Apparatus for cleaning inside and outside surfaces of containers

Apparatus for cleaning open-mouthed cylindrical containers has a plurality of pot assemblies mounted on a turntable rotatable to move each pot assembly past an unloading station for discharge of containers from the pot assemblies and a loading station for insertion of containers into the pot assemblies. Each pot assembly comprises a body co-operating with a lid to define a cavity for reception of a container, the cavity having a shape corresponding approximately to that of the container and having a size such that the container subdivides the cavity into two chambers in which the walls of the cavity are spaced close to the inside and outside surfaces of the container. Cam rollers on each pot assembly co-operate with cam tracks, upon rotation of the turntable, to open the lid immediately prior to passage past the unloading station and to close the lid immediately after passage past the loading station. During passage between the loading and unloading stations cleaning liquid is circulated through the chambers, the liquid flowing along the inside and outside surface of the container to clean the surfaces. The liquid flows at high speed due to the small volume of the chambers. Rinsing water is then circulated through the chambers, and finally drying fluid to dry the container before discharge at the unloading station.

This invention relates to the cleaning of containers or jars, and is 
concerned more particularly but not exclusively to the cleaning of 
open-mouthed metal containers of the kind comprising a cylindrical body 
open at one end and closed at the other end by a circular disc which may 
either be flat or contoured to provide resistance to internal pressure. 
Metal containers of this kind are commonly used for the packing of aerated 
beverages and they are often made by drawing in a single piece. The action 
of drawing involves the use of lubricants which have to be completely 
removed before such containers can be used for food packaging or be 
satisfactorily printed on the outside for display purposes. 
It is normal practice for such containers to be cleaned by placing them on 
a conveyor and subjecting them to high pressure sprays of detergent water 
followed by sprays of washing water, followed by a period of draining and 
drying by means of hot air circulation. 
When such containers are made from aluminium it is sometimes desirable to 
.[.includes.]. .Iadd.include .Iaddend.a dilute acid treatment to etch the 
surface for improved ink adhesion when the containers are decorated. 
As the whole process of washing and drying is carried out by randomly 
disposed liquid and air jets, the duration of the cycle has to be 
prolonged to ensure complete washing and drying of all parts of all 
containers. Such conveyor systems when designed for high volume production 
are massive and very costly involving the use of considerable heat and 
mechanical energy. 
An alternative method is to pass the conveyor system through a degreasing 
tank containing trichlorethylene vapour prior to drying by hot air 
circulation. 
Such equipment though less costly and more compact has a disadvantage that 
stoppages due to malfunction of the mechanism are difficult to deal with 
on account of toxicity of the degreasing fluids and vapours freely 
circulating within the cleaning apparatus. 
The object of the invention is to provide an improved method and apparatus 
for cleaning a container which is not subject to the above disadvantages. 
According to the invention there is provided a method of cleaning an 
open-mouthed container, comprising mounting the container in a cavity in a 
body, the cavity having a shape corresponding approximately to that of the 
container with the walls of the cavity spaced close to the surfaces of the 
container, and the container subdividing the cavity into two chambers, and 
passing a cleaning fluid through the chambers so that the cleaning fluids 
fills the chambers and flows along the surfaces of the container. 
The method of the invention enables containers to be cleaned thoroughly in 
a precisely controlled manner at high speed with the minimum consumption 
of cleaning fluid. 
Turbulence is preferably induced in the fluid flowing through the chambers 
in order to improve the cleaning action of the fluid on the container, for 
example by passing the fluid across roughened or grooved surfaces in the 
cavity. 
The container can conveniently be dried immediately after cleaning by 
passing a drying fluid, for example hot air, through the chambers. 
According to the invention there is also provided apparatus for cleaning an 
open-mouthed container of a given size, comprising a pot assembly having a 
body and a lid defining a cavity for reception of the container, the lid 
being movable into an open position to permit introduction of the 
container into the cavity, means for centering the container in the 
cavity, the cavity having a shape corresponding approximately to that of 
the container and a size such that the container subdivides the cavity 
into two chambers in which the walls of the cavity are spaced close to the 
inside and outside surfaces of the container, and conduit means for 
passing cleaning fluid through said chambers so that the cleaning fluid 
fills the chambers and flows along the inside and outside surfaces of the 
container. 
The apparatus of the invention can readily be adapted to operate 
automatically or semi-automatically, by providing a plurality of pot 
assemblies as defined above supported on a turret rotatably mounted on a 
frame, drive means operable to rotate the turret so that each pot assembly 
passes in succession past a container unloading station and a container 
loading station, and lid control means operable to move the lid of each 
pot assembly into the open position immediately prior to passage of the 
pot assembly past the unloading station and to move the lid into the 
closed position immmediately after passage of the pot assembly past the 
loading station, and valve means for regulating flow of fluids through 
said conduit means and chambers only during passage of each pot assembly 
between the loading station and the unloading station.

The apparatus shown in FIGS. 1-7 comprises a circular base plate 10 having 
a peripheral wall 11, a vertical spindle 12 secured to the centre of the 
base plate, and a turret 14 rotatably mounted by bearings 15, 16 on the 
spindle. The turret comprises a hub 17 on which the bearings are mounted, 
and a circular top plate 19. The bearings 15, 16 are held in position by a 
nut 21 screwed on the spindle. A cylinder 25 co-axial with the spindle 12 
is secured to the underside of the top plate 19, the lower end portion of 
the cylinder 25 being formed with teeth 26 which mesh with a pinion 27 
rotatable by drive mechanism (not shown) for turning the turret. The top 
plate 19 is fitted with 24 pot assemblies 28 for reception of the 
containers to be cleaned, and a manifold ring 29 connected by flexible 
pipes 30, 31 to the pot assemblies for conveying cleaning, drying and 
operating fluids to and from the pot assemblies. A plate 32 on the top of 
the spindle 12 supports a distributor ring 33 for feeding fluid into and 
away from the manifold ring. 
Each pot assembly 28 comprises a support plate 36 (FIG. 3) secured to the 
top plate 19, an upright cylindrical shell 38 mounted on the plate 36, the 
top of the shell being open and the bottom having an end wall 39 formed 
with a central aperture 40, a centering ring 41 mounted in the shell on 
the end wall 39, and a cylindrical core 42 mounted in the shell on the 
ring 41, the bottom of the core having a spigot 43 which extends as a 
close fit through the ring 41 and the aperture 40, and the bottom of the 
spigot being seated in a recess in the support plate 36. Screws 45 on the 
plate 36 extend upwards through apertures in the end wall 39 and ring 41 
and are screwed into the core, thereby securely clamping the components 
together. The core 42 cooperates with the shell 38 to form a cavity 46 for 
the reception of a container 47 to be cleaned. A recess is formed in the 
top of the core 42 at the centre thereof, and an outlet duct 49 extends 
from the recess downwards through the core and spigot 43 and connects with 
a further duct 50 in the support plate 36. Sealing rings 51, 52 are 
mounted in grooves in the bottom surfaces of the shell 38 and spigot 43 
respectively. The centering ring 41 has an outer wall which is aligned 
with the outer wall of the core, and the ring 41 is provided with axially 
extending fins 54 spaced around the ring, the upper ends of the fins being 
chamfered and adapted to engage inside the mouth of a container fed 
open-end downwards onto the core so as to centre the container on the core 
and each fin is formed with a ledge 55 for support of a container. The 
inside surface of the upper end part of the shell is convex as shown at 
56, and the inside surface of the shell immediately below the convex 
surface 56 is tapered downwardly as shown at 57, the remainder of the 
inside surface of the shell being cylindrical. The cylindrical inner 
surface of the shell 38 and the opposing outside surface of the core 42 
are formed with a screw thread as shown in FIG. 4. 
Each pot assembly includes a lid 58 consisting of a cover plate 60, a crown 
61 located in a recess in the underside of the plate 60 and having an 
annular peripheral flange 63 formed with a downwardly projecting lip 64, 
the crown being secured to the plate 60 by screws 65, and an annular 
sealing member 66 having a radial wall 67 clamped between the flange 63 
and the cover plate 60, and a cylindrical wall 68 extending downwards 
below the lip 64. The crown 61 is formed with a central aperture 70 
aligned with an aperture 71 in the plate 60, the upper portion of the 
aperture 70 being enlarged to form a valve chamber 72 housing a valve 
member 73 having a stem 74 slidably mounted in the lower portion of the 
aperture 70. The valve member is adapted to block flow of fluid through 
the apertures 70, 71 when in a closed position in which it is engaged 
against the bottom wall 75 of the valve chamber, and the valve member is 
biased towards the closed position by a spring 76 compressed between the 
valve member and a tubular pipe connector 77 screwed into the aperture 71 
in the plate 60. The stem 74 is of triangular cross section with recessed 
walls to permit fluid to flow past the stem in the aperture 70 when the 
valve member is in an open position spaced from the wall 75 of the valve 
chamber. The stem 74 has a length such that, when the valve member is in 
the closed position, the stem extends across the gap between the crown 61 
and the core 42 and projects into the recess 48 in the top of the core. 
The cover plate 60 is rigidly secured to a sleeve 80 mounted on a vertical 
shaft 81 which is in turn mounted in a bush 82 secured in an aperture in 
the support plate 36. The lower end portion of the sleeve 80 has an 
inwardly projecting step 83 which is a close sliding and rotational fit on 
the shaft, and the upper end of the shaft is fitted with a head 84 which 
is a close sliding and rotational fit inside the upper end portion of the 
sleeve 80. The head 84 is secured to the shaft by a screw 85 and pin 86. 
The upper end of the head 84 is formed with a conical spigot 87 adapted to 
engage in a conical socket 88 in a ring 89 screwed into the upper end of 
the sleeve 80. A coil spring 90 is compressed between the step 83 and the 
head 84, the spring urging the sleeve downwards to engage the conical 
socket 88 on its spigot. The lower end of the sleeve 80 is formed with two 
rectangular teeth 91 which engage in corresponding recesses 92 in the 
upper end of the bush 82 when the lid 58 is in the closed position, as 
shown in FIG. 3. The teeth 91 and recesses 92 form alignment means which 
prevent the lid being moved into its closed position except when the lid 
is at a predetermined angular setting relative to the shaft. It will be 
appreciated that upward movement of the shaft will lift the sleeve and 
cover plate 60 and thereby lift the lid of the pot assembly above the 
shell 38. Rotational movement of the shaft will then swing the lid 
laterally away from the shell 38, the torque being transmitted between the 
shaft 81 and the sleeve 80 by the frictional resistance between the 
conical spigot and socket 87, 88. 
The lower end of the bush 82 projects through an aperture in the top plate 
19 of the turret, and the shaft 81 extends downwards below the turret and 
is fitted with a cam roller assembly 95 which co-operates with a 
horizontal cam track 96 and a vertical cam track 97 mounted on the base 
plate. The roller assembly comprises a block 98 secured on the bottom of 
the shaft 81, a roller 100 rotatably mounted on a horizontal spindle 101 
secured to the block 98, and a roller 102 rotatably mounted on a vertical 
spindle 103 projecting downwards from the block 96, the axis of the roller 
102 being offset from the axis of the shaft 81. The spindle 103 extends a 
short distance below the roller 102 for a purpose explained hereinafter. 
The roller 100 is adapted to engage in the horizontal cam track 96 and the 
roller 102 is engaged in the vertical cam track 97. 
The horizontal cam track 96 is formed by a channel shaped slot in the 
outside wall of an arcuate rail 105 which extends around approximately 270 
degrees of the base plate, and two further slots in the outside walls of 
two cam blocks 106, 107 arranged one at each end of the arcuate rail, the 
roller 100 being a running fit in the slots. The centre line of the cam 
track in the rail 105 remains at a constant level indicated at A in FIG. 
1. The cam track in the block 106 is arranged to lift the roller 100 up to 
the level B shown in FIG. 1. As shown in FIG. 6, the cam track in the 
block 107 is arranged to receive the roller 100 at the level B and lower 
the roller down to the level A. 
The vertical cam track 97 comprises a channel spaced slot formed in the top 
surfaces of two arcuate rails 110, 111 and in the top surfaces of two cam 
blocks 112, 113 interposed between the ends of the rails 110, 111, the cam 
track extending continuously around the base plate. The rail 110 extends 
around an arc equal to that subtended by the rail 105 and cam blocks 106, 
107 and the centre line of the cam track in rail 110 is at a constant 
radiius C (FIG. 1) from the axis of the turret. The base of the cam track 
on the part of the rail 110 surrounding rail 105 is at a level such that 
it is below the bottom end of the spindle 103 of the roller assembly 95, 
the height of the spindle 103 being of course determined by the roller 100 
in the cam track 96 in rail 105, but the base of the cam track on the part 
of the rail 110 opposite cam block 106 rises to a level such that it is 
immediately below the bottom of the spindle 103. The centre line of the 
cam track in rail 111 is at a constant radius D (FIG. 1) from the axis of 
the turret and the base of the track is at a level such that, when the 
spindle 103 of the roller assembly rests on the base, the axis of the 
roller 100 is at the level B shown in FIG. 1. The cam tracks in the blocks 
112, 113 form continuations of the cam tracks in the rails 110, 111 and, 
as shown in FIG. 2, are arranged so that a roller 102 rolling around the 
cam track in an anticlockwise direction is moved inwardly from radius C to 
radius D (FIG. 1) during passage along block 112 and moved outwardly from 
radius D to radius C during passage along block 113. 
The manifold ring 29 is provided with a separate pair of ducts 120, 121 for 
each pot assembly 28, each duct 120 being connected by a flexible pipe 30 
to the connection 77 on the associated pot assembly and each duct 121 
being connected by a pipe 31 to the duct 50 in the associated pot 
assembly. The ducts 120, 121 open through the top surface of the ring 29, 
the ends of the ducts 120, 121 lying respectively in two common circles 
concentric with the turret axis. The distributor ring 33 is slidably 
mounted on vertical pillars 124 secured to the plate 32 and is urged 
downwards by coil springs 125 on the pillars into sliding contact with the 
top surface of the manifold ring. As shown in FIG. 7 the underside of the 
distributor ring is formed with a first pair of arcuate grooves 126a, 126b 
for circulating cleaning fluid through the pot assemblies, a second pair 
of arcuate grooves 127a, 127b for circulating rinsing water through the 
pot assemblies, a third pair of arcuate grooves 128a, 128b for circulating 
hot air through the pot assemblies, and two arcuate grooves 128a, 128b for 
circulating hot air through the pot assemblies, and two arcuate grooves 
129, 130 for applying compressed air and vacuum respectively to the pot 
assemblies. The grooves 126a, 127a, 128a are all arranged on a common 
circle and adapted to register in succession with each of the ducts 120 
upon rotation of the manifold ring with the turret, and the grooves 126b, 
127b, 128b, 129, 130 are all arranged on a common circle and adapted to 
register on succession with each of the ducts 121 upon rotation of the 
manifold ring with the turret. All the arcuate grooves are connected 
through openings in the top of the distributor ring to pipes 132 for 
supplying and exhausting the fluids from the grooves. 
In operation, the turret is rotated continuously by the pinion 27 in an 
anti-clockwise direction as shown in FIG. 2. When each pot assembly 
reaches the cam block 106, its roller 100 rides up the cam track 96 and 
thereby lifts the shaft 81, sleeve 80 and cover plate 60 so as to lift the 
lid 58 of the pot assembly. The roller 100 rides out of the track 96 at 
the end of the cam block 106 but the lid is held in the raised position by 
engagement of the spindle 103 on the base of the cam track 97 during 
movement of the pot assembly the cam blocks 106, 107. When the pot 
assembly reaches the block 107 the roller 100 enters the cam track 96 as 
shown in FIG. 5, the track 96 in block 107 forcing the shaft 81 downwards 
to close the lid. In the event of downward movement of the lid being 
obstructed, for example by a misplaced container in the pot assembly, the 
shaft 81 will merely slide within the sleeve 80 and compress the spring 
90. 
When each pot assembly reaches the cam block 112, the cam track 97 causes 
the roller 102 to move radially inwards and thereby causes the block 98 
and shaft 81 to pivot in a clockwise direction as shown in FIG. 2, thereby 
moving the lid radially inwards to uncover the cavity in the pot assembly. 
The lid remains in the open position until the post assembly reaches the 
cam block 113, whereupon the cam track 97 therein causes the roller to 
move radially outwards and cause the block 98 and shaft 82 to swing the 
lid outwards over the pot assembly. It will be appreciated that, since the 
pot assembly reaches the cam block 106 before the cam block 112, the 
roller 100 will raise the lid to withdraw the crown 61 and seal 66 from 
the top of the shell 38 before the roller 102 causes the lid to swing 
inwards. Similarly, since the pot assembly reaches the cam block 113 
before the cam block 107, the roller 102 will cause the lid to swing 
outwards to a position above the shell 38 before the roller 100 lowers the 
lid. 
In the event of radial inwards or outwards movement of the lid being 
obstructed, the turning force exerted by the roller 102 on the shaft 81 
will overcome the frictional force between the conical spigot and socket 
87, 88 so that the shaft will turn relative to the sleeve 80. The lid will 
then be displaced relative to the shaft 81, that is the lid will no longer 
be at the previously mentioned predetermined angular setting relative to 
the shaft, and if the shaft is then drawn down by the roller to close the 
lid, the teeth 91 on the sleeve 80 will abut against the top of the bush 
82 and prevent the sleeve 80 being drawn down with the shaft. In order to 
centralise the lid relative to the shaft 81 after an obstruction has 
caused relative movement therebetween, the support plate 36 of each pot 
assembly is provided with an abutment post 136 to abut the lid at its 
radially innermost position and the cover plate 60 of the lid is provided 
with a downwardly projecting lug 137 arranged to abut the shell 38 at the 
radially outermost position of the lid. 
Mechanism (not shown) for receiving containers discharged from the pot 
assemblies is provided at an unloading station X alongside the rail 111 
and mechanism (not shown) for introducing containers into the pot 
assemblies is provided at a loading station Y alongside the rail 111. 
These mechanisms can be of any suitable construction known in the art. The 
lid of each pot assembly is of course in the fully open position during 
passage of the pot assembly along the rail 111. The distribution ring 33 
is arranged so that the ducts 121 in the manifold ring register with the 
compressed air groove 129 during passage of the associated pot assembly 
past the unloading station X and register with the vacuum groove 130 
during passage of the associated pot assembly past the loading station Y. 
One operating cycle for a pot assembly in which it travels from the loading 
station Y around the apparatus to the unloading station X upon rotation of 
the turret through one revolution will now be described. 
When the pot assembly is in register with the loading station, the lid is 
fully open and the ducts 49, 50 are connected through pipe 31 and duct 121 
to the vacuum groove 130. The loading mechanism feeds a container open-end 
downwards into the cavity 47, and the vacuum in duct 49 causes air to be 
drawn into the duct and thereby draws the container downwards onto the 
ledges 55 on the fins 54. The lid then closes as the pot assembly travels 
past the cam blocks 113, 107. As shown in FIG. 3 the core 42 and shell 38 
have a shape corresponding to that of the container and are of a size such 
that the container is spaced from the core and shell and subdivides the 
cavity therebetween into an inner chamber between the core and container 
and an outer chamber between the shell and container. The two chambers are 
of the minimum practical width, for example 0.015 inches, and should 
preferably not exceed 0.15 inches. The inner chamber is in direct 
communication through ducts 49, 50 and pipe 31 with the duct 121 in the 
manifold ring. The base of the container bears against the valve stem 74 
and holds the valve 73 open, as shown in FIG. 3, so that the outer chamber 
is in direct communication through apertures 70, 71 and pipe 30 with the 
duct 120 in the manifold ring. 
When the ducts 120, 121 associated with the pot assembly register with the 
arcuate grooves 126a, 126b, cleaning liquid from groove 126a enters the 
top of the outer chamber, flows down the sides of the outer chamber, 
through the slots between the fins 54, up the sides of the inner chamber, 
across the top of the inner chamber, and back to the groove 126b through 
the duct 49. The liquid completely fills the two chambers and, due to the 
very narrow .[.wifth.]. .Iadd.width .Iaddend.of the chambers, travels at a 
fast speed across all the surfaces of the container. The screw thread on 
the walls of the core and shell cause turbulence in the liquid and thereby 
ensure the maximum cleaning effect on the surfaces of the container. 
Instead of providing screw threads on the core and shell, these parts may 
be shot blasted or otherwise roughened so as to cause turbulence in the 
liquid. Alternatively, air may be introduced into the liquid, conveniently 
in the feed pipe to the pump for the liquid, to form bubbles which will 
cause turbulence in the liquid in the chambers. 
Rinsing water will flow through the two chambers when the ducts 120, 121 
register with the grooves 127a, 127b in the distributor ring, and hot air 
will flow through the two chambers to dry the container when the ducts 
120, 121 register with the grooves 128a, 128b. The lid then opens as the 
pot assembly travels past the cam blocks 106, 112. When the pot assembly 
arrives at the unloading station the duct 121 registers with the groove 
129 in the distributor ring and compressed air from the groove 129 enters 
the inner chamber and ejects the container from the pot assembly and into 
the unloading mechanism. 
If any of the pot assemblies is not loaded with a container at the loading 
station, the valve 73 will remain engaged against the wall 75 and prevent 
entry into the cavity of the cleaning or rinsing fluids. 
When the lid is closed on each pot assembly its lip 64 clamps the 
cylindrical wall 68 of the resilient sealing member against the convex 
surface 56 on the shell to provide a fluid tight fit. Moreover, since the 
wall 68 projects below the lip, fluid pressure in the outer chamber forces 
the wall 68 against the convex surface to provide an additional safeguard 
against leakage of liquid. 
The apparatus described above is particularly suitable for use in cleaning 
containers with trichlorethylene or other highly toxic liquids or vapours, 
since the cleaning fluid flows in closed circuits. 
FIGS. 8, 9, 10 show alternative constructions of pot .[.assmblies.]. 
.Iadd.assemblies .Iaddend.which could replace the pot assemblies 38 in 
apparatus adapted to accommodate them, and like parts are indicated by 
like reference numerals. 
The pot assembly of FIG. 8 has an outer shell .[.158.]. .Iadd.138 
.Iaddend.formed integral with the cover plate 60 of the lid, the bottom of 
the shell being open so that the inner and outer chambers formed between a 
container and the shell and core are open at the bottom. The container 
rests on the ledges 55 on the centering ring, as in the pot assembly 38, 
but the lid is provided with pins 140 which project into the cavity and 
which are adapted to engage a container therein to space lid from the top 
of the container. In operation, cleaning liquid is supplied to the outer 
and inner chambers through the pipe 30 and duct 50 and escapes through the 
openings at the bottom of the chambers. 
The pot assembly of FIG. 9 is similar to that of FIG. 8, except that a seal 
141 is provided between the bottom of the shell and the support plate 36. 
Cleaning liquid supplied through either the pipe 30 or duct 50 flows in 
succession through the two chambers, as in the pot assembly 38, and 
exhaust through the duct 50 or pipe 30 respectively. 
The pot assembly of FIG. 10 has a shell and core similar to that of the pot 
assembly 38, but is provided with exhaust ducts 142, 143 at the bottom of 
the cavity so that cleaning liquid can be fed simultaneously through the 
pipe 30 and duct 50 into the two chambers formed between a container and 
the core and shell. The lid is spaced from a container in the cavity by 
pins 140 and an O ring seal 144 is provided between the cover plate 60 of 
the lid and the top of the shell.