WO2010134102A1

WO2010134102A1 - Apparatus and method for transferring powdered products

Info

Publication number: WO2010134102A1
Application number: PCT/IT2009/000222
Authority: WO
Inventors: Luca Catelli
Original assignee: Abc Pharmatech S.R.L.
Priority date: 2009-05-19
Filing date: 2009-05-19
Publication date: 2010-11-25

Abstract

Apparatus and method for transferring powdered products (2a) wherein a storage member (2) for storing a powdered product (2a) has a discharge tubular liner (4) extending from a respective outlet aperture (3) for discharging the product (2a); a conduit (5) for the passage of the powdered product (2a) has an inlet mouth (9) associable with a lower end (4b) of said liner (4) able to transfer the powdered product (2a) from the storage member (2) to the conduit (5); the conduit (5) exhibits coupling means (10) for associating the lower end (4b) of liner (4) with said conduit (5); separation means (27) are disposed between said storage member (2) and said conduit (5) for separating the lower end (4b) of liner (4) upon completion of a.discharge operation for discharging the powdered product (2a); the coupling means (10) comprise a first retention device (11) for retaining the lower end (4b) of liner (4) associated with the inlet mouth (9) of conduit (5), and a •second retention device (18) movable along said conduit (5) close to/away from the first retention device (11) for replacing the liner (4) with an exchange liner (4') disposed around said liner (4).

Description

"APPARATUS AND METHOD FOR TRANSFERRING POWDERED PRODUCTS" Technical field of the invention

The object of the present invention is an apparatus and a method for transferring powdered products. In particular, the present invention is used for transferring one or more types of powdered products, such as pharmaceutical products, held in respective storage hoppers . State of the Art As it is known, the powdered products are transferred by gravity from the storage hopper to an inlet channel of a relevant operating machine suited for treating such a product . Generally, the storage hopper is provided, in correspondence of a discharge outlet, with an outflow body, commonly known as "liner". The liner exhibits a substantially tubular structure and is made from a deformable material allowing it to be better conformed to the inlet mouth of the channel. In greater details, the liner has an upper portion coupled with the discharge outlet of the hopper, and a lower portion which is fitted onto the inlet mouth of the channel. In this way, the liner makes up a conduit for transferring the powdered products from the hopper to the channel.

To ensure optimal fluid seal and prevent possible ^■contaminations inside the liner and with the outer environment, suitable mechanical members are used for engagement around the inlet mouth of the channel. • In particular, the engagement members consist of a series of annular grooves formed on the outer surface of the channel .

In this way, the end of the liner fitted onto the channel is retained by the annular grooves and locked with adhesion thereto by mechanical members, such as 0-rings or straps, thereby determining a stable seal between the channel and the liner.

Preferably, a plurality of annular grooves is formed in order to retain two liners at the same time (one to be removed and one to be replaced), during the step of liner's exchange.

In fact, upon completion of transfer of the powdered product, the hopper is replaced by another which holds a second powdered product. Such operation is carried out by cutting the liner in correspondence of a central region to maintain a respective lower end anchored to the channel, and an upper end associated with the hopper. Besides, the separated ends of the liner are welded together along respective open edges to prevent the product in suspension inside the liner from being contamined by the outer environment.

Afterwards, the hopper is transferred to recovery facilities where the upper end of the liner is removed therefrom and the inside of same hopper is washed.

A second hopper, containing a fresh powdered product to be transferred, is brought in correspondence of the channel which is still provided with the said lower end of the liner previously separated. In this situation, the channel 'exhibits at least one further annular groove which is free, that is, is not engaged by the said lower end of the previous liner.

At this point, a further liner coupled with the second 'hopper is fitted over the channel and the lower end of the .previous liner.

The lower end of the second liner is therefore anchored to the free annular groove in such a way as to hold, within the same second liner, the lower end of the liner .previously utilized. In this way, by means of suitable pockets formed in the second liner, it is possible to withdraw the lower end of ■ the liner previously utilized so as to release the channel.

It is pointed out that, in this way, possible powders in suspension within the channel and the lower end of the utilized liner are not dispersed in the environment, but they do remain inside the second liner.

Such methodology, although able to avoid possible contaminations towards the external environment during the operations for the liners replacement exhibit, however, some major drawbacks.

The first drawback is due to the lack of versatility of the

^■channel's structure, inasmuch as it allows changing only a limited number of liners.

Actually, the number of liners that can be replaced on the channels results restricted by the number of free annular grooves formed on the same channel.

A second drawback stems from the fact that part of the ^• channel is put in contact with the product, thus making it necessary, at the end of the campaign, that is, upon completion of replacement of the liners, either to clean or to replace the latter with others in stock.

It should be noted that when the last annular groove (the groove furthest away from the inlet mouth of the channel) results engaged by the liner, it no longer possible to replace the lower surface of such liner inside a further exchange liner.

Description of the Invention

^'In this context, the technical task on which the present invention is based is to propose an apparatus and a method for transferring powdered products able to overcome the above drawbacks.

In particular, the object of the present invention is to •provide an apparatus and a method for transferring powdered products able to replace an illimited number of liners on a respective discharge channel. A further object of the present invention is to propose an apparatus and a method for transferring powdered products ensuring such a liner' s seal as to prevent the powdered product from being contamined by outer agents, and to prevent the external environment, including the liner- receiving hopper, from being contamined by said powdered product, both during and at the end of the operating procedure . The specified technical task and objects are substantially achieved by an apparatus and a method for transferring powdered products having the techinical characteristics set forth in one or more of the attached claims. Further characteristics and advantages of the invention will appear more clearly from a reading of the indicative and thus not limiting description of a preferred but non- •exclusive embodiment of an apparatus and a method for transferring powdered products as illustrated in the accompanying drawings, wherein:

- Fig. 1 is a schematic view, with some parts cut away to allow a better illustration of others, of an apparatus for trasferring powdered products according to the present invention;

- Fig. Ia is a sectional view of a constructional detail of the apparatus of Fig. 1; and - Figs. 2 to 13 are respective schematic views of

^' sequential operating steps for transferring powdered products by using the apparatus illustrated in Fig. 1.

With reference in particular to Fig. 1, numeral 1 indicates on the whole an apparatus for trasferring powdered products according to the present invention.

. In particular, the apparatus 1 is used for transferring one or more types of powdered products 2a, such as pharmaceutical products, held inside respective storage members 2. As illustrated by way of example in the attached figures, the storage member 2 of a respective powdered product 2a, is advantageously made up of a hopper provided with an outlet aperture 3 located in a respective lower portion. The outlet aperture 3 makes it possible to feed by gravity the product 2a to an operating machine (not shown in the figures as it does not make part of the present invention) . The apparatus 1 further comprises a tubular liner 4 for the discharge of the product 2a, said liner extending from the above indicated outlet aperture 3 of the storage member 2. The tubular liner 4 is advantageously made of a deformable material and is preset for connecting the member 2 with a conduit 5 for the passage of the powdered product 2a. The conduit 5 is only partially illustrated inasmuch as it makes up an inlet channel of the operating machine for the -treatment of the powdered product 2, or a transit pipe between rooms located at different floors.

In greater detail, the liner 4 exhibits an upper end 4a having an edge engageable with the outlet aperture 3, and a lower end 4b, associable with said conduit 5, as best described herebelow.

Also developing between the lower 4b and upper 4a ends is a hold portion 6 that can be set between a first operating condition in which it protrudes inside the liner 4 (Fig. 11) and a second operating condition in which it protrudes outside the liner 4 to define an inner storage chamber 7 (Figs. 12 and 13) .

Preferably, the liner 4 exhibits two hold portions 6 diametrally opposite to each other and each comprising a retractable glove 8. In particular, the glove 8 allows an operator to put one hand in it from the outside to gain access within the liner 4 (Fig. 11) . By pulling the retractable glove 8 outwardly of the liner 4, it is possible to define the said storage chamber 7 which develops within the liner 4 in order to retain a lower end 4b of a previously utilized liner 4 ( Figs . 12 and 13 ) .

Moreover, the liner 4 is preferably provided with a first and second clutch elements 30a, 30b able to be associated with a respective clutch elements 30a, 30b of a previously used liner 4.

In particular, the first clutch element 30a develops inside the liner in correspondence of a respective storage chamber 7. Such first clutch element exhibits an extended body provided with an interlocking pin. Likewise, the second clutch element 30b develops outside the liner in correspondence of the lower end 4b. Also the second clutch element 30b exhibits an extended body provided with an interlocking pin. 'In this way, as best disclosed herebelow, the interlocking pin of the second clutch element 30b of an already utilized liner 4, is firmly coupled to the interlocking pin of the first clutch element 30a of a liner to be repositioned.

Advantageously, the clutch elements 30a, 30b coupled to

■each other allow retaining, inside a respective exchange liner, the lower end 4b of the already utilized liner 4.

The conduit of passage 5 has a shape substantially tubular with circular cross-section, and is provided with an inlet mouth 9 disposed below the storage member 2 to allow the transfer by gravity of the product 2a. As best illustrated by the constructional detail of Fig. Ia, the conduit 5 is associated with coupling means 10 able to associate the lower end 4b of liner 4 with the conduit 5. In particular, the coupling means 10 exhibit a first device 11 associated with the inlet mouth 9 of conduit 5 for retaining the lower end 4b of liner 4.

Such first retention device 11 is made up of an annular body 12 concentrically disposed around the inlet mouth 9. The annular body 12 defines at least one intake annular ^• groove 13 for aspirating a border of 13a of the lower end 4b of liner 4. In this way, under the operating conditions for the transfer of product 2a (Fig. 5), the lower end 4b of liner 4 is retained onto the outer surface of conduit 5. Also illustrated in Fig. Ia is an intake channel 14 formed in the conduit 5 and developing in correspondence of the annular groove 13. The channel 14 is operatively associated with a pneumatic system (which is not described nor illustrated as being known in the art) able to aspirate the lower end 4b of liner 4, thereby retaining it onto the groove 13.

The annular body 12 further exhibits an air-delivery annular groove 15 interposed between the intake groove 13 and one edge of conduit 5 defining the inlet mouth 9. In particular, the air-delivery annular groove 15 is associated with a respective channel 17 also connected to said pneumatic system. In this way, under the operating conditions for the transfer of product 2a (Fig. 5) , air is

^■diffused within the liner 4 from the air-delivery groove

15. As a consequence, the air spread within the liner 4 prevents possible infiltrations of product 2a into the conduit 5 between the annular body 12 and the liner 4.

The coupling means 10 further exhibit a second retention device 18 movable by suitable driving members (not

^■described) along the longitudinal development of conduit 5. In this way, the second retention device 18 results displaceable close to/away from the first retention deice 11 so as to allow replacing the liner 4 with an exchange liner 4 to be described herebelow in greater detail. In particular, reference being made again to the detailed view of Fig. Ia, the second retention device 18 comprises an annular body 19 concentrically disposed around the conduit 5 and below the first retention device 11. The annular body 19 defines at least one annular groove 20 for aspirating a border 20a of the lower end 4b of liner 4. In this way, as illustrated in Figs. 3 to 5, the border 20a of the lower end 4b is retained and moved close to the first retention device 11.

As above described for the first device 11, the intake annular groove 20 is likewise associated with a channel 21 connected to the pneumatic system to aspirate the border 20a and retain it against the annular body 19 of the second device 18.

As best described later on in relation to the operation of the present apparatus 1, the annular body 19 is movable between a first position where it is a distance away from

'the first device 11 to retain the lower end 4b of an exchange liner 4, and a second position close to the first device 11 to dispose the lower end 4b of the exchange liner

4 onto the first device 11. The coupling means 10 further comprise a clamping element

.22, best visible in the Figs. 1 to 13, moving close to the inlet mouth 9 of conduit 5 for firmly coupling the liner 4 to the same conduit 5.

In greater detail, the clamping element 22 has an annular shape to internally define a hole 22a allowing the liner 4 to pass through (as shown, for example, in Fig. 3) .

,In particular, the clamping element 22 is associated with a respective lifting member 23a consisting, as illustrated by way of example, of two pneumatic pistons able to move the same element 22 close to and away from the conduit 5.

In this way, the element 22 is movable between a first position in which it is associated with the edge 16 of conduit 5 to compress the liner 4 against the same edge 16 (Figs. 4, 5 and 6), and a second position in which it is detached from the edge 16 to remove the liner 4 from the conduit 5 (Figs. 7 to 12).

^•Advantageously, the element 22 exhibits a lower recessed surface 23 which is counter-shaped with respect to the protruding profile of the edge 16 of conduit 5. As a consequence, in the condition in which the clamping element 22 is coupled to the conduit 5, the lower surface 23 is engaged onto the edge 16 to adhere thereon.

The conduit 5 further exhibits an auxiliary tubular liner ^"24, which is inserted into the same conduit 5 to isolate the inner surface from the powdered product 2a.

In other words, the auxiliary liner 24 prevents the powdered product 2a from being contaminated by possible impurities present on the inner cylindrical surface of ■conduit 5. .The liner 24 also prevents the conduit 5 and annular body 12 from being contaminated by the product, thus making unnecessary, in both cases, their cleaning or replacement at the end of campaign, that is, when the last liner 4 has been inserted and the auxiliary liner 24 is to be removed from the apparatus.

Advantageously, disposed on the element 22 is a circular welding means located in the outer face of the lower surface 23 and intended for welding, at the end of campaign, the liners 4 and 24 to be removed in their storage condition, that is, without any contamination from and to the outer environment.

In particular, the auxiliary liner 24 exhibits a top end 24a engaged with the inlet mouth 9 and anchored to an auxiliary annular groove 25 disposed close to the edge 16 Of conduit 5.

•Referring now in particular to Fig. 3, it can be noted that the top end 24a of the auxiliary liner 24 is folded over the edge 16 to cover the latter as far as to lie around the said auxiliary annular groove 25 which results interposed .between the edge 16 and the first retention device 12.

The auxiliary annular groove 25 is also provided with a closing ring 26 inserted into the same auxiliary annular groove 25 in order to firmly anchoring the top end 24a of the auxiliary liner 24. The auxiliary liner 24 further comprises a bottom end 24b connected to the station receiving the product 2a by means, advantageously, of a valve able to be opened and closed under control.

The apparatus 1 further comprises separation means 27 (only schematically shown) disposed between the storage member 2 and the conduit 5.

The separation means 27 exhibit a cutting blade for separating, along the line "X" indicated in Fig. 6, the lower end 4b of liner 4 from the upper end 4a. As best described later on, such cutting operation is carried out upon completion of the discharge of the powdered product

2a.

■Preferably, the separation means 27 consist of a welder intended for dividing the liner 4 and welding the free edges of the ends 4a, 4b thereof thereby avoiding any escape of the powdered product 2a.

Such operation can also be performed by using mechanical spacers such as straps or other elements.

As illustrated in Figs. 2 to 13 which relate to the operating sequences, the liner 4 is associated with the outlet aperture 3 of storage member 2 by means of its upper end 4a (Figs. 1 and 2).

Thereafter, the member 2 is brought in correspondence of the conduit 5 in order to dispose the lower end 4b of liner ^'4 onto the conduit 5.

In particular, as illustrated in Fig. 3, the lower end 4b of liner 4 is fitted onto the inlet mouth 9 of the conduit

5.

'In this situation, the liner 4 is caused to pass through the hole 22a of the clamping element 22 as far as to have the lower end 4b disposed around the first and second retention devices 11, 18.

Under this condition, it can be noted that the second .retention device 18 is disposed a distance away from the first device 11. At this point, the second device 18 aspirates the border

20a to retain the lower end 4b and moves up close to the first device 11.

In addition, during the handling of the second device 18, air is delivered by the first device 11 inwardly of the lower end 4b. In this way, as illustrated in Fig. 4, the lower end 4b is slightly inflated, thereby avoiding the formation of folds in the liner 4.

Subsequently, the clamping element 22 is lowered onto the edge 16 to engage the liner 4 with the conduit 5 (Fig. 5) .

At this point, the first and second retention devices 11,

18, being moved close to one another, provide for

^•aspirating the said borders 13a, 20a of the lower end 4b of liner 4, thereby retaining the liner 4 to the conduit 5. As illustrated in Fig. 5, at this point, it is possible to transfer by gravity the powdered product 2a from the storage member 2 to the inside of tubular liner 4 through

.the conduit 5.

In fact, the liner 4, fixedly anchored to the storage member 2 and conduit 5, ensures the isolation of the product 2a from the external environment, thereby avoiding possible contaminations.

Again, in this stage, air is delivered from the delivery annular groove 15 into the liner 4. Advantageously, the air delivered from the annular groove

15 prevents any infiltrations of product 2a between the liner 4 and the outer surface of conduit 5.

Once the step of transfer of product 2a is completed, the ^' liner 4 must be removed and replaced in order to transfer the product 2a held in a further storage member 2.

In this view, the liner 4 is cut along the line "X" thereby separating the upper end 4a from the lower end 4b.

The cutting operation is performed by said separation means • 27 which provide for cutting and welding the free borders of said ends 4a, 4b (Fig. 6) . The welding can be replaced by a corresponding mechanical locking operation by using straps or other elements. In this situation, it should be noted that the upper end 4a of liner 4 remains associated with the storage member 2 and is removed therewith, while the lower end 4b remains associated with the conduit 5.

Again with reference to Fig. 6, it can be seen that the second retention device 18 is caused to release the border 20a and to move away again. Consequently, the lower end 4b of liner 4 remains retained by only the first device 11.

As illustrated in Fig. I₁ the clamping element 22 is lifted and detached from the conduit 5 to release the lower end 4b still retained by the first device 11. Afterwards, a further storage member 2 is provided which 'holds a respective powdered product 2a. The member 2 is coupled to a respective exchange liner 4' having the same ^•structure as the liner 4 previously described (Fig. 8). The exchange liner 4' is thus fitted onto the conduit 5 as illustrated in Fig. 5, thereby allowing the insertion .therein also of the lower end 4b of liner 4 previously utilized and still anchored to the first retention element

.11-

In this situation, the lower end 4b' of the exchange liner

4' is disposed as above described around the first and second retention devices 11, 18.

It should be noted that the second device 18 provides for sucking and retaining the border 20a' of the exchange liner 4'. Moreover, as illustrated in Fig. 10, the first clutch element 30a of the exchange liner 4' is associated with the second clutch element 30b of the already utilized liner 4. At this point, by putting a hand at least into one of the retractable gloves 8, it is possible to enter the exchange ^'liner 4' for holding and removing the lower end 4b of the already utilized liner 4. Referring now in particular to Fig. 11, it can be noted that the glove 8 actually allows withdrawing manually the lower end 4b of conduit 5, thereby releasing the mouth 9 of the already utilized liner 4.

Advantageously, the clutch elements, coupled to each other 30a, 30b, prevent the lower end 4b of liner 4 already utilized from accidentally falling inside the conduit 5. Thereafter, the glove 8 is taken out of the exchange liner .4' to define said inner chamber 7 (Fig. 12) . Such step is carried out by pulling manually the glove 8 and the lower end 4b of the already utilized liner 4. In this way, the inner chamber 7 results defined and the lower end 4b of liner 4, removed from the conduit 5, can thus be transferred therein. It should also be noted that, in this step, the lower end 4b of liner 4 is disengaged from the first retention device 11.

The suction actuated by the first device 11 is switched into overpressure, thereby facilitating the sliding of the two liners and preventing a contaminating inflow towards the same mouth. The liner 4' is kept engaged during this

^'step by sucking the border 20a from the mouth 20, thereby actually creating a barrier against the outside.

Subsequently, reference being made to Fig. 13, the inner

•chamber 7 containing the lower end 4b of the previous liner 4 is welded or mechanically closed and thus isolated from

•the inner region of the exchange liner 4' . Advantageously, any particles of the product 2a possibly adhering to the lower end 4b within the chamber 7 will be isolated so as not to contaminate a fresh powdered product 2a being transferred through the exchange liner 4' .

In the same manner as above described, the clamping element 22 is again brought onto the edge 16, and the second retention device 18 is moved close to the first device 11 (Fig. 13) . In this way, the exchange liner 4' is anchored to the conduit 5 to allow the transfer of a fresh product within ^•the same conduit 5.

The operation for the exchange of liner 4 can therefore be carried out every time the storage member 2 is replaced. In fact, the handling of the second retention device 18 makes it possible to perform the operation of separation and exchange of liner 4 repeatedly without necessarily engaging a limited number of intake grooves. It should be noted that the second retention device acts onto the exchange liner 4' to retain the same during the removal of the lower end 4b of the already utilized liner 4. Consequently, the re-positioning of the second retention device 18 in the respective condition in which it is moved away from the first device 11, makes it possible to repeat .the exchange operation unlimitedly.

Moreover, the operation of replacing the liner 4 ensures the seal of same liner on the conduit 5 to avoid possible ^'contaminations with the outside. Finally, upon completion of the campaign, that is, when the last liner 4 has been inserted and utilized, the welding machine disposed on the element 22 carries out a welding for the connection between the liner 4 and the auxiliary liner 24. In this way, it results possible to withdraw from below, that is, from the lower part of conduit 5, the auxiliary liner 24 joined to the liner 4 by the said welding. In this way there is obtained, also during the final step of the process, a complete absence of contamination of the apparatus according to the present invention and, therefore, the conduit 5 and annular body 12 are ready for ^■ a new campaign without any need of further cleaning operations .

Claims

1. Apparatus for transferring powdered products, comprising:

- a storage member (2) for storing a powdered product (2a) having a discharge tubular liner (4) extending from a respective outlet aperture (3) for discharging the product (2a);

- a conduit (5) for the passage of the powdered product (2a) having an inlet mouth (9) associable with a lower end (4b) of said liner (4) to allow the transfer of the .powdered product (2a) from the storage member (2) to the conduit (5) ;

- coupling means (10) disposed in said conduit of passage ■(5) for associating the lower end (4b) of liner (4) with said conduit (5) ; separation means (27) disposed between said storage member (2) and said conduit (5) for separating the lower end (4b) of liner (4) upon completion of a discharge .operation for discharging the powdered product (2a); characterized in that said coupling means (10) comprise a first retention device (11) for retaining the lower end (4b) of liner (4) associated with the inlet mouth (9) of conduit (5); and a second retention device (18), movable along said conduit (5) close to/away from the first retention device (11) for replacing the liner (4) with an exchange liner (4') disposed around said liner (4).

^•

2. Apparatus according to the preceding claim, characterized in that said second device (18) is movable between a first position where it is a distance away from ^' the first device (11) to retain the lower end (4b) of the liner (4), and a second position close to said first device (11) to dispose the lower end (4b) of the liner (4) onto the same first device (11) .

3. Apparatus according to any of the preceding claims, ^■ characterized in that said first retention device (11) comprises an annular body (12) disposed concentrically around said inlet mouth (9) of conduit (5) and defining at least an intake annular groove (13) for aspirating a border (13a) of said lower end (4b) of liner (4) in order to retain the same end (4b) against said conduit (5) .

4. Apparatus according to the preceding claim, characterized in that said annular body (12) further comprises an air-delivering annular groove (15), interposed between the intake groove (13) and one edge (16) of conduit (5) defining said inlet mouth (9) to flow air within said liner (4) thereby maintaining the product (2a) inside the conduit (5) .

.

5. Apparatus according to any of the preceding claims, characterized in that said second retention device (18) comprises an annular body (19) disposed concentrically around said conduit (5) to slide along the longitudinal development of the same conduit (5) ; said annular body (19) defining at least one intake annular groove (20) for aspirating a border (20a) of said lower end (4b) of liner ^'(4) to retain the same end (4b) and move it close to said retention device (11) .

6. Apparatus according to any of the preceding claims, characterized in that it further comprises an auxiliary tubular liner (24) disposed within said conduit of passage • (5) and having a top end (24a) engaged with said inlet mouth (9); said top end (24a) being constrained between an auxiliary annular groove (25) being moved close to the edge

(16) of conduit (5) defining said inlet mouth (9), and a

^• closing ring (26) inserted into said auxiliary groove (25) .

7. Apparatus according to the preceding claim, characterized in that said coupling means (10) further comprise a clamping element (22) having annular shape defining a hole (22a) for the liner (4) to pass through; said clamping element (22) being movable between a first position in which it is associated with the edge (16) of conduit (5) defining said inlet mouth (9) to compress the liner (4) against the same edge (16), and a second position in which it is detached from said edge (16) of conduit (5) to disengage the liner (4) from the edge (16).

8. Apparatus according to claim 7, further comprising a welding machine to join said auxiliary liner (24) to the lower end (4b) of said liner (4) so as to carry out their replacement in storage condition at the end of campaign.

9. Apparatus according to any of the preceding claims, characterized in that said liner (4) comprises an upper end

(4a) , opposite to said lower end (4b) , associated with the

^•.outlet aperture (3) of the storage member (2) in order to transfer by gravity said powdered product (2a) ; said liner

(4) also exhibiting at least one hold portion (6) that can be set between a first operating condition in which it protrudes inside the same liner (4), and a second operating condition in which it protrudes outside the liner (4) to define an inner storage chamber (7) .

10. Apparatus according to the preceding claim, characterized in that said hold portion (6) comprises a retractable glove (8) to define said inner chamber (7) ; said inner chamber (7) of the exchange liner (4') containing a lower end (4b) of a liner (4) previously separated.

11. Apparatus according to any of the preceding claims, characterized in that said separation means (27) comprise a welder for separating the lower end (4b) from the upper end ■^' (4a) of liner (4); said ends (4a, 4b) exhibiting a welded edge to avoid any escape of product (2a) from the liner (4).

12. Method for transferring powdered products, comprising the steps of: • - associating an upper end (4a) of a tubular liner (4) with an outlet aperture (3) of a member (2) for storing the powdered product (2a) ; - fitting a lower end (4b) of the liner (4) onto an inlet mouth (9) of a conduit (5) for the powdered product (2a) to pass through;

- engaging the lower end (4b) of liner (4) with respective coupling means (10) disposed within said conduit pf passage

(5);

- transferring by gravity the powdered product (2a) from the storage member (2), through the tubular liner (4), to the inside of the conduit (5); and - subsequently replacing the liner (4) with an exchange 'liner (4') disposed around said liner (4); characterized in that said step of engaging the lower end (4b) of liner (4) is carried out by retaining the lower end (4b) of liner (4) against a first retention device (11) associated with said inlet mouth (9) of conduit (5) and

.against a second retention device (18) movable along said conduit (5) close to/away from the first retention device

(11) •

13. Method according to the preceding claim, characterized ' in that said step of replacing the liner (4) with an exchange liner (4') is carried out by retaining the lower end (4b) of liner (4) by means of the first retention device (11) and retaining the lower end (4b) of the exchange liner (4') by means of the second retention device . (18) .

14. Method according to the preceding claim, characterized in that said step of replacing the liner (4) with an exchange liner (4') further comprises the steps of:

- cutting the liner (4) for separating the upper end (4a) from the lower end (4b) associated with the first retention device (11) ;

^■ - fitting the exchange liner (4' ) over the lower end (4b) of liner (4) ;

- engaging the lower end (4b') of the exchange liner (4') with the second retention device (18); - removing the lower end (4b) of liner (4); and

- engaging the exchange liner (4') with the first retention device (11) .

15. Method according to the preceding claim, characterized in that said step of removing the lower end (4b) of liner

(4) is carried out by the steps of safely engaging the two

.elements (30a) and (30b), then manually withdrawing said lower end (4b) from the inlet mouth (9) of conduit (5), and successively inserting the lower end (4b) of liner (4) into an inner storage chamber (7) formed in the exchange liner

(4') .

16. Method according to the preceding claim, characterized in that said step of withdrawing the lower end (4b) of liner (4) is carried out by means of at least one hold portion (6) shaped as a glove (8) formed in the exchange liner (4') and able to be set between a first operating condition in which it projects inwardly of the exchange liner (4') to grasp the lower end (4b) of liner (4), and a second operating condition in which it projects out of the exchange liner (4') to define the inner storage chamber (7) .

17. Method according to claim 14 or 15, characterized in •that it further comprises the step of sealing the inner chamber (7) following the step of inserting the lower end (4b) of liner (4) .

'18. Method according to any of the preceding claims, characterized in that said step of engaging the exchange liner (4') with the first retention device (11) comprises the steps of: - associating the lower end (4b') of the exchange liner (4') with the second retention device (18) moved away from the first retention device (11) ;

- handling the second device (18) close to the first device ^' (H); - releasing the lower end (4b') of the exchange liner (4') from the second device (18); and

- aspirating from the first device (11) the lower end (4b') of the exchange liner (4').

19. Method according to any of the preceding claims 12-18, further comprising a step of welding said liner (4) to said auxiliary liner (24) to allow removing both liners from the lower part of said conduit (5) .