Title:
PACKING MACHINE
Kind Code:
A1


Abstract:
A packaging machine is provided with a containing arrangement delimiting a processing volume having a longitudinal passing through dimension along which products to be packaged are moved; containing arrangement comprises an inlet arrangement for an air flow transversal to longitudinal passing through dimension and an outlet arrangement for air flow and a bottom portion adjacent to a body of the machine; the outlet arrangement extends substantially over the full extension of longitudinal passing through dimension.



Inventors:
Tacchini, Paolo (San Martino di Monte San Pietro, IT)
Application Number:
12/297199
Publication Date:
10/08/2009
Filing Date:
04/12/2007
Assignee:
A-PACK TECHNOLOGIES SA (Courroux, CH)
Primary Class:
International Classes:
B65B31/00
View Patent Images:



Primary Examiner:
HARMON, CHRISTOPHER R
Attorney, Agent or Firm:
NIXON & VANDERHYE, PC (ARLINGTON, VA, US)
Claims:
1. 1-28. (canceled)

29. Packaging machine provided with a containing arrangement delimiting a processing volume having a longitudinal passing through dimension along which products to be packaged are moved, said containing arrangement further comprising an inlet arrangement for an air flow transversal to said longitudinal passing through dimension and an outlet arrangement for said air flow and a bottom portion adjacent to a body of the machine, wherein said outlet arrangement extends substantially over the full extension of said longitudinal passing through dimension.

30. Machine according to claim 29, wherein said outlet arrangement comprises an intake duct having a substantially “C” like shaped cross section open towards said processing volume, said duct extending substantially adjacent to said bottom portion and inside said body.

31. Machine according to claim 29, wherein said body comprises a first wall and a second wall delimiting said processing volume.

32. Machine according to claim 31, wherein said first wall is suitable for supporting a plurality of operating stations arranged within said processing volume for performing packaging operations.

33. Machine according to claim 32, wherein said first wall comprises a first wall portion substantially orthogonal to a supporting plane of the machine.

34. Machine according to claim 33, wherein said first wall comprises a second wall portion inclined with respect to said first portion.

35. Machine according to claim 31, wherein said outlet arrangement comprises an intake duct having a substantially “C” like shaped cross section open towards said processing volume, said duct extending substantially adjacent to said bottom portion and inside said body and said second wall comprises a set of wall portions defining said intake duct.

36. Machine according to claim 30, wherein said outlet arrangement comprises a duct arrangement suitable for connecting said intake duct with said inlet arrangement of the air flow.

37. Machine according to claim 36, wherein said duct arrangement comprises at least one union duct suitable for connecting said intake duct with an outlet duct that is connected with the inlet arrangement.

38. Machine according to claim 29, comprising a further outlet arrangement opposed to said outlet arrangement and extending substantially over the full extension of said longitudinal passing through dimension.

39. Machine according to claim 38, wherein said further outlet arrangement comprises a further intake duct having a substantially “C” like shaped cross section open towards said processing volume.

40. Machine according to claim 39, wherein said further intake duct extends substantially adjacent to said bottom portion.

41. Machine according to claim 39, wherein said further intake duct extends externally to the containing arrangement.

42. Machine according to claim 39, wherein said further outlet arrangement comprises further duct arrangement suitable for connecting said further intake duct with said inlet arrangement.

43. Machine according to claim 42, wherein said further duct arrangement comprises at least one further union duct suitable for connecting said further intake duct with a further outlet duct that is connected with said inlet arrangement.

44. Machine according to claim 38, wherein said further outlet arrangement comprises at least one outlet opening adjacent to said bottom portion and communicating with an external environment.

45. Machine according to claim 44, wherein said outlet opening is made on a frontal wall of said containing arrangement and/or in the bottom portion.

46. Machine according to claim 43, comprising two further union ducts that connect opposing ends of said further intake duct with respective further outlet ducts.

47. Machine according to claim 43, wherein said duct arrangement comprises at least one union duct suitable for connecting said intake duct with an outlet duct that is connected with the inlet arrangement and said union ducts are substantially orthogonal to the respective intake ducts and substantially parallel to a supporting plane of the machine.

48. Machine according to claim 47, wherein said outlet ducts are substantially orthogonal to the respective union ducts and orthogonal to said supporting plane.

Description:

The present invention concerns an automatic machine for packaging products in environment with controlled atmosphere, for example sterile atmosphere.

In particular, the invention relates to a packaging machine provided with containing means that gives rise to a processing volume with aseptic/sterile atmosphere, said processing volume being suitable for packaging products, for example drugs, cosmetics, food.

In the pharmaceutical and biotechnological industry the demand is known of carrying out packaging processes performed with sterile materials and in sterile environments, for preventing the packaged products from being possibly subjected to contamination of particle and bacteriological type, due to the presence in the untreated air of solid particles in suspension, such as ashes, spores, microorganisms.

For this purpose, the packaging machines are inserted in the interior of sterile rooms, that separate an internal processing volume, precisely sterile, from an external surrounding environment not sterile or having different class of sterility or contamination.

Such machines are generally provided with containing means having the shape of a cabin, that, besides preventing the access to moving parts of the machine, delimits and separates an internal volume from the environment of the clean room. The cabin actually provides to limit the interventions of the operators and prevent them from directly interacting with sterilized parts and components of the machine. On the walls of the cabin are present special openings provided with gloves, so-called “glove ports”, by means of which the operators are capable of manipulating objects into the processing volume, without coming in directed contact with said objects.

In fact, although within the clean room the operators are provided with protective suits and gloves, they constitute a potential contaminating source. The close proximity and the contact of said operators with sterile objects may cause the contamination of said objects.

It is provided that the cabin may be in flow connection with the clean room or completely insulated and sealed. In this latter case, the packaging machine can be positioned also in an environment with not controlled atmosphere.

In some applications, the separation and the insulation of the processing volume are needed also for preventing products potentially toxic and harmful for the human health from being dispersed in the external environment.

The sterility of the processing volume is assured by cleanliness and sterility of any component and element contained within the clean room and by the presence of a proper unidirectional flow of sterile air, filtered by proper high efficiency filters (HEPA—High Efficiency Particulate Air).

The unidirectional air flow consists of air filaments that move in the same direction, virtually mutually parallel and at substantially equal speed, so as to create a homogeneous air stream with no turbolences. The air flow, flowing down from top towards the bottom, gives rise to a front of sterile air that entrains along the contaminating particles possibly present in the room and prevents them from rising again from the bottom of the room.

Within the containing cabin an unidirectional air flow is also provided having virtually vertical development, from top towards the bottom, in particular at the operating regions wherein the packaging operations take place, for example, dosing of the product in the containers, closing and providing said containers with a metal ring. In particular, in the case of packaging of the drugs under sterile air flow, the speed of said air flow is required to be of about 0.45 m/s at the operating regions.

The air flow licks the containers and also in this case gives rise to a front of sterile air that prevents potentially contaminating particles from penetrating into the containers. That is possible only when the air flow is virtually unidirectional and uniform, because possible turbolences could lead the contaminating particles exactly in the operating regions.

In order to obtain a uniform and unidirectional air flow inside the cabin, besides proper conditioning means being to disposal suitable for generating and conveying such air flow, intake ducts or ducts for retrieving the air must be provided, capable of collecting the air from the bottom of the cabin and conveying said air towards the exterior, directly in the clean room or conveying said air to said conditioning means.

The proper positioning and dimensioning of the intake ducts actually enable the turbolences in the air flow to be limited and possibly formed only at the bottom of the cabin, where the impact of the flow takes place.

The air flow must further impact and involve all the portions of the inner space of the cabin, to prevent formation of stagnating regions, wherein due to the absence of movement of the air the contaminating particles could deposit and concentrate.

The insufficient and not uniform distribution of the air flow inside the cabin, with consequent formation of stagnating regions, represents a problem also during the sterilization phase. In such stagnating regions the sterilizing agent can actually accumulate, typically gaseous hydrogen peroxide, used for sterilizing the interior of the cabin and groups or operating stations of the machine. The aerating or ventilating procedure, necessary for fully eliminating any remnants of such sterilizing agent within the cabin after the sterilization, results thus relatively long and laborious, because the air is not able to reach and properly ventilate such stagnating regions.

In the case of packaging machines having so called bed structure and provided with containing cabins, it is noted that the turbolences arising during the functioning can strongly disrupt the unidirectional air flow also at the operating regions.

That is imputable to the reduced distance that separates the bottom of the cabin from the operating regions with respect to the remarkable transversal dimensions of said cabin, i.e. the dimensions of the bed of the machine whereon said cabin rests.

In such a type of machines, in fact, the horizontal supporting plane whereon the operating groups are fixed constitutes the bottom of the cabin. The actuating members and the mechanisms of the operating groups, contained in the bed of the machine, are arranged below the supporting plane. Since the height from the ground of the operating groups is defined and imposed, in order to enable these latter to be lightly reached by the operators, the distance between supporting plane and operating groups, that is the operating packaging regions, must be necessarily limited. Such distance results generally insufficient for preventing the turbolences that generate on the supporting plane from rising again and involving the operating regions.

Besides that, in such machines in order to limit the height of the supporting plane from the ground, the width of the bed has to be increased, in order that said bed can contain all the necessary moving members.

The considerable width of a bed machine causes, also in the case where opposing intake ducts are provided along both the longitudinal sides of the cabin, not suitable intake flows of the air, with turbolences and/or stagnating regions being mainly generated in the more distant points from the ducts, that is at the central region of the machine, wherein generally the operating groups are arranged.

In order such problems to be avoided, packaging machines are used having so called “wall” or “shoulder” structure, wherein the operating groups are cantilever like mounted, fixed to a substantially vertical plane of the bed. Thus, a machine can be obtained with reduced transversal dimensions, since the bed can develop in height next to the processing volume defined by the containing cabin. At the same time, the bottom of said containing cabin results reasonably distant from the operating regions so as to reduce the turbulence phenomena of the air that can involve said regions. The intake ducts of the air are arranged on the bottom of the cabin.

Wall packaging machines are known, wherein the bottom of the cabin has the function of intake duct for conveying the air towards two collecting openings placed at opposing ends of the machine, respectively upward and downward of the operating groups, with respect to a longitudinal advancing direction of the product to be packaged. The bottom of the cabin is actually provided with a series of grids allowing the passage of the air and forming a sort of retrieving duct. However, wide stagnating regions develop inside such duct, mainly in the central region more distant from the retrieving openings, at which central region the air flow coming from top separates for reaching the openings.

Besides this, cleaning of the duct results quite laborious and lengthy because said cleaning requires the grids to be disassembled since inside said duct, besides contaminant particles, there are deposited remnants of packaged product and all that is capable of falling from the operating groups. In the case of a packaging process in sterile atmosphere, the deposition of such particles and remnants on the bottom of the cabin, i.e. inside the processing volume, may cause a possible contamination of such volume or in any case a downgrading of the sterility grade of said volume.

Wall packaging machines are known provided with containing cabin, wherein the intake of the air is made by means of an intake tube arranged longitudinally below the operating groups over the full length of the machine. The tube is provided with a plurality of openings through which the air can be conveniently sucked.

However such solution exhibits some drawbacks. First of all the tube is not generally continuous, but subdivided in a plurality of separated sections, because its transversal dimensions are such to interfere with the sizes of the operating stations of the packaging machine. Such sections in some cases may not be sufficient for assuring a homogeneous and uniform suction of the air flow along the full length of the machine, determining the potential formation of turbolences and stagnating regions more or less wide.

Furthermore, such tube constitutes an object that, interposed between the operating stations and the bottom of the cabin, makes complex and critical the cleaning and sanitizing procedure of said cabin, forcing in some cases to its dismounting with consequent growing of the times and the costs. In fact, contaminant particles, remnants of packaged product and containers may collect and accumulate between the intake tube and the bottom of the cabin, that, in the case of a packaging process in sterile atmosphere, may cause a partial contamination of the processing volume or in any case a downgrading of the sterility grade of said volume.

An object of the present invention is to improve the automatic machines provided with containing means for packaging products in environment with controlled atmosphere. Another object is to obtain a packaging machine enabling a virtually uniform unidirectional air flow to be realized in the processing volume inside the containing means, so as to eliminate or remarkably reduce the formation of turbolences, mainly at the packaging operating regions.

Further object is to realize a packaging machine enabling a unidirectional air flow to be obtained capable of reaching and lick with proper speed all the portions of space inside the containing means, so as to eliminate or remarkably reduce the formation of stagnating regions of the air flow.

Still another object is to obtain a machine that is suitable for being easily and lightly cleaned, sanitized and sterilized, in all the points inside the containing means and in particular at the bottom of the cabin.

According to the invention there is provided a packaging machine provided with containing means delimiting a processing volume having a longitudinal passing through dimension along which products to be packaged are moved, said containing means further comprising inlet means for an air flow transversal to said longitudinal passing through dimension and outlet means for said air flow and a bottom portion adjacent to a body of the machine, characterized in that said outlet means extends substantially over the full extension of said longitudinal passing through dimension.

Owing to the invention a packaging machine can be obtained enabling an air flow to be realized in the processing volume wherein turbolences are absent or remarkably reduced, mainly at the operating packaging regions, and stagnating regions are absent, mainly at the bottom portion.

The presence of outlet means comprising at least one intake duct having open cross section that extends over the full length of the machine actually contributes to stabilize the unidirectionality and the uniformity of the air flow. Furthermore, the intake duct assures a regular and uniform outflow of the air preventing the formation of turbolences and stagnating regions at the bottom portion of the containing means, at any point over the full longitudinal development of the machine.

The achievement of the intake duct inside the body of the machine further enables a machine to be obtained suitable for being easily and lightly cleaned, sanitized and sterilized, in particular at the bottom of the cabin.

The invention can be better understood and carried out with reference to the enclosed drawings, that illustrate an exemplifying and not restrictive embodiment form thereof, wherein:

FIG. 1 is a schematic front view of the packaging machine according to the invention;

FIG. 2 is a section according to a plane II-II of FIG. 1;

FIG. 3 is a section according to a plane III-III of FIG. 1, highlighting the development of air flows inside a processing volume and outlet means of the machine;

FIG. 4 is a partial section according to a plane IV-IV of FIG. 1;

FIG. 5 is a partial section like FIG. 4 of a variant of the machine;

FIG. 6 is a section according to a plane VI-VI of FIG. 5;

FIG. 7 is a section according to a plane VII-VII of FIG. 5, highlighting the development of air flows inside the processing volume and the outlet means;

FIG. 8 is a section like FIG. 7, highlighting a further variant of the machine;

FIG. 9 is a section like FIG. 3, highlighting a further variant of the machine.

With reference to FIGS. 1 to 4, a packaging machine 1 is shown provided with containing means 2, substantially comprising a room delimiting a processing volume 20 that exhibits a longitudinal passing through dimension along which products to be packaged are moved, for example containers advanced by transport means 60 through a sequence of operating stations 61, 62 suitable for performing respective packaging operations.

The containing means 2 comprises a bottom portion 8 adjacent to a body 3 of the machine, that contains the members and the moving mechanisms of the transport means 60 and the operating stations 61, 62.

The containing means 2 further comprises inlet means 30 for an air flow F, directed transversally with respect to said longitudinal passing through dimension and outlet means 6, 13, 14 arranged for enabling the outflow of said air flow F and extending substantially over the full development of said longitudinal passing through dimension.

In particular, the outlet means 6, 13, 14 comprises an intake duct 6 having a substantially “C” like shaped cross section, open towards the processing volume 20. The intake duct 6 extends substantially adjacent to the bottom portion 8 and inside the body 3.

The inlet means 30 is arranged on an upper portion of the containing means 2 and comprises fan means 31 capable of generating an air flow and directing said air flow, through filter means 32, into the processing volume 20. The filter means 32 comprises high efficiency filters enabling a flow F of sterile air to be obtained.

The shape and the dimensions of the filter means 32 and the operating speed of the fan means 31 enable a top-down directed, virtually uniform and unidirectional air flow F to be obtained inside the containing means 2, substantially orthogonal to the longitudinal dimension of the machine.

In a version not shown of the machine, it is also provided that the air flow F can be obtained by properly conveying an air flow generated by fan members of a distinct conditioning equipment or of a clean room inside which the machine 1 is positioned.

The containing means 2 constitutes a barrier system that is called RABS (Restricted Access Barrier System).

The body 3 comprises first wall means 4 and second wall means 5 that delimit the processing volume 20 over the full length of the machine. More in detail, the wall means 4, 5 constitute the lower portion of a rear wall of the containing means 2, while the upper portion 21 of said rear wall is connected with, and supported by, an upper wall 7 of the body 3. This latter upper wall 7 is external to the processing volume 20, for example parallel to the supporting plane 90 whereon the machine 1 rests.

The first wall means 4 is predisposed to cantilever like support the transport means 60 and/or the operating stations 61, 62 and comprises a first wall portion 41 virtually orthogonal to the supporting plane 90 and a second wall portion 42 inclined with respect to said first portion 41 and interposed between this latter and the upper wall 7. The second portion 42 may also be of convex shape, for example rounded, cylindrical.

In a version not shown of the machine, the second wall portion 42 may be aligned and coplanar with the first portion 41 and may be connected with the upper wall 7, for example forming a right angle.

The second wall means 5 defines the intake duct 6, having open section and communicating with the processing volume 20, for example, through a single longitudinal opening 11. Such opening 11 is positioned under the first wall portion 41 and is facing a bottom surface 8a of said bottom portion 8.

The longitudinal opening 11 may be interrupted by a plurality of set apart posts, suitable for removably supporting protecting grids, that prevent the entry of objects, for example containers, capsules, caps or fragments thereof, accidentally fallen into the duct 6.

As shown in FIG. 2, the intake duct 6 may have a “C” like, quadrangular open section, for example a square or rectangular open section, the second wall means 5 comprising respective wall portions, respectively third wall portion 43, fourth wall portion 44, fifth wall portion 45 and sixth wall portion 46, mutually, virtually orthogonally connected. In particular, the third wall portion 43 is virtually orthogonal to the first wall portion 41.

The open section of the intake duct 6 may also have semicircular or semi-elliptical cross section.

The outlet means further comprises duct means 13, 14 suitable for connecting the intake duct 6 with the inlet means 30 of the air flow F, in order to enable the sterile air to recirculate inside the containing means 2, in a configuration called “cRABS” (closed RABS) or insulator, wherein the containing means 2 is insulated and sealed with respect to a surrounding external environment 50.

For this purpose, the two opposing ends of the intake duct 6 are connected by means of respective union ducts 13 with outlet ducts 14 connected with the outlet means 30.

The union ducts 13 are virtually orthogonal to the duct 6 and parallel to the supporting plane 90 and are contained, just like the duct 6, inside the body 3.

The outlet ducts 14 extend vertically, virtually orthogonal to the supporting plane 90, through the body 3 at a rear wall 9 of said body 3.

However, it is provided that said outlet ducts 14 can be positioned at the exterior of the body 3, for example adjacent to the rear wall 9.

Similarly, the union ducts 13 can be arranged externally to the body 3, for example, along the flanks of this latter.

The arrangement of the union ducts 13 and the outlet ducts 14 is in function of the dimensions and the structure of the packaging machine 1, of the environment 50 wherein said machine is arranged, of the dimensions and the position of other packaging machines with which said machine 1 is connected.

The dimensions of the longitudinal opening 11 and the cross section of the duct 6 are evaluated so as to assure a speed of the air flow at the interior of said duct 6 ranging between 5 and 10 m/s. The exiting flow rate Q1 of the air through the duct 6 must be corresponding to the entering flow rate Q0 of the air introduced by the inlet means 30.

The entering flow rate Q0 is a function of the dimensions of a section S0 of the containing means 2 and the speed of the air flow F at said section S0.

The section S0 is substantially transversal and parallel to the supporting plane 90 and positioned at a distance of about 300 mm (1 ft) from a packaging region P where the packaging operations are carried out.

In the case of packaging of pharmaceutical products in sterile atmosphere, the speed required for the unidirectional air flow F in the section S0 is of about 0.45 m/s (±20%).

It is important to note that the machine according to the invention, owing to the presence of the intake duct 6 having open section, contributes to stabilize the unidirectionality and uniformity of the air flow F, particularly at the packaging region P, so as to assure the absence di turbolences or perturbations.

Besides this, it is noted a regular and uniform outflow of the air through the duct 6, that enables the development of turbolences and stagnation regions to be dramatically reduced at the bottom surface 8a, at any point along the full longitudinal passing through dimension of the machine.

The cantilever like arrangement of the operating stations 61, 62 and the transport means fixed to the first wall means 4, further enables the bottom surface 8a to be free from obstructions that could prevent and disrupt the air exiting flow. Besides this, the bottom surface 8a can be easily and lightly cleaned, sanitized and sterilized, in all the points thereof and over the full length of the machine, so as to enable particles and remnants possibly accumulated on said surface 8a to be eliminated.

In fact, it is noted that almost the totality of the particles and remnants transported by the air flow will deposit into the intake duct 6, i.e. outside the processing volume 20.

The intake duct 6 may be longitudinally inclined in direction of one of its own ends, for example for an angle ranging between 2° and 15°, for enabling the washing liquids to be drained, during the washing operations.

The development of the air flow F shown in FIG. 3, repeats substantially identical at any cross section of the machine 1.

The bottom portion 8 exhibits a longitudinal border 8b opposed to the border adjacent to the intake duct 6 and suitable for supporting the frontal wall 22 of the containing means 2.

The bottom surface 8a may be inclined for an angle ranging between 2 and 15° with respect to the supporting plane 90, in direction of the frontal wall 22 or a side wall of the containing means 2, for enabling the washing liquids, used during the sanitizing operations of the machine, to be collected in a proper portion of said bottom surface, where a draining outlet may be provided.

With reference to FIGS. 5, 6 and 7, a variant is shown of the packaging machine 1 comprising further outlet means 10, 15, 16 opposed to the outlet means 6, 13, 14 and extending substantially over the full development of said longitudinal passing through dimension.

The further outlet means comprises a further intake duct 10 having a substantially “C” like shaped cross section open towards said processing volume 20, for example through a single respective longitudinal opening 12.

Also in this case, the respective longitudinal opening 12 of the further intake duct 10 may be continuous or broken by spaced apart posts suitable for removably supporting protecting grids.

The further intake duct 10 extends substantially adjacent to said bottom portion 8, externally to the containing means 2 along the longitudinal border 8b of the bottom portion 8, parallel and opposed to the intake duct 6.

In particular, said further open duct 10 is interposed between the longitudinal border 8b of said bottom portion 8 and the frontal wall 22 of the containing means 2. The further longitudinal opening 12 is facing and opposed to the longitudinal opening 11 of the intake duct 6 and arranged virtually orthogonal to the bottom surface 8a.

The further intake duct 10 has, for example, trapezoidal open cross section, with an inclined side 10a positioned before the respective longitudinal opening 12 in order to convey the air within the duct.

The further outlet means further comprises further duct means 15, 16 suitable for connecting the further intake duct 10 with the inlet means 30 of the air flow F in order to enable the sterile air to be recirculated within the containing means 2.

More precisely, the two opposing ends of the further intake duct 10 are connected via further union ducts 15 and further outlet unions 16 connected with the inlet means 30.

The further union ducts 15 extend, for example, under the bottom portion 8 and the body 3, parallel to the supporting plane 90.

The further outlet ducts 16 extend vertically, virtually orthogonal to the further union ducts 15, for example, through the body 3 at the rear wall 7.

Also in this case the dimensions of the further intake duct 10 and in particular the dimensions of the respective longitudinal opening 12 and the open cross section are evaluated so as to assure inside said open cross section a speed of the air flow ranging between 5 and 10 m/s.

The further flow rate Q2 of the air exiting the further intake duct 10 and the flow rate Q1 of the air exiting the intake duct 6, once added, must be corresponding to the flow rate Q0 of the entering air.

In particular, the outlet means 6, 13, 14, 10, 15, 16 are dimensioned so that the exiting flow rates Q1 and Q2 are substantially equal, so as to assure the symmetrical distribution of the flow F, sucked and conveyed out of the processing volume 20.

Also in this case the configuration of the packaging machine 1 contributes to stabilize the air flow F so as to be unidirectional and uniform mainly in the packaging region P, here assuring the absence of turbolences or perturbations. The presence of two parallel and opposed intake ducts along the full longitudinal dimension of the machine enables a regular and uniform outflow of the air to be obtained and in particular enables a symmetrical distribution of the exiting air flow to be obtained, being virtually eliminated turbolences and stagnation regions at the bottom surface 8a of the containing means, as shown in FIG. 6.

FIG. 8 shows another version of the packaging machine, differing from the preceding version in that the further intake duct 10 is directly connected at the opposing ends thereof with the further outlet ducts 16. These latter extend vertically, virtually orthogonal to said further duct 10 and are adjacent to the frontal wall 22 of the containing means 2.

FIG. 9 shows a further version of the packaging machine 1 wherein the further outlet means comprises at least one or more outlet openings 18 provided on the frontal wall 22 of the containing means 2 and suitable for placing in flow communication the processing volume 20 with the external environment 50 and enabling then the air flow F to partially flow out.

The outlet opening 18 extends substantially over the full development of the longitudinal passing through dimension of the machine, at the longitudinal border 8b of the bottom portion 8 and results facing the longitudinal opening 11 of the intake duct 6.

The opening may be provided with protecting grids, arranged for preventing access to the processing volume from the external environment 50.

It is as well provided that the opening 18 can be made in the bottom portion 8, that is provided in this case with a respective side portion contained between the bottom surface 8a and the longitudinal border 8b, where said outlet opening is made.

In such a version of machine 1, the containing means 2 is not hermetically sealed, but partially open towards the external environment, according to a configuration known with the term of “mixed RABS”, wherein a portion of the air flow F is recovered from the intake duct 6 and admitted in the processing volume 20 from the inlet means 30 (air flow rate Q1′), the remaining portion of such flow F is dumped in the external environment, for example in a clean room inside which the machine 1 is positioned (air flow rate Q2′).

Exit of the air through the further outlet means 18 is assured by the overpressure existing inside the containing means 2 with respect to the external environment 50. Such overpressure prevents as well polluting particles from entering into the processing volume.

Also in this case the sum of the flow rates of air exiting through the intake duct 6 and the outlet opening 18 must be corresponding to the flow rate Q0 of air introduced through the inlet means 30.