GB2281548A

GB2281548A - Pneumatic conveyor for cigarette packets

Info

Publication number: GB2281548A
Application number: GB9417106A
Authority: GB
Inventors: Mario Spatafora
Original assignee: GD SpA
Current assignee: GD SpA
Priority date: 1993-09-01
Filing date: 1994-08-24
Publication date: 1995-03-08
Anticipated expiration: 2014-08-24
Also published as: ITBO930355A1; IT1264199B1; GB9417106D0; ITBO930355A0; GB2281548B; DE4429692A1; CN1102391A

Description

1 2281548 CONVEYOR FOR PRODUCTS, PARTICULARLY CIGARETTE PACKETS The

present invention relates to a conveyor for products, particularly cigarette packets.

Reference will be made explicitly hereinafter to products constituted by cigarette packets without thereby losing in generality.

In order to convey cigarette packets it is known to use pneumatic devices which are provided with closed conveyance ducts along which said packets are made to advance by a stream of compressed air which is pumped axially at a relatively high speed inside said conveyance ducts.

The above-described known devices are accordingly of the same kind as those normally used for pneumatic dispatch systems and have the drawback that they do not cushion in any way any collisions between adjacent packets. These collisions become particularly dangerous, and such as to damage the packets, in the case of descending ducts, where the thrust due to gravity combines with the thrust imparted by the air.

The above described disadvantage has so far made it the use of pneumatic conveyors in plants for the manufacture and packaging of cigarettes extremely troublesome., where it is normally necessary to convey the packets above the level of the packaging machines and then make them descend, by means of descending conveyors, until they reach the inlet of said packaging machines.

It would be desirable to be able to provide a conveyor which has a pneumatic descending portion that eliminates the above described drawback.

The present invention provides a conveyor for products.

2 particularly cigarette packets, which has at least one descending portion that comprises a descending pneumatic conveyor, characterized in that said descending pneumatic conveyor comprises a descending conveyance channel whose sectional dimensions are slightly larger than those of the products and in turn comprises a first wall, which has a series of elements for injecting a pressurized pneumatic fluid, and a second wall, which lies opposite to the first wall and has a series of discharge openings which are arranged so that they are axially offset with respect to the related injection elements.

Said descending pneumatic conveyor preferably also comprises a duct which is a delivery duct for a pressurized pneumatic fluid and runs along the channel; the first wall is a wall for separating'the delivery duct from the channel, and the injection elements, which are preferably constituted by simple holes, are formed through said first wall.

The present invention will be described with reference to the accompanying drawings, which illustrate a nonlimitative example of a preferred embodiment thereof, wherein:

figure 1 is a schematic transverse sectional view of an inlet portion _of a preferred embodiment of the conveyor according to the present invention; figure 2 is a schematic transverse sectional view of an outlet portion of the conveyor of figure 1; and figure 3 is a schematic enlarged-scale view of a detail of figure 2.

With reference to figures 1 and 2, the reference numeral 1 generally designates a conveyor for cigarette 3 packets 2 which comprises: an inlet portion, which is formed by a substantially horizontal belt conveyor 3; an ascending portion, which is formed by an ascending pneumatic conveyor 4; an upper intermediate portion, which is formed by an additional substantially horizontal belt conveyor 5; a descending portion, which is formed by a descending pneumatic conveyor 6; and an outlet portion, which is formed by a substantially horizontal belt conveyor 7.

With reference to figure 1, the conveyor 3 comprises a lower belt 8, which winds in a loop around two pulleys 9, only one of which is shown, and an upper presser belt 10 which winds in a loop around three guiding pulleys 11 and has a lower presser segment 12 which faces a terminal outlet portion of an upper suction conveyance segment 13 of the belt 8. The lower segment 12 forms, together with the upper segment 13, a substantially horizontal conveyance channel 14 for the packets 2, which are compressed in contact with the belt 8 by elastic leaf spring-like elements 15 which cooperate with an upper surface of the segment 12.

Again with reference to figure 1, the ascending pneumatic conveyor 4 c.omprises a channel 16 which is substantially S- shaped and in turn comprises a substantially horizontal inlet portion 17, which is aligned with the channel 14, and an equally substantially horizontal outlet portion 18; said portions are mutually connected by an intermediate portion 19 which is inclined upwards. The channel 16 is, in cross-section, slightly larger than the packets 2 and is delimited by an inner wall 20 and by an outer wall 21 which are substantially S-shaped; the first wall has multiple holes 22 which are distributed in a 4 substantially uniform manner along the portions 17 and 19 and form the exit holes for an equal number of injectors 23 for a compressed pneumatic fluid which is preferably constituted by air.

Each injector 23 comprises a duct 24 which is inclined with respect to the channel 16 so that the stream of pneumatic fluid injected by said injector into said channel 16 has a component which is parallel to, and orientated in, a direction 25 along which the packets 2 advance along the channel 16. Each duct 24 runs from an outlet manifold 26 of a centrifugal impeller 27.

With reference to figures 1 and 2, the conveyor 5 comprises a lower belt 28 which winds in a loop around two pulleys 29 and has an upper conveyance segment 30 which is aligned with the upper end of the wall 20. With reference to figure 2, the descending pneumatic conveyor 6 comprises a channel 31 which is substantially S-shaped and which in turn comprises a substantially horizontal inlet portion 32, which is aligned with an outlet portion of the upper segment 30 of the belt 28, and an outlet portion 33, which is also substantially horizontal; said portions are mutually connected by an intermediate portion 34 which is inclined downwards. The cross-section of the channel 31 is slightly larger than the cross-section of the packets 2, and said channel is delimited by an inner wall 35 and an outer wall 36 which are substantially S-shaped; the first wall has multiple injection elements 37 which are distributed in a substantially uniform manner along the portions 34 and 33 to feed a compressed pneumatic fluid, preferably constituted by air, into the channel 31. The wall 36 instead has a series of discharge openings 38 which are arranged along the portions 34 and 33 in an axially offset position with respect to the injection elements 37; the cross-section of each opening is barely sufficient to allow the exit of a flow of pneumatic fluid which is equal to the one injected into the channel 31 by an element 37. In particular, each opening 38 is arranged in an intermediate position with respect to a respective pair of adjacent injection elements 37.

The conveyor 6 furthermore comprises a duct 39 which runs along the channel 31 and is a delivery duct for a pressurized pneumatic fluid which is fed into said duct 39 by multiple ducts 40 which connect an outlet manifold 41 of a centrifugal impeller 42 to points which are substantially uniformly distributed along the duct 39. The duct 39 is separated from the channel 31 by the wall 35 and is connected to said channel 31 by means of the injection elements 37, each one of which is constituted by a respective through hole formed through said wall 35.

At the inlet portion 32, the channel 31 is connected to the duct 39 by means of additional directional injection elements 43 which are orientated in a direction which has a component that is parallel to a direction 44 for the advancement of said packets 2 along said channel 31. Each element 43 comprises an opening 45, which is formed through the wall 35, and a deflector 46, which is arranged outside the channel 31 at the related opening 45 in order to apply said component that is parallel to the direction 44 to a flow of pneumatic fluid that passes through said opening 45. Finally, with reference to figure 2, the conveyor 7 6 comprises a belt 47 with pockets which winds in a loop around two pulleys 48, only one of which is shown; said belt has an upper conveyance segment 49 which is aligned with the lower end of the wall 35.

During use, the packets 2 fed by the belts 8 and 10 into the channel 14 enter the inlet portion 17 of the channel 16 at a relatively high speed which is substantially equal to the advancement speed of the belt 8, and continue by inertia along the portion 17 until they receive the thrust of the compressed pneumatic fluid emitted by the first of the injectors 23. Each packet 2, as it advances along the channel 16, receives the thrusts of the successive injectors 23 and advances along the conveyor 4 due to the same principle that governs pneumatic dispatch systems until it reaches the open end of the outlet portion 18 and is deposited on the upper segment 30 of the belt 28 of the conveyor 5, which feeds the packets 2 in succession to the inlet of the inlet portion 32 of the channel 31.

Once the packets 2 have entered the portion 32 by inertia, they are pneumatically supported by the orientated jets that exit from the injection elements 43 and are pushed by said jets, which are partially orientated in the direction 44, towards the portion 34, along which they descend by gravity until they reach the portion 33 and then the conveyor 7.

With reference to figure 3, by observing what occurs from the point of fluid dynamics inside the portions 34 and 33 of the channel 31, it is evident that the pressurized pneumatic fluid that exits from each element 37 is divided into two parts which run preferentially along respective 7 flow lines 50 and 51 which are substantially sinusoidal and connect said element 37 to the opening 38 which is located directly upstream and to the opening 38 which is located directly downstream in the direction 44. A vortical overpressure region 52 is formed between each pair of flow lines 50 and 51 related to the same element 37; in the same manner, a vortical overpressure region 53 is formed by each pair of adjacent lines 50 and 51 related to two different elements 37. Accordingly, a packet 2 that advances by gravity along the portions 34 and 33 of the channel 31 is subjected to a succession of relatively modest shock waves whose effect is to brake the packet 2 to prevent it from exceeding a set maximum speed which is a function of the speed at which the pneumatic fluid is ejected from the elements 37. The above described braking effect becomes much more intense if a packet 2 moves too close to a packet 2 that precedes it along the direction 44 and advances for any reason along the channel 31 at a speed that is lower than the speed of the packet 2 that follows. In this case in fact the distance that separates the packet 2 that follows from the packet in front of it certainly coincides, at a certain moment, with a portion of the channel 31 where the number of openings 38 is smaller than the number of elements 37 arranged along said portion. When this condition occurs, inside said portion of the channel 31 there is a sharp increase in pressure which tends to equalize the advancement speeds of the two packets 2, reducing substantially to zero the risk of violent impacts between two adjacent packets 2 along the conveyor 6.

In the practical execution of the present invention, 8 the materials employed, as well as the shapes and dimensions, may vary according to the requirements. 0 x k 9 19

Claims

Conveyor for products, particularly cigarette packets, which has at least one descending portion that comprises a descending pneumatic conveyor, characterized in that said descending pneumatic conveyor comprises a descending conveyance channel whose sectional dimensions are slightly larger than those of the products and in turn comprises a first wall, which has a series of elements for injecting a pressurized pneumatic fluid, and a second wall, which lies opposite to the first wall and has a series of discharge openings which are arranged so that they are axially offset with respect to the related injection elements.
2. Conveyor according to claim 1, characterized in that each injection element is arranged in an intermediate position with respect to a respective pair of adjacent discharge openings.
3. Conveyor according to claim 1 and/or 2, characterized In that said descending pneumatic conveyor furthermore comprises a duct which is a delivery duct for a pressurized pneumatic fluid and runs along the channel; said first wall being a separation wall between the delivery duct and the channel; and the injection elements being formed through said first wall.
4. Conveyor according to claim 3, characterized in that each injection element is constituted by a simple hole formed through said first wall.
5. Conveyor according to claim 3 and/or 4, characterized in that said channel is substantially S-shaped and comprises a substantially horizontal inlet portion.
6. Conveyor according to claim 5, characterized in that it comprises additional injection elements which are mounted through said first wall at said first portion and are connected to said delivery duct; said additional injection elements being directional injection elements which are orientated in a direction that has a component which is parallel to a direction for the advancement of the products along the channel.
7. Conveyor according.to claim 6, characterized in that each directional injection element comprises an opening, which is formed through the first wall, and a deflector which is arranged outside the channel at the related opening to apply said component which is parallel to the advancement direction of the products along said channel to a flow of a pneumatic fluid that passes through said opening.
8. Conveyor for products, particularly cigarette packets, substantially as described with reference to any one of the accompanying drawings.