TECHNICAL FIELD
[0001] The present invention relates to a unit for treating containers. In particular, the
invention is directed to a unit for cleaning containers, such as bottles, e.g. in
view of subsequent bottling operations by which bottles are filled with a pourable
product.
[0002] Furthermore, the invention relates to a method for reconfiguring a pre-existing unit
for treating containers so as to become adapted for treating extra-large (namely,
extra-long) containers.
[0003] It is known, for example in the beverage industry, to treat containers needing to
be cleaned, which are most commonly bottles of plastics or glass, with chemicals,
such as caustic solutions, typically in combination with the application of heat.
[0004] To this purpose, use is commonly made of cleaning units wherein bottles are soaked
and sprayed with detergent solutions at a high temperature; rinsed and cooled with
potable water; and, finally, drained. The process is aimed not only at ensuring that
any trace of dirt and any microorganisms possibly present in the bottles be removed,
but also at eliminating from the surface of bottles labels or parts thereof, ideally
without causing their defibration and kneading, which may bring about considerable
drawbacks.
[0005] Composition of the washing cycle, operation modes and temperature, type of washing
solution (acid, alkaline or neutral), etc., all depend on the type of cleaning unit
used, on the degree of dirt of the bottles to be washed, on the features of the water
used and on the pressure of water jets, on the glue used for the labels, on the degree
of concentration of the detergent solutions used, etc. In most cases, however, the
detergent solution used for washing bottles contains, as its main constituent, NaOH,
generally mixed with other alkaline substances or synthetic detergents.
[0006] A longitudinal section of a typical unit 100 for cleaning bottles 101 in a beverage
bottling plant is illustrated schematically in Figure 1. Cleaning unit 100 generally
comprises a plurality of operating stations, namely a pre-treatment station 102, one
or more washing stations 103, a rinsing station 104 and a cooling section 105. Furthermore,
cleaning unit 100 comprises transport means 106 for: receiving the bottles to be cleaned
at an input station 102A; conveying bottles 102 along a bottle path P which crosses
each one of said operating stations; and for delivering cleaned bottles at an output
station 105A.
[0007] Pre-treatment station 102, washing stations 103, and rinsing station 104 all typically
comprise a respective tub, which can be filled with cleaning agents (i.e. the chemicals
in aqueous solution referred to above) for actively washing bottles 102, or water
for rinsing bottles 102 and removing any possible residue of those cleaning agents.
[0008] The speed at which bottles 101 are advanced along path P by transport means 106 is
such that the permanence time of bottles 101 in each tub is enough to achieve the
desired cleaning effect by ensuring a sufficiently prolonged contact with either cleaning
agents or rinsing water.
[0009] Transport means 106 typically consist of a conveyor which comprises a plurality of
bars 107 extending along an axis substantially perpendicular to the plane of Figure
1, each bar carrying a respective plurality of bottle holders 108. Commonly, bottle
holders 108 are in the form of bottle baskets, each of which is adapted to receive
and convey a respective bottle. As they travel across cleaning unit 100, bars 107
are driven, typically by means of a pair of parallel chains arranged about a plurality
of wheels of a relative drive system, along a closed loop which substantially replicates,
in a relative portion connecting input and output stations 102A and 105A, bottle path
P.
[0010] In greater detail, the drive system of cleaning unit 100 comprises: a plurality of
first driving wheels 109A that are, in use, above the level L reached by the detergent/rinsing
solution in the tub of the relative operating stations; and a plurality of second
driving wheels 109B (also referred to, in the following, as "immersed driving wheels")
that are, in use, below the level L reached by the detergent/rinsing solution in the
tub of the relative operating stations. By way of example, each washing station 103
in cleaning unit 100 of Figure 1 has: one first driving wheel 109A arranged above
the surface of the washing bath contained in the relative tub, immediately upstream,
with reference to a direction of advancement of bottles 101 along path P, of the subsequent
operating station; and one second driving wheel 109B arranged below the surface of
the washing bath contained in the relative tub, in an approximately central position
and defining a 180° bend in bottle path P.
[0011] Transport means 106 are continuously cycled through the various parts of cleaning
unit 100 to permit a substantially uninterrupted operation thereof and, thus, an essentially
constant throughput of a substantial number of bottles to meet the needs of high-speed
bottling plants) in certain instances, these machines may process as many as 150,000
bottles per hour).
[0012] Plastic bottles have been for years a popular choice with both manufacturers and
consumers, by virtue of their lightweight nature and relatively low production costs,
compared with glass bottles. The food industry has almost completely replaced glass
with plastic bottles, if not for wine and beer. Bottles made of Polyethylene Terephthalate
(PET, PETE or polyester) are typically used for bottling carbonated beverages, soft
drinks in general, water and many pourable food products. In this context, PET provides
an attractive alternative to glass, because it offers similar size with 75% less material
weight, it is unbreakable and allows the use of larger size containers for carbonated
products with a higher degree of safety. Furthermore, several markets are opening
up to the introduction of extra-large bottle formats which are perceived by consumers
as even more economical. By way of example, plastic bottles taller than 340 mm are
becoming more and more common.
[0013] Bottle washing machines are always designed taking into account the largest bottle
size they will have to handle and the maximum throughput required among the various
bottle sizes. Under all circumstances, a minimum treatment time - i.e. a minimum permanence
time in the washing baths of the machine - must be ensured at all times. Accordingly,
when a washing machine is intended for use with bottles coming in a very wide range
of sizes, it will be designed with a view to meeting the production requirements of
the smallest bottle size, which normally corresponds to the highest throughput.
[0014] However, despite the above-mentioned and widely recognised commercial appeal of extra-long
bottles, cleaning units are not conventionally designed for handling them. In particular,
cleaning units of the known type described above would need to be equipped with correspondingly
extra-large bottle holders, which inevitably would end up interfering with the shafts
of wheels 109 and/or with the walls of the tubs in the various operating stations.
[0015] In order for a cleaning unit of the type described above to be able to accommodate
for extra-large bottles, an overall re-design of the unit would therefore be necessary.
In particular, this would entail re-designing the walls of the tubs of the different
operating stations and, in general, it would result in an increase in the overall
bulkiness of the cleaning unit.
[0016] The cleaning/washing unit is traditionally the most bulky piece of equipment in a
bottling plant. Therefore, an effort is generally made, in the art, to reduce its
overall volume or at least, wherever possible, to avoid a further increase thereof.
[0017] The need is therefore felt, in the art, for a unit for treating containers, in particular
a cleaning unit for use in bottling operations by which bottles are filled with a
pourable product, which makes it possible to treat extra-large bottles whilst substantially
maintaining the overall bulkiness of the cleaning unit unchanged with respect to units
designed for treating smaller bottles.
[0018] In particular, the need is felt in the art for a unit by virtue of which the cleaning/washing
operations of larger-size bottles may be carried out reliably and safely without needing
to alter the design of the tubs of the different operating stations in the cleaning
unit, in particular without needing to increase their overall volume.
[0019] It is an object of the present invention to provide a unit for treating containers,
particularly for cleaning containers in beverage bottling operations, which makes
it possible to meet the above needs in a straightforward and low-cost manner. This
object is achieved by a unit as claimed in Claim 1.
[0020] Furthermore, the invention provides a method for reconfiguring a pre-existing unit
for treating containers so as to become adapted for treating extra-large containers,
in accordance with Claim 2.
[0021] Further features and advantages of the present invention will be better understood
from the description of a preferred embodiment, which is given below by way of a non-limiting
illustration, with reference to the accompanying drawings, in which:
Figure 1 shows a schematic longitudinal section of a known unit for cleaning bottles
in a beverage bottling plant;
Figure 2 shows a schematic longitudinal section of a unit for cleaning bottles in
a beverage bottling plant according to the invention; and
Figure 3 shows a larger scale view of a detail of Figure 2.
[0022] In Figure 2, a cleaning unit 100' of the type commonly forming part of a beverage
bottling plant, which was briefly described above with reference to Figure 1, is illustrated.
[0023] For the sake of conciseness and simplicity, the description given in the following
of cleaning unit 100' shall not cover in detail certain constructional aspects which
virtually reproduce corresponding features already described above with reference
to cleaning unit 100 according to the prior art. Therefore, wherever possible, when
describing cleaning unit 100', the same reference numbers shall be used for parts
that are identical or functionally alternative to corresponding parts of cleaning
unit 100 described above.
[0024] Cleaning unit 100' comprises a plurality of operating stations, including at least
one washing station 103, a rinsing station 104 and a cooling section 105. Furthermore,
cleaning unit 100' comprises transport means 106 for: receiving the bottles to be
cleaned at an input station 102A; conveying bottles 102 along a bottle path P which
crosses each one of said operating stations; and for delivering cleaned bottles at
an output station 105A.
[0025] The one or more washing stations 103 and the rinsing station 104 comprise respective
baths 103B, 104B, wherein bottles 101 are brought into contact with cleaning agents
(i.e. the chemicals in aqueous solution referred to above) and rinsed for removing
any possible residue of those chemicals.
[0026] Each bath 103B, 104B is delimited by suitably shaped walls 103W, 104W which are configured
and arranged to hold a liquid medium - namely the cleaning solution, or rinsing water
- and are so designed to accommodate for the bends and turns in bottle path P.
[0027] For a better understanding, in Figure 2, the volume occupied, in use, by either detergent
solution or rinsing bath has been highlighted by colouring the relative cross section
in grey.
[0028] In practice, at least in one washing station 103, bath 103B (namely, walls 103W)
is (are) defined by a number of substantially non-deformable metallic elements (e.g.
sheets) and comprises at least one substantially horseshoe-shaped recess 110 for receiving
and lodging an immersed driving wheel 109B of transport means 106, whereby the direction
of advancement of bottles within bath 103B, in use, is varied. In particular, in the
embodiment of Figure 2, the direction of advancement of bottles 101 within bath 103B
is varied of 180° or more as they travel about the relative wheel 109B.
[0029] In greater detail (reference may conveniently be made to Figure 3), horseshoe-shaped
recess 110 comprises a substantially semicircular portion 111, the outer diameter
D
B of immersed wheel 109B substantially matching the diameter D
SC of semicircular portion 111. In other words, immersed wheel 109B is lodged with a
slight play in recess 110.
[0030] Furthermore, washing station 103 comprises one driving wheel 109A which is arranged
above the surface of the detergent solution contained in bath 103B.
[0031] In the embodiment shown in Figure 2, at driving wheel 109A the direction of advancement
of the bottles in washing station 103 is varied from a substantially vertical direction
to a substantially horizontal direction, i.e. the bottles are received by wheel 109A
as they rise from a bottom portion of bath 103B towards and above its surface and
they are delivered on to the next operating station at an exit of washing station
103.
[0032] Many alternative layouts can be considered for bottle path P. However, in order for
the bottles to have, in each bath 103B, 104B, a permanence time which is enough to
achieve the desired cleaning effect, bottle path P is generally designed in an attempt
to maximise a path-length to bath-volume ratio, which results in bottles 101 changing
direction several times between an entrance and an exit of each operating station,
let alone between input station 102A and output station 105A of cleaning unit 100'.
Besides, the speed at which bottles 101 are advanced along bottle path P by transport
means 106 is set such that the permanence time of bottles 101 in each bath is enough
to achieve the desired cleaning effect.
[0033] By way of example, in the embodiment illustrated in Figure 2, the bottles coming
from input station 102A and being held, upon reaching washing station 103, head first
- i.e. with the opening facing downwards - are conveyed by transport means up and
down within the relative bath 103B and then extracted from the same bath 103B, whereby
the inclination of bottles 101 in space and their local direction of advancement undergo
several major modifications, so as to carry out different operations concurring to
completion of a cleaning process.
[0034] Bottle cleaning, in fact, typically involves three stages: first, bottles 101 are
soaked in a bath, whereby dirt is chemically attacked by the caustic action of soda,
increased by high temperature; secondly, bottles 101 are emptied to remove the dissolved
dirt and used detergent solution; finally, the mechanical action of jets directed
to the inside of bottles 101 is resorted to for removing the dirt that has been chemically
attacked and yet has stuck to the bottle inner wall.
[0035] To this purpose, following the washing operation carried out in the one or more washing
station 103, bottles 101 are moved on to rinsing station 104, which may include an
immersion zone, followed by a spray-cooling section 105.
[0036] As bottles 101 travel across rinsing station 105, temperature is gradually lowered
and the detergent solution is removed from both bottles 101 and transport means 106.
The water employed for rinsing is conveniently recovered to the pre-treatment section.
[0037] Transport means 106 typically consist of a conveyor comprising a plurality of bars
(not shown) extending along an axis substantially perpendicular to the plane of Figure
1, each bar carrying a respective plurality of bottle holders 108. Commonly, bottle
holders (not illustrated in Figure 2) are in the form of bottle baskets, each of which
is adapted to receive and convey a respective bottle, as shown in Figure 1. As the
bars 12 travel across cleaning unit 100', the bars are driven by a pair of parallel
chains arranged about respective drive systems, along a closed loop path. The closed
loop path connects input and output stations 102A and 105A. In particular, these drive
systems are motorised via first and second driving shafts 112A, 112B, bearing driving
wheels 109A and 109B, respectively.
[0038] Advantageously, in cleaning unit 100', driving wheels 109B have (see also Figure
3) a diameter D
B - which is slightly smaller than the diameter D
SC of the semicircular portion 111 of "U"-shaped recess 110. The diameter of the driving
wheels 109B is also smaller than the diameter DA of the driving wheels 109A'. Driving
wheels 109B are supported on the second driving shaft 112B, which have a diameter
dB that is smaller than the diameter d
A of first driving shafts 112A. The difference (D
SC - d
B) being substantially equal to the difference (D
A - d
A) and to twice the height H of bottles 101 to be treated.
[0039] Certain driving wheels 109B of transport means 106 are housed within a space that
is delimited by the inner surface of the "U"-shaped wall of bottle washing station
103. Therefore, when longer bottles have to be accommodated between the respective
driving shaft 112B having diameter dB and the inner surface of the "U"-shaped wall,
diameter dB of driving shaft 112B is reduced. This inward reduction of shaft diameter
avoids the need for outward increase in the size of the "U"-shaped wall of the bottle
washing station 103, and consequently, advantageously avoids the need to increase
the external dimensions of the entire unit. This is possible because the shaft 112B
having diameter dB is subjected, in use, to only a low level of torque.
[0040] The other shafts, such as the shaft dA of driving wheel 109A, are subjected to higher
torque forces. Consequently, the diameter dA of the respective shaft 112A is greater
than the diameter dB of the shaft 112B of driving wheel 109B. Therefore, in order
to transport longer bottles, the diameter DA of driving wheel 109A is increased. This
increase in the diameter DA of driving wheel 109A is necessary, since the diameter
dA of driving shaft 112A cannot be reduced due to the higher torque forces that act
on it during operation.
[0041] In other words, when the diameter dB of driving shaft 112B of driving wheel 109B
is reduced to accommodate bottles of greater length, within the confines of the "U"-shaped
wall of the transport system, the outer diameter DA of the successive driving wheel
109A is increased. This enables longer bottles to be treated, without increasing the
external dimensions of the bottle treating unit.
[0042] In particular, when the need arises to reconfigure a pre-existing cleaning unit 100'
comprising at least one washing station 103 with a bath 103B comprising at least one
substantially horseshoe-shaped recess 110 for receiving and lodging an immersed driving
wheel 109B, the diameter DB' of immersed wheel 109B substantially matching the diameter
DSC of a semicircular portion 111 of horseshoe-shaped recess 110; wherein all driving
wheels 109A, 109B all have the same diameter DA'=DB' and are borne by respective driving
shafts 112A, 112B all having the same diameter dA'=dB'; the cleaning unit 100' needing
to be reconfigured so that it can accommodate bottles 101 having a height H greater
than the diameter difference between immersed wheels 109B and the respective driving
shafts, i.e. a height H greater than (DB'-dB')/2; the size of driving wheels 109A,
109B and of the relative driving shafts 112A, 112B may advantageously be modified
so that the diameter DA of the driving wheels 109A which are arranged above the surface
of the liquid media in the baths of cleaning unit 100' is greater than the diameter
DB' of immersed driving wheels 109B; immersed driving wheels 109B being borne by second
driving shafts 112B having a diameter dB smaller than the diameter dA of first driving
shafts 112A; the difference (DSC - dB) being substantially equal to the difference
(DA - dA) and to twice the height H of bottles 101 to be treated.
[0043] The advantages of the unit and method according to the present invention will be
clear from the above description.
[0044] In fact, when faced with the need to reconfigure a pre-existing cleaning unit 100
so that it can conveniently process longer bottles, reducing the diameter of all driving
shafts 112A, 112B by a length such as to accommodate extra-large bottle holders might
appear to be a practical solution.
[0045] However, smaller shaft diameters are generally not compatible with the loads to which
the driving wheel shafts are subjected, in operation. In fact, under these circumstances,
shafts are required to bear loads larger than the usual ones, because extra-large
bottles are even heavier, when filled, than average-sized bottles.
[0046] On the other hand, shifting bottle holders 108 to a radially outer position relative
to the driving wheel shaft, and therefore increasing the diameter of immersed driving
wheels 109B, could be an appealing alternative design option, yet it would require
a complete re-design of the whole cleaning unit 100, especially as far as shape and
size of the tubs of the different operating stations are concerned. In practice, this
approach would be greatly disadvantageous, because it would entail a much too dramatic
intervention on cleaning unit 100, whereby the geometry of the tubs of the baths 103B
would have to be redesigned in its entirety, with an eventual and unavoidable increase
of the overall bulkiness to make room for a greater distance between bottle holders
108 and their rotation axis.
[0047] The solution of the invention, on the contrary, provides for a rather straightforward
and relatively inexpensive solution for accommodating longer bottles without having
to redesign and increased the bulkiness of baths 103B of washing stations 103.
[0048] Clearly, changes may be made to the unit and method as described and illustrated
herein without, however, departing from the scope of protection as defined in the
accompanying claims.