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

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 (16a) that comprises at least one air inlet port (22a) through which said air stream (A) flows from the outside of the oven (10) to the inside of the oven (10),
• a zone (16b) 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 (16a) to the preforms,
• an air extraction zone (16c) comprising at least one air extraction duct (68), the air extraction zone (16c) being traversed by the air stream (A) that flows from the heating zone (16b) to the outside of the oven (10),
• wherein the air inlet zone (16a) 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 (22a) 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 (20a) that includes a first air inlet port (22a),
• a second large open lateral face (20b) that is opposite and parallel to the first large face (20a) and that includes a second air inlet port (22b).

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 (16a) that comprises at least one air inlet port (22a) through which said air stream (A) flows from the outside of the oven (10) to the inside of the oven (10),
• a zone (16b) 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 (16a) to the preforms,
• an air extraction zone (16c) comprising at least one air extraction duct (68), the air extraction zone (16c) being traversed by the air stream (A) that flows from the heating zone (16b) to the outside of the oven (10),
• wherein the air inlet zone (16a) 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 (22a) and each of the ventilation modules (36), each ventilation module (36) being connected to the distribution chamber (18),
• wherein each air inlet port (22a, 22b) has associated air filtration means (26a, 28a, 26b, 28b),
• wherein each of the filtration means (26a, 28a, 26b, 28b) comprises successively at least:
• one upstream pre-filter (26a, 26b) that is able to filter particles with a first given diameter, and
• one downstream filter (28a, 28b) that is able to filter particles with a diameter less than said first given diameter, and
• wherein each inlet port (22a, 22b) has a shape flared out towards the outside of the oven (10), each downstream pre-filter (26a, 26b) being arranged in the largest section of the associated air inlet port (22a, 22b), upstream of the associated downstream filter (28a, 28b), so that the cross section of the passage of each upstream pre-filter (26a, 26b) is greater than the cross section of the passage of the associated downstream filter (28a, 28b).