which said air stream (A) flows from the outside of the oven ( 10 ) to the inside of the oven ( 10 ),

a zone ( 16 b ) for heating the preforms, that comprises means ( 64 ) for heating the preforms and at least one ventilation module ( 36 ) that is able to guide the air stream (A) coming from the inlet zone ( 16 a ) to the preforms,

an air extraction zone ( 16 c ) comprising at least one air extraction duct ( 68 ), the air extraction zone ( 16 c ) being traversed by the air stream (A) that flows from the heating zone ( 16 b ) to the outside of the oven ( 10 ),

wherein the air inlet zone ( 16 a ) comprises:

at least two ventilation modules ( 36 ), and

at least one air distribution chamber ( 18 ), called a plenum, which is interposed between the air inlet port ( 22 a ) and each of the ventilation modules ( 36 ), each ventilation module ( 36 ) being connected to the distribution chamber ( 18 ),

wherein each air inlet port ( 22 a , 22 b ) has associated air filtration means ( 26 a , 28 a , 26 b , 28 b ),

wherein each of the filtration means ( 26 a , 28 a , 26 b , 28 b ) comprises successively at least:

one upstream pre-filter ( 26 a , 26 b ) that is able to filter particles with a first given diameter, and

one downstream filter ( 28 a , 28 b ) that is able to filter particles with a diameter less than said first given diameter, and

wherein each inlet port ( 22 a , 22 b ) has a shape flared out towards the outside of the oven ( 10 ), each downstream pre-filter ( 26 a , 26 b ) being arranged in the largest section of the associated air inlet port ( 22 a , 22 b ), upstream of the associated downstream filter ( 28 a , 28 b ), so that the cross section of the passage of each upstream pre-filter ( 26 a , 26 b ) is greater than the cross section of the passage of the associated downstream filter ( 28 a , 28 b ).